Practice nursing care for clients with Diabetes
Mellitus II
Diabetes mellitus is a group of metabolic diseases characterized by
elevated levels of glucose in the blood (hyperglycemia) resulting from
defects in insulin secretion, insulin action, or both (American Diabetes
Association [
Insulin, a hormone produced by the pancreas, controls the
level of glucose in the blood by regulating the production and storage of
glucose. In the diabetic state, the cells may stop responding to insulin or the
pancreas may stop producing insulin entirely. This leads to hyperglycemia,
which may result in acute metabolic complications such as diabetic
ketoacidosis (DKA) and hyperglycemic hyperosmolar nonketotic syndrome (HHNS).
Long-term effects of hyperglycemia contribute to macrovascular complications
(coronary artery disease, cerebrovascular disease, and peripheral vascular
disease), chronic microvascular complications (kidney and eye disease), and
neuropathic complications (diseases of the nerves). Diabetes mellitus affects
about 17 million people, 5.9 million of whom are undiagnosed. In the
The far-reaching and devastating physical,
social, and economic consequences of diabetes are as follows:
• In the
• Diabetes is the third leading cause of death by
disease, primarily because of the high rate of cardiovascular disease
(myocardial infarction, stroke, and peripheral vascular disease) among people
with diabetes.
• Hospitalization rates for people with diabetes are 2.4
times greater for adults and 5.3 times greater for children than for the
general population.
The economic cost
of diabetes continues to rise because of increasing health care costs and an
aging population. Half of all people who have diabetes and who are older than
65 are hospitalized each year, and severe and life-threatening complications
often contribute to the increased rates of hospitalization. Costs related to
diabetes are estimated to be almost $100 billion annually, including direct
medical care expenses and indirect costs attributable to disability and
premature death (CDC, 2002). The primary goals of treatment for patients with
diabetes include controlling blood glucose levels and preventing acute and
long-term complications. Thus, the nurse who cares for diabetic patients must
assist them to develop self-care management skills.
Classification of Diabetes
There are several
different types of diabetes mellitus; they may differ in cause, clinical
course, and treatment. The major classifications of diabetes are:
• Type 1 diabetes (previously referred to as insulin-dependent diabetes
mellitus)
• Type 2 diabetes (previously referred to as non-insulindependent
diabetes mellitus)
• Gestational diabetes mellitus (
• Diabetes mellitus associated with other conditions or
syndromes
OVERVIEW
The terms
“insulin-dependent diabetes” and “non-insulindependent diabetes” and their
acronyms (IDDM and NIDDM, respectively) are no longer used because they have
resulted in classification of patients on the basis of the treatment of their
diabetes rather than the underlying etiology. Use of Roman numerals (type I and
type II) to distinguish between the two types has been changed to type 1 and
type 2 to reduce confusion (
Borderline
diabetes is classified as impaired glucose tolerance (IGT) or impaired
fasting glucose (IFG) and refers to a condition in which blood glucose
levels fall between normal levels and levels considered diagnostic for
diabetes. This classification system is dynamic in two ways. First, research
findings suggest many differences among individuals within each category.
Second, except for those with type 1 diabetes, patients may move from one
category to another. For example, a woman with gestational diabetes may, after
delivery, move into the type 2 category. These types also differ in their
etiology, clinical course, and management.
PHYSIOLOGY AND PATHOPHYSIOLOGY OF DIABETES
Insulin is
secreted by beta cells, which are one of four types of cells in the islets of
Langerhans in the pancreas.
Insulin is an
anabolic, or storage, hormone. When a person eats a meal, insulin secretion
increases and moves glucose from the blood into muscle, liver, and fat cells.
In those cells,
insulin:
• Transports and metabolizes glucose for energy
• Stimulates storage of glucose in the liver and muscle
(in the form of glycogen)
• Signals the liver to stop the release of glucose
• Enhances storage of dietary fat in adipose tissue
• Accelerates transport of amino acids (derived from
dietary protein) into cells Insulin also inhibits the breakdown of stored
glucose, protein, and fat.
During fasting
periods (between meals and overnight), the pancreas continuously releases a
small amount of insulin (basal insulin); another pancreatic hormone called
glucagon (secreted by the alpha cells of the islets of Langerhans) is released
when blood glucose levels decrease and stimulate the liver to release stored
glucose. The insulin and the glucagon together maintain a constant level of
glucose in the blood by stimulating the release of glucose from the liver.
Initially, the liver produces glucose through the breakdown of glycogen
(glycogenolysis). After 8 to 12 hours without food, the liver forms glucose
from the breakdown of noncarbohydrate substances, including amino acids
(gluconeogenesis).
TYPE 1 DIABETES
Type 1 diabetes is
characterized by destruction of the pancreatic beta cells. It is thought that
combined genetic, immunologic, and possibly environmental (eg, viral) factors
contribute to beta cell destruction. Although the events that lead to beta cell
destruction are not fully understood, it is generally accepted that a genetic
susceptibility is a common underlying factor in the development of type 1 diabetes.
People do not inherit type 1 diabetes itself; rather, they inherit a genetic
predisposition, or tendency, toward developing type 1 diabetes. This genetic
tendency has been found in people with certain HLA (human leukocyte antigen)
types. HLA refers to a cluster of genes responsible for transplantation
antigens and other immune processes. About 95% of Caucasians with type 1
diabetes exhibit specific HLA types (DR3 or DR4). The risk of developing type 1
diabetes is increased three to five times in people who have one of these two
HLA types. The risk increases 10 to 20 times in people who have both DR3 and
DR4 HLA types (as compared with the general population). Immune-mediated
diabetes commonly develops during childhood and adolescence, but it can occur at
any age (ADA, Expert Committee on the Diagnosis and Classification of Diabetes
Mellitus, 2003). There is also evidence of an autoimmune response in type 1
diabetes. This is an abnormal response in which antibodies are directed against
normal tissues of the body, responding to these tissues as if they are foreign.
Autoantibodies
against islet cells and against endogenous (internal) insulin have been
detected in people at the time of diagnosis and even several years before the
development of clinical signs of type 1 diabetes. In
addition to genetic and immunologic components, environmental factors, such as
viruses or toxins, that may initiate destruction of the beta cell are being
investigated. Regardless of the specific etiology, the destruction of the beta cells
results in decreased insulin production, unchecked glucose production by the
liver, and fasting hyperglycemia. In addition, glucose derived from food cannot
be stored in the liver but instead remains in the bloodstream and contributes
to postprandial (after meals) hyperglycemia. If the concentration of glucose in
the blood exceeds the renal threshold for glucose, usually 180 to 200 mg/dL
(9.9 to 11.1 mmol/L), the kidneys may not reabsorb all of the filtered glucose;
the glucose then appears in the urine (glucosuria). When excess glucose is
excreted in the urine, it is accompanied by excessive loss of fluids and
electrolytes. This is called osmotic diuresis. Because insulin normally
inhibits glycogenolysis (breakdown of stored glucose) and gluconeogenesis
(production of new glucose from amino acids and other substrates), in people
with insulin deficiency, these processes occur in an unrestrained fashion and
contribute further to hyperglycemia. In addition, fat breakdown occurs,
resulting in an increased production of ketone bodies, which are the
byproducts of fat breakdown.
TYPE 2 DIABETES
The two main
problems related to insulin in type 2 diabetes are insulin resistance and
impaired insulin secretion. Insulin resistance refers to a decreased tissue sensitivity
to insulin. Normally, insulin binds to special receptors on cell surfaces and
initiates a series of reactions involved in glucose metabolism. In type 2
diabetes, these intracellular reactions are diminished, thus rendering insulin
less effective at stimulating glucose uptake by the tissues and at regulating
glucose release by the liver (Fig. 41-1). The exact mechanisms that lead to
insulin resistance and impaired insulin secretion in type 2 diabetes are
unknown, although genetic factors are thought to play a role. To overcome
insulin resistance and to prevent the buildup of glucose in the blood,
increased amounts of insulin must be secreted to maintain the glucose level at
a normal or slightly elevated level. However, if the beta cells cannot keep up
with the increased demand for insulin, the glucose level rises, and type 2
diabetes develops. Despite the impaired insulin secretion that is
characteristic of type 2 diabetes, there is enough insulin present to prevent
the breakdown of fat and the accompanying production of ketone bodies.
Therefore, DKA does not typically occur in type 2 diabetes. Uncontrolled type 2
diabetes may, however, lead to another acute problem, HHNS (see later
discussion).
Type 2 diabetes occurs
most commonly in people older than 30 years who are obese, although its
incidence is increasing in younger adults (CDC, Diabetes Surveillance, 2002).
Because it is associated with a slow (over years), progressive glucose
intolerance, the onset of type 2 diabetes may go undetected for many years. If
symptoms are experienced, they are frequently mild and may include fatigue,
irritability, polyuria, polydipsia, skin wounds that heal poorly, vaginal
infections, or blurred vision (if glucose levels are very high).
For most patients (approximately 75%), type 2
diabetes is detected incidentally (eg, when routine laboratory tests or
ophthalmoscopic examinations are performed). One consequence of undetected
diabetes is that long-term diabetes complications (eg, eye disease, peripheral
neuropathy, peripheral vascular disease) may have developed before the actual
diagnosis of diabetes is made (ADA, Expert Committee on the Diagnosis and
Classification of Diabetes Mellitus, 2003). Because insulin resistance is associated
with obesity, the primary treatment of type 2 diabetes is weight loss. Exercise
is also important in enhancing the effectiveness of insulin. Oral antidiabetic
agents may be added if diet and exercise are not successful in controlling
blood glucose levels. If maximum doses of a single category of oral agents fail
to reduce glucose levels to satisfactory levels, additional oral agents may be
used. Insulin may be added to oral agent therapy, or patients may move to
insulin therapy entirely. Some patients require insulin on an ongoing basis,
and others may require insulin on a temporary basis during periods of acute
physiologic stress, such as illness or surgery. A recent report has
demonstrated that type 2 diabetes can be prevented or delayed in persons at
high risk for the disease through weight reduction and increased participation
in moderate exercise (Diabetes Prevention Program Research Group, 2002).
Metformin, one of the antidiabetic agents, also prevented or delayed the onset
of type 2 diabetes, but to a lesser degree.
GESTATIONAL
DIABETES
Gestational
diabetes is any degree of glucose intolerance with its onset during pregnancy.
Hyperglycemia develops during pregnancy because of the secretion of placental
hormones, which causes insulin resistance. For women who meet one or more of
the following criteria, selective screening for diabetes during pregnancy is
now being recommended between the 24th and 28th weeks of gestation: age 25
years or older; age 25 years or younger and obese; family history of diabetes
in first-degree relatives; or member of an ethnic/racial group with a high
prevalence of diabetes (eg, Hispanic American, Native American, Asian American,
African American, or Pacific Islander). Gestational diabetes occurs in up to
14% of pregnant women and increases their risk for hypertensive disorders
during pregnancy (ADA, Gestational Diabetes Mellitus, 2003). Initial management
includes dietary modification and blood glucose monitoring. If hyperglycemia
persists, insulin is prescribed. Oral antidiabetic agents should not be used
during pregnancy. Goals for blood glucose levels during pregnancy are 105 mg/dL
(5.8 mmol/L) or less before meals and 120 mg/dL (6.7 mmol/L) or less 2 hours
after meals (ADA, Gestational Diabetes Mellitus, 2003). After delivery of the
infant, blood glucose levels in the woman with gestational diabetes return to
normal. However, many women who have had gestational diabetes develop type 2
diabetes later in life. Therefore, all women who have had gestational diabetes
should be counseled to maintain their ideal body weight and to exercise
regularly to reduce their risk for type 2 diabetes (ADA, Gestational Diabetes
Mellitus, 2003).
CLINICAL
MANIFESTATIONS
Clinical
manifestations of all types of diabetes include the “three Ps”: polyuria,
polydipsia, and polyphagia.
Polyuria
(increased urination) and polydipsia (increased thirst) occur as a result of
the excess loss of fluid associated with osmotic diuresis.
The patient also
experiences polyphagia (increased appetite) resulting from the catabolic state
induced by insulin deficiency and the breakdown of proteins and fats. Other
symptoms include fatigue and weakness, sudden vision changes, tingling or
numbness in hands or feet, dry skin, skin lesions or wounds that are slow to
heal, and recurrent infections. The onset of type 1 diabetes may also be
associated with sudden weight loss or nausea, vomiting, or abdominal pains, if
DKA has developed.
ASSESSMENT AND
DIAGNOSTIC FINDINGS
An abnormally high
blood glucose level is the basic criterion for the diabetes diagnosis.
Fasting plasma
glucose (FPG) levels of
126 mg/dL (7.0 mmol/L) or more or random plasma glucose levels exceeding 200
mg/dL (11.1 mmol/L) on more than one occasion are diagnostic of diabetes. The
oral glucose tolerance test and the intravenous glucose tolerance test are no
longer recommended for routine clinical use. See Chart 41-3 for the ADA’s
diagnostic criteria for diabetes mellitus (ADA, Expert Committee on the
Diagnosis and Classification of Diabetes Mellitus, 2003). Plasma glucose values
may be 10% to 15% higher than whole blood values, which are obtained with
finger sticks (Porth, 2002). In addition to the assessment and diagnostic
evaluation performed to diagnose diabetes, ongoing specialized assessment of
patients with known diabetes and evaluation for complications in patients with
newly diagnosed diabetes are important components of care.
Gerontologic Considerations
Elevated blood glucose levels appear
to be age-related and occur in both men and women throughout the world.
Elevated blood glucose levels commonly appear in the fifth decade of life and
increase in frequency with advancing age. When elderly people with overt
diabetes are excluded from the statistics, approximately 10% to 30% of elderly
people have age-related hyperglycemia. What causes age-related changes in
carbohydrate metabolism is unresolved. Possibilities
include poor diet, physical inactivity, a decrease in the lean body mass in which
ingested carbohydrate may be stored, altered insulin secretion, and increase in
fat tissue, which increases insulin resistance.
Diabetes Management
The main goal of
diabetes treatment is to normalize insulin activity and blood glucose levels to
reduce the development of vascular and neuropathic complications. The
importance of tight blood glucose control was demonstrated by the Diabetes
Control and Complications Trial (DCCT), a 10-year prospective clinical trial
conducted from 1983 to 1993. The trial investigated the impact of intensive
glucose control on the development and progression of complications such as retinopathy,
nephropathy, and neuropathy.
A cohort of 1,441
people with type 1 diabetes were randomly assigned to conventional treatment (one or
two insulin injections per day) or intensive treatment (three or four insulin
injections per day or insulin pump therapy plus frequent blood glucose
monitoring and weekly contacts with diabetes educators). Results demonstrated
that the risk for developing retinopathy, neuropathy, and early signs of
nephropathy (microalbuminuria and albuminuria) was dramatically reduced. The
reduction was attributed to control of blood glucose levels to normal or
nearnormal levels. The
The major adverse
effect of intensive therapy was a threefold increase in the incidence of severe
hypoglycemia (severe enough to require assistance from another person),
coma, or seizure. Because of these adverse effects, intensive therapy must be
initiated with caution and must be accompanied by thorough education of the
patient and family and by responsible behavior of the patient. Careful
screening of patients is a key step in initiating intensive therapy. (For
situations that preclude the initiation of very tight blood glucose control,
see the discussion of insulin in this chapter.) A study conducted in the United
Kingdom and reported in 1998 supported the results of the DCCT in type 2
diabetes and demonstrated a decrease in complications in patients with type 2
diabetes receiving intensive therapy compared to those receiving conventional
therapy (United Kingdom Prospective Diabetes Study Group [UKPDS], 1998; ADA,
Implications of the United Kingdom Prospective Diabetes Study, 2003).
Therefore, the therapeutic goal for diabetes management is to achieve normal
blood glucose levels (euglycemia) without hypoglycemia and without seriously
disrupting the patient’s usual lifestyle and activity.
There are five
components of diabetes management:
• Nutritional management
• Exercise
• Monitoring
• Pharmacologic therapy
• Education Treatment varies because of changes in
lifestyle and physical and emotional status as well as advances in treatment
methods.
Therefore,
diabetes management involves constant assessment and modification of the
treatment plan by health professionals and daily adjustments in therapy by the
patient. Although the health care team directs the treatment, it is the patient
who must manage the complex therapeutic regimen. For this reason, patient and
family education is an essential component of diabetes treatment and is as
important as all other components of the regimen.
NUTRITIONAL MANAGEMENT
Nutrition, diet,
and weight control are the foundation of diabetes management. The most
important objective in the dietary and nutritional management of diabetes is
control of total caloric intake to attain or maintain a reasonable body weight
and control of blood glucose levels. Success of this alone is often associated
with reversal of hyperglycemia in type 2 diabetes. However, achieving this goal
is not always easy. Because nutritional man- agement of diabetes is so complex,
a registered dietitian who understands diabetes management has the major
responsibility for this aspect of the therapeutic plan. However, the nurse and
all other members of the health care team need to be knowledgeable about
nutritional therapy and supportive of the patient who needs to implement
dietary and lifestyle changes (
Nutritional management of the diabetic patient
includes the following goals (
• Providing all the essential food constituents (eg,
vitamins, minerals) necessary for optimal nutrition
• Meeting energy needs
• Achieving and maintaining a reasonable weight
• Preventing wide daily fluctuations in blood glucose
levels, with blood glucose levels as close to normal as is safe and practical
to prevent or reduce the risk for complications
• Decreasing serum lipid levels, if elevated, to reduce
the risk for macrovascular disease
For patients who
require insulin to help control blood glucose levels, maintaining as much
consistency as possible in the amount of calories and carbohydrates ingested at
different meal times is essential. In addition, consistency in the approximate
time intervals between meals, with the addition of snacks if necessary, helps
in preventing hypoglycemic reactions and in maintaining overall blood glucose
control. For obese diabetic patients (especially those with type 2 diabetes),
weight loss is the key to treatment. (It is also a major factor in preventing
diabetes.) In general, overweight is considered to be a body mass index (BMI)
of 25 to 29; obesity is defined as 20% above ideal body weight or a BMI equal
to or greater than 30 (National Institutes of Health, 2000). BMI is a
weight-to-height ratio calculated by dividing body weight (in kilograms) by the
square of the height (in meters). Calculation of BMI is discussed in Chapter 5.
Obesity is
associated with an increased resistance to insulin; it is also a main factor in
type 2 diabetes. Some obese patients who have type 2 diabetes and who require
insulin or oral agents to control blood glucose levels may be able to reduce or
eliminate the need for medication through weight loss. A weight loss as small
as 10% of total weight may significantly improve blood glucose levels. For
obese diabetic patients who do not take insulin, consistent meal content or
timing is not as critical. Rather, decreasing the overall caloric intake
assumes more importance. However, meals should not be skipped. Pacing food
intake throughout the day places more manageable demands on the pancreas. Long-term
adherence to the meal plan is one of the most challenging aspects of diabetes
management. For obese patients, it may be more realistic to restrict calories
only moderately. For those who have lost weight, maintaining the weight loss
may be difficult. To help these patients incorporate new dietary habits into
their lifestyles, diet education, behavioral therapy, group support, and
ongoing nutrition counseling are encouraged.
Meal Planning and
Related Teaching
For all patients
with diabetes, the meal plan must consider the patient’s food preferences,
lifestyle, usual eating times, and ethnic and cultural background. For patients
using intensive insulin therapy, there may be greater flexibility in the timing
and content of meals by allowing adjustments in insulin dosage for changes in
eating and exercise habits. Advances in insulin management (new insulin
analogs, insulin algorithms, insulin pumps) permit greater flexibility of
schedules than previously possible. This is in contrast to the older concept of
maintaining a constant dose of insulin and requiring the patient to adjust his
or her schedule to the actions and duration of the insulin. The first step in
preparing a meal plan is a thorough review of the patient’s diet history to
identify his or her eating habits and lifestyle. A thorough assessment of the
patient’s need for weight loss, gain, or maintenance is also undertaken. In
most instances, the person with type 2 diabetes requires weight reduction. In
teaching about meal planning, the clinical dietitian uses various educational
tools, materials, and approaches. Initial education addresses the importance of
consistent eating habits, the relationship of food and insulin, and the
provision of an individualized meal plan. In-depth follow-up education then
focuses on management skills, such as eating at restaurants, reading food
labels, and adjusting the meal plan for exercise, illness, and special
occasions. The nurse plays an important role in communicating pertinent
information to the dietitian and reinforcing the patient’s understanding. For
some patients, certain aspects of meal planning, such as the food exchange
system, may be difficult to learn. This may be related to limitations in the
patient’s intellectual level or to emotional issues, such as difficulty
accepting the diagnosis of diabetes or feelings of deprivation and undue
restriction in eating. In any case, it helps to emphasize that using the
exchange system (or any food classification system) provides a new way of
thinking about food rather than a new way of eating. It is also important to
simplify information as much as possible and to provide opportunities for the
patient to practice and repeat activities and information.
CALORIC REQUIREMENTS
Calorie-controlled
diets are planned by first calculating the individual’s energy needs and
caloric requirements based on the patient’s age, gender, height, and weight. An
activity element is then factored in to provide the actual number of calories
required for weight maintenance. To promote a 1- to 2-pound weight loss per
week, 500 to 1,000 calories are subtracted from the daily total. The calories
are distributed into carbohydrates, proteins, and fats, and a meal plan is then
developed. The 1995 Exchange Lists for Meal Planning (ADA, 1995) are presented
to the patient using the appropriate amount of calories, with strict diet
adherence as the goal. Unfortunately, caloriecontrolled diets are often
confusing and difficult to comply with. They require patients to measure
precise portions and to eat specific foods and amounts at each meal and snack.
In this instance, developing a meal plan based on the individual’s usual eating
habits and lifestyle may be a more realistic approach to glucose control and
weight loss or weight maintenance. In both instances, the patient needs to work
closely with a registered dietitian to assess current eating habits and to
achieve realistic, individualized goals. The priority for a young patient with
type 1 diabetes, for example, should be a diet with enough calories to maintain
normal growth and development. Some patients may be underweight at the onset of
type 1 diabetes because of rapid weight loss from severe hyperglycemia. The
goal with these patients initially may be to provide a higher-calorie diet to
regain lost weight.
CALORIC
DISTRIBUTION
A diabetic meal
plan also focuses on the percentage of calories to come from carbohydrates,
proteins, and fats. In general, carbohydrate foods have the greatest effect on
blood glucose levels because they are more quickly digested than other foods
and are converted into glucose rapidly. Several decades ago it was recommended
that diabetic diets contain more calories from protein and fat foods than from
carbohydrates to reduce postprandial increases in blood glucose levels. However,
this resulted in a dietary intake inconsistent with the goal of reducing the
cardiovascular disease commonly associated with diabetes (ADA, Evidence-Based
Nutrition Principles and Recommendations for the Treatment and Prevention of
Diabetes and Related Complications, 2003).
Carbohydrates.
The caloric
distribution currently recommended is higher in carbohydrates than in fat and
protein. However, research into the appropriateness of a higher-carbohydrate
diet in patients with decreased glucose tolerance is ongoing, and
recommendations may change accordingly. Currently, the ADA and the American
Dietetic Association recommend that for all levels of caloric intake, 50% to
60% of calories should be derived from carbohydrates, 20% to 30% from fat, and
the remaining 10% to 20% from protein. These recommendations are also
consistent with those of the American Heart Association, American Cancer
Society, and the U.S. Department of Agriculture (2000). Carbohydrates consist
of sugars and starches. Little scientific evidence supports the belief that
sugars, such as sucrose, promote a greater blood glucose level compared to
starches (eg, rice, pasta, or bread). Although low glycemic index diets
(described below) may reduce postprandial glucose levels, there seem to be no
clear effects on outcomes (ADA, Expert Committee on the Diagnosis and
Classification of Diabetes Mellitus, 2003). Thus, the latest nutrition
guidelines recommend that all carbohydrates be eaten in moderation to avoid
high postprandial blood glucose levels (ADA, Exchange Lists for Meal Planning,
1995). Foods high in carbohydrates, such as sucrose, are not eliminated from
the diet but should be eaten in moderation (up to 10% of total calories)
because these foods are typically high in fat and lack vitamins, minerals, and
fiber. Carbohydrate counting is another nutritional tool used for blood glucose
management because carbohydrates are the main nutrients in food that influence
blood glucose levels. This method provides flexibility in food choices, can be
less complicated to understand than the diabetic food exchange list, and allows
more accurate management with multiple daily injections (insulin before each
meal). However, if carbohydrate counting is not used with other meal-planning
techniques, weight gain can result. A variety of methods are used to count
carbohydrates. When developing a diabetic meal plan using carbohydrate
counting, all food sources should be considered. Once digested, 100% of
carbohydrates are converted to glucose. However, approximately 50% of protein
foods (meat, fish, and poultry) are also converted to glucose. One method of
carbohydrate counting includes counting grams of carbohydrates. If target goals
are not reached by counting carbohydrates alone, protein will be factored into the
calculations. This is especially true if the meal consists of only meat, fish,
and non-starchy vegetables. An alternative to counting grams of carbohydrate is
measuring servings or choices. This method is used more often by people with
type 2 diabetes. It is similar to the food exchange list and emphasizes portion
control of total servings of carbohydrate at meals and snacks. One carbohydrate
serving is equivalent to
Fats.
The
recommendations regarding fat content of the diabetic diet include both
reducing the total percentage of calories from fat sources to less than 30% of
the total calories and limiting the amount of saturated fats to 10% of total
calories. Additional recommendations include limiting the total intake of
dietary cholesterol to less than 300 mg/day. This approach may help to reduce
risk factors such as elevated serum cholesterol levels, which are associated
with the development of coronary artery disease, the leading cause of death and
disability among people with diabetes. The meal plan may include the use of
some nonanimal sources of protein (eg, legumes and whole grains) to help reduce
saturated fat and cholesterol intake. In addition, the amount of protein intake
may be reduced in patients with early signs of renal disease.
Fiber.
The use of fiber
in diabetic diets has received increased attention as researchers study the
effects on diabetes of a highcarbohydrate, high-fiber diet. This type of diet
plays a role in lowering total cholesterol and low-density lipoprotein
cholesterol in the blood. Increasing fiber in the diet may also improve blood
glucose levels and decrease the need for exogenous insulin. There are two types
of dietary fibers: soluble and insoluble. Soluble fiber—in foods such as
legumes, oats, and some fruits— plays more of a role in lowering blood glucose
and lipid levels than does insoluble fiber, although the clinical significance
of this effect is probably small (ADA, Expert Committee on the Diagnosis and
Classification of Diabetes Mellitus, 2003). Soluble fiber is thought to be
related to the formation of a gel in the GI tract. This gel slows stomach
emptying and the movement of food through the upper digestive tract. The
potential glucose-lowering effect of fiber may be caused by the slower rate of
glucose absorption from foods that contain soluble fiber. Insoluble fiber is
found in whole-grain breads and cereals and in some vegetables. This type of
fiber plays more of a role in increasing stool bulk and preventing
constipation. Both insoluble and soluble fibers increase satiety, which is
helpful for weight loss. One risk involved in suddenly increasing fiber intake
is that it may require adjusting the dosage of insulin or oral agents to
prevent hypoglycemia. Other problems may include abdominal fullness, nausea,
diarrhea, increased flatulence, and constipation if fluid intake is inadequate.
If fiber is added to or increased in the meal plan, it should be done gradually
and in consultation with a dietitian. The 1995 Exchange Lists for Meal Planning
(ADA, 1995) is an excellent guide for increasing fiber intake. Fiber-rich food
choices within the vegetable, fruit, and starch/bread exchanges are highlighted
in the lists.
FOOD CLASSIFICATION
SYSTEMS
To teach diet
principles and to help patients in meal planning, several systems have been
developed in which foods are organized into groups with common characteristics,
such as number of calories, composition of foods (ie, amount of protein, fat,
or carbohydrate in the food), or effect on blood glucose levels.
Exchange Lists.
A commonly used
tool for nutritional management is the Exchange Lists for Meal Planning (
The
Food Guide Pyramid.
The Food Guide Pyramid
is another tool used to develop meal plans. It is commonly used for patients
with type 2 diabetes who have a difficult time complying with a
calorie-controlled diet.
The food pyramid
consists of six food groups:
(1) bread, cereal, rice, and pasta;
(2) fruits;
(3) vegetables;
(4) meat, poultry,
fish, dry beans, eggs, and nuts;
(5) milk, yogurt, and cheese;
and (6) fats, oils, and sweets.
The pyramid shape
was chosen to emphasize that the foods in the largest area, the base of the
pyramid (starches, fruits, and vegetables), are lowest in calories and fat and
highest in fiber and should make up the basis of the diet. For those with
diabetes, as well as for the general population, 50% to 60% of the daily
caloric intake should be from these three groups. As one moves up the pyramid,
foods higher in fat (particularly saturated fat) are illustrated; these foods
should account for a smaller percentage of the daily caloric intake. The very
top of the pyramid comprises fats, oils, and sweets, foods that should be used
sparingly by people with diabetes to obtain weight and blood glucose control
and to reduce the risk for cardiovascular disease. Reliance on the Food Guide
Pyramid, however, may result in fluctuations in blood glucose levels because
high-carbohydrate foods may be grouped with low-carbohydrate foods. The pyramid
is appropriately used only as a first-step teaching tool (Dixon, Cronin, &
Krebs-Smith, 2001) for patients learning how to control food portions and how
to identify which foods contain carbohydrate, protein, and fat.
Glycemic Index.
One of the main
goals of diet therapy in diabetes is to avoid sharp, rapid increases in blood
glucose levels after food is eaten. The term “glycemic index” is used to
describe how much a given food raises the blood glucose level compared with an
equivalent amount of glucose; however, the effects on blood glucose levels and
on long-term patient outcomes have been questioned (
Although more
research is necessary, the following guidelines can be helpful when making
dietary recommendations:
• Combining starchy foods with protein- and
fat-containing foods tends to slow their absorption and lower the glycemic
response.
• In general, eating foods that are raw and whole
results in a lower glycemic response than eating chopped, pured, or cooked
foods.
• Eating whole fruit instead of drinking juice decreases
the glycemic response because fiber in the fruit slows absorption.
• Adding foods with sugars to the diet may produce a
lower glycemic response if these foods are eaten with foods that are more
slowly absorbed.
Patients can
create their own glycemic index by monitoring their blood glucose level after
ingesting a particular food. This can help patients improve blood glucose
levels through individualized manipulation of the diet. Many patients who use
frequent monitoring of blood glucose levels can use this information to adjust
their insulin doses for variations in food intake.
Other Dietary Concerns
ALCOHOL CONSUMPTION
Patients with
diabetes do not need to give up alcoholic beverages entirely, but patients and
health care professionals need to be aware of the potential adverse effects of
alcohol specific to diabetes. In general, the same precautions regarding the
use of alcohol by people without diabetes should be applied to patients with
diabetes. Moderation is recommended. The main danger of alcohol consumption by
a diabetic patient is hypoglycemia, especially for patients who take insulin.
Alcohol may decrease the normal physiologic reactions in the body that produce
glucose (gluconeogenesis). Thus, if a diabetic patient takes alcohol on an
empty stomach, there is an increased likelihood that hypoglycemia will develop.
In addition, excessive alcohol intake may impair the patient’s ability to
recognize and treat hypoglycemia and to follow a prescribed meal plan to
prevent hypoglycemia. To reduce the risk of hypoglycemia, the patient should be
cautioned to eat while drinking alcohol (ADA, Expert Committee on the Diagnosis
and Classification of Diabetes Mellitus, 2003).
For the person
with type 2 diabetes treated with the sulfonylurea agent chlorpropamide
(Diabinese), a potential side effect of alcohol consumption is a disulfiram
(Antabuse) type of reaction, which involves facial flushing, warmth, headache,
nausea, vomiting, sweating, or thirst within minutes of consuming alcohol. The
intensity of the reaction depends on the amount of alcohol consumed; the
reaction seems to be less common with other sulfonylureas. Alcohol consumption
may lead to excessive weight gain (from the high caloric content of alcohol),
hyperlipidemia, and elevated glucose levels (especially with mixed drinks and
liqueurs). Patient teaching regarding alcohol intake must emphasize moderation
in the amount of alcohol consumed. Lower-calorie or less sweet drinks, such as
light beer or dry wine, and food intake along with alcohol consumption are
advised. For patients with type 2 diabetes especially, incorporating the
calories from alcohol into the overall meal plan is important for weight
control.
SWEETENERS
Using sweeteners
is acceptable for patients with diabetes, especially if it assists in overall dietary
adherence. Moderation in the amount of sweetener used is encouraged to avoid
potential adverse effects. There are two main types of sweeteners: nutritive
and non-nutritive. The nutritive sweeteners contain calories, and the
non-nutritive sweeteners have few or no calories in the amounts normally used.
Nutritive sweeteners include fructose (fruit sugar), sorbitol, and xylitol.
They are not calorie-free; they provide calories in amounts similar to those in
sucrose (table sugar). They cause less elevation in blood sugar levels than
sucrose and are often used in “sugar-free” foods. Sweeteners containing
sorbitol may have a laxative effect. Non-nutritive sweeteners have minimal or
no calories. They are used in food products and are also available for table
use. They produce minimal or no elevation in blood glucose levels and have been
approved by the Food and Drug Administration as safe for people with diabetes.
Saccharin contains no calories. Aspartame (NutraSweet) is packaged with
dextrose; it contains 4 calories per packet and loses sweetness with heat.
Acesulfame-K (Sunnette) is also packaged with dextrose; it contains 1 calorie
per packet. Sucralose (Splenda) is a newer non-nutritive, high-intensity
sweetener that is about 600 times sweeter than sugar. The Food and Drug
Administration has approved it for use in baked goods, nonalcoholic beverages,
chewing gum, coffee, confections, frostings, and frozen dairy products.
MISLEADING FOOD
LABELS
Foods labeled
“sugarless” or “sugar-free” may still provide calories equal to those of the
equivalent sugar-containing products if they are made with nutritive
sweeteners. Thus, for weight loss, these products may not always be useful. In
addition, patients must not consider them “free” foods to be eaten in unlimited
quantity, because they may elevate blood glucose levels. Foods labeled
“dietetic” are not necessarily reduced-calorie foods. They may be lower in
sodium or have other special dietary uses. Patients are advised that foods
labeled “dietetic” may still contain significant amounts of sugar or fat.
Patients must also be taught to read the labels of “health foods”—especially
snacks—because they often contain carbohydrates such as honey, brown sugar, and
corn syrup. In addition, these supposedly healthy snacks frequently contain
saturated vegetable fats (eg, coconut or palm oil), hydrogenated vegetable
fats, or animal fats, which may be contraindicated in patients with elevated
blood lipid levels.
EXERCISE Benefits
Exercise is
extremely important in managing diabetes because of its effects on lowering
blood glucose and reducing cardiovascular risk factors. Exercise lowers the
blood glucose level by increasing the uptake of glucose by body muscles and by
improving insulin utilization. It also improves circulation and muscle tone.
Resistance (strength) training, such as weight lifting, can increase lean
muscle mass, thereby increasing the resting metabolic rate. These effects are
useful in diabetes in relation to losing weight, easing stress, and maintaining
a feeling of well-being. Exercise also alters blood lipid levels, increasing
levels of high-density lipoproteins and decreasing total cholesterol and
triglyceride levels. This is especially important to the person with diabetes
because of the increased risk of cardiovascular disease (Creviston & Quinn,
2001).
Exercise
Precautions
Patients who have
blood glucose levels exceeding 250 mg/dL (14 mmol/L)
and who have ketones in their urine should not begin exercising until the urine
tests negative for ketones and the blood glucose level is closer to normal.
Exercising with elevated blood glucose levels increases the secretion of
glucagon, growth hormone, and catecholamines. The liver then releases more
glucose, and the result is an increase in the blood glucose level (ADA,
Physical Activity/Exercise and Diabetes Mellitus, 2003). The physiologic
decrease in circulating insulin that normally occurs with exercise cannot occur
in patients treated with insulin. Initially, the patient who requires insulin
should be taught to eat a 15-g carbohydrate snack (a fruit exchange) or a snack
of complex carbohydrate with a protein before engaging in moderate exercise, to
prevent unexpected hypoglycemia. The exact amount of food needed varies from
person to person and should be determined by blood glucose monitoring. Some
patients find that they do not require a pre-exercise snack if they exercise
within 1 to 2 hours after a meal. Other patients may require extra food
regardless of when they exercise. If extra food is required, it need not be
deducted from the regular meal plan. Another potential problem for patients who
take insulin is hypoglycemia that occurs many hours after exercise.
To avoid
postexercise hypoglycemia, especially after strenuous or prolonged exercise,
the patient may need to eat a snack at the end of the exercise session and at
bedtime and monitor the blood glucose level more frequently. In addition, it
may be necessary to have the patient reduce the dosage of insulin that peaks at
the time of exercise. Patients who are capable, knowledgeable, and responsible
can learn to adjust their own insulin doses. Others need specific instructions
on what to do when they exercise. Patients participating in extended periods of
exercise should test their blood glucose levels before, during, and after the
exercise period, and they should snack on carbohydrates as needed to maintain
blood glucose levels (ADA, Physical Activity/Exercise and Diabetes Mellitus,
2003). Other participants or observers should be aware that the person exercising
has diabetes, and they should know what assistance to give if severe
hypoglycemia occurs. In obese people with type 2 diabetes, exercise in addition
to dietary management both improves glucose metabolism and enhances loss of
body fat. Exercise coupled with weight loss improves insulin sensitivity and
may decrease the need for insulin or oral agents. Eventually, the patient’s
glucose tolerance may return to normal. The patient with type 2 diabetes who is
not taking insulin or an oral agent may not need extra food before exercise.
Exercise
Recommendations
People with
diabetes should exercise at the same time (preferably when blood glucose levels
are at their peak) and in the same amount each day. Regular daily exercise,
rather than sporadic exercise, should be encouraged. Exercise recommendations
must be altered as necessary for patients with diabetic complications such as
retinopathy, autonomic neuropathy, sensorimotor neuropathy, and cardiovascular
disease (ADA, Physical Activity/Exercise and Diabetes Mellitus, 2003).
Increased blood pressure associated with exercise may aggravate diabetic
retinopathy and increase the risk of a hemorrhage into the vitreous or retina.
Patients with ischemic heart disease risk triggering angina or a myocardial
infarction, which may be silent. Avoiding trauma to the lower extremities is
especially important in the patient with numbness related to neuropathy. In
general, a slow, gradual increase in the exercise period is encouraged. For
many patients, walking is a safe and beneficial form of exercise that requires
no special equipment (except for proper shoes) and can be performed anywhere.
People with diabetes should discuss an exercise program with their physician
and undergo a careful medical evaluation with appropriate diagnostic studies
before beginning an exercise program (ADA, Physical Activity/Exercise and
Diabetes Mellitus, 2003; Creviston & Quinn, 2001; Flood & Constance,
2002). For patients who are older than 30 years and who have two or more risk
factors for heart disease, an exercise stress test is recommended. Risk factors
for heart disease include hypertension, obesity, high cholesterol levels,
abnormal resting electrocardiogram, sedentary lifestyle, smoking, male gender,
and a family history of heart disease.
Gerontologic
Considerations
Physical activity
that is consistent and realistic is beneficial to the elderly person with
diabetes. Physical fitness in the elderly population with diabetes may lead to
less chronic vascular disease and an improved quality of life (ADA, Physical
Activity/Exercise and Diabetes Mellitus, 2003). Advantages of exercise in this
population include a decrease in hyperglycemia, a general sense of wellbeing,
and the use of ingested calories, resulting in weight reduction. Because there
is an increased incidence of cardiovascular problems in the elderly, a pattern
of gradual, consistent exercise should be planned that does not exceed the
patient’s physical capacity. Physical impairment from other chronic diseases
must also be considered. In some cases a physical therapy evaluation may be
warranted with the goal of determining exercises specific to the patient’s
needs and abilities. Tools such as the “Armchair Fitness” video may be helpful.
For more information about agerelated changes that affect diabetes management
see Chart 41-6.
MONITORING GLUCOSE LEVELS AND KETONES
Blood glucose
monitoring is a cornerstone of diabetes management, and self-monitoring of
blood glucose (SMBG) levels by patients has dramatically altered diabetes
care. Frequent SMBG enables people with diabetes to adjust the treatment
regimen to obtain optimal blood glucose control. This allows for detection and
prevention of hypoglycemia and hyperglycemia and plays a crucial role in
normalizing blood glucose levels, which in turn may reduce the risk of
long-term diabetic complications. Various SMBG methods are available. Most
involve obtaining a drop of blood from the fingertip, applying the blood to a
special reagent strip, and allowing the blood to stay on the strip for the
amount of time specified by the manufacturer (usually 5 to 30 seconds). The
meter gives a digital readout of the blood glucose value.
The meters
available for SMBG offer different features and benefits. Newer monitors have
eliminated the step of blood removal from the strip. The strip is placed in the
meter first, before blood is applied to it. Once the blood is placed on the
strip, it remains there for the duration of the test. The meter automatically
displays the blood glucose level after a short time (less than 1 minute). Some
meters are biosensors that use blood obtained from alternate test sites, such
as the forearm. They have a special lancing device that is useful for patients
who have painful fingertips or pain with finger sticks. Some meters can be used
by patients with visual impairments. They have audio components that assist the
patient in performing the test and obtaining the result. In addition, meters
are available to check both blood glucose and blood ketone levels by those who
are particularly susceptible to development of DKA.
Advantages and
Disadvantages of SMBG Systems
The monitoring
method used by the patient must match his or her skill level. Factors affecting
SMBG performance include visual acuity, fine motor coordination, cognitive
ability, comfort with technology, willingness, and cost. Visual methods are the
least expensive and require less equipment. However, they require the ability
to distinguish colors and to be exact in timing the procedures. Further, they
involve subjective interpretation of results. Monitoring blood glucose using
meters is recommended because meters have become much less expensive and less
technique-dependent, making the results more accurate. Referral to a social
worker may be warranted to assist individuals without the financial means to
purchase a meter. Older meters that required removal of blood from the reagent
strip are generally obsolete. These procedures have more steps that must be
performed in an exact sequence. The newer meters that do not require removal of
blood from the strip generally are easier to use. However, most do not provide
a backup method for visually assessing the meter results. Figure 41-3
illustrates a system for glucose monitoring. A potential hazard of all SMBG
methods is that the patient may obtain and report erroneous blood glucose
values as a result of using incorrect techniques.
Some common
sources of error include:
• Improper application of blood (eg, drop too small)
• Improper meter cleaning and maintenance (eg, allowing
dust or blood to accumulate on the optic window). This is not an issue in the
biosensor type of meter.
• Damage to the reagent strips by heat or humidity; use
of outdated strips
The nurse plays an important role in providing
initial teaching about SMBG techniques. Equally important is evaluating the
techniques of patients who are experienced in self-monitoring. Patients should
be discouraged from purchasing SMBG products from stores or catalogs that do
not provide direct education. Every 6 to 12 months, patients should conduct a
comparison of their meter with a simultaneous laboratory-measured blood glucose
level in their physician’s office. The accuracy of the meter and strips should
also be assessed with control solutions specific to that meter whenever a new
vial of strips is used or whenever the validity of the reading is in doubt.
Candidates for SMBG
For everyone with
diabetes, SMBG is useful for managing selfcare. It is a key component of treatment
for any intensive insulin therapy regimen (including two to four injections per
day or insulin pumps) and for diabetes management during pregnancy. It is also
recommended for patients with: • Unstable diabetes • A tendency for
severe ketosis or hypoglycemia • Hypoglycemia without warning symptoms For patients not
taking insulin, SMBG is helpful for monitoring the effectiveness of exercise,
diet, and oral antidiabetic agents. It can also help motivate patients to
continue with treatment. For patients with type 2 diabetes, SMBG is recommended
during periods of suspected hyperglycemia (eg, illness) or hypoglycemia (eg,
unusual increased activity levels) (ADA, Physical Activity/Exercise and
Diabetes Mellitus, 2003).
Frequency of SMBG
For most patients
who require insulin, SMBG is recommended two to four times daily (usually
before meals and at bedtime). For patients who take insulin before each meal,
SMBG is required at least three times daily before meals to determine each dose
(ADA, Tests of Glycemia in Diabetes, 2002). Patients not receiving insulin may
be instructed to assess their blood glucose levels at least two or three times
per week, including a 2-hour postprandial test. For all patients, testing is
recommended whenever hypoglycemia or hyperglycemia is suspected. The patient
should increase the frequency of SMBG with changes in medications, activity, or
diet and with stress or illness.
Responding to SMBG
Results
Patients are
instructed to keep a record or logbook of blood glucose levels so that they can
detect patterns. Testing is done at the peak action time of the medication to
evaluate the need for dosage adjustments. To evaluate basal insulin and
determine bolus insulin doses, testing is performed before meals. To titrate
bolus insulin doses, regular or lispro, testing is done 2 hours after meals.
Patients with type 2 diabetes are encouraged to test before and 2 hours after
the largest meal of the day. Patients who take insulin at bedtime or who are on
an insulin infusion pump must also test at
Glycosylated
Hemoglobin
Glycosylated
hemoglobin (referred to as
HgbA1C or A1C) is a blood test that reflects average blood glucose levels over
a period of approximately 2 to 3 months (
Urine Testing for
Glucose
Before SMBG methods
were available, urine glucose testing was the only way to monitor diabetes on a
daily basis. Today its use is limited to patients who cannot or will not
perform SMBG. The advantages of urine glucose testing are that it is less
expensive than SMBG and it is not invasive. The general procedure involves
applying urine to a reagent strip or tablet and matching colors on the strip
with a color chart at the end of a specified period.
Disadvantages of
urine testing include the following:
• Results do not accurately reflect the blood glucose
level at the time of the test.
• The renal threshold for glucose is 180 to 200 mg/dL
(9.9 to 11.1 mmol/L), far above target blood glucose levels.
• Hypoglycemia cannot be detected because a “negative”
urine glucose result may occur when the blood glucose level ranges from 0 to
180 mg/dL (9.9 mmol/L) or higher.
• Patients may have a false sense of being in good
control when results are always negative.
• Various medications (eg, aspirin, vitamin C, some
antibiotics) may interfere with test results.
• In elderly patients and patients with kidney disease,
the renal threshold (the level of blood glucose at which glucose starts to
appear in the urine) is raised; thus, false-negative readings may occur at dangerously
elevated glucose levels.
Testing for Ketones
Ketones (or ketone
bodies) in the urine signal that control of type 1 diabetes is deteriorating,
and the risk of DKA is high. When there is almost no effective insulin
available, the body starts to break down stored fat for energy. Ketone bodies
are byproducts of this fat breakdown, and they accumulate in the blood and
urine. Urine testing is the most common method used for self-testing of ketone
bodies by patients. A meter that enables testing of blood for ketones is
available but not widely used. Most commonly, patients use a urine dipstick
(Ketostix or Chemstrip uK) to detect ketonuria. The reagent pad on the strip
turns purplish when ketones are present. (One of the ketone bodies is called
acetone, and this term is frequently used interchangeably with the term
“ketones.”) Other strips are available for measuring both urine glucose and
ketones (Keto-Diastix or Chemstrip uGK). Large amounts of ketones may depress
the color response of the glucose test area. Urine ketone testing should be
performed whenever patients with type 1 diabetes have glucosuria or
persistently elevated blood glucose levels (more than 240 mg/dL or 13.2 mmol/L
for two testing periods in a row) and during illness, in pregnancy with
pre-existing diabetes, and in gestational diabetes (ADA, Tests of Glycemia in
Diabetes, 2003).
PHARMACOLOGIC
THERAPY
As stated earlier,
insulin is secreted by the beta cells of the islets of Langerhans and works to
lower the blood glucose level after meals by facilitating the uptake and
utilization of glucose by muscle, fat, and liver cells. In the absence of
adequate insulin, pharmacologic therapy is essential.
Insulin Therapy and
Insulin Preparations
Because the body loses
the ability to produce insulin in type 1 diabetes,
exogenous insulin must be administered for life. In type 2 diabetes, insulin
may be necessary on a long-term basis to control glucose levels if diet and
oral agents fail. In addition, some patients in whom type 2 diabetes is usually
controlled by diet alone or by diet and an oral agent may require insulin
temporarily during illness, infection, pregnancy, surgery, or some other
stressful event. In many cases, insulin injections are administered two or more
times daily to control the blood glucose level. Because the insulin dose
required by the individual patient is determined by the level of glucose in the
blood, accurate monitoring of blood glucose levels is essential; thus, SMBG has
become a cornerstone of insulin therapy. A number of insulin preparations are
available. They vary according to three main characteristics: time course of
action, species (source), and manufacturer.
TIME COURSE OF
ACTION
Insulin may be
grouped into several categories based on the onset, peak, and duration of
action. Human insulin preparations have a shorter duration of action than
insulin from animal sources because the presence of animal proteins triggers an
immune response that results in the binding of animal insulin, which slows its
availability. Rapid-acting insulins such as insulin lispro (Humalog) and
insulin aspart (Novolog) are blood glucose-lowering agents that produce a more
rapid effect that is of shorter duration than regular insulin. These insulins
have an onset of 5 to 15 minutes, a peak action of 1 hour after injection, and
a duration of 2 to 4 hours. Because of their rapid onset, patients should be
instructed to eat no more than 5 to 15 minutes after injection. Because of the
short duration of action of these insulin analogs, patients with type 1
diabetes and some patients with type 2 or gestational diabetes also require a
long-acting insulin to maintain glucose control. Basal insulin is necessary to
maintain blood glucose levels irrespective of meals. A constant level of
insulin is required at all times. Intermediate-acting insulins function as
basal insulins but may have to be split into two injections to achieve 24-hour
coverage. Short-acting insulins, called regular insulin (marked R on the
bottle), have an onset of 30 minutes to 1 hour; peak, 2 to 3 hours; and
duration, 4 to 6 hours. Regular insulin is a clear solution and is usually
administered 20 to 30 minutes before a meal, either alone or in combination
with a longer-acting insulin. Humulin R, Iletin Regular, and Novolin R are
examples of regular insulin. Intermediate-acting insulins, called NPH insulin
(neutral protamine Hagedorn) or Lente insulin, have an onset of 3 to 4 hours;
peak, 4 to 12 hours; and duration, 16 to 20 hours. Intermediateacting insulins,
which are similar in their time course of action, appear white and cloudy. If
NPH or Lente insulin is taken alone, it is not crucial that it be taken 30
minutes before the meal. It is important, however, for the patient to eat some
food around the time of the onset and peak of these insulins. Humulin N, Iletin
NPH, and Novolin N are examples of NPH insulins; Humulin L, Iletin L, and
Novolin L are examples of Lente insulins. Long-acting insulins, called
Ultralente insulin, are sometimes referred to as peakless insulins because they
tend to have a long, slow, sustained action rather than sharp, definite peaks
in action. The onset of long-acting human insulin is 6 to 8 hours; peak, 12 to
16 hours; and duration, 20 to 30 hours. “Peakless” basal insulin, insulin
glargine (Lantus), is approved for use as a basal insulin—that is, the insulin
is absorbed very slowly over 24 hours and can be given once a day. Because the
insulin is in a suspension with a pH of 4, it cannot be mixed with other
insulins because this would cause precipitation. It is given once a day at
bedtime. In the future, “inhaled insulin” may be approved for use. This type of
insulin is in the form of a very fine powder, which is inhaled through a device
similar to that used to administer asthma medications. The patient’s program
would consist of a “basal” rate of insulin such as glargine supplemented by an
inhaled dose before each meal. The nurse may find that different sources list
differing numbers of hours for the onset, peak, and duration of action of the
main types of insulin, and patients’ responses may vary (ie, larger doses
prolong onset, duration, and peak). The nurse should focus on which meals—and
snacks—are being “covered” by which insulin doses. In general, the rapid- and
short-acting insulins are expected to cover the rise in glucose levels after
meals, immediately after the injection; the intermediate-acting insulins are
expected to cover subsequent meals; and the long-acting insulins provide a
relatively constant level of insulin and act as a basal insulin.
SPECIES (SOURCE)
In the past, all
insulins were obtained from beef (cow) and pork (pig) pancreases. “Human
insulins” are now widely available. They are produced by recombinant DNA
technology and have largely replaced insulin from animal sources (ADA, Insulin
Administration, 2003).
MANUFACTURER
The two
manufacturers of insulin in the
Insulin Regimens
Insulin regimens
vary from one to four injections per day. Usually there is a combination of a
short-acting insulin and a longeracting insulin. The normally functioning
pancreas continuously secretes small amounts of insulin during the day and
night. In addition, whenever blood glucose rises after ingestion of food, there
is a rapid burst of insulin secretion in proportion to the glucoseraising
effect of the food. The goal of all but the simplest, oneinjection insulin
regimens is to mimic this normal pattern of insulin secretion in response to
food intake and activity patterns.
Patients can learn
to use SMBG results and carbohydrate counting to vary the insulin doses. This
allows patients more flexibility in the timing and content of meals and
exercise periods. However, complex insulin regimens require a strong level of
commitment, intensive education, and close follow-up by the health care team.
In addition, patients aiming for normal blood glucose levels run the risk of
more hypoglycemic reactions. The type of regimen used by any particular patient
varies. For example, patient knowledge, willingness, goals, health status, and
finances all may affect decisions regarding insulin treatment. In addition, the
physician’s philosophy about blood glucose control and the availability of
equipment and support staff may influence decisions regarding insulin therapy.
There are two general approaches to insulin therapy: conventional and
intensive.
CONVENTIONAL
REGIMEN
One approach is to
simplify the insulin regimen as much as possible, with the aim of avoiding the
acute complications of diabetes (hypoglycemia and symptomatic hyperglycemia).
With this type of simplified regimen (eg, one or more injections of a mixture
of short- and intermediate-acting insulins per day), patients may frequently
have blood glucose levels well above normal. The exception is the patient who
never varies meal patterns and activity levels. This approach would be
appropriate for the terminally ill, the frail elderly with limited self-care
abilities, or any patient who is completely unwilling or unable to engage in
the self-management activities that are part of a more complex insulin regimen.
INTENSIVE
REGIMEN
The second
approach is to use a more complex insulin regimen to achieve as much control
over blood glucose levels as is safe and practical. The results of the landmark
DCCT study (1993) and the UKPDS study (1998) have demonstrated that maintaining
blood glucose levels as close to normal as possible prevents or slows the progression
of long-term diabetic complications. Another reason for using a more complex
insulin regimen is to allow patients more flexibility to change their insulin
doses from day to day in accordance with changes in their eating and activity
patterns, with stress and illness, and as needed for variations in the
prevailing glucose level. Although the DCCT found that intensive treatment
(three or four injections of insulin per day) reduced the risk of
complications, not all people with diabetes are candidates for very tight
control of blood glucose. The risk for severe hypoglycemia was increased
threefold in patients receiving intensive treatment in the DCCT (
Those who may not
be candidates include patients with:
• Nervous system disorders rendering them unaware of
hypoglycemic episodes (eg, those with autonomic neuropathy)
• Recurring severe hypoglycemia
• Irreversible diabetic complications, such as blindness
or end-stage renal disease
• Cerebrovascular and/or cardiovascular disease
• Ineffective self-care skills
An exception is
the patient who has received a kidney transplant because of nephropathy and
chronic renal failure; this patient should be on an intensive regimen to preserve
function of the new kidney. The patient needs to be involved in the decision
regarding which insulin regimen to use. Patients need to compare the potential
benefits of different regimens with the potential costs (eg, time involved,
number of injections or finger sticks for glucose testing, amount of
record-keeping). There are no set guidelines as to which insulin regimen should
be used for which patients. It must not be assumed that an elderly patient or a
patient with visual impairment should automatically be given a simplified
regimen. Likewise, it must not be assumed that all people will want to be
involved in a complex treatment regimen. Nurses play an important role in
educating patients about the different approaches to insulin therapy. Nurses
should refer patients to diabetes specialists or diabetes education centers,
when available, for further training and education in the various insulin
treatment regimens.
Complications of
Insulin Therapy
LOCAL ALLERGIC
REACTIONS
A local allergic
reaction (redness, swelling, tenderness, and induration or a 2- to 4-cm wheal)
may appear at the injection site 1 to 2 hours after the insulin administration.
These reactions, which usually occur during the beginning stages of therapy and
disappear with continued use of insulin, are becoming rare because of the
increased use of human insulins. The physician may prescribe an antihistamine
to be taken 1 hour before the injection if such a local reaction occurs.
SYSTEMIC ALLERGIC
REACTIONS
Systemic allergic
reactions to insulin are rare. When they do occur, there is an immediate local
skin reaction that gradually spreads into generalized urticaria (hives). The
treatment is desensitization, with small doses of insulin administered in
gradually increasing amounts using a desensitization kit. These rare reactions
are occasionally associated with generalized edema or anaphylaxis.
INSULIN
LIPODYSTROPHY
Lipodystrophy
refers to a localized reaction, in the form of either lipoatrophy or
lipohypertrophy, occurring at the site of insulin injections. Lipoatrophy is
loss of subcutaneous fat and appears as slight dimpling or more serious pitting
of subcutaneous fat. The use of human insulin has almost eliminated this
disfiguring complication. Lipohypertrophy, the development of fibrofatty masses
at the injection site, is caused by the repeated use of an injection site. If
insulin is injected into scarred areas, absorption may be delayed.
This is one reason
that rotation of injection sites is so important. The patient should avoid
injecting insulin into these areas until the hypertrophy disappears.
INSULIN RESISTANCE
Most patients at
one time or another have some degree of insulin resistance. This may occur for
various reasons, the most common being obesity, which can be overcome by weight
loss. Clinical insulin resistance has been defined as a daily insulin
requirement of 200 units or more. In most diabetic patients taking insulin,
immune antibodies develop and bind the insulin, thereby decreasing the insulin
available for use. All animal insulins, as well as human insulins to a lesser
degree, cause antibody production in humans. Very few resistant patients
develop high levels of antibodies. Many of these patients have a history of
insulin therapy interrupted for several months or more. Treatment consists of
administering a more concentrated insulin preparation, such as U500, which is
available by special order. Occasionally, prednisone is needed to block the
production of antibodies. This may be followed by a gradual reduction in
insulin requirement. Therefore, patients need to monitor themselves for
hypoglycemia.
MORNING
HYPERGLYCEMIA
An elevated blood
glucose level upon arising in the morning may be caused by an insufficient
level of insulin due to several causes: the dawn phenomenon, the Somogyi
effect, or insulin waning. The dawn phenomenon is characterized by a relatively
normal blood glucose level until approximately
Alternative Methods
of Insulin Delivery
INSULIN PENS
These devices use
small (150- to 300-unit) prefilled insulin cartridges that are loaded into a
penlike holder. A disposable needle is attached to the device for insulin
injection. Insulin is delivered by dialing in a dose or pushing a button for
every 1- or 2-unit increment administered. People using these devices still
need to insert the needle for each injection; however, they do not need to
carry insulin bottles or to draw up insulin before each injection. These
devices are most useful for patients who need to inject only one type of
insulin at a time (eg, premeal regular insulin three times a day and bedtime
NPH insulin) or who can use the premixed insulins. These pens are convenient
for those who administer insulin before dinner if eating out or traveling. They
are also useful for patients with impaired manual dexterity, vision, or
cognitive function that makes the use of traditional syringes difficult.
JET INJECTORS
As an alternative
to needle injections, jet injection devices deliver insulin through the skin
under pressure in an extremely fine stream. These devices are more expensive
than other alternative devices mentioned above and require thorough training
and supervision when first used. In addition, patients should be cautioned that
absorption rates, peak insulin activity, and insulin levels may be different
when changing to a jet injector. (Insulin administered by jet injector is
usually absorbed faster.) Bruising has occurred in some patients with use of
the jet injector.
INSULIN PUMPS
Continuous
subcutaneous insulin infusion involves the use of small, externally worn devices that closely mimic the
functioning of the normal pancreas (
IMPLANTABLE AND
INHALANT INSULIN DELIVERY
Research into
mechanical delivery of insulin has involved implantable insulin pumps that can
be externally programmed according to blood glucose test results. Clinical
trials with these devices are continuing. In addition, there is research into
the development of implantable devices that both measure the blood glucose
level and deliver insulin as needed. Methods of administering insulin by the
oral route (oral spray or capsule), skin patch, and inhalation are undergoing
intensive study.
TRANSPLANTATION OF
PANCREATIC CELLS
Transplantation of
the whole pancreas or a segment of the pancreas is being performed on a limited
population (mostly diabetic patients receiving kidney transplantations
simultaneously). One main issue regarding pancreatic transplantation is
weighing the risks of antirejection medications against the advantages of
pancreas transplantation. Another approach under investigation is the
implantation of insulin-producing pancreatic islet cells (ADA, Pancreas
Transplantation for Patients With Type 1 Diabetes, 2003). This latter approach
involves a less extensive surgical procedure and a potentially lower incidence
of immunogenic problems. However, thus far, independence from exogenous insulin
has been limited to 2 years after transplantation of islet cells. A recent
study of patients with islet cell transplants using less toxic
antirejection drugs has shown promise (Shapiro et al., 2000).
Oral Antidiabetic
Agents
Oral antidiabetic
agents may be effective for patients who have type 2 diabetes
that cannot be treated by diet and exercise alone; however, they cannot be used
during pregnancy. In the United States, oral antidiabetic agents include
the sulfonylureas, biguanides, alpha glucosidase inhibitors,
thiazolidinediones, and meglitinides (Table 41-6). Sulfonylureas and meglitinides
are considered insulin secretagogues because their action increases the
secretion of insulin by the pancreatic beta cells.
SULFONYLUREAS
The sulfonylureas
exert their primary action by directly stimulating the pancreas to secrete
insulin. Therefore, a functioning pancreas is necessary for these agents to be
effective, and they cannot be used in patients with type 1 diabetes. These
agents improve insulin action at the cellular level and may also directly
decrease glucose production by the liver. The sulfonylureas can be divided into
first- and second-generation categories (see Table 41-6). The most common side
effects of these medications are GI symptoms and dermatologic reactions.
Hypoglycemia may occur when an excessive dose of a sulfonylurea is used or when
the patient omits or delays meals, reduces food intake, or increases activity.
Because of the prolonged hypoglycemic effects of these agents (especially
chlorpropamide), some patients need to be hospitalized for treatment of oral
agent-induced hypoglycemia. Another side effect of chlorpropamide is a
disulfiram (Antabuse) type of reaction when alcohol is ingested (see section on
alcohol consumption for more information). Some medications may directly
interact with sulfonylureas, potentiating their hypoglycemic effects (eg,
sulfonamides, chloramphenicol, clofibrate, phenylbutazone, and
bishydroxycoumarin). In addition, certain medications may independently affect
blood glucose levels, thereby indirectly interfering with these agents.
Medications that may increase glucose levels include potassium-losing
diuretics, corticosteroids, estrogen compounds, and diphenylhydantoin
(Dilantin). Medications that may cause hypoglycemia include salicylates,
propranolol, monoamine oxidase inhibitors, and pentamidine. Second-generation
sulfonylureas have the advantage of a shorter half-life and excretion by both
the kidney and the liver. This makes these medications safer to use in the
elderly, in whom accumulation of the medication can cause recurring
hypoglycemia.
BIGUANIDES
The biguanides are
other kinds of oral antidiabetic agents. Metformin (Glucophage) produces its
antidiabetic effects by facilitating insulin’s action on peripheral receptor sites.
Therefore, it can be used only in the presence of insulin. Biguanides have no
effect on pancreatic beta cells. Biguanides used with a sulfonylurea may
enhance the glucose-lowering effect more than either medication used alone.
Lactic acidosis is a potential and serious complication of biguanide therapy;
the patient must be monitored closely when therapy is initiated or when dosage
changes. Medications that may interact with biguanides include anticoagulants,
corticosteroids, diuretics, and oral contraceptives. Metformin is
contraindicated in patients with renal impairment (serum creatinine level more
than 1.4) or those at risk for renal dysfunction (eg, those with acute
myocardial infarction). Renal function studies should be performed periodically
to ensure that function is not impaired. Metformin should not be administered
for 2 days before any diagnostic testing that may require use of a contrast
agent. These situations increase the risk for lactic acidosis. An
extended-release form and a combination form (Glucovance) combines metformin
with a sulfonylurea, such as glyburide. The combination provides two mechanisms
of action and improved patient compliance. Hypoglycemia is a risk.
ALPHA
GLUCOSIDASE INHIBITORS
Acarbose (Precose)
and miglitol (Glyset) are oral alpha glucosidase inhibitors used in type
2 diabetes management. They work by delaying the absorption of glucose in the
intestinal system, resulting in a lower postprandial blood glucose level. As a
consequence of plasma glucose reduction, hemoglobin A1C levels drop. In
contrast to the sulfonylureas, acarbose and miglitol do not enhance insulin
secretion. They can be used alone with dietary treatment as monotherapy or in
combination with sulfonylureas, thiazolidinediones, or meglitinides. When these
medications are used in combination with sulfonylureas or meglitinides,
hypoglycemia may occur. The patient must be advised that if hypoglycemia
occurs, sucrose absorption will be blocked and treatment for hypoglycemia
should be in the form of glucose, such as glucose tablets. The advantage of
oral alpha glucosidase inhibitors is that they are not systemically absorbed
and are safe to use. Their side effects are diarrhea and flatulence. These
effects may be minimized by starting at a very low dose and increasing the dose
gradually. Because acarbose and miglitol affect food absorption, they must be
taken immediately before a meal, making therapeutic adherence a potential
problem.
THIAZOLIDINEDIONES
Rosiglitizone
(Avandia) and pioglitozone (Actos) are oral diabetes medications categorized as
thiazolidinediones. They are indicated for patients with type 2 diabetes
who take insulin injections and whose blood glucose control is inadequate
(hemoglobin A1C level greater than 8.5%). They have also been approved as
firstline agents to treat type 2 diabetes, in combination with diet.
Thiazolidinediones enhance insulin action at the receptor site without
increasing insulin secretion from the beta cells of the pancreas. These
medications may affect liver function; therefore, liver function studies must
be performed at baseline and at frequent intervals (monthly for the first 12
months of treatment, and quarterly thereafter). Women should be informed that
thiazolidinediones can cause resumption of ovulation in perimenopausal
anovulatory women, making pregnancy a possibility.
MEGLITINIDES
Repaglinide
(Prandin), an oral glucose-lowering agent of the class of oral agents called
meglitinides, lowers the blood glucose level by stimulating insulin release
from the pancreatic beta cells. Its effectiveness depends on the presence of
functioning beta cells. Therefore, repaglinide is contraindicated in patients
with type 1 diabetes. Repaglinide has a fast action and a short duration. It
should be taken before each meal to stimulate the release of insulin in
response to that meal. It is also indicated for use in combination with
metformin in patients whose hyperglycemia cannot be controlled by exercise,
diet, and either metformin or repaglinide alone. The principal side effect of
repaglinide is hypoglycemia; however, this side effect is less severe and
frequent than for a sulfonylurea because repaglinide has a short half-life
(approximately 1 hour). Patients must be taught the signs and symptoms of
hypoglycemia and should understand that the medication should not be taken
unless the patient eats a meal. Repaglinide is supplied in 0.5-, 1-, and 2-mg
tablets. Naglitinide (Starlix), another meglitinide, has a very rapid onset and
short duration. It should be taken with meals and not taken if the meal is
skipped. Hypoglycemia risk is low if taken correctly.
General
Considerations for Oral Agents
Patients need to
understand that oral agents are prescribed as an addition to (not as a
substitute for) other treatment modalities, such as diet and exercise. Use of
oral antidiabetic medications may need to be halted temporarily and insulin
prescribed if hyperglycemia develops that is attributable to infection, trauma,
or surgery. In time, oral antidiabetic agents may no longer be effective in
controlling the patient’s diabetes. In such cases, the patient is treated with
insulin. Approximately half of all patients who initially use oral antidiabetic
agents eventually require insulin. This is referred to as a secondary failure.
Primary failure occurs when the blood glucose level remains high a month after
initial medication use. Because the mechanisms of action vary (Fig. 41-6), the
effect may be enhanced using multidose, multiple medications (Inzucchi et al.,
1998). Use of multiple medications with different mechanisms of action is very
common today (Quinn, 2001b). Using a combination of oral agents with insulin
has been proposed as a treatment for some patients with type 2 diabetes.
However, the effectiveness of this approach has not yet been demonstrated. Nursing Management Nursing management of the patient with diabetes can
involve treatment of a wide variety of physiologic disorders, depending on the
patient’s health status and whether the patient is newly diagnosed or seeks
care for an unrelated health problem. Nursing management of the newly diagnosed
patient and the patient with diabetes as a secondary diagnosis is presented in
subsequent sections of this chapter. Because all diabetic patients must master
the concepts and skills necessary for long-term management of diabetes and its
potential complications, a solid educational foundation is necessary for
competent self-care and is an ongoing focus of nursing care.
EDUCATION
Diabetes mellitus
is a chronic illness requiring a lifetime of special self-management behaviors.
Because diet, physical activity, and physical and emotional stress affect
diabetic control, patients must learn to balance a multitude of factors. They
must learn daily self-care skills to prevent acute fluctuations in blood glucose,
and they must also incorporate into their lifestyle many preventive behaviors
for avoidance of long-term diabetic complications. Diabetic patients must
become knowledgeable about nutrition, medication effects and side effects,
exercise, disease progression, prevention strategies, blood glucose monitoring
techniques, and medication adjustment. In addition, they must learn the skills
associated with monitoring and managing diabetes and must incorporate many new
activities into their daily routines. An appreciation for the knowledge and
skills that diabetic patients must acquire can help the nurse in providing
effective patient education and counseling (Beebe & O’Donnell, 2001).
DEVELOPING A
DIABETIC TEACHING PLAN
Changes in the
health care delivery system as a whole have had a major impact on diabetes
education and training. Patients with new-onset type 1 diabetes have much
shorter hospital stays or may be managed completely on an outpatient basis;
patients with new-onset type 2 diabetes are rarely hospitalized for initial
care. There has been a proliferation of outpatient diabetes education and
training programs, with increasing support of third-party reimbursement. For
some patients, however, exposure to diabetes education during hospitalization may
be the only opportunity for learning self-management skills and preventing
complications. Many hospitals employ nurses who specialize in diabetes
education and management and who are certified by the National Certification
Board of Diabetes Educators as Certified Diabetes Educators. However, because
of the large number of diabetic patients who are admitted to every unit of a
hospital for reasons other than diabetes or its complications, the staff nurse
plays a vital role in identifying diabetic patients, assessing self-care
skills, providing basic education, reinforcing the teaching provided by the
specialist, and referring patients for follow-up care after discharge. Diabetes
patient education programs that have been peerreviewed by the ADA as meeting National
Standards for Diabetes Education can seek reimbursement for education.
Organizing
Information
There are various
strategies for organizing and prioritizing the vast amount of information that
must be taught to diabetic patients. In addition, many hospitals and outpatient
diabetes centers have devised written guidelines, care plans, and documentation
forms (often based on guidelines from the ADA) that may be used to document and
evaluate teaching. A general approach is to organize information and skills
into two main types: basic, initial, or “survival” skills and information, and
in-depth (advanced) or continuing education.
TEACHING SURVIVAL
SKILLS
This information
must be taught to any patient with newly diagnosed type 1 or type 2 diabetes and any patient receiving insulin for the first
time. This basic information is literally what the patient must know to
survive—that is, to avoid severe hypoglycemic or acute hyperglycemic
complications after discharge. An outline of survival information includes: 1.
Simple pathophysiology a. Basic definition of diabetes (having a high blood
glucose level) b. Normal blood glucose ranges and target blood glucose levels
c. Effect of insulin and exercise (decrease glucose) d. Effect of food and
stress, including illness and infections (increase glucose) e. Basic treatment
approaches 2. Treatment modalities a. Administration of insulin and oral
antidiabetes medications b. Diet information (food groups, timing of meals) c.
Monitoring of blood glucose and ketones 3. Recognition, treatment, and
prevention of acute complications a. Hypoglycemia b. Hyperglycemia 4. Pragmatic
information a. Where to buy and store insulin, syringes, and glucose monitoring
supplies b. When and how to reach the physician For patients with newly diagnosed
type 2 diabetes, emphasis is initially placed on diet. Patients starting to
take oral sulfonylureas or meglitinides need to know about detecting,
preventing, and treating hypoglycemia. If diabetes has gone undetected for many
years, the patient may already be experiencing some chronic diabetic
complications. Thus, for some patients with newly diagnosed type 2 diabetes,
the basic diabetes teaching must include information on preventive skills, such
as foot care and eye care—for example, planning yearly or more frequent
complete (dilated eye) examinations by the ophthalmologist and understanding
that retinopathy is largely asymptomatic until the advanced stages. Patients
also need to realize that once they master the basic skills and information,
further diabetes education must be pursued. Acquiring in-depth and advanced
diabetes knowledge occurs throughout the patient’s lifetime, both formally
through programs of continuing education and informally through experience and
sharing of information with other people with diabetes.
PLANNING IN-DEPTH
AND CONTINUING EDUCATION
This involves
teaching more detailed information related to survival skills (eg, learning to
vary diet and insulin and preparing for travel) as well as learning preventive
measures for avoiding longterm diabetic complications.
Preventive
measures include:
• Foot care
• Eye care
• General hygiene (eg, skin care, oral hygiene)
• Risk factor management (eg, control of blood pressure
and blood lipid levels, and normalizing blood glucose levels)
More advanced
continuing education may include alternative methods for insulin delivery, such
as the insulin pump, and algorithms or rules for evaluating and adjusting
insulin doses. For example, patients can be taught to increase or decrease insulin
doses based on a several-day pattern of blood glucose levels. The degree of
advanced diabetes education to be provided depends on the patient’s interest
and ability. However, learning preventive measures (especially foot care and
eye care) is mandatory for reducing the occurrence of amputations and blindness
in diabetic patients.
Assessing Readiness
to Learn
Before initiating
diabetes education, the nurse assesses the patient’s (and family’s) readiness
to learn (Beebe & O’Donnell, 2001). When patients
are first diagnosed with diabetes (or first told of their need for insulin),
they often go through various stages of the grieving process. These stages may
include shock and denial, anger, depression, negotiation, and acceptance. The
amount of time it takes for patients and family members to work through the
grieving process varies from patient to patient. They may experience
helplessness, guilt, altered body image, loss of self-esteem, and concern about
the future. The nurse must assess the patient’s coping strategies and reassure
patients and families that feelings of depression and shock are normal. Asking
the patient and family about their major concerns or fears is an important way
to learn about any misinformation that may be contributing to anxiety. Some
common misconceptions regarding diabetes and its treatment are listed in Table
41-7. Simple, direct information should be provided to dispel misconceptions.
More information can be provided once the patient masters survival skills.
After dispelling misconceptions or answering questions that concern the patient
the most, the nurse focuses attention on concrete survival skills. Because of
the immediate need for multiple new skills, teaching is initiated as soon as
possible after diagnosis. Nurses whose patients are in the hospital rarely have
the luxury of waiting until the patient feels ready to learn; short hospital
stays necessitate initiation of survival skill education as early as possible.
This gives the patient the opportunity to practice skills with supervision by
the nurse before discharge. Follow-up by home health nurses is often necessary
for reinforcement of survival skills. A major goal of patient teaching is an
educated consumer, a patient who is informed about the wide variations in the
prices of medications and supplies and about the importance of comparing
prices.
Determining
Teaching Methods
Maintaining
flexibility in teaching approaches is important. Teaching skills and
information in a logical sequence is not always the most helpful for patients.
For example, many patients fear the injection. Before they learn how to draw
up, purchase, store, and mix insulins, they should be taught to insert the
needle and inject insulin (or practice with saline solution). Numerous
demonstrations by the nurse or practice injections before the patient (or
family) gives the first injection may actually increase the patient’s anxiety
and fear of self-injection. Once patients have actually performed the
injection, most are more prepared to hear and to comprehend other information.
(If they then want to practice further using a pillow or an orange, that would
be appropriate.) Thus, having patients self-inject first or having patients
perform a fingerstick for glucose monitoring first may enhance learning to draw
up the insulin or to operate the glucose meter. Ample opportunity should be
provided for the patient and family to practice skills under supervision
(including selfinjection, self-testing, meal selection, verbalization of symptoms,
and treatment of hypoglycemia). Once skills have been mastered, participation
in ongoing support groups may assist patients in incorporating new habits and
maintaining adherence to the treatment regimen. Various tools can be used to
complement teaching. Many of the companies that manufacture products for
diabetes self-care also provide booklets and videotapes to assist in patient
teaching. It is important to use a variety of written handouts that match the
patient’s learning needs (including different languages, lowliteracy
information, large print). Patients can continue learning about diabetes care
by participating in activities sponsored by local hospitals and diabetes
organizations. In addition, magazines with information on all aspects of diabetes
management are available for people with diabetes.
IMPLEMENTING THE
PLAN
Teaching
Experienced Diabetic Patients
The nurse should
continue to assess the skills of patients who have had diabetes for many years,
because it is estimated that up to 50% of patients may make errors in
self-care. Assessment of these patients must include direct observation of
skills, not just their self-report of self-care behaviors. In addition, these
patients must be fully aware of preventive measures related to foot care, eye
care, and risk factor management. If patients are experiencing long-term
diabetic complications for the first time, they may go through the grieving
process again. Some of these patients may have a renewed interest in diabetes
self-care in the hope of delaying further complications. Other patients may be
overwhelmed by feelings of guilt and depression. The patient is encouraged to
discuss feelings and fears related to complications; the nurse meanwhile
provides appropriate information regarding diabetic complications.
Teaching Patients
to Self-Administer Insulin
Insulin injections
are administered into the subcutaneous tissue with the use of special insulin
syringes. A variety of syringes and injection-aid devices are available. Chart 41-7
provides important information to include and evaluate when teaching patients
about insulin. Basic information includes explanation of the equipment,
insulins, syringes, and mixing insulin.
STORING INSULIN
Cloudy insulins
should be thoroughly mixed by gently inverting the vial or rolling it between
the hands before drawing the solution into a syringe or a pen. Whether insulin
is the short- or long-acting preparation, the vials not in use should be
refrigerated and extremes of temperature should be avoided; insulin should not
be allowed to freeze and should not be kept in direct sunlight or in a hot car.
The insulin vial in use should be kept at room temperature to reduce local
irritation at the injection site, which may occur when cold insulin is injected.
If a vial of insulin will be used up in 1 month, it may be kept at room
temperature. Patients should be instructed to always have a spare vial of the
type or types of insulin they use (ADA, Insulin Administration, 2003). Spare
vials should be refrigerated. Insulin bottles should also be inspected for
flocculation, which is a frosted, whitish coating inside the bottle of
intermediate- or long-acting insulins. This occurs most commonly with human
insulins that are not refrigerated. If a frosted, adherent coating is present,
some of the insulin is bound and should not be used.
SELECTING SYRINGES
Syringes must be
matched with the insulin concentration (eg, U-100). Currently, three sizes of
U-100 insulin syringes are available:
• 1-mL (cc) syringes that hold 100 units
• 0.5-mL syringes that hold 50 units
• 0.3-mL syringes that hold 30 units
The concentration
of insulin used in the
PREPARING THE
INJECTION: MIXING INSULINS
When rapid- or
short-acting insulins are to be given simultaneously with longer-acting
insulins, they are usually mixed together in the same syringe; the
longer-acting insulins must be mixed thoroughly before use. There is some
question as to whether the two insulins are stable if the mixture is kept in
the syringe for more than 5 to 15 minutes. This may depend on the ratio of the
insulins as well as the time between mixing and injecting. When regular insulin
is mixed with long-acting insulin, there is a binding reaction that slows the action
of the regular insulin. This may also occur to a greater degree when mixing
regular insulin with one of the Lente insulins. Patients are advised to consult
their health care provider for advice on this matter. The most important issue
is that patients be consistent in how they prepare their insulin injections
from day to day. While there are varying opinions regarding which type of
insulin (short- or longer-acting) should be drawn up into the syringe first
when they are going to be mixed, the ADA recommends that the regular insulin be
drawn up first. The most important issues are, again, that patients be
consistent in technique so as not to draw up the wrong dose accidentally or the
wrong type of insulin, and that patients not inject one type of insulin into
the bottle containing a different type of insulin (ADA, Insulin Administration,
2003). For patients who have difficulty mixing insulins, two options are
available: they may use a premixed insulin, or they may have prefilled syringes
prepared. Premixed insulins are available in several different ratios of NPH
insulin to regular insulin. The ratio of 70/30 (70% NPH and 30% regular insulin
in one bottle) is the most common and is available as Novolin 70/30 (Novo
Nordisk) and Humulin 70/30 (Lilly). Other ratios available include 80/20,
60/40, and 50/50. The ratio of 75% NPL and 25% insulin lispro is also available
(ADA, Insulin Administration, 2002). NPL is used only to mix with Humalog; its
action is the same as NPH. The appropriate initial dosage of premixed insulin
must be calculated so that the ratio of NPH to regular insulin most closely
approximates the separate doses needed. For patients who can inject insulin but
who have difficulty drawing up a single or mixed dose, syringes can be
prefilled with the help of home care nurses or family and friends. A 3-week
sup- ply of insulin syringes may be prepared and kept in the refrigerator. The
prefilled syringes should be stored with the needle in an upright position to
avoid clogging of the needle (ADA, Insulin Administration, 2003).
WITHDRAWING INSULIN
Most (if not all)
of the printed materials available on insulin dose preparation instruct
patients to inject air into the bottle of insulin equivalent to the number of
units of insulin to be withdrawn. The rationale for this is to prevent the
formation of a vacuum inside the bottle, which would make it difficult to
withdraw the proper amount of insulin. Some nurses who specialize in diabetes
report that some patients (who have been taking insulin for many years) have
stopped injecting air before withdrawing the insulin. These patients found that
the extra step was not necessary for accurately drawing up the insulin dose.
Most patients find it easier to withdraw the insulin by eliminating the step
and report no difficulty in preparing the proper insulin dose. Eliminating this
step (or alternating it by, for instance, injecting a syringe full of air into
the vial once per week) facilitates the teaching process for some patients
learning to draw up insulin for the first time. Some patients become confused
with the sequence of steps involved in injecting air into two separate bottles
in two different amounts before drawing up a mixed dose. For many individuals,
including elderly ones, simplifying the procedure for preparing insulin
injections may help them maintain independence in daily living. As with other
variations in insulin injection technique, the most important factors are that
the patient maintain consistency in the procedure and that the nurse be flexible
when teaching new patients or assessing the skills of experienced patients.
SELECTING AND
ROTATING THE INJECTION SITE
The four main
areas for injection are the abdomen, arms (posterior surface), thighs (anterior
surface), and hips (Fig. 41-7). Insulin is absorbed faster in some areas of the
body than others. The speed of absorption is greatest in the abdomen and
decreases progressively in the arm, thigh, and hip. Systematic rotation of
injection sites within an anatomic area is recommended to prevent localized
changes in fatty tissue (lipodystrophy). In addition, to promote consistency in
insulin absorption, patients should be encouraged to use all available
injection sites within one area rather than randomly rotating sites from area
to area (ADA, Insulin Administration, 2002). For example, some patients almost
exclusively use the abdominal area, administering each injection 0.5 to
PREPARING THE SKIN
Use of alcohol to
cleanse the skin is not recommended, but patients who have learned this
technique often continue to use it. They should be cautioned to allow the skin
to dry after cleansing with alcohol. If the skin is not allowed to dry before
the injection, the alcohol may be carried into the tissues, resulting in a
localized reddened area.
INSERTING THE
NEEDLE
There are varying
approaches to inserting the needle for insulin injections. The correct
technique is based on the need for the insulin to be injected into the
subcutaneous tissue. Injection that is too deep (eg, intramuscular) or too
shallow may affect the rate of absorption of the insulin. Aspiration (inserting
the needle and then pulling back on the plunger to assess for blood being drawn
into the syringe) is generally not recommended with self-injection of insulin.
Many patients who have been using insulin for an extended period have
eliminated this step from their insulin injection routine with no apparent
adverse effects.
PROMOTING HOME AND
COMMUNITY-BASED CARE
Teaching
Patients Self-Care.
Adherence to the
therapeutic plan is the most important goal of self-care the patient must
master. Patients who are having difficulty adhering to the diabetes treatment
plan must be approached with care and understanding. Using scare tactics (such
as threats of blindness or amputation if the patient does not adhere to the
treatment plan) or making the patient feel guilty is not productive and may
interfere with establishing a trusting relationship with the patient.
Judgmental actions, such as asking the patient if he or she has “cheated” on
the diet, only promote feelings of guilt and low self-esteem. If problems exist
with glucose control or with the development of preventable complications, it
is important to distinguish among nonadherence, knowledge deficit, and
self-care deficit. It should not be assumed that problems with diabetes
management are related to nonadherence. The patient may simply have forgotten
or never learned certain information. The problem may be correctable simply through
providing complete information and ensuring that the patient comprehends the
information. Chart 41-8 details how to evaluate the effectiveness of
self-injection of insulin. If knowledge deficit is not the problem, certain
physical or emotional factors may be impairing the patient’s ability to perform
self-care skills. For example, decreased visual acuity may impair the patient’s
ability to administer insulin accurately, measure the blood glucose level, or
inspect the skin and feet. In addition, decreased joint mobility (especially in
the elderly) impairs the ability to inspect the bottom of the feet. Emotional
factors such as denial of the diagnosis or depression may impair the patient’s
ability to carry out multiple daily self-care measures. In other circumstances,
family, personal, or work problems may be of higher priority to the patient.
The patient facing competing demands for time and attention may benefit from
assistance in establishing priorities. It is also important to assess the
patient for infection or emotional stress that may lead to elevated blood
glucose levels despite adherence to the treatment regimen. The following
approaches by the nurse are helpful for promoting self-care management skills: • Address any
underlying factors (eg, knowledge deficit, selfcare deficit, illness) that may
affect diabetic control. • Simplify the treatment regimen if it is too difficult
for the patient to follow. • Adjust the treatment regimen to meet patient requests
(eg, adjust diet or insulin schedule to allow increased flexibility in meal
content or timing). • Establish a specific plan or contract with the patient
with simple, measurable goals. • Provide positive reinforcement of self-care behaviors
performed instead of focusing on behaviors that were neglected (eg, positively
reinforce blood glucose tests that were performed instead of focusing on the
number of missed tests). • Help the patient to identify personal motivating
factors rather than focusing on wanting to please the doctor or nurse. • Encourage the
patient to pursue life goals and interests; discourage an undue focus on
diabetes.
Continuing
Care.
As discussed,
continuing care of the patient with diabetes is critical in managing and
preventing complications. The degree to which the client interacts with health
care providers to obtain ongoing care depends on many factors. Age,
socioeconomic level, existing complications, type of diabetes, and comorbid
conditions all may dictate the frequency of follow-up visits. Many patients
with diabetes may be seen by home health nurses for diabetic education, wound
care, insulin preparation, or assistance with glucose monitoring. Even patients
who achieve excellent glucose control and have no complications can expect to
see their primary health care provider at least twice a year for ongoing
evaluation. In addition to follow-up care with health professionals,
participation in support groups is encouraged for those who have had diabetes
for many years as well as those who are newly diagnosed. Such participation may
assist the patient and family in coping with changes in lifestyle that occur
with the onset of diabetes and with its complications. Those who participate in
support groups often have an opportunity to share valuable information and
experiences and to learn from others. Support groups provide an opportunity for
discussion of strategies to deal with diabetes and its management and to
clarify and verify information with the nurse or other health care
professionals. Participation in support groups may help patients and their
families to become more knowledgeable about diabetes and its management and may
promote adherence to the management plan. Another very important role of the
nurse is to remind the patient about the importance of participating in other health
promotion activities and recommended health screening.
Acute Complications
of Diabetes
There are three
major acute complications of diabetes related to short-term imbalances in blood
glucose levels: hypoglycemia, DKA, and HHNS, which is also called hyperglycemic
hyperosmolar nonketotic coma or hyperglycemic hyperosmolar syndrome.
HYPOGLYCEMIA
(INSULIN REACTIONS)
Hypoglycemia
(abnormally low blood glucose level) occurs when the blood glucose falls to
less than 50 to 60 mg/dL (2.7 to 3.3 mmol/L). It can
be caused by too much insulin or oral hypoglycemic agents, too little food, or
excessive physical activity. Hypoglycemia may occur at any time of the day or
night. It often occurs before meals, especially if meals are delayed or snacks
are omitted. For example, midmorning hypoglycemia may occur when the morning
regular insulin is peaking, whereas hypoglycemia that occurs in the late
afternoon coincides with the peak of the morning NPH or Lente insulin.
Middle-of-the-night hypoglycemia may occur because of peaking evening or
predinner NPH or Lente insulins, especially in patients who have not eaten a
bedtime snack.
Clinical Manifestations
The clinical
manifestations of hypoglycemia may be grouped into two categories: adrenergic
symptoms and central nervous system (CNS) symptoms. In mild hypoglycemia, as
the blood glucose level falls, the sympathetic nervous system is stimulated,
resulting in a surge of epinephrine and norepinephrine. This causes symptoms
such as sweating, tremor, tachycardia, palpitation, nervousness, and hunger. In
moderate hypoglycemia, the fall in blood glucose level deprives the brain cells
of needed fuel for functioning. Signs of impaired function of the CNS may
include inability to concentrate, headache, lightheadedness, confusion, memory
lapses, numbness of the lips and tongue, slurred speech, impaired coordination,
emotional changes, irrational or combative behavior, double vision, and
drowsiness. Any combination of these symptoms (in addition to adrenergic
symptoms) may occur with moderate hypoglycemia. In severe hypoglycemia, CNS
function is so impaired that the patient needs the assistance of another person
for treatment of hypoglycemia. Symptoms may include disoriented behavior,
seizures, difficulty arousing from sleep, or loss of consciousness
Assessment and
Diagnostic Findings
Hypoglycemic
symptoms can occur suddenly and unexpectedly. The combination of symptoms
varies considerably from person to person. To some degree, this may be related
to the actual level to which the blood glucose drops or to the rate at which it
is dropping. For example, patients who usually have a blood glucose level in
the hyperglycemic range (eg, in the 200s or greater) may feel hypoglycemic
(adrenergic) symptoms when their blood glucose quickly drops to 120 mg/dL (6.6
mmol/L) or less. Conversely, patients who frequently have a glucose level in
the low range of normal may be asymptomatic when the blood glucose slowly falls
to less than 50 mg/dL (2.7 mmol/L). Another factor contributing to altered hypoglycemic
symptoms is a decreased hormonal (adrenergic) response to hypoglycemia. This
occurs in some patients who have had diabetes for many years. It may be related
to one of the chronic diabetic complications, autonomic neuropathy (see the
section in this chapter on hypoglycemic unawareness). As the blood glucose
level falls, the normal surge in adrenalin does not occur. The patient does not
feel the usual adrenergic symptoms, such as sweating and shakiness. The
hypoglycemia may not be detected until moderate or severe CNS impairment
occurs. These patients must perform SMBG on a frequent regular basis,
especially before driving or engaging in other potentially dangerous
activities.
Gerontologic
Considerations
In the elderly diabetic
patient, hypoglycemia is a particular concern for many reasons:
• Elderly people frequently live alone and may not
recognize the symptoms of hypoglycemia.
• With decreasing renal function, it takes longer for
oral hypoglycemic agents to be excreted by the kidneys.
• Skipping meals may occur because of decreased appetite
or financial limitations.
• Decreased visual acuity may lead to errors in insulin
administration.
Management
Immediate treatment must be given when hypoglycemia occurs. The usual
recommendation is for
• Three or four commercially prepared glucose tablets
• 4 to
• 6 to 10 Life Savers or other hard candies
• 2 to 3 teaspoons of sugar or honey
It is not necessary to add sugar to juice,
even if it is labeled as unsweetened juice: the fruit sugar in juice contains
enough carbohydrate to raise the blood glucose level. Adding table sugar to
juice may cause a sharp increase in the blood glucose level, and the patient
may experience hyperglycemia for hours after treatment. The blood glucose level
should be retested in 15 minutes and retreated if it is less than 70 to 75
mg/dL (3.8 to 4 mmol/L). If the symptoms persist more than 10 to 15 minutes
after initial treatment, the treatment is repeated even if blood glucose
testing is not possible. Once the symptoms resolve, a snack containing protein
and starch (eg, milk or cheese and crackers) is recommended unless the patient
plans to eat a regular meal or snack within 30 to 60 minutes.
TEACHING PATIENTS
It is important
for patients with diabetes, especially those receiving insulin, to learn that
they must carry some form of simple sugar with them at all times (
INITIATING
EMERGENCY MEASURES
For patients who
are unconscious and cannot swallow, an injection of glucagon 1 mg can be
administered either subcutaneously or intramuscularly. Glucagon is a hormone
produced by the alpha cells of the pancreas that stimulates the liver to
release glucose (through the breakdown of glycogen, the stored glucose).
Injectable glucagon is packaged as a powder in 1-mg vials and must be mixed
with a diluent before being injected. After injection of glucagon, it may take
up to 20 minutes for the patient to regain consciousness. A concentrated source
of carbohydrate followed by a snack should be given to the patient on awakening
to pre vent recurrence of hypoglycemia (because the duration of the action of 1
mg of glucagon is brief [its onset is 8 to 10 minutes and its action lasts 12
to 27 minutes]) and to replenish liver stores of glucose. Some patients
experience nausea after the administration of glucagon; if this occurs, the
patient should be turned to the side to prevent aspiration. The patient should
be instructed to notify the physician after severe hypoglycemia has occurred.
Glucagon is sold by prescription only and should be part of the emergency
supplies kept available by patients with diabetes who require insulin. Family
members, neighbors, or coworkers should be instructed in the use of glucagon.
This is especially true for patients who receive little or no warning of
hypoglycemic episodes. In the hospital or emergency department, patients who
are unconscious or cannot swallow may be treated with 25 to 50 mL 50% dextrose
in water (D50W) administered intravenously. The effect is usually seen within
minutes. Patients may complain of a headache and of pain at the injection site.
Assuring patency of the intravenous (IV) line used for injection of 50%
dextrose is essential because hypertonic solutions such as 50% dextrose are
very irritating to the vein.
PROMOTING HOME AND
COMMUNITY-BASED CARE
Teaching
Patients Self-Care.
Hypoglycemia is
prevented by a consistent pattern of eating, administering insulin, and
exercising. Between-meal and bedtime snacks may be needed to counteract the
maximum insulin effect. In general, the patient should cover the time of peak
activity of insulin by eating a snack and by taking additional food when physical
activity is increased. Routine blood glucose tests are performed so that
changing insulin requirements may be anticipated and the dosage adjusted.
Because unexpected hypoglycemia may occur, all patients treated with insulin
should wear an identification bracelet or tag stating that they have diabetes.
Patients and family members must be instructed about the symptoms of
hypoglycemia. Family members in particular must be made aware that any subtle
(but unusual) change in behavior may be an indication of hypoglycemia. They
should be taught to encourage and even insist that the person with diabetes
assess blood glucose levels if hypoglycemia is suspected. Some patients (when
hypoglycemic) become very resistant to testing or eating and become angry at family
members trying to treat the hypoglycemia. Family members must be taught to
persevere and to understand that the hypoglycemia can cause irrational
behavior. Some patients with autonomic neuropathy or those taking beta blockers
such as propranolol to treat hypertension or cardiac dysrhythmias may not
experience the typical symptoms of hypoglycemia. It is very important for these
patients to perform blood glucose tests on a frequent and regular basis.
Patients who have type 2 diabetes and who take oral sulfonylurea agents may
also develop hypoglycemia (especially those taking chlorpropamide, a
long-lasting oral hypoglycemic agent).
DIABETIC
KETOACIDOSIS
DKA is caused by
an absence or markedly inadequate amount of insulin. This deficit in available
insulin results in disorders in the metabolism of carbohydrate, protein, and
fat. The three main clinical features of DKA are: • Hyperglycemia • Dehydration and
electrolyte loss • Acidosis
Pathophysiology
Without insulin,
the amount of glucose entering the cells is reduced and the liver increases
glucose production. Both factors lead to hyperglycemia. In an attempt to rid
the body of the excess glucose, the kidneys excrete the glucose along with
water and electrolytes (eg, sodium and potassium). This osmotic diuresis, which
is characterized by excessive urination (polyuria), leads to dehydration and
marked electrolyte loss. Patients with severe DKA may lose up to
Clinical
Manifestations
The signs and
symptoms of DKA are listed in Figure 41-8. The hyperglycemia of DKA leads to
polyuria and polydipsia (increased thirst). In addition, patients may
experience blurred vision, weakness, and headache. Patients with marked intravascular
volume depletion may have orthostatic hypotension (drop in systolic blood
pressure of
Assessment and
Diagnostic Findings
Blood glucose
levels may vary from 300 to 800 mg/dL (16.6 to 44.4 mmol/L).
Some patients have lower glucose values, and others have values of 1,000 mg/dL
(55.5 mmol/L) or more (usually depending on the degree of dehydration). The
severity of DKA is not necessarily related to the blood glucose level. Some
patients may have severe acidosis with modestly elevated blood glucose levels,
whereas others may have no evidence of DKA despite blood glucose levels of 400
to 500 mg/dL (22.2 to 27.7 mmol/L) (Quinn, 2001c). Evidence of ketoacidosis is
reflected in low serum bicarbonate (0 to 15 mEq/L) and low pH (6.8 to 7.3)
values. A low PCO2 level (10 to
Prevention
For prevention of
DKA related to illness, patients must be taught “sick day” rules for managing
their diabetes when ill (Chart 41-9). The most important issue to teach
patients is not to eliminate insulin doses when nausea and vomiting occur.
Rather, they should take their usual insulin dose (or previously prescribed
special “sick day” doses) and then attempt to consume frequent small portions
of carbohydrates (including foods usually avoided, such as juices, regular
sodas, and gelatin). Drinking fluids every hour is important to prevent
dehydration. Blood glucose and urine ketones must be assessed every 3 to 4 hours.
If the patient cannot take fluids without vomiting, or if elevated glucose or
ketone levels persist, the physician must be contacted. Patients are taught to
have available foods for use on sick days. In addition, a supply of urine test
strips (for ketone testing) and blood glucose test strips should be available.
Patients must know how to contact their physician 24 hours a day. Diabetes
self-management skills (including insulin administration and blood glucose
testing) should be assessed to ensure that an error in insulin administration
or blood glucose testing did not occur. Psychological counseling is recommended
for patients and family members if an intentional alteration in insulin dosing
was the cause of the DKA.
Medical Management
In addition to treating
hyperglycemia, management of DKA is aimed at correcting dehydration,
electrolyte loss, and acidosis (Quinn, 2001c).
REHYDRATION
In dehydrated
patients, rehydration is important for maintaining tissue perfusion. In
addition, fluid replacement enhances the excretion of excessive glucose by the
kidneys. Patients may need up to 6 to
RESTORING ELECTROLYTES
The major
electrolyte of concern during treatment of DKA is potassium. Although the
initial plasma concentration of potassium may be low, normal, or even high,
there is a major loss of potassium from body stores and an intracellular to
extracellular shift of potassium. Further, the serum level of potassium drops
during the course of treatment of DKA as potassium re-enters the cells;
therefore, it must be monitored frequently. Some of the factors related to
treating DKA that reduce the serum potassium concentration include: • Rehydration, which
leads to increased plasma volume and subsequent decreases in the concentration
of serum potassium. Rehydration also leads to increased urinary excretion of
potassium. • Insulin administration, which enhances the movement of
potassium from the extracellular fluid into the cells. Cautious but timely
potassium replacement is vital to avoid dysrhythmias that may occur with
hypokalemia. Up to 40 mEq per hour may be needed for several hours. Because
extracellular potassium levels drop during DKA treatment, potassium must be
infused even if the plasma potassium level is normal.
Frequent (every 2
to 4 hours initially) electrocardiograms and laboratory measurements of
potassium are necessary during the first 8 hours of treatment. Potassium
replacement is withheld only if hyperkalemia is present or if the patient is
not urinating.