The working post of the secondary medical worker.

Organization of a nurse post functioning. Medical documentation and rules of ots fulfillment.  Thermometry, taking of blood pressure, examination of pulse, recording of obtained data into a temperature paper. Organization of a procedure room functioning.  Ordering, account and rules of stoage of drugs. The method and technique of taking blood for complete blood count, blood for determination of glucose content, for biochemical and bacteriological study.

The technique of subcutaneos, intramuscular and intavenous injections. Calculaion of a dosage of solble antibiotic.

The working post of the secondary medical worker.Nurse post is the basic place of the work of ward-nurse. The nurse post should be located not far from the wards under observation, or it may be inside the ward if the patient’s condition requires special  constant observation.The working post should be provided with a cabinet for medicines and instruments, a file cabinet for case histories, a telephone, and a table lamp. A signal  board  should he installed near the table of medical worker remains aware of the situation in the wards. A special table with a sterilizer and a locker for poisonous and strong medicines should also be provided. The working post should be maintained in strict compilable with hygiene requirements.

 

Nurse post.

Here there is a table with locked boxes for a storage of the medical documents, a case for storage of medicines, a refrigeration cabinet for the storage of perishable substances. The instruments, dressing material, inflammable substances (alcohol,  Ether), the instruments  for the patient’s care (thermometers, heaters, cupping-glass) are separately kept.

The nurse post should be provided with a telephone and a signal board. A signal board should be installed near the table so that the medical worker remains aware of the situation in the wards.

The  post nurses conduct the following documents: leafs of medical prescriptions, temperature  sheets, diet-sheets, register of transfer of shifts, register “movements of  the patients in the department”(entering to the hospital and discharge from the hospital), special records of the doctor’s prescriptions.

The case history should be kept under lock at the department  where the patient  is  treated. The main entries are made by  the  physician, while the muse  records information concerning procedures done to the patient and the results of  laboratory and instrumental examinations of the patient. Daily temperature of  the  patient,  his diuresis,’daily amounts of expectorated sputum, and all other  information as indicated by the physician are. also recorded by the nurse.

A senior nurse of each department keeps a book where she records all information about admitted patients:  his name, the preliminary diagnosis and the’ verified diagnosis upon the patient’s discharge from the hospital, the length of stay in the hospital, the patient’s sick leave, etc. The senior nurse keepsrecords  of  all strong-effective and poisonqus medicines  that are given to the patients.

Ward nurses and nurses on duty keep records of procedures done to the patients, of strong  and poisonous  medicines given to the patients during the day, compile charts for administration of medicines to the patients,etc; The nurse on duty registers the newly-admitted patients and those discharged from the ward during the day.

Daily duties are handed  ove  ‘from one nurse to another to ensure the necessary continuity. Doth nurses (the one going off duty and the one coming on) survey the wards, paying special attention to patients with severe diseases and newly-admitted patients. The nurse coming on  duty checks  the  sanitary condition of  the wards and other rooms. She obtains from  her  predecessor the list of doctor’s orders concerning preparing patients for x-ray examinations; collecting materials for  analyses, applying dry cups, mustard plasters, giving enemas, injections, etc. The individual charts, where the medication schedule is indicated for each particular patient. The thermometers, syringes, injectors, medicines, and other  important articles are handed over by one nurse to another. The keys from lockers where group A and B medicines are stored are also given to the new nurse on  duty,  Both  nurses put their signatures in the nurse coming on duty discovers any fault in the work of her predecessor, she must report to the senior  nurse or  the physician on duty. The senior nurse should supervise the formalities of changing shifts and report to the physician, in brief, the condition of the patients, fulfillment of  his orders, and the  sanitary condition of the department. The ward nurse may not leave her post until her successor takes over.

THERMOMETRY

Temperature refers to the hotness or coldness of a substance. Some living species are able to self-regulate the temperature of their body while others are warmed and cooled by conditions in the enviromment. Humans are homeo-thermic that is, they are warm-blooded and maintain body temperature independently of their environment.

It has been observed that environmental and physiological processes occur in repeated cycles of time. Some events in humans, appear to recur at 24-hour intervals. This cycling pattern is referred to as circadian (meaning nearly every 24 hours) rhythm. Predictable fluctuations in measurements of body temperature and blood pressure are examples of functions that exhibit a circadian rhythm.

The body temperature of a healthy person is maintained within a fairly constant range by the hypothalamus in the central nervous system. This structure is located at the base of the brain and plays an important role as the body’s thermostat. It normally allows the body temperature to vary only approximately 1 degree throughout the day. This constancy is referred to as the point. The set point can be altered by the body’s response to infectious agents, allergens, and inflamed tissue.

The hypothalamus has two parts: the anterior hypothalamus which controls heat dissipation, and the posterior hypothalamus that governs heat conservation. Thus, the set point is maintained by a balance of mechanisms involving heat production and heat loss. The following are examples of ways in which the body’s thermal balance is maintained:

•       Heat is produced through the metabolism of food. More heat is produced when the metabolism is increased, and less when the metabolism is decreased.

•       Heat production is increased by the body’s secretions of epinephrine, nonepinephrine, and thyroxin.

•    Exercise produces heat through muscle contraction.

•       The body’s surface, but not its internal structures, gains and loses heat physically from the sun, wind, and humidity in the environment.

•         Heat is transferred primarily through physical processes of

radiation, convection, evaporation, and conduction.

•         Heat is lost in small amounts through the urine, faeces,

and the process of warming and exhaling inspired air.

•      Changes in vascularity of the skin modify body temperature. When blood is directed to the skin through dilated vessels, heat loss is increased, when the skin vessels contract, heat is conserved.

•      The contraction of smooth muscles when gooseflesh occurs, and the involuntary movement of skeletal muscles when shivering is present, produce heat and promote the circulation of blood that has been wanned through this process.

In physiological conditions temperature of a body of healthy persons changes within the limits of 36,4 — 37,0° C. Variations normally occur in each person, and a range of 0,3 ° C to 0,6 ° C (0,5 ° F to 1,0 ° F) from the average normal temperature is considered to be within normal limit. For instance, body temperature is usually about 0,6 ° C lower in the early morning than in the late afternoon and early evening. This variation tends to be somewhat greater in infants and children. Current research indicates that the peak elevation of a person’s temperature will occur in late afternoon, between 4pm and 7 pm. However, wider variations from the average temperature have been found to be normal for certain persons. Newborns and young children normally have a higher body temperature than adults. The body’s internal organs require a fairly constant inner or core temperature for optimal functioning, whereas the surface and periphery of the body can fluctuate widely while gaining or losing heat.

Table  shows the average normal temperature standards for well adults at various bodv sites.

A patient’s temperature should be taken to reveal possible fever. It should be remembered, however, that an elevated temperature does not always correspond to the gravity of the patient’s condition]

Temperature can be measured by a several ways. Measuring body temperature in the hospital will be carried out in an axilla (armpit) by the Glass medical maximum thermometer. It gives as maximum because mercury column in a capillary of the thermometer in measuring body temperature, having reached a maximum level, does not fall to initial position independently. It is necessary to shake it until the mercury line reaches at least 36° C. This phenomenon is reached because the capillary of the thermometer has narrowing which reduces the back motion of the mercury in the tank after termination of thermal influence.

Glass thermometers are generally calibrated in either degrees Centigrade (Celsius) Fahrentheit, abbreviated C and F, respectively. The range is approximately 34 ° C (94 ° F) to approximately 42,2 ° C (108 ° F). The degrees on a thermometer using the Celsius scale are subdivided into gradients of 0,1; the subdivisions on a thermometer using the Fahrenheit scale are the equivalent to 0,2 degree.

Before giving the thermometer to the patient, it should be wiped dry, and the mercury column returned to the 34-35°C mark. The thermometer should be kept in the armpit so that the mercury bulb is in close contact with the skin on all its sides,

Axillary measurement of body temperature

The patient’s armpit should be dry because the wet thermometer reads a lower temperature. The thermometer should be kept in the armpit for about 10 minutes. If a patient is very weak and cannot hold the thermometer with the required force, he should be assisted.

In some cases the temperature can be measured by the oral or rectal methods. The thermometer should be held for about 5 minutes in the mouth (under the tongue) or inserting it in the rectum. In the latter case the thermometer should be coated with vaseline or another oil. The patient should He on his side, the thermometer being inserted into the rectum to half its length. The buttocks should be kept tight together. Rectal temperature (and temperature taken in the mouth) are 0.5-1 degree higher than that taken in the armpit.

Mercury types of thermometers

Oral measurement is contraindicated in patients who are unconscious, disoriented, or seizure-prone; in young children and infants; and in patients with oral or nasal impairment that necessitates mouth breathing.

Rectal measurement is contraindicated in patients with diarrhea, recent rectal or prostatic surgery or injury because it may injure inflamed tissue, in patients with a recent myocardial infarction because anal manipulation may stimulate the vagus nerve, causing bradycardia or another rhythm disturbance.

Temperature in infants should be measured in the groin. The thermometer is placed in the caudal genital fold, the infant’s thigh is flexed to the abdomen so that the thermometer bulb is hidden in the skin fold.

After taking the temperature, the thermometer should be washed thoroughly in warm water and then disinfected in 70% alcohol or some other disinfectant solution (2% solution of the chloraminum) not less than 10 minutes.

After disinfection the thermometer is rinsed with water, then is dried and returned to the storage receptacle. Thermometers should be kept in a glass containing cotton wool to prevent their breakage.

The temperature is usually taken two times a day at hospitals. The first measurement is done at 7.00-9.00 and the second at 17.00-19.00. If necessary, the temperature is taken at 3-hour intervals. The findings are recorded in a temperature chart, where the morning and evening temperatures are designated by dots which are then interconnected by a curve. Many diseases have their specific temperature curves. The temperature curve should be appended to the case history.

The elevation of body temperature over 37°C in adults is called fever (pyrexia, hyperthermia).

Pyrexia is a common symptom of illness, and there is sufficient to indicate that an elevation in temperature helps the body fight disease. In children, this response is often seen quickly. In the elderly person, pyrexia may be one of the later signs of illness, and the temperature may be elevated only 1 or 2 degrees above normal, even when pathologic processes are extensive.

Fever is usually caused by infection and products of tissue decomposition. Elevation of the temperature unconnected with infection is sometimes observed in malignant tumours or tissues necrosis (in myocardial infarction), tissue hemorrhages, rapid decomposition of red blood cells in the blood. Fever occurs less frequently in diseases of the central nervous system and also in  diseases of reflex etiology. Non-infectious  fever does not

strongly affect the patient’s condition and is usually transient. Temperature may elevates in physiological states.

Factors, that normally affect body temperature include:

–     Age: newborns and infants are subject to wide fluctuations; elderly persons experience deterioration in temperature regulation.

–  Exercise: muscle activity raises heat production.

–  Hormones: women have wider temperature fluctuations then man because of menstrual cycle hormonal changes.

–  Stress.

–  Environmental temperature.

–  Medications: some drugs impair sweating.

–  Daily fluctuations: body temperature is lowest during early morning; peaks in late afternoon; falls gradually during night.

Elevated temperature are characterized as follows: temperatures from 37° to 38°C are called subfebrile, from 38° to 39°C — moderately high, from 39° to 40°C — high, amd over 40°C — very high. Temperatures over 4I°C and 42°C are called hyperpyretic and are dangerous to the patient’s life. Death is probably due to the damaging effects to the respiratory center but may be due also to inactivation of body enzymes and destruction of tissue proteins.

The temperature may be only transient, and a for few hours (febris ephemeral). It occurs in mild infection, excess exposure to the sun, after blood transfusions, sometimes after intravenous injections of medical preparations. Fever lasting up to 15 days is called acute, from 15 about 45 days — subacute, more than 45 day — chronic.

Not only elevated temperature itself, but also its circadian variations are very importamt for diagnosing the diseases. Variations of temperature during the day determine the type of fever. The following main types of fever are differentiated.

 

The temperature list

1. Constant fever (febris continua) — within day the difference between morning and evening temperature does not exceed 1°C, morning temperature smaller than evening one. It is observed in patients with acute lobar pneumonia or II stage typhoid fever.

2. Remittent fever (febris remittems): the daily fluctuations of the temperature exceeds 1 C and the morning’s lowest temperature being over 37 °C, the morning temperature smaller than evening one. It often occurs in tuberculosis, purulent diseases, III stage typhoid fever and lobular pneumonia.

3. Intermittemt fever (febris intermittens), the daily fluctuations of the temperature exceed 1 °C, morning temperature smaller  than  evening  one.   The  body  temperature  alternates

regularly between a period of fever and a period of norma] temperature. It occurs in malaria.

4. Hectic fever (febris hectica): the temperature rises sharply (by 2 ° — 4 C) and drops to normal and subnormal level, that is often accompanied by excessive sweating, morning temperature smaller than evening one. It usually occurs in grave pulmonary tuberculosis, suppuration, sepsis and lymphogranulomatosis.

5. Inverse fever (febris inversus) is type of fever, when morning temperature is higher than evening. It sometimes occurs in sepsis, tuberculosis and brucellosis.

6. Irregular fever (febris irregularis) — the fever, when cicardian variations are varied and irregular. It often occurs in rheumatism, endocarditis, sepsis, tuberculosis.

According to the temperature curve recurrent (relapsing) and undulate (Malta) fever are distinguished.

7. Reccurent fever (febris reccurens) — is characterized by alternation of fever and afebrile periods. It occurs in relapsing fever.

8, Undulant fever (febris undulans) — is characterized by periodic elevation of the temperature followed by its drop. It often occurs in brucellosis and lymphogranulomatosis.

Temperature curves:

a—continuous fever; b—remittent fever; c—intermittent fever; d—hectic fever;e—irregular fever; f—inverted fever

The course of the fever is characterized by a period of elevation of the temperature (stadium increment!), which is followed by the period of high temperature (stadium fastigium) and ending with period of decreasing temperature (stadium decrement!).

In first period heat loss is decreased or heat production is increased. The degree of temperature rise is important for evaluating the patient’s condition. Fever is attended by accelerated heart and respiration rates and a fall in the arterial pressure. Patients complain of chill, headache, dry mouth, thirst, the absence of appetite and excess perspiration. Metabolism is intensified during the fever, while the amount of perspired liquid may be more than 8 liters a day. As a result of decreased appetite and liquid loss during a fever, the patient sometimes loses significant weight.

A quick and significant elevation of temperature is usually accompanied by a chill that continuing from a few minutes to an hour; in rare cases it may be continue longer. The blood vessels contract during chills, the skin turns pallid, and what is called gooseflesh develops. The patient feels cold, he shivers, his teeth chatter. If the temperature rises gradually, the patient may feel only a slight chill. Young children or persons with very high fevers may experience periods of delirium or seizures.

In the period of high temperature the skin reddens, becomes warm, the patient   feels hot. The respiration  and palpitation becomes frequent: in increasing the temperature on 1 C the pulse stroke  usually  becomes  frequent on 8-10 and respiration becomes frequent on 4 respiratory movements one minute. Very high temperature is accompanied by a delirium, sometimes by an  acute phenomena of exaltation. Constipations frequently occurs.

Decreasing temperature is characterized by decreasing of the heat production and increasing of heat loss. The temperature may decrease gradually, during several days. This termination of fever is called lysis. A sudden temperature drop to norm within 24 hours is called crisis.

A sudden drop in temperature is accompanied by heavy perspiration. The extremities become cold to the touch. Cyanosis of labiums occurs. The skin becomes covered by a cold clammy sweat, the pulse becomes steady. The gradual decreasing of the temperature is accompanied by an improvement of a condition.

Care for the patients with fever

During increasing of the temperature it is necessary to give the patient rest, to lay him in bed. and to apply a hot-water bottle to the legs, to avoid the draughts. Depending on the condition of the patient it is recommended at this time to give some tea or coffee to him. The nurse must keeps at the physiological excretions of the patient.

During a fever the toxic products are adsorbed in an organism. It is necessary to give the patient plenty of liquid such as fruit juices, mineral water without gases, for removing of the toxic products from organism. High-calory and easy assimilated food is given as a fluid or semifluid kind. The diet should include fruit and berry juices. In connection with the fall in appetite the patients is fed 6 times per day with small portions, limiting the salt. A bubble with ice, cold compress from a gauze napkin combined four times and moistened in a solution of Acetum (50 ml on 0,5 1 of the water) is put on forehead for a sharp headache. The wiping and irrigation of an oral cavity with 2% sol. of a hydrocarbonate, and also moistening of labium cracks with a liquid sol. of Glycerinum or children’s cream is necessary in the dryness of the oral cavity and fracturing on the lips.

If the patient develops delirium or hallucinations his bed should be provided with a protective structures to prevent him from falling out of bed. A special post for the nurse should be arranged at his bedside.

In loss of consciousness, the constant control of the pulse and respiration rates would be necessary. In a long term bed patients it is necessary to carry out prophylaxis for skin ulcers. The cleansing enemas are used for constipation. The patient is on a strict bed regimen.

In resolution of the pyrexia as crisis, the patient puts hot water bottles all round himself. If the patient perspires excessively, his bedclothes and underwear should be changed several times a day. Since sweat evaporates from the skin and leaves metabolites on its surface (salts, urea), the skin should be cleansed with water mixed with alcohol or vinegar, or toilet water (1:1).

Special attention should be given to the patient during a critical fall of temperature which is often attended by a fall in arterial pressure (collapse).

Vascular and respiratory analeptics — Cordiaminum, Sulfocamphocainum, Camphora, coffeine, phenylephine hydrochloride are given to the patient, if the arterial pressure drops.

Subnormal body temperature

A body temperature below the lower limit of normal is called hypothermia. Death may occur when the temperature falls below approximately 34 °C (93,2 F), but survival has been reported in isolated cases when body temperatures have fallen in the range of severe hypothermia (28  C or 82,4 °F).

Subnormal temperatures may be caused by:

1) excessive heat elimination from profuse sweating, severe hemorrhage, or loss of other body fluids;

2)    lessened heat production, as in shock or collapse; and

3)    long exposure to cold environments (this may happen to a person drowning in cold water or buried by snow).

Because body functions are almost imperceptible at this range, health-care personnel should attempt to warm hypothermic patients and continue resuscitation efforts.

Just as elevated body temperature is a protective device for the body, a lowered body temperature may be beneficial also. Rates of chemical reactions in the body are slowed, thereby decreasing the metabolic demands for oxygen.

Patients hopelessly ill with cancer have been treated in recent years with generalized applications of cold or exposure to cold rooms for days at a time. It was thought at first that the maintenance of body temperatures from 24° C (75,2° F) to 32° C (89,6° F) brought relief and arrest of that disease, but although the patients survived these temperatures, the value of the therapy is now questioned.

Thermovision

This method is based on detection of zones with increased infra-red radiation emanating from the organs affected by acute inflammatory, cancerous and other diseases by using a special apparatus – the thermovision system. Measuring temperature inside some hollow organs (stomach, large intestine) by special radio devices is of great diagnostic significance.

Taking blood pressure. Normal indexes.

Blood pressure (BP), sometimes referred to as arterial blood pressure, is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, “blood pressure” usually refers to the arterial pressure of the systemic circulation. During each heartbeat, blood pressure varies between a maximum (systolic) and a minimum (diastolic) pressure. The blood pressure in the circulation is principally due to the pumping action of the heart. Differences in mean blood pressure are responsible for blood flow from one location to another in the circulation. The rate of mean blood flow depends on the resistance to flow presented by the blood vessels. Mean blood pressure decreases as the circulating blood moves away from the heart through arteries and capillaries due to viscous losses of energy. Mean blood pressure drops over the whole circulation, although most of the fall occurs along the small arteries and arterioles. Gravity affects blood pressure via hydrostatic forces (e.g., during standing) and valves in veins, breathing, and pumping from contraction of skeletal muscles also influence blood pressure in veins.

The measurement blood pressure without further specification usually refers to the systemic arterial pressure measured at a person’s upper arm and is a measure of the pressure in the brachial artery, major artery in the upper arm. A person’s blood pressure is usually expressed in terms of the systolic pressure over diastolic pressure and is measured in millimetres of mercury (mmHg), for example 120/80.

 

 

Classification of blood pressure for adults

 

Classification

The table on the right shows the classification of blood pressure adopted by the American Heart Association for adults who are 18 years and older. It assumes the values are a result of averaging blood pressure readings measured at two or more visits to the doctor.

In the UK, blood pressures are usually categorised into three groups: low (90/60 or lower), high (140/90 or higher), and normal (values above 90/60 and below 130/80).

While average values for arterial pressure could be computed for any given population, there is often a large variation from person to person; arterial pressure also varies in individuals from moment to moment. Additionally, the average of any given population may have a questionable correlation with its general health; thus the relevance of such average values is equally questionable. However, in a study of 100 human subjects with no known history of hypertension, an average blood pressure of 112/64 mmHg was found, which are currently classified as desirable or “normal” values. Normal values fluctuate through the 24-hour cycle, with highest readings in the afternoons and lowest readings at night.

Various factors, such as age and sex influence average values, influence a person’s average blood pressure and variations. In children, the normal ranges are lower than for adults and depend on height. As adults age, systolic pressure tends to rise and diastolic tends to fall. In the elderly, blood pressure tends to be above the normal adult range, largely because of reduced flexibility of the arteries. Also, an individual’s blood pressure varies with exercise, emotional reactions, sleep, digestion and time of day.

Differences between left and right arm blood pressure measurements tend to be random and average to nearly zero if enough measurements are taken. However, in a small percentage of cases there is a consistent difference greater than 10 mmHg which may need further investigation, e.g. for obstructive arterial disease.

The risk of cardiovascular disease increases progressively above 115/75 mmHg. In the past, hypertension was only diagnosed if secondary signs of high arterial pressure were present, along with a prolonged high systolic pressure reading over several visits. Regarding hypotension, in practice blood pressure is considered too low only if noticeable symptoms are present.

Clinical trials demonstrate that people who maintain arterial pressures at the low end of these pressure ranges have much better long term cardiovascular health. The principal medical debate concerns the aggressiveness and relative value of methods used to lower pressures into this range for those who do not maintain such pressure on their own. Elevations, more commonly seen in older people, though often considered normal, are associated with increased morbidity and mortality.

Some physical factors are:

Volume of fluid or blood volume, the amount of blood that is present in the body. The more blood present in the body, the higher the rate of blood return to the heart and the resulting cardiac output. There is some relationship between dietary salt intake and increased blood volume, potentially resulting in higher arterial pressure, though this varies with the individual and is highly dependent on autonomic nervous system response and the renin-angiotensin system.

Resistance. In the circulatory system, this is the resistance of the blood vessels. The higher the resistance, the higher the arterial pressure upstream from the resistance to blood flow. Resistance is related to vessel radius (the larger the radius, the lower the resistance), vessel length (the longer the vessel, the higher the resistance), blood viscosity, as well as the smoothness of the blood vessel walls. Smoothness is reduced by the build up of fatty deposits on the arterial walls. Substances called vasoconstrictors can reduce the size of blood vessels, thereby increasing blood pressure. Vasodilators (such as nitroglycerin) increase the size of blood vessels, thereby decreasing arterial pressure. Resistance, and its relation to volumetric flow rate (Q) and pressure difference between the two ends of a vessel are described by Poiseuille’s Law.

Viscosity, or thickness of the fluid. If the blood gets thicker, the result is an increase in arterial pressure. Certain medical conditions can change the viscosity of the blood. For instance, anemia (low red blood cell concentration), reduces viscosity, whereas increased red blood cell concentration increases viscosity. It had been thought that aspirin and related “blood thinner” drugs decreased the viscosity of blood, but instead studies found that they act by reducing the tendency of the blood to clot.

In practice, each individual’s autonomic nervous system responds to and regulates all these interacting factors so that, although the above issues are important, the actual arterial pressure response of a given individual varies widely because of both split-second and slow-moving responses of the nervous system and end organs. These responses are very effective in changing the variables and resulting blood pressure from moment to moment.

Moreover, blood pressure is the result of cardiac output increased by peripheral resistance: blood pressure = cardiac output X peripheral resistance. As a result, an abnormal change in blood pressure is often an indication of a problem affecting the heart’s output, the blood vessels’ resistance, or both. Thus, knowing the patient’s blood pressure is critical to assess any pathology related to output and resistance.

Mean arterial pressure

The mean arterial pressure (MAP) is the average over a cardiac cycle and is determined by the cardiac output (CO), systemic vascular resistance (SVR), and central venous pressure (CVP), 

MAP can be approximately determined from measurements of the systolic pressure   and the diastolic pressure  

Pulse pressure

The up and down fluctuation of the arterial pressure results from the pulsatile nature of the cardiac output, i.e. the heartbeat. The pulse pressure is determined by the interaction of the stroke volume of the heart, compliance (ability to expand) of the aorta, and the resistance to flow in the arterial tree. By expanding under pressure, the aorta absorbs some of the force of the blood surge from the heart during a heartbeat. In this way, the pulse pressure is reduced from what it would be if the aorta wasn’t compliant. The loss of arterial compliance that occurs with aging explains the elevated pulse pressures found in elderly patients.

Curve of the arterial pressure during one cardiac cycle

The pulse pressure can be simply calculated from the difference of the measured systolic and diastolic pressures,

 

 

Arm–leg gradient

 

The arm–leg (blood pressure) gradient is the difference between the blood pressure measured in the arms and that measured in the legs. It is normally less than 10 mmHg, but may be increased in e.g. coarctation of the aorta.

Vascular resistance

The larger arteries, including all large enough to see without magnification, are conduits with low vascular resistance (assuming no advanced atherosclerotic changes) with high flow rates that generate only small drops in pressure. The smaller arteries and arterioles have higher resistance, and confer the main drop in blood pressure along the circulatory system.

 

Vascular pressure wave

Modern physiology developed the concept of the vascular pressure wave (VPW). This wave is created by the heart during the systole and originates in the ascending aorta. Much faster than the stream of blood itself, it is then transported through the vessel walls to the peripheral arteries. There the pressure wave can be palpated as the peripheral pulse. As the wave is reflected at the peripheral veins, it runs back in a centripetal fashion. When the reflected wave meets the next outbound pressure wave, the pressure inside the vessel rises higher than the pressure in the aorta. This concept explains why the arterial pressure inside the peripheral arteries of the legs and arms is higher than the arterial pressure in the aorta, and in turn for the higher pressures seen at the ankle compared to the arm with normal ankle brachial pressure index values.

Regulation

The endogenous regulation of arterial pressure is not completely understood, but the following mechanisms of regulating arterial pressure have been well-characterized:

Baroreceptor reflex: Baroreceptors in the high pressure receptor zones detect changes in arterial pressure. These baroreceptors send signals ultimately to the medulla of the brain stem, specifically to the Rostral ventrolateral medulla (RVLM). The medulla, by way of the autonomic nervous system, adjusts the mean arterial pressure by altering both the force and speed of the heart’s contractions, as well as the total peripheral resistance. The most important arterial baroreceptors are located in the left and right carotid sinuses and in the aortic arch.

Renin-angiotensin system (RAS): This system is generally known for its long-term adjustment of arterial pressure. This system allows the kidney to compensate for loss in blood volume or drops in arterial pressure by activating an endogenous vasoconstrictor known as angiotensin II.

Aldosterone release: This steroid hormone is released from the adrenal cortex in response to angiotensin II or high serum potassium levels. Aldosterone stimulates sodium retention and potassium excretion by the kidneys. Since sodium is the main ion that determines the amount of fluid in the blood vessels by osmosis, aldosterone will increase fluid retention, and indirectly, arterial pressure.

Baroreceptors in low pressure receptor zones (mainly in the venae cavae and the pulmonary veins, and in the atria) result in feedback by regulating the secretion of antidiuretic hormone (ADH/Vasopressin), renin and aldosterone. The resultant increase in blood volume results an increased cardiac output by the Frank–Starling law of the heart, in turn increasing arterial blood pressure.

These different mechanisms are not necessarily independent of each other, as indicated by the link between the RAS and aldosterone release. Currently, the RAS is targeted pharmacologically by ACE inhibitors and angiotensin II receptor antagonists. The aldosterone system is directly targeted by spironolactone, an aldosterone antagonist. The fluid retention may be targeted by diuretics; the antihypertensive effect of diuretics is due to its effect on blood volume. Generally, the baroreceptor reflex is not targeted in hypertension because if blocked, individuals may suffer from orthostatic hypotension and fainting.

Measurement

Arterial pressure is most commonly measured via a sphygmomanometer, which historically used the height of a column of mercury to reflect the circulating pressure. Blood pressure values are generally reported in millimetres of mercury (mmHg), though aneroid and electronic devices do not use mercury.

For each heartbeat, blood pressure varies between systolic and diastolic pressures. Systolic pressure is peak pressure in the arteries, which occurs near the end of the cardiac cycle when the ventricles are contracting. Diastolic pressure is minimum pressure in the arteries, which occurs near the beginning of the cardiac cycle when the ventricles are filled with blood. An example of normal measured values for a resting, healthy adult human is 120 mmHg systolic and 80 mmHg diastolic (written as 120/80 mmHg, and spoken [in the US and UK] as “one-twenty over eighty”).

Systolic and diastolic arterial blood pressures are not static but undergo natural variations from one heartbeat to another and throughout the day (in a circadian rhythm). They also change in response to stress, nutritional factors, drugs, disease, exercise, and momentarily from standing up. Sometimes the variations are large. Hypertension refers to arterial pressure being abnormally high, as opposed to hypotension, when it is abnormally low. Along with body temperature, respiratory rate, and pulse rate, blood pressure is one of the four main vital signs routinely monitored by medical professionals and healthcare providers.

Measuring pressure invasively, by penetrating the arterial wall to take the measurement, is much less common and usually restricted to a hospital setting.

Noninvasive

The noninvasive auscultatory and oscillometric measurements are simpler and quicker than invasive measurements, require less expertise, have virtually no complications, are less unpleasant and less painful for the patient.

However, noninvasive methods may yield somewhat lower accuracy and small systematic differences iumerical results. Noninvasive measurement methods are more commonly used for routine examinations and monitoring.

Palpation

A minimum systolic value can be roughly estimated by palpation, most often used in emergency situations, but should be used with caution. It has been estimated that, using 50% percentiles, carotid, femoral and radial pulses are present in patients with a systolic blood pressure > 70 mmHg, carotid and femoral pulses alone in patients with systolic blood pressure of > 50 mmHg, and only a carotid pulse in patients with a systolic blood pressure of > 40 mmHg.

A more accurate value of systolic blood pressure can be obtained with a sphygmomanometer and palpating the radial pulse. The diastolic blood pressure cannot be estimated by this method. The American Heart Association recommends that palpation be used to get an estimate before using the auscultatory method.

Auscultatory

The auscultatory method (from the Latin word for “listening”) uses a stethoscope and a sphygmomanometer. This comprises an inflatable (Riva-Rocci) cuff placed around the upper arm at roughly the same vertical height as the heart, attached to a mercury or aneroid manometer. The mercury manometer, considered the gold standard, measures the height of a column of mercury, giving an absolute result without need for calibration and, consequently, not subject to the errors and drift of calibration which affect other methods. The use of mercury manometers is often required in clinical trials and for the clinical measurement of hypertension in high-risk patients, such as pregnant women.

Auscultatory method aneroid sphygmomanometer with stethoscope

A cuff of appropriate size is fitted smoothly and snugly, then inflated manually by repeatedly squeezing a rubber bulb until the artery is completely occluded. Listening with the stethoscope to the brachial artery at the elbow, the examiner slowly releases the pressure in the cuff. When blood just starts to flow in the artery, the turbulent flow creates a “whooshing” or pounding (first Korotkoff sound). The pressure at which this sound is first heard is the systolic blood pressure. The cuff pressure is further released until no sound can be heard (fifth Korotkoff sound), at the diastolic arterial pressure.

The auscultatory method is the predominant method of clinical measurement.

Mercury manometer

The auscultatory method (from the Latin word for “listening”) uses a stethoscope and a sphygmomanometer. This comprises an inflatable (Riva-Rocci) cuff placed around the upper arm at roughly the same vertical height as the heart, attached to a mercury or aneroid manometer. The mercury manometer, considered the gold standard, measures the height of a column of mercury, giving an absolute result without need for calibration and, consequently, not subject to the errors and drift of calibration which affect other methods.

Mercury manometer

 

The use of mercury manometers is often required in clinical trials and for the clinical measurement of hypertension in high-risk patients, such as pregnant women.

A cuff of appropriate size is fitted smoothly and snugly, then inflated manually by repeatedly squeezing a rubber bulb until the artery is completely occluded. Listening with the stethoscope to the brachial artery at the elbow, the examiner slowly releases the pressure in the cuff. When blood just starts to flow in the artery, the turbulent flow creates a “whooshing” or pounding (first Korotkoff sound). The pressure at which this sound is first heard is the systolic blood pressure. The cuff pressure is further released until no sound can be heard (fifth Korotkoff sound), at the diastolic arterial pressure.

The auscultatory method is the predominant method of clinical measurement.

Oscillometric

The oscillometric method was first demonstrated in 1876 and involves the observation of oscillations in the sphygmomanometer cuff pressure which are caused by the oscillations of blood flow, i.e., the pulse. The electronic version of this method is sometimes used in long-term measurements and general practice. It uses a sphygmomanometer cuff, like the auscultatory method, but with an electronic pressure sensor (transducer) to observe cuff pressure oscillations, electronics to automatically interpret them, and automatic inflation and deflation of the cuff. The pressure sensor should be calibrated periodically to maintain accuracy.

Oscillometric measurement requires less skill than the auscultatory technique and may be suitable for use by untrained staff and for automated patient home monitoring.

The cuff is inflated to a pressure initially in excess of the systolic arterial pressure and then reduced to below diastolic pressure over a period of about 30 seconds. When blood flow is nil (cuff pressure exceeding systolic pressure) or unimpeded (cuff pressure below diastolic pressure), cuff pressure will be essentially constant. It is essential that the cuff size is correct: undersized cuffs may yield too high a pressure; oversized cuffs yield too low a pressure. When blood flow is present, but restricted, the cuff pressure, which is monitored by the pressure sensor, will vary periodically in synchrony with the cyclic expansion and contraction of the brachial artery, i.e., it will oscillate. The values of systolic and diastolic pressure are computed, not actually measured from the raw data, using an algorithm; the computed results are displayed.

Oscillometric monitors may produce inaccurate readings in patients with heart and circulation problems, which include arterial sclerosis, arrhythmia, preeclampsia, pulsus alternans, and pulsus paradoxus.

In practice the different methods do not give identical results; an algorithm and experimentally obtained coefficients are used to adjust the oscillometric results to give readings which match the auscultatory results as well as possible. Some equipment uses computer-aided analysis of the instantaneous arterial pressure waveform to determine the systolic, mean, and diastolic points. Since many oscillometric devices have not been validated, caution must be given as most are not suitable in clinical and acute care settings.

The term NIBP, for non-invasive blood pressure, is often used to describe oscillometric monitoring equipment.

Continuous noninvasive techniques (CNAP)

Continuous Noninvasive Arterial Pressure (CNAP) is the method of measuring arterial blood pressure in real-time without any interruptions and without cannulating the human body. CNAP combines the advantages of the following two clinical “gold standards”: it measures blood pressure continuously in real-time like the invasive arterial catheter system and it is noninvasive like the standard upper arm sphygmomanometer. Latest developments in this field show promising results in terms of accuracy, ease of use and clinical acceptance.

Non-occlusive techniques: the Pulse Wave Velocity (PWV) principle

Since the 90s a novel family of techniques based on the so-called Pulse wave velocity (PWV) principle have been developed. These techniques rely on the fact that the velocity at which an arterial pressure pulse travels along the arterial tree depends, among others, on the underlying blood pressure. Accordingly, after a calibration maneuver, these techniques provide indirect estimates of blood pressure by translating PWV values into blood pressure values.

The main advantage of these techniques is that it is possible to measure PWV values of a subject continuously (beat-by-beat), without medical supervision, and without the need of inflating brachial cuffs. PWV-based techniques are still in the research domain and are not adapted to clinical settings.

White-coat hypertension

For some patients, blood pressure measurements taken in a doctor’s office may not correctly characterize their typical blood pressure. In up to 25% of patients, the office measurement is higher than their typical blood pressure. This type of error is called white-coat hypertension (WCH) and can result from anxiety related to an examination by a health care professional. The misdiagnosis of hypertension for these patients can result ieedless and possibly harmful medication. WCH can be reduced (but not eliminated) with automated blood pressure measurements over 15 to 20 minutes in a quiet part of the office or clinic.

Debate continues regarding the significance of this effect.[citatioeeded] Some reactive patients will react to many other stimuli throughout their daily lives and require treatment. In some cases a lower blood pressure reading occurs at the doctor’s office.

Home monitoring

Ambulatory blood pressure devices that take readings every half hour throughout the day and night have been used for identifying and mitigating measurement problems like white-coat hypertension. Except for sleep, home monitoring could be used for these purposes instead of ambulatory blood pressure monitoring. Home monitoring may be used to improve hypertension management and to monitor the effects of lifestyle changes and medication related to blood pressure. Compared to ambulatory blood pressure measurements, home monitoring has been found to be an effective and lower cost alternative, but ambulatory monitoring is more accurate than both clinic and home monitoring in diagnosing hypertension. Ambulatory monitoring is recommended for most patients before the start of antihypertensive drugs.

Aside from the white-coat effect, blood pressure readings outside of a clinical setting are usually slightly lower in the majority of people. The studies that looked into the risks from hypertension and the benefits of lowering blood pressure in affected patients were based on readings in a clinical environment.

When measuring blood pressure, an accurate reading requires that one not drink coffee, smoke cigarettes, or engage in strenuous exercise for 30 minutes before taking the reading. A full bladder may have a small effect on blood pressure readings; if the urge to urinate arises, one should do so before the reading. For 5 minutes before the reading, one should sit upright in a chair with one’s feet flat on the floor and with limbs uncrossed. The blood pressure cuff should always be against bare skin, as readings taken over a shirt sleeve are less accurate. During the reading, the arm that is used should be relaxed and kept at heart level, for example by resting it on a table.

Since blood pressure varies throughout the day, measurements intended to monitor changes over longer time frames should be taken at the same time of day to ensure that the readings are comparable. Suitable times are:

immediately after awakening (before washing/dressing and taking breakfast/drink), while the body is still resting, immediately after finishing work.

Automatic self-contained blood pressure monitors are available at reasonable prices, some of which are capable of Korotkoff’s measurement in addition to oscillometric methods, enabling irregular heartbeat patients to accurately measure their blood pressure at home.

Invasive

Arterial blood pressure (BP) is most accurately measured invasively through an arterial line. Invasive arterial pressure measurement with intravascular cannulae involves direct measurement of arterial pressure by placing a cannula needle in an artery (usually radial, femoral, dorsalis pedis or brachial).

The cannula must be connected to a sterile, fluid-filled system, which is connected to an electronic pressure transducer. The advantage of this system is that pressure is constantly monitored beat-by-beat, and a waveform (a graph of pressure against time) can be displayed. This invasive technique is regularly employed in human and veterinary intensive care medicine, anesthesiology, and for research purposes.

Cannulation for invasive vascular pressure monitoring is infrequently associated with complications such as thrombosis, infection, and bleeding. Patients with invasive arterial monitoring require very close supervision, as there is a danger of severe bleeding if the line becomes disconnected. It is generally reserved for patients where rapid variations in arterial pressure are anticipated.

Invasive vascular pressure monitors are pressure monitoring systems designed to acquire pressure information for display and processing. There are a variety of invasive vascular pressure monitors for trauma, critical care, and operating room applications. These include single pressure, dual pressure, and multi-parameter (i.e. pressure / temperature). The monitors can be used for measurement and follow-up of arterial, central venous, pulmonary arterial, left atrial, right atrial, femoral arterial, umbilical venous, umbilical arterial, and intracranial pressures.

High

Arterial hypertension can be an indicator of other problems and may have long-term adverse effects. Sometimes it can be an acute problem, for example hypertensive emergency.

All levels of arterial pressure put mechanical stress on the arterial walls. Higher pressures increase heart workload and progression of unhealthy tissue growth (atheroma) that develops within the walls of arteries. The higher the pressure, the more stress that is present and the more atheroma tend to progress and the heart muscle tends to thicken, enlarge and become weaker over time.

Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysms, and is the leading cause of chronic renal failure. Even moderate elevation of arterial pressure leads to shortened life expectancy. At severely high pressures, mean arterial pressures 50% or more above average, a person can expect to live no more than a few years unless appropriately treated.

In the past, most attention was paid to diastolic pressure; but nowadays it is recognised that both high systolic pressure and high pulse pressure (the numerical difference between systolic and diastolic pressures) are also risk factors. In some cases, it appears that a decrease in excessive diastolic pressure can actually increase risk, due probably to the increased difference between systolic and diastolic pressures (see the article on pulse pressure). If systolic blood pressure is elevated (>140) with a normal diastolic blood pressure (<90), it is called “isolated systolic hypertension” and may present a health concern.

Overview of main complications of persistent high blood pressure.

For those with heart valve regurgitation, a change in its severity may be associated with a change in diastolic pressure. In a study of people with heart valve regurgitation that compared measurements 2 weeks apart for each person, there was an increased severity of aortic and mitral regurgitation when diastolic blood pressure increased, whereas when diastolic blood pressure decreased, there was a decreased severity.

Low

Blood pressure that is too low is known as hypotension. The similarity in pronunciation with hypertension can cause confusion. Hypotension is a medical concern if it causes signs or symptoms, such as dizziness, fainting, or in extreme cases, shock.

When arterial pressure and blood flow decrease beyond a certain point, the perfusion of the brain becomes critically decreased (i.e., the blood supply is not sufficient), causing lightheadedness, dizziness, weakness or fainting.

Sometimes the arterial pressure drops significantly when a patient stands up from sitting. This is known as orthostatic hypotension (postural hypotension); gravity reduces the rate of blood return from the body veins below the heart back to the heart, thus reducing stroke volume and cardiac output.

When people are healthy, the veins below their heart quickly constrict and the heart rate increases to minimize and compensate for the gravity effect. This is carried out involuntarily by the autonomic nervous system. The system usually requires a few seconds to fully adjust and if the compensations are too slow or inadequate, the individual will suffer reduced blood flow to the brain, dizziness and potential blackout. Increases in G-loading, such as routinely experienced by aerobatic or combat pilots ‘pulling Gs’, greatly increases this effect. Repositioning the body perpendicular to gravity largely eliminates the problem.

Other causes of low arterial pressure include:

·                    Sepsis

·                    Hemorrhage – blood loss

·                    Toxins including toxic doses of blood pressure medicine

·                    Hormonal abnormalities, such as Addison’s disease

·                    Eating disorders, particularly anorexia nervosa and bulimia

 

Shock is a complex condition which leads to critically decreased perfusion. The usual mechanisms are loss of blood volume, pooling of blood within the veins reducing adequate return to the heart and/or low effective heart pumping. Low arterial pressure, especially low pulse pressure, is a sign of shock and contributes to and reflects decreased perfusion.

If there is a significant difference in the pressure from one arm to the other, that may indicate a narrowing (for example, due to aortic coarctation, aortic dissection, thrombosis or embolism) of an artery .

Fluctuating blood pressure

Normal fluctuation in blood pressure is adaptive and necessary. Fluctuations in pressure that are significantly greater than the norm are associated with greater white matter hyperintensity, a finding consistent with reduced local cerebral blood flow and a heightened risk of cerebrovascular disease. Within both high- and low-blood pressure groups, a greater degree of fluctuation was found to correlate with an increase in cerebrovascular disease compared to those with less variability, suggesting the consideration of the clinical management of blood pressure fluctuations, even among normotensive older adults. Older individuals and those who had received blood pressure medications were more likely to exhibit larger fluctuations in pressure.

Step 1

First the patient must be made to lie down. Measuring blood pressure while standing is not advisable, as the correct blood pressure is only recorded when a patient is in a supine position. This is the position in which the person’s heart is not under any kind of stress and the heartbeat is normal.

Step 2

The brachial artery is palpable on the medial side of the brachialis tendon which can be found on the inside of the arm. In simple words, flex your arm slightly and you will be able to palpate a tendon and on the inner side of this tendon (towards the body) you will find the brachial artery. So, once the brachial artery is identified, wrap the cuff tightly, around the area, just above the brachial artery. Take care of placing the diaphragm part of the chest-piece of the stethoscope on the brachial artery.

Step 3

 

After the cuff is secured into place, close the valve and slowly start pumping the air bulb, which will make the mercury column rise. Be sure to do this slowly, so that the person does not feel sudden pain due to ischemia. Also, do not raise the pressure to more than 150mm of Hg to be on the safe side, unless it is known that the person is suffering from high blood pressure. Ideally, raise the pressure till the heart sounds are not heard anymore through the stethoscope.

Step 4

Now, slowly release the pressure and wait till you hear heart sounds. These sounds are known as Korotkoff sounds. They are heard, because the normal streamline flow of blood is suddenly hindered and again, when the pressure is released, the blood flows turbulently and gushes through, causing these sounds. Thus, the level of pressure at which the first sound is heard marks the systolic blood pressure. Then, when the sound slowly starts to fade away and just before, it completely disappears, that reading will mark the diastolic blood pressure.

Step 5

If you perform the procedure but are not sure of the readings you got while measuring blood pressure, you can repeat the procedure immediately, provided the person is not complaining of pain in the arm. During the procedure, if the persons arm suddenly turns white and spasmodic and the person complains of pain, then it is best to immediately release the pressure by opening the valve completely.

The normal blood pressure range is around 120/80 mm of Hg, with 120 signifying the systolic pressure and 80 the diastolic pressure; anything above 140/90 mm of Hg, is normally considered to be a high blood pressure.

In people who are either very obese or people who suffer from arteriosclerosis, identifying and auscultating the brachial artery becomes difficult. In such cases, using a finger blood pressure monitor is a good option. All said and done, taking blood pressure isn’t so hard after all – with just a little bit of patience and practice, you can master it io time!

Each time your heart beats it forces a surge of blood through your arteries. The alternate expansion and recoil of elastic arteries after each systole of the left ventricle cleating a traveling pressure wave that is called the Pulse.  The pulse is the same as the heart rate. The speed at which your heart beats changes many times every day. You can measure the speed by taking your pulse. Pulse – the number of beats your heart performs per minute.

n    Represents the expansile impulse produced by ventricular ejection & transmitted along the arteries.

n    Reflects the performance of Lt.Ventricle & response of arterial system to Lt.Ventricular ejection.

n    Pulse wave is transmitted along aorta to periphery at a speed of 5m/sec but intraluminal blood travels much slower (40-50cm/sec)

                        

The pulse can be measured at any place where there is a large artery (e.g. carotid, femoral, or simply by listening over the heart), though for the sake of convenience it is generally done by palpating the radial artery’s impulse.

 

You may find it helpful to feel both radial arteries simultaneously, doubling the sensory input and helping to insure the accuracy of your measurements. Place the tips of your index and middle fingers just proximal to the patients wrist on the thumb side, orienting them so that they are both over the length of the vessel.

 Brachial Pulse : In antecubital fossa medial to biceps tendon. Use your thumb with your fingers cupped round the back of elbow.

 

In human anatomy, the radial artery is the main artery of the lateral aspect of the forearm. Radial Pulse : At wrist, lateral to flexor carpi radialis tendon , place your three middle fingers over the radial pulse. The normal adult pulse is 60 to 90 beats a minute. Arteries are the vessels that carry blood from the heart to different parts of your body. It is easier to feel the pulse in arteries that come close to the skin.

 

CAROTID ARTERY (side of neck)
Carotid Pulse : Palpate carotid pulse with the pt lying on a bed / couch

Find your Adam’s apple and place your fingers about one inch to the left or right of your Adam’s apple. It may be helpful to lift your chin when finding the right spot.

n    Never compress both carotid arteries simultaneously.

n    Use your left thumb for right carotid pulse & vice versa.

n    Place tip of thumb b/w larynx & ant.border of sternocleidomastoid.

Evaluation

n    Rate

n    Rhythm

n    Volume

n    Character

n    Vessel wal

The rate: Measure the rate of the pulse (recorded in beats per minute). Count for 30 seconds and multiply by 2 (or 15 seconds x 4). If the rate is particularly slow or fast, it is probably best to measure for a full 60 seconds in order to minimize the impact of any error in recording over shorter periods of time.

1.                 Normal is between 60 and 90. Count the pulse for 1 min / at least 30sec

2.                 Normal : 60 – 90 / min

3.                 Tachycardia : HR > 90/min (Sinus tachycardia, SVT, Paroxysmal atrial tachycardia, atrial tachycardia with fixed block.) Rapid regular pulse : Sinus Tachycardia – Anxiety, emotion, fever, septicaemia with /without fever, pregnancy.

4.                 Bradycardia : HR < 60/min (Sinus bradycardia ( atheletes, sleep, vasovagal episodes, acute.inf.wall MI ) complete heart block)

5.                 Pulse <40/min – Myxodema, heart block, digitalis toxicity

6.                 Marked tachycardia : heart failure, paroxysmal tachycardia, myocarditis, fever, thyrotoxicosis, Tb, sympathomimetics

7.                 Different b/w HR and pulse rate by simultaneous auscultation of heart and palpation of pulse by 2 persons.

The rhythm or regularity: Is the time between beats constant? Normally pulse is regular on palpation. In the normal setting, the heart rate should appear metronomic. Irregular rhythms, however, are quite common. It can be irregular in healthy – Sinus Arrhythmia – acceleration – inspiration slowing down – expiration caused by alterations in vagal tone, children, young adults. If the pattern is entirely chaotic with no discernable pattern, it is referred to as irregularly irregular and likely represents atrial fibrillation. Extra beats can also be added into the normal pattern, in which case the rhythm is described as regularly irregular. This may occur, for example, when impulses originating from the ventricle are interposed at regular junctures on the normal rhythm. If the pulse is irregular, it’s a good idea to verify the rate by listening over the heart. This is because certain rhythm disturbances do not allow adequate ventricular filling with each beat. The resultant systole may generate a rather small stroke volume whose impulse is not palpable in the periphery.

Abnormal Rhythms:

·                    Irregularly irregular – Atrial fibrillation

·                    If irregularity is predictable, as in freq premature ventricular contractions – Regularly irregular pulse.

·                    Extrasystole / ectopic beats : Compensatory pause – hallmark

·                    Atrial Flutter : atrium contracts regularly 250 – 300/min. ventricle contracts much slower rate due to associated AV Block.

·                    Heart Block : pulse – regularly irregular.

·                    Irregularity changes with exertion – extrasystole

·                    Irregularity doesn’t change with exertion – heart block

8.                 The strength: Does the pulse volume (i.e. the subjective sense of fullness) feel normal? This reflects changes in stroke volume. In the setting of hypovolemia, for example, the pulse volume is relatively low (aka weak or thready). There may even be beat to beat variation in the volume, occurring occasionally with systolic heart failure.

9.                 The symmetry

10.            Vessel wall thickness

v         Assess the state of medium sized arteries which are palpable.

v         Method: palpate radial artery with middle 3 fingers.

v         Occlude proximally & with index finger empty artety by pressing out blood distally. Applying pressure on either side – roll the artery over underlying bone using middle finger.

v         Thickness, irregularity & cord like feel – arteriosclerosis – middle size arteries – Monckeberg sclerosis. ( medial coat )

11.            Volume

·                    Amplitude of movement of vessel wall due to passage of pulse wave

·                    Correlates with stroke volume.

·                    High vol – elderly, emotional excitability, anxiety, high C.O states ( thyrotoxicosis, anaemia), sys.htn

·                    Low vol ( pulsus parvus )– shock, low C.O, myocardial ds, valvular ds, pericardial ds, hypovolemia

·                    Lack of rise of post-extrasystolic beat by 10mm Hg / actual fall in pulse – Brockenbrough sign – sign of dynamic obs to lt.ventricular outflow. Eg: HOCM

 

What If I Can’t Find  Pulse?

         Sometimes the pulse is difficult to locate. Here are some tips that might help:

§     Try holding your arm pointing down toward the floor, if you have been holding it up toward your face.

§     Try using your fingertips to feel the pulse instead of laying your fingers across your wrist.

§     Put your fingertips in different places, stopping for about five seconds in each position to try to feel the pulse before moving to another location. Lift, place, and feel; lift, place, and feel, until you find a spot where you can feel the pulsations well.

§     Try varying the pressure of your fingertips on your wrist. You may need to lighten up or press a little harder to feel the pulse.

§     Try these steps on the other wrist.

§     If you still have difficulty, ask a friend to follow the steps and find your pulse.

§     Parenteral medications are given through a route other than the alimentary canal; these routes are intradermal, subcutaneous, intramuscular, or intravenous. The angle of injection and the depth of penetration will indicate the type of injection. Many clients have broadly classified the parenteral route into one category: “injections” or “shots.” The nurse should provide the client with an explanation of the various routes used when administering parenteral drugs. To prepare and administer parenteral medications the nurse must have knowledge of the special equipment, use manual dexterity and sterile technique, and follow Standard Precautions. An injection is an invasive procedure because it breaks the skin barrier. As such, it must be performed using proper aseptic technique to prevent risk of infection.

§     EQUIPMENT

§     Nurses use special equipment such as syringes, needles, ampules, and vials when administering parenteral medications.

 

 

 

§     SYRINGES

§     A syringe has three basic parts: the hub, which connects with the needle; the barrel, or outside part, which contains measurement calibrations; and the plunger, which fits inside the barrel and has a rubber tip (Figure 29-10).

§    

 

§    

§     The nurse must ensure that the hub, inside of the barrel, and shaft and rubber plunger tip are kept sterile. When handling the syringe, the nurse should touch only the outside of the barrel and the plunger’s handle. Most syringes are disposable, made of plastic, and individually packaged for sterility.

§     Disposable syringes are packed I sterile coats

§    

 

§    

 

§    

 

 

Disposable syringes are mainly used nowadays

§     There are several types of syringes, such as the hypodermic, insulin, and tuberculin syringes (Figure 29-11A–C).

 

§    

§     When a medication is incompatible with plastic, it is usually prefilled in a singledose glass syringe.

§    

 

§    

§     Technique of composition of a syringe

§      Syringes are often prepackaged with the commonly used needle size and gauge and are referred to as disposable plastic syringes (Figure 29-11D). The hypodermic syringe comes in 2-, 2.5-, and 3-ml sizes.

§     The measurement calibrations (scales) are usually printed in milliliters and minims. Most syringes are marked in cubic centimeters (cc), and most drugs are ordered in milliters; these are equivalent measurements (1 cc = 1 ml). The hypodermic syringe is used most often when a medication is ordered in milliliters. When the order is written in minims, it is safer to prepare the drug in a tuberculin syringe.

§     The  insulin syringe  is designed specially for use with the ordered dose of insulin.

§    

 

§    

§     Insulin syringe

§     For example, if the health care practitioner writes the order for 30 units of U-100 insulin, the nurse will use an insulin syringe that is calibrated on the 100-unit scale. Insulin syringes are calibrated on the U-100 (100-unit) scale, which is based on 100 units of insulin contained in 1 ml of solution. Insulin syringes come in sizes that hold 0.5 ml (50 units) to 1.0 ml (100 units). Insulin syringes that hold 0.5 ml are the easiest to read and are therefore used for low dosages.

§     There are other sizes of insulin syringes that complement the ordered dose, such as U-30 and U-50, although these dosages are seldom prescribed. The nurse should always compare the size of insulin syringe and the dose indicated on the insulin bottle with the health care practitioner’s order; all three unit doses must be the same.

§     The tuberculin syringe is a narrow syringe, calibrated in tenths and hundredths of a milliter (up to 1 ml) on one scale and in sixteenths of a minim (up to 1 minim) on the other scale.

§    

§     Tuberculin syringe

§      Originally this syringe was designed to administer the tuberculin drug, but it is commonly used today to administer small or precise doses, such as pediatric dosages. The tuberculin syringe should be used for doses 0.5 ml or less.

§     Prefilled single-dose syringes should not be confused with a unit dose. The nurse must be careful to check the prescribed dose against that in the prefilled syringe and discard excess medication. For example, if the health care practitioner orders diazepam (Valium) 5 mg IM as a preoperative sedative and the prefilled single-dose contains 10 mg/2 ml, the nurse must calculate dosage (5 mg/1 ml) and destroy 1 ml from the syringe before administration.

§     NEEDLES

§     Most needles are disposable, made of stainless steel, and individually packaged for sterility. Reusable needles are seldom used, except in certain areas such as surgery and special procedure rooms; reusable needles require frequent inspection to ensure that the needle is sharp, and resterilization is necessary between uses.

§     The needle has three basic parts: the hub, which fits onto the syringe; the cannula, or shaft, which is attached to the hub; and the bevel, which is the slanted part at the tip of the shaft. Needles come in various sizes, from 1/4 inch to 5 inches, and with gauges that range from 28 to 14 (Figure 29-12).

§    

 

§    

 

§     The gauge of the needle refers to the diameter of the shaft; the larger the gauge number, the smaller the diameter of the shaft. Large-gauge needles produce less trauma to the body’s tissue; however, the nurse has to consider the viscosity of a solution when selecting the gauge.

§     The shaft of the needle determines its length. The nurse selects the length of the needle on the basis of the client’s muscle development and weight and the type of injection, such asintradermal versus intramuscular.

§     The needle may have a short or long bevel. The length of bevel selected is based on the type of injection. Long bevels are sharp and produce less pain when injected into the subcutaneous or muscle tissues; however, a short-bevel needle must be used for intradermal and intravenous injections to prevent occlusion of the bevel either by the tissue or by a blood vessel wall. When the nurse removes a needle from its sterile wrapper, the hub of the needle should be immediately attached to the hub of the syringe to prevent contamination. Likewise, the protective cover should remain on the needle’s shaft until the nurse is ready to use the needle. After an injection, the nurse should not recap the needle; used needles should be disposed of in the proper receptacles, such as a sharps container, to prevent needle sticks. See Chapters 31 and 37 for details on how to prevent needlestick injuries. Most agencies have sharps containers in all client care areas.

§     AMPULES AND VIALS

§     Drugs for parenteral injections are sterile preparations. Drugs that deteriorate in solution are dispensed as tablets or powders and dissolved in a solution immediately before injection. Drugs that remain stable in a solution are dispensed in ampules and vials in an aqueous or oily solution or suspension.

§     Ampules are glass containers of single-dose drugs (Figure 29-13).

 

§     The glass container has a constriction in the stem to facilitate opening the ampule.

§     Because many drugs are irritating to the subcutaneous tissue, the nurse should change the needle on the syringe after withdrawing a drug from an ampule. The nurse should consider the use of a needle filter when withdrawing medication from an ampule or vial. Beyea and Nicoll (1996) suggest that the last few drops of the drug be left in an ampule or vial; some studies have found foreign substances, such as glass and rubber, in the containers that could be drawn into the syringe. Glass, single- or multiple-dose rubber-capped drug

§     containers are called vials (Figure 29-16).

§     The vial is usually covered with a soft metal cap that can be easily removed.

§     The nurse should change the needle on the syringe after withdrawing a drug from a vial. Inserting the needle through the rubber cap of the vial can dull the needle or remove the needle coating that helps it glide through the skin.

§     Compatible medications can be mixed in the same syringe. Refer to compatibility charts or check with the pharmacist to determine if the medications can be mixed. If medications are going to be mixed, care must be exercised not to contaminate one medication with the other in their respective vials. See Procedure 29-4 for mixing insulins in one syringe. The nurse must calculate and measure carefully to be sure the final dose is accurate.

§     ANGLE OF INJECTION

§     The angle of insertion depends on the type of injection. Figure 29-18 illustrates the angle of insertion for each type of parenteral injection.

 

 

Intradermal injection

The intradermal route provides a local, rather than systemic, effect and is used primarily for diagnostic purposes such as allergy or tuberculin testing, or for local anaesthetics.

To give an ID injection a 25-gauge needle is inserted at a 10-15° angle, bevel up, just under the epidermis, and up to 0.5ml is injected until a wheal appears on the skin surface. If it is being used for allergen testing, the area should be labelled indicating the antigen so that an allergic response can be monitored after a specified time lapse. The sites suitable for intradermal testing are similar to those for subcutaneous injections but also include the inner forearm and shoulder blades.

When testing for allergies, it is essential to ensure that an anaphylactic shock kit is easily accessible in case the patient develops a hypersensitive reaction.

 

 

 

Subcutaneous injections

The subcutaneous route is used for a slow, sustained absorbtion of medication, up to 1-2ml being injected into the subcutaneous tissue. It is ideal for drugs such as insulin, which require a slow and steady release, and as it is relatively pain free, it is suitable for frequent injections Traditionally, SC injections have been given at a 45° angle into a raised skin fold. However, with the introduction of shorter insulieedles (5, 6 or 8mm), the recommendation for insulin injections is now an angle of 90° . The skin should be pinched up to lift the adipose tissue away from the underlying muscle, especially in thin patients. Some studies using computerised tomography to monitor the destination of the injections, have found that SC injections can be inadvertently administered into muscle, especially in the abdomen and the thigh.

Insulin that is injected into muscle is absorbed more rapidly and can lead to glucose instability and potential hypoglycaemia. Hypoglycaemic episodes may also occur if the anatomical location of the injection is changed, as insulin is absorbed at varying rates from different anatomical sites.

Therefore insulin injections should be systematically rotated within an anatomical site – for example, using the upper arms or abdomen for several months, before there is a planned move elsewhere in the body. When a diabetic patient is admitted to hospital, the current injection area should be assessed for signs of inflammation, oedema, redness or lipohypertrophy, and observations recorded in the nursing notes.

It is no longer necessary to aspirate after needle insertion before injecting subcutaneously. PeragalloDittko (1997) reported studies that found blood was not aspirated prior to SC injection, indicating that piercing a blood vessel in a SC injection was very rare.

Additionally, patient education literature from the manufacturers of insulin devices does not advocate aspiration before injection. It has also beeoted that aspiration before administration of heparin increases the risk of haematoma formation.

 

Sites for subcutaneous injection

 

 

Technique of subcutaneous injection

. 

Insulin is administered with subcutaneous injection into abdominal wall subcutaneous fat

Subcutaneous fat tissue empyema as a complication of injection

Intramuscular injection

Intramuscular injections deliver medication into well perfused muscle, providing rapid systemic action and absorbing relatively large doses; from 1ml in the deltoid site to 5ml elsewhere in adults (these values should be halved for children). The choice of site should take into consideration the patient’s general physical status and age, and the amount of drug to be given. The proposed site for injection should be inspected for signs of inflammation, swelling, and infection, and any skin lesions should be avoided. Similarly, two to four hours after the injection, the site should be checked to ensure there has beeo adverse reaction. If injections are repeated frequently, the sites should be documented to ensure an even rotation. This reduces patient discomfort from overuse of any one area and lessens the likelihood of the development of complications, such as muscle atrophy or sterile abscesses resulting from poor absorbtion.

Older and emaciated patients are likely to have less muscle than younger, more active patients, and therefore the proposed sites should be assessed for sufficient muscle mass. If the patient has reduced muscle mass it is helpful to ‘bunch up’ the muscle before injecting.

tions.

Anatomical landmarks for sites of injetion include:

The deltoid muscle of the upper arm, which is used for vaccines such as hepatitis B and tetanus toxoid.

The dorsogluteal site using the gluteus maximus muscle, the traditional site in the UK. Unfortunately complications are associated with this site as there is a possibility of damaging the sciatic nerve or the superior gluteal artery if the needle is misplaced. Beyea and Nicholl (1995) cited several studies that have used computerised tomography to confirm that even in mildly obese patients, injections into the dorsogluteal area are more likely to be into adipose tissue rather than muscle, and consequently slow the absorbtion rate of the drug.

The ventrogluteal site is a safer option which accesses the gluteus medius muscle. An extensive review of the research into IM injections recommends this site as the primary location for IM injections as it avoids all major nerves and blood vessels and there have beeo reported complications. Additionally, the ventrogluteal site has a relatively consistent thickness of adipose tissue over it: 3.75cm as compared to 1-9cm in the dorsogluteal site, thus ensuring that a standard size 21-gauge (green) needle will usually penetrate the gluteus medius muscle area.

 The vastus lateralis is a quadriceps muscle situated on the outer side of the femur. This site has been the primary site for children, but risks associated with this muscle include accidental injury to the femoral nerve and muscle atrophy through overuse. This site is safe for children up to seven months old, but then the ventrogluteal site is the optimum choice.

 

Location of Deltoid muscle.

The densest part of the muscle can be found by identifying the acromial process and the point on the lateral arm in line with the axilla. The needle should be sited about 2.5cm below the acromial process at 90º. The radial nerve and the brachial artery must be avoided.

Asking patients to put their hand on their hip like a fashion model relaxes the muscle and makes it easier to access (For the gluteus muscles, patients can lie on their side with their knees slightly flexed, or prone with their toes pointing inwards. If the legs are slightly flexed the muscles are more relaxed and the injection is less painful.

Location of dorsogluteal site.

Draw an imaginary horizontal line across from the top of the cleft in the buttocks to the greater trochanter of the femur. Then draw another line vertically midway along the first line, and the location is ‘the upper outer  quadrant of the upper outer quadrant’. That muscle is the gluteus maximus. The superior gluteal artery and  sciatic nerve may be damaged by a poorly located injection. Typical volume is 2-4ml.

Location of ventrogluteal site.

Place the palm of your right hand on the greater trochanter of the patient’s left hip (or your left hand to patient’s right hip). Extend your index finger to touch the anterior superior iliac crest and stretch the middle finger to form a V as far as possible along the iliac crest as you can reach. If you have small hands you may have difficulty reaching the iliac crest, so slide the palm of your hand up from the greater trochanter until you can reach the anterior superior iliac crest with your

index finger. The needle should enter the gluteus medius muscle in the middle of the V at 90º. Typical volume is 1-4ml.

Location of the vastus lateralis and rectus femoris.

In an adult the vastus lateralis can be located by measuring a hand’s breadth laterally down from the greater trochanter, and a hand’s breadth up from the knee, identifying the middle third of the quadriceps muscle as the injection site. The rectus femoris is in the  middle third of the anterior thigh. In children and older people, or emaciated adults, the muscle may need to be bunched up in a  handful to provide sufficient muscle depth. Typical volume 1-5ml, infants 1-3ml

The rectus femoris is the anterior quadriceps muscle which is rarely used by nurses, but is easily accessed for self-administration, or for infants.

Pain

The angle of needle entry may contribute to the pain of the injection. Intramuscular injections should be given at a 90° angle to ensure the needle reaches the muscle, and to reduce pain. Hands positioned near the intended entry site results in fewer needle stick injuries and improves site accuracy.

Therefore, to ensure entry at the right angle, commence the injection with the heel of your palm resting on the thumb of the non-dominant hand, and by holding the syringe between the thumb and forefinger, a firm and accurate thrust of the needle at the correct angle can be achieved.

 

The Z trac

The Z track technique was initially introduced for drugs that stained the skin or were particularly irritant. It is now recommended for use with the full range of IM medications and is believed to reduce pain, as well as the incidence of leakage.

It involves pulling the skin downwards or to one side at the intended site. This moves the cutaneous and subcutaneous tissues by approximately 1-2cm. When identifying the site for injection, it is important to remember that moving the skin may distract you from the intended needle destination.

Therefore, once the surface location has been identified, you need to be able to visualise the underlying muscle that is to receive the injection, and aim for that location, rather than a distinguishing mark on the skin. The needle is inserted and the injection given. Allow ten seconds before removing the needle to allow the medication to diffuse into the muscle. On removal, the retracted skin is released. The tissues then close over the deposit of medication and prevent it from leaking from the site. Exercising the limb afterwards is believed to assist absorbtion of the drug by increasing blood flow to the area.

Air bubble technique

This is a technique that was popular in the US. It arose historically from the use of glass syringes which required an added air bubble to ensure an accurate dose was given. It is no longer considered necessary to allow for the dead space in the syringe and needle, as plastic syringes are calibrated more accurately than glass ones, and it is no longer recommended by manufacturers.

However, two recent studies into depot (oil-based, slow release) injections in the UK compared the

Z track with the air bubble technique, which is also intended to seal the medication in after injection. Air bubble technique is more successful at preventing leakage than the Z track technique.

There are issues related to the accuracy of the dose when using this technique – it may significantly increase the dose.

Although aspiration is no longer recommended for SC injections, it should be practised in IM injections. If a needle is mistakenly placed in a blood vessel, the drug may be given intravenously by mistake and could cause an embolus as a result of the chemical components of the drug. Following insertion into the muscle, aspiration should be maintained for several seconds to allow blood to appear, especially if a narrow bore needle is used. If blood is aspirated, the syringe should be discarded and a fresh drug prepared. If no blood appears, proceed to inject at a rate of approximately 1ml every ten seconds. This may seem slow, but it allows time for the muscle fibres to expand and absorb the solution. There should also be a ten second wait before withdrawal of the needle, to allow the medication to diffuse into the muscle before the needle is finally withdrawn. If there is seepage from the site, slight pressure using a gauze swab can be applied.

A small plaster may be required at the site. Massage of the site should be discouraged because it may cause the drug to leak from the needle entry site and irritate local tissues.

Although it is known that cleansing a site with analcohol-impregnated swab before parenteral injections reduces bacteria, there are inconsistencies in practice. Swabbing before a SC insulin injection predisposes the skin to be hardened by the alcohol. Previous studies suggest that such cleansing is not always necessary and that the lack of skin preparation does not result in infections.

Some trusts now accept that, if the patient is physically clean and the nurse maintains a high standard of hand hygiene and asepsis during the procedure, skin disinfection before an IM injection is not necessary.  skin disinfection is practised, the skin should be cleaned with an alcohol swab for 30 seconds, and then allowed to dry for at least 30 seconds, otherwise it is ineffective. Additionally, if the injection is given before the skin dries, not only does it increase pain for the patient, as the needle entry will make the site sting, the bacteria are not rendered inactive and may be inoculated into the injection site reaches the target muscle. It was found that women had up to 2.5cm more adipose tissue than men in the dorsogluteal site, and therefore a standard 21 by 1.5 inch  gauge needle would only have reached the gluteus maximus muscle in 5 per cent of women and 15 per cent of men.

It is recommended that needles should be changed after drawing up the drug, before the injection, to ensure that it is clean, dry and sharp. However, filter needles are advocated for drawing up medication from a glass vial to avoid potential minute shards of glass from entering the medication. When drawing up medication from plastic ampoules, a blunttipped needle can be used to avoid potential needlestick injuries. A needle that has been blunted by piercing a rubber bung may cause local tissue trauma, and drug contamination during preparation may increase tissue sensitivity, and consequently, pain for the patient.

The syringe size is determined by the amount of fluid required for the drug. For injections less than 1ml, a low dose syringe should be used to ensure an accurate dose. For injections of 5ml or more, it is suggested that the dose should be equally divided between two sites. Note that there are different syringe tip fittings for different applications.

Prepare patients with appropriate information before the procedure, so that they understand what is happening and can comply with instructions

Change the needle after preparation of the drug and before administration to ensure it is clean, sharp and dry, and the right length

Make the ventrogluteal site your first choice, to ensure that the medication reaches the muscle layer (in adults and children over seven months)

Position the patient so that the designated muscle group is flexed and therefore relaxed

If cleaning the skin before needle entry, ensure skin is dry before injecting

Consider using ice or freezing spray to numb the skin before injection, particularly in young children or needle-phobic patients

         Use the Z track technique (Beyea and Nicholl 1995)

         Rotate sites so that right and left sites are used in turn, and document rotation

Enter the skin firmly with a controlled thrust, positioning the needle at an angle as near to 90° as possible, to prevent shearing and tissue displacement

 Inject medication steadily and slowly: about 1ml per ten seconds to allow the muscle to accommodate the fluid

Allow ten seconds after completion of injection to allow the medication to diffuse and then withdraw needle at the same angle as it entered

Do not massage the site afterwards, but be prepared to apply gentle pressure with a gauze swab.

Patients are often afraid of receiving injections because they perceive that it will be painful. The pain of IM injections may be registered in the pain receptors in the skin, or the pressure receptors in the muscle.

Factors which cause pain:

 The needle.

 The chemical composition of the drug or its solution.

 The technique.

 The speed of injection.

 The volume of drug.

The techniques summarised in Box 1 will help to reduce pain.

Patients may have a needle or injection phobia which causes them anxiety, fear and increased pain every time they require an injection.Good technique, appropriate patient information and a calm and confident nurse will help to reduce anxiety. Distraction or behaviour modification techniques may be useful, particularly for long courses of treatment, and the use of needleless systems may reduce needle related anxiety.

It has been suggested that numbing the skin with ice or freezing sprays before inserting the needle may reduce pain,  although this is a technique currently unsupported by research evidence.

Nurses need to be aware that patients may experience syncope or dizziness after a routine injection, even if otherwise apparently fit and well. Ascertaining the patient’s history and usual response to injections, ensuring that the area is safe and that a couch is readily available for them to lie down, will reduce the risk of injury. Experience suggests that those most prone to fainting, though not exclusively, are teenagers and young men

Complications

Complications that occur as a result of infection can be largely prevented by strict aseptic precautions and good hand-washing practice. Sterile abscesses may occur as a result of frequent injections to one site or poor local blood flow. Sites that are oedematous or paralysed will have limited ability to absorb the drug and should not be used.  Careful choice of location will reduce the likelihood of nerve injury, accidental intravenous injection and resultant embolus from the composition of the drug. Systematic rotation of sites will prevent needle myopathy or lipohypertrophy. An appropriate needle size and a preference for the ventrogluteal site, will ensure that the medication is delivered to the muscle, rather than adipose tissue. The use of a Z track technique will reduce pain and the skin staining associated with some drugs.

Once a parenteral drug has been given it cannot be retrieved. The appropriate checks should be made to ensure the drug dose tallies with a valid prescription, and the patient’s identification. Identification of the right patient for the right drug, in the right dose, at the right time, via the right route is essential to prevent medication errors. All drugs should be prepared according to the manufacturer’s instructions, and nurses need to ensure they are aware of the actions, contraindications and side effects of the drug. The nurse should use his or her professional judgement to determine the suitability of the medication for the patient at that time.

Giving an injection safely is considered to be a fundamental nursing activity, and yet it requires knowledge of anatomy and physiology, pharmacology, psychology, communication skills and practical expertise. There is research available to support many current practices and reduce the risks of complications, but there are still areas where evidence to support practice needs to be developed. This article has emphasised the research-based practices that are known, to encourage nurses to incorporate best practice into an everyday procedure.

Technique of intramuscular injection on buttock region

Position of a syringe for intramuscular injection

Technique of intramuscular injection into deltoid muscle

Intravenous injection
Intravenous injecting is a highly efficient way of introducing drugs into the body.

However, when drugs are injected, the filtering and delaying mechanisms that protect us when things are absorbed via the gastro-intestinal tract, lungs or skin are bypassed. The potential for infection and overdose are much increased. 

Correct intravenous injection technique
Many problems can be caused by incorrect injecting technique. Below are some guidelines for a safer and more effective technique of superficial intravenous injecting.

1. Prepare drugs for sole personal use using equipment that is only used by the injector.

2. Identify the vein to be used in some people this is straightforward, others may have to palpate (feel for) veins. Veins feel like a piece of rubber tubing under a sheet.

3. Always inject with the blood flow, i.e. towards the heart.

4. Choose the smallest possible bore and length needle for the site for superficial veins this will be a short orange or brown one.

5. Clean the site with soap and water, or an alcohol swab.

6. Introduce the needle into the vein at a shallow angle, a change in resistance is felt as the needle enters the vein.

7. Pull back the plunger to identify that the needle is in a vein a small amount of dark red venous blood should trickle into the syringe. If a tourniquet is used it should be loosened immediately after accessing the vein.

8. Inject slowly to reduce the likelihood of damage to the vein and to lower the overdose risk. Do not flush out this will significantly increase trauma to the vein.

9. Remove the needle slowly if the needle is removed too quickly, the vein may collapse.

10. Immediately apply pressure to the site bruising is caused by bleeding into the surrounding tissues. Immediate firm pressure will limit the amount of bruising caused.

Sites for intravenous injection

When the arm veins cao longer be used, injectors should consider, and workers should promote, switching to a non-injecting route of drug use.

Irreversible damage to the veins can occur where there is:

§     Repeated use of the same injecting site

§     Poor technique

§     Injection with blunt needles

§     Injection with needles that are too large

§     Injection of irritant substances

Arms
The arms are the site of first choice for intravenous injecting, the superficial veins on the inside of the elbow being the most accessible. Using these sites is least likely to result in inadvertent damage to surrounding tissues and body structures, providing a good hygienic injecting technique is used.

The loss of usable arm veins will leave the injector with stark choices: either to stop injecting and switch to smoking or sniffing, or to move to another site on the body with greater inherent risks.

It is for this reason if no other that injectors should be encouraged to use the least damaging techniques to access veins, in the hope that this will enable them to use their arm veins until such time as they no longer want to inject, or want to stop using drugs entirely. Measures that will help to keep veins and skin healthy include:

§     Washing hands before and after injecting

§     Introducing and removing needles gently

§     Injecting slowly

§     Alternating injection sites, allowing veins to rest and recover

§     Smoking rather than injecting at times in order to rest veins

§     Becoming ambidextrous so that they can inject in both arms it is best to encourage this before the onset of any problems, as it is much easier to practise new techniques when relaxed and the outcome is not crucial

§      Making sure that clients understand the proper use of tourniquets, and release them prior to injecting

§      Staying away from sites that have become infected

§      Using sterile needles and syringes only once.

 

Technique of intravenous injection

Technique of intravenous injection with butterfly nidle

 

Intravenous drop infusion

 

 

Sets for intravenous injection

A dropper

 

 

I/v injection with a thin needle

 

Composition of a set for intravenous drop infusions

 

Infection

Any break in the skin carries a risk of infection. Although IV insertion is an aseptic procedure, skin-dwelling organisms such as Coagulase-negative staphylococcus or Candida albicansmay enter through the insertion site around the catheter, or bacteria may be accidentally introduced inside the catheter from contaminated equipment. Moisture introduced to unprotected IV sites through washing or bathing substantially increases the infection risks.

Infection of IV sites is usually local, causing easily visible swelling, redness, and fever. If bacteria do not remain in one area but spread through the bloodstream, the infection is calledsepticemia and can be rapid and life-threatening. An infected central IV poses a higher risk of septicemia, as it can deliver bacteria directly into the central circulation.

Phlebitis

Phlebitis is inflammation of a vein that may be caused by infection, the mere presence of a foreign body (the IV catheter) or the fluids or medication being given. Symptoms are warmth, swelling, pain, and redness around the vein. The IV device must be removed and if necessary re-inserted into another extremity.

Due to frequent injections and recurring phlebitis, scar tissue can build up along the vein. The peripheral veins of intravenous drug addicts, and of cancer patients undergoing chemotherapy, become sclerotic and difficult to access over time, sometimes forming a hard “venous cord”.

Infiltration / Extravasation

Infiltration occurs when an IV fluid or medication accidentally enters the surrounding tissue rather than the vein. This occurs more frequently with chemotherapeutic agents and people who have tuberculosis. It is also known as extravasation (which refers to something escaping the vein). It may occur when the vein itself ruptures (the elderly are particularly prone to fragile veins due to a paucity of supporting tissues), where the vein is damaged during insertion of the intravascular access device or the device is not sited correctly or where the entry point of the device into the vein becomes the path of least resistance (e.g. if a cannula is in a vein for some time, the vein may scar and close and the only way for fluid to leave is along the outside of the cannula where it enters the vein). It is characterized by coolness and pallor to the skin as well as localized swelling or edema. It is usually not painful. It is treated by removing the intravenous access device and elevating the affected limb so that the collected fluids can drain away. Sometimes injections of hyaluronidase can be used to speed the dispersal of the fluid/drug. Infiltration is one of the most common adverse effects of IV therapy and is usually not serious unless the infiltrated fluid is a medication damaging to the surrounding tissue, in which case extensive necrosis can occur.

Fluid overload

This occurs when fluids are given at a higher rate or in a larger volume than the system can absorb or excrete. Possible consequences include hypertension, heart failure, and pulmonary edema.

Effects of hypothermia and the exacerbation of cold intravenous fluid

Hypothermia

The human body is at risk of accidentally induced hypothermia when large amounts of cold fluids are infused. Rapid temperature changes in the heart may precipitate ventricular fibrillation.

Electrolyte imbalance

Administering a too-dilute or too-concentrated solution can disrupt the patient’s balance of sodium, potassium, magnesium, and otherelectrolytes. Hospital patients usually receive blood tests to monitor these levels.

Embolism

A blood clot or other solid mass, as well as an air bubble, can be delivered into the circulation through an IV and end up blocking a vessel; this is called embolism. Peripheral IVs have a low risk of embolism, since large solid masses cannot travel through a narrow catheter, and it is nearly impossible to inject air through a peripheral IV at a dangerous rate. The risk is greater with a central IV.

Air bubbles of less than 30 microliters are thought to dissolve into the circulation harmlessly. Small volumes do not result in readily detectable symptoms, but ongoing studies hypothesize that these “micro-bubbles” may have some adverse effects. A larger amount of air, if delivered all at once, can cause life-threatening damage to pulmonary circulation, or, if extremely large (3-8 milliliters per kilogram of body weight), can stop the heart.

One reason veins are preferred over arteries for intravascular administration is because the flow will pass through the lungs before passing through the body. Air bubbles can leave the blood through the lungs. A patient with a heart defect causing a right-to-left shunt is vulnerable to embolism from smaller amounts of air. Fatality by air embolism is vanishingly rare, although this is in part because it is so difficult to diagnose.