OXYGENATION
Oxygenation (the delivery of oxygen to the body’s tissues and cells), is necessary to maintain life and health.
Clients with compromised oxygenation status need careful assessment and thoughtful nursing care to achieve an adequate and comfortable level of oxygenation function.
The purpose of this chapter is to explore the elements of the process of oxygenation, common mechanisms by which it may be impaired, and interventions that are aimed at improving oxygen delivery to the cells.
PHYSIOLOGY OF OXYGENATION
The delivery of oxygen to the body’s cells is a process that depends upon the interplay of the pulmonary, hematologic, and cardiovascular systems. Specifically, the processes involved include ventilation, alveolar gas exchange, oxygen transport and delivery, and cellular respiration. The basic anatomy of the lungs is shown in Figure 32-1.
Ventilation
The first step in the process of oxygenation is ventilation, which is the movement of air into and out of the lungs for the purpose of delivering fresh air into the lung’s alveoli (Figure 32-2). Ventilation is regulated by respiratory control centers in the pons and medulla oblongata, which are located in the brain stem. The rate and depth of ventilation are constantly adjusted in response to changes in the concentrations of hydrogen ion (pH) and carbon dioxide (CO2) in the body’s fluids.
For instance, an increase in carbon dioxide in the blood or a decrease in pH in the body’s fluids will stimulate faster and deeper ventilation. A decrease in blood oxygen concentration (hypoxemia) will also stimulate ventilation, but to a lesser degree.
Inhalation of air is initiated when the diaphragm contracts, pulling it downward and thus increasing the size of the intrathoracic space (Figure 32-3). This space is also increased by contraction of the external intercostal muscles, which elevate and separate the ribs and move the sternum forward. The effect of increasing the space inside the thorax is to decrease the intrathoracic pressure, so that air will be drawn in from the atmosphere.
Stretch receptors in the lung tissue send signals back to the brain to cause cessation of inhalation, preventing overdistension of the lungs. Exhalation occurs when the respiratory muscles relax, thus reducing the size of the intrathoracic space, increasing the intrathoracic pressure, and forcing air to exit the lungs. Under normal conditions, exhalation is a passive process.
When the movement of air is impeded, additional muscles may be used to increase the ventilatory ability.
These accessory muscles of ventilation include the sternocleidomastoid muscle, the abdominal muscles, and the internal intercostal muscles. In some disease states, exhalation is impaired, requiring that the individual actively force air out of the lungs rather than passively exhaling. Forced expiration is aided by the intercostal muscles and the abdominal recti. When additional muscular force is required for breathing, the work of breathing is said to be increased.
Several mechanisms exist to keep the airways clear of microorganisms and debris. As air is inhaled through the nose, the larger particles are filtered out through hairs lining the nasal passages. The mucous membranes of the nasopharynx and sinuses warm and humidify the inspired air, and the film of mucus lining these membranes traps smaller particles. Closure of the glottis protects the airway from aspiration of food and fluids during swallowing. In the trachea and larger bronchi, tiny hairlike cilia continually produce wavelike movements to propel mucus and particles upward, where they can be coughed out. If any invaders manage to reach the alveoli, specialized alveolar macrophages will engulf and destroy the offending organism. Disease processes can interfere with any of these protective mechanisms, increasing the individual’s vulnerability to infection and injury.
Alveolar Gas Exchange
Once fresh air reaches the lung’s alveoli, the next step in the process of oxygenation begins. The exchange of oxygen from the alveolar space into the pulmonary capillary blood is referred to as oxygen uptake; it may also be called external respiration. Oxygen diffuses across the alveolar membrane in response to a concentration gradient; that is, it moves from an area of higher concentration (the alveoli) to an area of lower concentration (the pulmonary capillary blood), seeking equilibrium. At the same time, carbon dioxide diffuses from the blood to the alveolar space, also in response to a concentration gradient (Figure 32-4).
Oxygen Transport and Delivery
Oxygen Transport in the Blood
Once the diffusion of oxygen across the alveolarcapillary membrane occurs, the oxygen molecules are dissolved in the blood plasma. Three factors influence the capacity of the blood to carry oxygen: the amount of dissolved oxygen in the plasma, the amount of hemoglobin, and the tendency of the hemoglobin to bind with oxygen. However, the plasma is not able to carry nearly enough dissolved oxygen to meet the metabolic needs of the body. The oxygen-carrying capacity of the blood is greatly enhanced by the presence of hemoglobin in the erythrocytes.
The amount of oxygen carried in a sample of blood is measured in two ways. Oxygen dissolved in plasma is expressed as the partial pressure of oxygen (PaO2). The normal PaO2 in arterial blood is about 80 to
Hemoglobin molecules have the ability to form a reversible bond with oxygen molecules, so that the hemoglobin readily takes up oxygen in the lungs, while it also readily releases oxygen to the body’s cells in the systemic capillary beds. This seemingly paradoxical shift in hemoglobin’s affinity for oxygen is represented by the oxyhemoglobin dissociation curve, which is a graphic representation of the relationship between the partial pressure of oxygen and oxygen saturation.
The affinity of hemoglobin for oxygen is highest when the PaO2 (the measure of oxygen dissolved in the arterial blood plasma) is
As the oxygen-saturated blood is circulated to the peripheral capillary beds, dissolved oxygen diffuses out of blood. This decrease in dissolved oxygen causes hemoglobin to lose its affinity for oxygen, so the oxygen is then released to the body’s cells. Once the partial pressure of oxygen in the blood drops below
Several physiological factors may alter the affinity of hemoglobin for oxygen, and these shifts can be represented on the oxyhemoglobin dissociation curve. A shift to the left occurs when affinity is increased so that, for a given PaO2, the associated SaO2 will be higher. This means that, although the arterial blood may be carrying adequate oxygen, little of it is being released to the tissues.
A shift to the left may be caused by increased pH (alkalosis), hypothermia, or a decrease in the red blood cell enzyme 2,3-diphosphoglycerate (2,3-DPG), which may occur after massive transfusions of banked blood.
A shift to the right of the oxyhemoglobin dissociation curve means that, for a given PaO2, the SaO2 will be lower. This phenomenon represents a decreased affinity of hemoglobin for oxygen so that oxygen is more readily released to the tissues. This shift occurs in response to acidosis, hyperthermia, and hypoxia (which induces increased production of 2,3-DPG) and results in improved delivery of oxygen to the tissues.
Circulation
Once oxygen is bound to hemoglobin, the oxygen is delivered to the cells of the body by the process of circulation.
Circulation of the blood is the function of the heart and blood vessels.
The heart is a muscular pump that is divided into four chambers: the right and left atria and the right and left ventricles (Figure 32-6). A series of valves allows for unidirectional blood flow through the chambers, which is driven by the sequential contraction and relaxation of the heart muscle.
A single cycle of atrial and ventricular contraction and relaxation is referred to as a cardiac cycle, which is the product of the interplay of electrical and mechanical events. The electrical activity of the heart involves the generation and transmission of electrical current by specialized cardiac cells known as the cardiac conduction system (Figure 32-7). A small mass of cells in the right atrium, the sinoatrial node, or SA node, normally controls the heart rate by rhythmically generating electrical impulses. For this reason, the SA node is often referred to as the heart’s “pacemaker.” The impulses created by the SA node travel along specialized internodal pathways to spread throughout the atria, resulting in mechanical muscular contraction. The electrical activity is then transmitted down to the ventricles via the atrioventricular (AV) node and spreads through the ventricular tissue along the bundle of His, right and left bundle branches, and Purkinje fibers. Again, the result is muscular contraction. The sequential contraction and relaxation of the atria and ventricles is an essential factor in the cyclical filling and emptying of the chambers, which produce circulation.
The process of chamber filling is referred to as diastole, and the process of a chamber emptying is systole.
Atrial diastole occurs as the right and left atria relax and blood flows into the right and left atrial chambers from the venae cavae and pulmonary veins, respectively. As pressure rises in the atria, the atrioventricular valves (the mitral and tricuspid) open, permitting the blood to begin flowing into the ventricles. Ventricular filling is further augmented by contraction of the atrial muscle (atrial systole), forcing additional blood into the ventricles.
This contribution to ventricular filling is sometimes called “atrial kick.”
Filling of the ventricles causes the intraventricular pressure to rise. When the intraventricular pressure exceeds the pressure in the atria, the atrioventricular valves close. The ventricular muscle then begins to contract, further increasing intraventricular pressure until it is sufficient to force open the two semilunar valves (the pulmonic and aortic valves). As contraction of the ventricular walls proceeds, blood is forced out of the ventricles and into the circulation (ventricular systole).
Blood leaving the right ventricle is pumped into the pulmonary artery, which quickly branches into right and left pulmonary arteries. Further division of the pulmonary arterial tree culminates in the pulmonary capillary bed. Blood in the pulmonary capillaries is in very close contact with the alveolar air; it is here that alveolar-capillary gas exchanges take place. From the pulmonary capillaries, the freshly oxygenated blood flows into the pulmonary veins and to the left atrium, which delivers it to the left ventricle (Figure 32-8).
Blood leaving the left ventricle enters the aorta. The aorta serves as the “trunk” of the arterial tree, with branches leading to every organ and tissue group in the body. Blood flow through the arterial system is driven by the pressure generated during ventricular systole and is influenced by the volume and viscosity of the blood and the amount of resistance within the arterial system.
Blood flow to specific organs and tissues may be increased or reduced by the relaxation or contraction of precapillary sphincters, which are rings of smooth muscle surrounding the arterioles. This mechanism allows for redistribution of blood flow to the areas of greatest need, a process known as autoregulation.
Blood return through the venous system is also driven by pressure gradients, although the venous system operates under lower pressure than the arterial system does. In order to boost venous return, many veins (particularly in the lower extremities) are equipped with valves that prevent backward flow of blood (regurgitation); as the veins are compressed by their surrounding skeletal muscles, blood is forced along toward the vena cava and ultimately to the right atrium.
Cellular Respiration
Gas exchange at the cellular level, like that at the alveolar level, takes place via diffusion in response to concentration gradients. Oxygen diffuses from the blood to the tissues, while carbon dioxide moves from the tissues to the blood; the blood is then reoxygenated by the heart. This process is referred to as internal respiration.
FACTORS AFFECTING OXYGENATION
Adequate oxygenation is influenced by many factors, including age, environmental and lifestyle factors, and disease processes.
Age
Oxygenation status can be influenced by age. Older adults may exhibit a barrel chest and require increased effort to expand the lungs. Loss of alveolar gas exchange is accompanied by a decrease in the partial pressure of oxygen. Older adults are also more susceptible to respiratory infection because of decreased activity in the cilia, which normally are an effective defense mechanism.
Environmental and Lifestyle Factors
Environmental and lifestyle factors can significantly affect a client’s oxygenation status. Clients who are exposed to dust, animal dander, asbestos, or toxic chemicals in the home or workplace are at increased risk for alterations in oxygenation. Individuals who experience significant physical or emotional stress or who are obese or underweight are also subject to changes in oxygenation status. Smokers and those exposed to second-hand smoke should be questioned as to the type and amount of tobacco and number of years of exposure.
Disease Processes
Oxygenation alterations can often be traced to disease states related to alterations in ventilation, alveolar gas exchange, oxygen uptake, or circulation. There are many disease states that may affect oxygenation, including obstructive pulmonary disease, restrictive pulmonary disease, diffusion defects, ventilation-perfusion mismatching, atherosclerosis, heart failure, anemia, and alterations in oxygen uptake.
Obstructive Pulmonary Disease
Alterations in ventilation may be related to obstructive or restrictive pulmonary disease. Obstructive pulmonary disease occurs when the airways become partially or completely blocked, diminishing airflow, or the lungs lose some of their elastic recoil, trapping stale air, which should be exhaled. In both cases, the end result is impaired exhalation, air trapping, and difficulty bringing fresh air into the alveoli (Figure 32-9). The most common obstructive pulmonary diseases are asthma, emphysema, and chronic bronchitis, collectively known as chronic obstructive pulmonary disease (COPD).
Restrictive Pulmonary Disease
Restrictive pulmonary disease represents pathologies that impair the ability of the chest wall and/or lungs to expand during the inspiratory phase of ventilation. This impairment increases the work of breathing and also reduces airflow to the alveoli. A wide variety of disorders cause restrictive lung disease, including pneumonia and pulmonary fibrosis (scarring).
Traumatic injury to the thorax or a break in the pleural membrane that surrounds the lungs may also produce restrictive pulmonary dysfunction. The stability of the chest depends upon the rib cage; multiple rib fractures may produce a type of paradoxical chest wall movement called “flail chest” that impedes normal airflow. The dual-layer pleural membrane also has an important structural function; it helps maintain a negative pressure between its two layers that keeps the lungs from collapsing upon themselves. A break in either layer of the membrane or an abnormal collection of fluid between them interferes with this function, permits alveoli to collapse, and increases the work of breathing. Common pleural defects are described in Table 32-1.
Alveolar collapse, known as atelectasis, can be caused by pleural defects as described above, by compression from a mass such as a tumor, or by occlusion of the small airways by secretions, which prevents air movement into the associated alveoli. Failure of a client to breathe deeply after abdominal surgery may result in atelectasis. Regardless of the cause, atelectasis results in restrictive pulmonary dysfunction and reduces the amount of alveolar-capillary surface area engaged in gas exchange.
Diffusion Defects
Another mechanism of oxygenation impairment is a decrease in the efficiency of gas diffusion from the alveolar space into the pulmonary capillary blood, known as a diffusion defect. This may be caused by thickening of the alveolar-capillary basement membrane or by marked increases in the speed of blood flow through the pulmonary capillary beds, which reduce contact time with the alveoli. Diffusion defects by themselves are uncommon but may coexist with obstructive or restrictive pulmonary disease such as emphysema, pulmonary edema, or fibrosis.
Ventilation-Perfusion Mismatching
Gas exchange across the alveolar-capillary membrane is also influenced by ventilation-perfusion (V/Q) mismatching, or the balance between ventilation and perfusion.
The amount of fresh air entering the alveoli (alveolar ventilation) and the amount of blood flow to various regions of the pulmonary capillary network (perfusion) are not uniform throughout the lungs. Due to alterations in position and the effect of gravity, certain zones of lung tissue may have better ventilation or perfusion than others at any given time.
An important mechanism of compensation in healthy lung tissue is to produce vasoconstriction or bronchoconstriction as needed to better match ventilation to perfusion or vice versa. Many disease states, however, produce areas of ventilation-perfusion mismatching that cannot be overcome by compensatory responses. When mismatching occurs, some alveolar regions will be well ventilated but poorly perfused (a condition known as deadspace), while others may be well perfused but poorly ventilated (known as shunting). This phenomenon is illustrated in Figure 32-10.
Alterations in circulation may occur in either the pulmonary or the systemic vasculature and may be localized or generalized. Generalized decreases in pulmonary circulation may be caused by right-sided heart failure or by pathologies in the pulmonary vascular system such as pulmonary hypertension and the resultant pulmonary artery sclerosis. Regional decreases in pulmonary circulation may be related to blockage of a pulmonary artery by an embolus or by regional vasoconstriction.
Atherosclerosis
Alterations in systemic circulation may also be generalized or localized. A common cause of altered arterial circulation is atherosclerosis. This disease is characterized by narrowing and eventual occlusion of the lumen (opening of the arteries) by deposits of lipids, fibrin, and calcium on the interior walls of the arteries (Figure 32-11). The reduction in blood flow with accompanying oxygen deprivation leads to ischemia (deprivation of blood flow) and eventual infarction (necrosis or death) of the affected tissue.
Atherosclerosis in the coronary arteries (coronary heart disease) and the arteries of the brain (cerebral vascular disease) causes myocardial infarction and stroke, respectively, two of the leading causes of death in our society.
Heart Failure
Generalized decreases in tissue perfusion may be caused by left-sided heart failure or by loss of circulating blood volume as may occur with shock or hemorrhage. Heart failure is a condition in which the heart is unable to pump enough blood to meet the metabolic needs of the body; typically, this is accompanied by a backup of blood in the venous circuits (pulmonary and systemic veins), leading to the condition known as congestive heart failure. The increased pressure of the blood in the engorged veins causes fluid to leak out of the associated capillary beds, causing edema in the tissue, including the lungs (pulmonary edema).
Congestive heart failure results in poor arterial perfusion to the body’s tissues. This reduction in cardiac output (amount of blood pumped by the heart) may be mild, causing only vague symptoms, or may be profound enough to cause death. Causes of congestive heart failure include myocardial infarction, hypertensive heart disease, and valvular disorders, among others.
Loss of circulating blood volume (hypovolemia) may result from massive bleeding, loss of fluid through a wound (such as an extensive burn injury), or severe dehydration.
Anemia
Another factor that influences oxygenation is the amount of hemoglobin in the blood available to bind with oxygen. A deficiency of hemoglobin (anemia) may decrease the oxygen-carrying capacity of the blood. A person who is anemic may have normal SaO2 levels but still continue to experience inadequate tissue oxygenation at the cellular level. Certain poisoning syndromes, most notably carbon monoxide poisoning, mimic anemia in that they reduce oxygenation by competing with oxygen for binding sites on the hemoglobin molecule.
Alterations in Oxygen Uptake
A final factor to consider in the process of oxygenation involves the uptake of oxygen by the body’s cells.
Certain conditions may impair the cells’ ability to take up and utilize oxygen, particularly when the mitochondria are damaged. Cyanide poisoning and severe sepsis impair mitochondrial functioning, rendering the oxygen in arterial blood useless to the cells.
Physiological Responses to Reduced Oxygenation
When oxygen delivery is inadequate to meet the metabolic needs of the body, various responses to this deficit can be expected, including changes in metabolic pathways and efforts to increase the extraction of available oxygen. If these efforts fail, cells will be damaged and ultimately die.
Increased Oxygen Extraction
Under normal conditions, the cells of the body do not extract all of the oxygen carried in the arterial blood. In fact, blood returning to the heart via the venous circulation is typically about 75% saturated with oxygen. In response to poor oxygen delivery or increased oxygeeed, the cells can extract more oxygen from the arterial blood.
Anaerobic Metabolism
The utilization of food (glucose) for cellular energy occurs via metabolic pathways that use oxygen; this is known as aerobic metabolism. Many cells are also capable of utilizing alternate metabolic pathways in the absence of oxygen for short periods of time; this is referred to as anaerobic metabolism. Anaerobic metabolism is limited by several factors:
1. Not all cells are capable of significant anaerobic metabolism (most notably brain cells).
2. Anaerobic metabolism yields less energy per unit of fuel than does aerobic metabolism.
3. Anaerobic metabolism results in the accumulation of acid byproducts, such as lactate, which upset the chemical environment of the cell and induce the release of cell-damaging (lysosomal) enzymes.
Tissue Ischemia and Cell Death
Prolonged oxygen deprivation (hypoxia) will lead to a syndrome ending in cellular death. The decreased production of adenosine triphosphate (ATP) resulting from anaerobic metabolism reduces the amount of energy available for cellular metabolic functions and results in a breakdown in all cellular functions. The integrity of the cell membrane becomes impaired, and the cell begins to swell. Cellular organelles may become damaged and lysosomal enzymes released, killing the cell. The destruction of tissues or organs as a result of oxygen deprivation is known as an infarction.
Widespread cellular death resulting from oxygenation disturbances is the underlying characteristic of a devastating syndrome known as multiple-organ-system failure.
Carbon Dioxide Transport and Excretion
Carbon dioxide is a natural byproduct of glucose metabolism. Like oxygen, it exists normally as a gas and can be dissolved in the plasma as well as loosely bound to the hemoglobin molecule (although carbon dioxide attaches to a different binding site on the hemoglobin molecule than does oxygen). In the lungs, carbon dioxide is released into the alveoli by diffusion, and when the individual exhales, the carbon dioxide exits to the atmosphere.
In the body fluids, carbon dioxide functions as an acid because, combined with water, it produces carbonic acid. The hydrogen ions that are liberated in this process stimulate the respiratory control centers in the pons and medulla to increase the rate and depth of breathing; more carbon dioxide is then released by the lungs and the pH of the body is brought back to normal. Likewise, increased production of carbon dioxide, as may be associated with fever or exercise, is often a cause of increased ventilatory rate (tachypnea) and depth. Elevated blood levels of carbon dioxide (hypercapnea) indicate inadequate alveolar ventilation.
ASSESSMENT
Health History
The health history of the individual experiencing oxygenation deficits is important in the development of the plan of care. The health history should begin with a thorough exploration of the presenting problem (Table 32-2), including how long it has been present and whether it has recently gotten worse, then should proceed to explore the medical history, impact of the illness on activities of daily living, and the client’s knowledge level and coping abilities.
Physical Examination
Inspection will begin when the nurse first encounters the client. This is a time to make general notes of the client’s efforts at ventilation, especially anxious or distressed appearance, flaring of nostrils, position preferences, and general chest configuration (Figure 32-12). While counting the respiratory rate, also note the rhythm or pattern of the breathing for regularity or irregularity (Figure 32-13). The signs and symptoms of hypoxia are relative to the onset. Early clinical manifestations of hypoxia include restlessness, apprehension, anxiety, dizziness, inability to concentrate, confusion, agitation, increased pulse rate, increased rate and depth of respiration, and elevated blood pressure (unless the hypoxia is caused by shock). If the hypoxia goes untreated, the respiratory rate may decline and changes in the level of consciousness progress to stupor, or coma indicating ischemia of neuronal cells resulting from oxygen deprivation.
Perfusion deficits resulting in poor circulation can be visually noted in mottled skin, cyanosis (bluish coloration of the skin), and edema. The bluish discoloration of cyanosis is the result of the presence of desaturated hemoglobin in capillaries that may occur from either hypoxia or stagnant blood flow. When cyanosis is observed in the tongue, soft palate, and conjunctiva of the eye, it indicates hypoxemia, whereas cyanosis of the extremities, nail beds, and earlobes is often a result of vasoconstriction and stagnant blood flow.
Clubbing of the fingers, which manifests as a flattened angle of the nailbed and a rounding of the fingertips, is a sign of chronic hypoxia (Figure 32-14).
Common palpation findings related to compromised ventilation include vocal fremitus and displacement of the trachea. Perfusion deficits are noted in changes in pulse rate or character, clammy skin, and ulcers in the lower extremities.
Percussion may reveal hyperresonance, dull percussion tone, or changes in the density of the lungs and surrounding tissues.
Auscultation may reveal adventitious breath sounds such as rales (crackles) or wheezes (rhonci), pleural friction rub, or stridor, all indicators or alterations in ventilation (Table 32-3). Circulation deficits will be noted upon auscultation by gallops, or extra heart sounds, and murmurs, or sounds produced by blood flowing through a malfunctioning valve.
Diagnostic and Laboratory Data
There are many tests to measure oxygenation status.
Pulse oximetry uses light waves to measure oxygen saturation (SaO2) noninvasively (Figure 32-15). Arterial blood gases (ABGs) measure a number of indicators that can affect oxygenation status; these factors and their values are listed in Table 32-4. Sputum collection is another valuable tool in assessing a client’s oxygenation functioning; this procedure is outlined in Table 32-5, and common findings and their indications are listed in Table 32-6. Measurements of lactic acid, hemoglobin, and hematocrit are also useful in determining the effectiveness of the body’s oxygen delivery to tissues.
Selected tests to determine oxygenation status are discussed in Table 32-7. (See also Figure 32-16 for ventilatory function.) Clients undergoing these tests are often apprehensive and need nursing care and education directed at their knowledge levels.
NURSING DIAGNOSIS
Nursing care of the client experiencing oxygenation problems should be prioritized on the basis of the ABC format used in basic life support; that is, consider the airway, breathing, and circulation first and foremost.
The primary nursing diagnoses are related to these priorities.
Ineffective Airway Clearance
Ineffective airway clearance exists when the client has difficulty maintaining a patent (open) airway at any point along the airway. This occlusion of the airway may be partial or complete. Causes of ineffective airway clearance include:
• Obstruction of the airway by the tongue (as may occur in the comatose or anesthetized client)
• Obstruction of airway by secretion (as may occur with excessive sputum production, and ineffective or absent cough)
• Upper airway obstruction caused by edema of the larynx or glottis
• Obstruction of the trachea or a bronchus by foreign body aspiration
• Partial occlusion of the bronchi and bronchioles by infection (bronchitis, bronchiolitis), inflammation and smooth muscle spasm (asthma), or occlusion or compression by a tumor mass
• Occlusion of the more distal airways by the changes associated with emphysema
Assessment findings in the client with ineffective airway clearance include a complaint of feeling short of breath or suffocating, a condition sometimes referred to as “air hunger.” The use of accessory muscles of ventilation may be noted, and the client may complain of fatigue. Shortness of breath may be noted on observation, and the client may have difficulty speaking because of it. A cough may be noted, and on auscultation rales and rhonchi may be heard. Poor aeration of the alveoli, as can occur with emphysema and severe asthma, will cause diminished breath sounds over the peripheral lung fields. Complete obstruction of a large or mediumsized airway will result in a loss of breath sounds over the affected lung segment.
Ineffective Breathing Patterns
Ineffective breathing pattern is commonly a problem for clients with restrictive pulmonary disease or central nervous system disorders that affect breathing. Those with restrictive pulmonary disease, in an effort to decrease their work of breathing, tend to adopt a pattern of rapid, shallow respirations. This respiratory pattern does not deliver adequate fresh air to the alveoli, resulting in chronic air hunger while contributing to muscle fatigue. Central nervous system disorders, including the effects of anesthetics and narcotics, may reduce both the rate and the depth of ventilation.
Lesions affecting the brain stem in particular may reduce ventilation to dangerous levels.
Another group of clients at risk for ineffective breathing patterns are those who have had major abdominal or thoracic surgery or whose mobility is restricted.
These individuals have a tendency to take shallow breaths and to avoid sighing and coughing, both necessary to maintain airway integrity.
Neuromuscular diseases that weaken the respiratory muscles may also result in ineffective breathing patterns as well as impaired airway clearance. Examples of such disorders include Guillian-Barré syndrome and myasthenia gravis. Alterations in thoracic structures that interfere with breathing patterns include abnormal curvatures of the spine (scoliosis, kyphosis), chest wall injury, and pleural defects.
Impaired Gas Exchange
Impaired gas exchange occurs when, despite the delivery of fresh air to the alveoli, adequate oxygen does not enter the arterial blood and/or carbon dioxide is not removed from the venous blood. Often this condition is the result of ventilation-perfusion mismatching or overall decreases in the amount of alveolar-capillary surface area available for gas exchange, a characteristic of emphysema. Another cause of impaired gas exchange is widespread shunting, as may occur with atelectasis (alveolar collapse) and pneumonia.
Impaired gas exchange is assessed by measuring the oxygen and carbon dioxide content in the arterial blood via arterial blood gas analysis or pulse oximetry or both.
Decreased Cardiac Output
Decreased cardiac output impairs oxygen delivery to the tissues and may also be a factor in impaired gas exchange, as when congestive heart failure causes pulmonary edema. Causes of decreased cardiac output include heart failure and various types of shock. The assessment findings associated with decreased cardiac output may include low blood pressure; cool, clammy skin; weak, thready pulses; low urine output; and a diminished level of consciousness. If pulmonary edema is present, crackles will be heard over the lung bases and the client may produce frothy pink or white sputum.
Ineffective Tissue Perfusion
Ineffective (decreased) tissue perfusion may be widespread, as in the case of decreased cardiac output, or it may be confined to one or more tissues or organs of the body.
A common cause of regional decreases in tissue perfusion is atherosclerosis, which may impair perfusion to the heart, brain, kidneys, or extremities. Assessment findings depend upon the organ or tissue involved, but one common finding is pain. The tissue that is deprived of oxygen will in many cases be painful, as the accumulation of lactic acid and the chemical mediators of the inflammatory response stimulate local pain receptors.
Other Nursing Diagnoses
The relationship between the primary nursing diagnoses discussed above and the secondary nursing diagnoses in the client with oxygenation problems is reciprocal; that is, the primary diagnoses both influence and are influenced by the secondary diagnoses. A holistic approach to nursing care requires that all diagnoses affecting the patient be considered and prioritized in developing the plan of care.
Deficient Knowledge
Deficient knowledge may exist to varying degrees in the client with either acute or chronic oxygenation problems.
Involving the client in the plan of care requires that the client be informed regarding the disease process, diagnostic procedures, and treatment modalities.
Assessment for deficient knowledge involves questioning the client and family with regard to their understanding and perceptions of these subjects. It is a mistake to assume that a client with a long-standing chronic illness has a good understanding of that illness.
Activity Intolerance
Activity intolerance reflects the impact of the illness on the client’s ability to perform activities of daily living; the degree of this impairment may range from mild to severe, but it is important that this judgment be based on the client’s, not the nurse’s, perception of the activity intolerance. Activity restrictions that may be a mere annoyance for one individual can be viewed as catastrophic by another.
To assess activity intolerance, both interview and observation are useful. Ask the client to compare the current level of activity with the previous level and desired level. In addition, observe the client performing activities such as moving about in bed, ambulating, and performing personal care activities; note the point at which fatigue and/or dyspnea occurs and the amount of rest required. Objective tests of exercise tolerance, such as stress tests, may be performed in certain cases.
Disturbed Sleep Pattern
Disturbed sleep pattern is common in people with both cardiac and pulmonary disease. As mentioned earlier, many people with restrictive and obstructive pulmonary diseases find that breathing is easiest in an upright position; this position is also more comfortable for those with congestive heart failure. Sudden attacks of dyspnea during sleep, called paroxysmal nocturnal dyspnea, may interrupt the sleep of these clients, resulting in chronic fatigue. Complaints of poor sleep, along with daytime sleepiness and fatigue, are common assessment findings.
Severe sleep deprivation can result in personality changes, hallucinations, and delusions.
A particular sleep problem associated with airway obstruction is sleep apnea. It is often seen in males who are overweight and have short, thick necks and is commonly associated with loud, heavy snoring. The soft tissues of the upper airways collapse during sleep, resulting in periods of absence of breathing (apnea).
The individual then rouses enough to resume breathing, interrupting the normal sleep cycle. These individuals may complain of persistent daytime fatigue despite what seems to be adequate nighttime sleep.
Imbalanced Nutrition
Nutritional alterations are also commonly associated with both cardiac and pulmonary disease. The client with dyspnea may have difficulty consuming adequate food because of the effort involved; in turn, the malnutrition contributes to respiratory muscle weakness.
The client with a productive cough may have an unpleasant taste in the mouth, interfering with appetite. Congestive heart failure may cause a poor appetite (anorexia) because of decreased perfusion to the gut. On the other hand, obesity can affect oxygenation by increasing the work of breathing as well as the cardiac workload.
Acute Pain
Acute pain may be present in the client with ischemia to the heart or to the extremities due to inadequate perfusion; chest wall or pleuritic pain may also be a feature of many pulmonary disorders. Adequate pain control can influence the effectiveness of breathing patterns and coughing, making pain control a priority in these cases. Pain assessment should address the nature of the pain, its intensity, its location and radiation, factors that make it better or worse, and any associated symptoms. For instance, pain caused by myocardial ischemia is called angina pectoris and is often described as crushing or squeezing iature; it may be confined to the chest or it may radiate to the neck, shoulder, jaw, arm, or hand. Ischemia to the extremities (most often the legs) produces a pain known as intermittent claudication, which is typically brought on by exercise and relieved by rest.
Anxiety
Anxiety is often a prominent finding in individuals who are experiencing breathing difficulties or acute cardiac problems, such as chest pain. The anxious client may have difficulty answering questions and focusing on the instructions being given and may expend excessive amounts of precious energy in the process. Therefore, recognition and control of anxiety bring both psychological and physiological benefits.
OUTCOME IDENTIFICATION AND PLANNING
In identifying goals and planning nursing care for the client with oxygenation disorders, carefully consider individual goals for each nursing diagnosis and each client; the goals should be individualized to reflect the client’s capabilities and limitations. In many cases, identifying desired outcomes of care is best accomplished in small steps, progressing from one level of functioning to the next until the ultimate objective is attained. Such an approach prevents the client from feeling overwhelmed with the magnitude of the task at hand while allowing for the satisfaction of reaching intermediate outcomes. Outcomes may be based on physiological parameters such as respiratory rate or arterial blood gas values, on activity tolerance and client comfort levels, or on identified learning needs.
The outcomes for a particular client should be based upon the assessment findings that led to the nursing diagnoses at hand. For example, if a respiratory rate of 30 breaths per minute with a shallow breathing pattern and suprasternal retraction led to a diagnosis of ineffective breathing pattern, then the desired outcome of intervention might be a respiratory rate of 20 breaths per minute or less and the absence of retractions. Achievement of the outcome indicates resolution of the problem.
IMPLEMENTATION
Interventions to Promote Airway Clearance
Interventions to promote airway clearance focus on clearing the airways of secretions, relieving bronchospasm, and, wheecessary, bypassing the natural airway structures with an artificial airway. All of these procedures are facilitated when the client has been well informed of the purpose for the interventions and knows what to expect.
Teach Effective Coughing
Effective coughing techniques may need to be taught to the client experiencing either short-term or chronic airway obstruction. Coughing is an important element of postoperative care in order to prevent pulmonary complications.
Effective coughing should be preceded by a series of slow, deep breaths. One technique that may be useful is “huffing,” or delivering a series of short, forceful exhalations, prior to actual coughing. The intent is to raise the sputum to the level where it can then be coughed out. If the client is recovering from thoracic or abdominal surgery, splinting the incision by holding a pillow firmly against it will reduce the pain caused by coughing. In most cases, assisting the client to a sitting position will increase the effectiveness of the cough.
Assess the sputum produced by coughing, noting the amount, color, and odor. Recognize that the client may become fatigued after coughing and need a rest period; also offer oral care such as a mouth rinse after sputum has been expectorated.
Initiate Postural Drainage and Chest Physiotherapy
Postural drainage and chest physiotherapy (CPT) are techniques intended to promote the drainage of secretions from the lungs. Positioning for drainage of each of the lung lobes is accompanied by percussion and/or vibration applied to the chest wall to loosen secretions (Figure 32-17). Percussion involves using a cupped hand to beat firmly on the chest wall (Figures 32-
Measures should be taken to minimize the client’s anxiety and discomfort during these procedures. Pain medications, if indicated, should be timed so that their effectiveness peaks at the time of the treatment. Also, the nurse must recognize that some clients may be unable to tolerate certain postural drainage positions, and the treatment must be modified. Those with congestive heart failure or increased intracranial pressure particularly will not be able to tolerate a head-down position.
Monitor Hydration
Hydration, that is, the provision of adequate fluid intake, is important in thinning the pulmonary secretions so that they may be more easily expectorated. This may be beneficial in cases of pneumonia, bronchitis, and asthma. Clients experiencing congestive heart failure, on the other hand, may require limitation of fluid intake to reduce pulmonary congestion due to fluid volume overload.
Each exhalation contains not only carbon dioxide and other gases but also water vapor. This “insensible fluid loss” will be increased in those who are tachypneic as well as in clients receiving supplemental oxygen if the oxygen is not adequately humidified. Artificial airways that bypass the natural humidification processes of the nose and oropharynx also contribute to increased insensible fluid losses. Drying and inflammation of the respiratory mucosa may result. For this reason, humidification of inspired oxygen, especially that which is delivered through an artificial airway, is very important.
Administer Medications
Medications that assist in airway clearance include expectorants, mucolytics, and bronchodilators. It may be beneficial to administer the medications before chest physiotherapy or postural drainage treatments in order to maximize the treatment’s effectiveness. Clients must be taught the name of the medications they are receiving, the purpose of the medication, the dose, and how it is to be taken. The most common and/or most significant side effects should also be reviewed with the client. A summary of medications for airway clearance is presented in Table 32-8.
Monitor Environmental and Lifestyle Conditions
Environmental and lifestyle conditions may greatly influence the client’s long-term recovery. Allergic conditions such as asthma may improve dramatically if the allergens to which the client is sensitive are identified and removed from the client’s environment. Certain allergens such as animal dander or feather pillows may be relatively easy to eliminate; others, such as house dust and pollen, may be impossible to eliminate but can be reduced using devices such as air filters.
Smoking is a significant contributing factor in both heart and lung disease. Smoking cessation may not reverse advanced disease but will often reduce the client’s symptoms and improve the quality of life. Smoking cessation programs and support groups, along with nicotine replacements such as transdermal patches, may help the client succeed in quitting smoking.
Introduce Artificial Airways
Artificial airways (Figure 32-19A–D) may be used for clients with significant airway obstruction that cannot be relieved by more conservative means or who require mechanical ventilatory support. Nasal airways, also known as nasal trumpets, may be placed in conscious adults who have adequate breathing ability but require assistance in keeping their upper airways open. These airways are usually fairly well tolerated and can provide a conduit for frequent nasotracheal suctioning while minimizing trauma to the nasal mucosa.
The oral airway is used to maintain the tongue away from the posterior oropharynx in the unconscious client. It is essential to choose the correct size, since an airway that is too large may actually cause occlusion, while one that is too small may compress the tongue, stimulating the vomiting center. Oral airways are not well tolerated in conscious individuals, who may gag and vomit if an oral airway is in place.
Endotracheal tubes bypass the upper airway structures altogether; they may be inserted via the nose or mouth and are passed beyond the vocal cords into the trachea. An inflatable cuff near the distal end of the tube serves to seal off the airway, allowing for mechanical ventilatory assistance and protecting the airway from aspiration.
Since endotracheal tubes bypass the filtration and humidificatioormally provided by the nose and oropharynx, care must be taken to humidify the inspired air and to prevent introduction of pathogenic organisms into the lungs. Meticulous attention to aseptic technique when caring for clients with endotracheal tube and ventilator circuits is mandatory.
Mouth care must be provided for the client with an endotracheal tube. The tube prevents adequate swallowing, so the client will be unable to eat. Frequent cleansing and suctioning of the oral cavity (every 2 hours) reduces discomfort and the risk of breakdown and infection of the oral mucosa.
Nutritional needs for the client with an endotracheal tube must be addressed by providing enteral feeding (via nasogastric or gastrostomy tube) or total parenteral nutrition (hyperalimentation). Whatever the means, adequate nutrition is necessary to maintain and improve respiratory muscle strength.
A tracheotomy is a surgical procedure done to provide long-term airway support or as an emergency procedure when an endotracheal tube cannot be passed successfully. An opening (stoma) is made in the trachea below the cricoid cartilage, and a semirigid plastic tube (tracheostomy tube) is passed through the opening and into the trachea. A cuff, similar to that in an endotracheal tube, is inflated near the distal airway.
Many tracheostomy tubes consist of two tubes or cannulae: an outer cannula that stays in place and an inner cannula that can be removed to be cleaned or replaced. This permits thorough removal of encrusted secretions to prevent occlusion of the airway. The outer cannula is connected to a flange that permits the tubes to be secured around the neck with twill tape or a cloth strap. See Procedure 32-1 for tracheostomy care.
Like an endotracheal tube, a tracheostomy tube bypasses the upper airways, so humidification and prevention of infection must be considered. Because both types of airways prevent the movement of air through the vocal cords, which produce speech, the client will not be able to talk while these tubes are in place (some long-term tracheostomy clients may be outfitted with a tracheostomy tube that has slits, or “fenestrations,” that permit speech).
If possible, reviewing an alternate method of communication prior to tube insertion can reduce the anxiety and isolation that may be felt by the intubated client. Writing of messages and use of an alphabet board are two possible methods of communication. Significant others should also be advised that the intubated client will not be able to speak but can hear and understand what is being said.
Suction the Airway
Suctioning of the airway, whether a natural or artificial airway, may be necessary to clear secretions the client cannot remove by coughing. Suctioning becomes especially important when an endotracheal tube or tracheostomy tube is present because coughing is significantly impaired by these devices.
Nasotracheal suctioning involves passing a suction catheter or nasal trumpet through the nare, down the pharynx, through the larynx, and into the trachea. See Procedures 32-2 and 32-3 regarding suctioning. Once the tip is in the trachea, a strong cough reflex will often be elicited. At this time suction is applied to the catheter and it is withdrawn while a twisting motion is applied to the catheter.
Endotracheal suctioning involves passing the suction catheter through the endotracheal tube or tracheostomy into the trachea and applying suction as the catheter is withdrawn.
Interventions to Improve Breathing Patterns
Properly Position Client
Client positioning to improve breathing patterns may begin by taking cues from the client. If the client finds that breathing is easier in an upright or sitting position, you should allow that position to be maintained.
Supporting the client with elevation of the head of the bed or with pillows can reduce the client’s workload and minimize fatigue. Maintaining proper body alignment and preventing slouching or slumping in the bed increase the efficiency of ventilatory efforts.
As previously stated, clients with obstructive respiratory disease may find that leaning forward, with the clavicles elevated, is most comfortable. Providing an overbed table for the client on which to rest his or her elbows may facilitate this position, provided the wheels are locked or removed to prevent the table from rolling away and placing the client at risk for a fall.
Teach Controlled Breathing Exercises
Controlled breathing exercises may also improve breathing efficiency for the client with obstructive respiratory disease. One technique that is especially useful is pursed-lip breathing. This technique involves forced exhalation against pursed (partially closed) lips, which maintains positive pressure in the lungs during the expiratory phase and prevents collapse of the smaller airways.
This in turn reduces the amount of air trapping characteristic of obstructive disease.
Deep-breathing exercises encourage the client to take slow, deep breaths instead of the rapid, shallow breathing pattern that may be present in restrictive lung disease and in those who are anxious. Abdominal breathing involves the use of the abdominal muscles to pull the diaphragm downward. Placing your hand on the client’s abdomen and instructing the client to watch it rise give a visual aid to teaching the technique.
Apical and basal expansion exercises direct the client to focus on achieving maximal expansion of the upper lung lobes (apices) and lower lobes (bases), respectively. To perform these techniques, place your hands flat against the chest wall just below the clavicles for apical exercises or over the lower ribs along the midaxillary lines for basal exercise and apply gentle pressure. Instruct the client to push your hands away with the chest wall by breathing.
These exercise should be repeated several times a day.
Incentive spirometry is another technique used to encourage deep breathing. The client draws air through the spirometry device, which measures the volume of air displaced by moving a float ball or similar device up a column. Goals (incentives) can be marked on the spirometer and the client can compare his or her progress, with the desired goal. Incentive spirometry is often performed in the care of postoperative clients and is usually done every 1 to 2 hours while awake.
Deep breathing may also be augmented using intermittent positive-pressure breathing (IPPB). An IPPB machine delivers a volume of air under pressure through a mouthpiece when the client draws air through the mouthpiece. IPPB requires the client’s cooperation, so preparatory teaching is essential. IPPB may include the administration of aerosolized medications and may be followed by coughing exercise, CPT, and postural drainage.
Introduce Chest Drainage Systems
Chest drainage systems (chest tubes) improve breathing patterns by removing accumulations of air and/or fluid from the pleural space, permitting the lungs to return to normal expansion. The tubes are inserted through the chest wall via a stab wound; multiple holes in the tip of the tube collect drainage from the pleural space. This drainage is then collected into a drainage system by either suction control or gravity. A special feature called a water seal prevents the reintroduction of air into the pleural space through the chest tube.
Interventions to Improve Oxygen Uptake and Delivery
Administer Oxygen
Oxygen uptake in the pulmonary capillary beds can be improved by increasing the concentration of oxygen in the alveolar air; this increase in the partial pressure of oxygen in the alveoli (PaO2) increases the driving pressure for gas diffusion across the alveolar-capillary membrane.
The percentage of oxygen in the inspired air is referred to as the fraction of inspired oxygen, or FiO2, expressed as a percentage; normal atmospheric air has an FiO2 of 21%. Supplemental oxygen delivery systems are capable of increasing the FiO2 to anywhere from 24% to nearly 100% oxygen (Figures 32-27 and 32-28). See Procedure 32-4.
Oxygen administration, like the administration of any drug, is not without hazards. Clients who have chronic pulmonary disease associated with carbon dioxide retention (hypercapnia) may become insensitive to carbon dioxide levels to drive their respiratory rate. Instead, these clients may depend upon a chronic low oxygen level in the blood (hypoxemia) to stimulate their respiratory drive. While low-flow oxygen may be beneficial to these clients, excessive oxygen administration may obliterate that hypoxic drive, resulting in apnea.
Another possible hazard of oxygen administration is oxygen toxicity. Prolonged administration of high FiO2 (greater than 50% for more than 24 hours) may actually damage lung tissue and produce severe respiratory difficulties.
The mechanisms by which oxygen toxicity occurs are twofold. First, it should be understood that 78% of the inspired air consists of the gas nitrogen. Although nitrogen is (under normal conditions) physiologically inert, it does serve an important function in the lung: it keeps the alveoli open simply by occupying space. High concentrations of oxygen displace nitrogen from the alveoli; as this oxygen is absorbed by the alveolar capillary blood, the volume of gas in the alveolar space is reduced and the alveoli collapse.
Once the alveoli have collapsed (atelectasis), no airflow occurs and the work of breathing increases dramatically.
Second, oxygen in high concentrations is toxic to the type II alveolar cells, which are responsible for the production of surfactant. Surfactant is a substance that assists in keeping the alveoli open by reducing the alveolar surface tension (the tendency of the alveolar walls to collapse upon themselves).
Atelectasis results when surfactant is insufficient. Widespread atelectasis due to oxygen toxicity may result in a syndrome known as the adult respiratory distress syndrome (ARDS), which is characterized by diffuse pulmonary edema, severe stiffness of the lung tissue, and profound hypoxemia.
Administer Blood Components
Blood component administration is indicated when the client’s oxygenation is impaired because of decreased circulating blood volume, decreased hemoglobin concentration in the blood (anemia), or hemorrhage. Red blood cells, plasma, clotting factors, proteins, or whole blood may be administered. Since a blood transfusion is really a type of tissue transplant, extreme care must be taken to decrease the possibility of an immune system rejection response known as a transfusion reaction.
Interventions to Increase Cardiac Output and Tissue Perfusion
The client with impaired cardiac output and tissue perfusion is likely to be experiencing edema of the lower extremities and/or the lungs, fatigue, activity intolerance related to poor tissue oxygenation, and possibly angina and/or intermittent claudication. Interventions are aimed at reducing symptom severity while optimizing cardiac performance.
Manage Fluid Balance
Management of fluid balance is a cornerstone in the care of the client with reduced cardiac output. If congestive heart failure is present, fluid intake may be restricted to prevent edema and circulatory overload.
Often, sodium intake is also limited because sodium promotes fluid retention. Diuretics may also be given to increase fluid excretion by the kidneys.
Monitoring of fluid balance by the nurse may involve the measurement of fluid intake and output (I&O) and measurement of daily weights. I&O measurement involves teaching the client the importance of accounting for all intake and output and providing a container for the measurement of urine. Daily weights should be performed at the same time each day (usually early in the morning) with the same amount of clothing on, and on the same scale, to maximize accuracy.
Clients receiving diuretics may also require monitoring for electrolyte imbalances. Potassium, particularly, may become depleted in the client receiving loop diuretics such as furosemide. Encouraging the consumption of potassium-rich foods such as bananas, and perhaps potassium supplementation, is often required.
Suggest Activity Restrictions and Assistance with Activities of Daily Living
Activity restrictions and assistance with activities of daily living (ADL) should be based upon the client’s activity tolerance. The purpose of activity assistance is to decrease the oxygen demands of the body. The client’s activity tolerance may be gradually increased through a sequence of exercise protocols as part of a cardiac rehabilitation program. Such a program incorporates careful monitoring of the client as the exercise level increases over time.
Position Client Properly
Positioning of the client with decreased cardiac output is done to decrease the fluid load to the heart and to decrease the development of pulmonary edema. The venous system is able to pool blood when aided by gravity; this “venous capacitance” is increased when the client’s head and upper body are elevated and the legs are in a dependent position. Although it is customary in the hospital environment to place clients in a supine position, this position may be detrimental for the client with congestive heart failure, as evidenced by worsening dyspnea, tachycardia and tachypnea, and decreased arterial oxygen saturation.
Administer Medications
Medications to improve cardiac output and perfusion include diuretics as mentioned above, cardiac glycosides, and other inotropic agents. Antihypertensives, nitrates, and vasodilators may also be given to increase cardiac oxygen supply and/or reduce the myocardium’s demand for oxygen. Table 32-9 lists the drugs most commonly used.
Emergency Interventions
Complete airway obstruction, cardiac arrest, and respiratory arrest are emergency situations that will result in death if not immediately rectified. Nurses receive regular training in the basic life support techniques described below; hands-on practice is an essential component of that training, and this text is not intended to serve as a substitute.
Remove Airway Obstruction
Complete airway obstruction is often the result of aspiration of food or some other foreign object into the trachea. The presence of a complete airway obstruction is characterized by an inability to speak or cough; the victim may also raise his or her hands to the throat and will likely appear very anxious. The rescuer should verify that obstruction is present by asking the victim, “Are you choking?” Relief of the obstruction is attempted by way of the Heimlich maneuver, which is described in Procedure 32-5.
Initiate Cardiopulmonary Resuscitation
Cardiac and respiratory arrest requires artificial support of circulation and ventilation if the victim is to survive.
Cardiopulmonary resuscitation (CPR) is the accepted technique of basic life support, as described in Procedure 32-6.
The technique described above is used for adult victims; different techniques are applied for children and infants and can be learned through courses such as those offered by the American Heart Association or the American Red Cross.
Interventions to Address Associated Nursing Diagnoses
Explore Lifestyle and Activity Adaptations
Lifestyle and activity adaptations may be necessary for the client with chronic alterations in oxygenation.
Interventions related to lifestyle and activity have three general purposes:
• To minimize energy and oxygen consumption
• To reduce factors that contribute to the disease process
• To systematically increase activity tolerance
Measures to reduce energy and oxygen consumption are chosen after a careful assessment of the client’s activity tolerance. Clients may need assistance with activities of daily living, including hygiene and toileting; however, it should be noted that complete bedrest is not always the best option. Many clients find that using a bedside commode or toilet is less physically taxing than using a bedpan, especially for bowel movements.
Occupational roles may also need to be modified. If the client is not able to continue working in the old job, it may be possible to take on a new job that is less taxing or to reduce the number of hours worked. If such changes are not possible, the client may have to quit working altogether.
All of these possibilities may cause much distress to the client and family, who must grapple with role issues, authority and autonomy issues, and possibly financial concerns.
Signs of inadequate family coping, such as marital discord, anger or hostility, sleep disturbances, and depression, should be noted and appropriate interventions, such as a referral for counseling, should be instituted.
Lifestyle adaptations aimed at reducing factors that contribute to the disease process include removal of allergens from the environment, smoking cessation, and control of modifiable risk factors for heart disease.
Allergen control and smoking cessation were discussed in the section Interventions to Promote Airway Clearance. Modification of cardiac risk factors includes smoking cessation as well as dietary alterations and weight control, control of diabetes and hypertension if present, exercise, and stress management. A comprehensive cardiac rehabilitation program addresses all of these issues while monitoring the client’s progress toward his or her individualized goals.
Encourage Dietary and Nutritional Modifications
Dietary modifications for cardiovascular disease may include reduction of sodium intake and reduction of total fat, saturated fat, and cholesterol intake. Sodium consumption may be reduced by decreasing or eliminating salt used in cooking and added at the table and avoiding highly processed foods such as prepared meats, canned meat or fish, and many prepared sauces.
The client should be taught to examine food labels for sodium content per serving.
The client who is not receiving adequate nutrient intake because of poor appetite or severe dyspnea will need assistance in finding ways to increase intake of calories and essential nutrients. Eating small, frequent meals of high nutritional value and using dietary supplements are often helpful.
Promote Comfort
Promoting comfort for the client with oxygenation disturbances can be a challenge but is extremely important. Comfort influences the client’s ability to eat, sleep, learn, and cope with the illness and the care being provided. Altered comfort related to pain is best approached by removing or modifying the cause of the pain if possible and administering analgesics if indicated. The use of analgesics in the postoperative client is particularly important in allowing the client to participate fully in deep-breathing and coughing exercises.
Pain related to tissue ischemia is best relieved by improving the oxygen delivery to the tissues while reducing the oxygen demand. The first response to ischemic pain should be to rest the affected tissue. If the pain is in the legs, for example, the client should sit down. Improving delivery of oxygen to the legs in the client with peripheral vascular disease may involve positioning the legs lower than heart level (elevating the legs will often make the pain worse).
Heart pain related to ischemia (angina pectoris) should also be dealt with first and foremost by resting. Resting will decrease the heart’s workload and in some cases is sufficient to relieve the pain. Improving oxygen delivery to the heart may be accomplished by providing supplemental oxygen or by using medications, such as nitrates, that improve coronary blood flow. In some cases, narcotic analgesics such as morphine are necessary.
Complementary Therapies
Many complementary therapies that enhance oxygenation originate in ancient healing traditions of
Dean Ornish, M.D., has successfully reversed coronary artery disease by using yoga with dietary changes, moderate exercise, and support groups.
Herbs
Herbs are often used with relaxation techniques, exercise, and diet to prevent diseases of the cardiovascular and respiratory systems; see the accompanying display for commonly used herbs for these systems. Respiratory stimulants are expectorants that loosen mucus from the respiratory system. Lobelia (Indian tobacco) contains lobeine, a nonaddicting substance similar to nicotine, and is often used to quit smoking.
EVALUATION
Clients with compromised oxygenation status need careful nursing care to address both their physical and psychological needs. Evaluation will be based on the outcomes and goals that the nurse and client have established together. In many instances, the evaluation of the success of the specific interventions will be a mattter of degree, that is, the degree to which the client is or can be returned to a satisfactory state of respiratory functioning.
It is important when evaluating progress to revisit the initial plan of care to determine if each expected outcome was within reasonable expectations and then to revise the goals, interventions, and plan of care to reflect truly reasonable expectations.
KEY CONCEPTS
• Adequate tissue oxygenation is essential to survival and may be threatened by deficits in air movement through the lungs to deliver fresh air to the alveoli (ventilation), the exchange of oxygen and carbon dioxide across the alveolar-capillary membrane (diffusion or external respiration), oxygen transport in the blood, the delivery of oxygen to the tissues (circulation), or the uptake of oxygen by the cells (internal respiration).
• Impairment of oxygen delivery to the tissues results first in compensatory efforts such as anaerobic metabolism and increased oxygen extraction; when these efforts fail, tissue ischemia and infarction will ensue.
• Client teaching related to oxygenation impairment involves teaching about the disease process, treatments, and lifestyle alterations that may be indicated; teaching should involve not only the client but also the family.
• Nursing care related to oxygenation focuses on maintaining a patent airway, promoting effective ventilation, promoting optimal circulation and perfusion, and meeting the client’s learning, nutritional, activity, and sleep needs.
• A holistic approach to care recognizes that each of the problems experienced by the client with oxygenation deficits is interrelated.
• Emergency support of airway, ventilation, and circulation is achieved by instituting the Heimlich maneuver for airway obstruction and cardiopulmonary resuscitation for cardiopulmonary arrest.
