Effects on Cardiovascular Function

The cardiovascular system, including the heart, the arteries, the venous channels, and the lymph vessels, is designed to deliver blood to and from the capillaries where the exchange of the vital respiratory gases and other metabolic substances occurs. Three major changes in cardiovascular system function have been identified as resulting from immobilitv: orthostatic hypotension, increased work load of the-heart, and thrombus formation.

ORTHOSTATIC HYPOTENSION

Perhaps the most dramatic of these changes is the deterioration of the ability of the autonomic system to equalize the blood supply when a person who has been recumbent for a long period attempts to stand up. AII nurses are aware that when patients first get up after several days in bed, they may suffer from weakness, dizziness, or giddiness. They may even faint.

Taylor found that when healthy young men were put to bed for 21 days, the ability of the cardiovascular system to respond to the upright posture was not regained for more than five weeks after activity was resumed (1). This was due to two factors: loss of general muscle tone and decrease of efficiency of the orthostatic neurovascular reflexes. The loss of muscle tone resulting from complete disuse is estimated to be 10-15 percent of strength per week. One potent factor assisting venous return is the so-called "venopressor mechanism" in which the contraction of muscles causes pressure on veins. The venous valves which prevent the backflow of blood close, hence muscle action assists venous return of blood to the heart. In the absence of this type of assistance, the venous blood tends to pool in the lower parts of the body.

The second factor, decreased efficiency of the orthostatic neurovascular reflex control of the vessels themselves, is a puzzling complication. At the very time that there is an inability to maintain blood pressure when erect, patients show signs of strong activity of the sympathetic nervous system such as palmar sweating, pallor, and restlessness which proves that the nerves are intact and central function is normal. Birkhead, who also demonstrated that persons show decreased tolerance to the erect posture after 42 days at bed rest, found a normal autonomic response to exercise in the supine position which confirmed positively that the problem is a peripheral rather than a central nervous system onset (2). Browse reported that this local failure of the nervous system may result simply from its

habituation to the lower pressure. higher flow, and increased diameter of vessels in the supine position (3). In such a situation the nervous stimuli and the increased intramural pressure suddenly thrust upon them.

INCREASED WORK LOAD

The second change in cardiovascular system function resulting from immobility is that the heart itself works harder in the resting supine position than in the-resting erect position. The physiologic effect-on the heart of bed rest as a method of treatment for myocardial infarction has received much attention in recent literature. Coe demonstrated that the heart works 30 percent harder when a person is in the recumbent position than when he is in a sitting position (4). Several physiologic factors are involved in this phenomenon.

Changes in the vascular resistance and the hydrostatic pressure associated with lying down alter the distribution of blood within the body. With the release of gravity pressure, part of the total blood volume leaves the legs to be redistributed in other parts of the body, thus increasing the volume of the circulating blood which must be handled by the heart. The cardiac output and the stroke volume increase with lying down. Studies by Chapmen found a 24 percent increase in the cardiac output and a 41 percent increase in the stroke volume when healthy men were put on enforced bed rest (5). Also the heart rate itself increases progressively as the patient remains bedfast. Taylor found that, even in healthy young men who were confined to bed, the cardiac rate at rest increased approximately 0.5 beat per minute per day (l). After three weeks of bed rest, these men showed an increased heart rate of 40 beats per minute during moderate work. They required 5 to 10 weeks of reconditioning before their heart rates during work matched those prior to the prolonged bed rest. This progressive increase of the testing heart rate and greater tachycardia during work indicate progressive decrease of ability in cardiovascular function. During tachycardia the recovery time for the heart muscle is decreased and the heart muscle fatigues more quickly. Tavlor demonstrated that the abilitV of healthy young men to walk 3.5 miles an hour on a 10 percent incline was decreased by -5 percent after only three weeks in bed due to decreased cardiac reserve (1).

Another factor affecting the work load of the heart during bed rest is concerned with the Valsalva maneuver. When a person uses his arms and upper trunk muscles to expedite moving about in bed, he fixes his thorax and usually holds his breath. In so doing the breath is pressed forcibly against the closed glottis- the Valsalva maneuver. This same basic action occurs with straining at the stool. During this period of thoracic fixation

without expiration. the intrathoracic pressure is elevated and interferes with entry of venous blood into the large veins. With release of the breath, there is a consequent fall in intrathoracic pressure, and a large surge of blood is delivered to the heart at one time. This can result in tachycardia which, in turn, can result in cardiac arrest if the heart is not functioning optimally. Estimates on the frequency with which this maneuver is used by bedfast patients range from 10 to 20 times per hour.

THROMBUS FORMATION

The third major hazard to cardiovascular function resulting from immobility is thrombus formation. It is believed that immobilitv predisposes to thrombus by contributing to venous stasis, hypercoagulability of the blood, and external pressure against the veins. Venous-stasis-in-the legs results from the lack of muscular contraction which ordinarily promotes venous return. Evidence that bed rest actually contributes to hypercoagulability of the blood is difficult to document, but several theories have been presented. Some physiologists believe that bed rest results in an increased concentration of the formed eIements in the blood which by increasing viscosity would predispose to clotting. Dehydration which often accompanies immobility also is considered a factor leading to hypercoagulability of the blood. One familiar hypothesis of blood coagulation states that prothrombin is activated by material from the platelets and calcium to form thrombin, which, in turn, becomes the activating enzyme for the conversion of fibrinogen to fibrin. It is believed that the vital role of calcium in this process of coagulation supports the theory that the increased blood level of calcium resulting from immobility may result in hypercoagulability of the blood.

Another factor predisposing to thrombus formation. External pressure on the blood vessels, is well known to nurses. The danger of restricting circulation by allowing pressure from the bent knee gatch or pillows under the knees is often voiced. However,-the lateral recumbent positiion so often used in positioning patients may also result in both circulatory stasis and damage to the intima of the blood vessels. The upper leg will rest heavily on the lower leg unless care is taken to prevent it. When the intima is damaged a layer of platelets is laid down over the damaged area, and this plaque may be the basis for a clot.

While studies related to predisposition to thrombus formation because of immobility are contradictory, a report by Sevitt and Gallagher showed that on autopsy the number of thrombi found was in direct proportion to the length of time patients were at bed rest (6). Their findings support the

contention that venous stasis and the other effects of immobility play a. major etiological role in venous thrombus formation.

NURSING IMPLICATIONS

These effects of immobility on the cardiovascular system dictate that no patient should be allowed to remain immobile any longer than absolutely necessary, Even when bed rest must be imposed, nursing measures, implied from the physiologic changes discussed, can prevent the hazards of immobility.

Exercises to prevent loss of muscle tone and to promote muscular pressure on-veins-to assist the return flow of blood to the heart should be included in any nursing care plan for the immobilized patient. These might include passive and active range of joint motion, isometric exercises, and self-care to the maximum permitted.

Seeing that the patient's position is changed frequently will alter the intravascular pressure and provide stimulus to the neural reflexes of the vessels and help prevent hypotension. Probably the most effective measure is changing the patient's position from horizontal to vertical. This can be achieved by elevating the head of the bed, or, when permissible, sitting the patient in a chair.

Patients need to be taught how to move and change position in bed without building up intrathoracic pressure. An overbed frame and trapeze can be provided if necessary and the patient taught to use it properly. To prevent the dangers inherent in repeated Valsalva maneuvers, he should be told to exhale rather than hold his breath while moving in bed.

The normal person changes position every few minutes, so that to plan position changes only every two hours is to condemn the person to discomfort or to the use of his own means of shifting weight or position.

Preventing constipation and positioning the patient for defecation in a well supported sitting or squatting position also will reduce the work load on the heart. And, finally, as activity is permitted, it must be gradual to avoid fatigue.

Effects on Metabolic Equilibrium

The effects of immobility on the metabolic processes cannot be discussed without some reference to closely related endocrine functions or some explanation of how interference with metabolic homeostasis profoundly influences the efficiency of all physiologic processes and other homeostatic mechanisms.

Functional changes resulting from immobility include reduced metabolic rate, tissue atrophy and protein catabolism, bone demineralization, alterations in the exchange of nutrients and other substances between the extracellular and intracellular fluids, fluid and electrolyte imbalance, and gastrointestinal by hyper or hypomobility.

When a person is consigned to bed, rest and inactivity, his metabolic rate falls in response to the decreased; energy requirements of the cells an the disequilibrium. of metabolic processes. Anabolic processes are retarded and catabolic activities are accelerated. Many of these have already been discussed in relation to the dysfunction of various other body systems: the process of protein breakdown leading to protein deficiency and negative nitrogen balance; the formation of decubitus ulcers; the excretion of electrolytes when catabolic processes are accelerated; the demineralization of bone as a consequence of reduced muscle tension and absence of weight-bearing stress on the skeleton; and the formation of urinary tract stones. And there are still other factors associated with bed rest that affect metabolism and fluid and electrolyte balance and have important implications for nursing. One of these is body temperature.

Bedclothing prevents the loss of heat by conduction and radiation. The supine position dilates blood vessels and, in order to throw off accumulating heat, the patient will sweat wherever skin surfaces touch In the creases in the neck, under breasts, the abdominal folds, the surfaces where the am-is rest against the chest, and in the axillary and perineal regions, sweating increases. All of this fluid loss carries with it essential electrolytes-sodium, potassium and chloride.)

It is known that the supine position reduces the production of adrenal cortical hormones, although the exact mechanism whereby this occur is not known. There are two groups of adrenal-cortical hormones that influence metabolism. One is the glucocorticoids which affect the metabolism of carbohydrate, protein, and fat; the other is the mineralocorticoids which are concerned with electrolyte balance (especially of sodium, potassium, and chloride).

Authorities currently are examining the influence of immobilization on other hormones produced in the body, but definitive information is not available

at this time. Recently, a second hormone (thyrocalcitonin) has been isolated from the thyroid. gland. Its function seems to be an adaptive one wherein it attempts to lower an elevated serum calcium.

Increased urinary excretion sometimes occurs when the patient is placed at bed rest especially during the first few days of immobilization. This is due to the fact that the circulation to the kidneys is increased in the recumbent position.

Stress reactions, both psychologic and physiologic, are commonly associated with immobilization and illness. The effect of stress on fluid electrolyte balance and on Other physiologic functions and psychologic behavior, should be kept in mind.

Diurnal patterns are the variation which occur in the physiologic operation of the body during the period of day and night. While an individual is awake. His metabolic rate, bud temperature, hormonal levels, and renal functions are active. During sleep the demands on these homeostatic mechanisms are reduced to a minimum. 'Whether the individual is asleep or not, the supine position in itself will result in the same minimal functional output. It is important for the nurse to consider these factors as they may affect the patient who is not allowed to sleep for any length of time, as in intensive care units; the individual who sleeps most of the time; and the patient who is awake all night and sleeps during the day. Each of these patient will have altered nutritional and fluid requirements.

The nursing measures which can help prevent some of the foregoing problems are not complex. The patient should remain up until the need for bed rest is strongly apparent. Allowing the patient to be " up and about," while dressed in daytime clothing, would produce a more natural metabolic state. If the patient is unable to ambulate, sitting in the chair would tend to prevent fluid and electrolyte loss from perspiration and prevent the basal metabolic rate and hormonal level changes that occur in the supine position.

For the patient who must be on bed rest, elevation of the head and upper torso on a schedule similar to turning schedules would alleviate many of the problems previously discussed. Minimal but sufficient bedclothing which is not tight enhances loss of heat by conduction and radiation, thus reducing the patient's fluid and electrolyte loss.

Increased fluid intake and high protein nutrition are essential to the patient regardless of the stage of his mobility if healing is to be hastened a electrolyte balance maintained.

The prevention of atrophy and of elevated serum calcium levels can be partially attained by range of motion, passive or active exercises, and weight bearing within the limits of the individual patient's capability.

Since metabolic homeostasis provides the framework for the composite of human function, any person when immobilized is confronted with aspects of the stress cycle. Reducing the effects of this process is contingent upon the nurse's ability to perceive, to interpret, and to intervene in the physiologic and psychologic pressure mechanisms

Effects on Motor Function

Motion is a fundamental property of most animal life. It is necessary for the maintenance of the structural stability and the metabolism of the musculoskeletal system, and requires both basic tonicity and intermittent work loads of the skeletal muscles. The daily mechanical stresses of normal activity promote strength, endurance, and coordination of the muscles; permit a balance of activities within bone to maintain its solidity and its capability to support the weight of the body; and contribute to cell nutrition by maintaining the muscle pump activity upon the blood circulation.

Motor function is a highly complex process of interaction of man and his environment, of integration of learned and reflex patterns, and of coordination of muscles, bones, skin, and the senses through the nervous system. Musculoskeletal deterioration from immobility is manifested in three major complications: osteoporosis, contractures. and decubitus ulcers.

OSTEOPOROSIS

Osteoporosis affects-the osseous structure of the body. Bone is a living structure, The vital matrix is fundamental to its growth and development and carries the calcium which gives the bone its solidity. Throughout life, the matrix and its calcium are continuously being built up and broken down by opposing cell forces in a dynamic state of equilibrium. Osteoblastic cells form the osseous matrix, while osteoclastic cells are continuously destroying the matrix through their opposing function of absorbing and removing osseous tissue from the bone. Since osteoblasts depend upon stresses and strains of mobility and weight bearing for proper functioning,

normal motor activity is necessary to their function of building up the bone matrix. If there is no activity, as with complete immobility, there is an absence of these daily stresses and strains.

As a consequence, the process of building up the bone stops, but the osteoclasts continue their destroying function, disrupting the state of equilibrium and causing structural changes until the supply of bone calcium becomes severely depleted. At the same time there is increased excretion of bone phosphorous and nitrogen, and the bone becomes demineralized. This change in bone composition results in the condition known as osteoporosis, or porous bone. As the decalcification process continues, the bones become spongy or porous and may gradually compress and deform. Because of the lack of structural firmness, the bone may be easily fractured.

A healthy, active person is not aware of the weight of his body straining against his bones for there is no sensation from these stresses. However, the person with osteoporosis may experience very intense pain when the bones must bear weight. Advanced osteoporosis causes more pain than many other chronic diseases, and yet it is often unrecognized and undiagnosed because at least 30 percent of the calcium must be lost from the bone before decalcification is revealed on an x-ray film.

Nurses must be aware that decalcification takes place during immobility regardless of the quantity of calcium intake. Increasing calcium in the diet is not recommended for it will not be used by the bone of the osteoporotic patient or the immobile patient. Unneeded calcium will only be added to the very large amount of calcium being excreted, often precipitating from the urine as renal calculi. Or it may be deposited in the muscles resulting in imyositis ossificans, or in the joints causing osteoarthropathy.

Osteoporosis can be largely prevented or decreased by the maintenance of weight bearing and muscle movement and the avoidance of complete immobility. The "normal" stress on the bones can be promoted through placing the patient in a weight-bearing position on a tilt table or an oscillating bed, or by having him stand or walk between parallel bars if he is able. A daily program of muscle activities against resistance should be planned. Not to be underestimated the value of encouraging the patient to participate in his care to his maximum ability, and thus contribute to his mobility.

CONTRACTURES

Contractures involving the muscles and other soft tissues surrounding a joint are the second major complication from decreased mobility. Muscle makes up 40 percent of the body. It is very important to the individual because it provides the power for movement and interaction with his environment. All tissues subjected to prolonged immobility undergo atrophy and functional incompetence from disuse. Atrophy, or the wasting away of muscle tissue, leads not only to a decrease in the muscle size but also to a decrease in functional movement, strength, endurance, and coordination.

Contractures occur when muscles do not have the activity necessary to maintain the integrity of their function that is, the full range of shortening and lengthening of their fibers. Contractures may occur with muscle imbalance in which one muscle is weak and its antagonist is stronger, or spastic, or both. Mild muscle spasm is one of nature's means of preventing further disability from osteoporosis and of splinting a part to prevent pain. Edema may mechanically splint a part and prevent muscle activity. Probablv the main cause of contracture of which the nurse must be ever cognizant is that of prolonged immobilization of a joint in one position. This may occur as a therapeutic measure or when emphasis has been on the establishment and maintenance of proper body alignment rather than on mobility and maintenance of function.

Whatever the predisposing cause of the contracture the fibers of the involved muscle shorten and atrophy resulting in a limited range of motion of the joint. Such a process may initially produce a reversible contracture that can be overcome by exercise and stretching, but eventually it will involve tendons, ligaments, and joint capsule and become irreversible, requiring surgical intervention or prolonged mechanical stretching for it release.

Because the prevention of contractures is much easier then the treatment, nursing measures are of great value. The first objective is to maintain body joints in their most fuctional anatomical position. Special care must be taken to prevent hip and knee-flexion contractures which may result from prolonged, faulty positioning with improper placement of pillows, or from gatched beds that keep the hips and knees continuously flexed. A bed board and a firm mattress are helpful in maintaining correct body positioning. A footboard can be beneficial in preventing foot drop, but only if it is used properly. It should be placed firmly against the bottom of the patient's feet to hold them at a right angle with the legs. It should not be placed at a distance where stretching to reach it will inadvertently create

the plantar flexion position of foot drop. In such a position the board is only useful for keeping the bed clothes from resting on the toes.

Nursing activities should include frequent and scheduled change of patient positioning and range of motion of all joints. These should be combined with the use of appropriate devices for temporary maintenance of the functional position of such parts as the wrist, hand, and fingers. Whenever possible, the patient should assume some of the responsibility for checking his position and for performing range of motion exercises. Health teaching which encourages the participation of the patient and his family can be vital in the prevention of contractures.

The skin may also be seriously affected by immobility. A normal, active individual with unimpaired sensory and motor function will change his position every few moments during waking hours and quite frequently during sleep. The patient who is paralyzed or debilitated may be unable to move himself. The patient who is without sensation to a part will not automaticallv move, for the stimuli of discomfort that usually lead to automatic shifting of position are not felt.

DECUBITUS ULCERS

Decubitus ulcers occur under many different circumstances. Since proper circulation of the arterial and venous blood flow is partially dependent upon normal muscle action, muscle disuse during immobility often decreases the circulatory exchange in the soft tissues. Prolonged pressure on an area causes disturbances in the nerve impulses to and from this area, and also decreases the blood supply which in turn diminishes the nutrition of that part. In addition, constant pressure, particularly over bony prominences such as the sacrum, trochanters, ischial tuberosities, and heels, compresses and obstructs the blood flow causing ischemia or local anemia of a tissue. Ultimately, ischemia leads to necrosis and ulceration. The ulcerative areas can become so massive that it may take many months or years of treatment and costs thousands of dollars to repair them during which time the patient's mobilitv will be further limited. Although decubitus ulcers may occur in healthy persons pressure against a part with resultant ischemia and progressive tissue deterioration they are more likely to appear in malnourished persons who are in a negative nitrogen balance. Once the patient regains nitrogen balance, and there is more nitrogen intake than output, there usually be improvement in regeneration and growth of the tissues.

When a patient has a decubitus ulcer the prevention of infection is a prime nursing concern. Infection not only retards healing of the ulcer, but also

may lead to systemic infection. This in turn may cause osteomyelitis for example, or even death.

Osteomyelitis seriously effects motor function. The infection destroys the blood supply to the bone. The bone deprived of nutrition acts as a foreign object, and a haven for organisms. In order to promote healing, the necrotic bone is surgically removed and the part is immobilized until the bone regenerates.

Nursing precautions to prevent such occurrences are paramount. The development of a decubitus ulcer in any person who has sensation is completely unwarranted with the present knowledge that is available. Even in persons who have experienced a loss of sensation, the development of it bedsore is to be considered an unnecessary complication. The immobilized patient should be turned frequently. Definite patterns of helping the patient to shift body weight off the bonv prominences are necessary or pressure areas will develop and tissue will break down. Such aids as turning frames, oscillating beds, or air-filled or water-filled alternating pressure mattresses are useful but do not obviate the need for constant care to vulnerable areas.

During each position change, the skin should be inspected for areas of tenderness edema, coldness, or redness. Meticulous skin care should be given and a dry and, wrinkle-free bed provided. A regular toilet schedule on a 24-hour basis, time-tailored for ach individual patient, will reduce the incontinence that contributes to skin breakdown. Two long-standing techniques of routine hospital care should be abolished. One is the use of rubber rings and doughnuts which do not prevent decubitus u1cers, but actually compress it larger area around the pressure point, decrease circulation to it, and contribute to the formation and enlargement of the ulcer. The other is the use of alcohol for skin massage since this dries the oils of the skin and. creates cracks and subsequent broken down areas.

If a pressure area should develop, prompt measure should be taken to promote healing to close this portal of entry for infection, and to reduce the loss of serum proteins. The diet should provide enough protein to compensate for these losses should they occur, and enough carbohydrates and fats so that maximum utilization of the proteins is possible.

NURSING GOALS

In summary, prevention is the common thread weaving through nursing care plans for coping with musculoskeletal deterioration in the immobilized

patient. The main objectives of such nursing care should be: to avoid complete immobility through it planned program. of exercises and activities geared to the capability of the patient; to give close visual observation to the body positioning and alignment, as well as to skin condition; to see that the patient has it well-balanced diet, supplemented as necessary to meet special needs; and to instruct the patient and family so they can assist in such prevention.

Effects on Respiratory Function

Full utilization of his available pulmonary energy for the activities important to him is the patient's right -his right to breathe. Respiration as a physiologic process is the gaseous exchange between an organism and its environment. Oxygen is absorbed and carbon dioxide is eliminated. The purpose of the respiratory movements is to renew the air in the alveoli, to ventilate, to move air in and out. The lungs lie within the thorax and communicate with the environment via the bronchioles, bronchi and trachea. As the thoracic cavity changes in size through the contraction and relaxation of the muscles of respiration (abdominals, external and internal intercostals, and the diaphragm), the lungs also change in size because of shifts from negative to positive air pressure. The lungs expand on inspiration (compliance) and relax on expiration (elastic recoil). These movements are normally so rhythmic and easy that the individual is not aware of his breathing.

Gaseous exchange can only occur when the air is in the alveoli, in close contact with the circulating blood, and when the air is constantly being changed, providing a fresh supply of oxygen and removing the carbon dioxide as it accumulates. Physiologists have found that in order for the exchange of gases to occur there must be a large, thin, moist permeable membrane and a difference in the concentrations of molecules of the gas on either side of that membrane. There is a tendency for such a difference in concentration to be equalized through the movement of molecules from a higher concentration to the lower concentration. The alveoli and capillaries provide the large, thin. moist membrane. The differences in the pressure of the gas in the capillaries and in the alveoli provide the differences in molecular concentrations. The pressure of oxygen in the alveoli is higher than the pressure of oxygen in the capillaries. The reverse is true of carbon dioxide. Thus, oxygen is absorbed into the blood carbon dioxide is eliminated.

Changes in the normal physiologic functions of the respiratory system during, short periods of immobility may at first be compensatory or strives to pre adaptive as the body serve homeostasis. During immobility the basal metabolism is decreased, and the cells require less oxygen for use in the synthesis of proteins. As a consequence, less carbon dioxide as it byproduct of cell metabolism is produced. Respirations become slower and less deep in order to compensate for the lessened demand and maintain the needed and constant concentrations of these two elements, oxygen and carbon dioxide, in the blood and extracellular fluids.

Three physiologic effects on the respiratory system may occur as a result of immobility-decrease respiratory movement of secretions, and disturbed oxygen carbon dioxide balance.

1. DECREASED RESPIRATORY MOVEMENT

Respiratory movement may be limited by the counter resistance of the bed or chair to chest expansion when the patient is allowed to sit to long or lie too long on his back or side, or in a prone position. Chest cage expansion may also be limited by sitting or lying postures, which compress the thorax, by abdominal distention (secondary to an accumulation of feces, gas or fluid), and by the use of tight abdominal or chest binders. Anything that creates intra-abdominal pressure will prevent the normal descent of the diaphragm and limit inspiration. Movement of the chest may also be hindered by a diminution of muscle power and coordination. as a result of muscle disuse or decreased innervation. Further, the administration of anesthetics, narcotics, sedatives, and other pharmologic agents acting on the central nervous system may limit the rate and depth of the respiratory movement by depressing the respiratory center in the medulla, the sensory and motor areas of the cerebral cortex, and the cells of the spinal cord. These limitations to chest cage expansion necessarily result in a limitation of lung expansion and, eventually, in a substantial decrease in the compliance and elastic recoil of lung tissue. Thus, decreased lung expansion hinders the normally efficient and effective ventilation or the movement of air in and out of the lung time.

2. STASIS OF SECRETIONS

The normal movement of secretions out of the tracheobronchial tree is decreased whenever one of the normal cleansing mechanisms, such as coughing and changes in posture or position, is made ineffective. Prolonged immobility causes stasis and pooling of

secretions. The maintenance of a patent airway may be threatened or disrupted as the secretions collect. Poor fluid intake, dehydration, or anticholinergic drugs may render secretions thick and tenacious, and further interfere with their movement.

With the stasis of secretion, it is no surprise that the immobilized patient frequently contracts a tracheitis, bronchitis, or that old enemy, hypostatic pneumonia. Moreover, the collection of unmoving secretions provides an ideal medium for bacterial growth within the body, especially for pneumococcic, pseudominal, staphylococcic, and streptococcic organism.

Anesthetics, narcotics, and sedatives may also contribute to respiratorv complications by decreasing the rate and depth of lung expansion and ventilation, by depressing the cough center, and by slowing the reflex action of the epiglottis and thus permitting aspiration of secretions from the nasopharynx. The bulk of the unmoving secretions or the inflammatory edema may eventually obstruct the airway. The combination of the necessity to overcome resistance to chest and lung expansion, diminished muscular power, and an obstructed airways will require more subjective efforts for the act of breathing. Increased oxygen will be used and more carbon dioxide will be produced, in turn demanding that the immobilized patient try even harder to breathe at a greater rate and depth in order to counteract this deficient ventilation.

3. OXYGEN-CARBON DIOXIDE IMBALANCE

A decrease in respiratory movement and a decrease in the movement of secretions, therefore, result primarily in deficient ventilation and, in turn, limited diffusion of oxygen and carbon dioxide via the alveolar and capillary membranes. The exchange of oxygen and carbon dioxide may be further diminished by functional disabilities on the capillary "side" (as compared with changes on the lung "side" of membrane) because of the cardiovascular changes during immobility. The disturbance in the exchange will alter the normal oxygen-carbon dioxide balance in a cumulative manner, -with a continuing build-up of carbon dioxide in the blood because it cannot be adequately expired and a developing hypoxernia, creating tissue hypoxia, because adequate oxygen cannot be inspired.

At first, the increased concentration of carbon dioxide in arterial and venous blood acts as a respiratory stimulus, but continued strong

stimulation of the respiratory centers in the medulla and pons will eventually depress them and carbon dioxide narcosis will occur. A lowered oxygen concentration in the blood may provide respiratory stimulation via the aortic and carotid bodies for an interval, but, again, continued stimulation will lead to depression and this mechanism will also become ineffective.

Increasing arterial and venous concentrations of carbon dioxide, as carbonic acid and hydrogen ions, will create a respiratory acidosis. Without intervention, respiratory acidosis or narcosis will lead to respiratory failure or cardiac failure and death. Thus, a fourth possible physiologic effect of immobility on the respiratorv svstem is death!

NURSING IMPLICATIONS

Preventing respiratory physiologic changes from becoming functional disabilities is of primary importance in the prevention of the patient's right to breathe. Many of the activities the nurse performs daily pertain to respiration. One of the most important of these is the observation of respiratory function. While observing a patient's respiratory rate, she should also note the quality of the respiration. Are they deep or shallow? Wet or dry? Easy or labored? Is the patient using his neck muscles or abdominal muscles in breathing? Does he present any neurologic signs, such as restlessness or forgetfulness, which often are early indications of a deficiency of oxygen supply to the tissues? Does he have the late signs of hypoxia, cyanosis, and dyspnea? An anxious patient, perhaps using his neck muscles to facilitate breathing that is shallow, wet, or labored, needs the nurse's immediate care and means that the nurse was late in recognizing his need to breathe efficiently.

Another nursing activity is to help the patient routinely turn, cough, and breathe deeply. Patients as well as nurses must understand how beneficial it is to chest and lung expansion for the patient to turn off his back or side, stretch, out, and sit up straight at regular and frequent intervals. Also, how coughing secretions up and out facilitates adequate oxygen-carbon dioxide exchange. If the patient is unable to cough effectively, it may be necessary to suggest and use chest tapping to help loosen secretions, and postural drainage to remove them from the tracheobronchial tree.

The nurse must be able to teach a patient how to breathe deeply using his abdominal muscles, diaphragm- and intercostals in facilitating deep inhalation and prolonged expiration, and to encourage him to do breathing exercises regularly.

The use of these common nursing measures and the promotion of physical mobility through self-care activities will contribute to the prevention of the functional respiratory disabilities which may result from the physiologic effects of immobility. They will help preserve the patient's ability to breathe and to use his available cardiopulmonary energy for the activities, which are important to him.

THE EFFECTS OF IMMOBILITY

a. Cardiovascular System.

Venous stasis caused by prolonged inactivity that restricts or slows venous circulation. Muscular activity, especially in the legs, helps move blood toward the central circulatory system.

Increased cardiac workload due to increased viscosity from dehydration and decreased venous return. The heart works more when the body is resting, probably because there is less resistance offered by the blood vessels and because there is a change in the distribution of blood in the immobile person. The result is that the heart rate, cardiac output, and stroke volume increase.

Thrombus and embolus formation caused by slow flowing blood, which may begin clotting within hours, and an increased rate in the coagulation of blood. During periods of immobility, calcium leaves bones and enters the blood, where it has an influence on blood coagulation.

Orthostatic hypotension probably due to a decrease in the neurovascular reflexes, which normally causes vasoconstriction, and to a loss of muscle tone. The result is that blood pools and does not squeeze from veins in the lower part of the body to the central circulatory system. The immobile person is more susceptible to developing orthostatic hypotension. The person tends to feel weak and faint when the condition occurs.

b. Respiratory System.

Hypostatic pneumonia. The depth and rate of respirations and the movement of secretions in the respiratory tract is decreased when a person is immobile. The pooling secretions and congestion predispose to respiratory tract infections. Signs and symptoms include:

Increased temperature. Thick copious secretions. Cough. Increased pulse. Confusion, irritability, or disorientation. Sharp chest pain. Dyspnea.

Atelectasis. When areas of lung tissue are not used over a period of time, incomplete expansion or collapse of lung tissue may occur.

Impaired coughing. Impairment of coughing mechanism may be due to the patient's position in bed decreasing chest cage expansion.

c. Musculoskeletal System.

Muscle atrophy. Disuse leads to decreased muscle size, tone, and strength.

Contracture. Decreased joint movement leads to permanent shortening of muscle tissue, resistant to stretching. The strong flexor muscles pull tight, causing a contraction of the extremity or a permanent position of flexion.

Ankylosis. Consolidation and immobility of a joint in a particular position due to contracture.

Osteoporosis. Lack of stress on the bone causes an increase in calcium absorption, weakening the bone.

d. Nervous System.

Altered sensation caused by prolonged pressure and continual stimulation of nerves. Usually pain is felt at first and then sensation is altered, and the patient no longer senses the pain.

Peripheral nerve palsy.

e. Gastrointestinal System.

(1) Disturbance in appetite caused by the slowing of gastrointestinal tract, secondary immobility, and decreased activity resulting in anorexia.

(2) Altered digestion and utilization of nutrients resulting in constipation.

(3) Altered protein metabolism. f. Integumentary System. Risk of skin breakdown, which leads to necrosis and ulceration of tissues, especially on bony areas.

g. Urinary System.

(1) Renal calculi (kidney stones) caused by stagnation of urine in the renal pelvis and the high levels of urinary calcium.

(2) Urinary tract infections caused by urinary stasis that favors the growth of bacteria.

(3) Decreased bladder muscle tone resulting in urinary retention.

h. Metabolism.

(1) Increased risk of electrolyte imbalance. An absence of weight on the skeleton and immobility causes protein to be broken down faster than it is made, resulting in a negative nitrogen balance.

(2) Decreased metabolic rate.

(3) Altered exchange of nutrients and gases.

i. Psychosocial Functioning.

(1) Decrease in self-concept and increase in sense of powerlessness due to inability to move purposefully and dependence on someone for assistance with simple self-care activities.

(2) Body image distortions (depends on diagnosis).

(3) Decrease in sensory stimulation due to lack of activity, and altered sleep-wake pattern.

(4) Increased risk of depression, which may cause the patient to become apathetic, possibly because of decreased sensory stimulation; or the patient may exhibit altered thought processes.

(5) Decreased social interaction.