释义 |
respiratory failure
respiratory failuren. An acute or chronic condition marked by severely impaired pulmonary function, characterized by elevated carbon dioxide or decreased oxygen, or both, in the arterial blood and often by the necessity of a ventilator to assist breathing.respiratory failure n (Medicine) a condition in which the respiratory system is unable to provide an adequate supply of oxygen or to remove carbon dioxide efficiently EncyclopediaSeefailurerespiratory failure
Respiratory Failure DefinitionRespiratory failure is nearly any condition that affects breathing function or the lungs themselves and can result in failure of the lungs to function properly. The main tasks of the lungs and chest are to get oxygen from the air that is inhaled into the bloodstream, and, at the same to time, to eliminate carbon dioxide (CO2) from the blood through air that is breathed out. In respiratory failure, the level of oxygen in the blood becomes dangerously low, and/or the level of CO2 becomes dangerously high. There are two ways in which this can happen. Either the process by which oxygen and CO2 are exchanged between the blood and the air spaces of the lungs (a process called "gas exchange") breaks down, or the movement of air in and out of the lungs (ventilation) does not take place properly.DescriptionRespiratory failure often is divided into two main types. One of them, called hypoxemic respiratory failure, occurs when something interferes with normal gas exchange. Too little oxygen gets into the blood (hypoxemia), and all organs and tissues in the body suffer as a result. One common type of hypoxemic failure, occurring in both adults and prematurely born infants, is respiratory distress syndrome, a condition in which fluid or tissue changes prevent oxygen from passing out of the air sacs of the lungs into the circulating blood. Hypoxemia also may result from spending time at high altitudes (where there is less oxygen in the air); various forms of lung disease that separate oxygen from blood in the lungs; severe anemia ("low blood"); and blood vessel disorders that shunt blood away from the lungs, thus precluding the lungs from picking up oxygen.The other main type of respiratory failure is ventilatory failure, occurring when, for any reason, breathing is not strong enough to rid the body of CO2. Then CO2 builds up in the blood (hypercapnia). Ventilatory failure can result when the respiratory center in the brainstem fails to drive breathing; when muscle disease keeps the chest wall from expanding when breathing in; or when a patient has chronic obstructive lung disease that makes it very difficult to exhale air with its CO2. Many of the specific diseases and conditions that cause respiratory failure cause both too little oxygen in the blood (hypoxemia) and abnormal ventilation.Causes and symptomsSeveral different abnormalities of breathing function can cause respiratory failure. The major categories, with specific examples of each, are:- Obstruction of the airways. Examples are chronic bronchitis with heavy secretions; emphysema; cystic fibrosis; asthma (a condition in which it is very hard to get air in and out through narrowed breathing tubes).
- Weak breathing. This can be caused by drugs or alcohol, which depress the respiratory center; extreme obesity; or sleep apnea, where patients stop breathing for long periods while sleeping.
- Muscle weakness. This can be caused by a muscle disease called myasthenia; muscular dystrophy; polio; a stroke that paralyzes the respiratory muscles; injury of the spinal cord; or Lou Gehrig's disease.
- Lung diseases, including severe pneumonia. Pulmonary edema, or fluid in the lungs, can be the source of respiratory failure. Also, it can often be a result of heart disease; respiratory distress syndrome; pulmonary fibrosis and other scarring diseases of the lung; radiation exposure; burn injury when smoke is inhaled; and widespread lung cancer.
- An abnormal chest wall (a condition that can be caused by scoliosis or severe injury of the chest wall).
A majority of patients with respiratory failure are short of breath. Both low oxygen and high carbon dioxide can impair mental functions. Patients may become confused and disoriented and find it impossible to carry out their normal activities or do their work. Marked CO2 excess can cause headaches and, in time, a semi-conscious state, or even coma. Low blood oxygen causes the skin to take on a bluish tinge. It also can cause an abnormal heart rhythm (arrhythmia). Physical examination may show a patient who is breathing rapidly, is restless, and has a rapid pulse. Lung disease may cause abnormal sounds heard when listening to the chest with a stethoscope: wheezing in asthma, "crackles" in obstructive lung disease. A patient with ventilatory failure is prone to gasp for breath, and may use the neck muscles to help expand the chest.DiagnosisThe symptoms and signs of respiratory failure are not specific. Rather, they depend on what is causing the failure and on the patient's condition before it developed. Good general health and some degree of "reserve" lung function will help see a patient through an episode of respiratory failure. The key diagnostic determination is to measure the amount of oxygen, carbon dioxide, and acid in the blood at regular intervals. A sudden low oxygen level in the lung tissue may cause the arteries of the lungs to narrow. This, in turn, causes the resistance in these vessels to increase, which can be measured using a special catheter. A high blood level of CO2 may cause increased pressure in the fluid surrounding the brain and spinal cord; this, too, can be measured.TreatmentNearly all patients are given oxygen as the first treatment. Then the underlying cause of respiratory failure must be treated. For example, antibiotics are used to fight a lung infection, or, for an asthmatic patient, a drug to open up the airways is commonly prescribed.A patient whose breathing remains very poor will require a ventilator to aid breathing. A plastic tube is placed through the nose or mouth into the windpipe and is attached to a machine that forces air into the lungs. This can be a lifesaving treatment and should be continued until the patient's own lungs can take over the work of breathing. It is very important to use no more pressure than is necessary to provide sufficient oxygen; otherwise ventilation may cause further lung damage. Drugs are given to keep the patient calm, and the amount of fluid in the body is carefully adjusted so that the heart and lungs can function as normally as possible. Steroids, which combat inflammation, may sometimes be helpful but they can cause complications, including weakening the breathing muscles.The respiratory therapist has a number of methods available to help patients overcome respiratory failure. They include:- Suctioning the lungs through a small plastic tube passed through the nose, in order to remove secretions from the airways that the patient cannot cough up.
- Postural drainage, in which the patient is propped up at an angle or tilted to help secretions drain out of the lungs. The therapist may clap the patient on the chest or back to loosen the secretions, or a vibrator may be used for the same purpose.
- Breathing exercises often are prescribed after the patient recovers. They make the patient feel better and help to strengthen the muscles that aid breathing. One useful method is for the patient to suck on a tube attached to a clear plastic hosing containing a ball so as to keep the ball lifted. Regular deep breathing exercises are simpler and often just as helpful. Another technique is to have the patient breathe out against pursed lips to increase pressure in the airways and keep them from collapsing.
PrognosisThe outlook for patients with respiratory failure depends chiefly on its cause. If the underlying disease can be effectively treated, with the patient's breathing supported in the meantime, the outlook is usually good.Care is needed not to expose the patient to polluting substances in the atmosphere while recovering from respiratory failure; this could tip the balance against recovery. When respiratory failure develops slowly, pressure may build up in the lung's blood vessels, a condition called pulmonary hypertension. This condition may damage the vessels, worsen hypoxemia, and cause the heart to fail. If it is not possible to provide enough oxygen to the body, complications involving either the brain or the heart may prove fatal.If the kidneys fail or the diseased lungs become infected, the prognosis is worse. In some cases, the primary disease causing the lungs to fail is irreversible. The patient, family, and physician together then must decide whether to prolong life by ventilator support. Occasionally, lung transplantation is a possibility, but it is a highly complex procedure and is not widely availablePreventionBecause respiratory failure is not a disease itself, but the end result of many lung disorders, the best prevention is to treat any lung disease promptly and effectively. It is also important to make sure that any patient who has had lung disease is promptly treated for any respiratory infection (even of the upper respiratory tract). Patients with lung problems should also avoid exposure to pollutants, as much as is possible. Once respiratory failure is present, it is best for a patient to receive treatment in an intensive care unit, where specialized personnel and all the needed equipment are available. Close supervision of treatment, especially mechanical ventilation, will help minimize complications that would compound the problem.ResourcesOrganizationsNational Heart, Lung and Blood Institute. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.National Respiratory Distress Syndrome Foundation. P.O. Box 723, Montgomeryville, PA 18936.Key termsChronic obstructive lung disease — A common form of lung disease in which breathing, and therefore gas exchange, is labored and increasingly difficult.Gas exchange — The process by which oxygen is extracted from inhaled air into the bloodstream, and, at the same time, carbon dioxide is eliminated from the blood and exhaled.Hypoxemia — An abnormally low amount of oxygen in the blood, the major consequence of respiratory failure, when the lungs no longer are able to perform their chief function of gas exchange.Pulmonary fibrosis — An end result of many forms of lung disease (especially chronic inflammatory conditions). Normal lung tissue is converted to scarred, "fibrotic" tissue that cannot carry out gas exchange.failure [fāl´yer] inability to perform or to function properly.adult failure to thrive a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as a progressive functional deterioration of a physical and cognitive nature. The individual's ability to live with multisystem diseases, cope with ensuing problems, and manage his/her care are remarkably diminished.bone marrow failure failure of the hematopoietic function of the bone marrow; see also suppression" >bone marrow suppression.congestive heart failure see heart failure" >congestive heart failure.heart failure see heart failure.kidney failure renal failure.multiple organ failure failure of two or more organ systems in a critically ill patient; see also multiple organ failure.renal failure see renal failure.respiratory failure see respiratory failure.failure to thrive (failure to thrive syndrome) physical and developmental retardation in infants and small children. The syndrome can be seen in children with a physical illness, but the term is most often taken to mean failure to thrive due to psychosocial effects such as maternal deprivation. The syndrome was first noticed when European psychiatrists studied the development of babies who had spent the first five years of their lives in institutions where they were deprived of the emotional warmth of a mother, father, or other primary caregiver. Characteristics of the failure to thrive syndrome include lack of physical growth (for example, weight and height below the third percentile for age) and below normal achievement in fine and gross motor, social-adaptive, and language skills as assessed by psychometric testing using a tool such as the Denver Developmental Screening Test. Additionally, the child with this syndrome displays withdrawing behavior, avoidance of eye contact, and stiffness or flaccid posture when held. These children often have a history of irritability, feeding problems, and disturbed sleep patterns. Parents of infants with failure to thrive syndrome typically display feelings of concern and inadequacy. The infant who is feeding poorly and is irritable may elicit a response in the caregiver that reflects tension and frustration. The need for comfort and nurturing by the infant may not be met, and this may lead to a cycle that exacerbates feeding problems. Intervention encompasses identification of infants and mothers at risk for the syndrome and care of both mother or primary caregiver and infant. The major goals are to encourage the mother to express her feelings without fear of rejection, to model the role of mother and teach her nurturing behaviors, and to promote her self-esteem and confidence. Important nursing goals in the care of the infant include providing optimal nutrition, comfort, and rest; meeting the infant's psychosocial needs; and supplying emotional nurturance and sensory stimulation appropriate to the assessed developmental level.ventilatory failure respiratory failure.
respiratory [res´pir-ah-tor″e] pertaining to respiration.acute respiratory distress syndrome (adult respiratory distress syndrome) a group of symptoms accompanying fulminant pulmonary edema and resulting in acute respiratory failure; see also acute respiratory distress syndrome.respiratory care 1. the health care profession providing, under qualified supervision, diagnostic evaluation, therapy, monitoring, and rehabilitation of patients with cardiopulmonary disorders; it also employs educational activities to support patients and their families and to promote cardiovascular health among the general public.2. the care provided by members of this profession.3. the diagnostic and therapeutic use of medical gases and their administering apparatus, environmental control systems, humidification, aerosols, medications, ventilatory support, bronchopulmonary drainage, pulmonary rehabilitation, cardiopulmonary resuscitation, and airway management.respiratory distress syndrome, neonatal (respiratory distress syndrome of the newborn (RDS)) a condition of the newborn marked by dyspnea with cyanosis, heralded by such prodromal signs as dilatation of the nares, grunting on exhalation, and retraction of the suprasternal notch or costal margins. It usually occurs in newborns who are preterm, have diabetic mothers, or were delivered by cesarean section; sometimes there is no apparent predisposing cause.
This is the major cause of death in neonates and survivors have a high risk for chronic neurologic complications. No one factor is known to cause the condition; however, prematurity and interrupted development of the surfactant" >surfactant system is thought to be the major causative factor. Surfactant is secreted by the epithelial cells of the alveoli. It acts as a detergent, decreasing the surface tension of fluids that line the alveoli and bronchioles and allowing for uniform expansion of the lung and maintenance of lung expansion. When there is an inadequate amount of surfactant, a great deal of effort is required to re-expand the alveoli with air; thus the newborn must struggle for each breath. Insufficient expansion of the alveoli results in partial or complete collapse of the lung (atelectasis). This in turn produces hypoxemia and elevated serum carbon dioxide levels. The hypoxemia causes metabolic acidosis from increased production of lactic acid and respiratory acidosis due to the hypercapnia. The lowered pH constricts pulmonary blood vessels and inhibits intake of oxygen, thus producing more hypoxemia and interfering with the transport of substances necessary for the production of the sorely needed surfactant.Patient Care. In order to minimize the hazards of oxygen toxicity and retinopathy of prematurity" >retinopathy of prematurity, the blood gases of the newborn with respiratory distress syndrome must be carefully monitored to assess response to therapy. The goal is to administer only as much oxygen as is necessary to maintain an optimal level of oxygenation.
To improve respiratory function, intubation, suctioning of the air passages, and pressure" >continuous positive airway pressure via nasal prongs are commonly used, as well as instillation of artificial surfactant. Monitoring is conducted using monitoring" >transcutaneous oxygen monitoring or a pulse oximeter. To optimize breathing effort and facilitate air exchange, the newborn is positioned on the back with a shoulder support to keep the neck slightly extended, or on the side with the head supported. Because of the drying effect of oxygen therapy and the prohibition of oral fluids, mouth care must be given frequently to prevent drying and cracking of the lips and oral mucosa.respiratory failure a life-threatening condition in which respiratory function is inadequate to maintain the body's need for oxygen supply and carbon dioxide removal while at rest; it usually occurs when a patient with chronic airflow limitation develops an infection or otherwise suffers an additional strain on already seriously impaired respiratory functions. Inadequate or unsuccessful treatment of respiratory insufficiency from a variety of causes can lead to respiratory failure. Called also ventilatory failure.
Early symptoms include dyspnea, wheezing, and apprehension; cyanosis is rarely present. As the condition worsens the patient becomes drowsy and mentally confused and may slip into a coma. blood gas analysis is an important tool in diagnosing respiratory failure and assessing effectiveness of treatment. The condition is a medical emergency that can rapidly progress to irreversible cardiopulmonary failure and death. Treatment is concerned with improving ventilation and oxygenation of tissues, restoring and maintaining fluid balance and acid-base balance, and stabilizing cardiac function.respiratory insufficiency a condition in which respiratory function is inadequate to meet the body's needs when increased physical activity places extra demands on it. Insufficiency occurs as a result of progressive degenerative changes in the alveolar structure and the capillary tissues in the pulmonary bed, as, for example, in chronic airflow limitation and fibrosis" >pulmonary fibrosis. Treatment is essentially supportive and symptomatic. If the condition is not successfully managed it may progress to respiratory failure.respiratory therapist a health care professional skilled in the treatment and management of patients with respiratory problems, who administers respiratory care. The minimum educational requirement is an associate degree, providing knowledge of anatomy, physiology, pharmacology, and medicine sufficient to serve as a supervisor and consultant. Those registered by the National Board for Respiratory Therapy are designated Registered Respiratory Therapist (RRT).respiratory therapy respiratory care.respiratory therapy technician a health care professional who has completed a specialized one- or two-year educational program and who performs routine care, management, and treatment of patients with respiratory problems under the supervision of a respiratory therapist. Such programs are usually found in community colleges and are accredited by the Joint Review Committee for Respiratory Therapy Education.respiratory failureloss of pulmonary function either acute or chronic that results in hypoxemia or hypercarbia; final common pathway for myriad respiratory disorders.respiratory failuren. An acute or chronic condition marked by severely impaired pulmonary function, characterized by elevated carbon dioxide or decreased oxygen, or both, in the arterial blood and often by the necessity of a ventilator to assist breathing.res·pi·ra·tory fail·ure (res'pir-ă-tōr-ē fāl'yŭr) Loss of pulmonary function, either acute or chronic, that results in hypoxemia or hypercarbia; final common pathway for many respiratory disorders. res·pi·ra·tory fail·ure (res'pir-ă-tōr-ē fāl'yŭr) Loss of pulmonary function, either acute or chronic; final common pathway for myriad respiratory disorders. |