Hyperbaric Oxygen Therapy Benefits And Side Effects.....
Oxygen, a--gas forming 20 per cent of air, is necessary for virtually all mammalian metabolism and without it human life cannot continue. When air is breathed, haemoglobin is only 97 per cent saturated with oxygen, but if 100 per cent oxygen is breathed instead, haemoglobin becomes fully saturated and nitrogen, which forms 80 per cent of air, is washed out of the lungs and replaced by oxygen. Excess oxygen is dissolved in the plasma and thus reaches the tissues in greater than normal amounts and gradually eliminates all nitrogen.
Oxygen deprivation is most disastrous initially to highly developed tissues and organs. Thus, the brain, the most specialised organ, dies if deprived of oxygen for more than four to five minutes, and brief cerebral hypoxia, as occurs in common syncope or fainting, causes temporary unconsciousness. Conversely, the less highly developed tissues of the limbs can stand more prolonged oxygen deprivation, which is demonstrated.by their resistance to hypoxia following application of tourniquets to cut off blood supply during orthopaedic operations.
Oxygen administration helps in conditions featuring hypoxia, occurring:
( I ) When breathing is impaired.
(a) In partial obstruction of the airways, as may occur in tumors or inflammation of the larynx or trachea.
(b) In respiratory inadequacy from muscular weakness, which occurs in some diseases of the nervous system.
(2) In disease of the lungs which diminishes diffusion of oxygen to the blood. Examples are severe bronchitis, chronic bronchitis with emphysema, acute pneumonia, or heart failure with con-sequent pulmonary oedema. In the treatment of these conditions it is imports tit that the inspired air should not be enriched with more than 30 per cent oxygen without specific medical instruct-tions, as inhalation of higher concentrations of oxygen can cause respiratory arrest because of abolition of the anorexic drive from I he photoreceptor in the patent's carotid sinuses.
breathing air or oxygen at normal pressure, so extra oxygen is available to the tissues.
There are two methods of giving hyperbolic oxygen therapy. In the first the patient is enclosed in a single-person hyperbolic oxygen chamber (see Fig. 47/2), which is filled and ventilated with 100 per cent oxygen at a pressure greater than atmospheric, usually two or three atmospheres absolute (atmospheric pressure equals one atmosphere absolute). Thus the patient breathes oxygen at this increased pressure.
In the second method, the patient and medical and nursing staff are enclosed within a large chamber which is filled and ventilated with air compressed to similar pressure. The patient, however, breathes 100 per cent oxygen from a mask or via an interracial tube (depending on whether conscious or anaes¬thetized), while the medical staff breathe compressed air. In these condi¬tions the oxygen breathed by the patient is at the same pressure as that to which the air in the chamber is compressed.
Oxygen, a--gas forming 20 per cent of air, is necessary for virtually all mammalian metabolism and without it human life cannot continue. When air is breathed, haemoglobin is only 97 per cent saturated with oxygen, but if 100 per cent oxygen is breathed instead, haemoglobin becomes fully saturated and nitrogen, which forms 80 per cent of air, is washed out of the lungs and replaced by oxygen. Excess oxygen is dissolved in the plasma and thus reaches the tissues in greater than normal amounts and gradually eliminates all nitrogen.
Oxygen deprivation is most disastrous initially to highly developed tissues and organs. Thus, the brain, the most specialised organ, dies if deprived of oxygen for more than four to five minutes, and brief cerebral hypoxia, as occurs in common syncope or fainting, causes temporary unconsciousness. Conversely, the less highly developed tissues of the limbs can stand more prolonged oxygen deprivation, which is demonstrated.by their resistance to hypoxia following application of tourniquets to cut off blood supply during orthopaedic operations.
Oxygen administration helps in conditions featuring hypoxia, occurring:
( I ) When breathing is impaired.
(a) In partial obstruction of the airways, as may occur in tumors or inflammation of the larynx or trachea.
(b) In respiratory inadequacy from muscular weakness, which occurs in some diseases of the nervous system.
(2) In disease of the lungs which diminishes diffusion of oxygen to the blood. Examples are severe bronchitis, chronic bronchitis with emphysema, acute pneumonia, or heart failure with con-sequent pulmonary oedema. In the treatment of these conditions it is imports tit that the inspired air should not be enriched with more than 30 per cent oxygen without specific medical instruct-tions, as inhalation of higher concentrations of oxygen can cause respiratory arrest because of abolition of the anorexic drive from I he photoreceptor in the patent's carotid sinuses.
breathing air or oxygen at normal pressure, so extra oxygen is available to the tissues.
There are two methods of giving hyperbolic oxygen therapy. In the first the patient is enclosed in a single-person hyperbolic oxygen chamber (see Fig. 47/2), which is filled and ventilated with 100 per cent oxygen at a pressure greater than atmospheric, usually two or three atmospheres absolute (atmospheric pressure equals one atmosphere absolute). Thus the patient breathes oxygen at this increased pressure.
In the second method, the patient and medical and nursing staff are enclosed within a large chamber which is filled and ventilated with air compressed to similar pressure. The patient, however, breathes 100 per cent oxygen from a mask or via an interracial tube (depending on whether conscious or anaes¬thetized), while the medical staff breathe compressed air. In these condi¬tions the oxygen breathed by the patient is at the same pressure as that to which the air in the chamber is compressed.
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