Respiratory alkalosis with especial reference to chest pain.

Respiratory alkalosis may be defined as a state of altered physiochemical processes due to the excessive loss of carbon dioxide through overbreathing. Though this condition is usually referred to as the hyperventilation syndrome, respiratory alkalosis would be more accurate terminology as hyperventilation may occur as a necessary physiologic requirement without producing an alkalotic state. That the syndrome of respiratory alkalosis (hyperventilation syndrome) is being recognized with increasing frequency is attested by the numerous reports appearing in the literature. Detailed discussions of the biochemical and clinical changes incident to overbreathing may be found in the reports of Stead and Warren,’ Engle, Ferris and Logan2 as well as Ferris3 and his group. It is not within the scope of this paper to discuss all of the facets of the syndrome but rather to stress some of the clinical findings which are believed to be important in the production of symptoms. The major biochemical change occurring in this condition is the alkalosis produced by the reduction of plasma carbonic acid through excessive loss of carbon dioxide. Thus the alkalosis is relative rather than absolute. Ferris3 and his co-workers demonstrated that a single deep breath could reduce the carbon dioxide arterial concentration 5-7 volumes per cent and the carbon dioxide tension as much as 16 mm. of mercury. Symptoms of respiratory alkalosis therefore may develop rapidly and depending on the rate and volume of breathing they vary markedly from time to time. Indeed the symptoms of respiratory alkalosis are so varied and bizarre that a clinical pattern is difficult to recognize. With experience and awareness however, the condition becomes manifest. #{149} As has been pointed out by Lewis4 and others, not all cases of respiratory alkalosis are psychogenic in origin but it seems agreed that the great majority of people who hyperventilate unnecessarily do so as an expression of an emotional disturbance regardless of the presence or absence of organic disease. Thus a cardiac patient may complain of shortness of breath, pains in the chest and “poor circulation” as a result of his alkalosis rather than his heart disease. The clinician familiar with the syndrome of respiratory alkalosis will usually have little difficulty in detecting the true nature of the complaints. The earlier articles on this subject described the acute overt attack of hyperventilation with severe symptoms, the patient being in an alarming state bordering on, if not in, tetany. While this type of case is seen