Studies made on anesthetized patients indicate that an adequate volume of pulmonary ventilation and total absorption of carbon dioxide are requisites for the prevention of respiratory acidosis.1 Oxygen desaturation seldom occurs in the presence of the high partial pressure of oxygen generally used with anesthetic gases. The altered physiologic state does not end abruptly when the patient leaves the operating room. The usual physiologic responses may remain obtunded by medicaments used preceding, during, and after operation. Blood loss, alterations in pressure relationships of the body cavities, and pain further alter the expected responses to the usual respiratory requirements, as well as the requirements themselves.
When the patient is again exposed to the ambient atmosphere, the partial pressure of oxygen is generally low as compared with that of the anesthetic gas mixture. The problem of oxygenation may supersede that of carbon dioxide elimination. We have attempted to evaluate respiratory adequacy