Measurement of alveolar carbon dioxide tension is important in the diagnosis and care of patients with pulmonary disease, during anesthesia, in coma, and in other conditions with increased or depressed alveolar ventilation. A previous communication1 described a simple, accurate, inexpensive apparatus for the bedside measurement of alveolar carbon dioxide tension. The present report deals with the clinical application of this method to eucapnic, hypercapnic, and hypocapnic subjects. The results are compared with simultaneous measurement of arterial blood carbon dioxide tension, and a method is outlined for use of the apparatus in patients in coma or unable to produce an adequate alveolar sample on a single breath.
Materials and Methods
Nineteen patients referred for pulmonary function studies and presenting a variety of cardiopulmonary diseases were studied. Simultaneous measurements were made of the carbon dioxide tension of their arterial blood and end-expired or rebreathing gas samples, or both.The principle of