[Effects of theophylline on the course of hypercapnic respiratory insufficiency]

We studied 5 patients affected by respiratory failure from chronic obstructive pulmonary disease to detect the effect of theophylline on arterial gas pressures of oxygen and carbon dioxide and on mechanism of oxygen transportation. Theophylline was found to increase hemoglobin saturation and decrease carbon dioxide pressures without significant effects on the overall efficiency of pulmonary gas exchange. No differences of intraerythrocytic 2,3 diphosphoglyceric acid and plasmatic phosphate have been found. Moreover, theophylline induced a significant decrease of P50 in vivo. In summary, the main effect of xanthines seems to be an increase of sensitivity of respiratory control system possibly coupled to an increase of the efficiency of respiratory muscles.