Effect of Controlled Oxygen Therapy on Arterial Blood Gases in Acute Respiratory Failure

Seven patients in acute exacerbation of chronic respiratory failure were given 24·5% and later 28% oxygen through Ventimasks. The mean increases in arterial PO₂ were 11 and 21 mm. Hg while breathing 24·5% and 28% oxygen respectively compared with control values while breathing air. Associated increases in arterial PCO₂ were 4 and 8 mm. Hg, respectively. In five of the patients these increases in inspired oxygen concentration resulted in useful increases in tissue oxygen supply without significant deterioration in ventilation, but in two patients arterial PCO₂ rose excessively and artificial ventilation was required.