Studies of Oxygen Administration in Respiratory Failure

Abstract

Arterial PO2 [O2 pressure], PCO2 and pH were studied in 85 patients, breathing air, during acute exacerbations of chronic obstructive pulmonary disease. Most patients had O2 tensions below 60 mmHg, but only 15 had pH values less than 7.30 or PCO2 levels above 65 mmHg. In 53 patients the effect on PCO2 levels of low-flow O2, sufficient to raise PO2 to at least 60 mmHg, was studied. Increases m arterial PO2 in these patients usually led to rises in arterial PCO2. The majority of patients tolerated increases of arterial PO2 to adequate levels without developing large increases in either PCO2 or H+ concentration. Although there were wide variations in the rise in PCO2 for a given increase in PO2, patients with low initial PO2 tended to have greater PCO2 rises, in a given patient the greater the increase in PO2 the greater was the resulting increase in PCO2. A majority of patients with respiratory failure consequent to chronic obstructive respiratory disease can be managed satisfactorily during acute exacerbations with controlled low-flow O2, therapy without recourse to tracheostomy and machine-supported respiration. A suggested therapeutic approach to the management of these patients by this method is given. The necessity for repeated blood-gas analyses for arterial PO2, PCO2 and pH during their care is stressed.