Blood-gas and hemodynamic responses to oxygen in acute myocardial infarction.

Blood-gas (Pao2) and hemodynamic responses to the inhalation of oxygen were studied in 60 patients with acute myocardial infarction. Patients who were not in heart failure on admission and did not develop signs of heart failure with n the next 5 days achieved the same Pa02 level while breathing 100% oxygen as did patients without acute myocardial infarction. Patients with pulmonary edema or cardiogenic shock had a very poor Pa02 response to oxygen inhalation. Patients in mild heart failure at the time of study and patients who developed heart failure subsequent to the study had a Pao0 response intermeliate between the other two groups. This rise of Pa02 with oxygen correlated with the cardiac index and right atrial oxygen prior to inhalation of