There are two immediate objectives in the treatment of patients with acute coronary thrombosis, namely the support of the circulation and the relief of pain. The beneficial effects of oxygen administration in sustaining cardiorespiratory function, especially when significant degrees of shock or pulmonary edema exist, are well known. It is not widely recognized, however, that the inhalation of oxygen in high concentrations is effective in alleviating the pain associated with coronary thrombosis and angina pectoris.
The pain associated with coronary thrombosis is notoriously variable in intensity. Its severity depends on the size of the coronary artery occluded, the speed of occlusion, the adequacy of coronary arterial anastomoses, the activity to which the myocardium is subjected, the sensitivity of the patient to pain, and other factors. Pain may be entirely absent1 or so mild that the underlying pathologic state is overlooked. In the vast majority of instances it is adequately