Preoperative hypoxemia in conscious patients after subarachnoid hemorrhage

We retrospectively examined partial arterial pressure of oxygen (Pao₂) afer subarachnoid hemorrhage (SAH), adjusted for patient-related risk factors for hypoxemia in 51 adult patients with no disturbance of consciousness undergoing surgery for clipping of intracranial aneurysms. A control group of 174 patients undergoing other operations were used for comparison. Arterial blood gas analysis was performed while patients were spontaneously breathing room air in the supine position before induction of anesthesia. The Pao₂ in the SAH patients was significantly lower (p<0.0001) than that in the control group after adjustment for age, obesity, and smoking status. In three patients in the SAH group, Pao₂ was less than 60 mmHg. Close monitoring of arterial oxygenation with pulse oximetry is desirable, and supplemental oxygen should be considered during transfer from the patients' room to the operating suite, even for conscious patients of SAH without cardiopulmonary disease.