Blood pressure control during eye surgery under local anesthesia using pulse oximetry

Abstract

We measured the arterial blood pressure and percutaneous O2 saturation (SpO2) in 39 elderly patients (age range, 70-89 years) who underwent cataract surgery under local anesthesia. Nineteen patients showed a 20% or greater increase in the systolic arterial pressure (SAP) measured every minute in the operating room compared to the basal value measured in the ward. We treated elevation of the SAP by intravenous bolus injection of 0.25 mg nitroglycerin (NTG), followed by continuous infusion at 0.1-0.3 microg/kg/min. NTG caused a statistically significant but clinically irrelevant decrease in SpO2 in the patients breathing room air. Two of these patients showed extremely decreased SpO2. Our results suggest that NTG does not typically cause a severe decrease in oxygenation. It might be advisable, however, for patients with severe lung dysfunction or ischemic heart disease to receive prophylactic O2 administration.