Jugular Venous Oxygenation During Hypothermic Cardiopulmonary Bypass in Patients at Risk for Abnormal Cerebral Autoregulation: Influence of α-Stat Versus pH-Stat Blood Gas Management

Abstract

In Brief In a prospective, randomized study of cardiac surgical patients at risk for impaired cerebral blood flow autoregulation, we compared α-stat and pH-stat blood gas management. The 40 patients enrolled had age >70 yr, diabetes, prior stroke, or uncontrolled hypertension. During hypothermia and early rewarming, jugular oxygen tensions were significantly lower in α-stat patients (n = 12) than pH-stat patients (n = 19; P < 0.05). During rewarming, jugular venous desaturation (i.e., SjvO2 <50%) occurred in 6 of 12 α-stat patients, but no pH-stat patients (P = 0.0006). Patients at risk for poor cerebral autoregulation have higher oxygen tensions and saturations if pH-stat blood gas management is used during cardiopulmonary bypass. IMPLICATIONS: Patients at high risk for poor cerebral autoregulation during cardiopulmonary bypass have higher jugular venous oxygen tensions and saturations throughout the hypothermic period and the first minute of rewarming during cardiopulmonary bypass if pH-stat blood gas management is used instead of α-stat management.