Cerebral oxygen saturation changes during modified ultrafiltration

Abstract

A number of adverse effects are associated with the use of cardiopulmonary bypass (CPB) in pediatric patients undergoing cardiac surgery. Pulmonary compliance and gas exchange are decreased, and myocardial edema may result in diastolic dysfunction. Modified ultrafiltration (MUF) after CPB in children decreases body water, removes inflammatory mediators, improves hemodynamics, and decreases transfusion requirements. To determine the factors that influence cerebral tissue oxygenation during MUF. Pediatric patients received the usual treatment, with MUF times from 10 to 19 min, as determined by circuit volume and patient hemodynamic stability. Preliminary results in five patients with arterial saturation > 95% during MUF demonstrates four predictors of cerebral oxygenation, using stepwise multiple linear regression with cerebral oxygen saturation as the dependant variable. In order of significance, they are pCO2, ultrafiltration flow rate, mean arterial pressure, and hematocrit. The results of this study will be used to determine the optimal performance of MUF. Maximizing cerebral oxygen delivery during this early post-bypass period is extremely important, and identifying the factors responsible for increased cerebral oxygen delivery during MUF allows the clinician to make the appropriate changes necessary to achieve this.