Agreement of noninvasive cerebral oxygenation with mixed venous oxygen saturation in patients undergoing ECMO-therapy

Purpose: Approximately 1% of patients require temporary circulatory support due to cardiogenic shock following cardiac surgery. These patients are at risk of a mismatch between oxygen delivery and demand and carry a substantial mortality and morbidity risk. Mixed venous oxygen saturation (SvO2) is the still the “gold standard” for the determination of the ratio between systemic oxygen delivery and consumption (DO2/VO2 ratio) in cardiac surgery patients. A noninvasive technique is thought to be cerebral near-infrared spectroscopy determining cerebral oxygen saturation (ScO2). The present analysis aims to compare ScO2 and SvO2 in adult patients undergoing ECMO therapy for postoperative cardiogenic shock.Methods: Data were collected hourly for the first 24 hours postoperatively. Each patient was equipped with a pulmonary artery catheter (PAC) connected to a Vigilance II monitor (Edwards Lifesciences, Irvine, USA) for continuous determination of SvO2 and an INVOS 5100 monitoring system (Somanetics, Troy, USA) to determine ScO2. Data were analyzed by parametric testing and Bland-Altman analysis.Results: 10 consecutive patients were included in this prospective, observational study. SvO2 and ScO2 did not differ significantly throughout the observation period. Bland-Altman analysis showed a mean difference (bias) of 2,37 % and limits of agreement of 13,72 % to -8,99 %Conclusions: These data suggest that ScO2 does not differ significantly from SvO2 in patients undergoing ECMO therapy for postoperative cardiogenic shock and may thus be a noninvasive alternative to monitor the DO2/VO2 ratio during this condition.