Correlation of Noninvasive Cerebral Oxygenation with Mixed Venous Oxygen Saturation in Patients undergoing ECMO-Therapy - A Pilot Study

摘要

Approximately 1% of patients require temporary circulatory support due to cardiogenic shock following cardiac surgery. These patients afa 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. However, in patients undergoing prolonged extracorporeal membrane oxygenation (ECMO), a noninvasive and continuous technique for early detection of a systemic DO2/VO2 ratio would be desirable. One such technique is thought to be cerebral near-infrared spectroscopy (cNIRS) determining cerebral oxygen saturation (rSO2). The present analysis aims to compare rSO2 and SvO2 levels in adult patients undergoing ECMO therapy for postoperative cardiogenic shock. Data were collected hourly for the first 24 hours post operatively. Each patient was equipped with a pulmonary artery catheter (PAC) for continuous determination of SvO2 connected to a Vigilance II* - monitor (Edwards Lifesciences, Irvine, USA) and an INVOS 5100 monitoring system (Somanetics, Troy, USA) to determine rSO2. Data were analyzed by parametric testing and Bland-Altman analysis. Up to now 5 patients could be included in this ongoing prospective, observational study. SvO2 and rSO2 did not change significantly throughout the observation period. The correlation coefficient between both methods was 0.96 (95% CI: 0.98 to 0.99; p < 0.0001). Bland-Altman analysis showed a mean difference (bias) of-0.16% and limits of agreement of 0.06% to -0.39. These data suggest for the first time that rSO2 highly correlates with SvO2 in patients undergoing ECMO therapy and therefore determining rSO2 may be a noninvasive alternative to monitor the DO2/VO2 ratio during this condition.