Cerebral Near-Infrared Spectroscopy in Adult Patients After Cardiac Surgery Is Not Useful for Monitoring Absolute Values But May Reflect Trends in Venous Oxygenation Under Clinical Conditions

Objective: Cerebral near-infrared spectroscopy (NIRS) was evaluated for use in monitoring global oxygenation in adult patients after cardiac surgery.Design: Prospective, randomized clinical monitoring study.Setting: Intensive care unit for cardiac surgery; university hospital.Participants: The study included 35 patients scheduled for cardiac surgery with insertion of a pulmonary artery catheter; patients with known cerebral-vascular perfusion disturbances were excluded.Interventions: Noninvasive cerebral NIRS oxygen saturation (rSO2) and conventional intensive care monitoring parameters were assessed.Measurements and Main Results: Simple regression analysis was used to assess the correlation of rSO2 to hemodynamic parameters. There was fair-to-moderate intersubject correlation to hemoglobin concentration (r = 0.45, p < 0.0001) and mixed venous oxygen saturation (SmvO2) (r = 0.33, p < 0.0001). Sensitivity and specificity of rSO2 to detect substantial (≥1 standard deviation) changes in mixed venous oxygen saturation were 94% and 81%, respectively.Conclusions: Cerebral NIRS in adult patients might not be the tool to replace mixed venous oxygen monitoring. Further work has to be done to assess its potential to reflect intraindividual trends.