Cerebral and peripheral oxygen saturation during red cell transfusion

Abstract

Background. Changes in regional hemoglobin oxygen saturation occur in response to blood transfusion and can be measured by near infrared spectroscopy. Patients and methods. Cerebral (CsO 2) and peripheral (PsO 2) oxygen saturation were monitored with an INVOS 4100 near infrared spectroscopy oximeter in 29 patients undergoing 84 intraoperative blood transfusions during aortic or spinal surgery. Hemoglobin concentration was measured before and after transfusion. Mean arterial pressure, end tidal carbon dioxide tension, and arterial oxygen saturation were also monitored. Results. Mean arterial pressure, arterial oxygen saturation and end tidal carbon dioxide tension remained stable during transfusion, while CsO 2 rose by a mean (95% CI) of 4.2 (3.2–5.2%; P = 0.001) and PsO 2 rose by a mean (95% CI) of 1.6 (0.3–2.8%; P = 0.016). The rise in CsO 2 correlated well with the rise in hemoglobin ( r = 0.59, P < 0.001) and with the volume transfused ( r = 0.58, P < 0.001). PsO 2 correlated with the volume transfused ( r = 0.35, P = 0.019) but not with hemoglobin concentration ( r = 0.08, P = 0.47). Conclusions. Near infrared spectroscopy detected significant rises in tissue oxygenation in response to blood transfusion, particularly in the cerebral cortex. CsO 2 may be developed into a blood loss monitor if further research confirms our findings.