• K J Sapire, S P Gopinath, G Farhat, D R Thakar, A Gabrielli, J W Jones, C S Robertson, and B Chance.
• Department of Anesthesiology, Baylor College of Medicine, Houston, TX 77030-4298, USA.
• Crit. Care Med. 1997 Oct 1;25(10):1655-62.

ObjectivesTo evaluate jugular venous oxygen saturation (SjVO2), measured with a fiberoptic oximetry catheter, and brain tissue oxygen saturation, measured by near-infrared spectroscopy (NIRSO2), as monitors of cerebral oxygenation during cardiopulmonary bypass surgery.DesignProspective, clinical study.SettingOperating room of a Veterans Administration Hospital.PatientsNineteen patients undergoing moderate hypothermic cardiopulmonary bypass surgery.InterventionsSjvO2 and NIRSO2 were monitored in the patients during the surgical procedure.Measurements And Main ResultsModerate hypothermic cardiopulmonary bypass surgery had two distinct cerebral hemodynamic phases. While the patients were hypothermic, SjvO2 averaged 80 +/- 7% and none of the patients had an increase in cerebral lactate production. During the rewarming period, however, reductions in SjvO2 to < 50% occurred in 16 (84%) patients and increased cerebral anaerobic metabolism developed in 11 (58%) patients. SjvO2 during rewarming was dependent on mean arterial pressure, with 60 mm Hg appearing to be a critical value. Two other factors appeared to also contribute to the jugular desaturation, a low hematocrit and a rapid warming time. The SjvO2 catheter had excellent performance during the surgery. The average difference between paired measurements of SjvO2 by the catheter and in blood samples was -0.4 +/- 4.25%, and the correlation between the two measurements was highly significant (r2 = .93; p < .001). The NIRSO2 trended with the SjvO2 in most patients (r2 = .63; p < .001).ConclusionsThe study confirms other studies showing that jugular venous desaturation can occur during rewarming after cardiopulmonary bypass surgery. Presently, SjvO2 appears to be a better monitor of cerebral oxygenation than NIRSO2. However, NIRSO2 has promise as a noninvasive monitor of cerebral oxygenation if future developments allow more quantitative measurements of oxygen saturation.

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