Infusion rate of propofol and jugular venous oxygen saturation.

We compared jugular venous blood oxygen saturation (Sj(O) (2)) and the arterial-to-jugular-bulb venous oxygen content difference (AjD(O) (2)) between bispectral index (BIS) values of 40 and 60, adjusted by the infusion rate of propofol. Eighteen postoperative neurosurgical patients (Glasgow Coma Scale [GCS] scores, 11-15) were enrolled. Normocapnia, normothermia, and a mean arterial blood pressure greater than 70 mmHg were maintained. At BIS values of 40 and 60, hemoglobin, oxygen saturation, and the oxygen partial pressure of arterial and jugular venous blood were measured. Sj(O) (2) at BIS40 (58 +/- 9%) was significantly (P < 0.01) lower than that at BIS60 (63 +/- 10%), and AjD(O) (2) at BIS40 (6.3 +/- 1.5 ml.dl(-1)) was significantly (P < 0.01) higher than that at BIS60 (5.7 +/- 1.5 ml.dl(-1); mean +/- SD). At BIS40, status defined as Sj(O) (2) less than 50% was observed in 3 patients, while this status was observed in 1 patient at BIS60. In conclusion, in patients with postoperative neurosurgical surgery (GCS scores, 11-15), decreases of propofol infusion to adjust the BIS value from 40 to 60 increase the cerebral oxygen balance.