Laboratory variables associated with low near-infrared cerebral oxygen saturation in icteric patients before liver transplantation surgery.

摘要

BACKGROUND: Although regional cerebral oxygen saturation (rSO(2)) measurements can detect disturbances in cerebral oxygenation, their usefulness is limited in patients with hyperbilirubinemia. We examined the relationship between rSO(2) and other laboratory variables that may affect interpretation of low rSO(2) in awake patients with end-stage liver disease before liver transplantation surgery. METHODS: Before induction of general anesthesia, rSO(2) was measured in 164 patients with liver cirrhosis (Child class A/B/C = 19/41/104) and 8 with fulminant hepatic failure. Patients with West Haven hepatic encephalopathy of grade 3 or 4 were excluded. Relationships between rSO(2) and laboratory variables were evaluated by correlation and multivariate regression, and by receiver operating characteristic curve analysis. RESULTS: Univariate analyses showed that rSO(2) (median 58.5%, range 15% to 82%) correlated with serum total bilirubin, hemoglobin (Hb), creatinine, sodium, and magnesium concentrations, and prothrombin time (P < 0.001 each), but not with serum concentrations of glucose, albumin, potassium, and ammonia. Multiple logistic regression analysis showed that only elevated total bilirubin (range 0.4 to 66 mg/dL; odds ratio [OR] = 1.31; 95% confidence interval [CI] = 1.18 to 1.45) and low Hb (range 5.3 to 15.7 g/dL; OR = 0.21; 95% CI = 0.11 to 0.43) were independently related to rSO(2) <50%. The optimum cutoff points for observing an rSO(2) <50% were total bilirubin >7.2 mg/dL (sensitivity 89%, specificity 90%) and Hb <9.6 g/dL (sensitivity 70%, specificity 82%). CONCLUSIONS: High total bilirubin and low Hb concentrations were independently associated with rSO(2) values below 50% in end-stage liver disease patients awaiting liver transplantation. The results of this study identify patients in whom a low rSO(2) may be an artifact rather than cerebral ischemia.