The I-gel is a new single-use supraglottic airway device without an inflatable cuff. This study was designed to investigate the usefulness of the I-gel compared with the classic laryngeal mask airway (cLMA) and ProSeal laryngeal mask airway (pLMA) in anaesthetized, paralysed patients. The American Society of Anesthesiologists physical status I-II patients (n = 167) scheduled for orthopaedic surgery were included in this prospective study. General anaesthesia was achieved with intravenous infusion of propofol, remifentanil and rocuronium. The patients were randomly assigned to I-gel, pLMA and cLMA groups (64, 53 and 50 patients, respectively). Properly sized I-gel (No. 3-4) or LMA (No. 4-5) was inserted. We assessed haemodynamic data, airway leak pressure, leak volume, success rates and postoperative complications. There were no differences in the demographic data and haemodynamic data immediately after insertion of devices among the three groups. The airway leak pressures of the I-gel group (27.1 +/- 6.4 cmH2O) and pLMA group (29.8 +/- 5.7 cmH2O) were significantly higher than that of the cLMA group (24.7 +/- 6.2 cmH2O). The success rates for first attempt of insertion were similar among the three groups (P = 0.670). There were no differences in the incidence of adverse events except for the larger incidence of sore throat in the cLMA group. I-gel may have a similar airway sealing to that of pLMA, higher than that of cLMA, and is not associated with adverse events. The I-gel might be an effective alternative as a supraglottic airway device.

Although regional cerebral oxygen saturation (rSO₂) measurements can detect disturbances in cerebral oxygenation, their usefulness is limited in patients with hyperbilirubinemia. We examined the relationship between rSO₂ and other laboratory variables that may affect interpretation of low rSO₂ in awake patients with end-stage liver disease before liver transplantation surgery. Before induction of general anesthesia, rSO₂ 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 rSO₂ and laboratory variables were evaluated by correlation and multivariate regression, and by receiver operating characteristic curve analysis. Univariate analyses showed that rSO₂ (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 rSO₂ 7.2 mg/dL (sensitivity 89%, specificity 90%) and Hb <9.6 g/dL (sensitivity 70%, specificity 82%). High total bilirubin and low Hb concentrations were independently associated with rSO₂ values below 50% in end-stage liver disease patients awaiting liver transplantation. The results of this study identify patients in whom a low rSO₂ may be an artifact rather than cerebral ischemia.