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Background: Head fixation can induce hemodynamic instability. Remifentanil is commonly used with propofol for total intravenous anesthesia (TIVA) during neurosurgery. This study investigated the 90% effective concentration (EC90) of remifentanil for blunting of cardiovascular responses to head fixation during neurosurgery via bispectral index (BIS) monitoring. Methods: Fifty patients undergoing neurosurgery requiring head fixation were enrolled. This study was performed using the biased coin up-and-down design sequential method (BCD). After tracheal intubation, the effect-site target concentration (Ce) of remifentanil was adjusted to achieve hemodynamic stability and reset to the level preoperatively assigned to each patient, according to the BCD method, approximately 10 min before head fixation. Baseline hemodynamic values were recorded before head fixation. An ineffective response was defined as a case with a > 20% increase in hemodynamic values from baseline. Otherwise, the response was determined to be effective. The EC90 of remifentanil was calculated as a modified isotonic estimator. Results: Forty-three patients completed this study. The EC90 of remifentanil for blunting cardiovascular responses to head fixation was estimated to be 6.48 ng/mL (95% CI, 5.94-6.83 ng/mL). Conclusions: Adjustment of the Ce of remifentanil to approximately 6.5 ng/mL before head fixation could prevent noxious cardiovascular responses in 90% of neurosurgical ASA I-II patients aged 20 to 65 years old during propofol target-controlled infusion titrated to maintain BIS between 40 and 50. Trial registration: ClinicalTrials.gov Identifier NCT01489137, retrospectively registered 5 December 2011. [ABSTRACT FROM AUTHOR]

Background: Palonosetron is a recently introduced 5-hydroxytryptamine-3 (5-HT3) receptor antagonist useful for postoperative nausea and vomiting prophylaxis. However, 5-HT3 receptor antagonists increase the corrected QT (QTc) interval in patients who undergo general anesthesia. This retrospective study was performed to evaluate whether palonosetron would induce a QTc prolongation in patients undergoing general anesthesia with sevoflurane. Methods: We reviewed a database of 81 patients who underwent general anesthesia with sevoflurane. We divided the records into palonosetron (n = 41) and control (n = 40) groups according to the use of intraoperative palonosetron, and analyzed the electrocardiographic data before anesthesia and 30, 60, 90, and 120 min after skin incision. Changes in the QTc interval from baseline, mean blood pressure, heart rate, body temperature, and sevoflurane concentrations at each time point were compared between the two groups. Results: The QTc intervals at skin incision, and 30, 60, 90, and 120 min after the skin incision during general anesthesia were significantly longer than those at baseline in the two groups (P < 0.001). The changes in the QTc intervals were not different between the two groups (P = 0.41). However, six patients in the palonosetron group showed a QTc interval > 500 ms 30 min after skin incision, whereas no patient did in the control group (P = 0.01). No significant differences were observed between the two groups in mean blood pressure, body temperature, heart rate, or sevoflurane concentrations. Conclusions: Palonosetron may induce QTc prolongation during the early general anesthesia period with sevoflurane [ABSTRACT FROM AUTHOR]