Background: This study was to estimate the predicted effect-site concentration of propofol administered by a target-controlled infusion (TCI) for maintenance of anesthesia based on the bispectral (BIS) index as a measure of hypnosis in laparoscopic surgery. Method: One-hundred and sixty unpremedicated patients undergoing gynecologic laparoscopy were assigned randomly to receive one of the target effect-site concentrations of propofol 2.0, 2.5, 3.0, 3.5 and 4.0 g/ml during TCI with propofol and sufentanil. The dose–response relationship of propofol for the maintenance of adequate anesthesia based on BIS, movement and hemodynamic response was investigated using a fixed effect-site concentration of sufentanil (0.2 ng/ml). The BIS values, hemodynamic variables, time course during emergence and intraoperative awareness were also assessed. Results: The predicted effect-site propofol concentrations for adequate anesthesia at the skin incision in 50% (EC50) and 95% (EC95) of patients undergoing gynecologic laparoscopy were 2.2 and 3.7 g/ml, respectively. The predicted propofol EC50 and EC95 to maintain adequate anesthesia in these patients were 2.6 g/ml (95% CI 2.3–2.7 g/ml) and 3.6 g/ml (95% CI 3.3–4.0 g/ml), respectively. The BIS values, effect-site concentration of propofol, hemodynamic data and time course during emergence and post-operative adverse events were comparable in each group. There were no reports of intraoperative awareness in the post-anesthetic care unit. Conclusion: Based on the anesthetic depth assessed by the clinical signs and BIS monitoring, the predicted effect-site propofol concentrations for the maintenance of anesthesia in patients undergoing gynecologic laparoscopy were similar in those administered adequate anesthesia at the skin incision during TCI.
Department of Anesthesiology and Pain Medicine, School of Medicine, Konyang University Hospital, Daejeon, Korea 2:
Department of Anesthesiology and Pain Medicine, School of Medicine, Inha University Hospital, Incheon, Korea