The safety and efficacy of minimal-flow desflurane anesthesia during prolonged laparoscopic surgery / 대한마취과학회지

BACKGROUND: Minimal-flow anesthesia can meet the demands of a modern society that is more sensitive to environmental protection and economic burdens. This study compared the safety and efficacy of minimal-flow desflurane anesthesia with conventional high-flow desflurane anesthesia for prolonged laparoscopic surgery. METHODS: Forty-six male patients (ASA physical status II or III) undergoing laparoscopic urologic surgery for more than 6 hours were randomly divided into two groups: the high-flow (HF) group and the minimal-flow (MF) group. The HF group was continuously administered a fresh gas flow of 4 L/min. In the MF group, a fresh gas flow of 4 L/min was administered for the first 20 minutes and was thereafter lowered to 0.5 L/min. Inspiratory and expiratory desflurane concentrations, respiratory variables, and hemodynamic variables were continuously monitored during administration of anesthesia. Measurements of carboxyhemoglobin (COHb) concentration and arterial blood gas analysis were performed every 2 hours during anesthesia. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN) and creatinine were measured on the first and second day after the surgery. RESULTS: Demographic data and duration of anesthesia were not different between the two groups. Significant differences were not observed between the two groups in terms of hemodynamic variables, respiratory variables, and inspiratory and expiratory desflurane concentrations. Inspiratory O2 concentration was maintained lower in the MF group than in the HF group (43-53% vs. 53-59%; P < 0.05). Compared with the HF group, COHb concentrations was higher (P < 0.05), but not increased from the baseline value in the MF group. Serum AST, ALT, BUN, and creatinine were not significantly different between the two groups. CONCLUSIONS: In prolonged laparoscopic surgery, no significant differences were found in safety and efficacy between minimal-flow and high-flow desflurane anesthesia.

Procedural sedation with dexmedetomidine for pediatric endoscopic retrograde cholangiopancreatography guided stone retraction / 대한마취과학회지

No abstract available.

Estimation and simulation of kinetic-pharmacodynamic parameters of rocuronium by Bragg's dose-response-time model

BACKGROUND: The effect-time data involves some pharmacokinetic (PK) information. Bragg model could derive the information from pharmacodynamic (PD) data alone. After administering rocuronium, we collected tension data without these plasma concentration values. We determined kinetic-pharmacodynamic (K-PD) parameters, simulated the predictions of effect-time relation at different amount of dose, and validated the calculated infusion rates (IR) by comparing with IR directly measured. METHODS: Thirteen dexterous male patients were given rocuronium 300microg/kg during propofol-fentanyl anesthesia. Twitch tensions of the right adductor pollicis in response to supramaximal single twitch stimulation every 10 seconds were measured until muscle paralysis recovered by 70 +/- 10% of control. The above data were fitted to Bragg equation, using Tablecurve3D(R). The parameters, k1, k2, IR50, and gamma, were derived with either individual regression or population regression. The correlations between individual parameter and time, the simulation, and validation by infusing rocuronium 3.66microg/kg/min were examined. RESULTS: Based on population regression, IR50 was 3.70microg/kg/min, gamma was 4.51, k1 (keo) was 0.71/min, and k2 (k10) was 0.022/min. The longer the duration of rocuronium action was, the smaller the values of IR50 and k2 were (correlation coefficient: -0.92, -0.61, respectively). ED50 calculated (= IR50/k2) was 168microg/kg. The effects of rocuronium 3.66microg/kg/min were estimated (45% by direct measurement, 49% by population parameters, and 21% by individual parameters). CONCLUSIONS: The results of infusion rate validation suggests that population parameters may better be applicable than individual post hoc parameters to predicting the clinically relevant effect-time relations.