Male patients require higher optimal effect-site concentrations of propofol during i-gel insertion with dexmedetomidine 0.5 μg/kg

Abstract

BackgroundThe pharmacokinetics and pharmacodynamics of an anesthetic drug may be influenced by gender. The purpose of this study was to compare effect-site half maximal effective concentrations (EC50) of propofol in male and female patients during i-gel insertion with dexmedetomidine 0.5 μg/kg without muscle relaxants.MethodsForty patients, aged 20–46 years of ASA physical status I or II, were allocated to one of two groups by gender (20 patients per group). After the infusion of dexmedetomidine 0.5 μg/kg over 2 min, anesthesia was induced with a pre-determined effect-site concentration of propofol by target controlled infusion. Effect-site EC50 values of propofol for successful i-gel insertion were determined using the modified Dixon’s up-and-down method.ResultsMean effect-site EC50 ± SD of propofol for successful i-gel insertion was significantly higher for men than women (5.46 ± 0.26 μg/ml vs. 3.82 ± 0.34 μg/ml, p < 0.01). The EC50 of propofol in men was approximately 40 % higher than in women. Using isotonic regression with a bootstrapping approach, the estimated EC50 (95 % confidence interval) of propofol was also higher in men [5.32 (4.45–6.20) μg/ml vs. 3.75 (3.05–4.43) μg/ml]. The estimated EC95 (95 % confidence interval) of propofol in men and women were 5.93 (4.72–6.88) μg/ml and 4.52 (3.02–5.70) μg/ml, respectively.ConclusionsDuring i-gel insertion with dexmedetomidine 0.5 μg/kg without muscle relaxant, male patients had higher effect-site EC50 for propofol using Schnider’s model. Based on the results of this study, patient gender should be considered when determining the optimal dose of propofol during supraglottic airway insertion.Trial registrationClinicalTrials.gov identifier: NCT02268656. Registered August 26, 2014.

The optimum sevoflurane concentration for supraglottic airway device Blockbuster™ insertion with spontaneous breathing in obese patients: a prospective observational study

“…The sample size of this study was based on the fact that a minimum of eight independent pairs of participants showing a crossover point from a ‘movement’ response to a ‘no-movement’ response required for the statistical analysis [ 24 , 25 ]. In similar studies in the field of airway device insertion, the number of crossover points varies from six to eight, with six crossover points being most common [ 23 , 26 , 27 ]. For this study, eight crossovers were considered sufficient to determine the ED 50 of sevoflurane required to insert the suppraglottic airway device Blockbuster™.…”

Infant spinal anesthesia: Do girls need a larger dose of local anesthetic?

“…A pharmacokinetic model of remifentanil demonstrated an effect of age and lean body mass but no influence of sex on any pharmacokinetic or pharmacodynamic parameter . In contrast, males are more sensitive than females to propofol with a 30%‐40% reduction in dose required to achieve similar recovery times . The overall effect is that sex adversely impacts the overall quality of recovery from anesthesia …”

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