The supraglottic airway device (SAD) can be used for airway management of spontaneous breathing patients, and propofol is commonly applied for the SAD placement. This study was designed to assess the effect of gender on median target effect-site concentration (Ce₅₀) of propofol for I-gel placement when combined with dexmedetomidine.

19 males and 18 females, aged 18 to 59 and undergoing elective surgery, were enrolled. After intravenous infusion of dexmedetomidine 1.0μg/kg over 10min followed by continuous infusion of 0.4μg/kg/h, target-controlled infusion of propofol under Marsh model was started and the initial Ce of propofol was set at 4.79μg/mL and 4.35μg/mL in the male and female patients, respectively. The I-gel was inserted when the Ce of propofol reached the pre-set concentration and bispectral index value was less than 60. The Ce of propofol required for I-gel placement was determined by the Dixon up-and-down method.

The Ce₅₀ (95% confidence interval) of propofol required for I-gel placement were 4.082μg/mL (3.798–4.332μg/mL) and 3.509μg/mL (3.266–3.749μg/mL) in male and female patients, respectively, with a significantly higher Ce₅₀ in males.

When combined with dexmedetomidine, males require a higher Ce₅₀ of propofol for I-gel placement compared to females.