The optimal effect-site concentration of sufentanil for laryngeal mask insertion during induction with target-controlled propofol infusion at 4.0 μg/mL.
OBJECTIVE
The objective of this study is to determine the optimal effect-site concentration (Ce) of sufentanil for satisfactory insertion of laryngeal mask airway (LMA) when administered with a target-controlled infusion (TCI) of propofol at 4.0 μg/mL.


METHODS
A total of 25 adult patients scheduled for minor elective surgery were enrolled in this study. All patients received induction with a combination of propofol and sufentanil TCI. The TCI of sufentanil was started at a target Ce of 0.1 ng/mL. After equilibrium with the plasma concentration, the TCI of propofol was initiated, targeting a preset Ce of 4.0 μg/mL. After the loss of consciousness, LMA was inserted and assessed by an experienced Anesthesiologist. The Ce of sufentanil for the next patient was guided by modified Dixon's up-and-down method using 0.05 ng/mL as a step size. The Ce of sufentanil required for successful LMA insertion in 50% of adults (EC50) was determined by calculating the midpoint concentration of all independent pairs of patients after at least seven crossover points.


RESULTS
The optimal Ce (EC50) of sufentanil for LMA insertion during propofol induction using target Ce of 4 μg/mL was 0.16 ng/mL (95% confidence interval [CI] = 0.12-0.20). There was a significant reduction in propofol induced pain score P = 0.0275 and insignificant hemodynamic changes.


CONCLUSIONS
Ce of sufentanil required for successful LMA insertion in 50% of patients (EC50) using propofol target Ce of 4.0 μg/mL was 0.16 ng/mL (95% CI = 0.12-0.20) with a significant reduction in the propofol induced pain and hemodynamic stability.
Department of Anesthesiology, University of Dammam, King Fahad Hospital, Al-Khobar, Saudi Arabia.
Roshdi R
RR
Al-Metwalli
Laryngeal mask airway; propofol; sufentanil