Propofol concentration requirement for laryngeal mask airway insertion was highest with the ProSeal, next highest with the Fastrach, and lowest with the Classic type, with target-controlled infusion.

STUDY
OBJECTIVE: To determine propofol concentration of plasma 50% (Cp50, concentration at which there is a 50% chance that patients show no movement in response) for the Classic-, Fastrach-, and ProSeal-type laryngeal mask airway (LMA) insertion using target-controlled infusion (TCI) technique.
DESIGN: Prospective, randomized, comparative study.
SETTING: University-affiliated hospital. PATIENTS: Sixty American Society of Anesthesiologists physical status I and II women scheduled for minor gynecologic operations.
INTERVENTIONS: Propofol TCI (Diprifusor pharmacokinetic model) was started at target concentration using an anesthesia pump. After reaching target effect-site concentration of propofol, 1 of the 3 types of LMA was inserted. We recorded patient responses to LMA insertion as "movement" or "no movement." Test propofol concentrations started from a dosage of 4 microg/mL. Concentrations were then predetermined by a modified Dixon's up-and-down method with 0.4 microg/mL step size. MEASUREMENTS: Patient response to LMA insertion was classified as either of "no movement" or "movement." The midpoint was defined as the average concentration value of crossover (movement/no movement) response. The Cp50 value was defined as the average of the crossover midpoints in each group, and it was estimated from calculating the midpoints. MAIN
RESULTS: Cp50 of the Classic, Fastrach, and ProSeal LMA insertion were 3.2+/-0.34, 4.0+/-0.22, and 4.9+/-0.20 microg/mL (mean+/-SD), respectively.
CONCLUSION: Required propofol TCI concentrations for LMA insertion were significantly highest for the ProSeal, second highest for the Fastrach, and lowest for the Classic LMA.

RCT Entities:   Population Interventions Outcomes