Requirements for target-controlled infusion of propofol to insert the laryngeal mask airway

The success rate for insertion of the laryngeal mask airway was assessed in 60 patients using a target-controlled infusion of propofol. Eleven of 15 patients who received a target propofol concentration of 5 micrograms.ml-1 had the laryngeal mask inserted successfully within 3 min of induction of anaesthesia. Fourteen of 15 patients who received 6 micrograms.ml-1 had successful insertion within 3 min and all 15 patients who received 7 micrograms.ml-1 had successful insertion within 3 min. Patients who received 8 micrograms.ml-1 had successful insertion within 90s of induction of anaesthesia. The increased success rate of LMA insertion with the higher target propofol concentrations was achieved without major haemodynamic effects in this group of fit patients. However, adverse cardiovascular effects may occur with these doses in elderly or unfit patients. It is important in individual patients to titrate the target propofol concentration to achieve the required clinical endpoint.