Rapid injection of propofol reduces vascular pain and facilitates Laryngeal Mask Airway insertion

Study ObjectiveTo compare the clinical efficacy of a rapid injection of propofol in regard to pain and ability to facilitate Laryngeal Mask Airway (LMA) insertion.DesignRandomized, single-blinded, placebo-controlled study.SettingUniversity hospital.Patients120 ASA physical status 1 and 2 patients undergoing elective orthopedic surgeries.InterventionsPatients were randomly allocated to one of 4 groups. Group A patients were pretreated with normal saline followed by propofol 2.0 mg/kg at 3.3 mg/sec. Group B patients were pretreated with lidocaine 0.5 mg/kg followed by propofol 2.0 mg/kg at 3.3 mg/sec. In Group C, patients were pretreated with lidocaine 1.0 mg/kg followed by propofol 2.0 mg/kg at 3.3 mg/sec. In Group D, patients were pretreated with normal saline followed by propofol 2.0 mg/kg at 50 mg/sec.MeasurementsPain on injection was measured using a 4-point scale. Scale and success rate of smooth LMA insertion also were recorded.Main ResultsRapid injection was less painful than after pretreatment with lidocaine 0.5 mg/kg, but was similar to slow injection after pretreatment with lidocaine 1.0 mg/kg. Rapid injection facilitated LMA insertion, unlike slow injection with lidocaine 0.5 mg/kg pretreatment, and was similarly successful to slow injection after pretreatment with lidocaine 1.0 mg/kg.ConclusionsThe rapid administration of propofol reduces pain and facilitates LMA insertion versus slow administration of propofol.