Reduction of propofol infusion pain using target controlled infusion of remifentanil

BACKGROUND: Propofol has a high incidence of infusion pain. We hypothesized that propofol infusion pain might be prevented by infusing remifentanil before starting the propofol infusion in a clinical setting where target controlled infusions (TCI) of both drugs were used. We compared the efficacy of remifentanil TCI administered 90 seconds before propofol TCI with remifentanil TCI and propofol TCI given immediately after a 40 mg lidocaine bolus in prevention of propofol infusion pain. METHODS: One hundred sixty five ASA 1 or 2 patients scheduled for elective surgery under general anesthesia were classified in three groups. Group C: propofol TCI and remifentanil TCI was started at the same time (n = 55), group L: lidocaine 40 mg injection immediately prior to propofol TCI and remifentanil TCI (n = 55), group R: remifentanil TCI was started 90 seconds before propofol TCI (n = 55). Pain severity of propofol infusion was evaluated using a four-point scale (none, mild, moderate, severe). RESULTS: The incidence of pain in group R and group L was significantly lower than in group C. There was no significant difference between group R and group L. But the incidence of moderate and severe pain in group R was significantly lower than in group L (P < 0.05). CONCLUSIONS: Remifentanil TCI 90 seconds before propofol TCI reduces propofol infusion pain than propofol TCI and remifentanil TCI started at the same time. This protocol is considered to be more effective in alleviating moderate and severe pain than lidocaine.

The optimal dosage of alfentanil pretreatment for prevention of myoclonus after injection of etomidate / 대한마취과학회지

BACKGROUND: Myoclonus is a common problem during induction of general anesthesia with etomidate. We investigated the optimal dosage of alfentanil pretreatment for prevention of myoclonus after injection of etomidate. METHODS: In a double blinded fashion, 76 patients scheduled for outpatient elective surgery were randomized into 4 groups according to pretreatment drug: alfentanil 2.5microgram/kg, alfentanil 5microgram/kg, alfentanil 10microgram/kg, or normal saline. The pretreatment was followed by etomidate 0.3 mg/kg IV. Laryngeal mask airway (LMA) was inserted at 5 minutes after the induction. The patients were observed for any myoclonic movement. Onset time, duration and intensity of myoclonus, side effects of alfentanil, mean arterial pressure and heart rate were measured during the study period. RESULTS: There were significant differences in the incidence and intensity of myoclonus. An injection of 5, and 10microgram/kg alfentanil before etomidate prevented increase of mean arterial pressure and heart rate after LMA insertion. But injection of 10 microgram/kg alfentanil before etomidate appeared generalized muscle rigidity, bradycardia and hypotension. CONCLUSIONS: An injection of 2.5, 5, and 10microgram/kg alfentanil before etomidate decreases the incidence and intensity of myoclonus. But injection of 10microgram/kg alfentanil before etomidate appeared side effects. Therefore the optimal dosage of alfentanil pretreatment for prevention of myoclonus after injection of etomidate is 5microgram/kg.