Spontaneous movement after injection of propofol

Spontaneous movement following injection of propofol at induction was studied in 303 patients. Two hundred patients were Caucasians and 103 were Asians. In a pilot study carried out prior to the main study, 26% of the Asians moved at induction as compared with 6% of the Caucasians. The patients were studied in relation to a number of variables; age, sex, weight, height, race, smoker/non smoker, vegetarian/non vegetarian, alcohol consumption, premedication, use of fentanyl at induction and dose of propofol. When race was included as the sole variable there was a marginal but not significant difference between the two groups in terms of movement (p = 0.06). However, when the other recorded variables were taken into account, race was not included as a predictor of whether or not the patient moved. The best model for predicting whether the patients moved or not combines the variables weight and dose of propofol. Patients were more likely to move if they were lighter and the dose of propofol used at induction was higher.