Infusion of propofol ('Diprivan') as sedative technique for colonoscopies

Sixty male and female patients, scheduled for colonoscopy were premedicated with glycopyrrolate 0.4 mg intramuscularly. Anaesthesia was induced with 2 mg/kg propofol ('Diprivan') and maintained with a continuous infusion of propofol at a rate of 3, 6 or 9 mg/kg/h randomly allocated. Patients lost consciousness within 60.6 +/- 18.7 (s.d.) s. Preservation of the hypnotic effect was infusion-rate dependent as 15, 40 and 85% of the patients were unconscious on infusion rates of 3, 6 or 9 mg/kg/h propofol, respectively. A high degree of sedation was observed in the remaining patients with an incidence of 40, 35 and 0% in the different series. Sedation was light in the remainder of the patients. To increase the acceptability of the procedure, a supplemental bolus of propofol and/or an increase in the infusion rate were required in 40, 15 and 10% of the 3, 6 and 9 mg/kg/h infusion rate groups, respectively. The incidence of amnesia was similar in all three groups (80, 90 and 95%, respectively). Recovery was significantly longer with increasing infusion rate, but remained rapid. The longest time was 7.3 +/- 4.0 min to open eyes on command and 10.6 +/- 4.6 min to answer correctly. The most important side effects were pain on injection (50%) and some restlessness during maintenance (25%). Blood pressure decreased, but heart rate was unaffected. Patients breathed room-air spontaneously. Respiratory rate slowed after induction then increased rapidly above baseline values. The incidence of apnoea was 48% with a mean duration of 51 +/- 22s (s.d.). The technique was evaluated as good or adequate in 95% of the cases. We suggest than an analgesic premedication followed by an average of 6 mg/kg/h propofol by infusion might be a simple and convenient method of achieving good conditions for colonoscopy.