Randomised Controlled Trial of Patient Controlled Sedation for Colonoscopy: Entonox Versus Patient Maintained Target Controlled Propofol

Abstract

Introduction: Intravenous sedation for colonoscopy is associated with cardio-respiratory complications and we have previously shown that Entonox is superior to intravenous sedation. We aimed to compare patient controlled Entonox inhalation with patient-maintained target-controlled Propofol infusion for colonoscopy in terms of analgesic efficacy, psychomotor recovery, patient and endoscopist satisfaction. Methods: All patients undergoing elective colonoscopy were included. Ethics committee approval was obtained and patients were randomized to receive either Entonox or target-controlled propofol. Patients in entonox group inhaled gas for 60 seconds before procedure and then as required. Patients in propofol group were administered drug with target value of 1 μg/ml loading dose and then allowed to sedate themselves using handset. Patients completed anxiety score, baseline letter-cancellation test and pain score on 100 mm-visual analogue scale(VAS) before procedure and then repeated the same immediately after procedure and at discharge. Patients completed satisfaction survey at discharge and 24-hours post-procedure. Secondary end-points measured were completion rates, nurse and endoscopist satisfaction and complication rates. An anaesthetist was present throughout the procedure. Results 100 patients were randomised to receive Entonox (n = 50) or Propofol (n = 50). The median dose of propofol was 174 mg and the median time required to reach target concentration was 3 minutes. There was no difference in two groups in terms of pain recorded (Entonox group mean score 20 versus 15) with similar pre-procedure anxiety scores. There was no difference between two groups in terms of completion rates, time to caecum, total colonoscopy time and endoscopistpatient and nurse satisfaction. The depth of sedation was higher in propofol group (median 3/5 as compared to 1/5 in entonox group), with more patients needing assistance for change of position during procedure as compared to Entonox group (6 versus none; p < 0.05). Psychomotor recovery and discharge was faster in entonox group, though differences were not statistically significant. Conclusion: Patient controlled sedation using target-controlled Propofol provides greater depth of sedation as compared to entonox; both techniques are safe and effective for colonoscopy, providing good patient satisfaction and facilitating early discharge. We believe that Entonox should be used in all patients undergoing colonoscopy but with patient controlled propofol used instead of midazolam/analgesia for those cases where entonox is unsuitable.