Does a hypnosis session reduce the required propofol dose during closed-loop anaesthesia induction?: A randomised controlled trial

Background Hypnosis has a positive effect on peri-operative anxiety and pain. Objective The objective of this study was to assess the impact of a formal deep hypnosis session on the consumption of propofol for anaesthetic induction using automated administration of propofol guided by the bispectral index (BIS) in a closed loop. Design A 1 : 1 randomised, usual-care-controlled, single-centre trial. Setting Tertiary care centre in France from April 2014 to December 2015. Patients Female adult patients scheduled for outpatient gynaecological surgery under general anaesthesia. Intervention Before surgery, patients were randomised to receive either a deep hypnosis session or routine care. Anaesthetic induction was performed automatically by propofol without opioids and was assisted by the BIS in a closed loop. Main outcome measures The primary endpoint was the propofol dose required for anaesthesia induction, defined as a BIS less than 60 for at least 30 s. Results Data for 31 patients in the hypnosis group and 35 in the control group were analysed. There was no evidence of a difference in the mean required propofol dose for anaesthetic induction between the hypnosis and the control groups (2.06 mg kg (95% confidence interval [1.68 to 2.43]) versus 1.79 mg kg (95% CI [1.54 to 2.03]), P = 0.25, respectively). Conclusion The current study, which was designed to determine the effect of a deep hypnosis session on anaesthesia induction using an automated tool for propofol administration, failed to detect a difference in the required dose of propofol. Trial registration ClinicalTrials.gov, NCT02249364.