Patient-maintained versus anaesthetist-controlled propofol sedation during elective primary lower limb arthroplasty performed under spinal anaesthesia: a randomised controlled trial

Background: Patient-maintained propofol sedation (PMPS) allows patients to titrate their own target-controlled infusion (TCI) delivery of propofol sedation using a handheld button. The aim of this randomised controlled trial was to compare PMPS with anaesthetist-controlled propofol TCI sedation (ACPS) in patients undergoing elective primary lower limb arthroplasty surgery under spinal anaesthesia. Methods: In this single-centre, open-label, investigator-led study, adult patients were randomly assigned to either PMPS or ACPS during their surgery. Both sedation regimes used Schnider effect-site TCI modelling. The primary outcome measure was infusion rate adjusted for weight (expressed as mg kg-1 hr-1). Secondary outcomes measures included depth of sedation, occurrence of sedation-related adverse events and time to medical readiness for discharge from the post-anaesthesia care unit (PACU). Results: Eighty patients (48 females) were randomised. Patients using PMPS used 39.3% less propofol during the sedation period compared to patients in group ACPS (1.56 (0.57) vs 2.56 (1.33) mg kg-1 hr-1; p < 0.001), experienced fewer discrete episodes of deep sedation (0 vs 6, p = 0.0256), fewer airway/breathing adverse events (odds ratio (95% CI) 2.94 (1.31 –6.64); p = 0.009) and were ready for discharge from PACU more quickly (8.94 (5.5) vs 13.51 (7.2) minutes; p = 0.0027). Conclusion: PMPS during lower limb arthroplasty under spinal anaesthesia results in reduced drug exposure and fewer episodes of sedation related adverse events compared to ACPS. To facilitate further investigation of this procedural sedation technique, PMPS-capable TCI infusion devices should be submitted for regulatory approval for clinical use