Randomised, double-blinded, placebo-controlled trial to investigate the role of laparoscopic transversus abdominis plane block in gastric bypass surgery: a study protocol.

Introduction: Evaluating the efficacy of a laparoscopically guided, surgical transversus abdominis plane (TAP) and rectus sheath (RS) block in reducing analgesic consumption while improving functional outcomes in patients undergoing laparoscopic bariatric surgery.

Methods: 150 patients Living with obesity undergoing elective laparoscopic Roux-En-Y gastric bypass for obesity will be recruited to this double-blinded, placebo-controlled randomised controlled trial from a Bariatric Centre of Excellence over a period of 6 months. Patients will be electronically randomised on a 1:1 basis to either an intervention or placebo group. Those on the intervention arm will receive a total of 60 mL 0.25% ropivacaine, divided into four injections: two for TAP and two for RS block under laparoscopic visualisation. The placebo arm will receive normal saline in the same manner. A standardised surgical and anaesthetic protocol will be followed, with care in adherence to the Enhanced Recovery after Bariatric Surgery guidelines.

Analysis: Demographic information and relevant medical history will be collected from the 150 patients enrolled in the study. Our primary efficacy endpoint is cumulative postoperative narcotic use. Secondary outcomes are peak expiratory flow, postoperative pain score and the 6 min walk test. Quality of recovery (QoR) will be assessed using a validated questionnaire (QoR-40). Statistical analysis will be conducted to assess differences within and between the two groups. The repeated measures will be analysed by a mixed modelling approach and results reported through publication.

Ethics And Dissemination: Ethics approval was obtained (20170749-01H) through our institutional research ethics board (Ottawa Health Science Network Research Ethics Board) and the study results, regardless of the outcome, will be reported in a manuscript submitted for a medical/surgical journal.

Trial Registration Number: Pre-results NCT03367728.