Role of vitamin C in multimodal analgesia for sleeve gastrectomy: a prospective randomized controlled trial

Background & Objective: The laparoscopic sleeve gastrectomy is a popular intervention in morbidly obese patient. Postoperative pain relief is a major challenging issue in this procedure with known adverse effects on the respiratory excursion and the ability to cough by the patient. Various analgesic protocols have been tries to conquer this pain. Vitamin C is a micronutrient, water soluble vitamin with antioxidant and antinociceptive actions. We assessed the effect of vitamin C when used as a component of the multimodal analgesic technique in this cohort of the patients.Methodology: After obtaining the ethical committee approval and trial registration, 50 patients scheduled for laparoscopic sleeve gastrectomy were enrolled in this study. The patients were randomly divided into two equal groups according to the study protocol. Group C received vitamin C 500 mg every 8 h for 5 days perioperatively, while Group N received placebo in the same fashion. The surgery was performed under routine general anesthesia. We monitored hemodynamic, VAS, rescue analgesia profile, and gastrointestinal side effects in the immediately after operation, and then at 1, 2, 4, 8, 12, and at 24 h postoperatively. The postoperative morphine consumption was noted as a primary objective of the study. Independent sample T test, Mann-Whitney test, chi square test or Kruskal Wallis test were utilized to detect statistical differences between the studied groups. P < 0.05 was considered significant.Results: Postoperative morphine consumption was lower in Group C than in Group N (16.36 +/- 2.37 vs. 20 +/- 4.13 mg, P = 0.001). The frequency of morphine was significantly lower in Group C than in Group N (P = 0.009). VAS was lower in Group C than Group N at 4, 8, and 12 h postoperatively (P = 0.02, 0.001, 0.001), while other parameters where comparable. Abbreviation: CBC: complete blood count; IRB: Institutional Research Board; LFTs: liver function tests; LSG: laparoscopic sleeve gastrectomy; MABP: mean arterial blood pressure; NMDA: N-methyl D-aspartate; OSAS: obstructive sleep apnea syndrome; PACTR: Pan African Clinical Trial Registry; PEEP: positive end expiratory pressure.; PFT: pulmonary function tests; RFTs: renal function tests; TFTs: thyroid function test; TOF: train of four; VAS: visual analogue score. Preregistration: Institutional Research Board, Mansoura Faculty of Medicine (IRB # R.20.02.738, Feb 15-2020). Pan African clinical trial registry (PACTR-202003565796463, date of registration: March 02-2020). Conclusion: Vitamin C via its antioxidant, antinociceptive properties and NMDA-receptor antagonist action can be used as a part of multimodal analgesic techniques. Vitamin C acts as co-analgesic, improves postoperative pain profile, and reduces the needs for other analgesic modalities.