The Postoperative Lidocaine and Ketamine Effects on Morphine Requirement in Bariatric Surgery

Effective postoperative pain management in patients with obesity undergoing metabolic bariatric surgery is challenging due to the adverse effects associated with opioid use. Multimodal analgesic approaches during the intraoperative period have been shown to effectively reduce postoperative opioid consumption. This study evaluated the impact of prolonged postoperative lidocaine and ketamine infusion for 90 min on postoperative morphine consumption as a complementary multimodal analgesic approach.

This retrospective cohort study included 64 patients who underwent elective sleeve gastrectomy and Roux-en-Y gastric bypass (RYGB). Thirty-two patients who received lidocaine and ketamine infusions postoperatively (group A) were compared with 32 patients who received standard postoperative analgesia (group B). The primary outcome measured was total morphine consumption within the first 48 h post-surgery. Pain was assessed using the visual analog scale (VAS) at 1, 2, 4, 24, and 48 h post-surgery.

Mean cumulative morphine consumption at 48 h was 0.82 ± 1.55 mg in group A versus 2.03 ± 2.61 mg in group B (p = 0.0696). In total, 62.5% of patients did not require morphine during the first 48 postoperative hours. VAS scores were significantly lower in group A at four postoperative hours (1.03 ± 1.36) compared to group B (2.16 ± 1.65) (p = 0.0024).

Postoperative morphine consumption and pain scores were low in the current multimodal analgesic approach. Prolonging lidocaine and ketamine infusion for 90 min postoperatively was not justified based on the current results.