Effects of opioid-free anesthesia on postoperative morphine consumption after bariatric surgery.

STUDY OBJECTIVES: The objective of this study was to determine whether postoperative morphine requirement in obese patients undergoing laparoscopic bariatric surgery was reduced by opioid-free anesthesia (OFA), as compared to an anesthetic strategy using opioids (opioid balanced anesthesia (OBA)) and to investigate the differences that may exist between the use of clonidine and dexmedetomidine in the context of OFA. DESIGN: Retrospective cohort study. SETTING: Academic medical center in Lyon, France. PATIENTS: 257 patients who underwent laparoscopic bariatric surgery between March 2017 and March 2019. 77 patients were included in the OBA group and 180 in the OFA group. The OFA group was subdivided in two: 90 patients received OFA with clonidine (OFAC) and 90 received OFA with dexmedetomidine (OFAD). MEASUREMENTS: Proportion of patients who did not receive morphine during the first 24 postoperative hours. MAIN RESULTS: During the first 24 postoperative hours, the proportion of patients who did not require morphine was significantly higher in the OFA (87%) than in the OBA (52%) group (OR: 6.31; 95% CI [3.38; 11.80], P < 0.001). This difference remained significant after adjustment for age, body mass index, sex, type and duration of surgery (OR: 7.99; 95% CI [4.05; 16.48], P < 0.001). A greater proportion of patients in the OFAD (93%) than in the OFAC group (81%, P = 0.026) did not receive morphine during the same period. CONCLUSIONS: OFA is associated with a lower morphine requirement than with OBA during the first 24 h after bariatric surgery. In addition, OFAD seems to be more effective than OFAC in order to reduce morphine consumption.