Effect of opioid-free anaesthesia on post-operative period in cardiac surgery: a retrospective matched case-control study

BACKGROUND: No study has been conducted to demonstrate the feasibility of an opioid-free anesthesia (OFA) protocol in cardiac surgery to improve patient care. The aim of the present study was to evaluate the effect of OFA on post-operative morphine consumption and the post-operative course. METHODS: After retrospectively registering to clinicaltrial.gov (NCT03816592), we performed a retrospective matched cohort study (1:1) on cardiac surgery patients with cardiopulmonary bypass between 2018 and 2019. Patients were divided into two groups: OFA (lidocaine, dexamethasone and ketamine) or opioid anaesthesia (OA) (sufentanil). The main outcome was the total postoperative morphine consumption in the 48 h after surgery. Secondary outcomes were rescue analgesic use, a major adverse event composite endpoint, and ICU and hospital length of stay (LOS). RESULTS: One hundred ten patients were matched (OFA: n = 55; OA: n = 55). On inclusion, demographic and surgical data for the OFA and OA groups were comparable. The total morphine consumption was higher in the OA group than in the OFA group (15 (6–34) vs 5 mg (2–18), p = 0.001). The pain score during the first 48 post-operative hours did not differ between the two groups. Creatinine values did not differ on the first post-operative day (80 (IQR: 66–115) vs 77 mmol/l (IQR: 69–95), p = 0.284). Incidence of the composite endpoint was lower in the OFA group (25 patients (43%) vs 38 patients (68%), p = 0.021). The time to extubation and the ICU stays were shorter in the OFA group (3 (1–5) vs 5 (3–6) hours, p = 0.001 and 2 (1–3) vs 3 (2–5) days, p = 0.037). CONCLUSION: The use of OFA was associated with lower morphine consumption. OFA might be associated with shorter intubation time and ICU stays. Further randomized studies are needed to confirm these results. TRIAL REGISTRATION: This study was retrospectively registered to ct2 (identifier: NCT03816592) on January 25, 2019.