Effect of Remifentanil on Acute and Chronic Postsurgical Pain in Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-analysis.

Objectives: Our purpose was to explore the effect of remifentanil on acute and chronic postsurgical pain after cardiac surgery.

Materials and methods: Randomized controlled trials were retrieved from electronic databases, such as PubMed, Cochrane Library, China National Knowledge Internet databases, Scopus, and Web of Science. A systematic review, meta-analysis, and trial sequential analysis (TSA) were performed. Basic information and outcomes were extracted from the included studies. The primary outcome was chronic postsurgical pain. Secondary outcomes were scores of postsurgical pain and morphine consumption within 24 hours after cardiac surgery. Risk of bias (ROB) assessment was based on the Cochrane ROB tool version 2. The overall quality of the evidence was rated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.

Results: Seven studies consisting of 658 patients were enrolled in the meta-analysis. A single study had a high ROB and 2 studies had a moderate ROB. The incidence of chronic postsurgical pain (4 studies [415 patients]; risk ratio: 1.02 [95% CI: 0.53 to 1.95]; P = 0.95; I2 = 59%; TSA-adjusted CI: 0.78 to 1.20) and the postsurgical pain score (2 studies [196 patients]; mean difference: 0.09 [95% CI: -0.36 to 0.55]; P = 0.69; I2 = 0%; TSA-adjusted CI: -0.36 to 0.55) were not statistically different between the 2 groups. However, morphine consumption (6 studies [569 patients]; mean difference: 6.94 [95% CI: 3.65 to 10.22]; P < 0.01; I2 = 0%; TSA-adjusted CI: 0.00 to 0.49) was higher in the remifentanil group than in the control group.

Conclusion: There was not enough evidence to prove that remifentanil can increase the incidence of chronic postsurgical pain after cardiac surgery, but interestingly, the results tended to support a trend toward increased complications in the intervention group. However, there was moderate certainty evidence that the use of remifentanil increases the consumption of morphine for analgesia, and more direct comparison trials are needed to inform clinical decision-making with greater confidence.