Cigarette smoking, opioid consumption, and pain intensity after major surgery: An observational study

Background: Chronic exposure to nicotine may change pain perception and promote opioid intake. This study aimed to evaluate the putative effect of cigarette smoking on opioid requirements and pain intensity after surgery. Methods: Patients who underwent major surgery and received intravenous patient-controlled analgesia (IV-PCA) at a medical center between January 2020 and March 2022 were enrolled. Patients’ preoperative smoking status was assessed using a questionnaire by certified nurse anesthetists. The primary outcome was postoperative opioid consumption within three days after surgery. The secondary outcome was the mean daily maximum pain score, assessed using a self-report 11-point numeric rating scale, and the number of IV-PCA infusion requests within three postoperative days. Multivariable linear regression models were used to calculate the regression coefficient (beta) and 95% confidence interval (CI) for the association between smoking status and outcomes of interest. Results: A total of 1,162 consecutive patients were categorized into never smokers ( n =968), former smokers ( n =45), and current smokers ( n =149). Current smoking was significantly associated with greater postoperative opioid consumption (beta: 0.296; 95% CI: 0.068 – 0.523), higher pain scores (beta: 0.087; 95% CI: 0.009 – 0.166), and more infusion requests (beta: 0.391; 95% CI: 0.073 – 0.710) compared with never smokers. In a dose-dependent manner, smoking quantity (cigarette per day) was positively correlated with both intraoperative (Spearman's rho: 0.2207, p =0.0068) and postoperative opioid consumption (Spearman's rho: 0.1745, p =0.0333) among current smokers. Conclusion: Current cigarette smokers experienced higher acute pain, had more IV-PCA infusion requests, and consumed more opioids after surgery. Multimodal analgesia with non-opioid analgesics and opioid-sparing techniques, along with smoking cessation should be considered for this population.