Remifentanil Versus Fentanyl in Critically Ill Patients Requiring Mechanical Ventilation: A Single-Center Retrospective Cohort Study

Background Remifentanil, known for its ultra-short-acting properties and organ-independent metabolism, offers benefits over traditional opioids. Although approved for intensive care unit (ICU) use in Japan since 2022, its comparative effects against fentanyl in mechanically ventilated critically ill patients remain unclear. This study evaluated the effects of remifentanil versus fentanyl in this population. Methods This retrospective, single-center observational study included patients in ICUs requiring mechanical ventilation between April 2021 and May 2024 (excluding patients in postoperative status). Propensity score matching was performed to adjust for baseline differences. The primary outcome was mechanical ventilation duration. Secondary outcomes included delirium incidence and drug-associated costs. Statistical analyses were conducted using Mann-Whitney U and chi-square tests. Results Of 198 eligible patients, 31 were analyzed in each group following matching. The median (interquartile range) ventilation duration was 107.5 (45.6-196.8) and 124.1 (93.8-324.0) hours for remifentanil and fentanyl, respectively (median difference: -16.6 hours; 95% confidence interval: -147.0-26.2; P = 0.15), indicating statistical non-significance but a wide confidence interval that suggests the potential for a clinically meaningful difference. Delirium incidence was lower in the remifentanil group (77.4% vs. 96.4%; χ²(1) = 4.99, P = 0.03, φ = 0.29). Although daily analgesic costs were significantly higher for remifentanil than fentanyl ($29.5 vs. $13.9; P < 0.01), total sedation-analgesia costs were similar between the groups ($45.3 vs. $26.2; P = 0.13). Conclusion Although remifentanil did not significantly reduce ventilation duration compared to fentanyl, it was associated with a significantly lower delirium incidence, suggesting potential advantages in sedation.