We performed a systematic review with meta-analysis to examine the relationship between sedation including a continuous IV opioid infusion and duration of mechanical ventilation (MV) and relevant secondary outcomes in MV critically ill adults.

We searched MEDLINE, EMBASE, and Cochrane CENTRAL database up to March 2025. We included randomized controlled trials in MV critically ill adults comparing use of sedation including a continuous IV opioid versus sedation without. We assessed MV duration, pain, delirium and coma occurrence, ICU/hospital length of stay (LOS) and 28-day mortality. Study risk of bias was evaluated (PROSPERO: CRD42024498555). We pooled data using a Restricted Maximum Likelihood Estimation random-effects model and followed PRISMA guidelines.

Eight studies (n = 803 patients) published between 2006 and 2021 were included. Sedation including a continuous IV opioid (vs. sedation without) may increase MV duration (3 studies, 425 patients, mean difference (MD) = 3.63 hours, 95% confidence interval (CI) 2.27 to 4.99, very low certainty), reduce pain (2 studies, VAS score at 24 hours MD = −0.44 mm, 95% CI − 0.82 to −0.07, low certainty), reduce delirium (3 studies, odds ratio (OR) = 0.28, 95% CI 0.16 to 0.47, very low certainty) and reduce mortality (3 studies, OR = 0.41, 95% CI 0.21 to 0.80, very low certainty). Sedation including a continuous IV opioid does not increase coma or reduce ICU/ hospital LOS. Risk of bias was critical for most studies.

The effect of sedation including a continuous IV opioid on MV duration, pain delirium, coma, mortality and LOS remain uncertain. The role for continuous IV opioids as a part of ICU sedation regimens requires additional evaluation.