Introduction: Ketamine offers hemodynamic stability, bronchodilation, and opioid-sparing effects, yet its overall impact on ICU outcomes remains uncertain. We hypothesised that intravenous ketamine infusions would reduce mechanical ventilation (MV) duration, shorten ICU length of stay (LOS), and decrease delirium incidence compared to standard analgosedation. Methods: MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov were systematically searched through June 2025 for randomized or prospective controlled adult ICU trials comparing intravenous ketamine/esketamine with usual care. Pooled analyses were performed using the meta package in R 4.5.1. Mean differences (MD) were calculated for MV duration and ICU LOS, and risk ratios (RR) for delirium using Hartung-Knapp random-effects models. Heterogeneity was assessed using the I2 statistic. Robustness was evaluated via leave-one-out sensitivity analysis. Results: Six trials (n = 903) met inclusion criteria. All six reported MV duration, showing a modest non-significant reduction with ketamine (MD -0.30 days; 95% CI -1.53 to 0.92; p = 0.55; I2 = 88%). Sensitivity analysis showed no single study substantially influenced the estimate. ICU LOS, reported in five studies (n = 797), was significantly shorter with ketamine by nearly one day (MD -0.86 days; 95% CI -1.51 to -0.22; p = 0.02; I2 = 0%). Delirium was reported in two trials (n = 544) and occurred in 22.9 % of ketamine-treated patients versus 41.4 % of controls, yielding a 45 % relative risk reduction (RR = 0.55, 95 % CI 0.43 to 0.72; I2 = 0 %) and an absolute risk difference of –18.5 % (number-needed-to-treat ≈ 6). Conclusions: While adjunctive ketamine did not significantly reduce mechanical ventilation time, it consistently decreased ICU LOS and notably reduced delirium incidence without inter-study variability. These findings support ketamine’s integration into multimodal ICU sedation and underscore the need for large, pragmatic trials to refine its clinical use.
Patel et al. (Sun,) studied this question.