Adjunctive ketamine safe, effective for sedation in ICU

Sedation with adjunctive ketamine does not increase the percentage of Richmond Agitation-Sedation Scale (RASS) scores at goal relative to nonketamine sedatives (NKS), reveals a study.

Moreover, ketamine results in reductions in norepinephrine requirements, days of intermittent benzodiazepine administration, and number of patients receiving continuous infusion fentanyl.

“Continuous infusion ketamine appears safe and effective for sedation in the medical intensive care unit (MICU),” the investigators said.

A total of 172 patients who received continuous infusion ketamine (n=86) or NKS (n=86), including dexmedetomidine, fentanyl, midazolam, or propofol, admitted to the MICU between 2013 and 2018 were recruited in this single-centre, retrospective cohort study.

The percentage of RASS scores at goal in patients receiving ketamine as adjunct to NKS compared to those on NKS alone was the primary endpoint.

Baseline characteristics were similar between the two cohorts, except for antipsychotic use, which was higher in the ketamine group (p=0.008). No between-group difference was observed in the primary endpoint (78.7 percent vs 81.4 percent; p=0.29).

Fewer patients in the ketamine group received continuous infusion fentanyl (76.7 percent vs 94.2 percent; p=0.002). In addition, those on adjunctive ketamine required fewer days of intermittent benzodiazepines (0–1 vs 1–2 days; p<0.0001) and less norepinephrine (median 6.32 vs 11.7 mg; p=0.03).

No between-group difference was noted in receipt of new antipsychotics or occurrence of arrhythmias.

“Ketamine, an N-methyl-d-aspartate receptor antagonist with sedative and analgesic properties, is becoming more popular as an adjunctive sedative in the critically ill patients,” the investigators said.