Ketamine for Primary Analgosedation in Critically Ill Surgery and Trauma Patients Requiring Mechanical Ventilation.

OBJECTIVES: Evaluate effectiveness and safety outcomes associated with the use of ketamine for primary analgosedation in the surgical/trauma ICU setting.

DESIGN: Retrospective cohort study.

SETTING: Academic medical center in Minnesota.

PATIENTS: Patients admitted to the surgical ICU between 2015 and 2019 requiring mechanical ventilation and meeting one of three definitions for ketamine primary analgosedation were included: 1) no concomitant opioid infusion, 2) ketamine monotherapy for greater than or equal to 6 hours with subsequent opioid infusion, or 3) ketamine initiated concomitantly or within 4 hours of opioid and total opioid duration less than 4 hours.

INTERVENTIONS: None.

MEASUREMENTS: Use of ketamine, analgesics, and sedatives were evaluated. Pain, sedation, and delirium assessments immediately before and during ketamine infusion were collected and compared with reported goals. Concomitant analgesics, sedatives, and psychotropics were recorded. Reported failures due to ineffectiveness and toxicity were collected.

MAIN RESULTS: Of 164 included patients, 88% never received a concomitant opioid infusion (primary analgosedation definition 1), 12% met alternative criteria for primary analgosedation (definitions 2 and 3). A majority, 68%, were surgical admissions and mean Acute Physiology and Chronic Health Evaluation III score was 90 (± 30). Median mechanical ventilation duration was 2.5 days (1.1-4.5) and ICU length of stay of 4.9 days (3-8). The median ketamine infusion dose and duration were 0.18 mg/kg/hr (0.1-0.3) and 30 hours (15.1-51.8). Concomitant infusions of propofol and dexmedetomidine were administered in 49% and 29% of patients, respectively. During ketamine infusion, the median percent of total pain scores at goal was 62% (33-96%), while 64% (37-91%) of Richmond Agitation Sedation Scale scores were at goal, and 47% of patients were Confusion Assessment Method-ICU positive during the ketamine infusion. Hallucinations were documented in 14% of patients and ketamine failure occurred in 11% of patients.

CONCLUSIONS: Ketamine may be an effective primary analgosedation option in intubated surgical ICU patients, but prospective randomized studies are needed to evaluate this strategy.