Ketamine for Sedation in Mechanically Ventilated Patients

ABSTRACT

INTRODUCTION: The use of ketamine as a sedative agent has increased dramatically in patients who are mechanically ventilated (MV) due to COVID-19 in intensive care units (ICU). Ketamine primarily acts as an NMDA receptor antagonist that blocks the excitatory effects of glutamate. In comparison to other sedatives, ketamine has a more favorable hemodynamic profile and does not produce significant respiratory depression. The study sought to analyze the impact of initiating ketamine continuous infusions for sedation in MV patients on co-sedation dosing. METHOD(S) This was a single-center, retrospective, observational study. All MV patients admitted to the medical intensive care unit from October 1st, 2019 to October 31st, 2021 who received ketamine continuous infusions for sedation for more than 12 hours were be eligible for inclusion. RESULT(S) Of 167 patients identified, 76 (45.5%) patients were included. The average ketamine infusion rate was 0.65 mg/kg/hr and average duration was 3.9 days. At the start of ketamine, 74 patients were on fentanyl, 27 (36.5%) of those patients were successfully weaned off fentanyl (10.8%) or had a decrease in infusion rate (25.7%). A total of 47 patients were on propofol, 39 (83%) patients were successfully weaned off propofol (55.3%) or had a decrease in infusion rate (25.7%). Seventeen patients were on midazolam infusions, of those, 12 (70.6%) patients were successfully weaned off (52.9%) or had a decrease in rate (17.6%). There were 15 patients on dexmedetomidine, 6 (40%) patients were successfully weaned off (20%) or had a decrease in infusion rate (20%). At the start of ketamine, 71 patients were on norepinephrine + vasopressin + epinephrine. Of the 71 patients, 48 (67.6%) were able to wean off vasoactive agents or had a decrease in rate. Twelve patients had documented emergence reactions or adverse reactions during infusion. CONCLUSION(S) Ketamine continuous infusion as an adjunct analgosedative agent resulted in successful weans off co-sedative agents or in decreased infusion rates. It was particularly impactful on propofol and midazolam continuous infusions as more than 50% of patients on these two agents were successfully weaned off.