(947) Impact of Continuous Ketamine Infusions for Sedation During Mechanical Ventilation

Introduction: The SCCM PADIS Guidelines suggest continuous infusion ketamine for analgesia during mechanical ventilation (MV). Although some studies address its role as a sedative during MV, ketamine's effect on concomitant sedative and analgesic dosing and sedation goal attainment remains incompletely characterized. We evaluated the effect of continuous infusion ketamine at our institution, hypothesizing that it would be associated with reduced doses of other sedative and analgesic infusions and increased time at SAS goal.

Methods: In this IRB-approved, single-center retrospective analysis of patients receiving ketamine infusions for sedation over a two-year period, we included MV patients with a SAS goal of 3-4 who received ketamine infusions while in an ICU and on at least one continuous infusion of a sedative or analgesic. Demographics and sedative and analgesic use data during MV were collected from the electronic health record. The primary outcome was percent change in concomitant sedative requirements during the 12 hours before and after ketamine initiation. Secondary outcomes included SAS goal attainment and adverse effects. Concomitant sedative dosing and percent of time at SAS goal were evaluated using paired t tests while descriptive statistics were used to quantify adverse effects.

Results: 101 patients were included. Mean age was 57+/-15 years, weight was 95+/-29 kg, and 69% were male. 74%, 22%, and 4% of patients were in medical, surgical, and neuroscience ICUs, respectively. Patients were on 2+/-0.6 sedative and analgesic infusions before ketamine, with 83% receiving an opioid infusion. 61%, 37%, and 33% of patients received propofol, midazolam, and dexmedetomidine infusions, respectively. The median ketamine infusion rate was 10 (IQR, 6-20) mcg/kg/min. After ketamine initiation, propofol and midazolam doses decreased by 34% (p=0.006) and 26% (p=0.01), respectively. Dexmedetomidine and opioid doses did not change. Time at SAS of 3-4 increased by 12% (p=0.04). The most common adverse events potentially caused by ketamine were agitation followed by tachycardia, hypertension, and bronchorrhea.

Conclusions: After ketamine initiation, propofol and midazolam doses decreased while dexmedetomidine and opioid doses were unchanged, and time at goal SAS increased.