(1012) Evaluation of Ketamine Monotherapy Versus Usual Care for Sedation in Mechanically Ventilated Adults

Introduction: Ketamine (KET) is a sedative and analgesic agent sometimes used during mechanical ventilation (MV). Data describing efficacy of continuous infusion (CIVI) KET for sedation indicates sedative and analgesic sparing effects. However, use of CIVI KET monotherapy for sedation compared to usual care (propofol and dexmedetomidine) is limited.

Methods: This two-center, retrospective study included adult, MV patients who received a minimum of 12 hrs of CIVI sedative monotherapy (KET or usual care [UC]). The primary outcome was proportion of Richmond Agitation Sedation Scale (RASS) scores within goal at 24 hrs. Secondary outcomes included rates of under- and oversedation, proportion of critical care pain observation tool (CPOT) scores at goal, ventilator- and delirium-free days, ICU and hospital length of stay (LOS), and mortality.

Results: The study included 84 (40 KET; 44 UC) patients. Mean SOFA score was higher in the KET cohort (9±3.4 vs 7±3.8; P=0.02) and duration of sedation monotherapy was similar between groups (KET, 30.2[18.6-60.5] vs UC, 34.8[18.6-57.0] hrs; P=0.97). Proportion of RASS in goal at 12 hrs (0.80[0.5-1.0] vs 0.37[0.1-0.6]; P< 0.001) and 24 hrs (0.79[0.5-1.0] vs 0.47[0.1-0.7]; P=0.004) was higher with KET. Proportion of time undersedated (0[0-0.1] vs 0[0-0.1]; P=0.97) and in goal CPOT (0.83[0.8-1.0] vs 0.92[0.7-1.0]; P=0.70) was not different between KET and UC, however patients had proportionally less oversedation in the KET group (0.15[0-0.4] vs 0.43[0.3-0.8]; P< 0.001). KET and UC groups had similar ventilator-free (11[4-20] vs 7[3-13]; P=0.17) and delirium-free (13[8-23] vs UC, 11[8-21]; P=0.59) days, as well as ICU (12[7-19] vs 11[5-19]; P=0.41) and hospital (19[13-28] vs 15[10-26]; P=0.41) LOS. Similar rates of ICU (8[19.5%] vs 8[18.2%]; P=0.88) and hospital (10[24.4%] vs 9[20.5%]; P=0.66) mortality were noted between KET and UC.

Conclusions: CIVI KET monotherapy resulted in more time within goal sedation and less time oversedated compared to UC in MV patients. Ventilator- and delirium-free days, ICU and hospital mortality, LOS, and hemodynamics were similar between groups. Ketamine demonstrated similar efficacy and safety to usual care. Larger, prospective, and adequately powered studies are needed to establish the optimal place in therapy for CIVI KET monotherapy during MV.