Abstract
Ketamine is a dissociative anesthetic often used for airway management in trauma. While perceived to preserve hemodynamic stability, concerns exist regarding its effects on intracranial pressure and cardiac output in critically ill patients. There is a lack of studies evaluating outcomes after ketamine administration in the setting of traumatic brain injury (TBI). This study aimed to investigate the effects of ketamine on outcomes and physiological responses in a large cohort of TBI patients. We hypothesized that ketamine administration would not be associated with differences in survival, vital signs, or disposition outcomes compared with other induction medications when administered following TBI. This was a retrospective, observational study utilizing data from the Linking Investigations in Trauma and Emergency Services registry (2017-2021). Subjects were divided into two groups: those who received only ketamine (n = 429) and those who received other induction medications (etomidate and/or propofol; n = 993). We compared 24-h mortality, initial in-hospital vital signs (systolic blood pressure [SBP], respiratory rate, heart rate, and Glasgow Coma Scale [GCS]), and hospital discharge disposition; a propensity score analysis adjusted for potential confounders including race, injury type, pre-hospital GCS, initial pre-hospital SBP and site location. Ketamine-exposed subjects were younger and presented with a worse clinical profile, including lower pre-hospital GCS (5 vs. 6, p < 0.01) and lower SBP (126.5 vs. 144.0 mmHg, p < 0.01) compared with the ketamine-unexposed group. Unadjusted analysis showed a significantly higher 24-h mortality rate in the ketamine-exposed group (3.5% vs. 1.4%, p = 0.02), as well as lower initial in-hospital vital signs. After propensity score adjustment, the odds of 24-h mortality remained significantly higher for the ketamine-exposed group (OR 2.358, p = 0.042). Hospital discharge disposition was not different between groups in any analysis. In this retrospective analysis, ketamine administration for pre-hospital airway management in TBI patients was associated with an increased 24-h mortality and lower in-hospital SBP, even after adjusting for baseline differences. However, injury severity and the length of time examined for mortality may explain the significant mortality association for ketamine in this study. Prospective studies are needed to examine the relationship between ketamine administration and mortality following TBI.