Prehospital Ketamine Use for Rapid Sequence Intubation: Are Higher Doses Associated With Adverse Events?

OBJECTIVE: Ketamine for rapid sequence intubation (RSI) is typically dosed at 1 to 2 mg/kg intravenously. The need to ensure dissociation during RSI led some to administer ketamine at doses greater than 2 mg/kg. This study assessed associations between ketamine dose and adverse events. METHODS: This multisite, retrospective study included adult subjects undergoing RSI with intravenous ketamine. Subjects were categorized into 2 groups: a standard ketamine dose (≤ 2 mg/kg intravenously) or a high dose (> 2 mg/kg intravenously). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for adverse events. RESULTS: Eighty subjects received standard-dose ketamine, and 50 received high-dose ketamine. The high-dose group had a significantly (P < .05) higher proportion of trauma patients, were younger, and had higher predose blood pressure compared with the standard-dose group. High-dose ketamine was associated with greater odds of adverse events including hypotension (OR = 7.0; 95% CI, 3.0-16.6), laryngospasm (OR = 10.8; 95% CI, 1.3-93.4), bradycardia (OR = 7.5; 95% CI, 1.5-36.6), repeat medications (OR = 12.9; 95% CI, 1.5-107.9), oxygen desaturation (OR = 6.0; 95% CI, 1.8-19.9), multiple attempts (OR = 3.2; 95% CI, 1.5-6.8%), and failed airway (OR = 3.6; 95% CI, 1.0-12.7). CONCLUSION: Ketamine at higher doses was associated with increased odds of adverse events. Studies assessing adverse events of ketamine at lower than standard doses in shock patients are needed.