Introduction: Ketamine has a theorized benefit in severe asthma exacerbation due to bronchodilation produced by catecholamine-induced beta-2 receptor agonism. Due to this mechanism, it may prevent intubation and reduce peak airway pressures, although literature is scarce and described dosing varies widely. The aim of this study was to describe the dosing, timing, and outcomes for patients receiving ketamine for severe asthma at our institution.
Methods: This retrospective, single-center analysis included patients receiving ketamine within the medical intensive care unit a large academic medical center from January 2018-December 2024 was performed for status asthmaticus. Data was collected on baseline characteristics, ketamine dosing, other guideline-recommended therapies received prior to ketamine initiation, clinical outcomes, and safety events through chart review. Descriptive statistics were utilized to characterize results.
Results: Over the study period, 23 patients received ketamine during 26 separate encounters for severe asthma. The cohort was mostly female (65.2%), with a median age of 38 years. Anxiety was the most common comorbidity (26.9%) and no patients had coronary artery disease. All patients received inhaled bronchodilators and 24/26 received systemic steroids prior to ketamine. The median ketamine bolus dose was 0.34 mg/kg and the median starting infusion rate was 0.3 mg/kg/hr. Among patients initiated on ketamine while on non-invasive ventilation, 10/15 (67%) did not progress to endotracheal intubation. Most patients who (67%) received ketamine while intubated had elevated peak airway pressures. No patients had to discontinue ketamine due to adverse effects.
Conclusions: Ketamine appears to be a safe, reasonable option for refractory status asthmaticus at our institution. It may be utilized in patients refractory to guideline-directed therapy, and infusion adjustments performed based on ventilator mechanics if intubated. It may be of benefit in this patient population as a potential intubation-sparing strategy or for those with high peak airway pressures, with boluses of 0.3-1.0 mg/kg and infusion rates of 0.3-2.0 mg/kg/hr being utilized in this cohort. An institutional guideline was implemented to help guide optimal dosing practices.
