Clinical bottom line
Intravenous ketamine is a putative adjunct therapy for acute severe bronchospasm refractory to standard treatments in the emergency department (ED). Evidence, primarily from pediatric populations, suggests ketamine’s bronchodilatory and sedative properties may improve airway dynamics and clinical symptoms in severe asthma exacerbations. However, data remain limited and heterogeneous, with few high-quality randomized controlled trials in adults. Ketamine’s unique pharmacologic profile offers a potential option when conventional bronchodilators and corticosteroids fail, but its routine early use in acute severe bronchospasm requires further validation.
What the evidence shows
Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist with dissociative anesthetic effects, also exhibits bronchodilatory properties through smooth muscle relaxation and catecholamine release. Its use in acute severe asthma and bronchospasm has been explored mainly in pediatric emergency settings. Allen et al. (2005) conducted a randomized controlled trial in pediatric patients with acute severe asthma, demonstrating that intravenous ketamine improved pulmonary function and reduced respiratory distress scores compared to placebo. This study remains a key reference supporting ketamine’s efficacy in severe bronchospasm, although the sample size was modest and focused on children.
More recently, case reports and observational data have extended ketamine’s potential use to adults, including special populations such as pregnant patients with refractory bronchospasm (Johnson et al., 2023). These reports highlight ketamine’s rapid onset of bronchodilation and sedation, which may facilitate ventilation and reduce the need for intubation in severe cases.
Despite these promising findings, systematic reviews and guidelines have not yet established ketamine as a first-line or standard adjunct therapy for acute severe bronchospasm in the ED. The Oxford Medicine Online chapter on acute severe asthma (Redding et al., 2017) acknowledges ketamine’s potential but emphasizes the need for more robust adult data and standardized dosing protocols.
Ketamine’s safety profile in the ED is well characterized for procedural sedation (Udo et al., 2024), supporting its feasibility for use in acute respiratory distress scenarios. However, adverse effects such as emergence reactions, increased secretions, and cardiovascular stimulation require careful monitoring.
Caveats and uncertainty
The evidence base for intravenous ketamine in acute severe bronchospasm is limited by small sample sizes, heterogeneity in patient populations (mostly pediatric), and lack of large-scale randomized controlled trials in adults. The optimal dosing regimen, timing relative to other therapies, and patient selection criteria remain unclear. Most data derive from single-center studies or case series, which may introduce bias.
Ketamine’s bronchodilatory effect, while mechanistically plausible, has not been consistently demonstrated across all studies, and its impact on long-term outcomes such as hospital length of stay or mortality is unknown. Potential adverse effects, including psychomimetic symptoms and cardiovascular effects, may limit its use in certain patients.
Furthermore, ketamine should not replace established first-line therapies such as inhaled beta-agonists, anticholinergics, systemic corticosteroids, and oxygen supplementation. Its role is best considered as a rescue or adjunctive option in refractory cases.
How this may change practice
Emergency clinicians may consider intravenous ketamine as a rescue therapy for patients with acute severe bronchospasm unresponsive to standard treatments, particularly when intubation is being contemplated or when sedation and bronchodilation are simultaneously needed. Familiarity with ketamine’s dosing, monitoring requirements, and potential side effects is essential.
This evidence digest encourages cautious, hypothesis-generating use of ketamine in severe bronchospasm while awaiting more definitive adult data. Institutions might develop protocols incorporating ketamine for refractory cases, ideally within quality improvement frameworks or clinical trials.
Future research should focus on randomized controlled trials in adult ED populations, comparative effectiveness versus other adjunct therapies, and standardized dosing strategies to clarify ketamine’s role in acute severe bronchospasm management.