In this episode, I’ll discuss a recent trial of nebulized ketamine for analgesia in the ED.
A case series of 5 patients that received nebulized ketamine for analgesia in the emergency department has previously been published. Each patient experienced a decrease in pain from the baseline up to 120 minutes. The dose was not consistent; 3 patients received nebulized ketamine at 1.5 mg/kg, 1 patient at 0.75 mg/kg, and 1 patient at 1 mg/kg.
The bioavailability to nebulized ketamine ranges between 20–40% of IV route, so it is likely that the dose range of 0.75 to 1.5 mg/kg would provide analgesia without dissociative sedation.
Nebulized ketamine has been studied more in palliative care situations but there are potential advantages to this therapy in the ED. The nebulized route is less painful than IV or IM, while still providing for rapid and titratable administration.
Researchers recently published in Annals of Emergency Medicine a 3 arm randomized trial that compared 3 doses of nebulized ketamine (0.75 mg/kg, 1 mg/kg, and 1.5 mg/kg) administered via nebulizer in adult emergency department patients with moderate to severe acute and chronic pain.
120 patients were evenly split between the 3 groups.
The primary outcome included the difference in pain scores on an 11-point numeric rating scale between all 3 groups at 30 minutes. Secondary outcomes included the need for rescue analgesia (additional doses of nebulized ketamine or intravenous morphine) and adverse events in each group at 30 and 60 minutes.
The authors found that:
The difference in mean pain scores at 30 minutes between the 0.75 mg/kg and 1 mg/kg groups was 0.25 (95% confidence interval [CI] 1.28 to 1.78); between the 1 mg/kg and 1.5 mg/kg groups was −0.225 (95% CI −1.76 to 1.31); and between the 0.75 mg/kg and 1.5 mg/kg groups was 0.025 (95% CI −1.51 to 1.56). No clinically concerning changes in vital signs occurred. No serious adverse events occurred in any of the groups.
While this administration route will likely not become more popular than IV, this study adequately demonstrates the safety and efficacy of nebulized ketamine for pain the ED across all 3 doses studied. Therefore if I were to use nebulized ketamine for pain it would make sense to use the lowest dose, 0.75 mg/kg. It should be noted that the majority of patients in the study suffered from acute musculoskeletal pain from traumatic and nontraumatic origins. Although single doses were given in this study, the case series did involve some patients who received multiple doses.
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