Back in 2015, Dr. Sergey Motov’s (@painfreeED) group published a study demonstrating the efficacy of low-dose ketamine compared to morphine for analgesia in the ED. Here’s my quick analysis of that study as a UMEM pearl. The question, though, is how best to administer the 0.3 mg/kg IV ketamine dose while minimizing the risk of adverse effects.
Fortunately, Dr. Motov’s group has just published a follow-up study addressing that exact question.
What They Did
- Prospective, randomized, double-blind, double-dummy trial comparing safety and analgesic efficacy of IV low-dose ketamine given as a push dose (over 5 minutes) versus given as a short infusion mixed in 100 mL 0.9% sodium chloride (over 15 minutes)
- Pain scores, vital signs, and adverse effects were recorded at baseline, 5, 15, 30, 60, 90, and 120 minutes
- Overall rates and specific severity levels of side effects were recorded in accordance with the Side Effects Rating Scale for Dissociative Anesthetics (SERSDA)
- Patients < 46 kg or > 115 kg were excluded.
What They Found
- 24 patients were enrolled in each group
- At 5 min:
- Median severity of feeling of unreality was 3.0 on SERSDA scale for the IV push group versus 0.0 for the short infusion group (p = 0.001).
- Median sedation on RASS scale was greater in IV push group −2.0 versus 0.0 in short infusion group (p = 0.01).
- Decrease in mean pain scores from baseline to 15 min was similar across groups.
- No difference between groups for changes in vital signs or need for rescue medication.
Application to Clinical Practice
If you’re using low-dose ketamine for acute pain in the ED, or developing guidelines for its use, administer it in 100 mL over 15 minutes.
Note: A second study utilized this same approach with positive results (J Emerg Med 2017).
Motov S, Mai M, Pushkar I, et al. A prospective randomized, double-dummy trial comparing intravenous push dose of low dose ketamine to short infusion of low dose ketamine for treatment of moderate to severe pain in the emergency department. Am J Emerg Med. 2017 Mar 3. Epub ahead of print. PMID 28283340