How to Administer Low-Dose IV Ketamine for Pain in the ED

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).

Reference

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

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