Use of Low-Dose Ketamine for Pain Management in an Emergency Department
Background/Purpose: In the emergency department (ED), many barriers exist to pain management. Non-steroidal anti-inflammatory drugs and acetaminophen often cannot provide enough relief, while opioid analgesics are hindered by side effects, dependency, and tolerance. A non-competitive NMDA receptor antagonist, ketamine has historically been used for sedation and anesthesia in rural settings or in those with limited resources. Ketamine's unique safety profile and variety of dosage forms indicate its potential role in pain management. An evaluation was conducted of ketamine's use in low doses to treat pain in an emergency department with the third-greatest annual census in Miami-Dade county.
Methodology: A retroactive report was generated to identify patients who received ketamine in the Homestead Hospital ED between June 2014 and June 2015. Subjects included those treated with low-dose ketamine (LDK) for pain in doses less than 1 mg/kg. Pain evaluation tools included a one-to-ten visual analogue scale for adults, the Wong-Baker FACES Pain Rating Scale for children and adults unable to communicate pain verbally, and provider documentation. Patients' charts were reviewed to determine how LDK was used to treat pain, safety, and effectiveness. Descriptive statistics were generated using Microsoft Office Excel 2007.
Results: Of 114 subjects, 24 met inclusion criteria. A total average dose of 0.375 mg/kg was administered for eight distinct indications. Ketamine monotherapy reduced an average baseline pain rating of Severe to that of Mild upon discharge, in a manner similar to coadministration with analgesics and sedative agents. Two adverse drug events were reported for separate patients; each was mild in nature.
Conclusion: LDK was safely administered to treat a variety of indications. The drug was effective in doses < 1 mg/kg for emergency analgesia. More data will be needed to definitively determine the safety of ketamine at low-doses and how to maximize its risk-benefit ratio.