Low-Dose Ketamine Infusion for Emergency Department Patients With Severe Pain

Pain Med. 2015 Jul;16(7):1402-9. doi: 10.1111/pme.12705. Epub 2015 Feb 3.

Abstract

Objective: Use of low-dose ketamine infusions in the emergency department (ED) has not previously been described, despite routine use in perioperative and other settings. Our hypothesis was that a low-dose ketamine bolus followed by continuous infusion would 1) provide clinically significant and sustained pain relief; 2) be well tolerated; and 3) be feasible in the ED.

Methods: We prospectively administered 15 mg intravenous ketamine followed immediately by continuous ketamine infusion at 20 mg/h for 1 hour. Optional morphine (4 mg) was offered at 20, 40, and 60 minutes. Pain intensity, vitals signs, level of sedation, and adverse reactions were assessed for 120 minutes.

Results: A total of 38 patients were included with a median initial numerical rating scale (NRS) pain score of 9. At 10 minutes, the median reduction in pain score was 4, with 7 patients reporting a score of 0. At 60 and 120 minutes, 25 and 26 patients, respectively, reported clinically significant pain reduction (decrease NRS score > 3). Heart rate, blood pressure, respiratory rate, and oxygen saturation remained stable. Mild or moderate side effects including dizziness, fatigue, and headache were common. Patient satisfaction was high; 85% reported they would have this medication again for similar pain.

Conclusion: A low-dose ketamine infusion protocol provided significant pain relief with mostly mild side effects and no severe adverse events.

Keywords: Acute Pain; Analgesia; Emergency Service; Intravenous Infusions; Ketamine.

MeSH terms

  • Adult
  • Aged
  • Analgesics / therapeutic use
  • Analgesics, Opioid / administration & dosage
  • Blood Pressure / drug effects
  • Dizziness / chemically induced
  • Dose-Response Relationship, Drug
  • Emergency Service, Hospital*
  • Fatigue / chemically induced
  • Female
  • Headache / chemically induced
  • Heart Rate / drug effects
  • Humans
  • Infusions, Intravenous / methods
  • Ketamine / administration & dosage
  • Ketamine / adverse effects
  • Ketamine / therapeutic use*
  • Male
  • Middle Aged
  • Morphine / administration & dosage
  • Oxygen / metabolism
  • Pain / drug therapy*
  • Pain Management / adverse effects
  • Pain Management / methods*
  • Pain Management / psychology
  • Pain Measurement / methods
  • Patient Satisfaction / statistics & numerical data*
  • Prospective Studies
  • Respiratory Rate / drug effects
  • Time Factors
  • Treatment Outcome

Substances

  • Analgesics
  • Analgesics, Opioid
  • Ketamine
  • Morphine
  • Oxygen