Low‐Dose Ketamine Infusion for Emergency Department Patients with Severe Pain

• Published in: Pain medicine (Malden, Mass.) Mass.), 2015-07, Vol.16 (7), p.1402-1409
• Main Authors: Ahern, Terence L., Herring, Andrew A., Miller, Steve, Frazee, Bradley W.
• Format: Article
• Language: English
• Subjects: Acute Pain; Adult; Aged; Analgesia; Analgesics - therapeutic use; Analgesics, Opioid - administration & dosage; Blood Pressure - drug effects; Dizziness - chemically induced; Dose-Response Relationship, Drug; Emergency Service; Emergency Service, Hospital; Fatigue - chemically induced; Female; Headache - chemically induced; Heart Rate - drug effects; Humans; Infusions, Intravenous - methods; Intravenous Infusions; Ketamine; Ketamine - administration & dosage; Ketamine - adverse effects; Ketamine - therapeutic use; Male; Middle Aged; Morphine - administration & dosage; Oxygen - metabolism; Pain - drug therapy; Pain management; Pain Management - adverse effects; Pain Management - methods; Pain Management - psychology; Pain Measurement - methods; Patient satisfaction; Patient Satisfaction - statistics & numerical data; Prospective Studies; Respiratory Rate - drug effects; Time Factors; Treatment Outcome
• ISSN: 1526-2375; 1526-4637
• DOI: 10.1111/pme.12705

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