Pre-hospital Utilization of Nebulized Sub-dissociative Dose Ketamine for Managing Acute Traumatic Extremity Pain: a Prospective Observational Study

Ketamine is a non-competitive N-methyl-D-aspartate (NMDA)/glutamate receptor complex antagonist that decreases pain by diminishing central sensitization, hyperalgesia, and "wind-up" phenomenon at the level of the spinal cord (dorsal ganglion) and central nervous system Ketamine administration in sub-dissociative doses (0.1-0.3 mg/kg) in prehospital settings and in the ED results in effective pain relief in patients with acute traumatic and non-traumatic pain, chronic non-cancer and cancer pain, and in patients with opioid-tolerant pain by virtue of providing anti-hyperalgesia, anti-allodynia, and anti-tolerance. Two commonly employed strategies of SDK administration in the ED include an intravenous push (IVP) dose (over 2-5 minutes), which is associated with relatively high rates of minor but bothersome psycho-perceptual side effects (feeling of unreality and dizziness), or short infusion (SI) given over 15 minutes with significantly reduced rates of unreality and preserved analgesic efficacy.

In the current study the investigators hypothesize that sub-dissociative-dose ketamine administered as a single agent via breath actuated nebulizer at the dose of 1.0 mg/kg will provide significant pain relief with minimal rates of side effects for patients with acute traumatic extremity injuries and will allow for alternative administration of effective analgesia especially in those settings for which intravenous or intraosseous routes are difficult or not necessary or when a delay in patient transport to a hospital is not ideal.

The primary outcome of this trial is the percent reduction in participant's pain scores at 30 minutes post medication administration.

STUDY DESIGN

Subjects: Patients 18 years of age and older transported by prehospital care providers to the ED with acute traumatic extremity injuries with a pain score of 5 or more on a standard 11- point (0 to 10) numeric rating scale. Patients will be enrolled by Emergency Medical Services (EMS) providers of Maimonides Medical Center (MMC) who are operating under the New York City 9-1-1 Regional Emergency Medical Advisory Committee (REMAC) auspices. Patient screening, enrollment, and data collection will be performed initially by advanced life support (ALS) paramedics and subsequently completed by study investigators upon arrival to the MMC emergency department. Emergency department pharmacist investigators will prepare PK-BAN packages that will be assigned to every ALS ambulance at the start of shift. The package will include a single ketamine 50mg/ml vial, blunt-tip needle and syringe, BAN device/tubing, and data collection sheet.