Fentanyl vs. Low-Dose Ketamine for the Relief of Moderate to Severe Pain in Aeromedical Patients

Often, patients transported by aeromedical systems do not receive enough medication to control and relieve their pain. The purpose of this study is to determine if pain treatment with intravenous (IV) ketamine is a better way to treat aeromedical patients' pain than the current treatment practices.

Specific Aims: The aim of this study is to determine the efficacy, side effects and safety of sub-dissociative doses of ketamine in controlling acute traumatic pain in patients transported by an aeromedical system when compared to standard doses of fentanyl.

Research Hypothesis: Aeromedical transport patients with acute pain treated with intravenous ketamine show a clinically significant difference in mean numeric rating scale (NRS) pain scores as compared to those treated with fentanyl and show no increase in adverse events.

Background and Significance: Treatment of acute pain in aeromedical transport patients is important. Treatment may be limited by real or perceived concerns regarding analgesic side effects including sedation, loss of airway maintenance, and negative hemodynamic consequences. Ketamine used in sub-dissociative doses has strong analgesic properties while maintaining protective airway reflexes and demonstrating minimal adverse hemodynamic effects. It has been suggested as an ideal pre-hospital analgesic. Current literature regarding its use in the pre-hospital environment is limited.

Experimental Design: This prospective, double-blind, randomized trial compares 0.3 mg/kg of intravenous (IV) ketamine to 1 mcg/kg of IV fentanyl in adult aeromedical transport patients who require pain control. The primary outcome measure will be the change in NRS pain scores at ten minutes compared between the two groups. Secondary endpoints will include rates of adverse events, differences in the slope of NRS scores over time, the total amount of fentanyl/kg body weight/minute of flight required, overall research participant satisfaction with their level of pain relief at the end of the flight, and the subjective ranking of pain recall in comparison to other aspects of the patient's overall episode of care (pre-hospital, emergency department, inpatient, and post-discharge care), as measured at 30 days.

Data Analysis: Categorical variables will be analyzed using chi-square and Fisher's exact test. Means of normally distributed variables will be compared using Student's t-test, and distributions of non-normally distributed variables will be compared using Mann-Whitney U. Bayesian generalized linear mixed modeling will be employed to model the time-dependent change in NRS scores between intervention groups while accounting for the autocorrelation inherent in a repeated measures design. SAS statistical software (SAS v. 9.2, Cary, NC) and WinBUGS software will be used for all analyses.

Eligibility Criteria:
Inclusion Criteria:

* Age \> 18 years
* Moderate to severe acute, traumatic pain (self-reported NRS \> 5)
* Ability to provide informed consent in English
* Flight destination to University of Utah Medical Center

Exclusion Criteria:

* Inability to use the NRS pain rating scale
* Historical or acute myocardial infarction or ischemia
* Ongoing hypertensive emergency
* Unconsciousness
* Allergic reaction to ketamine
* Increased intracranial or intraocular pressure
* Known pregnancy
* Prisoner