Analgesics in the Pre-hospital Setting: Implications on Hemorrhage Tolerance - Fentanyl

Pain management on the battlefield is critical for the wellbeing of the soldier. Given that a hemorrhagic injury on the battlefield is virtually always associated with pain, it is paramount that the selected pain medication does not disrupt appropriate physiological mechanisms that are beneficial towards the maintenance of blood pressure and vital organ blood flow during that hemorrhagic insult. Current guidelines for the selection of pain medications of a hemorrhaging soldier are based upon limited scientific evidence, with the vast majority of supporting studies being conducted on anesthetized animals. Thus, the interaction between hemorrhagic shock and pain medications commonly employed on the battlefield is yet to be determined in the conscious humans.

With this background, we will test the hypothesis that fentanyl will impair the capacity for a conscious human to tolerate a hemorrhagic insult.

The obtained data will provide the necessary scientific evidence in humans to support the Committee on Tactical Combat Casualty Care (CoTCCC) guidelines on the analgesic of choice for moderate to severe injuries where the casualty is in hemorrhagic shock. Notably, such data will identify the analgesic that least compromises a human's ability to tolerate a hemorrhagic insult, ultimately providing critical information to the combat medic on which analgesic should be employed for such an injury.

Inclusion criteria

• Healthy
• Non-obese (body mass index less than 30 kg/m2)
• Body mass greater than or equal to 65 kg

Exclusion criteria

• Subjects who have cardiac, respiratory, neurological and/or metabolic illnesses
• Any known history of renal or hepatic insufficiency/disease
• Pregnancy or breast feeding
• Current smokers, as well as individuals who regularly smoked within the past 3 years
• Positive urine drug screen
• Currently taking pain modifying medication(s)