Tolerance to Lower Body Negative Pressure: Effects of Sex and Sufentanil

INTRODUCTION: Hemorrhage is a leading cause of death in the pre-hospital setting and is almost always accompanied by severe pain. Prior investigations have spotlighted two pivotal physiological influences that decrease tolerance to hemorrhage: 1) being female and 2) opioid administration, the latter of which decreases hemorrhage tolerance in animals but that has not been confirmed in humans. Therefore, this dissertation sought to 1) explore potential differences in autonomic responses between sexes to progressive central hypovolemia and 2) to examine whether sublingual sufentanil reduces tolerance to a simulation of hemorrhage (lower-body negative pressure; LBNP). METHODS: Participants for both studies were instrumented for continuous measurements of heart rate (electrocardiography), beat-to-beat blood pressure (finometer), and muscle sympathetic nerve activity (microneurography: radial nerve). Each underwent a double-blinded, randomized crossover study where they received either a placebo or drug on two different trial days. Data for the first study were obtained solely from the placebo arm of previous studies in our laboratory. For the second study, following the administration of a placebo or sufentanil, participants underwent LBNP to tolerance. Furthermore, following that LBNP challenge, to test the efficacy of sufentanil on pain ratings, each participant performed a cold pressor test. RESULTS: Females had a ~35% lower tolerance to LBNP compared to males (p=0.003), accompanied by a lower burst frequency (p=0.016). Sufentanil did not decrease tolerance to LBNP (p = 0.495), however, it attenuated perceived pain (p < 0.001), but not blood pressure responses (p = 0.334), to the cold pressor test. CONCLUSION: This dissertation demonstrated two primary findings. First, females have lower tolerance to LBNP, accompanied by attenuated sympathetic activation. Future studies should investigate the mechanism as to why females had lower sympathetic activation to simulated hemorrhage. Second, sublingual sufentanil did not decrease tolerance to LBNP in either sex, but did attenuate perceived cold pain, suggesting sufentanil may be an appropriate analgesic for a hemorrhagic injury.

Author dc:creator

• Jarrard, Caitlin Patricia

Contributors dc:contributor

• Smith, Scott Alan
• Crandall, Craig G.
• Zafereo, Jason
• Mizuno, Masaki
• Watso, Joseph C.

• Blood Pressure
• Cross-Over Studies
• Female
• Hypovolemia
• Lower Body Negative Pressure
• Male
• Sufentanil
• Analgesics, Opioid

Language dc:language

en

Identifier

1596185273

OAI identifier oai:identifier

oai:utswmed-ir.tdl.org:2152.5/10851