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Updated: Jul 3, 2026
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Integrated Compensatory Responses in a Human Model of Hemorrhage
Published on: November 20, 2016
Combat stress or hemorrhage? Evidence for a decision-assist algorithm for remote triage
Caroline A Rickards1, Kathy L Ryan, William H Cooke
1U.S. Army Institute of Surgical Research, Fort Sam Houston, TX 78234, USA. caroline.rickards@us.army.mil
Aviation, Space, and Environmental Medicine
|July 16, 2008
Summary
Pulse pressure (PP) changes can remotely distinguish bleeding soldiers from active ones, unlike high-frequency R-R interval spectral power (RRI HF). This finding aids remote triage for combat medics.
Area of Science:
- Physiology
- Biomedical Engineering
- Military Medicine
Background:
- Remote military triage requires distinguishing wounded from active soldiers.
- Traditional vital signs are insufficient for remote assessment.
- High-frequency R-R interval spectral power (RRI HF) and pulse pressure (PP) can track central hypovolemia.
Purpose of the Study:
- To test if RRI HF and PP changes differ between simulated hemorrhage and exercise.
- To evaluate their potential for remote distinction of bleeding vs. active soldiers.
Main Methods:
- 12 healthy subjects underwent progressive lower body negative pressure (LBNP) and cycle ergometer exercise.
- Continuous ECG and blood pressure monitoring.
- Exercise workloads matched LBNP-induced heart rate responses.
Main Results:
- RRI HF decreased similarly during both LBNP and exercise.
- Pulse pressure (PP) decreased significantly during LBNP (-30%) but increased during exercise (+20%).
Conclusions:
- Monitoring PP in combination with RRI HF can differentiate bleeding from active soldiers.
- Telemetry of these vital signs can support remote battlefield decision-making for medics.
