Field Testing of the Compensatory Reserve Measurement Monitoring Capability: Results From the 2024 Army Warfighter...

The Compensatory Reserve Measurement (CRM) is a machine learning algorithm that provides continuous real-time arterial waveform feature analysis, reflecting an individual's ability to compensate for reduced circulating blood volume. Compensatory Reserve Measurement calculates a value from 100% to 0% that reflects the amount of compensatory reserve an individual has during blood volume reductions. The purposes of this field study were to assess the ability of warfighters to use the CRM for (1) triage of multiple casualties and (2) efficacy during the use in a battlefield urban setting scenario.

Ninety soldiers received ∼20 minutes of training on the scientific basis of the CRM and how to interpret displayed values. Warfighters included combat medics, combat lifesavers, and soldiers with no medical expertise. Groups of 2 to 3 soldiers were provided a tablet that displayed real-time CRM values of 3 casualties to simulate a mass casualty event (MASCAL) scenario. The CRM was displayed as a "fuel gauge" graphic that changed color from green-to-yellow-to-red as circulating blood volume decreased. Systolic, diastolic, and mean blood pressures, heart rate, blood oxygen carrying capacity, and respiratory rate were also displayed. Participants were instructed to press a "shock" button on the monitor screen when they recognized that the casualty had progressed to an unstable status (from green to yellow). Times of identified shock were recorded to the tablet. In addition, a qualitative assessment was conducted on CRM use by medics during a simulated hostile austere battlefield environment.

Despite vital signs remaining within clinically normal values in all 3 casualties, the order of shock identification was correctly assessed in 93% of the cases. Consistently high scores for operational usefulness included 90% agreement across participants that CRM increased the soldier's capability in the function of survivability. Combat medics successfully performed casualty triage during the field exercise.

The CRM provides combat medics with the ability to detect ongoing hemorrhage earlier compared to standard vital signs with discriminative capability for triage prioritization in MASCAL scenarios. Providing field personnel with this capability can improve the management and triage of critical care in combat casualties.