Combat medic testing of a novel monitoring capability for early detection of hemorrhage

Abstract

BACKGROUND Current out-of-hospital protocols to determine hemorrhagic shock in civilian trauma systems rely on standard vital signs with military guidelines relying on heart rate and strength of the radial pulse on palpation, all of which have proven to provide little forewarning for the need to implement early intervention prior to decompensation. We tested the hypothesis that addition of a real-time decision-assist machine-learning algorithm, the compensatory reserve measurement (CRM), used by combat medics could shorten the time required to identify the need for intervention in an unstable patient during a hemorrhage profile as compared with vital signs alone. METHODS We randomized combat medics from the Army Medical Department Center and School Health Readiness Center of Excellence into three groups: group 1 viewed a display of no simulated hemorrhage and unchanging vital signs as a control (n = 24), group 2 viewed a display of simulated hemorrhage and changing vital signs alone (hemorrhage; n = 31), and group 3 viewed a display of changing vital signs with the addition of the CRM (hemorrhage + CRM; n = 22). Participants were asked to push a computer key when they believed the patient was becoming unstable and needed medical intervention. RESULTS The average time of 11.0 minutes (95% confidence interval, 8.7–13.3 minutes) required by the hemorrhage + CRM group to identify an unstable patient (i.e., stop the video sequence) was less by more than 40% (p < 0.01) compared with 18.9 minutes (95% confidence interval, 17.2–20.5 minutes) in the hemorrhage group. CONCLUSION The use of a machine-learning monitoring technology designed to measure the capacity to compensate for central blood volume loss resulted in reduced time required by combat medics to identify impending hemodynamic instability. LEVEL OF EVIDENCE Diagnostic, level IV.

Compensatory reserve detects subclinical shock with more expeditious prediction for need of life‐saving interventions compared to systolic blood pressure and blood lactate

“…Our results reveal that by using CRM over SBP and/or LAC, we were able to better predict those progressing to shock and requiring LSI. Although not temporally quantified in the current study, this earlier recognition has been shown to have significant translation in earlier identification of shock by civilian paramedics 29 and combat medics 30 …”

“…Although not temporally quantified in the current study, this earlier recognition has been shown to have significant translation in earlier identification of shock by civilian paramedics 29 and combat medics. 30 Researchers have attempted to better predict or appreciate this "occult" shock through many devices such as tissue oxygen (StO 2 ) monitoring or lab analyses such as LAC and base deficit. Although these methods have shown promise, there remain questions in regards to their reliability and/or usefulness in the pre-hospital or forward-combat setting.…”

Efficacy of the compensatory reserve measurement in an emergency department trauma population

“…The high potential for delays in early and rapid medical evacuation in addition to mass casualty scenarios will require individualized triage decision to optimize medical resources and successfully execute prolonged field care. Integrating the CRM into prehospital medical monitoring on the battlefield could fill this capability gap by providing a medic with real‐time clinical status of injured casualties that will lead to earlier recognition for the need to intervene 33,34 . Such continuous monitoring of CRM could translate to optimizing combat casualty care of warfighters in austere, kinetic, and contested battlefield settings.…”

“…Integrating the CRM into prehospital medical monitoring on the battlefield could fill this capability gap by providing a medic with real-time clinical status of injured casualties that will lead to earlier recognition for the need to intervene. 33,34 Such continuous monitoring of CRM could translate to optimizing combat casualty care of warfighters in austere, kinetic, and contested battlefield settings.…”

Compensatory reserve and pulse character: Enhanced potential to predict urgency for transfusion and other life‐saving interventions after traumatic injury

“…This dynamic analysis applies a scale from 0% to 100% where 100% represents a complete capacity to compensate (e.g., a “full” fuel tank) and 0% represents the point where decompensated shock occurs. A potential for a color‐coded dashboard can provide for more rapid detection of where the patient lies along this cascade 17–20 . “Green” represents a reserve range of 100%–60%, “yellow” represents a reserve range of 60%–30%, and “red” represents a reserve range of 30%–0% reflecting the continuum toward decompensation.…”