Currently available triage and monitoring tools are often late to detect life-threatening clinically significant physiological aberrations and provide limited data in prioritizing bleeding patients for treatment and evacuation. The Compensatory Reserve Index (CRI) is a novel means of assessing physiologic reserve, shown to correlate with central blood volume loss under laboratory conditions. The purpose of this study was to compare the noninvasive CRI device with currently available vital signs in detecting blood loss. Study subjects were soldiers volunteering for blood donation (n = 230), and the control group was composed of soldiers who did not donate blood (n = 34). Data collected before and after blood donation were compared, receiver operator characteristic curves were generated after either donation or the appropriate time interval, and areas under the curves (AUCs) were compared. Compared with pre-blood loss, blood donation resulted in a mean reduction of systolic blood pressure by 3% (before, 123 mmHg; after, 119 mmHg; P < 0.01). The CRI demonstrated a 16% reduction (before, 0.74; after, 0.62; P < 0.01). Heart rate, diastolic blood pressure, and oxygen saturation remained unchanged. The AUC for change in CRI was 0.81, 0.56 for change in heart rate, 0.53 for change in systolic blood pressure, 0.55 and 0.58 for pulse pressure and shock index, respectively. The AUCs for detecting mild blood loss at a single measurement were 0.73 for heart rate, 0.60 for systolic blood pressure, 0.62 for diastolic blood pressure, 0.45 for pulse oximetry, and 0.84 for CRI. The CRI was better than standard indices in detecting mild blood loss. Single measurement of CRI may enable a more accurate triage, and CRI monitoring may allow for earlier detection of casualty deterioration.
Among military advanced life support providers, self-confidence levels in procedure performance are positively associated with experience gained from manikins and supervised and unsupervised patient application. We were not able to demonstrate a clear benefit of an animal model in increasing self-confidence. A plateau was generally identified, indicating decreased benefit from the use of a particular training modality for a particular procedure. Modifying training regimens in light of these findings may help maximize the self-confidence of advanced life support providers more efficiently.
BACKGROUND
A walking blood bank (WBB) refers to the use of fellow combatants for battlefield blood donation. This requires pretesting combatants for infectious diseases and blood type. A fundamental prerequisite for this technique is that the donating soldier will suffer minimal physiological and mental impact. The purpose of the current study is to assess the effect of blood shedding on battlefield performance.
METHODS
This is a double‐blind randomized control trial. Forty Israel Defense Forces combatants volunteered for the study. Participants underwent baseline evaluation, including repeated measurement of vital signs, cognitive evaluation, physical evaluation, and a strenuous shooting test. Three weeks after the baseline evaluation, subjects were randomized to either blood donation or the control group. For blinding purposes, all subjects underwent venous catheterization for the duration of a blood donation. Repeated vital signs and function evaluation were then performed.
RESULTS
Thirty‐six patients were available for randomization. Baseline measurements were similar for both groups. Mean strenuous shooting score was 80.5 ± 9.5 for the control group and 82 ± 6.6 for the test group (p = 0.58). No clinically or statistically significant differences were found in tests designed to evaluate cognitive performance or physical functions. Vital signs taken multiple times were also similar between the test and control groups.
CONCLUSIONS
Executive, cognitive, and physical functions were well preserved after blood donation. This study supports the hypothesis that a WBB does not decrease donor combat performance. The categorical prohibition of physical exercise following blood donation might need to be reconsidered in both military and civilian populations.
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