Biological Response to Stress During Battlefield Trauma Training: Live Tissue Versus High-Fidelity Patient Simulator.

Introduction: Tactical Combat Casualty Care (TCCC) training imposes psychophysiological stress on medics. It is unclear whether these stress levels vary with the training modalities selected. It is also unclear how stress levels could have an impact on medical performance and skill uptake.

Materials And Methods: We conducted a pilot study to compare the effects of live tissue (LT) with a high-fidelity patient simulator (SIM) on the level of stress elicited, performance, and skill uptake during battlefield trauma training course in an operating room (OR) and in a simulated battlefield scenario (field). In the report, we studied the effects of training modalities and their changes on stress levels by measuring different biomarkers (salivary amylase, plasma catecholamines, and neuropeptide Y) at various time points during the trauma training course.

Results: We found that the training resulted in significant psychophysiological stress as indicated by elevated levels of various biomarkers relative to baseline immediately after both OR and field assessment (p < 0.05). Compared with pre-OR levels, the LT training in the OR resulted in significant increases in the plasma levels of epinephrine, norepinephrine, and neuropeptide (p = 0.013, 0.023, 0.004, respectively), whereas the SIM training in the OR resulted in significant increases in the plasma levels of norepinephrine and neuropeptide (p = 0.003 and 0.008). Compared with pre-field levels, we found significant increases in plasma epinephrine concentration in the SIM group (p = 0.016), plasma norepinephrine concentration in the LT group (p = 0.015), and plasma neuropeptide Y concentration in both LT (p = 0.006) and SIM groups (p = 0.029). No differences in the changes of biomarker levels were found between LT and SIM groups in the OR and field. Compared with pre-field levels, the testing on the same modality as that in the OR in the simulated battlefield resulted in significant increases in norepinephrine and neuropeptide levels (p = 0.013 and 0.015), whereas the testing on different modalities resulted in significant increases in amylase, epinephrine, and neuropeptide levels (p = 0.016, 0.05, 0.018, respectively). There was a significantly larger increase in plasma norepinephrine concentration (p = 0.031) and a trend toward a greater increase in the salivary amylase level (p = 0.052) when the field testing involved a different modality than the OR compared with when OR and field testing involved the same modality. Although most of the biomarkers returned to baseline levels after 24 h, plasma norepinephrine levels remained significantly higher regardless of whether field testing occurred on the same or different modality compared with OR (p = 0.040 and 0.002).

Conclusion: TCCC training led to significant increase in psychophysiological stress, as indicated by elevated levels of various biomarkers. The training modalities did not result in any differences in stress levels, whereas the switch in training modalities appeared to elicit greater stress as evidenced by changes in specific biomarkers (amylase and norepinephrine). A comparative study with a larger sample size is warranted.