Discussion
Stress is frequently defined as a state of unacceptable divergence between perceived demands and capabilities to adapt.5 Stressful simulation training can affect the performance of healthcare professionals in different settings.6 High-risk environments of aviation and nuclear power have embraced high fidelity simulation training for decades. With aviation simulators, the effect of stress inoculation training on anxiety and performance was reviewed in 1996 with a meta-analysis of nearly 2000 participants. Results indicated that stress inoculation training, a cognitive behavioral approach to stress management, was an effective means for reducing performance anxiety, reducing state anxiety, and enhancing performance under stress.7 More recently, the Defense Health Board, Office of the Assistant Secretary of Defense Health Affairs reported that “Simulation training is also important for improving team effectiveness, specifically with low-frequency, high acuity emergency situations as the success of these complex procedures depends upon the entire surgical team, not only the surgeon.”8 Our data with a 6-day hyper-realistic scenario to improve surgical trauma team performance provides additional information in support of high fidelity medical training. The training curriculum and environment were truly realistic and stress provoking as indicated by increases in salivary cortisol and changes in sAA obtained with multiple longitudinal samples from a large number of subjects (n=99).
Cortisol steroid hormone is released in response to stress (fear/avoidant-related activation) and salivary cortisol concentrations have shown to be synchronous with serum cortisol levels.9 In the current study, a substantial increase in cortisol during the initial simulation was apparent, followed by a decline (figure 5). Specifically, there was a 41% increase in salivary cortisol from pre-post, followed by a decline at 20 minutes (19%) and 40 minutes near recovery (8%). In posthoc comparisons, a difference pre-post vs. pre-20 minutes (p<0.05) as well as pre-post vs. pre-40 minutes (p<0.001) was detected. By contrast, on the last day 6 simulation (same simulation as day 1), there was no statistically significant decline from baseline in cortisol levels. The results of this study demonstrate that the hyper-realistic immersive training environment elicited various levels of physiological stress to the participants. These findings also raise the possibility for habituation of the cortisol stress response with repeated exposure, implying possible stress adaptation, as a result of exposure to hyper-realistic simulation.
A notable decrease in sAA occurred during initial stressful learning situations and continued through early recovery in simulation 1 (figure 5). Specifically, there was a 9% decline in sAA from pre-post, which continued in a downward trajectory at 20 minutes (−21%) and 40 minutes recovery (−20%). In posthoc comparisons, there was a difference pre-post vs. pre-20 minutes (p<0.05) and a marginal difference in pre-post vs. pre-40 minutes (p=0.06). By contrast, no differences in sAA were observed between time points during SIM 6 which was the same scenario as SIM 1. In comparing sAA responses between SIMs, SIM 1 versus SIM 6 were different at the pre-20 minutes and pre-40 minutes times (p<0.05).
sAA is primarily reflective of the sympathetic stress response (approach-related activation). There is an association between changes in sAA during exposure to stressful stimulus and changes in the anxiety state. sAA is usually thought to increase quickly (ie, less than 5 minutes) after exposure to an acute stressful stimulus and return rapidly to baseline (ie, less than 15 minutes) during calming conditions. More specifically, sAA was shown to increase 220% with a corresponding increase of 17% systolic blood pressure in 15 patients undergoing planned C sections.10 Psychosocial stress has been shown to increase salivary α amylase independently from plasma norepinephrine levels.11 As the parotid gland is innervated by both sympathetic and parasympathetic systems, decreases in sAA have also been reported in response to stress.12 Multiple confounding factors may be influencing our data such as time of day (sAA levels highest in the morning) and smoking (decreases sAA levels) with caffeine, exercise and food increasing SAA levels. Salivary flow rate, age, and sex are reported to have little influence. As with salivary cortisol, the authors think that data imply potential habituation of the sAA stress response with repeated exposure, implying possible stress adaptation. Laporta and Hoang have shown somewhat similar results for salivary cortisol and α-amylase changes on medical student trainees undergoing hyper-realistic training.2–4
Our stress hormone findings are similar to another high-fidelity simulation study of 14 emergency medicine physicians and 27 paramedics. Cortisol values showed a gradual and statistically significant reduction over time, whereas sAA showed significant increases with each scenario; however, reductions followed each increase, indicating no clear trend.13
Along with habituation to stress, team performance was documented by specific metric improvements. Resuscitation time decreased by 10 minutes to an average of 13.91 minutes—approaching the mean evaluation time of 10.33 minutes for a highly experienced trauma team in a level 1 DoD facility.14 This is a significant clinical finding as rapid, effective trauma resuscitations decrease patient morbidity and mortality. Critical errors in the standardized scenarios also significantly decreased from 5 to 1, which has an immediate impact with improved injury pattern recognition, hemorrhage control, and airway/chest tube management. Due to the high-fidelity Human Worn Surgical Simulator “Cut Suit,” improved surgical procedure accuracy and intraoperative team problem solving was evaluated by subject matter expert observers. Immediate constructive critiques, coupled with video-feedback allowed teams to remediate and improve.
As for written knowledge assessment with the same 25 question multiple-choice examination taken by all participants pre and post-course, the largest improvement in test scores were noted in US Navy Hospital Corpsman/ US Army “Medic” enlisted medical technicians (26%) and Registered Nurses (25%) compared with physicians (11%) (table 2). The US Army Forward Surgical Team, a more senior in age unit with individuals engaged in trauma care in their civilian roles, showed a nearly 16% overall improvement indicating that trauma experienced individuals will benefit from a hyper-realistic experience.
The psychometric surveys were administered before the course, on day 3 and on conclusion on day 6 to assess changes in attitudes, resilience, cohesion, and stress-related psychological variables. The survey questions (online supplementary table 2) were based on published normative scales.15–21 Analyses conducted on the entire sample showed statistically significant increases in combat and unit readiness, unit and vertical cohesion, and team communication and leadership quality. Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS) processes based on principles of team structure (communication, leadership, situation monitoring, and mutual support) were emphasized.22 Effects of training on perceived stress were not reported by the participants to vary significantly with the 6 days of training which contrasts to the cortisol and α-amylase stress biomarker data. The authors think that the ingrained military “macho” fearless mentality may be contributing to the denial of self-reporting honest stressful feelings. Although no established criteria exist for clinical significance on these measures, in the experience of the Naval Center for Combat and Operational Stress Control, increases of 5% on similar measures (eg, engagement, leadership satisfaction, cohesion) typically correspond to observable differences in group functioning. This project has generated information on hyper-realistic training simulations effects on important psychological constructs that are crucial to group performance.
Strengths of this study include the relatively large sample size (n=99) for medical simulation research coupled with 6 days of multifaceted longitudinal data on individual subjects. Although the subjects were US Military members with formal rank structures, interactions follow a standard healthcare team hierarchy of physician, nurse, and medical technician. Challenges to the study involve lack of a control group that would evaluate 6 days of similar curriculum training not in a hyper-realistic environment. Certainly, any training experience can improve test scores, but this study focused on the complexities of human interactions in stressful life-threatening surgical trauma environments. Additional studies are required to evaluate the most time-efficient and cost-effective strategy. Lessons learned from previous and ongoing conflicts require realistic team-oriented training to manage complex trauma patients in both civilian and military mass casualty situations.23 24 In conjunction with the American College of Surgeons, Knowledge, Skills, and Abilities criteria have been developed at the Uniformed Services University of the Health Sciences to address the perishable surgical skills required in a combat zone and provide core metrics for trauma care providers.8 Integration and closer cooperation of military and civilian trauma systems will improve patient outcomes.25 More generalized applications of hyper-realistic immersive simulation training for healthcare providers may improve team communication, reduce iatrogenic medical errors, and increase patient safety.
