Discussion

In the present study, it was found that the most common cause of blunt trauma included motor vehicle crashes and of penetrating trauma included gunshot wounds/stabbings. The source of hemorrhage for most patients was the abdomen, chest, and/or a limb/extremity. Roughly one-third of patients required at least one prehospital intervention including tourniquet placement for hemorrhage control. Patients in the current study also experienced a median wait time of six minutes for EMS to arrive and a median of 60 minutes until reaching definitive care, presenting a significant delay in care.

These findings are consistent with the existing, limited epidemiological studies on trauma and support the need for early bystander intervention. The National Academies of Sciences (NASEM; Washington, DC USA) estimated that 20% of trauma-related deaths may have been preventable with receipt of “optimal trauma care” and noted that the “greatest opportunity to save lives” is in the prehospital setting. ^{Reference Berwick, Downey and Cornett12} In a recent analysis of 1,848 trauma-related deaths, Kalkwarf, et al found that 305 were due to uncontrolled hemorrhage. ^{Reference Kalkwarf, Drake and Yang13} They further reported that 45% of deaths (n = 137) were preventable or potentially preventable, with 35% of these deaths occurring in the prehospital setting. ^{Reference Kalkwarf, Drake and Yang13} In a separate investigation of the same data set, other investigators reported that among 847 prehospital deaths, 89 may have been prevented, and of these, 55% were due to hemorrhage. ^{Reference Drake, Holcomb and Yang14}

Patients with life-threatening hemorrhage may lose their entire circulating blood volume in under five minutes, ^{Reference Tjardes and Luecking15} making immediate intervention crucial to their survival. While injuries to the abdomen and chest generally require surgical intervention to control bleeding, limb/extremity wounds and those to other areas of the body may benefit from bystander intervention such as that taught in the STB courses. ^{Reference Eastridge, Holcomb and Shackelford2,16} Despite its simplicity and wide-spread applicability, STB training is still in its infancy and remains largely unknown to the lay public. To put this in perspective, the American Heart Association alone trains more than 22 million people globally in CPR each year. ⁹ Findings from an analysis of 110,054 witnessed out-of-hospital cardiac arrests highlight the substantial effect of bystander intervention, as 47% of those who provided CPR were laypersons. ^{Reference Garcia, Spertus and Girotra17} Further, investigators of a recent systematic review including 19 studies and more than 230,000 patients found that patients with witnessed out-of-hospital cardiac arrests who received bystander CPR were nearly two-times more likely to survive compared to those who did not receive bystander CPR (pooled odds ratio 1.95, 95% confidence interval [CI]: 1.66–2.30). ^{Reference Song, Guo, Lu, Kang, Song and Gong18} In contrast, less than 2.5 million people world-wide have ever received STB training. ¹⁹ This disparity in emergency response trainings presents a significant opportunity to reduce mortality and improve outcomes following major trauma and unintentional injury.

Though refresher training is required every two years to maintain CPR certification, ²⁰ no recommendations or requirements for STB skill maintenance currently exist. Recent evidence suggests that average rates of correct tourniquet application fall from 100% after initial training to 69% only six months after training (P <.001); however, only 46 participants were included in the study. ^{Reference Weinman21} Similarly, Goralnick, et al conducted a randomized clinical trial among laypersons (n = 465) to test the effectiveness of instructional point-of-care interventions and in-person training for hemorrhage control training compared to no intervention. ^{Reference Goralnick, Chaudhary and McCarty22} At three-to-nine months after training, investigators assessed the retention of skills for 303 participants and found that 54.5% could correctly apply a tourniquet. ^{Reference Goralnick, Chaudhary and McCarty22} Though striking, these findings represent small samples and additional research is required to further examine retention rates and factors associated with increased skill retention.

Feedback from STB participants across multiple studies indicate an appreciation of the significance of bleeding control training, confidence in the ability to intervene when necessary and willingness to do so, and the desire for regular refresher training. ^{Reference Nanassy, Graf and Budziszewski23–Reference Jones, Strickland and Brown26} Despite good intentions and willingness to help those injured, barriers to the provision of bleeding control aid in the prehospital setting exist among the lay community and may include: lack of access to supplies such as tourniquets and hemostatic gauze to effectively stop bleeding, fear of disease transmission on the part of the bystander without the use of gloves, fear of inflicting additional pain, fear of being sued by the injured person, concern for lack of physical ability to completely stop active bleeding, and fear of wound contamination or additional tissue damage with tourniquet application. ^{Reference Bouland, Halliday, Comer, Levy, Seaman and Lawner27} Importantly, the extent to which these or any additional barriers may exist, how they may most effectively be addressed, and the impact they have on bystander intervention have yet to be fully elucidated.