The role of timely emergency care for hypotensive trauma patients
Meizoso et al.1 published thoughtful analysis investigating the effect of time to operation on mortality for hypotensive patients with gunshot wounds (GSW) to the torso. The authors hypothesized and concluded that a delay of more than 10 minutes to the emergency department room results in poorer outcomes in GSW patients. However, the study fails to address its numerous underlying caveats.
First, the retrospective nature of this study has several inherent limitations, of which the most significant is the relatively large margin for selection bias. This is because the baseline patient characteristics, specifically those that can affect the outcomes of trauma, have not been matched between the cohorts. Furthermore, factors such as age, gender, and other comorbidities that are well known to impact the underlying physiological responses to trauma are not accounted for in this study. It is perhaps misleading that time to operating room (OR) focuses on the duration after admission only and ignores the time to hospital admission. A prolonged time to hospital admission will worsen the outcomes—another baseline characteristic that must have been matched. In their analysis, the authors have compared baseline characteristics between survivors and nonsurvivors, instead of a stratified analysis based on timing to the OR, and such an approach does not justify the aims of the article. Another major confounder that was not accounted for is how busy the OR was at the time. Even at a Level I trauma center where this study was performed, the frequency of admissions will fluctuate, and with it the allocation of resources for each patient. Factors such as the expertise of attending physicians or their level of attentiveness are affected by their workload.2 Although this cannot be controlled for, it is a caveat that must be noted when interpreting the results, but the authors make no mention of this at all.
Furthermore, the authors have chosen an arbitrary duration of 10 minutes to the OR as the cutoff with no justification for this value, especially because the literature cited by them does not propose this cutoff either.3 In this study, only 28% of the patients achieved this target, reflecting how unfeasible it is in reality, even in an emergency setting. This can be partly attributed to the numerous protocols patients undergo so that the final stage of care is tailored toward their individual pathology. This is in contrast to and more beneficial than bringing every patient to the OR within 10 minutes.
Some features of the study may also overestimate its outcomes. First, the primary outcome is all-cause mortality, even though the study specifically focuses on reducing the second peak of Trunkey’s trimodal distribution by reducing hemorrhage and managing hypotension.4 Furthermore, a systolic blood pressure (SBP) of less than 110 mm Hg was used to define hypotension in this study. This value is unconventional, with no justification provided from the authors. Previous work and standard trauma care identifies hypotension as SBP below 90 mm Hg, so including patients who will otherwise be classified as normotensive is misleading in estimating the true effect. Furthermore, only 24% of the patients had SBP below 70 mm Hg, and it is unclear what proportion arrived at OR within 10 minutes. Lastly, the inclusion criteria are biased against patients who might have poorer outcomes, including those requiring resuscitative thoracotomy, having traumatic brain injury, and undergoing surgery for more than 1 hour. Further compounding this is the lack of matching of Injury Severity Scores or Abbreviated Injury Scale Score between the cohorts. As a single-center study, the high level of expertise in a Level I trauma center cannot be expected elsewhere either.