Does increased prehospital time lead to a “trial of life” effect for patients with blunt trauma?

Prehospital time and mortality in pediatric trauma

PURPOSE

The "Golden Hour" of transportation to a hospital has long been accepted as a central principal of trauma care. However, this has not been studied in pediatric populations. We assessed for non-linearity of the relationship between prehospital time and mortality in pediatric trauma patients, redefining the threshold at which reducing this time led to more favorable outcomes.

METHODS

We performed an analysis of the 2017-2018 American College of Surgeons Trauma Quality Improvement Program, including trauma patients age < 18 years. We examined the association between prehospital time and odds of in-hospital mortality using linear, polynomial, and restricted cubic spline (RCS) models, ultimately selecting the non-linear RCS model as the best fit.

RESULTS

60,670 patients were included in the study, of whom 1525 died and 3074 experienced complications. Prolonged prehospital time was associated with lower mortality and fewer complications. Both models demonstrated that mortality risk was lowest at 45-60 min, after which time was no longer associated with reduced probability of mortality.

CONCLUSIONS

The demonstration of a non-linear relationship between pre-hospital time and patient mortality is a novel finding. We highlight the need to improve prehospital treatment and access to pediatric trauma centers while aiming for hospital transportation within 45 min.

Numerical Simulation Study on Relationship between the Fracture Mechanisms and Residual Membrane Stresses of Metallic Material

The distribution and dissipation energies in fracture mechanisms were a critical challenge to derive, especially for this ultra-thin sample. The membrane failure, which is the end of the fracture mechanisms, is a result of the cone wave reflections from the backend membrane boundaries. These reflections delay the failure processes due to the shock impacts. To compare these results with the experimental work, a numerical simulation was conducted for these processes. The cylinder-shaped rigid projectile was impacted using a frictionless Lagrange solver. The target was a cartridge brass circle plate clamped at its perimeter, and its zone was refined to a ten-times higher meshing density for better analysis. The erosion and cut-off controls involved a zero-gap interaction condition and an instantaneous geometric erosion strain of 200%. Due to the maximum projectile velocity of 382 m/s having the slowest perforation, the target thickness was found to be 5.5 mm. The fracture mechanism phenomena, such as tensile, compressive, through-thickness, and growth in-plane delamination, propagating delamination, and local punch shear waves were observed. After deducting tensile and flexural strengths from the last experiment, a total residual membrane stress of 650 MPa was found. This result indicated a relationship between the fracture mechanisms and residual membrane stresses of metallic material.

Relationship Between Prehospital Time and 24-h Mortality in Road Traffic-Injured Patients in Laos

Background

Road traffic injury has long been regarded as a “time-dependent disease.” However, shortening the prehospital time might not improve the outcome in developing countries given the current quality of in-hospital care. We aimed to examine the relationship between the prehospital time and 24-h mortality among road traffic victims in Laos.

Methods

A prospective observational study was conducted using the trauma registry data on traffic-injured patients who were transported by ambulance to a trauma center in the capital city of Laos from May 2018 to April 2019. The analysis focused on patients with non-mild conditions, whose outcomes could be affected by the prehospital time. To examine the relationship between a prehospital time of <60 min and 24-h mortality, a generalized estimating equation model was used incorporating the inverse probability weights utilizing the propensity score for the prehospital time.

Results

Of 701 patients, 73% were men, 91% were riding 2- or 3-wheel motor vehicles during the crash, and 68% had a prehospital time of <60 min. A total of 35 patients died within 24 h after the crash. Compared with those who survived, individuals who died tended to have head and torso injuries. The proportions of 24-h mortality were 4.7% and 5.4% in patients whose prehospital time was <60 min and ≥60 min, respectively. No significant relationship was found between the prehospital time and 24-h mortality.

Conclusion

A shorter prehospital time was not associated with the 24-h survival among road traffic victims in Laos.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00268-022-06445-9.

Prolonged Prehospital Time is a Risk Factor for Pneumonia in Trauma (the PRE-TRIP study): A Retrospective Analysis of the United States National Trauma Data Bank

BACKGROUND

Although multiple risk factors for development of pneumonia in patients with trauma sustained in a motor vehicle accident have been studied, the effect of prehospital time on pneumonia incidence post-trauma is unknown.

RESEARCH QUESTION

Is prolonged prehospital time an independent risk factor for pneumonia?

STUDY DESIGN AND METHODS

We retrospectively analyzed prospectively collected clinical data from 806,012 motor vehicle accident trauma incidents from the roughly 750 trauma hospitals contributing data to the National Trauma Data Bank between 2010 and 2016.

RESULTS

Prehospital time was independently associated with development of pneumonia post-motor vehicle trauma (p < 0.001). This association was primarily driven by patients with low Glasgow Coma Scale scores. Post-trauma pneumonia was uncommon (1.5% incidence) but was associated with a significant increase in mortality (p < 0.001, 4.3% mortality without pneumonia vs. 12.1% mortality with pneumonia). Other pneumonia risk factors included age, sex, race, primary payor, trauma center teaching status, bed size, geographic region, intoxication, comorbid lung disease, steroid use, lower Glasgow Coma Scale score, higher Injury Severity Scale score, blood product transfusion, chest trauma, and respiratory burns.

INTERPRETATION

Increased prehospital time is an independent risk factor for development of pneumonia and increased mortality in patients with trauma caused by a motor vehicle accident. Although prehospital time is often not modifiable, its recognition as a pneumonia risk factor is important as prolonged prehospital time may need to be considered in subsequent decision making.

CLINICAL TRIAL REGISTRATION

Not applicable.

Association between Mode of Transportation and Survival in Adult Trauma Patients with Blunt Injuries: Matched Cohort Study between Police and Ground Ambulance Transport

INTRODUCTION

Early police transport (PT) of penetrating trauma patients has the potential to improve survival rates for trauma patients. There are no well-established guidelines for the transport of blunt trauma patients by PT currently.

STUDY OBJECTIVE

This study examines the association between the survival rate of blunt trauma patients and the transport modality (police versus ground ambulance).

METHODS

A retrospective, matched cohort study was conducted using the National Trauma Data Bank (NTDB). All blunt trauma patients transported by police to trauma centers were identified and matched (one-to-four) to patients transported by ground Emergency Medical Services (EMS) for analysis. Descriptive analysis was carried out. This was followed by comparing all patients' characteristics and their survival rates in terms of the mode of transportation.

RESULTS

Out of the 2,469 patients with blunt injuries, EMS transported 1,846 patients and police transported 623 patients. Most patients were 16-64 years of age (86.2%) with a male predominance (82.5%). Fall (38.4%) was the most common mechanism of injury with majority of injuries involving the head and neck body part (64.8%). Fractures were the most common nature of injury (62.1%). The overall survival rate of adult blunt trauma patients was similar for both methods of transportation (99.2%; P = 1.000).

CONCLUSION

In this study, adult blunt trauma patients transported by police had similar outcomes to those transported by EMS. As such, PT in trauma should be encouraged and protocolized to improve resource utilization and outcomes further.

A scoping review of worldwide studies evaluating the effects of prehospital time on trauma outcomes

BACKGROUND

Annually, over 1 billion people sustain traumatic injuries, resulting in over 900,000 deaths in Africa and 6 million deaths globally. Timely response, intervention, and transportation in the prehospital setting reduce morbidity and mortality of trauma victims. Our objective was to describe the existing literature evaluating trauma morbidity and mortality outcomes as a function of prehospital care time to identify gaps in literature and inform future investigation.

MAIN BODY

We performed a scoping review of published literature in MEDLINE. Results were limited to English language publications from 2009 to 2020. Included articles reported trauma outcomes and prehospital time. We excluded case reports, reviews, systematic reviews, meta-analyses, comments, editorials, letters, and conference proceedings. In total, 808 articles were identified for title and abstract review. Of those, 96 articles met all inclusion criteria and were fully reviewed. Higher quality studies used data derived from trauma registries. There was a paucity of literature from studies in low- and middle-income countries (LMIC), with only 3 (3%) of articles explicitly including African populations. Mortality was an outcome measure in 93% of articles, predominantly defined as "in-hospital mortality" as opposed to mortality within a specified time frame. Prehospital time was most commonly assessed as crude time from EMS dispatch to arrival at a tertiary trauma center. Few studies evaluated physiologic morbidity outcomes such as multi-organ failure.

CONCLUSION

The existing literature disproportionately represents high-income settings and most commonly assessed in-hospital mortality as a function of crude prehospital time. Future studies should focus on how specific prehospital intervals impact morbidity outcomes (e.g., organ failure) and mortality at earlier time points (e.g., 3 or 7 days) to better reflect the effect of early prehospital resuscitation and transport. Trauma registries may be a tool to facilitate such research and may promote higher quality investigations in Africa and LMICs.

Clinical guided computer tomography decisions are advocated in potentially severely injured trauma patients: a one-year audit in a level 1 trauma Centre with long pre-hospital times

BACKGROUND

The International Commission on Radiological Protection's (ICRP) justification principles state that an examination is justified if the potential benefit outweighs the risk for radiation harm. Computer tomography (CT) contributes 50% of the radiation dose from medical imaging, and in trauma patients, the use of standardized whole body CT (SWBCT) increases. Guidelines are lacking, and reviews conclude conflictingly regarding the benefit. We aimed to study the degree of adherence to ICRP's level three justification, the individual dose limitation principle, in our institution.

METHODS

This is a retrospective clinical audit. We included all 144 patients admitted with trauma team activation to our regional Level 1 trauma centre in 2015. Injuries were categorized according to the Abbreviated Injury Scale (AIS) codes. Time variables, vital parameters and interventions were registered. We categorized patients into trauma admission SWBCT, selective CT or no CT examination strategy groups. We used descriptive statistics and regression analysis of predictors for CT examination strategy.

RESULTS

The 144 patients (114 (79.2%) males) had a median age of 31 (range 0-91) years. 105 (72.9%) had at least one AIS ≥ 2 injury, 26 (18.1%) in more than two body regions. During trauma admission, at least one vital parameter was abnormal in 46 (32.4%) patients, and 73 (50.7%) underwent SWBCT, 43 (29.9%) selective CT and 28 (19.4%) no CT examination. No or only minor injuries were identified in 17 (23.3%) in the SWBCT group. Two (4.6%) in the selective group were examined with a complement CT, with no new injuries identified. A significantly (p < 0.001) lower proportion of children (61.5%) than adults (89.8%) underwent CT examination despite similar injury grades and use of interventions. In adjusted regression analysis, patients with a high-energy trauma mechanism had significantly (p = 0.028) increased odds (odds ratio = 4.390, 95% confidence interval 1.174-16.413) for undergoing a SWBCT.

CONCLUSION

The high proportion of patients with no or only minor injuries detected in the SWBCT group and the significantly lower use of CT among children, indicate that use of a selective CT examination strategy in a higher proportion of our patients would have approximated the ICRP's justification level three, the individual dose limitation principle, better.

Effect of predicted travel time to trauma care on mortality in major trauma patients in Nova Scotia

Background

Trauma is a leading contributor to the burden of disease in Canada, accounting for more than 15 000 deaths annually. Although caring for injured patients at designated trauma centres (TCs) is consistently associated with survival benefits, it is unclear how travel time to definitive care influences outcomes. Using a population-based sample of trauma patients, we studied the association between predicted travel time (PTT) to TCs and mortality for patients assigned to ground transport.

Methods

Victims of penetrating trauma or motor vehicle collisions (MVCs) in Nova Scotia between 2005 and 2014 were identified from a provincial trauma registry. We conducted cost distance analyses to quantify PTT for each injury location to the nearest TC. Adjusted associations between TC access and injury-related mortality were then estimated using logistic regression.

Results

Greater than 30 minutes of PTT to a TC was associated with a 66% increased risk of death for MVC victims (p = 0.045). This association was lost when scene deaths were excluded from the analysis. Sustaining a penetrating trauma greater than 30 minutes from a TC was associated with a 3.4-fold increase in risk of death. Following the exclusion of scene deaths, this association remained and approached significance (odds ratio 3.48, 95% confidence interval 0.98–14.5, p = 0.053).

Conclusion

Predicted travel times greater than 30 minutes were associated with worse outcomes for victims of MVCs and penetrating injuries. Improving communication across the trauma system and reducing prehospital times may help optimize outcomes for rural trauma patients.

A comparison of major trauma patient transport destination in metropolitan Perth, Western Australia

BACKGROUND

Despite evidence of a lower risk of death, major trauma patients are not always transported to Trauma Centres. This study examines the characteristics and outcomes of major trauma patients between transport destinations.

METHODS

A retrospective cohort study of major trauma patients (Injury Severity Score >15) transported by ambulance was undertaken. Cases were divided into transport destination groups: (1) Direct, those transported to the Trauma Centre directly from the scene; (2) Indirect, those transported to another hospital prior to Trauma Centre transfer and (3) Non-transfers, those transported to a non-Trauma Centre and never subsequently transferred. Median and interquartile range (IQR) were used to describe the groups and differences were assessed using the Kruskal-Wallis test for continuous variables and Pearson chi-square for categorical.

RESULTS

A total of 1625 patients were included. The median age was oldest in the non-transfers cohort (72 years IQR 46-84). This group had the highest proportion of falls from standing and head injuries (n = 298/400, 75%, p < 0.001). The non-transfers had the highest proportion of 30-day mortality (n = 134/400, 34%).

CONCLUSIONS

There were significant differences between the groups with older adults, falls and head injuries over-represented in the non-transfer group. Considering the ageing population, trauma systems will need to adapt.

Longer Prehospital Time was not Associated with Mortality in Major Trauma: A Retrospective Cohort Study

Objective: The objective of this study was to determine the association between prehospital time and outcomes in adult major trauma patients, transported by ambulance paramedics. Methods: A retrospective cohort study of major trauma patients (Injury Severity Score >15) attended by St John Ambulance paramedics in Perth, Western Australia, who were transported to hospital between January 1, 2013 and December 31, 2016. Inverse probability of treatment weighting (IPTW) using the propensity score was performed to limit selection bias and confounding. The primary outcome was 30-day mortality and the secondary outcome was the length of hospital stay (LOS) for 30-day survivors. Multivariate logistic and log-linear regression analyses with IPTW were used to determine if prehospital time of more than the one hour (from receipt of the emergency call to arrival at hospital) or any individual prehospital time interval (response, on-scene, transport, or total time) was associated with 30-day mortality or LOS. Results: A total of 1,625 major trauma patients were included and 1,553 included in the IPTW sample. No significant association between prehospital time of one hour and 30-day mortality was found (adjusted odds ratio 1.10, 95% confidence interval (CI) 0.71-1.69). No association between any individual prehospital time interval and 30-day mortality was identified. In the 30-day survivors, one-minute increase of on-scene time was associated with 1.16 times (95% CI 1.03-1.31) longer LOS. Conclusion: Longer prehospital times were not associated with an increased likelihood of 30-day mortality in major trauma patients transported to hospital by ambulance paramedics. We found no evidence to support the hypothesis that prehospital time longer than one hour resulted in an increased risk of 30-day mortality. However, longer on-scene time was associated with longer hospital LOS (for 30-day survivors). Our recommendation is that prehospital care is delivered in a timely fashion and delivery of the patient to hospital is reasonably prompt.