Early and prehospital trauma deaths: Who might benefit from advanced resuscitative care?

Prehospital Partial Resuscitative Endovascular Balloon Occlusion of the Aorta for Exsanguinating Subdiaphragmatic Hemorrhage

Importance

Hemorrhage is the most common cause of preventable death after injury. Most deaths occur early, in the prehospital phase of care.

Objective

To establish whether prehospital zone 1 (supraceliac) partial resuscitative endovascular balloon occlusion of the aorta (Z1 P-REBOA) can be achieved in the resuscitation of adult trauma patients at risk of cardiac arrest and death due to exsanguination.

Design, Setting, and Participants

This was a prospective observational cohort study (Idea, Development, Exploration, Assessment and Long-term follow-up [IDEAL] 2A design) with recruitment from June 2020 to March 2022 and follow-up until discharge from hospital, death, or 90 days evaluating a physician-led and physician-delivered, urban prehospital trauma service in the Greater London area. Trauma patients aged 16 years and older with suspected exsanguinating subdiaphragmatic hemorrhage, recent or imminent hypovolemic traumatic cardiac arrest (TCA) were included. Those with unsurvivable injuries or who were pregnant were excluded. Of 2960 individuals attended by the service during the study period, 16 were included in the study.

Exposures

ZI REBOA or P-REBOA.

Main Outcomes and Measures

The main outcome was the proportion of patients in whom Z1 REBOA and Z1 P-REBOA were achieved. Clinical end points included systolic blood pressure (SBP) response to Z1 REBOA, mortality rate (1 hour, 3 hours, 24 hours, or 30 days postinjury), and survival to hospital discharge.

Results

Femoral arterial access for Z1 REBOA was attempted in 16 patients (median [range] age, 30 [17-76] years; 14 [81%] male; median [IQR] Injury Severity Score, 50 [39-57]). In 2 patients with successful arterial access, REBOA was not attempted due to improvement in clinical condition. In the other 14 patients (8 [57%] of whom were in traumatic cardiac arrest [TCA]), 11 successfully underwent cannulation and had aortic balloons inflated in Z1. The 3 individuals in whom cannulation was unsuccessful were in TCA (failure rate = 3/14 [21%]). Median (IQR) pre-REBOA SBP in the 11 individuals for whom cannulation was successful (5 [46%] in TCA) was 47 (33-52) mm Hg. Z1 REBOA plus P-REBOA was associated with a significant improvement in BP (median [IQR] SBP at emergency department arrival, 101 [77-107] mm Hg; 0 of 10 patients were in TCA at arrival). The median group-level improvement in SBP from the pre-REBOA value was 52 (95% CI, 42-77) mm Hg (P < .004). P-REBOA was feasible in 8 individuals (8/11 [73%]) and occurred spontaneously in 4 of these. The 1- and 3-hour postinjury mortality rate was 9% (1/11), 24-hour mortality was 27% (3/11), and 30-day mortality was 82% (9/11). Survival to hospital discharge was 18% (2/11). Both survivors underwent early Z1 P-REBOA.

Conclusions and Relevance

In this study, prehospital Z1 P-REBOA is feasible and may enable early survival, but with a significant incidence of late death.

Trial Registration

ClinicalTrials.gov Identifier: NCT04145271.

Witnessed prehospital traumatic arrest: predictors of survival to hospital discharge

PURPOSE

Trauma patients are rapidly transported to the hospital for definitive care. Nonetheless, some are alive upon Emergency Medical Services (EMS) arrival but arrest on-scene or during transport. The study objective was to examine EMS-witnessed traumatic arrests to define patients who survived hospital discharge.

METHODS

Patients sustaining EMS-witnessed traumatic arrest and entered into the National Trauma Data Bank were included (2007-2018). Mortality defined groups: survival to hospital discharge vs. in-hospital death vs. death in ED/declared dead on arrival (DOA). ANOVA/Chi-square compared cohorts. Multivariable analysis established factors associated with survival out of ED and to hospital discharge.

RESULTS

After exclusions, 14,177 patients met the criteria: 10% survived, 22% died in hospital, and 68% died in ED/DOA. Survivors tended to be female (33% vs. 23% vs. 23%, p < 0.001), blunt traumas (71% vs. 56% vs. 60%, p < 0.001), have higher scene GCS (15 [7-15] vs. 3 [3-11] vs. 3 [3-7], p < 0.001), and lower injury severity (ISS 13 [7-26] vs. 27 [18-41] vs. 25 [10-30], p < 0.001), particularly of the head (AIS 0 [0-2] vs. 0 [0-4] vs. 1 [0-4], p < 0.001). Survival to hospital discharge was independently associated with higher field GCS (OR 1.252, p < 0.001) and SBP (OR 1.006, p < 0.001), and Head AIS scores (OR 1.073, p < 0.001). Increasing age (OR 0.984, p < 0.001), higher ISS (OR 0.975, p < 0.001), male sex (OR 0.695, p < 0.001), and penetrating mechanism of injury (OR 0.537, p < 0.001) were associated with reduced survival to discharge.

CONCLUSION

After EMS-witnessed traumatic cardiac arrest, survivors were more likely to be young, female, injured by blunt trauma, and less hypotensive/comatose on-scene. These findings may have implications for ED resuscitation or declaration of care futility and should be further investigated with a prospective multicenter study.

Association between out-of-hospital cardiac arrest quality indicator and prehospital management and clinical outcomes for major trauma

INTRODUCTION

It is unclear whether emergency medical service (EMS) agencies with good out-of-hospital cardiac arrest (OHCA) quality indicators also perform well in treating other emergency conditions. We aimed to evaluate the association of an EMS agency's non-traumatic OHCA quality indicators with prehospital management processes and clinical outcomes of major trauma.

METHODS

This retrospective cross-sectional study analyzed data from registers of nationwide, population-based OHCA (adult EMS-treated non-traumatic OHCA patients from 2017 to 2018) and major trauma (adult, EMS-treated, and injury severity score ≥16 trauma patients in 2018) in South Korea. We developed a prehospital ROSC prediction model to categorize EMS agencies into quartiles (Q1-Q4) based on the observed-to-expected (O/E) ROSC ratio for each EMS agency. We evaluated the national EMS protocol compliance of on-scene management according to O/E ROSC ratio quartile. The association between O/E ROSC ratio quartiles and trauma-related early mortality was determined in a multi-level logistic regression model by adjusted odds ratios (OR) and 95 % confidence intervals (95 % CI).

RESULTS

Among 30,034 severe trauma patients, 4,836 were analyzed. Patients in Q4 showed the lowest early mortality rate (5.6 %, 5.5 %, 4.8 %, and 3.4 % in Q1, Q2, Q3, and Q4, respectively). In groups Q1 to Q4, increasing compliance with the national EMS on-scene management protocol (trauma center transport, basic airway management for patients with altered mentality, spinal motion restriction for patients with spinal injury, and intravenous access for patients with hypotension) was observed (p for trend <0.05). Multivariable multi-level logistic regression analysis showed significantly lower early mortality in Q4 than in Q1 (adjusted OR [95 % CI] 0.56 [0.35-0.91]).

CONCLUSION

Major trauma patients managed by EMS agencies with high success rates in achieving prehospital ROSC in non-traumatic OHCA were more likely to receive protocol-based care and exhibited lower early mortality.

Safety of the injectable expanding biopolymer foam for non-compressible truncal bleeding in swine

BACKGROUND

A novel hydrophobically modified chitosan (hm-chitosan) polymer has been previously shown to improve survival in a non-compressible intra-abdominal bleeding model in swine. We performed a 28-day survival study to evaluate the safety of the hm-chitosan polymer in swine.

METHODS

Female Yorkshire swine (40-50 kg) were used. A mild, non-compressible, closed-cavity bleeding model was created with splenic transection. The hm-chitosan polymer was applied intra-abdominally through an umbilical nozzle in the same composition and dose previously shown to improve survival. Animals were monitored intraoperatively and followed 28 days postoperatively for survival, signs of pain, and end-organ function. Gross pathological and microscopic evaluations were performed at the conclusion of the experiment.

RESULTS

A total of 10 animals were included (hm-chitosan = 8; control = 2). The 2 control animals survived through 28 days, and 7 of the 8 animals from the hm-chitosan group survived without any adverse events. One animal from the hm-chitosan group required early termination of the study for signs of pain, and superficial colonic ulcers were found on autopsy. Laboratory tests showed no signs of end-organ dysfunction after exposure to hm-chitosan after 28 days. On gross pathological examination, small (<0.5 cm) peritoneal nodules were noticed in the hm-chitosan group, which were consistent with giant-cell foreign body reaction in microscopy, presumably related to polymer remnants. Microscopically, no signs of systemic polymer embolization or thrombosis were noticed.

CONCLUSION

Prolonged intraperitoneal exposure to the hm-chitosan polymer was tolerated without any adverse event in the majority of animals. In the single animal that required early termination, the material did not appear to be associated with end-organ dysfunction in swine. Superficial colonic ulcers that would require surgical repair were identified in 1 out of 8 animals exposed to hm-chitosan.

TiME OUT: Time-specific machine-learning evaluation to optimize ultramassive transfusion

BACKGROUND

Ultramassive transfusion (UMT) is a resource-demanding intervention for trauma patients in hemorrhagic shock, and associated mortality rates remains high. Current research has been unable to identify a transfusion ceiling or point where UMT transitions from lifesaving to futility. Furthermore, little consideration has been given to how time-specific patient data points impact decisions with ongoing high-volume resuscitation. Therefore, this study sought to use time-specific machine learning modeling to predict mortality and identify parameters associated with survivability in trauma patients undergoing UMT.

METHODS

A retrospective review was conducted at a Level I trauma (2018-2021) and included trauma patients meeting criteria for UMT, defined as ≥20 red blood cell products within 24 hours of admission. Cross-sectional data were obtained from the blood bank and trauma registries, and time-specific data were obtained from the electronic medical record. Time-specific decision-tree models predicating mortality were generated and evaluated using area under the curve.

RESULTS

In the 180 patients included, mortality rate was 40.5% at 48 hours and 52.2% overall. The deceased received significantly more blood products with a median of 71.5 total units compared with 55.5 in the survivors ( p < 0.001) and significantly greater rates of packed red blood cells and fresh frozen plasma at each time interval. Time-specific decision-tree models predicted mortality with an accuracy as high as 81%. In the early time intervals, hemodynamic stability, undergoing an emergency department thoracotomy, and injury severity were most predictive of survival, while, in the later intervals, markers of adequate resuscitation such as arterial pH and lactate level became more prominent.

CONCLUSION

This study supports that the decision of "when to stop" in UMT resuscitation is not based exclusively on the number of units transfused but rather the complex integration of patient and time-specific data. Machine learning is an effective tool to investigate this concept, and further research is needed to refine and validate these time-specific decision-tree models.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Revisiting the promise, practice and progress of resuscitative endovascular balloon occlusion of the aorta

PURPOSE OF REVIEW

The use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) to temporarily control bleeding and improve central perfusion in critically injured trauma patients remains a controversial topic. In the last decade, select trauma services around the world have gained experience with REBOA. We discuss the recent observational data together with the initial results of the first randomized control trial and provide a view on the next steps for REBOA in trauma resuscitation.

RECENT FINDINGS

While the observational data continue to be conflicting, the first randomized control trial signals that in the UK, in-hospital REBOA is associated with harm. Likely a result of delays to haemorrhage control, views are again split on whether to abandon complex interventions in bleeding trauma patients and to only prioritize transfer to the operating room or to push REBOA earlier into the post injury phase, recognizing that some patients will not survive without intervention.

SUMMARY

Better understanding of cardiac shock physiology provides a new lens in which to evaluate REBOA through. Patient selection remains a huge challenge. Invasive blood pressure monitoring, combined with machine learning aided decision support may assist clinicians and their patients in the future. The use of REBOA should not delay definitive haemorrhage control in those patients without impending cardiac arrest.

Prehospital blood transfusion in Brazil: results of the first year of implementation in an emergency medical service

INTRODUCTION

Hemorrhagic shock is the main cause of death in the prehospital environment, which highlights the need to standardize measures aiming at bleeding control and volume replacement in this environment. In Brazil, the first prehospital packed red blood cell transfusion service started in September 2020, in Bragança Paulista, state of São Paulo.

OBJECTIVES

Describe the trends and characteristics of patients who received prehospital transfusions prior to hospital treatment during the first year of operation.

METHODS

A retrospective data review was made of all patients who received transfusions from the mobile intensive care unit in Bragança Paulista over one year.

RESULTS

In this period, 19 patients were transfused. Since activation, the average response time was 20 min. The mean shock indexes before and after blood transfusion were 2.16 and 1.1, respectively. During the course of the 1st year of prehospital transfusions, no blood was wasted and there were no adverse effects.

CONCLUSION

Introduction of the prehospital packed red blood cell transfusion service was successful, with significant improvement in hemodynamic parameters.

Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.

Characterization of cerebral blood flow during open cardiac massage in swine: Effect of volume status

Introduction: Patients in cardiac arrest treated with resuscitative thoracotomy and open cardiac massage (OCM) have high rates of mortality with poor neurological outcomes. The aim of this study is to quantitate cerebral perfusion during OCM using computed tomography perfusion (CTP) imaging in a swine model of normo- and hypovolemia.

Methods: Anesthetized swine underwent instrumentation with right atrial and aortic pressure catheters. A catheter placed in the ascending aorta was used to administer iodinated contrast and CTP imaging acquired. Cerebral blood flow (CBF; ml/100 g of brain) and time to peak (TTP; s) were measured. Animals were then euthanized by exsanguination (hypovolemic group) or potassium chloride injection (normovolemic group) and subjected to a clamshell thoracotomy, aortic cross clamping, OCM, and repeated CTP. Data pertaining to peak coronary perfusion pressure (pCoPP; mmHg) were collected and % CoPP > 15 mmHg (% CoPP; s) calculated post hoc.

Results: Normovolemic animals (n = 5) achieved superior pCoPP compared to the hypovolemic animals (n = 5) pCoPP (39.3 vs. 12.3, p < 0.001) and % CoPP (14.5 ± 1.9 vs. 30.9 ± 6.5, p < 0.001). CTP acquisition was successful and TTP elongated from spontaneous circulation, normovolemia to hypovolemia (5.7 vs. 10.8 vs. 14.8, p = 0.01). CBF during OCM was similar between hypovolemic and normovolemic groups (7.5 ± 8.1 vs. 4.9 ± 6.0, p = 0.73) which was significantly lower than baseline values (51.9 ± 12.1, p < 0.001).

Conclusion: OCM in normovolemia generates superior coronary hemodynamics compared to hypovolemia. Despite this, neither generates adequate CBF as measured by CTP, compared to baseline. To improve the rate of neurologically intact survivors, novel resuscitative techniques need to be investigated that specifically target cerebral perfusion as existing techniques are inadequate.

Novel Prehospital Phenotypes and Outcomes in Adult-Patients with Acute Disease

An early identification of prehospital phenotypes may allow health care workers to speed up and improve patients’ treatment. To determine emergency phenotypes by exclusively using prehospital clinical data, a multicenter, prospective, and observational ambulance-based study was conducted with a cohort of 3,853 adult patients treated consecutively and transferred with high priority from the scene to the hospital emergency department. Cluster analysis determined three clusters with highly different outcome scores and pathological characteristics. The first cluster presented a 30-day mortality after the index event of 45.9%. The second cluster presented a mortality of 26.3%, while mortality of the third cluster was 5.1%. This study supports the detection of three phenotypes with different risk stages and with different clinical, therapeutic, and prognostic considerations. This evidence could allow adapting treatment to each phenotype thereby helping in the decision-making process.

Impact of time to surgery on mortality in hypotensive patients with noncompressible torso hemorrhage: An AAST multicenter, prospective study

BACKGROUND

Death from noncompressible torso hemorrhage (NCTH) may be preventable with improved prehospital care and shorter in-hospital times to hemorrhage control. We hypothesized that shorter times to surgical intervention for hemorrhage control would decrease mortality in hypotensive patients with NCTH.

METHODS

This was an AAST-sponsored multicenter, prospective analysis of hypotensive patients aged 15+ years who presented with NCTH from May 2018 to December 2020. Hypotension was defined as an initial systolic blood pressure (SBP) ≤ 90 mm Hg. Primary outcomes of interest were time to surgical intervention and in-hospital mortality.

RESULTS

There were 242 hypotensive patients, of which 48 died (19.8%). Nonsurvivors had higher mean age (47.3 vs. 38.8; p = 0.02), higher mean New Injury Severity Score (38 vs. 29; p < 0.001), lower admit systolic blood pressure (68 vs. 79 mm Hg; p < 0.01), higher incidence of vascular injury (41.7% vs. 21.1%; p = 0.02), and shorter median (interquartile range, 25-75) time from injury to operating room start (74 minutes [48-98 minutes] vs. 88 minutes [61-128 minutes]; p = 0.03) than did survivors. Multivariable Cox regression showed shorter time from emergency department arrival to operating room start was not associated with improved survival (p = 0.04).

CONCLUSION

Patients who died arrived to a trauma center in a similar time frame as did survivors but presented in greater physiological distress and had significantly shorter times to surgical hemorrhage intervention than did survivors. This suggests that even expediting a critically ill patient through the current trauma system is not sufficient time to save lives from NCTH. Civilian prehospital advance resuscitative care starting from the patient first contact needs special consideration.

LEVEL OF EVIDENCE

Prognostic/Epidemiologic, Level III.

Factors Associated With Increased Mortality in Severe Abdominopelvic Injury

BACKGROUND

Associated injuries are thought to increase mortality in patients with severe abdominopelvic trauma. This study aimed to identify clinical factors contributing to increased mortality in patients with severe abdominopelvic trauma, with the hypothesis that a greater number of concomitant injuries would result in increased mortality.

METHODS

This was a retrospective review of the Trauma Quality Improvement Program (TQIP) database of patients ≥ 18 years with severe abdominopelvic trauma defined as having an abdominal Abbreviated Injury Score (AIS) ≥ 3 with pelvic fractures and/or iliac vessel injury (2015-2017). Primary outcome was in-hospital mortality based on concomitant body region injuries. Secondary outcomes included mortality at 6 h, 6 to 24 h, and after 24 h based on concomitant injuries, procedures performed, and transfusion requirements.

RESULTS

A total of 185,257 patients were included in this study. Survivors had more severely injured body regions than non-survivors (4 vs. 3, P < 0.001). Among those who died within 6 h, 28.5% of patients required a thoracic procedure and 43% required laparotomy compared to 6.3% and 22.1% among those who died after 24 h (P < 0.001). Head AIS ≥ 3 was the only body region that significantly contributed to overall mortality (OR 1.26, P < 0.001) along with laparotomy (OR 3.02, P < 0.001), neurosurgical procedures (2.82, P < 0.001) and thoracic procedures (2.28, P < 0.001). Non-survivors who died in < 6 h and 6-24 h had greater pRBC requirements than those who died after 24 h (15.5 and 19.5 vs. 8 units, P < 0.001).

CONCLUSION

Increased number of body regions injured does not contribute to greater mortality. Uncontrolled noncompressible torso hemorrhage rather than the burden of concomitant injuries is the major contributor to the high mortality associated with severe abdominopelvic injury.

Selective Prehospital Advanced Resuscitative Care - Developing a Strategy to Prevent Prehospital Deaths From Noncompressible Torso Hemorrhage

Hemorrhage, and particularly noncompressible torso hemorrhage remains a leading cause of potentially preventable prehospital death from trauma in the United States and globally. A subset of severely injured patients either die in the field or develop irreversible hemorrhagic shock before they can receive hospital definitive care, resulting in poor outcomes. The focus of this opinion paper is to delineate (a) the need for existing trauma systems to adapt so that potentially life-saving advanced resuscitation and truncal hemorrhage control interventions can be delivered closer to the point-of-injury in select patients, and (b) a possible mechanism through which some trauma systems can train and incorporate select prehospital advanced resuscitative care teams to deliver those interventions.

The Pathophysiology and Management of Hemorrhagic Shock in the Polytrauma Patient

The recognition and management of life-threatening hemorrhage in the polytrauma patient poses several challenges to prehospital rescue personnel and hospital providers. First, identification of acute blood loss and the magnitude of lost volume after torso injury may not be readily apparent in the field. Because of the expression of highly effective physiological mechanisms that compensate for a sudden decrease in circulatory volume, a polytrauma patient with a significant blood loss may appear normal during examination by first responders. Consequently, for every polytrauma victim with a significant mechanism of injury we assume substantial blood loss has occurred and life-threatening hemorrhage is progressing until we can prove the contrary. Second, a decision to begin damage control resuscitation (DCR), a costly, highly complex, and potentially dangerous intervention must often be reached with little time and without sufficient clinical information about the intended recipient. Whether to begin DCR in the prehospital phase remains controversial. Furthermore, DCR executed imperfectly has the potential to worsen serious derangements including acidosis, coagulopathy, and profound homeostatic imbalances that DCR is designed to correct. Additionally, transfusion of large amounts of homologous blood during DCR potentially disrupts immune and inflammatory systems, which may induce severe systemic autoinflammatory disease in the aftermath of DCR. Third, controversy remains over the composition of components that are transfused during DCR. For practical reasons, unmatched liquid plasma or freeze-dried plasma is transfused now more commonly than ABO-matched fresh frozen plasma. Low-titer type O whole blood may prove safer than red cell components, although maintaining an inventory of whole blood for possible massive transfusion during DCR creates significant challenges for blood banks. Lastly, as the primary principle of management of life-threatening hemorrhage is surgical or angiographic control of bleeding, DCR must not eclipse these definitive interventions.

Advanced prehospital resuscitative care: Can we identify trauma patients who might benefit?

BACKGROUND

Uncontrolled truncal hemorrhage remains the most common cause of potentially preventable death after injury. The notion of earlier hemorrhage control and blood product resuscitation is therefore attractive. Some systems have successfully implemented prehospital advanced resuscitative care (ARC) teams. Early identification of patients is key and is reliant on rapid decision making and communication. The purpose of this simulation study was to explore the feasibility of early identification of patients who might benefit from ARC in a typical US setting.

METHODS

We conducted a prospective observational/simulation study at a level I trauma center and two associated emergency medical service (EMS) agencies over a 9-month period. The participating EMS agencies were asked to identify actual patients who might benefit from the activation of a hypothetical trauma center-based ARC team. This decision was then communicated in real time to the study team.

RESULTS

Sixty-three patients were determined to require activation. The number of activations per month ranged from 2 to 15. The highest incidence of calls occurred between 4 pm to midnight. Of the 63 patients, 33 were transported to the trauma center. The most common presentation was with penetrating trauma. The median age was 27 years (interquartile range, 24-45 years), 75% were male, and the median Injury Severity Score was 11 (interquartile range, 7-20). Based on injury patterns, treatment received, and outcomes, it was determined that 6 (18%) of 33 patients might have benefited from ARC. Three of the patients died en-route to or soon after arrival at the trauma center.

CONCLUSION

The prehospital identification of patients who might benefit from ARC is possible but faces challenges. Identifying strategies to adapt existing processes may allow better utilization of the existing infrastructure and should be a focus of future efforts.

LEVEL OF EVIDENCE

Prognostic/Epidemiologic, level III.

Effects of mode and time of EMS transport on the rate and distribution of dead on arrival among trauma population transported to ACSCOT-verified trauma centers in the United States

BACKGROUND

Unintentional injury remains the leading cause of death for adults worldwide. We aimed to investigate the rates and distribution of dead on arrival (DOA) patients according to emergency medical services (EMS) mode of transport (MoT), EMS transport time (TT), injury severity score (ISS), and type of injury.

METHODS

This retrospective study utilized de-identified incident-based data from the American College of Surgeons Trauma Quality Improvement Program Participant Use File (ACS-TQIP PUF) dataset (2013-2018) to study Adult DOA patients. DOA was defined according to the data point, "arrived with no signs of life and did not recover". Patients with unknown vitals and patients with no EMS vitals at the scene (HR = 0, RR = 0, and SBP = 0) were excluded to identify DOAs who died during transport. The DOAs included for analysis were sorted into three groups based on injury severity score [low (ISS < 15), intermediate (ISS = 15-24), and severe (ISS ≥ 25)] and subdivided according to injury type (blunt vs. penetrating), EMS Mode of transport and transport times. Statistical significance was defined as p < 0.05.

RESULTS

The majority of the evaluated 6030 adult DOA patients were male (73.3%) and 18-64 years of age (79.6%). Most patients sustained blunt injuries (58.2%), and the most common mechanism of injury was motor vehicle collisions (MVCs). Patients who traveled by helicopter EMS (HEMS) experienced less deaths than those traveling by ground EMS (GEMS) despite transporting more severely injured patients over longer time intervals. Median HEMS TTs were greater than their GEMS counterparts for blunt and penetrating injuries across all ISS groups but were associated with fewer deaths.

CONCLUSION

Helicopter emergency medical service use with intermediate and severely injured patients with penetrating injuries is associated with a reduced number of DOAs. Future studies should prospectively investigate EMS performance to confirm the findings identified in this retrospective analysis. Additionally, other factors affecting pre-hospital EMS performance (e.g., geographic variations, weather-related characteristics, in-flight interventions/procedures) should be investigated. Finally, the results of this study highlight the need for standardized HEMS utilization triage criteria.

Causes of early mortality in pediatric trauma patients

BACKGROUND

Trauma is the leading cause of death in children, and most deaths occur within 24 hours of injury. A better understanding of the causes of death in the immediate period of hospital care is needed.

METHODS

Trauma admissions younger than 18 years from 2009 to 2019 at a Level I pediatric trauma center were reviewed for deaths (n = 7,145). Patients were stratified into ages 0-6, 7-12, and 13-17 years old. The primary outcome was cause of death, with early death defined as less than 24 hours after trauma center arrival.

RESULTS

There were 134 (2%) deaths with a median age of 7 years. The median time from arrival to death was 14.4 hours (interquartile range, 0.5-87.8 hours). Half (54%) occurred within 24 hours. However, most patients who survived initial resuscitation in the emergency department died longer than 24 hours after arrival (69%). Traumatic brain injury was the most common cause of death (66%), followed by anoxia (9.7%) and hemorrhage (8%). Deaths from hemorrhage were most often in patients sustaining gunshot wounds (73% vs. 11% of all other deaths, p < 0.0001), more likely to occur early (100% vs. 50% of all other deaths, p = 0.0009), and all died within 6 hours of arrival. Death from hemorrhage was more common in adolescents (21.4% of children aged 13-17 vs. 6.3% of children aged 0-6, and 0% of children aged 7-12 p = 0.03). The highest case fatality rates were seen in hangings (38.5%) and gunshot wounds (9.6%).

CONCLUSION

Half of pediatric trauma deaths occurred within 24 hours. Death from hemorrhage was rare, but all occurred within 6 hours of arrival. This is a critical time for interventions for bleeding control to prevent death from hemorrhage in children. Analysis of these deaths can focus efforts on the urgent need for development of new hemorrhage control adjuncts in children.

LEVEL OF EVIDENCE

Epidemiological study, level IV.

Freeze-dried platelets promote clot formation, attenuate endothelial cell permeability, and decrease pulmonary vascular leak in a murine model of hemorrhagic shock

BACKGROUND

Hemorrhagic shock (HS) and trauma induce endothelial barrier compromise, inflammation, and aberrant clotting. We have shown that fresh human platelets (Plts) and Plt extracellular vesicles mitigate vascular leak in murine models of injury. Here, we investigate the potential of freeze-dried platelets (FDPlts) to attenuate pulmonary vascular permeability, decrease inflammation, and promote clotting in a murine model of HS.

METHODS

Human FDPlts were characterized using in vitro assays of Plt marker expression, aggregation, coagulation, and endothelial cell permeability. An intravital model of vascular injury in the mouse cremaster muscle was used to assess the ability of FDPlts to incorporate into clots. Mouse groups subjected to controlled hemorrhage for 90 minutes were (1) lactated Ringer solution (LR), (2) FDPlts, (3) fresh human Plts, (4) murine whole blood (WB), and (5) shams (only instrumented). Hemorrhagic shock mouse endpoints included coagulation, pulmonary vascular permeability, and lung injury.

RESULTS

Freeze-dried Plts expressed Plt-specific markers and retained functionality similar to fresh Plts. In in vitro assays of Plt aggregation, differences were noted. In vivo, FDPlts and Plts were found to incorporate into clots in postcapillary venules in the mouse cremaster muscle. Hemorrhagic shock mice resuscitated with LR displayed increased pulmonary vascular permeability compared with sham (sham, 686.6 ± 359.7; shock-LR, 2,637 ± 954.7; p = 0.001), and treatment with FDPlts or WB attenuated permeability compared with shock: shock-FDPlts, 1,328 ± 462.6 (p = 0.05), and shock-WB, 1,024 ± 370.5 (p = 0.0108). However, human Plts (Days 1-3) did not attenuate vascular leak in HS mice compared with shock-LR (shock-Plts, 3,601 ± 1,581; p = 0.33).

CONCLUSION

FDPlts contribute to clot formation similar to fresh human Plts. FDPlts also attenuated vascular permeability in vitro and in vivo. Mouse WB resuscitation but not fresh human Plts attenuated vascular permeability after HS. These data suggest that the effect of FDPlts may be a suitable alternative to fresh Plts in modulating hemostasis and the endotheliopathy associated with injury.

Injury-related deaths in the Ontario provincial trauma system: a retrospective population-based cohort analysis

BACKGROUND

Although Ontario has an established trauma system, it experiences a substantial burden of morbidity and mortality from injury. Our objective was to describe patterns of fatal injury in Ontario, with a focus on location of death (out of hospital, trauma or non-trauma centre) and receipt of surgical intervention before death.

METHODS

We conducted a retrospective population-based cohort study using linked administrative data on fatal injuries in children and adults (no age restrictions) in Ontario between 2000 and 2016. We identified injury-related deaths in the Ontario Registrar General Death database. We developed descriptive statistics for injury characteristics and causes of death. We calculated the fatal injury incidence rate for each year of the study. The primary outcome was cause of death; the secondary outcome was receipt of surgical intervention.

RESULTS

The analysis included 19 408 people. The mean annual incidence of fatal injury averaged 8.7 (95% confidence interval 7.7-9.6) per 100 000. The most common mechanisms of injury were motor vehicle collisions (12 065, 62.2%), followed by gunshot wounds (3134, 16.1%) and falls (2387, 12.3%). Deaths frequently occurred out of hospital (72.6%), rather than at a trauma centre (14.2%) or non-trauma centre (13.2%). Patients treated at trauma centres were significantly more likely to receive a surgical intervention (standardized difference 0.6) than those treated at non-trauma centres.

INTERPRETATION

Most injury deaths in Ontario occur in the out-of-hospital setting or are managed at non-trauma centres; many patients receive no surgical intervention before death. There are likely opportunities to improve access to specialized injury care in Ontario's trauma system.

Retrieval transfusion protocol in New South Wales, Australia: A retrospective review of the first 5 years

BACKGROUND

Ambulance service blood transfusion is an area of rapid development. In New South Wales, Australia, the blood products carried by ambulance medical teams are often the first available to patients with critical bleeding. In addition to the blood products routinely carried by these teams, the Service created and implemented a method of initiating large-volume, mixed-product transfusions using existing blood banks: the Retrieval Transfusion Procedure (RTP). This article describes the trends and characteristics of New South Wales Ambulance RTP activations.

MATERIALS AND METHODS

This retrospective database review examines the patient records for all RTP activations. Key areas of investigation include logistics, product requests, population demographics, etiologies, physiology, mission timings, and transfusions.

RESULTS

Ambulance medical teams attended 27 531 missions in the reviewed period, 1573 patients received transfusion, and there were 138 RTP activations. Blood products were sourced from 40 banks and transported by police (46.7%), ambulance (27.1%), and helicopter (13.0%) to refueling stops (39.2%), prehospital scenes (24.2%) and hospitals (15.8%). The median time engaged on each mission was 189 minutes for metropolitan and 222 minutes for rural locations. Seventy-eight patients were transfused with RTP blood products; 83.3% were traumas, of which 63.1% were motor vehicle collisions. Up to 18 units of blood products were administered before hospital arrival. There was significant (P < .001) improvement in the mean shock index of transfused patients between the first and final observations recorded.

CONCLUSIONS

Ambulance service extended blood product transfusion is logistically achievable and facilitates emergency transfusions throughout the state with minimal additional infrastructure.