Early Cold Stored Platelet Transfusion Following Severe Injury: A Randomized Clinical Trial.

OBJECTIVE: To determine the feasibility, efficacy, and safety of early cold stored platelet transfusion compared to standard care resuscitation in patients with hemorrhagic shock. SUMMARY BACKGROUND DATA: Data demonstrating the safety and efficacy of early cold stored platelet transfusion are lacking following severe injury. METHODS: A phase 2, multicenter, randomized, open label, clinical trial was performed at five U.S. trauma centers. Injured patients at risk of large volume blood transfusion and the need for hemorrhage control procedures were enrolled and randomized. The intervention was the early transfusion of a single apheresis cold stored platelet unit, stored for up to 14 days vs. standard care resuscitation. The primary outcome was feasibility and the principal clinical outcome for efficacy and safety was 24-hour mortality. RESULTS: Mortality at 24 hours was 5.9% in patients who were randomized to early cold stored platelet transfusion compared to 10.2% in the standard care arm (difference, -4.3%; 95% CI, -12.8% to 3.5%; P=0.26). No significant differences were found for any of the prespecified ancillary outcomes. Rates of arterial and/or venous thromboembolism and adverse events did not differ across treatment groups. CONCLUSIONS AND RELEVANCE: In severely injured patients, early cold stored platelet transfusion is feasible, safe and did not result in a significant lower rate of 24-hour mortality. Early cold stored platelet transfusion did not result in a higher incidence of arterial and/or venous thrombotic complications or adverse events. The storage age of the cold stored platelet product was not associated with significant outcome differences.

Severity-Driven Trends in Mortality in a Large Regionalized Critical Care Transport Service.

OBJECTIVE: The epidemiology accompanying helicopter emergency medical services (HEMS) transport has evolved as agencies have matured and become integrated into regionalized health systems, as evidenced primarily by nationwide systems in Europe. System-level congruence between Europe and the United States, where HEMS is geographically fragmentary, is unclear. In this study, we provide a temporal, epidemiologic characterization of the largest standardized private, nonprofit HEMS system in the United States, STAT MedEvac. METHODS: We obtained comprehensive timing, procedure, and vital signs data from STAT MedEvac prehospital electronic patient care records for all adult patients transported to UPMC Health System hospitals in the period of January 2012 through October 2021. We linked these data with hospital electronic health records available through June 2018 to establish length of stay and vital status at discharge. RESULTS: We studied 90,960 transports and matched 62.8% (n = 57,128) to the electronic health record. The average patient age was 58.6 years ( 19 years), and most were male (57.9%). The majority of cases were interfacility transports (77.6%), and the most common general medical category was nontrauma (72.7%). Sixty-one percent of all patients received a prehospital intervention. Overall, hospital mortality was 15%, and the average hospital length of stay (LOS) was 8.8 days ( 10.0 days). Observed trends over time included increases in nontrauma transports, level of severity, and in-hospital mortality. In multivariable models, case severity and medical category correlated with the outcomes of mortality and LOS. CONCLUSION: In the largest standardized nonprofit HEMS system in the United States, patient mortality and hospital LOS increased over time, whereas the proportion of trauma patients and scene runs decreased.

Prehospital tranexamic acid is associated with a survival benefit without an increase in complications: results of two harmonized randomized clinical trials.

INTRODUCTION: Recent randomized clinical trials have demonstrated that prehospital tranexamic acid (TXA) administration following injury is safe and improves survival. However, the effect of prehospital TXA on adverse events, transfusion requirements and any dose response relationships require further elucidation. METHODS: A secondary analysis was performed using harmonized data from two large, double-blinded, randomized prehospital TXA trials. Outcomes, including 28-day mortality, pertinent adverse events and 24-hour red cell transfusion requirements were compared between TXA and placebo groups. Regression analyses were utilized to determine the independent associations of TXA after adjusting for study enrollment, injury characteristics and shock severity across a broad spectrum of injured patients. Dose response relationships were similarly characterized based upon grams of prehospital TXA administered. RESULTS: A total of 1744 patients had data available for secondary analysis and were included in the current harmonized secondary analysis. The study cohort had an overall mortality of 11.2% and a median injury severity score of 16 (IQR: 5-26). TXA was independently associated with a lower risk of 28-day mortality (HR: 0.72, 95% CI 0.54, 0.96, p = 0.03). Prehospital TXA also demonstrated an independent 22% lower risk of mortality for every gram of prehospital TXA administered (HR: 0.78, 95% CI 0.63, 0.96, p = 0.02). Multivariable linear regression verified that patients who received TXA were independently associated with lower 24-hour red cell transfusion requirements (ß: -0.31, 95% CI -0.61, -0.01, p = 0.04) with a dose-response relationship (ß: -0.24, 95% CI -0.45, -0.02, p = 0.03). There was no independent association of prehospital TXA administration on VTE, seizure, or stroke. CONCLUSIONS: In this secondary analysis of harmonized data from two large randomized interventional trials, prehospital TXA administration across a broad spectrum of injured patients is safe. Prehospital TXA is associated with a significant 28-day survival benefit, lower red cell transfusion requirements at 24 hours and demonstrates a dose-response relationship. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level III.

Identifying Trigger Cues for Hospital Blood Transfusions Based on Ensemble Learning Methods.

Background: Traumatic shock is the leading cause of preventable death with most patients dying within the first 6 hours. This underscores the importance of prehospital interventions, and growing evidence suggests prehospital transfusion improves survival. Optimizing transfusion triggers in the prehospital setting is key to improving outcomes for patients in hemorrhagic shock. Our objective was to identify factors associated with early in-hospital transfusion requirements available to prehospital clinicians in the field to develop a simple algorithm for prehospital transfusion, particularly for patients with occult shock. Methods: We included trauma patients transported by a single critical care transport service to a level I trauma center between 2012 and 2019. We used logistic regression, Fast and Frugal Trees (FFTs), and Bayesian analysis to identify factors associated with early in-hospital blood transfusion as a potential trigger for prehospital transfusion. Results: We included 2,157 patients transported from the scene or emergency department (ED) of whom 207 (9.60%) required blood transfusion within 4 hours of admission. The mean age was 47 (IQR = 28-62) and 1,480 (68.6%) patients were male. From 13 clinically relevant factors for early hospital transfusions, four were incorporated into the FFT in following order: 1) SBP, 2) prehospital lactate concentration, 3) Shock Index, 4) AIS of chest (sensitivity = 0.81, specificity = 0.71). The chosen thresholds were similar to conventional ones. Using conventional thresholds resulted in lower model sensitivity. Consistently, prehospital lactate was among most decisive factors of hospital transfusions identified by Bayesian analysis (OR = 2.31; 95% CI 1.55-3.37). Conclusions: Using an ensemble of frequentist statistics, Bayesian analysis and machine learning, we developed a simple, clinically relevant, prehospital algorithm to help identify patients requiring transfusion within 4 hours of hospital arrival.

Mechanism matters: mortality and endothelial cell damage marker differences between blunt and penetrating traumatic injuries across three prehospital clinical trials.

Injury mechanism is an important consideration when conducting clinical trials in trauma. Mechanisms of injury may be associated with differences in mortality risk and immune response to injury, impacting the potential success of the trial. We sought to characterize clinical and endothelial cell damage marker differences across blunt and penetrating injured patients enrolled in three large, prehospital randomized trials which focused on hemorrhagic shock. In this secondary analysis, patients with systolic blood pressure < 70 or systolic blood pressure < 90 and heart rate > 108 were included. In addition, patients with both blunt and penetrating injuries were excluded. The primary outcome was 30-day mortality. Mortality was characterized using Kaplan-Meier and Cox proportional-hazards models. Generalized linear models were used to compare biomarkers. Chi squared tests and Wilcoxon rank-sum were used to compare secondary outcomes. We characterized data of 696 enrolled patients that met all secondary analysis inclusion criteria. Blunt injured patients had significantly greater 24-h (18.6% vs. 10.7%, log rank p = 0.048) and 30-day mortality rates (29.7% vs. 14.0%, log rank p = 0.001) relative to penetrating injured patients with a different time course. After adjusting for confounders, blunt mechanism of injury was independently predictive of mortality at 30-days (HR 1.84, 95% CI 1.06-3.20, p = 0.029), but not 24-h (HR 1.65, 95% CI 0.86-3.18, p = 0.133). Elevated admission levels of endothelial cell damage markers, VEGF, syndecan-1, TM, S100A10, suPAR and HcDNA were associated with blunt mechanism of injury. Although there was no difference in multiple organ failure (MOF) rates across injury mechanism (48.4% vs. 42.98%, p = 0.275), blunt injured patients had higher Denver MOF score (p < 0.01). The significant increase in 30-day mortality and endothelial cell damage markers in blunt injury relative to penetrating injured patients highlights the importance of considering mechanism of injury within the inclusion and exclusion criteria of future clinical trials.

The Role of Integrated Air Transport System in Managing Abdominal Aortic Aneurysm Rupture Patients.

OBJECTIVE: Ruptured abdominal aortic aneurysms (rAAAs) are highly morbid emergencies. Not all hospitals are equipped to repair them, and an air ambulance network may aid in regionalising speciality care to quaternary referral centres. The association of travel distance by air ambulance on rAAA mortality in patients transferred emergently for repair was examined. METHODS: A retrospective review of institutional data. Adults with rAAA (2002 - 2019) transferred from an outside hospital (OSH) to a single quaternary referral centre for repair via air ambulance were identified. Patients who arrived via ground transport or post-repair at OSH for continued critical care were excluded. Patients were divided into "near" and "far" groups based on the 75th percentile of straight line travel distance (> 72 miles) between hospitals. The primary outcome was 30 day mortality. Multivariate logistic regression was used to assess the association of distance with mortality after adjusting for age, sex, race, cardiovascular comorbidities, and repair type. RESULTS: A total of 290 patients with rAAA were transported a median distance of 40.4 miles (interquartile range 25.5, 72.7) with 215 (74.1%) near and 75 (25.9%) far patients. Both near and far groups had similar ages, sex, and race. There was no difference in pre-operative loss of consciousness, intubation, or cardiac arrest between groups. Endovascular aneurysm repair utilisation and intra-operative aortic occlusion balloon usage were also similar. Both observed (26.8% vs. 23.9%, p = .61) and adjusted odd ratio (0.70, 95% confidence interval 0.36 - 1.39, p = .32) 30 day mortality did not differ significantly between near and far groups. CONCLUSION: Increasing distance travelled during transfer by air ambulance was not associated with worse outcomes in patients with rAAA. The findings support the regionalisation of rAAA repair to large quaternary centres via an integrated and robust air ambulance network.

A multi-center, randomized, double blinded, placebo-controlled trial of amantadine to stimulate awakening in comatose patients resuscitated from cardiac arrest.

Objectives: We hypothesized that the administration of amantadine would increase awakening of comatose patients resuscitated from cardiac arrest. Methods: We performed a prospective, randomized controlled pilot trial, randomizing subjects to amantadine 100mg twice daily or placebo for up to 7 days. The study drug was administered between 72-120 hours after resuscitation and patients with absent N20 cortical responses, early cerebral edema, or ongoing malignant electroencephalography patterns were excluded. Our primary outcome was awakening, defined as following two-step commands, within 28 days of cardiac arrest. Secondary outcomes included length of stay, awakening, time to awakening, and neurologic outcome measured by Cerebral Performance Category (CPC) at hospital discharge. We compared the proportion of subjects awakening and hospital survival using Fisher's exact tests and time to awakening and hospital length of stay using Wilcoxon rank sum tests. Results: After 2 years, we stopped the study due to slow enrollment and lapse of funding. We enrolled 14 subjects (12% of goal enrollment), 7 in the amantadine arm and 7 in the placebo arm. The proportion of patients who awakened within 28 days after cardiac arrest did not differ between amantadine (n=2, 28.57%) and placebo groups (n=3, 42.86%) (p = 1.00). There were no differences in secondary outcomes. Study medication was stopped in three (21%) subjects. Adverse events included a recurrence of seizures (n=2; 14%), both of which occurred in the placebo arm. Conclusion: We could not determine the effect of amantadine on awakening in comatose survivors of cardiac arrest due to small sample size.

Association between First-pass Intubation Success and Enhanced PPE Use during the COVID-19 Pandemic.

OBJECTIVES: We evaluated first-pass endotracheal intubation (ETI) success within the critical care transport (CCT) environment using a natural experiment created by the COVID-19 pandemic. Our primary objective was to evaluate if the use of personal protective equipment (PPE) or the COVID-19 time period was associated with differences in first-pass success rates of ETI within a large CCT system with a high baseline ETI first-pass success rate. We hypothesized that pandemic-related challenges would be associated with decreased first-pass success rates. METHODS: We performed a retrospective before-after cohort study of airway management by CCT personnel relative to the COVID-19 pandemic. We used a mixed effects logistic regression to evaluate the association between enhanced PPE (N95 mask, eye protection) use and the pandemic time period on first-pass intubation success, while controlling for other factors potentially associated with intubation success. Variables in the final model included patient demographics (age, sex, and race), body mass index, medical category (trauma versus non-trauma), interfacility or scene response, blade size (Macintosh 3 versus 4), use of face mask, use of eye protection, and crew member length of service. RESULTS: We identified 1279 cases involving intubation attempts on adult patients during the study period. A total of 1133 cases were included in the final analysis, with an overall first-pass success rate of 95.7% (96.4% pre-COVID-19 and 94.8% during COVID-19). In our final mixed effects logistic regression model, enhanced PPE use and the COVID-19 time period were not associated with first-pass intubation success rate. CONCLUSION: In a large regional CCT system with a high ETI first-pass success rate, neither PPE use nor the COVID-19 time period were associated with differences in ETI first-pass success while controlling for relevant patient and operational factors. Other emergency medical services (EMS) systems may have encountered different effects of pandemic-related PPE use on intubation success rates. Further studies are needed to evaluate the influence of sustained use of enhanced PPE or changes in training or procedural experience on post-pandemic ETI first-pass success rates for non-CCT EMS clinicians.

Prehospital Electroencephalography to Detect Traumatic Brain Injury during Helicopter Transport: A Pilot Observational Cohort Study.

OBJECTIVE: Early recognition of traumatic brain injury (TBI) is important to facilitate time-sensitive care. Electroencephalography (EEG) can identify TBI, but feasibility of EEG has not been evaluated in prehospital settings. We tested the feasibility of obtaining single-channel EEG during air medical transport after trauma. We measured association between quantitative EEG features, early blood biomarkers, and abnormalities on head computerized tomography (CT). METHODS: We performed a pilot prospective, observational study enrolling consecutive patients transported by critical care air ambulance from the scene of trauma to a Level I trauma center. During transport, prehospital clinicians placed a sensor on the patient's forehead to record EEG. We reviewed EEG waveforms and selected 90 seconds of recording for quantitative analysis. EEG data processing included fast Fourier transform to summarize component frequency power in the delta (0-4 Hz), theta (4-8 Hz), and alpha (8-13 Hz) ranges. We collected blood samples on day 1 and day 3 post-injury and measured plasma levels of two brain injury biomarkers (ubiquitin C-terminal hydrolase L1 [UCH-L1] and glial fibrillary acidic protein [GFAP]). We compared predictors between individuals with and without CT-positive TBI findings. RESULTS: Forty subjects were enrolled, with EEG recordings successfully obtained in 34 (85%). Reasons for failure included uncharged battery (n = 5) and user error (n = 1). Data were lost in three cases. Of 31 subjects with data, interpretable EEG signal was recorded in 26 (84%). Mean age was 48 (SD 16) years, 79% were male, and 50% suffered motor vehicle crashes. Eight subjects (24%) had CT-positive TBI. Subjects with and without CT-positive TBI had similar median delta power, alpha power, and theta power. UCH-L1 and GFAP plasma levels did not differ across groups. Delta power inversely correlated with UCH-L1 day 1 plasma concentration (r = -0.60, p = 0.03). CONCLUSIONS: Prehospital EEG acquisition is feasible during air transport after trauma.

Defining the Core Content for Transport Physician Training Programs.

In many parts of the world, emergency medical services (EMS) clinical care is traditionally delivered by different levels or types of EMS clinicians, such as emergency medical technicians and paramedics. In some areas, physicians are also included among the cadre of professionals administering EMS-based care. This is especially true in the interfacility transport (IFT) setting. Though there is significant overlap between the knowledge and skills necessary to safely and effectively provide care in the IFT and prehospital settings, the IFT care environment requires physicians to develop several additional competencies beyond those that are expected of traditional EMS clinicians. NAEMSP first published recommendations regarding what some of these competencies should be in 1983 and subsequently updated those recommendations in 2002. This document is an updated work, given the evolution of the field.

The impact of COVID-19 pandemic on out-of-hospital cardiac arrest: An individual patient data meta-analysis.

AIM: Prior studies have reported increased out-of-hospital cardiac arrests (OHCA) incidence and lower survival during the COVID-19 pandemic. We evaluated how the COVID-19 pandemic affected OHCA incidence, bystander CPR rate and patients' outcomes, accounting for regional COVID-19 incidence and OHCA characteristics. METHODS: Individual patient data meta-analysis of studies which provided a comparison of OHCA incidence during the first pandemic wave (COVID-period) with a reference period of the previous year(s) (pre-COVID period). We computed COVID-19 incidence per 100,000 inhabitants in each of 97 regions per each week and divided it into its quartiles. RESULTS: We considered a total of 49,882 patients in 10 studies. OHCA incidence increased significantly compared to previous years in regions where weekly COVID-19 incidence was in the fourth quartile (>136/100,000/week), and patients in these regions had a lower odds of bystander CPR (OR 0.49, 95%CI 0.29-0.81, p = 0.005). Overall, the COVID-period was associated with an increase in medical etiology (89.2% vs 87.5%, p < 0.001) and OHCAs at home (74.7% vs 67.4%, p < 0.001), and a decrease in shockable initial rhythm (16.5% vs 20.3%, p < 0.001). The COVID-period was independently associated with pre-hospital death (OR 1.73, 95%CI 1.55-1.93, p < 0.001) and negatively associated with survival to hospital admission (OR 0.68, 95%CI 0.64-0.72, p < 0.001) and survival to discharge (OR 0.50, 95%CI 0.46-0.54, p < 0.001). CONCLUSIONS: During the first COVID-19 pandemic wave, there was higher OHCA incidence and lower bystander CPR rate in regions with a high-burden of COVID-19. COVID-19 was also associated with a change in patient characteristics and lower survival independently of COVID-19 incidence in the region where OHCA occurred.

Metabolic Manipulation and Therapeutic Hypothermia.

Hypothermia has multiple physiological effects, including decreasing metabolic rate and oxygen consumption (VO2). There are few human data about the magnitude of change in VO2 with decreases in core temperature. We aimed to quantify to magnitude of reduction in resting VO2 as we reduced core temperature in lightly sedated healthy individuals. After informed consent and physical screening, we cooled participants by rapidly infusing 20 mL/kg of cold (4°C) saline intravenously and placing surface cooling pads on the torso. We attempted to suppress shivering using a 1 mcg/kg intravenous bolus of dexmedetomidine followed by titrated infusion at 1.0 to 1.5 µg/(kg·h). We measured resting metabolic rate VO2 through indirect calorimetry at baseline (37°C) and at 36°C, 35°C, 34°C, and 33°C. Nine participants had mean age 30 (standard deviation 10) years and 7 (78%) were male. Baseline VO2 was 3.36 mL/(kg·min) (interquartile range 2.98-3.76) mL/(kg·min). VO2 was associated with core temperature and declined with each degree decrease in core temperature, unless shivering occurred. Over the entire range from 37°C to 33°C, median VO2 declined 0.7 mL/(kg·min) (20.8%) in the absence of shivering. The largest average decrease in VO2 per degree Celsius was by 0.46 mL/(kg·min) (13.7%) and occurred between 37°C and 36°C in the absence of shivering. After a participant developed shivering, core body temperature did not decrease further, and VO2 increased. In lightly sedated humans, metabolic rate decreases around 5.2% for each 1°C decrease in core temperature from 37°C to 33°C. Because the largest decrease in metabolic rate occurs between 37°C and 36°C, subclinical shivering or other homeostatic reflexes may be present at lower temperatures.

Association Between Emergency Medical Service Agency Volume and Mortality in Trauma Patients.

OBJECTIVE: The aim of this study was to evaluate the association of annual trauma patient volume on outcomes for emergency medical services (EMS) agencies. BACKGROUND: Regionalization of trauma care saves lives. The underlying concept driving this is a volume-outcome relationship. EMS are the entry point to the trauma system, yet it is unknown if a volume-outcome relationship exists for EMS. METHODS: A retrospective analysis of prospective cohort including 8 trauma centers and 20 EMS air medical and metropolitan ground transport agencies. Patients 18 to 90 years old with injury severity scores ≥9 transported from the scene were included. Patient and agency-level risk-adjusted regression determined the association between EMS agency trauma patient volume and early mortality. RESULTS: A total of 33,511 were included with a median EMS agency volume of 374 patients annually (interquartile range: 90-580). Each 50-patient increase in EMS agency volume was associated with 5% decreased odds of 6-hour mortality (adjusted odds ratio=0.95; 95% CI: 0.92-0.99, P =0.03) and 3% decreased odds of 24-hour mortality (adjusted odds ratio=0.97; 95% CI: 0.95-0.99, P =0.04). Prespecified subgroup analysis showed EMS agency volume was associated with reduced odds of mortality for patients with prehospital shock, requiring prehospital airway placement, undergoing air medical transport, and those with traumatic brain injury. Agency-level analysis demonstrated that high-volume (>374 patients/year) EMS agencies had a significantly lower risk-standardized 6-hour mortality rate than low-volume (<374 patients/year) EMS agencies (1.9% vs 4.8%, P <0.01). CONCLUSIONS: A higher volume of trauma patients transported at the EMS agency level is associated with improved early mortality. Further investigation of this volume-outcome relationship is necessary to leverage quality improvement, benchmarking, and educational initiatives.

Hypertension during transfer is associated with poor outcomes in unstable patients with ruptured abdominal aortic aneurysm.

OBJECTIVE: Limited data exist for optimal blood pressure (BP) management during transfer of patients with ruptured abdominal aortic aneurysm (rAAA). This study evaluates the effects of hypertension and severe hypotension during interhospital transfers in a cohort of patients with rAAA in hemorrhagic shock. METHODS: We performed a retrospective, single-institution review of patients with rAAA transferred via air ambulance to a quaternary referral center for repair (2003-2019). Vitals were recorded every 5 minutes in transit. Hypertension was defined as a systolic BP of ≥140 mm Hg. The primary cohort included patients with rAAA with hemorrhagic shock (≥1 episode of a systolic BP of <90 mm Hg) during transfer. The primary analysis compared those who experienced any hypertensive episode to those who did not. A secondary analysis evaluated those with either hypertension or severe hypotension <70 mm Hg. The primary outcome was 30-day mortality. RESULTS: Detailed BP data were available for 271 patients, of which 125 (46.1%) had evidence of hemorrhagic shock. The mean age was 74.2 ± 9.1 years, 93 (74.4%) were male, and the median total transport time from helicopter dispatch to arrival at the treatment facility was 65 minutes (interquartile range, 46-79 minutes). Among the cohort with shock, 26.4% (n = 33) had at least one episode of hypertension. There were no significant differences in age, sex, comorbidities, AAA repair type, AAA anatomic location, fluid resuscitation volume, blood transfusion volume, or vasopressor administration between the hypertensive and nonhypertensive groups. Patients with hypertension more frequently received prehospital antihypertensives (15% vs 2%; P = .01) and pain medication (64% vs 24%; P < .001), and had longer transit times (36.3 minutes vs 26.0 minutes; P = .006). Episodes of hypertension were associated with significantly increased 30-day mortality on multivariable logistic regression (adjusted odds ratio [aOR], 4.71; 95% confidence interval [CI], 1.54-14.39; P = .007; 59.4% [n = 19] vs 40.2% [n = 37]; P = .01). Severe hypotension (46%; n = 57) was also associated with higher 30-day mortality (aOR, 2.82; 95% CI, 1.27-6.28; P = .01; 60% [n = 34] vs 32% [n = 22]; P = .01). Those with either hypertension or severe hypotension (54%; n = 66) also had an increased odds of mortality (aOR, 2.95; 95% CI, 1.08-8.11; P = .04; 58% [n = 38] vs 31% [n = 18]; P < .01). Level of hypertension, BP fluctuation, and timing of hypertension were not significantly associated with mortality. CONCLUSIONS: Hypertensive and severely hypotensive episodes during interhospital transfer were independently associated with increased 30-day mortality in patients with rAAA with shock. Hypertension should be avoided in these patients, but permissive hypotension approaches should also maintain systolic BPs above 70 mm Hg whenever possible.

Prehospital Time Following Traumatic Injury Is Independently Associated With the Need for In-Hospital Blood and Early Mortality for Specific Injury Types.

OBJECTIVE: Treating traumatic hemorrhage is time sensitive. Prehospital care and transport modes (eg, helicopter and ground) may influence in-hospital events. We hypothesized that prehospital time (on-scene time [OST] and total prehospital time [TPT]) and transport mode are associated with same-day transfusion and mortality. Furthermore, we sought to identify regions of anatomic injury that modify the relationship between prehospital time and outcomes in strata corresponding to transport types. METHODS: We obtained prehospital, in-hospital, and trauma registry data from an 8-center cohort of adult nonburn trauma patients from 2017 to 2022 directly transported from the scene to the hospital and having an Injury Severity Score (ISS) > 9 for the Task Order 1 project of the Linking Investigators in Trauma and Emergency Services research network. We excluded patients missing prehospital times, patients < 18 years of age, patients from interfacility transfers, and recipients of prehospital blood. Our same-day outcomes were in-hospital transfusions within 4 hours and 24-hour mortality. Each outcome was adjusted using multivariable logistic regression for covariates of prehospital phases (OST and TPT), mode of transport (helicopter and ground), age, sex, ISS, Glasgow Coma Scale motor subscale score < 6, and field hypotension (systolic blood pressure < 90 mm Hg). We evaluated the association of prehospital time on outcomes for scene missions by transport mode across severe injury patterns defined by Abbreviated Injury Scale > 2 body regions. RESULTS: Of 78,198 subjects, 34,504 were eligible for the study with a mean age of 47.6 ± 20.3 years, ISS of 18 ± 11, OST of 15.9 ± 9.5 minutes, and TPT of 48.7 ± 20.3 minutes. Adjusted for injury severity and demographic factors, transport type significantly modified the relationship between prehospital time and outcomes. The association of OST and TPT with the odds of 4-hour transfusion was absent for the ground emergency medical services (GEMS) cohort and present for the helicopter emergency medical services (HEMS) ambulance cohort, whereas these times were associated with decreased 24-hour mortality for both transport types. When stratifying by injury to most anatomic regions, OST and TPT were associated with a decreased need for 4-hour transfusions in the GEMS cohort. However, OST was associated with increased early transfusion only among patients with severe injuries of the thorax, and this association persisted after adjusting additionally for injury type (odds ratio [OR] = 1.03; 95% confidence interval [CI], 1.00-1.05; P = .02). The presence of polytrauma supported an association between prehospital time and decreased 24-hour mortality for the GEMS cohort (OST: OR = 0.97; 95% CI, 0.95-0.99; P < .01; TPT: OR = 0.99; 95% CI, 0.98-0.99; P = .02), whereas no injuries showed significant association of helicopter prehospital time on mortality after adjustment. CONCLUSION: We determined that transport type affects the relationship between prehospital time and hospital outcomes (4-hour transfusion: positive relationship for HEMS and negative for GEMS, 24-hour mortality: negative for both transport types). Furthermore, we identified regions of anatomic injury that modify the relationship between prehospital time and outcomes in strata corresponding to transport types. Of these regions, most notable were severe isolated injuries to the thorax that supported a positive relationship between HEMS OST and 4-hour transfusions and polytrauma that showed a negative relationship between GEMS OST or TPT and 24-hour mortality after adjustment.

Effect of stomach inflation during cardiopulmonary resuscitation on return of spontaneous circulation in out-of-hospital cardiac arrest patients: A retrospective observational study.

BACKGROUND: Gastric inflation caused by excessive ventilation is a common complication of cardiopulmonary resuscitation. Gastric inflation may further compromise ventilation via increases in intrathoracic pressure, leading to decreased venous return and cardiac output, which may impair out-of-hospital cardiac arrest (OHCA) outcomes. The purpose of this study was to measure the gastric volume of OHCA patients using computed tomography (CT) scan images and evaluate the effect of gastric inflation on return of spontaneous circulation (ROSC). METHODS: In this single-center, retrospective, observational study, CT scan was conducted after ROSC or immediately after death. Total gastric volume was measured. Primary outcome was ROSC. Achievement of ROSC was compared in the gastric distention group and the no gastric distention group; gastric distension was defined as total gastric volume in the ≥75th percentile. Additionally, factors associated with gastric distention were examined. RESULTS: A total of 446 cases were enrolled in the study; 120 cases (27%) achieved ROSC. The median gastric volume was 400 ml for all OHCA subjects; 1068 ml in gastric distention group vs. 287 ml in no gastric distention group. There was no difference in ROSC between the groups (27/112 [24.1%] vs. 93/334 [27.8%], p = 0.440). Gastric distention did not have a significant impact, even after adjustments (adjusted odds ratio 0.73, 95% confidence interval [0.42-1.29]). Increased gastric volume was associated with longer emergency medical service activity time. CONCLUSIONS: We observed a median gastric volume of 400 ml in patients after OHCA resuscitation. In our setting, gastric distention did not prevent ROSC.

Comparing strategies for prehospital transport to specialty care after cardiac arrest.

Outcomes are better when patients resuscitated from out-of-hospital cardiac arrest (OHCA) are treated at specialty centers. The best strategy to transport patients from the scene of resuscitation to specialty care is unknown. METHODS: We performed a retrospective cohort study. We identified patients treated at a single specialty center after OHCA from 2010 to 2021 and used OHCA geolocations to develop a catchment area using a convex hull. Within this area, we identified short term acute care hospitals, OHCA receiving centers, adult population by census block group, and helicopter landing zones. We determined population-level times to specialty care via: (1) direct ground transport; (2) transport to the nearest hospital followed by air interfacility transfer; and (3) ground transport to air ambulance. We used an instrumental variable (IV) adjusted probit regression to estimate the causal effect of transport strategy on functionally favorable survival to hospital discharge. RESULTS: Direct transport to specialty care by ground to air ambulance had the shortest population-level times from OHCA to specialty care (median 56 [IQR 47-66] minutes). There were 1,861 patients included in IV regression of whom 395 (21%) had functionally favorable survival. Most (n = 1,221, 66%) were transported to the nearest hospital by ground EMS then to specialty care by air. Patient outcomes did not differ across transport strategies in our IV analysis. DISCUSSION: We did not find strong evidence in favor of a particular strategy for transport to specialty care after OHCA. Population level time to specialty care was shortest with ground ambulance transport to the nearest helicopter landing zone.

Duration of cardiopulmonary resuscitation and phenotype of post-cardiac arrest brain injury.

BACKGROUND: Patients resuscitated from cardiac arrest have variable severity of primary hypoxic ischemic brain injury (HIBI). Signatures of primary HIBI on brain imaging and electroencephalography (EEG) include diffuse cerebral edema and burst suppression with identical bursts (BSIB). We hypothesize distinct phenotypes of primary HIBI are associated with increasing cardiopulmonary resuscitation (CPR) duration. METHODS: We identified from our prospective registry of both in-and out-of-hospital CA patients treated between January 2010 to January 2020 for this cohort study. We abstracted CPR duration, neurological examination, initial brain computed tomography gray to white ratio (GWR), and initial EEG pattern. We considered four phenotypes on presentation: awake; comatose with neither BSIB nor cerebral edema (non-malignant coma); BSIB; and cerebral edema (GWR ≤ 1.20). BSIB and cerebral edema were considered as non-mutually exclusive outcomes. We generated predicted probabilities of brain injury phenotype using localized regression. RESULTS: We included 2,440 patients, of whom 545 (23%) were awake, 1,065 (44%) had non-malignant coma, 548 (23%) had BSIB and 438 (18%) had cerebral edema. Only 92 (4%) had both BSIB and edema. Median CPR duration was 16 [IQR 8-28] minutes. Median CPR duration increased in a stepwise manner across groups: awake 6 [3-13] minutes; non-malignant coma 15 [8-25] minutes; BSIB 21 [13-31] minutes; cerebral edema 32 [22-46] minutes. Predicted probability of phenotype changes over time. CONCLUSIONS: Brain injury phenotype is related to CPR duration, which is a surrogate for severity of HIBI. The sequence of most likely primary HIBI phenotype with progressively longer CPR duration is awake, coma without BSIB or edema, BSIB, and finally cerebral edema.

The Geography of Injuries in Trauma Systems: Using Home as a Proxy for Incident Location.

INTRODUCTION: Effective trauma system organization is crucial to timely access to care and requires accurate understanding of injury and resource locations. Many systems rely on home zip codes to evaluate geographic distribution of injury; however, few studies have evaluated the reliability of home as a proxy for incident location after injury. METHODS: We analyzed data from a multicenter prospective cohort collected from 2017 to 2021. Injured patients with both home and incident zip codes were included. Outcomes included discordance and differential distance between home and incident zip code. Associations of discordance with patient characteristics were determined by logistic regression. We also assessed trauma center catchment areas based on home versus incident zip codes and variation regionally at each center. RESULTS: Fifty thousand one hundred seventy-five patients were included in the analysis. Home and incident zip codes were discordant in 21,635 patients (43.1%). Injuries related to motor vehicles (aOR: 4.76 [95% CI 4.50-5.04]) and younger adults 16-64 (aOR: 2.46 [95% CI 2.28-2.65]) were most likely to be discordant. Additionally, as injury severity score increased, discordance increased. Trauma center catchment area differed up to two-thirds of zip codes when using home versus incident location. Discordance rate, discordant distance, and catchment area overlap between home and incident zip codes all varied significantly by geographic region. CONCLUSIONS: Home location as proxy for injury location should be used with caution and may impact trauma system planning and policy, especially in certain populations. More accurate geolocation data are warranted to further optimize trauma system design.

Prehospital tranexamic acid is associated with a dose-dependent decrease in syndecan-1 after trauma: A secondary analysis of a prospective randomized trial.

BACKGROUND: In the Study of Tranexamic Acid During Air and Ground Prehospital Transport (STAAMP) Trial, prehospital tranexamic acid (TXA) was associated with lower mortality in specific patient subgroups. The underlying mechanisms responsible for a TXA benefit remain incompletely characterized. We hypothesized that TXA may mitigate endothelial injury and sought to assess whether TXA was associated with decreased endothelial or tissue damage markers among all patients enrolled in the STAAMP Trial. METHODS: We collected blood samples from STAAMP Trial patients and measured markers of endothelial function and tissue damage including syndecan-1, soluble thrombomodulin (sTM), and platelet endothelial cell adhesion molecule-1 at hospital admission (0 hours) and 12 hours, 24 hours, and 72 hours after admission. We compared these marker values for patients in each treatment group during the first 72 hours, and modeled the relationship between TXA and marker concentration using regression analysis to control for potential confounding factors. RESULTS: We analyzed samples from 766 patients: 383 placebo, 130 abbreviated dosing, 119 standard dosing, and 130 repeat dosing. Lower levels of syndecan-1, TM, and platelet endothelial cell adhesion molecule measured within the first 72 hours of hospital admission were associated with survival at 30 days ( p < 0.001). At hospital admission, syndecan-1 was lower in the TXA group (28.30 [20.05, 42.75] vs. 33.50 [23.00, 54.00] p = 0.001) even after controlling for patient, injury, and prehospital factors ( p = 0.001). For every 1 g increase in TXA administered over the first 8 hours of prehospital transport and hospital admission, there was a 4-ng/mL decrease in syndecan-1 at 12 hours controlling for patient, injury, and treatment factors ( p = 0.03). CONCLUSION: Prehospital TXA was associated with decreased syndecan-1 at hospital admission. Syndecan-1 measured 12 hours after admission was inversely related to the dose of TXA received. Early prehospital and in-hospital TXA may decrease endothelial glycocalyx damage or upregulate vascular repair mechanisms in a dose-dependent fashion. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level III.