Health service use in major trauma survivors: a population-based cohort study from Ontario, Canada.

BACKGROUND: Little is known about how major trauma survivors access health services in the years following their injury. Our study sought to characterize patterns of health services use in trauma survivors following discharge from a provincial trauma centre and to identify sociodemographic factors associated with service utilization. METHODS: We conducted a population-based retrospective case-control study using linked administrative data on trauma survivors' population-based controls between April 1, 2011, to March 31, 2021. For each major trauma survivor, we matched four cases based on age and sex. The primary outcome was the composite rate (sum) of health service use episodes including outpatient visits to family physicians and specialists, emergency department (ED) visits, and acute care hospital admissions during the five-year period following discharge from the trauma centre. We used multivariate regression to compute rate ratios comparing the rates of health service use in trauma survivors versus controls and to assess for associations between sociodemographic variables and health services use. RESULTS: The study cohort consisted of a total of 273,406 individuals: 55,060 trauma survivors and 218,346 controls. Trauma survivors were predominately males (71%) with a median age of 46 years (IQR: 26-65 years). Health service use in trauma survivors peaked within a year of hospital discharge but remained increased throughout the follow up period. Trauma survivorship was associated with a 56% increase in overall health services use (Adjusted Rate Ratio 1.56, 95% CI: 1.55-1.57), including an 88% increase in hospital admissions (Adjusted Rate Ratio 1.88, 95% CI: 1.85-1.92). Male sex and rural residence were associated with a reduced overall use of health services but greater use of ED services. CONCLUSION: Major trauma survivors have long-term health services needs that persist for years after discharge from the trauma centre. Future research should focus on the understanding why trauma survivors have prolonged health services requirements and ensure care needs are aligned with service delivery. LEVEL OF EVIDENCE: Retrospective cohort study, Level IV.

Effects of doxycycline dose rate and pre-adulticide wait period on heartworm-associated pathology and adult worm mass.

BACKGROUND: The American Heartworm Society canine guidelines recommend treatment with doxycycline prior to adulticide administration to reduce levels of Wolbachia and its associated metabolites, which are known to be a leading cause of pulmonary pathology. Studies have determined that doxycycline administered at 10 mg/kg BID for 28 days is an effective dose for eliminating Wolbachia, but what has not been determined is the clinical relevance of this elimination. The current guidelines also recommend a 30-day wait period following administration of doxycycline to allow for clearance of metabolites, such as Wolbachia surface protein, and for further reduction in heartworm biomass before administration of adulticide. Reducing the doxycycline dose and eliminating the wait period may carry practical benefits for the animal, client, and practitioner. METHODS: To investigate these treatment practices, Dirofilaria immitis adults were surgically transplanted into each of 45 dogs, which were divided into nine study groups of five dogs each. Seventy-five days after transplantation, two groups each were administered 5, 7.5, or 10 mg/kg BID doxycycline orally for 28 days and 6 µg/kg ivermectin monthly, with three untreated groups serving as controls. Study animals were necropsied and examined prior to treatment as well as 30 and 60 days post-treatment. RESULTS: Mean worm weight was unaffected by dosage but exhibited a significant increase at 30 days and significant decrease at 60 days post-treatment, including in control groups. Histopathology lesion scores did not significantly differ among groups, with the exception of the lung composite score for one untreated group. Liver enzymes, the levels of which are a concern in doxycycline treatment, were also examined, with no abnormalities in alanine aminotransferase or alkaline phosphatase observed. CONCLUSIONS: No consistent worsening of tissue lesions was observed with or without the AHS-recommended 30-day wait period, nor did reduced dosages of doxycycline lead to worsening of pathology or any change in efficacy in depleting worm weight. Mean worm weight did significantly increase prior to, and decrease following, the wait period. Future work that also includes adulticide treatment (i.e. melarsomine) will study treatment recommendations that may improve both animal health and owner compliance.

The Domestic Dog as a Laboratory Host for Brugia malayi.

Of the three nematodes responsible for lymphatic filariasis in humans, only Brugia malayi is actively maintained in research settings owing to its viability in small animal hosts, principal among which is the domestic cat. While the microfilaremic feline host is necessary for propagation of parasites on any significant scale, this system is plagued by a number of challenges not as pronounced in canine filarial models. For this reason, we investigated the capacity in which dogs may serve as competent laboratory hosts for B. malayi. We infected a total of 20 dogs by subcutaneous injection of 500 B. malayi third-stage larvae (L3) in either a single (n = 10) or repeated infection events (125 L3 per week for four weeks; n = 10). Within each group, half of the individuals were injected in the inguinal region and half in the dorsum of the hind paw. To track the course of microfilaremia in this host, blood samples were examined by microscopy biweekly for two years following infection. Additionally, to identify cellular responses with potential value as predictors of patency, we measured peripheral blood leukocyte counts for the first year of infection. A total of 10 of 20 dogs developed detectable microfilaremia. Peak microfilaria density varied but attained levels useful for parasite propagation (median = 1933 mL-1; range: 33-9950 mL-1). Nine of these dogs remained patent at 104 weeks. A two-way ANOVA revealed no significant differences between infection groups in lifetime microfilaria production (p = 0.42), nor did regression analysis reveal any likely predictive relationships to leukocyte values. The results of this study demonstrate the competence of the dog as a host for B. malayi and its potential to serve in the laboratory role currently provided by the cat, while also clarifying the potential for zoonosis in filariasis-endemic regions.

Longer-term rates of survival and reintervention after thoracic endovascular aortic repair (TEVAR) for blunt aortic injury: a retrospective population-based cohort study from Ontario, Canada.

Objectives: Blunt aortic injury (BAI) is associated with a high rate of mortality. Thoracic endovascular aortic repair (TEVAR) has emerged as the preferred treatment option for patients with BAI. In this study, we compare the longer-term outcomes of patients receiving TEVAR with other treatment options for BAI. Methods: We conducted a retrospective cohort study using administrative health data on patients with BAI in Ontario, Canada between 2009 and 2020. Patients with BAI and who survived at least 24 hours after hospital admission were identified using diagnostic codes. We classified patients as having received TEVAR, open surgical, hybrid repair, or medical management as their initial treatment approach based on procedure codes. The primary outcome was survival to maximum follow-up. Secondary outcomes included aorta-related mortality or aortic reintervention. Cox's proportional hazards models were used to estimate the effect of TEVAR on survival. Results: 427 patients with BAI were followed for a median of 3 years (IQR: 1-6 years), with 348 patients (81.5%) surviving. Survival to maximum follow-up did not differ between treatment groups: TEVAR: 79%, surgical repair: 63.6%, hybrid repair: 85.7%, medical management: 83.3% (p=0.10). In adjusted analyses, TEVAR was not associated with improved survival compared with surgical repair (HR: 0.6, 95% CI: 0.3 to 1.6), hybrid repair (HR: 1.4, 95% CI: 0.5 to 3.6), or medical management (HR: 1.5, 95% CI: 0.8 to 2.6). Aortic reinterventions were required in only 2.6% of surviving patients but were significantly more common in the TEVAR group (p<0.01). Conclusions: The longer-term survival from BAI appears highly favorable with low rates of reintervention and death in the years after injury, regardless of the initial treatment approach. Level of evidence: IV, Therapeutic study.

Emergency department return visits and hospital admissions in trauma team assessed patients initially discharged from the emergency department: A population-based cohort study.

BACKGROUND: Many injured patients are transported directly to trauma centers, found to be minimally injured, and discharged directly home from the emergency department (ED). Our objectives were to characterize the short-term outcomes in this discharged patient population and to identify patient factors predictive of ED return visits. METHODS: We conducted a retrospective population-based cohort study using linked administrative data sets involving patients assessed at trauma centers in Ontario, Canada between April 1, 2009, and March 31, 2020. Patients who were assessed by a trauma team and discharged directly home from ED were included. The primary outcome was the percentage of patients with an ED return visit within 14 days. We used multivariate logistic regression analyses to identify patient characteristics predictive of at least one ED return visit. RESULTS: There were 5,550 patients included in the study. A total of 1,004 (18.1%) of patients had at least one ED return visit, but only 100 patients (1.8%) were admitted to hospital following initial discharge. Common reasons for ED return visits included wound care concerns (17.2%), head injury complaints (15.6%), and substance misuse (6.8%). Rural residence (odds ratio [OR], 1.83; 95% CI, 1.45-2.29), history of anxiety disorder (OR, 2.05; 95% CI, 1.54-2.73), high baseline ED usage (OR, 2.58; 95% CI, 2.03-3.28), penetrating injury (OR, 1.42; 95% CI, 1.20-1.68), and extremity fracture (OR, 1.52; 95% CI, 1.24-1.88) predicted return visits. CONCLUSION: Patients discharged directly have high rates of ED return visits but low rates of hospital admission or delayed surgical intervention. Trauma services should expand quality assurance initiatives to capture return visits, understand any gaps in clinical service provision, and aim to minimize unnecessary ED return visits. LEVEL OF EVIDENCE: Prognostic/Epidemiological; Level IV.

The Course of Brugia malayi Microfilaremia in Experimentally Infected Cats.

As one of the causative agents of lymphatic filariasis in humans, Brugia malayi has been established as the laboratory model of choice for studying this infection owing to its viability in small animal hosts, with the domestic cat being significant among these. The usefulness of individual feline infections is highly dependent on the levels of circulating microfilariae in the blood; thus, characterizing the course of microfilaremia benefits our understanding of this model. In B. malayi-endemic regions, cats are also known reservoirs of infection, and describing microfilaremia in a controlled setting may improve transmission modeling. We followed the course of B. malayi infection in 10 experimentally infected cats from inoculation to ultimate resolution. Seven cats developed patency, with a peak microfilaria concentration of 6525/mL. In addition, to identify cellular responses with potential value as predictors of patency, we measured the peripheral blood leukocyte counts during the first 8 months of infection and tested for correlations with lifelong microfilaria production. No strong relationships were observed, though cell values did appear to shift with the maturation phases of the parasite. The data we present reflect the course of microfilaremia in an important laboratory model under controlled conditions.

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.

A rapid, parasite-dependent cellular response to Dirofilaria immitis in the Mongolian jird (Meriones unguiculatus).

BACKGROUND: The Mongolian jird (Meriones unguiculatus) has long been recognized as a permissive host for the filarial parasite Brugia malayi; however, it is nonpermissive to another filarial parasite, canine heartworm (Dirofilaria immitis). By elucidating differences in the early response to infection, we sought to identify mechanisms involved in the species-specific clearance of these parasites. We hypothesized that the early clearance of D. immitis in intraperitoneal infection of the jird is immune mediated and parasite species dependent. METHODS: Jird peritoneal exudate cells (PECs) were isolated and their attachment to parasite larvae assessed in vitro under various conditions: D. immitis and B. malayi cultured separately, co-culture of both parasites, incubation before addition of cells, culture of heat-killed parasites, and culture with PECs isolated from jirds with mature B. malayi infection. The cells attaching to larvae were identified by immunohistochemistry. RESULTS: In vitro cell attachment to live D. immitis was high (mean = 99.6%) while much lower for B. malayi (mean = 5.56%). This species-specific attachment was also observed when both filarial species were co-cultured, with no significant change from controls (U(9, 14) = 58.5, p = 0.999). When we replicated these experiments with PECs derived from jirds subcutaneously infected with B. malayi, the results were similar (99.4% and 4.72% of D. immitis and B. malayi, respectively, exhibited cell attachment). Heat-killing the parasites significantly reduced cell attachment to D. immitis (mean = 71.9%; U(11, 14) = 7.5, p < 0.001) while increasing attachment to B. malayi (mean = 16.7%; U(9, 15) = 20, p = 0.002). Cell attachment to both species was reduced when larvae were allowed a 24-h pre-incubation period prior to the addition of cells. The attaching cells were identified as macrophages by immunohistochemistry. CONCLUSIONS: These results suggest a strongly species-dependent response from which B. malayi could not confer protection by proxy in co-culture. The changes in cell attachment following heat-killing and pre-incubation suggest a role for excretory/secretory products in host immune evasion and/or antigenicity. The nature of this attachment is the subject of ongoing study and may provide insight into filarial host specificity.

Drug Resistance in Filarial Parasites Does Not Affect Mosquito Vectorial Capacity.

Parasite drug resistance presents a major obstacle to controlling and eliminating vector-borne diseases affecting humans and animals. While vector-borne disease dynamics are affected by factors related to parasite, vertebrate host and vector, research on drug resistance in filarial parasites has primarily focused on the parasite and vertebrate host, rather than the mosquito. However, we expect that the physiological costs associated with drug resistance would reduce the fitness of drug-resistant vs. drug-susceptible parasites in the mosquito wherein parasites are not exposed to drugs. Here we test this hypothesis using four isolates of the dog heartworm (Dirofilaria immitis)-two drug susceptible and two drug resistant-and two vectors-the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Ae. albopictus)-as our model system. Our data indicated that while vector species had a significant effect on vectorial capacity, there was no significant difference in the vectorial capacity of mosquitoes infected with drug-resistant vs. drug-susceptible parasites. Consequently, contrary to expectations, our data indicate that drug resistance in D. immitis does not appear to reduce the transmission efficiency of these parasites, and thus the spread of drug-resistant parasites in the vertebrate population is unlikely to be mitigated by reduced fitness in the mosquito vector.

Canine gastrointestinal nematode transmission potential in municipal dog parks in the southeast United States.

Monthly canine parasite prophylactic products prevent not only adult heartworm infection, but also patent infections with specific gastrointestinal parasites. While most monthly products control and treat certain hookworm and roundworm infections, fewer are labeled for whipworm (Trichuris vulpis). Therefore, we hypothesized that fecal samples collected from municipal dog parks will have a greater prevalence of whipworm eggs compared to hookworm and roundworm eggs. In this study, canine fecal samples were collected from municipal dog parks in three southeastern states, with up to 20 fecal samples were collected from each park. A total of 200 fecal samples were obtained from dog parks in Georgia, North Carolina, and South Carolina. All fecal samples were examined for the presence of gastrointestinal helminths by a simple centrifugal flotation using sheather's sugar flotation solution. Of the 200 samples collected, 27% were positive for gastrointestinal helminths by fecal flotation. Of these infected fecal samples, 8.5%, 17%, and 1.5% contained whipworm, hookworm, and roundworm, respectively. However, the majority of hookworm-positive samples were collected from one park, whereas whipworm and roundworm samples were collected from multiple parks. These results could indicate that dogs are at risk of infection by all three parasites at dog parks, and that preventive strategies may need to be tailored not only to the specific region, but to specific infected dog parks.

Acetic acid as an alternative reagent in the modified Knott test.

The suitability of acetic acid as a safer alternative to formalin in the modified Knott test was evaluated for the diagnosis of canine heartworm (Dirofilaria immitis). Microfilaria concentration was measured by both methods and found to agree within reasonable limits (-5.84 % bias; -88.1-76.4 % limits of agreement). The level of agreement was lower when samples were prepared with a 24 h delay, but this was due to the formalin method tending to yield lower counts (-20.1 % bias; -90.5-50.2 % limits of agreement). Clearing the sample of hemoglobin improves readability and is a key feature of the modified Knott test. Hemolysis was significantly lower in the acetic acid method than the formalin method as measured by red blood cell count (6.83 × 106 and 8.79 × 106 cells/ml, respectively; p = 0.015) and absorbance at 415 nm (33.20 and 34.75, respectively; p < 0.001). Visual assessment, however, revealed little practical difference in readability. Finally, lengths of microfilariae were measured to ensure the validity of species identification by the acetic acid method; mean length was significantly shorter after acetic acid treatment (273 µm) than formalin treatment (316 µm; p < 0.001). Length reduction was also observed in acetic acid-treated Acanthocheilonema reconditum (254 µm versus 262 µm; p = 0.035), though these samples were stored prior to testing and are not directly comparable. We conclude that, while the readability of samples is similar for both methods, species differentiation must still be accomplished by other means. For most clinical purposes in determining the presence or absence of blood circulating microfilariae, however, acetic acid appears to be a suitable alternative to formalin in the modified Knott test.

Mental health outcomes after major trauma in Ontario: a population-based analysis.

BACKGROUND: Major injury continues to be a common source of morbidity and mortality; improving the functional recovery of survivors of major trauma requires a better understanding of the mental health outcomes that may occur in this population. We assessed the association between major trauma and the development of a new mental health diagnosis or death by suicide. METHODS: We completed a population-based, self-controlled, longitudinal cohort analysis using linked administrative data on patients treated for major trauma in Ontario between 2005 and 2010. All survivors were included and composite rates of mental health diagnoses during inpatient admissions were compared between the 5 years after injury and the 5 years before injury, using Poisson regression with generalized estimating equations. The incidence of suicide was calculated for the 5 years after injury. Risk factors for suicide were calculated using Cox proportional hazard regression analyses. RESULTS: The analysis included 19 338 patients, predominantly men (70.7%) from urban areas (82.6%), with unintentional (89%), blunt injuries (93.4%). Overall, trauma was associated with a 40% increase in the postinjury rate of mental health diagnoses (incidence rate ratio [IRR] 1.4, 95% [confidence interval] CI 1.1 to 1.8). The suicide rate was 70 per 100 000 patients per year, substantially higher than the population average. Risk factors for completing suicide were prior inpatient diagnosis of mood disorder (hazard ratio [HR] 4.3, 95% CI 2.1 to 8.8) and self-inflicted injury (HR 7.8, 95% CI 3.9 to 15.4). INTERPRETATION: Survivors of major trauma are at a heightened risk of developing mental health conditions or death by suicide in the years after their injury. Patients with pre-existing mental health disorders or who are recovering from a self-inflicted injury are at particularly high risk.

Differential phase-shift-keying demodulation by coherent perfect absorption in silicon photonics.

We demonstrate a novel differential phase-shift-keying (DPSK) demodulator based on coherent perfect absorption (CPA). Our DPSK demodulator chip device, which incorporates a silicon ring resonator, two bus waveguide inputs, and monolithically integrated detectors, operates passively at a bit rate of 10 Gbps at telecommunication wavelengths, and fits within a mm-scale footprint. Critical coupling is used to achieve efficient CPA by tuning the gap between the ring and bus waveguides. The device has a vertical eye opening of 12.47 mV and a quality factor exceeding 3×104. The fundamental principle behind this photonic circuit can be extended to other formats of integrated demodulators.

A diagnostic algorithm for evaluating cases of potential macrocyclic lactone-resistant heartworm.

BACKGROUND: The emergence of macrocyclic lactone resistance in canine heartworm poses a substantial threat to what is currently the only effective, FDA-approved available method of prevention. Further study of the biotypes is necessary to understand the mechanism of resistance and evaluate novel prevention options. Identifying cases of drug-resistant infection remains problematic, however, especially when poor compliance and insufficient testing are concerns. Furthermore, a definitive demonstration of resistance requires experimental infection and treatment, which is prohibitively costly. METHODS: With the aim of identifying likely cases of macrocyclic lactone-resistant heartworm and preventing their continued spread, we describe an algorithm for determining the likelihood of drug resistance and appropriate treatment strategies for each case. RESULTS: This algorithm relies on the microfilarial suppression test (MFST), which has been used previously as an efficient and discrete measure of suspected resistance. By standardizing this method in a format that is readily available to practitioners, it could become possible to preliminarily survey the emergence and spread of resistance. CONCLUSION: Heartworm isolates identified through this method can be used in research to better understand macrocyclic lactone resistance so prevention strategies can be adapted.

Evaluation of the larval migration inhibition assay for detecting macrocyclic lactone resistance in Dirofilaria immitis.

Anthelmintics of the macrocyclic lactone (ML) drug class are widely used as preventives against the canine heartworm (Dirofilaria immitis). Over the past several years, however, reports of ML lack of efficacy (LOE) have emerged, in which dogs develop mature heartworm infection despite the administration of monthly prophylactics. More recently, isolates from LOE cases have been used to infect laboratory dogs and the resistant phenotype has been confirmed by the establishment of adult worms in the face of ML treatment at normally preventive dosages. Testing for and monitoring resistance in D. immitis requires a validated biological or molecular diagnostic assay. In this study, we assessed a larval migration inhibition assay (LMIA) that we previously optimized for use with D. immitis third-stage larvae (L3). We used this assay to measure the in vitro ML susceptibilities of a known-susceptible laboratory strain of D. immitis and three highly suspected ML-resistant isolates originating from three separate LOE cases; progeny from two of these isolates have been confirmed ML-resistant by treatment of an infected dog in a controlled setting. A nonlinear regression model was fit to the dose-response data, from which IC50 values were calculated. The D. immitis LMIA yielded consistent and reproducible dose-response data; however, no statistically significant differences in drug susceptibility were observed between control and LOE parasites. Additionally, the drug concentrations needed to paralyze the L3 were much higher than those third- and fourth-stage larvae would experience in vivo. IC50 values ranged from 1.57 to 5.56µM (p≥0.19). These data could suggest that ML resistance in this parasite is not mediated through a reduced susceptibility of L3 to the paralytic effects of ML drugs, and therefore motility-based assays are likely not appropriate for measuring the effects of MLs against D. immitis in this target stage.

Efficient photon triplet generation in integrated nanophotonic waveguides.

Generation of entangled photons in nonlinear media constitutes a basic building block of modern photonic quantum technology. Current optical materials are severely limited in their ability to produce three or more entangled photons in a single event due to weak nonlinearities and challenges achieving phase-matching. We use integrated nanophotonics to enhance nonlinear interactions and develop protocols to design multimode waveguides that enable sustained phase-matching for third-order spontaneous parametric down-conversion (TOSPDC). We predict a generation efficiency of 0.13 triplets/s/mW of pump power in TiO2-based integrated waveguides, an order of magnitude higher than previous theoretical and experimental demonstrations. We experimentally verify our device design methods in TiO2 waveguides using third-harmonic generation (THG), the reverse process of TOSPDC that is subject to the same phase-matching constraints. We finally discuss the effect of finite detector bandwidth and photon losses on the energy-time coherence properties of the expected TOSPDC source.

Prehospital traumatic cardiac arrest: Management and outcomes from the resuscitation outcomes consortium epistry-trauma and PROPHET registries.

BACKGROUND: Traumatic arrests have historically had poor survival rates. Identifying salvageable patients and ideal management is challenging. We aimed to (1) describe the management and outcomes of prehospital traumatic arrests; (2) determine regional variation in survival; and (3) identify Advanced Life Support (ALS) procedures associated with survival. METHODS: This was a secondary analysis of cases from the Resuscitation Outcomes Consortium Epistry-Trauma and Prospective Observational Prehospital and Hospital Registry for Trauma (PROPHET) registries. Patients were included if they had a blunt or penetrating injury and received cardiopulmonary resuscitation. Logistic regression analyses were used to determine the association between ALS procedures and survival. RESULTS: We included 2,300 patients who were predominately young (Epistry mean [SD], 39 [20] years; PROPHET mean [SD], 40 [19] years), males (79%), injured by blunt trauma (Epistry, 68%; PROPHET, 67%), and treated by ALS paramedics (Epistry, 93%; PROPHET, 98%). A total of 145 patients (6.3%) survived to hospital discharge. More patients with blunt (Epistry, 8.3%; PROPHET, 6.5%) vs. penetrating injuries (Epistry, 4.6%; PROPHET, 2.7%) survived. Most survivors (81%) had vitals on emergency medical services arrival. Rates of survival varied significantly between the 12 study sites (p = 0.048) in the Epistry but not PROPHET (p = 0.14) registries.Patients in the PROPHET registry who received a supraglottic airway insertion or intubation experienced decreased odds of survival (adjusted OR, 0.27; 95% confidence interval, 0.08-0.93; and 0.37; 95% confidence interval, 0.17-0.78, respectively) compared to those receiving bag-mask ventilation. No other procedures were associated with survival. CONCLUSIONS: Survival from traumatic arrest may be higher than expected, particularly in blunt trauma and patients with vitals on emergency medical services arrival. Although limited by confounding and statistical power, no ALS procedures were associated with increased odds of survival. LEVEL OF EVIDENCE: Prognostic study, level IV.