Using Virtual Reality to teach ultrasound-guided needling skills for regional anaesthesia: A randomised controlled trial.

STUDY OBJECTIVE: We previously designed and validated a virtual reality-based simulator to help train novices in ultrasound-guided needling skills necessary for safe and competent ultrasound-guided regional anaesthesia. This study was designed to compare the performance and error rates of novices trained by a human faculty aided with the assistance of this virtual reality simulator (virtual reality-assisted training), versus novices trained wholly by humans (conventional training). DESIGN, SETTING, AND PARTICIPANTS: In this single centre, randomised controlled study, we used a standardised teaching protocol, rigorous blinding, iterative training of assessors, and validated global rating scale and composite error score checklists to assess skills learning of novice participants. MAIN RESULTS: We recruited 45 novices and scored 270 assessments of performance and error rates. Inter-rater correlation coefficient of reliability of scoring between assessors for the global rating scale was 0.84 (95%CI 0.68-0.92) and for the composite error score checklist was 0.87 (95%CI 0.73-0.93). After adjustment for age, sex, Depression, Anxiety and Stress-21, and baseline score, there was no statistical difference for virtual reality-assisted training compared to conventional training in final global rating score (average treatment effect -3.30 (95%CI-13.07-6.48), p = 0.51) or in the final composite error score (average treatment effect 1.14 (95%CI -0.60-2.88), p = 0.20). Realism in the virtual reality simulator was similar to real-life when measured by the Presence Questionnaire, all components p > 0.79; and task workload assessed by the NASA-Task Load Index was not statistically different between groups, average treatment effect 5.02 (95%CI -3.51-13.54), p = 0.25. Results were achieved in the virtual reality-assisted group with half the human faculty involvement. CONCLUSION: Novices trained using a hybrid, virtual reality-assisted teaching program showed no superiority to novices trained using a conventional teaching program, but with less burden on teaching resources.

Eastern Association for the Surgery of Trauma (EAST) vs Western Trauma Association (WTA): How a Level 1 Trauma Center Splits the Difference in Resuscitative Thoracotomy.

Background Resuscitative thoracotomy (RT) is performed in severe trauma cases as a final lifesaving effort. Prominent, yet differing, practice management guidelines exist from Eastern Association for the Surgery of Trauma (EAST) and Western Trauma Association (WTA). This study evaluates all RTs performed from 2012 to 2019 at an urban Level 1 trauma center for management guideline indication and subsequent outcomes. Methods Our trauma registry was queried to identify RT cases from 2012 to 2019. Data was collected on patient demographics, prehospital presentation, cardiopulmonary resuscitation (CPR) requirements, and resuscitation provided. Survival to the operating room, intensive care unit, and overall were recorded. Information was compared with regard to EAST and WTA criteria. Results Eighty-seven patients who underwent RTs were included. WTA guidelines were met in 78/87 (89.7%) of cases, comparatively EAST guidelines were met in every case. Within the EAST criteria, conditional and strong recommendations were met in 70/87 (80.4%) and 17/87 (19.5%) of cases, respectively. In nine cases (10.3%) indications were discordant, each meeting conditional indication by EAST and no indication by WTA. All patients that survived to the operating room (OR), ICU admission, and overall met EAST criteria. Conclusion All RTs performed at our Level 1 trauma center met indications provided by EAST criteria. WTA guidelines were not applicable in nine salvaging encounters due to the protracted duration of CPR before proceeding to RT. Furthermore, more patients that survived to OR and ICU admission met EAST guidelines suggesting an improved potential for patient survivability. As increased data is derived, management guidelines will likely be re-established for optimized patient outcomes.

Pervasive gene flow despite strong and varied reproductive barriers in swordtails.

One of the mechanisms that can lead to the formation of new species occurs through the evolution of reproductive barriers. However, recent research has demonstrated that hybridization has been pervasive across the tree of life even in the presence of strong barriers. Swordtail fishes (genus Xiphophorus) are an emerging model system for studying the interface between these barriers and hybridization. We document overlapping mechanisms that act as barriers between closely related species, X. birchmanni and X. cortezi, by combining genomic sequencing from natural hybrid populations, artificial crosses, behavioral assays, sperm performance, and developmental studies. We show that strong assortative mating plays a key role in maintaining subpopulations with distinct ancestry in natural hybrid populations. Lab experiments demonstrate that artificial F1 crosses experience dysfunction: crosses with X. birchmanni females were largely inviable and crosses with X. cortezi females had a heavily skewed sex ratio. Using F2 hybrids we identify several genomic regions that strongly impact hybrid viability. Strikingly, two of these regions underlie genetic incompatibilities in hybrids between X. birchmanni and its sister species X. malinche. Our results demonstrate that ancient hybridization has played a role in the origin of this shared genetic incompatibility. Moreover, ancestry mismatch at these incompatible regions has remarkably similar consequences for phenotypes and hybrid survival in X. cortezi × X. birchmanni hybrids as in X. malinche × X. birchmanni hybrids. Our findings identify varied reproductive barriers that shape genetic exchange between naturally hybridizing species and highlight the complex evolutionary outcomes of hybridization.

A lethal mitonuclear incompatibility in complex I of natural hybrids.

The evolution of reproductive barriers is the first step in the formation of new species and can help us understand the diversification of life on Earth. These reproductive barriers often take the form of hybrid incompatibilities, in which alleles derived from two different species no longer interact properly in hybrids1-3. Theory predicts that hybrid incompatibilities may be more likely to arise at rapidly evolving genes4-6 and that incompatibilities involving multiple genes should be common7,8, but there has been sparse empirical data to evaluate these predictions. Here we describe a mitonuclear incompatibility involving three genes whose protein products are in physical contact within respiratory complex I of naturally hybridizing swordtail fish species. Individuals homozygous for mismatched protein combinations do not complete embryonic development or die as juveniles, whereas those heterozygous for the incompatibility have reduced complex I function and unbalanced representation of parental alleles in the mitochondrial proteome. We find that the effects of different genetic interactions on survival are non-additive, highlighting subtle complexity in the genetic architecture of hybrid incompatibilities. Finally, we document the evolutionary history of the genes involved, showing signals of accelerated evolution and evidence that an incompatibility has been transferred between species via hybridization.

Effectiveness of Sublingual Buprenorphine for Pain Control in the ICU.

OBJECTIVES: The objective of this study was to compare pain control and opioid consumption in critically ill patients who were treated with buprenorphine sublingual or oxycodone oral/enteral during ICU admission. DESIGN: This was a retrospective, parallel, cohort study. SETTING: General medical or surgical ICUs of a quaternary, urban hospital in Sydney, NSW, Australia. PATIENTS: Data were obtained for all patients admitted to two general medical or surgical ICU from January 2019 to January 2023. Patients were grouped as those who received buprenorphine sublingual versus oxycodone oral/enteral. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pain control was compared between a propensity score matched cohort of patients who received buprenorphine versus oxycodone. The primary outcome was the probability of significant pain. A significant pain score was defined as greater than or equal to 4 on the 0-10 Numeric Rating Scale or greater than or equal to 6 on the Behavioral Pain Scale. The study cohort included 1,070 patients (288 buprenorphine and 782 oxycodone). After propensity score matching, there were 288 patients in each group. The mean age of the matched cohort was 64 ± 16 years, 295 (51%) were male, and 359 (62%) had a surgical admission. The median probability of significant pain was 0.16 with buprenorphine and 0.17 with oxycodone (median difference, 0.01; 95% CI, -0.02 to 0.04; p = 0.50). Median opioid consumption in oral morphine milligram equivalents (MMEs) was 65 with buprenorphine and 70 with oxycodone (median difference, -1 mg; 95% CI, -10 to 10 mg; p = 0.73). Median MME per ICU day was 22 with buprenorphine and 22 with oxycodone (median difference, 1 mg; 95% CI, -2 to 5 mg; p = 0.38). CONCLUSIONS: Buprenorphine sublingual is as effective as oxycodone oral/enteral with regard to pain control and opioid consumption in the ICU. Buprenorphine sublingual is an appropriate option for patients in the ICU who are unable to take oral/enteral medications.

A Statewide Analysis of Self-Inflicted Injuries During COVID-19 Pandemic: Is There Adequate Access to Mental Health?

INTRODUCTION: Many social and behavioral changes occurred during the COVID-19 pandemic. Our objective was to identify changes in incidence of self-inflicted injuries during COVID-19 compared to prepandemic years. Further, we aimed to identify risk factors associated with self-inflicted injuries before and during the pandemic. METHODS: A retrospective cohort study of patients aged ≥18 y with self-inflicted injuries from 2018 to 2021 was performed using the Pennsylvania Trauma Outcome Study registry. Patients were grouped into pre-COVID Era (pre-CE, 2018-2019) and COVID Era (CE, 2020-2021). Statistical comparisons were accomplished using Wilcoxon rank-sum tests and chi-square or Fisher's exact tests. RESULTS: There were a total of 1075 self-inflicted injuries in the pre-CE cohort and 482 during the CE. There were no differences in age, gender, race or ethnicity between the two cohorts. Among preexisting conditions, those within the pre-CE cohort had a higher incidence of mental/personality disorder (59.2% versus 52.3%, P = 0.01). There were no significant differences in the mechanism of self-inflicted injuries or place of injury between the two periods. Additionally, there were no differences in discharge destinations or mortality between the two cohorts. CONCLUSIONS: During the height of social isolation in Pennsylvania, there were no associated increases in self-inflicted injuries. However, there were increased incidences of self-inflicted injuries among those with a prior diagnosis of mental or personality disorder in the pre-CE group. Further investigations are required to study the access to mental health services in future pandemics or public health disasters.

Combination of Lactate and Base Deficit Levels at Admission to Predict Mortality in Blunt Trauma Patients.

INTRODUCTION: Elevated lactate levels are associated with increased mortality in both trauma and non-trauma patients. The relation between base deficit (BD) and mortality is less clear. Traumatologists debate the utility of elevated lactate (EL) versus BD in predicting mortality. We hypothesized that EL (2mmol/L to 5mmol/L) and BD (≤-2mmol/L) in combination could predict mortality in blunt trauma patients.  Methods: This is a retrospective analysis of the trauma registry from 2012 to 2021 at a level 1 trauma center. Blunt trauma patients with admission lactate and BD values were included in the analysis. Exclusion criteria were age <18, penetrating trauma, unknown mortality, and unknown lactate or BD. Logistics regression of the total 5153 charts showed 93% of the patients presented with lactate levels <5mmol/L, therefore patients with lactate >5mmol/L were excluded as outliers. The primary outcome was mortality. RESULTS: A total of 4794 patients (151 non-survivors) were included in the analysis. Non-survivors had higher rates of EL + BD (35.8% vs. 14.4%, p <0.001). When comparing survivors and non-survivors, EL + BD (OR 5.69), age >65 (5.17), injury severity score (ISS) >25 (8.87), Glasgow coma scale <8 (8.51), systolic blood pressure (SBP) <90 (4.2), and ICU admission (2.61) were significant predictors of mortality. Other than GCS <8 and ISS >25, EL + BD had the highest odds of predicting mortality. CONCLUSION: Elevated lactate + BD on admission in combination represents a 5.6-fold increase in mortality in blunt trauma patients and can be used to predict a patient's outcome on admission. This combination variable provides an additional early data point to identify patients at elevated risk of mortality at the moment of admission.

Complex hybridization between deeply diverged fish species in a disturbed ecosystem.

Over the past two decades researchers have documented the extent of natural hybridization between closely related species using genomic tools. Many species across the tree of life show evidence of past hybridization with their evolutionary relatives. In some cases, this hybridization is complex-involving gene flow between more than two species. While hybridization is common over evolutionary timescales, some researchers have proposed that it may be even more common in contemporary populations where anthropogenic disturbance has modified a myriad of aspects of the environments in which organisms live and reproduce. Here, we develop a flexible tool for local ancestry inference in hybrids derived from three source populations and describe a complex, recent hybridization event between distantly related swordtail fish lineages (Xiphophorus) and its potential links to anthropogenic disturbance.

Increase in Motor Vehicle Crash Severity: An Unforeseen Consequence of COVID-19.

INTRODUCTION: The 2019 coronavirus (COVID-19) pandemic led to stay-at-home (SAH) orders in Pennsylvania targeted at reducing viral transmission. Limitations in population mobility under SAH have been associated with decreased motor vehicle collisions (MVC) and related injuries, but the impact of these measures on severity of injury remains unknown. The goal of this study is to measure the incidence, severity, and outcomes of MVC-related injuries associated with SAH in Pennsylvania. MATERIALS & METHODS: We conducted a retrospective geospatial analysis of MVCs during the early COVID-19 pandemic using a state-wide trauma registry. We compared characteristics of patients with MVC-related injuries admitted to Pennsylvania trauma centers during SAH measures (March 21-July 31, 2020) with those from the corresponding periods in 2018 and 2019. We also compared incidence of MVCs for each zip code tabulation area (ZCTA) in Pennsylvania for the same time periods using geospatial mapping. RESULTS: Of 15,550 trauma patients treated during the SAH measures, 3486 (22.4%) resulted from MVCs. Compared to preceding years, MVC incidence decreased 10% under SAH measures with no change in mortality rate. However, in ZCTA where MVC incidence decreased, there was a 16% increase in MVC injury severity. CONCLUSIONS: Stay-at-home orders issued in response to the COVID-19 pandemic in Pennsylvania were associated with significant changes in MVC incidence and severity. Identifying such changes may inform resource allocation decisions during future pandemics or SAH events.

Two Urgency Categories, Same Outcome: No Difference After "Therapeutic" vs. "Prophylactic" Fasciotomy.

OBJECTIVES: Fasciotomy to treat or prevent compartment syndromes in patients with truncal or peripheral arterial injuries is a valuable adjunct. The objective of this study was to document the current incidence, indications, and outcomes of below knee fasciotomy in patients with femoropopliteal arterial injuries. METHODS: The PROspective Observational Vascular Injury Treatment registry of the American Association for the Surgery of Trauma was utilized to identify patients undergoing two-incision four-compartment fasciotomy of the leg after repair of a femoropopliteal arterial injury. Outcomes after therapeutic versus prophylactic (surgeon label) fasciotomy were compared as was the technique of closure, that is, primary skin closure or application of a split-thickness skin graft (STSG). RESULTS: From 2013 to 2018, fasciotomy was performed in 158 patients overall, including 95.6% (151/158) at the initial operation. In the group of 139 patients who survived to discharge, fasciotomies were labeled as therapeutic in 58.3% (81/139) and prophylactic in 41.7% (58/139). There were no significant differences between the therapeutic and prophylactic groups in amputation rates (14.8% vs. 8.6%, P = .919). Primary skin closure was achieved at a median of 5.0 days vs. 11.0 days for STSG (P = .001). CONCLUSIONS: Over 55% of patients undergoing repair of an injury to a femoral or popliteal artery have a fasciotomy performed at the same operation. A "therapeutic" indication for fasciotomy continues to be more common than "prophylactic," while outcomes are identical in both groups.

Laparoscopic Cholecystectomy in the Time of Coronavirus: A Level-1 Trauma Center's Experience.

INTRODUCTION: Laparoscopic cholecystectomy (LC), one of the most common surgical procedures performed in the U.S., offers a window into the effects of the COVID-19 pandemic on routine surgical care. The purpose of our study was to analyze the effects of the COVID-19 pandemic at a Level-1 trauma center on the performance rate of non-elective LC over time. METHODS: A retrospective chart review from July 2019 to December 2020 identified all non-elective LC cases performed at a level-1 trauma center. Patients were categorized into 4 temporal phases along the course of the pandemic based on statewide incidence data on COVID-19: pre-pandemic, peak 1, recovery, and peak 2. We compared the phases based on demographic information and outcomes. RESULTS: In total, 176 patients were reviewed. The performance rate in cases/day varied as follows: pre-pandemic .61, 1st peak .34, recovery .44, and 2nd peak .53. The complication rate was highest in the 2nd peak (16%) (P < .05). Compared to the pre-pandemic period, the intra-pandemic period had a higher incidence of complicated gallbladder disease (P < .05). In the non-elderly subgroup, complicated gallbladder disease was significantly more prevalent in the intra-pandemic period compared to the pre-pandemic period (25% vs 10%, P < .05). CONCLUSIONS: Our data suggests a learning curve throughout the course of the pandemic, reflecting a stepwise increase in the performance rate of LC. The higher incidence of complicated gallbladder disease in the intra-pandemic period may imply patient hesitancy to seek routine surgical care, especially among younger patients.

More than Means to an End: Assessing Surgical Provider Familiarity with Palliative Care.

BACKGROUND: As palliative medicine concepts emerge as essential surgical education, there has been a resulting spike in surgical palliative care research. Historic surgical dogma viewed mortality and comfort-focused care as a failure of the providers' endurance, knowledge base, or technical skill. Therefore, many providers avoided consultation to a palliative medicine service until it became evident a patient could not survive or was actively dying. As the need for surgical palliative care grows, the identification of deficits in surgical providers' understanding of the scope of palliative medicine is necessary to direct further training and development efforts. METHOD: A ten-question survey was emailed to all residents, physician assistants, nurse practitioners, and attending physicians in the general surgery and subspecialty surgical departments within the Einstein Healthcare Network. RESULTS: 30 non-trainees (attending surgeons, nurse practitioners, and physician assistants) and 26 trainees (PGY-1 to PGY-5) completed the survey. Less than half of participants reported training in conversations regarding withdrawal of life-prolonging treatments in the setting of expected poor outcomes, 55% reported receiving training in pain management, and 64% reported receiving training in delivery of bad news. 54% report being involved in five or more end-of-life discussions in the last year with trainees reporting fewer end-of-life discussions than non-trainees; 67% of trainees reported zero to four discussions while 23% of non-trainees reported over twenty discussions (P = .009). CONCLUSIONS: Despite many participants training in intensive care settings, providers lack the training to carry out major discussions regarding life-limiting illness, goals of care, and end-of-life independently.

Effectiveness of Transdermal Buprenorphine for Pain Control in the ICU After Major Surgical Procedures.

Transdermal buprenorphine (TBUP) may be useful for postoperative pain after major surgery, when pain is expected to be severe and sustained. The objective of this study was to compare pain control and opioid consumption in critically ill postoperative patients who were treated with TBUP or not during ICU admission. DESIGN: This was a retrospective, parallel, cohort study. SETTING: ICU of a quaternary, urban hospital in Sydney, Australia. PATIENTS: Data were obtained for all patients admitted to the ICU from January 2019 to July 2021 after major gastrointestinal (GI) or genitourinary (GU) surgery. INTERVENTIONS: TBUP or non-TBUP. MEASUREMENTS AND MAIN RESULTS: Pain control was compared between patients who received TBUP and those who did not receive TBUP. The primary outcome was the probability of significant pain. A significant pain score was defined as greater than or equal to 4 on the 0-10 numeric rating scale or greater than or equal to 6 on the behavioral pain scale. Inverse probability of treatment weighting was used to adjust for baseline differences. The cohort included 376 patients, with 224 (60%) in the control group and 152 (40%) in the TBUP group. The mean age was 60 ± 14 years, 202 (54%) were male, mean Acute Physiology and Chronic Health Evaluation III score was 44 ± 13, and 147 (39%) received mechanical ventilation. After adjustment, the median probability of significant pain was 0.25 with control and 0.30 with TBUP (median difference, 0.02; 95% CI, 0.04-0.11; p = 0.44). The median opioid consumption (oral morphine milligram equivalents) per day was 5.7 mg with control and 10.1 mg with TBUP (median difference, 0.4 mg; 95% CI, -0.4 to 3.7 mg; p = 0.31). CONCLUSIONS: In patients who are admitted to the ICU after major GI or GU procedures, the use of TBUP in the ICU was not associated with improved pain control or opioid consumption compared with those who did not receive TBUP.

Impact of Repeat Head Computed Tomography on Mild Traumatic Brain Injury Patients With Abbreviated Injury Score 1-2 Injuries.

BACKGROUND: Patients presenting with traumatic intracranial hemorrhage (ICH) routinely undergo repeat head Computed Tomography (CT) scans with the goal of identifying progressing hemorrhage early and providing timely intervention. Glasgow Coma Scale (GCS) score and Abbreviated Injury Score (AIS) are typically used to grade the severity of traumatic brain injury (TBI) and triage subsequent management. However, most patients receive a repeat head CT scan within 6 hours of the initial insult, regardless of these clinical scores. We investigated the yield of a repeat CT scan for mild blunt TBI (GCS 13-15, AIS 1-2). METHODS: This was a single-center retrospective chart review at a level 1 trauma center between 2009 and 2019. Our primary outcome was medical or surgical intervention directly resulted from change in CT head findings. We used multivariate regression to identify predictors of surgical and medical intervention. RESULTS: 234 mild TBI patients met inclusion criteria. 33.7% of all patients had worsening ICH. 7.7% of patients required a surgical intervention, and 27.4% received a medical intervention. Multivariate analysis found that a decline in GCS (OR 8.64), and polytrauma (Injury Severity Score >15; OR 3.32) predicted surgical intervention. Worsening ICH did not predict surgical or medical intervention. Patients requiring medical intervention were more likely to have a decline in GCS (OR 2.53, P = .02) and be older (age >65, OR 2.06, P = .02). CONCLUSION: In the population of blunt traumatic injury, worsening ICH did not predict surgical or medical intervention. Routine repeat imaging for this population is low yield, and clinical exam should guide the decision to reimage.

The complications of opioid use during and post-intensive care admission: A narrative review.

Opioids are a commonly administered analgesic medication in the intensive care unit, primarily to facilitate invasive mechanical ventilation. Consensus guidelines advocate for an opioid-first strategy for the management of acute pain in ventilated patients. As a result, these patients are potentially exposed to high opioid doses for prolonged periods, increasing the risk of adverse effects. Adverse effects relevant to these critically ill patients include delirium, intensive care unit-acquired infections, acute opioid tolerance, iatrogenic withdrawal syndrome, opioid-induced hyperalgesia, persistent opioid use, and chronic post-intensive care unit pain. Consequently, there is a challenge of optimising analgesia while minimising these adverse effects. This narrative review will discuss the characteristics of opioid use in the intensive care unit, outline the potential short-term and long-term adverse effects of opioid therapy in critically ill patients, and outline a multifaceted strategy for opioid minimisation.

Pain assessment and analgesic management in patients admitted to intensive care: an Australian and New Zealand point prevalence study.

Objective: To describe pain assessment and analgesic management practices in patients in intensive care units (ICUs) in Australia and New Zealand. Design, setting and participants: Prospective, observational, multicentre, single-day point prevalence study conducted in Australian and New Zealand ICUs. Observational data were recorded for all adult patients admitted to an ICU without a neurological, neurosurgical or postoperative cardiac diagnosis. Demographic characteristics and data on pain assessment and analgesic management for a 24-hour period were collected. Main outcome measures: Types of pain assessment tools used and frequency of their use, use of opioid analgesia, use of adjuvant analgesia, and differences in pain assessment and analgesic management between postoperative and non-operative patients. Results: From the 499 patients enrolled from 45 ICUs, pain assessment was performed at least every 4 hours in 56% of patients (277/499), most commonly with a numerical rating scale. Overall, 286 patients (57%) received an opioid on the study day. Of the 181 mechanically ventilated patients, 135 (75%) received an intravenous opioid, with the predominant opioid infusion being fentanyl. The median dose of opioid infusion for ventilated patients was 140 mg oral morphine equivalents. Of the 318 non-ventilated patients, 41 (13%) received patient-controlled analgesia and 76 (24%) received an oral opioid, with the predominant opioid being oxycodone. Paracetamol was administered to 63 ventilated patients (35%) and 164 non-ventilated patients (52%), while 2% of all patients (11/499) received a non-steroidal anti-inflammatory drug. Ketamine infusion and regional analgesia were used in 15 patients (3%) and 17 patients (3%), respectively. Antineuropathic agents (predominantly gabapentinoids) were used in 53 patients (11%). Conclusions: Although a majority of ICU patients were frequently assessed for pain with a validated pain assessment tool, cumulative daily doses of opioids were high, and the use of multimodal adjuvant analgesia was low. Our data on current pain assessment and analgesic management practices may inform further research in this area.

Insurance Status Impacts Hospital Discharge for Penetrating Trauma Survivors.

BACKGROUND: Despite equalized acute care in trauma, disparities exist in the long-term outcomes of trauma survivors. Prior studies have revealed insurance status plays a role in the discharge destination of blunt trauma survivors. This is yet to be described in patients with penetrating traumatic injury. METHODS: A retrospective chart review from 2009 to 2019 from an urban Level 1 trauma center identified adult patients who survived penetrating trauma to discharge. Patients were categorized by insurance status. Patient demographics, discharge destination, and hospital length of stay (LOS) were analyzed using the t-test and ANOVA. RESULTS: 1806 patients were identified with 1410 survivors to hospital discharge. Among the survivors, 26.8% were uninsured, 13.1% were privately insured, and 60.0% had Medicare/Medicaid. The uninsured patients were significantly less likely to be discharged to a rehabilitation facility or skilled nursing facility (OR = .49, 95% CI .35-.71) compared to the insured patients. Uninsured survivors had shorter LOS compared to the other groups (5.8 vs. 7.3, P < .01.) Severity of injury did not significantly influence the discharge destination or LOS between the groups. CONCLUSION: Despite recent health care reform, many trauma patients remain uninsured. Our study shows that uninsured penetrating trauma survivors are less likely to be discharged to rehabilitation and skilled nursing facilities. This may contribute to uninsured trauma survivors not receiving appropriate post-traumatic care and could lead to the accrual of undue disability, long-term complications, and increased societal burdens.

Two new hybrid populations expand the swordtail hybridization model system.

Natural hybridization events provide unique windows into the barriers that keep species apart as well as the consequences of their breakdown. Here, we characterize hybrid populations formed between the northern swordtail fish Xiphophorus cortezi and Xiphophorus birchmanni from collection sites on two rivers. We use simulations and new genetic reference panels to develop sensitive and accurate local ancestry calling in this novel system. Strikingly, we find that hybrid populations on both rivers consist of two genetically distinct subpopulations: a cluster of pure X. birchmanni individuals and one of phenotypically intermediate hybrids that derive ∼85-90% of their genome from X. cortezi. Simulations suggest that initial hybridization occurred ∼150 generations ago at both sites, with little evidence for contemporary gene flow between subpopulations. This population structure is consistent with strong assortative mating between individuals of similar ancestry. The patterns of population structure uncovered here mirror those seen in hybridization between X. birchmanni and its sister species, Xiphophorus malinche, indicating an important role for assortative mating in the evolution of hybrid populations. Future comparisons will provide a window into the shared mechanisms driving the outcomes of hybridization not only among independent hybridization events between the same species but also across distinct species pairs.

The genomic consequences of hybridization.

In the past decade, advances in genome sequencing have allowed researchers to uncover the history of hybridization in diverse groups of species, including our own. Although the field has made impressive progress in documenting the extent of natural hybridization, both historical and recent, there are still many unanswered questions about its genetic and evolutionary consequences. Recent work has suggested that the outcomes of hybridization in the genome may be in part predictable, but many open questions about the nature of selection on hybrids and the biological variables that shape such selection have hampered progress in this area. We synthesize what is known about the mechanisms that drive changes in ancestry in the genome after hybridization, highlight major unresolved questions, and discuss their implications for the predictability of genome evolution after hybridization.