Determinants and practice variability of oxygen administration during surgery in the U.S., a retrospective cohort study.

BACKGROUND: The best approaches to supplemental oxygen administration during surgery remain unclear, which may contribute to variation in practice. We aimed to assess determinants of oxygen administration and its variability during surgery. METHODS: Using multivariable linear mixed-effects regression, we measured the associations between intraoperative fraction of inspired oxygen and patient, procedure, medical center, anesthesiologist, and in-room anesthesia provider factors in surgical cases of 120 minutes or longer in adult patients who received general anesthesia with tracheal intubation and were admitted to the hospital after surgery between January 2016 and January 2019 at 42 medical centers across the U.S. participating in the Multicenter Perioperative Outcomes Group data registry. RESULTS: The sample included 367,841 cases (median [25 th, 75 th] age, 59 [47, 69] years; 51.1% women; 26.1% treated with nitrous oxide) managed by 3,836 anesthesiologists and 15,381 in-room anesthesia providers. Median (25 th, 75 th) fraction of inspired oxygen was 0.55 (0.48, 0.61), with 6.9% of cases <0.40 and 8.7% >0.90. Numerous patient and procedure factors were statistically associated with increased inspired oxygen, notably advanced ASA classification, heart disease, emergency surgery, and cardiac surgery, but most factors had little clinical significance (<1% inspired oxygen change). Overall, patient factors only explained 3.5% (95% CI, 3.5 to 3.5) of the variability in oxygen administration and procedure factors 4.4% (4.2 to 4.6). Anesthesiologist explained 7.7% (7.2 to 8.2) of the variability in oxygen administration, in-room anesthesia provider 8.1% (7.8 to 8.4), medical center 23.3% (22.4 to 24.2), and 53.0% (95% CI, 52.4 to 53.6) was unexplained. CONCLUSIONS: Among adults undergoing surgery with anesthesia and tracheal intubation, supplemental oxygen administration was variable and appeared arbitrary. Most patient and procedure factors had statistical but minor clinical associations with oxygen administration. Medical center and anesthesia provider explained significantly more variability in oxygen administration than patient or procedure factors.

Data-Driven Blood Transfusion Thresholds for Severely Injured Patients During Blood Shortages.

INTRODUCTION: Crises like the COVID-19 pandemic create blood product shortages. Patients requiring transfusions are placed at risk and institutions may need to judiciously administer blood during massive blood transfusions protocols (MTP). The purpose of this study is to provide data-driven guidance for the modification of MTP when the blood supply is severely limited. METHODS: This is a retrospective cohort study of 47 Level I and II trauma centers (TC) within a single healthcare system whose patients received MTP from 2017 to 2019. All TC used a unifying MTP protocol for balanced blood product transfusions. The primary outcome was mortality as a function of volume of blood transfused and age. Hemoglobin thresholds and measures of futility were also estimated. Risk-adjusted analyses were performed using multivariable and hierarchical regression to account for confounders and hospital variation. RESULTS: Proposed MTP maximum volume thresholds for three age groupings are as follows: 60 units for ages 16-30 y, 48 units for ages 31-55 y, and 24 units for >55 y. The range of mortality under the transfusion threshold was 30%-36% but doubled to 67-77% when the threshold was exceeded. Hemoglobin concentration differences relative to survival were clinically nonsignificant. Prehospital measures of futility were prehospital cardiac arrest and nonreactive pupils. In hospital risk factors of futility were mid-line shift on brain CT and cardiopulmonary arrest. CONCLUSIONS: Establishing MTP threshold practices under blood shortage conditions, such as the COVID pandemic, could sustain blood availability by following relative thresholds for MTP use according to age groups and key risk factors.

The burden of geriatric traumatic brain injury on trauma systems: Analysis of 348,800 Medicare inpatient claims.

BACKGROUND: Traumatic brain injury (TBI) is a leading cause of death and disability in older adults. The aim of this study was to characterize the burden of TBI in older adults by describing demographics, care location, diagnoses, outcomes, and payments in this high-risk group. METHODS: Using 2016-2019 Centers for Medicare & Medicaid Services (CMS) Inpatient Standard Analytical Files (IPSAF), patients >65 years with TBI (>1 injury ICD-10 starting with "S06") were selected. Trauma center levels were linked to the IPSAF file via American Hospital Association Hospital Provider ID and fuzzy-string matching. Patient variables were compared across trauma center levels. RESULTS: Three hundred forty-eight thousand eight hundred inpatients (50.4% female; 87.1% white) from 2963 US hospitals were included. Level I/II trauma centers treated 66.9% of patients; non-trauma centers treated 21.5%. Overall inter-facility transfer rate was 19.2%; in Level I/II trauma centers transfers-in represented 23.3% of admissions. Significant TBI (Head AIS ≥3) was present in 70.0%. Most frequent diagnoses were subdural hemorrhage (56.6%) and subarachnoid hemorrhage (30.6%). Neurosurgical operations were performed in 10.9% of patients and operative rates were similar regardless of center level. Total unadjusted mortality for the sample was 13.9%, with a mortality of 8.1% for those who expired in-hospital, and an additional 5.8% for those discharged to hospice. Medicare payments totaled $4.91B, with the majority (73.4%) going to Level I/II trauma centers. CONCLUSIONS: This study fills a gap in TBI research by demonstrating that although the majority of older adult TBI patients in the United States receive care at Level I/II trauma centers, a substantial percentage are managed at other facilities, despite 1 in 10 requiring neurosurgical operation regardless of level of trauma center. This analysis provides preliminary data on the function of regionalized trauma care for older adult TBI care. Future studies assessing the efficacy of early care guidelines in this population are warranted.

Low Prevalence but High Impact of COVID-19 Positive Status in Adult Trauma Patients: A Multi-institutional Analysis of 28 904 Patients.

BACKGROUND: Few large investigations have addressed the prevalence of COVID-19 infection among trauma patients and impact on providers. The purpose of this study was to quantify the prevalence of COVID-19 infection among trauma patients by timing of diagnosis, assess nosocomial exposure risk, and evaluate the impact of COVID-19 positive status on morbidity and mortality. METHODS: Registry data from adults admitted 4/1/2020-10/31/2020 from 46 level I/II trauma centers were grouped by: timing of first positive status (Day 1, Day 2-6, or Day ≥ 7); overall Positive/Negative status; or Unknown if test results were unavailable. Groups were compared on outcomes (Trauma Quality Improvement Program complications) and mortality using univariate analysis and adjusted logistic regression. RESULTS: There were 28 904 patients (60.7% male, mean age: 56.4, mean injury severity score: 10.5). Of 13 274 (46%) patients with known COVID-19 status, 266 (2%) were Positive Day 1, 119 (1%) Days 2-6, 33 (.2%) Day ≥ 7, and 12 856 (97%) tested Negative. COVID-19 Positive patients had significantly worse outcomes compared to Negative; unadjusted comparisons showed longer hospital length of stay (10.98 vs 7.47;P < .05), higher rates of intensive care unit (57.7% vs 45.7%; P < .05) and ventilation use (22.5% vs 16.9%; P < .05). Adjusted comparisons showed higher rates of acute respiratory distress syndrome (1.7% vs .4%; P < .05) and death (8.1% vs 3.4%; P < .05). CONCLUSIONS: This multicenter study conducted during the early pandemic period revealed few trauma patients tested COVID-19 positive, suggesting relatively low exposure risk to care providers. COVID-19 positive status was associated with significantly higher mortality and specific morbidity. Further analysis is needed with consideration for care guidelines specific to COVID-19 positive trauma patients as the pandemic continues.

Bacteremia in Trauma: A Contemporary Analysis of Blood Culture Results and Outcomes in 158,884 Patients.

Background: Bacteremia is a potentially lethal complication. Limited research exists describing its incidence and associated outcomes in trauma patients. This descriptive study characterized the incidence, risk factors, and outcomes of bacteremia in trauma patients. Methods: This study used 2017-2020 system-wide Trauma Registry/Electronic Data Warehouse to select trauma activations aged ≥18 years. Blood culture information, including pathogen genera and species, was obtained from electronic laboratory records. Bacteremia positive was defined as two blood cultures within two hours of each other, growing the same organism; bacteremia negative as no growth, only one blood culture with growth, or growth of two different organisms. Bacteremia-positive and bacteremia-negative patients were compared with patients without blood cultures. Logistic regression compared blood culture results with outcomes, adjusting for age, gender, Injury Severity Score (ISS), and comorbidities. Results: Of 158,884 patients at 89 centers, 17,166 (10.8%) had blood cultures. Of those with blood cultures, 1214 were bacteremia positive (7.1%). Compared with no blood cultures, bacteremia-positive patients were more likely male, with higher ISS, and more comorbidities and intensive care unit use. Bacteremia-positive patients were more likely to die (adjusted odds ratio [aOR], 3.78; 95% confidence interval [CI], 3.17-4.51; p < 0.001) and have severe sepsis/septic shock (aOR, 114.91; 95% CI, 95.09-138.85; p < 0.001). Most common isolates were Staphylococcus epidermidis (14%), non-methicillin resistant Staphylococcus aureus (12%), and Escherichia coli (6%), with highest mortality associated with Pseudomonas aeruginosa (45%), Enterococcus faecalis (30%), and Escherichia coli (28%). Conclusions: Bacteremia in trauma is uncommon (<1%) but associated with increased resource use and poorer outcomes. Bacteremia, or suspicion thereof, identifies a high-risk population and justifies aggressive empiric intervention to maximize survival.

What Makes a Trauma Patient "Pediatric"? Survey of Providers' Admission Decision Making for Pediatric Trauma Patients.

BACKGROUND: Only a fraction of pediatric trauma patients are treated in pediatric-specific facilities, leaving the remaining to be seen in centers that must decide to admit the patient to a pediatric or adult unit. Thus, there may be inconsistencies in pediatric trauma admission practices among trauma centers. OBJECTIVE: Describe current practices in admission decision making for pediatric patients. METHODS: An email survey was distributed to members of three professional organizations: The American Association for the Surgery of Trauma, Society of Trauma Nurses, and Pediatric Trauma Society. The survey contained questions regarding pediatric age cutoffs, institutional placement decisions, and scenario-based assessments to determine mitigating placement factors. RESULTS: There were 313 survey responses representing freestanding children's hospitals (114, 36.4%); children's hospitals within general hospitals (107, 34.2%), and adult centers (not a children's hospital; 90, 28.8%). The mean age cutoff for pediatric admission was 16.6 years. The most reported cutoff ages were 18 years (77, 25.6%) and 15 years (76, 25.2%). The most common rationales for the age cutoffs were "institutional experience/tradition" (139, 44.4%) and "physician preference" (89, 28.4%). CONCLUSION: There was no single widely accepted age cutoff that distinguished pediatric from adult trauma patients for admission placement. There was significant variability between and within the types of facilities, with noted ambiguity in the definition of a "pediatric" patient. Thresholds appear to be based primarily on subjective criteria such as traditions or preferences rather than scientific data. Institutions should strive for objective, evidence-based policies for determining the appropriate placement of pediatric patients.

Trauma Prevalence and Resource Utilization During 4 COVID-19 "Surges": A National Analysis of Trauma Patients From 92 Trauma Centers.

INTRODUCTION: We aim to assess the trends in trauma patient volume, injury characteristics, and facility resource utilization that occurred during four surges in COVID-19 cases. METHODS: A retrospective cohort study of 92 American College of Surgeons (ACS)-verified trauma centers (TCs) in a national hospital system during 4 COVID-19 case surges was performed. Patients who were directly transported to the TC and were an activation or consultation from the emergency department (ED) were included. Trends in injury characteristics, patient demographics & outcomes, and hospital resource utilization were assessed during four COVID-19 case surges and compared to the same dates in 2019. RESULTS: The majority of TCs were within a metropolitan or micropolitan division. During the pandemic, trauma admissions decreased overall, but displayed variable trends during Surges 1-4 and across U.S. regions and TC levels. Patients requiring surgery or blood transfusion increased significantly during Surges 1-3, whereas the proportion of patients requiring plasma and/or platelets increased significantly during Surges 1-2. Patients admitted to the hospital had significantly higher Injury Severity Score (ISS) and mortality as compared to pre-pandemic during Surge 1 and 2. Patients with Medicaid or uninsured increased significantly during the pandemic. Hospital length of stay (LOS) decreased significantly during the pandemic and more trauma patients were discharged home. CONCLUSIONS: Trauma admissions decreased during Surge 1, but increased during Surge 2, 3 and 4. Penetrating injuries and firearm-related injuries increased significantly during the pandemic, patients requiring surgery or packed red blood cells (PRBCs) transfusion increased significantly during Surges 1-3. The number of patients discharged home increased during the pandemic and was accompanied by a decreased hospital length of stay (LOS).

Hyperglycemia in nondiabetic adult trauma patients is associated with worse outcomes than diabetic patients: An analysis of 95,764 patients.

BACKGROUND: The adverse impact of acute hyperglycemia is well documented but its specific effects on nondiabetic trauma patients are unclear. The purpose of this study was to analyze the differential impact of hyperglycemia on outcomes between diabetic and nondiabetic trauma inpatients. METHODS: Adults admitted 2018 to 2019 to 46 Level I/II trauma centers with two or more blood glucose tests were analyzed. Diabetes status was determined from International Classification of Diseases-10th Rev.-Clinical Modification, trauma registry, and/or hemoglobin A1c greater than 6.5. Patients with and without one or more hyperglycemic result >180 mg/dL were compared. Logistic regression examined the effects of hyperglycemia and diabetes on outcomes, adjusting for age, sex, Injury Severity Score, and body mass index. RESULTS: There were 95,764 patients: 54% male; mean age, 61 years; mean Injury Severity Score, 10; diabetic, 21%. Patients with hyperglycemia had higher mortality and worse outcomes compared with those without hyperglycemia. Nondiabetic hyperglycemic patients had the highest odds of mortality (diabetic: adjusted odds ratio, 3.11; 95% confidence interval, 2.8-3.5; nondiabetics: adjusted odds ratio, 7.5; 95% confidence interval, 6.8-8.4). Hyperglycemic nondiabetics experienced worse outcomes on every measure when compared with nonhyperglycemic nondiabetics, with higher rates of sepsis (1.1 vs. 0.1%, p < 0.001), more SSIs (1.0 vs. 0.1%, p < 0.001), longer mean hospital length of stay (11.4 vs. 5.0, p < 0.001), longer mean intensive care unit length of stay (8.5 vs. 4.0, p < 0.001), higher rates of intensive care unit use (68.6% vs. 35.1), and more ventilator use (42.4% vs. 7.3%). CONCLUSION: Hyperglycemia is associated with increased odds of mortality in both diabetic and nondiabetic patients. Hyperglycemia during hospitalization in nondiabetics was associated with the worst outcomes and represents a potential opportunity for intervention in this high-risk group. LEVEL OF EVIDENCE: Therapeutic/care management; Level III.

Poised for Change: University Students Are Positively Disposed toward Food Waste Diversion and Decrease Individual Food Waste after Programming.

Eaters (consumers of food) are responsible for 60% of waste along the food cycle in developed countries. Programs that target individual and household food waste behavior change are essential to addressing such waste. School cafeterias worldwide offer an opportune microcosm in which to educate on food and nutrition skills and change related behavior. No Scrap Left Behind, a cafeteria food waste diversion program, was developed, piloted, and assessed based on measures of both direct and indirect food waste behavior, and attitudes, knowledge, and emotions related to food waste. Participants had positive attitudes towards food waste reduction, engaged in food waste diversion actions, had some knowledge of the impacts of wasted food, and considered their actions important to waste reduction generally. Food waste per student was decreased by 28% over the course of the first year of programming (p = 0.000967), and by 26% in the following year when measured a week before and a week after programming occurred (p = 0.0218). Results indicate that students were poised for food behavior change and that related programming did impact behavior in the short term. Programming may, therefore, help improve student attitudes and skills to develop long-term change as well, although future research should explore this specifically. In comparison with other research on cafeteria programming, results suggest that food waste diversion programming can positively impact students' dispositions and behaviors, and may be more effective when tailored to the specific population.

Redefining geriatric trauma: 55 is the new 65.

INTRODUCTION: As the prevalence of geriatric trauma patients has increased, protocols are being developed to address the unique requirements of this demographic. However, categorical definitions for geriatric patients vary, potentially creating confusion concerning which patients should be cared for according to geriatric-specific standards. The aim of this study was to identify data-driven cut points for mortality based on age to support implementation of age-driven guidelines. METHODS: Adults aged 18 to 100 years with blunt or penetrating injury were selected from 95 hospitals' trauma registries. Change point analysis techniques were used to detect inflection points in the proportion of deaths at each age. Based on these calculated points, patients were allocated into age groups, and their characteristics and outcomes were compared. Logistic regression was used to estimate risk-adjusted in-hospital mortality controlling for sex, race, Injury Severity Score, Glasgow Coma Scale, and number of comorbidities. RESULTS: A total of 255,099 patients were identified (female, 45.7%; mean age, 59.3 years; mean Injury Severity Score, 8.69; blunt injury, 92.6%). Statistically significant increases in mortality rate were noted at ages 55, 77, and 82 years. Compared with the referent group (age, <55 years), adjusted odds ratios (AORs) showed increases in mortality if age 55 to 76 years (AOR, 2.42), age 77 to 81 years (AOR, 4.70), or age 82 years or older (AOR, 6.43). National Trauma Data Standard-defined comorbidities significantly increased once age surpassed 55 years, as the rate more than doubled for each of the older age categories (p < 0.001). As age increased, each group was more likely to be female, have dementia, sustain a ground level fall, and be discharged to a skilled nursing facility (p < 0.001). CONCLUSION: This large multicenter analysis established a clinically and statistically significant increase in mortality at ages 55, 77, and 82 years. This research strongly suggests that trauma patients older than 55 years be considered for inclusion in geriatric trauma protocols. The other age inflection points identified (77 and 82 years) may also warrant additional specialized care considerations. LEVEL OF EVIDENCE: Epidemiological study, level III; Care management, level IV.

Decreased adult trauma admission volumes and changing injury patterns during the COVID-19 pandemic at 85 trauma centers in a multistate healthcare system.

BACKGROUND: Reports indicate social distancing guidelines and other effects of the COVID-19 pandemic impacted trauma patient volumes and injury patterns. This report is the first analysis of a large trauma network describing the extent of these impacts. The objective of this study was to describe the effects of the COVID-19 pandemic on patient volumes, demographics, injury characteristics, and outcomes. METHODS: For this descriptive, multicenter study from a large, multistate hospital network, data were collected from the system-wide centralized trauma registry and retrospectively reviewed to retrieve patient information including volume, demographics, and outcomes. For comparison, patient data from January through May of 2020 and January through May of 2019 were extracted. RESULTS: A total of 12 395 trauma patients (56% men, 79% white, mean age 59 years) from 85 trauma centers were included. The first 5 months of 2020 revealed a substantial decrease in volume, which began in February and continued into June. Further analysis revealed an absolute decrease of 32.5% in patient volume in April 2020 compared with April 2019 (4997 from 7398; p<0.0001). Motor vehicle collisions decreased 49.7% (628 from 1249). There was a statistically significant increase in injury severity score (9.0 vs. 8.3; p<0.001). As a proportion of the total trauma population, blunt injuries decreased 3.1% (87.3 from 90.5) and penetrating injuries increased 2.7% (10.0 from 7.3; p<0.001). A significant increase was found in the proportion of patients who did not survive to discharge (3.6% vs. 2.8%; p=0.010; absolute decrease: 181 from 207). DISCUSSION: Early phases of the COVID-19 pandemic were associated with a 32.5% decrease in trauma patient volumes and altered injury patterns at 85 trauma centers in a multistate system. This preliminary observational study describes the initial impact of the COVID-19 pandemic and warrants further investigation. LEVEL OF EVIDENCE: Level II (therapeutic/care management).

Increasing BMI is associated with higher mortality, worsening outcomes and highly specific injury patterns following trauma: A multi-institutional analysis of 191,274 patients.

BACKGROUND: As the prevalence of obesity has increased, trauma centers are faced with managing this expanding demographics' unique care requirements. Research on the effects of body mass index (BMI) in trauma patients remains conflicting. This study aims to evaluate the impact of BMI on patterns of injury and patient outcomes following trauma. METHODS: Patients from 87 hospitals' trauma registries were selected. Those missing height, weight, disposition, or who died in the emergency department were excluded. The BMI categories were calculated from admission height and weight and verified against the electronic medical records. Patients were grouped by the National Institutes of Health-defined obesity class and compared by rate of mortality and in-hospital complications. Logistic regression was used to estimate associations, adjusting for age, gender, race, Injury Severity Score, and number of comorbidities. RESULTS: There were 191,274 patients, 53% male; mean age was 60.4 years, mean Glasgow Coma Scale score 14.4, mean Injury Severity Score of 8.8, and 40.4% normal weight. Increased BMI was associated with an injury pattern of increased rates of extremity fractures (humerus, femur, tibia/fibula) and decreased rates of hip fractures and head injuries. Compared with the normal weight group, patients were more likely to die if they were Underweight (adjusted odds ratio [AOR], 1.18; 95% confidence interval [CI], 1.01-1.38), obese class II (AOR, 1.24; 95% CI, 1.07-1.45), or obese class III (AOR, 1.55; 95% CI, 1.29-1.87). Obese class III was associated with higher odds of a National Trauma Data Standard complication (AOR, 1.20; 95% CI, 1.11-1.30). CONCLUSION: In this large multicenter study, increasing BMI and lower than normal BMI were strongly associated with higher mortality. Increasing BMI was also associated with longer length of stay, increased complications, and unique injury patterns. These untoward outcomes, coupled with a distinct injury pattern, warrant care guidelines specific to trauma patients with higher BMI, as well as those with BMI lower than normal. LEVEL OF EVIDENCE: Epidemiological, Level III.

Where Did All the Appendicitis Go? Impact of the COVID-19 Pandemic on Volume, Management, and Outcomes of Acute Appendicitis in a Nationwide, Multicenter Analysis.

Objective: The study objective was to evaluate effects of the COVID-19 pandemic on rates of emergency department (ED) acute appendicitis presentation, management strategies, and patient outcomes. Summary Background Data: Acute appendicitis is the most commonly performed emergency surgery in the United States and is unlikely to improve without medical or surgical intervention. Dramatic reductions in ED visits prompted concern that individuals with serious conditions, such as acute appendicitis, were deferring treatment for fear of contracting COVID-19. Methods: Patients from 146 hospitals with diagnosed appendicitis and arrival between March 2016 and May 2020 were selected. Electronic medical records data were retrospectively reviewed to retrieve patient data. Daily admissions were averaged from March 2016 through May 2019 and compared with March 2020. April-specific admissions were compared across the 5-year pre-COVID-19 period to April 2020 to identify differences in volume, demographics, disease severity, and outcomes. Results: Appendicitis patient admissions in 2020 decreased throughout March into April, with April experiencing the fewest admissions. April 2020 experienced a substantial decrease in patients who presented with appendicitis, dropping 25.4%, from an average of 2030 patients (2016-2019) to 1516 in 2020. An even greater decrease of 33.8% was observed in pediatric patients (age <18). Overall, 77% of the 146 hospitals experienced a reduction in appendicitis admissions. There were no differences between years in percent of patients treated nonoperatively (P = 0.493) incidence of shock (P = 0.95), mortality (P = 0.24), or need for postoperative procedures (P = 0.81). Conclusions: Acute appendicitis presentations decreased significantly during the COVID-19 pandemic, while overall management and patient outcomes did not differ from previous years. Further research is needed focusing on putative explanations for decreased hospital presentations unrelated to COVID-19 infection and possible implications for surgical management of uncomplicated acute appendicitis.Keywords: acute appendicitis, COVID-19, decreasing volumes, multicenter study.

Antiplatelet and anticoagulant agents have minimal impact on traumatic brain injury incidence, surgery, and mortality in geriatric ground level falls: A multi-institutional analysis of 33,710 patients.

BACKGROUND: Falls are the leading cause of traumatic brain injury (TBI) and TBI-related deaths for older persons (age, ≥65 years). Antiplatelet and/or anticoagulant therapy (antithrombotics [ATs]) is generally felt to increase this risk, but the literature is inconsistent. The purpose of this study was to determine the impact of AT use on the rate, severity, and outcomes of TBI in older patients following ground level falls. METHODS: Ground level fall patients from 90 hospitals' trauma registries were selected. Patients were excluded if younger than 65 years or had an Abbreviated Injury Scale score of >2 in a region other than head. Electronic medical record data for preinjury AT therapy were obtained. Patients were grouped by regimen for no AT, single, or multiple agents. Groups were compared on rates of diagnosed TBI, TBI surgery, and mortality. RESULTS: There were 33,710 patients (35% male; mean age, 80.5 years; mean Glasgow Coma Scale, 14.6), with 47.6% on single or combination AT therapy. The proportion of patients with TBI diagnoses did not differ between those on no AT (21.25%) versus AT (21.61%; p = 0.418). Apixaban (15.7%; p < 0.001) and rivaroxaban (13.19%; p = 0.011) were associated with lower rates of TBI, and acetylsalicylic acid-clopidogrel was associated with a higher TBI rate (24.34%; p = 0.002) versus no AT. acetylsalicylic acid-clopidogrel was associated with a higher cranial surgery rate (2.9%; p = 0.006) versus no AT (1.96%), but surgery rates were similar for all other regimens. No regimen was associated with higher mortality. CONCLUSION: In this large multicenter study, the intake of ATs in older patients with ground level falls was associated with inconsistent effects on risk of TBI and no significant increases in mortality, indicating that AT use may have negligible impact on patient clinical management. A large, confirmatory, prospective study is needed because the commonly held belief that ATs uniformly increase the risk of traumatic intracranial bleeding and mortality is not supported. LEVEL OF EVIDENCE: Therapeutic/care management, level II.

Roots Mediate the Effects of Snowpack Decline on Soil Bacteria, Fungi, and Nitrogen Cycling in a Northern Hardwood Forest.

Rising winter air temperature will reduce snow depth and duration over the next century in northern hardwood forests. Reductions in snow depth may affect soil bacteria and fungi directly, but also affect soil microbes indirectly through effects of snowpack loss on plant roots. We incubated root exclusion and root ingrowth cores across a winter climate-elevation gradient in a northern hardwood forest for 29 months to identify direct (i.e., winter snow-mediated) and indirect (i.e., root-mediated) effects of winter snowpack decline on soil bacterial and fungal communities, as well as on potential nitrification and net N mineralization rates. Both winter snowpack decline and root exclusion increased bacterial richness and phylogenetic diversity. Variation in bacterial community composition was best explained by differences in winter snow depth or soil frost across elevation. Root ingrowth had a positive effect on the relative abundance of several bacterial taxonomic orders (e.g., Acidobacterales and Actinomycetales). Nominally saprotrophic (e.g., Saccharomycetales and Mucorales) or mycorrhizal (e.g., Helotiales, Russalales, Thelephorales) fungal taxonomic orders were also affected by both root ingrowth and snow depth variation. However, when grouped together, the relative abundance of saprotrophic fungi, arbuscular mycorrhizal fungi, and ectomycorrhizal fungi were not affected by root ingrowth or snow depth, suggesting that traits in addition to trophic mode will mediate fungal community responses to snowpack decline in northern hardwood forests. Potential soil nitrification rates were positively related to ammonia-oxidizing bacteria and archaea abundance (e.g., Nitrospirales, Nitrosomondales, Nitrosphaerales). Rates of N mineralization were positively and negatively correlated with ectomycorrhizal and saprotrophic fungi, respectively, and these relationships were mediated by root exclusion. The results from this study suggest that a declining winter snowpack and its effect on plant roots each have direct effects on the diversity and abundance of soil bacteria and fungal communities that interact to determine rates of soil N cycling in northern hardwood forests.

Climate and lawn management interact to control C4 plant distribution in residential lawns across seven U.S. cities.

In natural grasslands, C4 plant dominance increases with growing season temperatures and reflects distinct differences in plant growth rates and water use efficiencies of C3 vs. C4 photosynthetic pathways. However, in lawns, management decisions influence interactions between planted turfgrass and weed species, leading to some uncertainty about the degree of human vs. climatic controls on lawn species distributions. We measured herbaceous plant carbon isotope ratios (δ13 C, index of C3 /C4 relative abundance) and C4 cover in residential lawns across seven U.S. cities to determine how climate, lawn plant management, or interactions between climate and plant management influenced C4 lawn cover. We also calculated theoretical C4 carbon gain predicted by a plant physiological model as an index of expected C4 cover due to growing season climatic conditions in each city. Contrary to theoretical predictions, plant δ13 C and C4 cover in urban lawns were more strongly related to mean annual temperature than to growing season temperature. Wintertime temperatures influenced the distribution of C4 lawn turf plants, contrary to natural ecosystems where growing season temperatures primarily drive C4 distributions. C4 cover in lawns was greatest in the three warmest cities, due to an interaction between climate and homeowner plant management (e.g., planting C4 turf species) in these cities. The proportion of C4 lawn species was similar to the proportion of C4 species in the regional grass flora. However, the majority of C4 species were nonnative turf grasses, and not of regional origin. While temperature was a strong control on lawn species composition across the United States, cities differed as to whether these patterns were driven by cultivated lawn grasses vs. weedy species. In some cities, biotic interactions with weedy plants appeared to dominate, while in other cities, C4 plants were predominantly imported and cultivated. Elevated CO2 and temperature in cities can influence C3 /C4 competitive outcomes; however, this study provides evidence that climate and plant management dynamics influence biogeography and ecology of C3 /C4 plants in lawns. Their differing water and nutrient use efficiency may have substantial impacts on carbon, water, energy, and nutrient budgets across cities.

A Survey Evaluating Burnout, Health Status, Depression, Reported Alcohol and Substance Use, and Social Support of Anesthesiologists.

BACKGROUND: Burnout affects all medical specialists, and concern about it has become common in today's health care environment. The gold standard of burnout measurement in health care professionals is the Maslach Burnout Inventory-Human Services Survey (MBI-HSS), which measures emotional exhaustion, depersonalization (DP), and personal accomplishment. Besides affecting work quality, burnout is thought to affect health problems, mental health issues, and substance use negatively, although confirmatory data are lacking. This study evaluates some of these effects. METHODS: In 2011, the American Society of Anesthesiologists and the journal Anesthesiology cosponsored a webinar on burnout. As part of the webinar experience, we included access to a survey using MBI-HSS, 12-item Short Form Health Survey (SF-12), Social Support and Personal Coping (SSPC-14) survey, and substance use questions. Results were summarized using sample statistics, including mean, standard deviation, count, proportion, and 95% confidence intervals. Adjusted linear regression methods examined associations between burnout and substance use, SF-12, SSPC-14, and respondent demographics. RESULTS: Two hundred twenty-one respondents began the survey, and 170 (76.9%) completed all questions. There were 266 registrants total (31 registrants for the live webinar and 235 for the archive event), yielding an 83% response rate. Among respondents providing job titles, 206 (98.6%) were physicians and 2 (0.96%) were registered nurses. The frequency of high-risk responses ranged from 26% to 59% across the 3 MBI-HSS categories, but only about 15% had unfavorable scores in all 3. Mean mental composite score of the SF-12 was 1 standard deviation below normative values and was significantly associated with all MBI-HSS components. With SSPC-14, respondents scored better in work satisfaction and professional support than in personal support and workload. Males scored worse on DP and personal accomplishment and, relative to attending physicians, residents scored worse on DP. There was no significant association between MBI-HSS and substance use. CONCLUSIONS: Many anesthesiologists exhibit some high-risk burnout characteristics, and these are associated with lower mental health scores. Personal and professional support were associated with less emotional exhaustion, but overall burnout scores were associated with work satisfaction and professional support. Respondents were generally economically satisfied but also felt less in control at work and that their job kept them from friends and family. The association between burnout and substance use may not be as strong as previously believed. Additional work, perhaps with other survey instruments, is needed to confirm our results.

Tissue sodium accumulation and peripheral insulin sensitivity in maintenance hemodialysis patients.

BACKGROUND: Recent data suggest that sodium (Na+ ) is stored in the muscle and skin without commensurate water retention in maintenance hemodialysis (MHD) patients. In this study, we hypothesized that excessive Na+ accumulation would be associated with abnormalities in peripheral insulin action. METHODS: Eleven MHD patients and eight controls underwent hyperinsulinemic-euglycemic-euaminoacidemic clamp studies to measure glucose (GDR) and leucine disposal rates (LDR), as well as lower left leg 23 Na magnetic resonance imaging to measure Na+ concentration in the muscle and skin tissue. RESULTS: The median GDR and LDR levels were lower, and the median muscle Na+ concentration was higher in MHD patients compared with controls. No significant difference was found regarding skin Na+ concentration between group comparisons. Linear regression revealed inverse relationships between muscle Na+ concentration and GDR and LDR in MHD patients, whereas no relationship was observed in controls. There was no association between skin Na+ content and GDR or LDR in either MHD patients or controls. CONCLUSIONS: These data suggest that excessive muscle Na+ content might be a determinant of IR in MHD patients, although the causality and mechanisms remain to be proven.

Reduced snow cover alters root-microbe interactions and decreases nitrification rates in a northern hardwood forest.

Snow cover is projected to decline during the next century in many ecosystems that currently experience a seasonal snowpack. Because snow insulates soils from frigid winter air temperatures, soils are expected to become colder and experience more winter soil freeze-thaw cycles as snow cover continues to decline. Tree roots are adversely affected by snowpack reduction, but whether loss of snow will affect root-microbe interactions remains largely unknown. The objective of this study was to distinguish and attribute direct (e.g., winter snow- and/or soil frost-mediated) vs. indirect (e.g., root-mediated) effects of winter climate change on microbial biomass, the potential activity of microbial exoenzymes, and net N mineralization and nitrification rates. Soil cores were incubated in situ in nylon mesh that either allowed roots to grow into the soil core (2 mm pore size) or excluded root ingrowth (50 µm pore size) for up to 29 months along a natural winter climate gradient at Hubbard Brook Experimental Forest, NH (USA). Microbial biomass did not differ among ingrowth or exclusion cores. Across sampling dates, the potential activities of cellobiohydrolase, phenol oxidase, and peroxidase, and net N mineralization rates were more strongly related to soil volumetric water content (P < 0.05; R2  = 0.25-0.46) than to root biomass, snow or soil frost, or winter soil temperature (R2  < 0.10). Root ingrowth was positively related to soil frost (P < 0.01; R2  = 0.28), suggesting that trees compensate for overwinter root mortality caused by soil freezing by re-allocating resources towards root production. At the sites with the deepest snow cover, root ingrowth reduced nitrification rates by 30% (P < 0.01), showing that tree roots exert significant influence over nitrification, which declines with reduced snow cover. If soil freezing intensifies over time, then greater compensatory root growth may reduce nitrification rates directly via plant-microbe N competition and indirectly through a negative feedback on soil moisture, resulting in lower N availability to trees in northern hardwood forests.