Impact of Rank, Provider Specialty, and Unit Sustainment Training Frequency on Military Critical Care Air Transport Team Readiness.

BACKGROUND: The Critical Care Air Transport (CCAT) Advanced Course utilizes fully immersive high-fidelity simulations to assess personnel readiness for deployment. This study aims to determine whether simple well-defined demographic identifiers can be used to predict CCAT students' performance at CCAT Advanced. MATERIALS AND METHODS: CCAT Advanced student survey data and course status (pass/fail) between March 2006 and April 2020 were analyzed. The data included students' Air Force Specialty Code (AFSC), military status (active duty and reserve/guard), CCAT deployment experience (yes/no), prior CCAT Advanced training (yes/no), medical specialty, rank, and unit sustainment training frequency (never, frequency less often than monthly, and frequency at least monthly). Following descriptive analysis and comparative tests, multivariable regression was used to identify the predictors of passing the CCAT Advanced course for each provider type. RESULTS: A total of 2,576 student surveys were analyzed: 694 (27%) physicians (MDs), 1,051 (40%) registered nurses (RNs), and 842 (33%) respiratory therapists (RTs). The overall passing rates were 92.2%, 90.3%, and 85.4% for the MDs, RNs, and RTs, respectively. The students were composed of 579 (22.5%) reserve/guard personnel, 636 (24.7%) with CCAT deployment experience, and 616 (23.9%) with prior CCAT Advanced training. Regression analysis identified groups with lower odds of passing; these included (1) RNs who promoted from Captain to Major (post-hoc analysis, P = .03), (2) RTs with rank Senior Airman, as compared to Master Sergeants (post-hoc analysis, P = .04), and (3) MDs with a nontraditional AFSC (P = .0004). Predictors of passing included MDs and RNs with CCAT deployment experience, odds ratio 2.97 (P = .02) and 2.65 (P = .002), respectively; and RTs who engaged in unit CCAT sustainment at least monthly (P = .02). The identifiers prior CCAT Advanced training or reserve/guard military status did not confer a passing advantage. CONCLUSION: Our main result is that simple readily available metrics available to unit commanders can identify those members at risk for poor performance at CCAT Advanced readiness training; these include RNs with rank Major or above, RTs with rank Senior Airman, and RTs who engage in unit sustainment training less often than monthly. Finally, MD specialties which are nontraditional for CCAT have significantly lower CCAT Advanced passing rates, reserve/guard students did not outperform active duty students, there was no difference in the performance between different RN specialties, and for MD and RN students' previous deployment experience was a strong predictor of passing.

Can the Cans: Determinants of Container Deposit Behavior before and after Introduction of a Container Refund Scheme.

OBJECTIVE: Container deposit schemes are often hailed as a useful avenue to increase consumer recycling rates. Yet, there is little research investigating within-person changes in people's beliefs and behavior following the implementation of these schemes, or tests of the mechanisms by which such change has occurred. METHODS: The current study fills this knowledge gap and assessed container recycling behavior and habits as well as the social cognition factors of attitudes, subjective norms, perceived behavioral control, and intentions in a sample of 90 Queenslanders before the implementation of the container deposit scheme and one and three months post-implementation. RESULTS: Analysis of variance indicated more frequent recycling behavior following the implementation of the scheme, as well as stronger habits, intentions, and perceived behavioral control. CONCLUSIONS: Such a concomitant change in behavior, beliefs, and habits provides support for behavior change theory, while also flagging potential targets for strategies that can be paired with container deposit schemes to enhance their efficacy and uptake.

Validation of reaction norm breeding values for robustness in Australian sheep.

BACKGROUND: There can be variation between animals in how stable their genetic merit is across different environments due to genotype-by-environment (G×E) interactions. This variation could be used in breeding programs to select robust genotypes that combine high overall performance with stable genetic ranking across environments. There have been few attempts to validate breeding values for robustness in livestock, although this is a necessary step towards their implementation in selection decisions. The objective of this study was to validate breeding values for the robustness of body weight across different growth environments that were estimated using reaction norm models in sheep data. RESULTS: Using threefold cross-validation for the progeny of 337 sires, the average correlation between single-step breeding values for the reaction norm slope and the realised robustness of progeny across different growth environments was 0.21. The correlation between breeding values for the reaction slope estimated independently in two different datasets linked by common sires was close to the expected correlation based on theory. CONCLUSIONS: Slope estimated breeding values (EBV) obtained using reaction norm models were predictive of the phenotypic robustness of progeny across different environments and were consistent for sires with progeny in two different datasets. Selection based on reaction norm EBV could be used to increase the robustness of a population to environmental variation.

Combined purebred and crossbred genetic evaluation of Columbia, Suffolk, and crossbred lamb birth and weaning weights: systematic effects and heterogeneous variances.

Despite the benefits of crossbreeding on animal performance, genetic evaluation of sheep in the U.S. does not directly incorporate records from crossbred lambs. Crossbred animals may be raised in different environments as compared to purebreds. Systemic factors such as age of dam and birth and rearing type may, therefore, affect purebred and crossbred performance differently. Furthermore, crossbred performance may benefit from heterozygosity, and genetic and environmental variances may be heterogeneous in different breeds and their crosses. Such issues must be accounted for in a combined (purebred and crossbred) genetic evaluation. The objectives of this study were to i) determine the effect of dam age and birth type on birth weight, and dam age and birth-rearing type on weaning weight, in purebred and crossbred lambs, ii) test for heterogeneous genetic and environmental variances in those weights, and iii) assess the impact of including weights on crossbred progeny on sire estimated breeding values (EBV). Performance records were available on purebred Columbia and Suffolk lambs. Crossbred information was available on lambs sired by Suffolk, Columbia or Texel rams mated to Columbia, Suffolk, or crossbred ewes. A multiple-trait animal model was fitted in which weights from Columbia, Suffolk, or crossbred lambs were considered different traits. At birth, there were 4,160, 2,356, and 5,273 Columbia, Suffolk, and crossbred records, respectively, with means (SD) of 5.14 (1.04), 5.32 (1.14), and 5.43 (1.23) kg, respectively. At weaning, on average at 122 (12) d, there were 2,557, 980, and 3,876 Columbia, Suffolk, and crossbred records, respectively, with corresponding means of 39.8 (7.2), 40.3 (7.9), and 39.6 (8.0) kg. Dam age had a large positive effect on birth and weaning weight in pure and crossbred lambs. At birth, however, the predicted effect was larger in crossbred and Suffolk lambs. While an increase in a number of lambs born and reared had a strong and negative influence on birth and weaning weight, the size of the effect did not differ across-breed types. Environmental variances were similar at birth and weaning, but additive variances differed among breed types for both weights. Combining purebred and crossbred information in the evaluation not only improved predictions of genetic merit in purebred sires but also allowed for direct comparisons of sires of different breeds. Breeders thus can benefit from an additional tool for making selection decisions.

Combining multiple breeds in a genetic evaluation allows for their direct comparison. However, differences in management and other systematic effects among breeds may affect the evaluation. Estimates of genetic merit of sires may also be biased by heterosis in crossbred progeny. We examined genetic and environmental factors that affect the efficacy of a multi-breed genetic evaluation. Birth and weaning weights of Columbia, Suffolk, and their cross, were available. Depending on the breed type, the systematic effects of dam age and either birth or birth-rearing type on weights differed. Separately for birth and weaning, weights were defined as a different trait for each breed type. A multi-breed, multi-trait model was fitted that accounted for systematic effects unique to a breed type, and heterosis. Estimated direct and maternal heritabilities were moderate. Genetic correlations between breeds were moderate to high. Estimates of genetic merit of Columbia and Suffolk sires were unaffected by bias due to heterosis and environmental effects when crossbred lambs were included in a purebred or a combined Columbia, Suffolk, and crossbred evaluation. For direct across-breed comparisons, breed type-specific adjustments for systematic effects are necessary when combining weight data on pure and crossbred lambs in a joint genetic evaluation.

Impingement-related osteolysis in Motec total wrist arthroplasty: an explant analysis and review of the literature.

We present five cases of osteolysis in the Motec total wrist prosthesis, three around the radial implant, one around the metacarpal implant and one around both. Three of these were progressive and required revision, and biomechanical explant analyses of these revised prostheses were performed. Ex vivo testing of the contact points of the Motec implants was also performed at maximum extension. Here, impingement occurs between the metacarpal screw and the dorsal rim of the cup (non-articulating surfaces) with the short-necked prosthesis, leading to metacarpal screw damage, titanium debris formation and osteolysis. An analysis of three previously published cases suggests that this may have been the likely mode of failure in those cases. This complication is preventable by avoiding use of the short-neck prosthesis.Level of evidence: IV.

Learning curves in Motec total wrist arthroplasty: an international cohort study.

We examined the learning curve of Motec total wrist arthroplasty (TWA) of six experienced surgeons in their first 30 cases. Three times more complications/revisions were encountered in the first half of the study compared with the second half. Motec TWA surgery should be concentrated in a smaller number of centres performing higher volumes.

Complication rates and modes of short and medium-term failure in Motec total wrist arthroplasty: an international cohort study.

The aim of this study was to analyse the short- and medium-term complications of the Motec total wrist arthroplasty (TWA). Identifying exact modes of failure and their causes should allow surgeons to avoid or mitigate these risks in the future. Retrospective analysis of prospectively collected data from six hand surgeons at five international centres provided details of 171 Motec TWAs. The mean follow-up was 5.8 years (range 18 months to 12 years). There were 33 (19%) complications within our cohort, with a revision rate of 8.2% (14 revisions). There was no difference in complication rates between metal-on-metal and metal-on-polymer articulations. Failure of osseointegration was the most common complication. Problems with soft tissue balancing, implant impingement related osteolysis, bony impingement and metacarpal fracture were found to be other preventable causes of failure in this series. Elimination of these preventable complications will improve survival rates for this implant.Level of evidence: IV.

Long-term results and explant analysis of the ReMotion total wrist arthroplasty.

The ReMotion wrist replacement has good short- to medium-term survival with an acceptable complication profile as we previously reported in a cohort of patients with rheumatoid arthritis. We now report the long-term results of the same cohort and details of explant analysis of revisions undertaken for aseptic loosening. A total of 16 wrists were reviewed. Seven prostheses remain in situ with no obvious signs of wear or radiological loosening at a mean follow-up of 15.5 years. Three wrists had been revised: one for infection and two for aseptic loosening. Five patients (six wrists) died 2-9 years after operation from unrelated causes. Explant analysis demonstrated relatively minor wear compared with the published results of the Universal-2 prosthesis. We hypothesize that this may be explained by differences in polyethylene sterilization and prosthetic design. The ReMotion wrist replacement has favourable long-term results in patients with rheumatoid arthritis with a 16-year survival rate of 78%-86%.Level of evidence: IV.

Using x-ray micro computed tomography to quantify intracochlear fibrosis after cochlear implantation in a Guinea pig model.

Cochlear implants (CIs) allow individuals with profound hearing loss to understand speech and perceive sounds. However, not all patients obtain the full benefits that CIs can provide and the cause of this disparity is not fully understood. One possible factor for the variability in outcomes after cochlear implantation, is the development of fibrotic scar tissue around the implanted electrode. It has been hypothesised that limiting the extent of fibrosis after implantation may improve overall CI function, and longevity of the device. Currently, histology is often used to quantify the extent of intracochlear tissue growth after implantation however this method is labour intensive, time-consuming, often involves significant user bias, and causes physical distortion of the fibrosis. Therefore, this study aimed to evaluate x-ray micro computed tomography (µCT) as a method to measure the amount and distribution of fibrosis in a guinea pig model of cochlear implantation. Adult guinea pigs were implanted with an inactive electrode, and cochleae harvested eight weeks later (n = 7) and analysed using µCT, to quantify the extent of tissue reaction, followed by histological analysis to confirm that the tissue was indeed fibrotic. Cochleae harvested from an additional six animals following implantation were analysed by µCT, before and after contrast staining with osmium tetroxide (OsO4), to enhance the visualisation of soft tissues within the cochlea, including the tissue reaction. Independent analysis by two observers showed that the quantification method was robust and provided additional information on the distribution of the response within the cochlea. Histological analysis revealed that µCT visualised dense collagenous material and new bone formation but did not capture loose, areolar fibrotic tissue. Treatment with OsO4 significantly enhanced the visible tissue reaction detected using µCT. Overall, µCT is an alternative and reliable method that can be used to quantify the extent of the CI-induced intracochlear tissue response and will be a useful tool for the in vivo assessment of novel anti-fibrotic treatments.

Evidence That Ultrafast Nonquantal Transmission Underlies Synchronized Vestibular Action Potential Generation.

Amniotes evolved a unique postsynaptic terminal in the inner ear vestibular organs called the calyx that receives both quantal and nonquantal (NQ) synaptic inputs from Type I sensory hair cells. The nonquantal synaptic current includes an ultrafast component that has been hypothesized to underlie the exceptionally high synchronization index (vector strength) of vestibular afferent neurons in response to sound and vibration. Here, we present three lines of evidence supporting the hypothesis that nonquantal transmission is responsible for synchronized vestibular action potentials of short latency in the guinea pig utricle of either sex. First, synchronized vestibular nerve responses are unchanged after administration of the AMPA receptor antagonist CNQX, while auditory nerve responses are completely abolished. Second, stimulus evoked vestibular nerve compound action potentials (vCAP) are shown to occur without measurable synaptic delay and three times shorter than the latency of auditory nerve compound action potentials (cCAP), relative to the generation of extracellular receptor potentials. Third, paired-pulse stimuli designed to deplete the readily releasable pool (RRP) of synaptic vesicles in hair cells reveal forward masking in guinea pig auditory cCAPs, but a complete lack of forward masking in vestibular vCAPs. Results support the conclusion that the fast component of nonquantal transmission at calyceal synapses is indefatigable and responsible for ultrafast responses of vestibular organs evoked by transient stimuli.SIGNIFICANCE STATEMENT The mammalian vestibular system drives some of the fastest reflex pathways in the nervous system, ensuring stable gaze and postural control for locomotion on land. To achieve this, terrestrial amniotes evolved a large, unique calyx afferent terminal which completely envelopes one or more presynaptic vestibular hair cells, which transmits mechanosensory signals mediated by quantal and nonquantal (NQ) synaptic transmission. We present several lines of evidence in the guinea pig which reveals the most sensitive vestibular afferents are remarkably fast, much faster than their auditory nerve counterparts. Here, we present neurophysiological and pharmacological evidence that demonstrates this vestibular speed advantage arises from ultrafast NQ electrical synaptic transmission from Type I hair cells to their calyx partners.

The Ability of Military Critical Care Air Transport Members to Visually Estimate Percent Systolic Pressure Variation.

INTRODUCTION: Inappropriate fluid management during patient transport may lead to casualty morbidity. Percent systolic pressure variation (%SPV) is one of several technologies that perform a dynamic assessment of fluid responsiveness (FT-DYN). Trained anesthesia providers can visually estimate and use %SPV to limit the incidence of erroneous volume management decisions to 1-4%. However, the accuracy of visually estimated %SPV by other specialties is unknown. The aim of this article is to determine the accuracy of estimated %SPV and the incidence of erroneous volume management decisions for Critical Care Air Transport (CCAT) team members before and after training to visually estimate and utilize %SPV. MATERIAL AND METHODS: In one sitting, CCAT team providers received didactics defining %SPV and indicators of fluid responsiveness and treatment with %SPV ≤7 and ≥14.5 defining a fluid nonresponsive and responsive patient, respectively; they were then shown ten 45-second training arterial waveforms on a simulated Propaq M portable monitor's screen. Study subjects were asked to visually estimate %SPV for each arterial waveform and queried whether they would treat with a fluid bolus. After each training simulation, they were told the true %SPV. Seven days post-training, the subjects were shown a different set of ten 45-second testing simulations and asked to estimate %SPV and choose to treat, or not. Nonparametric limits of agreement for differences between true and estimated %SPV were analyzed using Bland-Altman graphs. In addition, three errors were defined: (1) %SPV visual estimate errors that would label a volume responsive patient as nonresponsive, or vice versa; (2) incorrect treatment decisions based on estimated %SPV (algorithm application errors); and (3) incorrect treatment decisions based on true %SPV (clinically significant treatment errors). For the training and testing simulations, these error rates were compared between, and within, provider groups. RESULTS: Sixty-one physicians (MDs), 64 registered nurses (RNs), and 53 respiratory technicians (RTs) participated in the study. For testing simulations, the incidence and 95% CI for %SPV estimate errors with sufficient magnitude to result in a treatment error were 1.4% (0.5%, 3.2%), 1.6% (0.6%, 3.4%), and 4.1% (2.2%, 6.9%) for MDs, RNs, and RTs, respectively. However, clinically significant treatment errors were statistically more common for all provider types, occurring at a rate of 7%, 10%, and 23% (all P < .05). Finally, students did not show clinically relevant reductions in their errors between training and testing simulations. CONCLUSIONS: Although most practitioners correctly visually estimated %SPV and all students completed the training in interpreting and applying %SPV, all groups persisted in making clinically significant treatment errors with moderate to high frequency. This suggests that the treatment errors were more often driven by misapplying FT-DYN algorithms rather than by inaccurate visual estimation of %SPV. Furthermore, these errors were not responsive to training, suggesting that a decision-making cognitive aid may improve CCAT teams' ability to apply FT-DYN technologies.

Using macular velocity measurements to relate parameters of bone conduction to vestibular compound action potential responses.

To examine mechanisms responsible for vestibular afferent sensitivity to transient bone conducted vibration, we performed simultaneous measurements of stimulus-evoked vestibular compound action potentials (vCAPs), utricular macula velocity, and vestibular microphonics (VMs) in anaesthetized guinea pigs. Results provide new insights into the kinematic variables of transient motion responsible for triggering mammalian vCAPs, revealing synchronized vestibular afferent responses are not universally sensitive to linear jerk as previously thought. For short duration stimuli (< 1 ms), the vCAP increases magnitude in close proportion to macular velocity and temporal bone (linear) acceleration, rather than other kinematic elements. For longer duration stimuli, the vCAP magnitude switches from temporal bone acceleration sensitive to linear jerk sensitive while maintaining macular velocity sensitivity. Frequency tuning curves evoked by tone-burst stimuli show vCAPs increase in proportion to onset macular velocity, while VMs increase in proportion to macular displacement across the entire frequency bandwidth tested between 0.1 and 2 kHz. The subset of vestibular afferent neurons responsible for synchronized firing and vCAPs have been shown previously to make calyceal synaptic contacts with type I hair cells in the striolar region of the epithelium and have irregularly spaced inter-spike intervals at rest. Present results provide new insight into mechanical and neural mechanisms underlying synchronized action potentials in these sensitive afferents, with clinical relevance for understanding the activation and tuning of neurons responsible for driving rapid compensatory reflex responses.

A mathematical model for mechanical activation and compound action potential generation by the utricle in response to sound and vibration.

Introduction: Calyx bearing vestibular afferent neurons innervating type I hair cells in the striolar region of the utricle are exquisitely sensitive to auditory-frequency air conducted sound (ACS) and bone conducted vibration (BCV). Here, we present experimental data and a mathematical model of utricular mechanics and vestibular compound action potential generation (vCAP) in response to clinically relevant levels of ACS and BCV. Vibration of the otoconial layer relative to the sensory epithelium was simulated using a Newtonian two-degree-of-freedom spring-mass-damper system, action potential timing was simulated using an empirical model, and vCAPs were simulated by convolving responses of the population of sensitive neurons with an empirical extracellular voltage kernel. The model was validated by comparison to macular vibration and vCAPs recorded in the guinea pig, in vivo. Results: Transient stimuli evoked short-latency vCAPs that scaled in magnitude and timing with hair bundle mechanical shear rate for both ACS and BCV. For pulse BCV stimuli with durations <0.8 ms, the vCAP magnitude increased in proportion to temporal bone acceleration, but for pulse durations >0.9 ms the magnitude increased in proportion to temporal bone jerk. Once validated using ACS and BCV data, the model was applied to predict blast-induced hair bundle shear, with results predicting acute mechanical damage to bundles immediately upon exposure. Discussion: Results demonstrate the switch from linear acceleration to linear jerk as the adequate stimulus arises entirely from mechanical factors controlling the dynamics of sensory hair bundle deflection. The model describes the switch in terms of the mechanical natural frequencies of vibration, which vary between species based on morphology and mechanical factors.

Experiences of adults living with a kidney transplant-Effects on physical activity, physical function, and quality of life: A descriptive phenomenological study.

BACKGROUND: Although kidney transplantation is the best treatment for kidney failure, scarce research has examined its effects on physical activity, physical function and quality of life. OBJECTIVES: To investigate the experiences of a group of adults living with advanced kidney disease focusing on quality of life, physical activity and function and to see how findings differ in a group of kidney transplant recipients. APPROACH: Individual semi-structured interviews were conducted with adults with advanced kidney disease (n = 10; 70.5 ± 8.9 years) and adults who had received a kidney transplant (n = 10; 50.7 ± 11.5 years; transplant age: 42.7 ± 20.9 months). Interviews were transcribed verbatim, thematically analysed and composite vignettes developed. FINDINGS: Individuals with advanced kidney disease described a sense of loss and alteration to their life plans. Kidney transplant recipients reported increased freedom, independence and a return to near normality, with improved quality of life, physical activity and function compared with their pre-transplant lives. However, transplant recipients also described living with anxiety about the health of their transplant and fear it may fail. CONCLUSION: Whilst adults living with advanced kidney disease often experience a reduced quality of life, physical activity and function, kidney transplantation can help facilitate a return to pre-disease levels of physical activity, physical function and quality of life. However, transplant recipients also reported living with anxiety around their new kidney failing. This study demonstrates the variability in the lived experiences of adults living with advanced kidney disease or a kidney transplant and highlights the need for patient-centred care.

Exploring patients' experiences of the impact of dialysis therapies on quality of life and wellbeing.

BACKGROUND: When people with chronic kidney disease reach kidney failure, renal replacement therapy is usually required to improve symptoms and maintain life. Although in-centre haemodialysis is most commonly used for this purpose, other forms of dialysis are available, including home haemodialysis and peritoneal dialysis. OBJECTIVES: We aimed to explore the experiences of adults living with chronic kidney disease who were either approaching the need for dialysis or had reached kidney failure and were receiving a form of dialysis. In particular, we explored how different forms of dialysis affect their quality of life, wellbeing, and physical activity. METHODS: Individual semistructured interviews were conducted with 40 adults with kidney failure, comprising four groups (n = 10 each): those receiving in-centre haemodialysis, home haemodialysis or peritoneal dialysis, or predialysis. Interviews were transcribed verbatim, thematically analysed, and then composite vignettes were subsequently developed to present a rich narrative of the collective experiences of each group. FINDINGS: Compared with adults who were predialysis, quality of life and wellbeing improved upon initiation of their home haemodialysis or peritoneal dialysis. Conversely, minimal improvement was perceived by those receiving in-centre haemodialysis. Low physical activity was reported across all four groups, although those receiving home haemodialysis and peritoneal dialysis reported a greater desire and ability to be physically active than those in-centre. CONCLUSION: These findings highlight that dialysis modalities not requiring regular hospital attendance (i.e., home haemodialysis and peritoneal dialysis) improve independence, quality of life, wellbeing, and can facilitate a more physically active lifestyle.

Descriptive Analysis of Intratheater Critical Care Air Transport Team Patient Movements During Troop Drawdown: Afghanistan (2017-2019).

BACKGROUND: The majority of critical care air transport (CCAT) flights are regulated, meaning that a theater-validating flight surgeon has confirmed that the patient is medically cleared for flight and that evacuation is appropriate. If the conditions on the ground do not allow for this process, the flight is unregulated. Published data are limited regarding CCAT unregulated missions to include the period of troop drawdown at the end of the Afghanistan conflict. The objective of our study was to characterize the unregulated missions within Afghanistan during troop drawdown and compare them to regulated missions during the same timeframe. STUDY DESIGN: We performed a retrospective review of all CCAT medical records of patients transported via CCAT within Afghanistan between January 2017 and December 2019. We abstracted data from the records, including mission characteristics, patient demographics, injury descriptors, preflight military treatment facility procedures, CCAT procedures, in-flight CCAT treatments, in-flight events, and equipment issues. Following descriptive and comparative analysis, a Cochran-Armitage test was performed to evaluate the statistical significance of the trend in categorical data over time. Multivariable regression was used to assess the association between vasopressors and preflight massive transfusions, preflight surgical procedures, injury patterns, and age. RESULTS: We reviewed 147 records of patients transported via CCAT: 68 patients were transported in a regulated fashion and 79 on an unregulated flight. The number of patients evacuated increased year-over-year (n = 22 in 2017, n = 57 in 2018, and n = 68 in 2019, P < .001), and the percentage of missions that were unregulated grew geometrically (14%, n = 3 in 2017; 37%, n = 21 in 2018; and 81%, n = 55 in 2019, P < .001). During the time studied, CCAT teams were being used more to decompress forward surgical teams (FST) and, therefore, they were transporting patients just hours following initial damage control surgery in an unregulated fashion. In 2 instances, CCAT decompressed an FST following a mass casualty, during which aeromedical evacuation (AE) crews assisted with patient care. For the regulated missions, the treatments that were statistically more common were intravenous fluids, propofol, norepinephrine, any vasopressors, and bicarbonate. During unregulated missions, the statistically more common treatments were ketamine, fentanyl, and 3% saline. Additional analysis of the mechanically ventilated patient subgroup revealed that vasopressors were used twice as often on regulated (38%) vs. unregulated (13%) flights. Multivariable regression analysis demonstrated that traumatic brain injury (TBI) was the only significant predictor of in-flight vasopressor use (odds ratio = 3.53, confidence interval [1.22, 10.22], P = .02). CONCLUSION: During the troop drawdown in Afghanistan, the number of unregulated missions increased geometrically because the medical footprint was decreasing. During unregulated missions, CCAT providers used ketamine more frequently, consistent with Tactical Combat Casualty Care guidelines. In addition, TBI was the only predictor of vasopressor use and may reflect an attempt to adhere to unmonitored TBI clinical guidelines. Interoperability between CCAT and AE teams is critical to meet mass casualty needs in unregulated mission environments and highlights a need for joint training. It remains imperative to evaluate changes in mission requirements to inform en route combat casualty care training.

Model definition for genetic evaluation of purebred and crossbred lambs including heterosis.

Crossbreeding is a common practice among commercial sheep producers to improve animal performance. However, genetic evaluation of U.S. sheep is performed within breed type (terminal sire, semi-prolific, and western range). While incorporating crossbred records may improve assessment of purebreds, it requires accounting for heterotic and breed effects in the evaluation. The objectives of this study were to: 1) describe the development of a paternal composite (PC) line, 2) determine the effect of direct and maternal heterosis on growth traits of crossbred lambs, 3) estimate (co)variance components for direct and maternal additive, and uncorrelated maternal environmental, effects, and 4) provide an interpretation of the estimates of random effects of genetic groups, and to use those solutions to compare the genetic merit of founding breed subpopulations. Data included purebred and crossbred records on birth weight (BN; n = 14,536), pre-weaning weight measured at 39 or 84 d (WN; n = 9,362) depending on year, weaning weight measured at 123 d (WW; n = 9,297), and post-weaning weight measured at 252 d (PW; n = 1,614). Mean (SD) body weights were 5.3 (1.1), 16.8 (3.9) and 28.0 (7.6), 39.1 (7.2), and 54.2 (8.7) kg for BN, WN (at the two ages), WW, and PW, respectively. In designed experiments, the Siremax, Suffolk, Texel, Polypay, Columbia, Rambouillet, and Targhee breeds were compared within the same environment. Estimates of heterotic effects and covariance components were obtained using a multiple trait animal model. Genetic effects based on founders' breeds were significant and included in the model. Percent estimates of direct heterosis were 2.89 ± 0.61, 2.60 ± 0.65, 4.24 ± 0.56, and 6.09 ± 0.86, and estimates of maternal heterosis were 1.92 ± 0.87, 4.64 ± 0.80, 3.95 ± 0.66, and 4.04 ± 0.91, for BN, WN, WW, and PW, respectively. Correspondingly, direct heritability estimates were 0.17 ± 0.02, 0.13 ± 0.02, 0.17 ± 0.02, and 0.46 ± 0.04 for BN, WN, WW, and PW. Additive maternal effects accounted for trivial variation in PW. For BN, WN, and WW, respectively, maternal heritability estimates were 0.16 ± 0.02, 0.10 ± 0.02, and 0.07 ± 0.01. Uncorrelated maternal environmental effects accounted for little variation in any trait. Direct and maternal heterosis had considerable impact on growth traits, emphasizing the value of crossbreeding and the need to account for heterosis, in addition to breed effects, if crossbred lamb information is included in genetic evaluation.

Crossbreeding is common in commercial sheep enterprises. It allows breeds with different attributes to be combined to generate crossbred progeny tailored to production environments and customer preferences. Additionally, crossbreds often benefit from heterosis, performing at levels above the average of their parental breeds. Over two decades, body weights were collected at birth and at pre-weaning, weaning, and post-weaning ages on purebred and crossbred lambs from semi-prolific (Polypay), western range (Columbia, Rambouillet, Targhee), and terminal sire (Siremax, Suffolk, Texel) breeds at the U.S. Sheep Experiment Station. When combined, the value of direct heterosis­that due to a lamb being crossbred­and maternal heterosis­that due to the lamb's dam being crossbred­increased birth (5%) and post-natal (up to 10%) weights in crossbred lambs. This highlights the value of crossbreeding to the U.S. sheep industry, especially in western range production systems. Genetic variation between and within breeds also was detected for the purebred parental breeds. Such heterotic and breed effects must be accounted for if crossbred performance is to be incorporated in genetic evaluation of purebreds. Therefore, these results provide the foundation for utilizing crossbred information in the evaluation and selection of purebred sheep in the United States.

Relevance of Deployment Experience and Clinical Practice Characteristics on Military Critical Care Air Transport Team Readiness: A Study of Simulation Construct Validity.

INTRODUCTION: The Critical Care Air Transport Team (CCATT) Advanced course utilizes fully immersive high-fidelity simulations to train CCATT personnel and assess their readiness for deployment. This study aims to (1) determine whether these simulations correctly discriminate between students with previous deployment experience ("experienced") and no deployment experience ("novices") and (2) examine the effects of students' clinical practice environment on their performance during training simulations. MATERIALS AND METHODS: Critical Care Air Transport Team Advanced student survey data and course status (pass/no pass) between March 2006 and April 2020 were analyzed. The data included students' specialty, previous exposure to the CCATT Advanced course, previous CCATT deployment experience, years in clinical practice (<5, 5-15, and >15 years), and daily practice of critical care (yes/no), as well as a description of the students' hospital to include the total number of hospital (<100, 100-200, 201-400, and >400) and intensive care unit (0, 1-10, 11-20, and >20) beds. Following descriptive analysis and comparative tests, multivariable regression was used to identify the predictors of passing the CCATT Advanced course. RESULTS: A total of 2,723 surveys were analyzed: 841 (31%) were physicians (MDs), 1,035 (38%) were registered nurses, and 847 (31%) were respiratory therapists (RTs); 641 (24%) of the students were repeating the course for sustainment training and 664 (24%) had previous deployment experience. Grouped by student specialty, the MDs', registered nurses', and RTs' pass rates were 92.7%, 90.6%, and 85.6%, respectively. Multivariable regression results demonstrated that deployment experience was a robust predictor of passing. In addition, the >15 years in practice group had a 47% decrease in the odds of passing as compared to the 5 to 15 years in practice group. Finally, using MDs as the reference, the RTs had a 61% decrease in their odds of passing. The daily practice of critical care provided a borderline but nonsignificant passing advantage, whereas previous CCATT course exposure had no effect. CONCLUSION: Our primary result was that the CCATT Advanced simulations that are used to evaluate whether the students are mission ready successfully differentiated "novice" from "experienced" students; this is consistent with valid simulation constructs. Finally, novice CCATT students do not sustain their readiness skills during the period between mandated refresher training.