When Antimicrobial Treatment and Surgical Prophylaxis Collide: A Stewardship Opportunity.

Background: In 2002, the Centers for Medicare and Medicaid Services (CMS) in collaboration with the Centers for Disease Control and Prevention (CDC) established the Surgical Infection Prevention (SIP) project for the purposes of developing and standardizing quality improvement measures known to reduce the rates of post-operative surgical site infections (SSIs). Four years later the Surgical Care Improvement Project (SCIP), an expansion of SIP, was published in governmental Specifications Manual for National Inpatient Quality Measures and provided several additional initiatives applicable to the perioperative period. Central to both projects are the assurance of the timeliness, selection, and duration of peri-operative surgical prophylactic antibiotics. In support of this objective, various medical associations, such as the American Society of Health-System Pharmacists (ASHP) and the Infectious Diseases Society of America (IDSA), have developed the Clinical Practice Guidelines for Antimicrobial Prophylaxis in Surgery. To ensure compliance with quality measures, hospitals are required to report data to the Physicians Quality Reporting System, which is then reviewed by CMS for reimbursement purposes and to measure hospital performance. To maintain optimal standards of care and satisfy all core measures, it is expected that patients undergoing most categories of surgical procedures receive prophylactic antibiotics. We recognized that patients already being administered antimicrobial therapy as treatment for the condition requiring the surgery not uncommonly also were prescribed unwarranted and redundant pre-operative antibiotics. Our study was meant to quantify such antibiotic redundancy, which only risks the development of antimicrobial resistance and adverse events, to bolster our and other hospitals antimicrobial stewardship programs. Methods: A retrospective analysis of computerized hospital records over a one-month period of time (November 2022) was conducted focusing on hospital admissions that involved surgical operative procedures. Only those patients who had received a pre-operative surgical prophylactic antibiotic were included in the analysis. Results: Of the 92 surgeries that fulfilled the inclusion criteria, 38 (41.3%) were performed on patients who were already receiving therapeutic antibiotics for more than 24 hours targeted to treat the infection for which they were undergoing surgery. These included laparoscopic cholecystectomy (24), appendectomy (12), wound debridement (12), and soft tissue incision and drainage procedures (9), comprising nearly 50% of each type of these operations performed during the study time period. Conclusion: These findings demonstrate a clear opportunity to strengthen both our, and presumably other, hospitals antimicrobial stewardship programs. Together with physician education, granting the pharmacy the ability to cancel unnecessary and redundant surgical prophylactic antibiotics would conceivably be of great benefit.

Investigating the Relationship between Bleeding, Clotting, and Coagulopathy During Automated Partial REBOA Strategies in a Highly Lethal Porcine Hemorrhage Model.

BACKGROUND: Death due to hemorrhagic shock, particularly, non-compressible truncal hemorrhage (NCTH), remains one of the leading causes of potentially preventable deaths. Automated partial and intermittent resuscitative endovascular balloon occlusion of the aorta (i.e., pREBOA and iREBOA, respectively) are lifesaving endovascular strategies aimed to achieve quick hemostatic control while mitigating distal ischemia. In iREBOA, the balloon is titrated from full occlusion to no occlusion intermittently whereas in pREBOA, a partial occlusion is maintained. Therefore, these two interventions impose different hemodynamic conditions, which may impact coagulation and the endothelial glycocalyx layer (EGL). In this study, we aimed to characterize the clotting kinetics and coagulopathy associated with iREBOA and pREBOA, using thromboelastography (TEG). We hypothesized that iREBOA would be associated with a more hypercoagulopathic response compared to pREBOA due to more oscillatory flow. METHODS: Yorkshire swine (n = 8/group) were subjected to an uncontrolled hemorrhage by liver transection, followed by 90 minutes of automated partial REBOA (pREBOA), intermittent REBOA (iREBOA), or no balloon support (Control). Hemodynamic parameters were continuously recorded, and blood samples were serially collected during the experiment (i.e., 8 key time points: baseline (BL), T0, T10, T30, T60, T90, T120, T210 minutes). Citrated kaolin heparinase (CKH) assays were run on a TEG 5000 (Haemonetics, Niles, IL). General linear mixed models were employed to compare differences in TEG parameters between groups and over time using STATA (v17; College Station, TX), while adjusting for sex and weight. RESULTS: As expected, iREBOA was associated with more oscillations in proximal pressure (and greater magnitudes of peak pressure) because of the intermittent periods of full aortic occlusion and complete balloon deflation, compared to pREBOA. Despite these differences in acute hemodynamics, there were no significant differences in any of the TEG parameters between iREBOA and pREBOA groups. However, animals in both groups experienced a significant reduction in clotting times (R-time: p < 0.001; K-time: p < 0.001) and clot strength (MA: p = 0.01; G: p = 0.02) over the duration of the experiment. CONCLUSIONS: Despite observing acute differences in peak proximal pressures between iREBOA and pREBOA groups, we did not observe any significant differences in TEG parameters between iREBOA and pREBOA. The changes in TEG profiles were significant over time, indicating that a severe hemorrhage followed by both pREBOA and iREBOA can result in faster clotting reaction times (i.e., R-times). Nevertheless, when considering the significant reduction in transfusion requirements and more stable hemodynamic response in the pREBOA group, there may be some evidence favoring pREBOA usage over iREBOA.

Extraction of Proteins from Marine Microbial Communities Sampled by Lab Filters.

A method for the recovery of whole-cell protein extracts from biomass on membrane filters is provided here. The protein extraction method is ideal for biomass captured by filtration of large water volumes, including seawater from marine environments. The protein extraction method includes both chemical disruption and physical disruption to lyse cells and release protein for subsequent metaproteomic analysis.

Impact of regional differences and neighborhood socioeconomic deprivation on the outcomes of patients with lower extremity wounds evaluated by a limb-preservation service.

OBJECTIVE: Management of lower extremity (LE) wounds has evolved with the establishment of specialized limb preservation services. Although clinical factors contribute to limb outcomes, socioeconomic status and community factors also influence the risk for limb loss. The Distressed Community Index (DCI) score is a validated index of social deprivation created to provide an objective measure of economic well-being in United States communities. Few studies have examined the influence of geographic deprivation on outcomes in patients with LE wounds. We examined relationships between socioeconomic deprivation and outcomes of inpatients evaluated by a dedicated limb preservation service (Functional Limb Extremity Service [FLEX]). METHODS: Inpatients referred to FLEX over a 5-year period were included. Wound, Ischemia, foot Infection (WIfI) staging was collected. DCI scores were determined using seven indices based on ZIP Code. Outcomes included any minor or major amputations, any endovascular or open LE revascularization, or wound care procedures. Disease etiology, demographic, and anthropometric data were collected. Associations between neighborhood deprivation and limb-specific outcomes were evaluated in models for the DCI and each of its components separately. RESULTS: A total of 677 patients were included. Thirty-eight percent were female, with a mean age of 64 years. Sixty percent had WIfI stage 3 or 4 risk of amputation, and 43% had WIfI stage 3 or 4 risk of revascularization. Mean ankle-brachial index and toe pressure were 0.96 (standard deviation [SD], 0.43) and 80 (SD, 57) mmHg. Thirty-five percent were non-White. Amputation was performed in 31% of patients, whereas 17% underwent revascularization. The mean distress score was 64 (SD, 24). Mean DCI scores did not differ across WIfI scores. Likewise, overall DCI distress score was not related to any of the outcomes in univariable or multivariable linear regression models. In univariable linear regression models for amputation, higher poverty rate (odds ratio for SD increase 1.20; 95% confidence interval, 1.02-1.42; P = .025) was significantly associated with the outcome. In multivariable models, neither DCI distress score nor any of its components remained significantly associated with the outcome. CONCLUSIONS: Despite known racial disparities in limb-specific outcomes, an aggregate measure of community level distress was not found to be related to outcomes. Although the poverty rate demonstrated a significant relationship with amputation in univariable analysis, this association was not found in multivariable models. Notably, non-White race emerged as a predictor of amputation, underscoring the importance of addressing racial disparities in LE outcomes. Further investigation of potential determinants of LE outcomes is needed, particularly the interaction of such factors with race.

Investigating the Effects of Ultraendurance Running on Athletes' Heart Rate and Blood Pressure.

Background While the effects of exercise on the cardiovascular system are well documented, ultra-endurance sports involve distances beyond the scope of traditional marathons and have grown in popularity at a staggering pace in recent years. While short-term high-intensity exercise stimulates sympathetic rises in heart rate (HR) and blood pressure (BP), the depletion of fluid and electrolyte reserves characteristic of ultra-endurance sports may contribute to decreases in overall BP after the race. If decompensation of the autonomic safety net occurs, orthostatic hypotension as a result of fluid loss during an event may cause fatigue, dizziness, syncope, or collapse. Methodology Subjects were recruited by emails sent to race participants and at pre-race meetings, and no participants were excluded from the study. We observed BP and HR changes in subjects before and after ultramarathon activity in both supine and standing positions over multiple races of variant length and terrain from 50 to 240 km from 2013 to 2018. Participants entered races in Florida, with a mean age of 43.8 and an average body mass index (BMI) of 21.2. In addition to pre-race and post-race measurements, positional post-race BPs and HRs were analyzed for orthostatic trends. Results Of those who participated, 140 completed the events and post-race HR and BP measurements were recorded. The mean systolic blood pressure (SBP) increase from pre-race to post-race standing was 21 mmHg, while the mean diastolic blood pressure (DBP) rise was 13 mmHg. While in a supine position, there was a 15 mmHg increase in SBP from pre-race to post-race, along with a 7 mmHg rise in diastolic pressure. Post-race supine to standing average BP change was insignificant. In the supine position, the mean HR increased by 20 beats per minute (bpm) after the race and by 27 bpm while standing. After the race, the average increase in HR supine to standing was 15 bpm. Conclusions The SBP changed much more notably than diastolic pressures likely due to the increase in stroke volume associated with the sympathetic response during exercise. HR values also climbed as a result of exercise stress in the setting of catecholamine release, and the combined influence contributed to increased cardiac output despite water and electrolyte loss during the event. Post-race, no trends of orthostatic hypotension were noted either with HR or BP when rising from a supine position. The significance of the contribution of fluid intake during the race to compensatory mechanisms under neural control requires further study.

MAN VERSUS MACHINE: PROVIDER DIRECTED VERSUS PRECISION AUTOMATED CRITICAL CARE MANAGEMENT IN A PORCINE MODEL OF DISTRIBUTIVE SHOCK.

ABSTRACT: Background: Critical care management of shock is a labor-intensive process. Precision Automated Critical Care Management (PACC-MAN) is an automated closed-loop system incorporating physiologic and hemodynamic inputs to deliver interventions while avoiding excessive fluid or vasopressor administration. To understand PACC-MAN efficacy, we compared PACC-MAN to provider-directed management (PDM). We hypothesized that PACC-MAN would achieve equivalent resuscitation outcomes to PDM while maintaining normotension with lower fluid and vasopressor requirements. Methods : Twelve swine underwent 30% controlled hemorrhage over 30 min, followed by 45 min of aortic occlusion to generate a vasoplegic shock state, transfusion to euvolemia, and randomization to PACC-MAN or PDM for 4.25 h. Primary outcomes were total crystalloid volume, vasopressor administration, total time spent at hypotension (mean arterial blood pressure <60 mm Hg), and total number of interventions. Results : Weight-based fluid volumes were similar between PACC-MAN and PDM; median and IQR are reported (73.1 mL/kg [59.0-78.7] vs. 87.1 mL/kg [79.4-91.8], P = 0.07). There was no statistical difference in cumulative norepinephrine (PACC-MAN: 33.4 µg/kg [27.1-44.6] vs. PDM: 7.5 [3.3-24.2] µg/kg, P = 0.09). The median percentage of time spent at hypotension was equivalent (PACC-MAN: 6.2% [3.6-7.4] and PDM: 3.1% [1.3-6.6], P = 0.23). Urine outputs were similar between PACC-MAN and PDM (14.0 mL/kg vs. 21.5 mL/kg, P = 0.13). Conclusion : Automated resuscitation achieves equivalent resuscitation outcomes to direct human intervention in this shock model. This study provides the first translational experience with the PACC-MAN system versus PDM.

Whole-body fasciculation detection in amyotrophic lateral sclerosis using motor unit MRI.

OBJECTIVE: Compare fasciculation rates between amyotrophic lateral sclerosis (ALS) patients and healthy controls in body regions relevant for diagnosing ALS using motor unit MRI (MUMRI) at baseline and 6 months follow-up, and relate this to single-channel surface EMG (SEMG). METHODS: Tongue, biceps brachii, paraspinals and lower legs were assessed with MUMRI and biceps brachii and soleus with SEMG in 10 healthy controls and 10 patients (9 typical ALS, 1 primary lateral sclerosis [PLS]). RESULTS: MUMRI-detected fasciculation rates in typical ALS patients were higher compared to healthy controls for biceps brachii (2.40 ± 1.90 cm-3min-1vs. 0.04 ± 0.10 cm-3min-1, p = 0.004), paraspinals (1.14 ± 1.61 cm-3min-1vs. 0.02 ± 0.02 cm-3min-1, p = 0.016) and lower legs (1.42 ± 1.27 cm-3min-1vs. 0.13 ± 0.10 cm-3min-1, p = 0.004), but not tongue (1.41 ± 1.94 cm-3min-1vs. 0.18 ± 0.18 cm-3min-1, p = 0.556). The PLS patient showed no fasciculation. At baseline, 6/9 ALS patients had increased fasciculation rates compared to healthy controls in at least 2 body regions. At follow-up every patient had increased fasciculation rates in at least 2 body regions. The MUMRI-detected fasciculation rate correlated with SEMG-detected fasciculation rates (τ = 0.475, p = 0.006). CONCLUSION: MUMRI can non-invasively image fasciculation in multiple body regions and appears sensitive to disease progression in individual patients. SIGNIFICANCE: MUMRI has potential as diagnostic tool for ALS.

Novel endolithic bacteria of phylum Chloroflexota reveal a myriad of potential survival strategies in the Antarctic desert.

The ice-free McMurdo Dry Valleys of Antarctica are dominated by nutrient-poor mineral soil and rocky outcrops. The principal habitat for microorganisms is within rocks (endolithic). In this environment, microorganisms are provided with protection against sub-zero temperatures, rapid thermal fluctuations, extreme dryness, and ultraviolet and solar radiation. Endolithic communities include lichen, algae, fungi, and a diverse array of bacteria. Chloroflexota is among the most abundant bacterial phyla present in these communities. Among the Chloroflexota are four novel classes of bacteria, here named Candidatus Spiritibacteria class. nov. (=UBA5177), Candidatus Martimicrobia class. nov. (=UBA4733), Candidatus Tarhunnaeia class. nov. (=UBA6077), and Candidatus Uliximicrobia class. nov. (=UBA2235). We retrieved 17 high-quality metagenome-assembled genomes (MAGs) that represent these four classes. Based on genome predictions, all these bacteria are inferred to be aerobic heterotrophs that encode enzymes for the catabolism of diverse sugars. These and other organic substrates are likely derived from lichen, algae, and fungi, as metabolites (including photosynthate), cell wall components, and extracellular matrix components. The majority of MAGs encode the capacity for trace gas oxidation using high-affinity uptake hydrogenases, which could provide energy and metabolic water required for survival and persistence. Furthermore, some MAGs encode the capacity to couple the energy generated from H2 and CO oxidation to support carbon fixation (atmospheric chemosynthesis). All encode mechanisms for the detoxification and efflux of heavy metals. Certain MAGs encode features that indicate possible interactions with other organisms, such as Tc-type toxin complexes, hemolysins, and macroglobulins.IMPORTANCEThe ice-free McMurdo Dry Valleys of Antarctica are the coldest and most hyperarid desert on Earth. It is, therefore, the closest analog to the surface of the planet Mars. Bacteria and other microorganisms survive by inhabiting airspaces within rocks (endolithic). We identify four novel classes of phylum Chloroflexota, and, based on interrogation of 17 metagenome-assembled genomes, we predict specific metabolic and physiological adaptations that facilitate the survival of these bacteria in this harsh environment-including oxidation of trace gases and the utilization of nutrients (including sugars) derived from lichen, algae, and fungi. We propose that such adaptations allow these endolithic bacteria to eke out an existence in this cold and extremely dry habitat.

Improving the precision of shock resuscitation by predicting fluid responsiveness with machine learning and arterial blood pressure waveform data.

Fluid bolus therapy (FBT) is fundamental to the management of circulatory shock in critical care but balancing the benefits and toxicities of FBT has proven challenging in individual patients. Improved predictors of the hemodynamic response to a fluid bolus, commonly referred to as a fluid challenge, are needed to limit non-beneficial fluid administration and to enable automated clinical decision support and patient-specific precision critical care management. In this study we retrospectively analyzed data from 394 fluid boluses from 58 pigs subjected to either hemorrhagic or distributive shock. All animals had continuous blood pressure and cardiac output monitored throughout the study. Using this data, we developed a machine learning (ML) model to predict the hemodynamic response to a fluid challenge using only arterial blood pressure waveform data as the input. A Random Forest binary classifier referred to as the ML fluid responsiveness algorithm (MLFRA) was trained to detect fluid responsiveness (FR), defined as a ≥ 15% change in cardiac stroke volume after a fluid challenge. We then compared its performance to pulse pressure variation, a commonly used metric of FR. Model performance was assessed using the area under the receiver operating characteristic curve (AUROC), confusion matrix metrics, and calibration curves plotting predicted probabilities against observed outcomes. Across multiple train/test splits and feature selection methods designed to assess performance in the setting of small sample size conditions typical of large animal experiments, the MLFRA achieved an average AUROC, recall (sensitivity), specificity, and precision of 0.82, 0.86, 0.62. and 0.76, respectively. In the same datasets, pulse pressure variation had an AUROC, recall, specificity, and precision of 0.73, 0.91, 0.49, and 0.71, respectively. The MLFRA was generally well-calibrated across its range of predicted probabilities and appeared to perform equally well across physiologic conditions. These results suggest that ML, using only inputs from arterial blood pressure monitoring, may substantially improve the accuracy of predicting FR compared to the use of pulse pressure variation. If generalizable, these methods may enable more effective, automated precision management of critically ill patients with circulatory shock.

Metagenomics untangles potential adaptations of Antarctic endolithic bacteria at the fringe of habitability.

Survival and growth strategies of Antarctic endolithic microbes residing in Earth's driest and coldest desert remain virtually unknown. From 109 endolithic microbiomes, 4539 metagenome-assembled genomes were generated, 49.3 % of which were novel candidate bacterial species. We present evidence that trace gas oxidation and atmospheric chemosynthesis may be the prevalent strategies supporting metabolic activity and persistence of these ecosystems at the fringe of life and the limits of habitability.

Dynamic Aortic Pressure Augmentation as a Novel Method of Swine Terminal Blood Extraction.

INTRODUCTION: Uncontrolled hemorrhage models require sufficient quantities of donor blood products to support resuscitation. To that end, we describe a novel method of whole blood extraction from donor swine using resuscitative endovascular balloon occlusion of the aorta (REBOA) to support hemodynamics during terminal blood extraction and its impact on the quality of banked blood. METHODS: Ten adult Yorkshire-cross swine were anesthetized and instrumented with an REBOA catheter, femoral multistage venous cannula, and proximal/distal blood pressure monitoring. Hemodynamics during terminal blood extraction was supported with hand-titrated partial REBOA. Blood samples were taken at set time points for analysis. RESULTS: The median collected blood volume was 3912 mL, with all animals surviving through the planned blood collection of 60% estimated total blood volume (ETBV). Median lactate and potassium levels remained within normal limits for swine through collection of 40% of the ETBV. Median hemoglobin through collection of 40% ETBV did not significantly change from values measured at the start of hemorrhage. CONCLUSIONS: This method of whole blood extraction provided sufficient blood volume and blood quality appropriate for transfusion through 40% ETBV, with remaining collected blood likely still acceptable for allogeneic transfusion despite increased lactate levels. This method of whole blood extraction can efficiently provide a large volume of quality blood to support resuscitation for subsequent uncontrolled hemorrhage models.

Dosimetric effects of rotational errors for single isocenter multiple targets in HyperArc plans: A phantom and retrospective imaging analysis study.

PURPOSE: This study uses a phantom to investigate the dosimetric impact of rotational setup errors for Single Isocenter Multiple Targets (SIMT) HyperArc plans. Additionally, it evaluates intra-fractional rotational setup errors in patients treated with Encompass immobilization system. METHODS: The Varian HyperArc system (Varian Medical systems) was used to create plans targeting spherical PTVs with diameters of 5, 10, and 15 mm and with offsets of 1.3-5.3 cm from the isocenter. Dosimetric parameters, including mean and maximum dose, D99% and D95% were evaluated for various rotational setup errors ranging from 0.5° to 2° for the PTVs and certain CTVs created within PTVs. These rotational errors were applied in an order and direction that resulted in the maximum displacement of targets. The rotation was applied both uniformly around all three axes and individually around each axis. Furthermore, to link the findings to actual treatment scenarios, the intra-fractional rotational setup errors were obtained for stereotactic cranial patients treated with the Encompass system using CBCT images acquired during treatments. RESULTS: The maximum displacement of 2.7 mm was observed for targets located at 4.4 and 4.5 cm from the isocenter with rotational setup errors of 2°. The dose reduction for D99% values corresponding to this displacement were about 50%, 40%, and 30% for PTVs with diameters of 5, 10, and 15 mm, respectively. Both D99% and D95% showed a consistent trend of dose reduction across various rotational errors and PTV volumes. While the maximum dose remained consistent for different targets with various rotational errors, the mean dose decreased by approximately 25%, 12%, and 6% for PTVs with diameters of 5, 10, and 15 cm, respectively, with rotational errors of 2°. In addition, by analyzing CBCT images, the absolute mean rotational setup errors obtained during treatment with Encompass for pitch, roll, and yaw were 0.17° ± 0.13°, 0.11° ± 0.10°, and 0.12° ± 0.10° respectively. This data, combined with existing studies, suggest that a 0.5° rotational setup error is a safe choice to consider for calculating additional PTV margin to ensure adequate CTV coverage. Therefore, the assessment of maximum displacement and dosimetric parameters in this study, for a 0.5° rotational error, highlights the need for an additional 0.7 mm PTV margin for targets positioned at distances of 4.4 cm or greater from the isocenter. CONCLUSIONS: For SIMT Plans, a 0.5° rotational setup error is recommended as a basis for calculating additional PTV margins to ensure adequate CTV coverage when using the Encompass system.

Survey of the infant male urobiome and genomic analysis of Actinotignum spp.

The urinary bladder harbors a community of microbes termed the urobiome, which remains understudied. In this study, we present the urobiome of healthy infant males from samples collected by transurethral catheterization. Using a combination of enhanced culture and amplicon sequencing, we identify several common bacterial genera that can be further investigated for their effects on urinary health across the lifespan. Many genera were shared between all samples suggesting a consistent urobiome composition among this cohort. We note that, for this cohort, early life exposures including mode of birth (vaginal vs. Cesarean section), or prior antibiotic exposure did not influence urobiome composition. In addition, we report the isolation of culturable bacteria from the bladders of these infant males, including Actinotignum spp., a bacterial genus that has been associated with urinary tract infections in older male adults. Herein, we isolate and sequence 9 distinct strains of Actinotignum spp. enhancing the genomic knowledge surrounding this genus and opening avenues for delineating the microbiology of this urobiome constituent. Furthermore, we present a framework for using the combination of culture-dependent and sequencing methodologies for uncovering mechanisms in the urobiome.

Insult of Ultraendurance Events on Blood Pressure: A Systematic Review and Meta-Analysis.

The rise of ultraendurance sports in the past two decades warrants evaluation of the impact on the heart and vessels of a growing number of athletes participating. Blood pressure is a simple, inexpensive method to evaluate one dimension of an athlete's cardiovascular health. No systematic review or meta-analysis to date has chronicled and delineated the effects of ultraendurance races, such as ultramarathons, marathons, half-marathons, and Ironman triathlon events, specifically on heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and mean arterial pressure (MAP) measurements in supine and standing positions before and after the event. This meta-analysis reviews the effects of ultraendurance events on positional and calculated hemodynamic values. Data were extracted from 38 studies and analyzed using a random effects model with a total of 1,645 total blood pressure measurements. Of these, 326 values were obtained from a standing position, and 1,319 blood pressures were taken supine. Pre-race and post-race measurements were evaluated for clinical significance using established standards of hypotension and orthostasis. HR and calculated BP features, such as PP and MAP, were evaluated. Across all included studies, the mean supine post-race HR increased by 21±8 beats per minute (bpm) compared to pre-race values. The mean standing post-race HR increased by 23±14 bpm when compared with pre-race HR. Overall, there was a mean SBP decrease of 19±9 mmHg and a DBP decrease of 9±5 mmHg post-race versus pre-race values. MAP variations reflected SBP and DBP changes. The mean supine and standing pre-race blood pressures across studies were systolic (126±7; 124±14) and diastolic (76±6; 75±12), suggesting that some athletes may enter races with existing hypertension. The post-race increase in the mean HR and decline in mean blood pressure across examined studies suggest that during long-term events, ultramarathon athletes perform with relatively asymptomatic hypotension.

Beaver Tail Liver: A Rare Anatomic Variant.

Beaver tail liver is a rare hepatic anatomical variant in which the left hepatic lobe extends into the left upper quadrant and surrounds the spleen. This extension of the left hepatic lobe consists of normal hepatic parenchyma with no functional liver impairment. In trauma cases, however, the extended left hepatic lobe is vulnerable to injury and confused for a splenic injury due to similar echogenicities and densities on ultrasound and CT. It is also misdiagnosed as a splenic subcapsular hematoma, perisplenic hemorrhage, or mass. Usually, the beaver tail liver is encountered incidentally in patients. We present a 67-year-old male with a history of chronic obstructive lung disease, coronary artery disease, myocardial infarction, and aortic valve replacement. The patient was admitted for further evaluation and placed under the Baker Act for attempting to overdose on oxycodone to commit suicide. Initial imaging identified an ill-defined lesion on CT angiography, which raised concerns for potential malignancy of the liver. Ultimately, an MRI of the abdomen ruled out a malignant lesion due to a lack of abnormal contrast enhancement over the circumscribed region. Consequently, further imaging of the liver led to the incidental discovery of the beaver tail liver in this patient. Due to the rarity of this variant, available literature regarding beaver tail liver is limited to several case reports describing it as an incidental finding. This case highlights the rare nature and unique challenges the beaver tail liver presents for emergency medicine physicians, surgeons, and radiologists interpreting imaging studies without knowledge of its existence. It is important to emphasize how the unexpected presence of the left hepatic lobe in the upper left quadrant of the abdomen can lead to misinterpretations in FAST (focused assessment with sonography in trauma) exams and CT scans. Using non-invasive tools, such as color Doppler, is one way to reduce the incorrect diagnosis of hepatic anatomic variants.

Periventricular Leukomalacia Following Bowel Resection for Necrotizing Enterocolitis in a Premature Neonate.

Necrotizing enterocolitis (NEC) and periventricular leukomalacia (PVL) are relatively common conditions in premature infants with low birth weight (VLBW). However, in the current literature, there are limited case reports of patients with concomitant NEC and PVL. We report a case of a premature female born at a gestational age of 25 weeks and five days who developed cystic intracranial lesions after emergent bowel resection due to NEC. Transcranial ultrasound and magnetic resonance imaging confirmed the presence of cystic PVL in the right middle cerebral artery distribution. Several observational studies note the association between spontaneous intestinal perforation, surgical NEC, and the presence of cystic PVL. When infants are unresponsive to medical management for NEC, exploratory laparotomy with resection of the necrotic or perforated intestine is indicated. However, infants treated surgically have poorer neurodevelopmental outcomes than those with medical therapy. Pathogenesis of neurodevelopmental impairment in preterm infants undergoing surgery involves dysfunctional cerebrovascular autoregulation (CAR), which is associated with harmful changes in cerebral perfusion that lead to neuronal injury. Ill preterm infants, such as those with NEC, cannot regulate cerebral perfusion appropriately, and impaired CAR may be present in more than half the preterm infants during laparotomy. Impaired CAR leads to poor cerebral perfusion that potentiates neuronal injury, such as PVL. This case also brings awareness to the need for adherence to screening practices for white matter injury in critical NICU patients through cost-effective transcranial ultrasound.

Investigating the variability in pressure-volume relationships during hemorrhage and aortic occlusion.

Introduction: The pressure-volume (P-V) relationships of the left ventricle are the classical benchmark for studying cardiac mechanics and pumping function. Perturbations in the P-V relationship (or P-V loop) can be informative and guide the management of heart failure, hypovolemia, and aortic occlusion. Traditionally, P-V loop analyses have been limited to a single-beat P-V loop or an average of consecutive P-V loops (e.g., 10 cardiac cycles). While there are several algorithms to obtain single-beat estimations of the end-systolic and end-diastolic pressure-volume relations (i.e., ESPVR and EDPVR, respectively), there remains a need to better evaluate the variations in P-V relationships longitudinally over time. This is particularly important when studying acute and transient hemodynamic and cardiac events, such as active hemorrhage or aortic occlusion. In this study, we aim to investigate the variability in P-V relationships during hemorrhagic shock and aortic occlusion, by leveraging on a previously published porcine hemorrhage model. Methods: Briefly, swine were instrumented with a P-V catheter in the left ventricle of the heart and underwent a 25% total blood volume hemorrhage over 30 min, followed by either Zone 1 complete aortic occlusion (i.e., REBOA), Zone 1 endovascular variable aortic control (EVAC), or no occlusion as a control, for 45 min. Preload-independent metrics of cardiac performance were obtained at predetermined time points by performing inferior vena cava occlusion during a ventilatory pause. Continuous P-V loop data and other hemodynamic flow and pressure measurements were collected in real-time using a multi-channel data acquisition system. Results: We developed a custom algorithm to quantify the time-dependent variance in both load-dependent and independent cardiac parameters from each P-V loop. As expected, all pigs displayed a significant decrease in the end-systolic pressures and volumes (i.e., ESP, ESV) after hemorrhage. The variability in response to hemorrhage was consistent across all three groups. However, upon introduction of REBOA, we observed significantly high levels of variability in both load-dependent and independent cardiac metrics such as ESP, ESV, and the slope of ESPVR (Ees). For instance, pigs receiving REBOA experienced a 342% increase in ESP from hemorrhage, while pigs receiving EVAC experienced only a 188% increase. The level of variability within the EVAC group was consistently less than that of the REBOA group, which suggests that the EVAC group may be more supportive of maintaining healthier cardiac performance than complete occlusion with REBOA. Discussion: In conclusion, we successfully developed a novel algorithm to reliably quantify the single-beat and longitudinal P-V relations during hemorrhage and aortic occlusion. As expected, hemorrhage resulted in smaller P-V loops, reflective of decreased preload and afterload conditions; however, the cardiac output and heart rate were preserved. The use of REBOA and EVAC for 44 min resulted in the restoration of baseline afterload and preload conditions, but often REBOA exceeded baseline pressure conditions to an alarming level. The level of variability in response to REBOA was significant and could be potentially associated to cardiac injury. By quantifying each P-V loop, we were able to capture the variability in all P-V loops, including those that were irregular in shape and believe that this can help us identify critical time points associated with declining cardiac performance during hemorrhage and REBOA use.

Viability of the virtual cone technique using a fixed small multi-leaf collimator field for stereotactic radiosurgery of trigeminal neuralgia.

Dosimetric uncertainties in very small (≤1.5 × 1.5 cm2 ) photon fields are remarkably higher, which undermines the validity of the virtual cone (VC) technique with a diminutive and variable MLC fields. We evaluate the accuracy and reproducibility of the VC method with a very small, fixed MLC field setting, called a fixed virtual cone (fVC), for small target radiosurgery such as trigeminal neuralgia (TGN). The fVC is characterized by 0.5 cm x 0.5 cm high-definition (HD) MLC field of 10MV FFF beam defined at 100 cm SAD, while backup jaws are positioned at 1.5 cm x 1.5 cm. A spherical dose distribution equivalent to 5 mm (diameter) physical cone was generated using 10-14 non-coplanar, partial arcs. Dosimetric accuracy was validated using SRS diode (PTW 60018), SRS MapCHECK (SNC) measurements. As a quality assurance measure, 10 treatment plans (SRS) for TGN, consisting of various arc ranges at different collimator angles were analyzed using 6 MV FFF and 10 MV FFF beams, including a field-by-field study (n = 130 fields). Dose outputs were compared between the Eclipse TPS and measurements (SRS MapCHECK). Moreover, dosimetric changes in the field defining fVC, prompted by a minute (± 0.5-1.0 mm) leaf shift, was examined among TPS, diode measurements, and Monte Carlo (MC) simulations. The beam model for fVC was validated (≤3% difference) using SRS MapCHECK based absolute dose measurements. The equivalent diameters of the 50% isodose distribution were found comparable to that of a 5 mm cone. Additionally, the comparison of field output factors, dose per MU between the TPS and SRS diode measurements using the fVC field, including ± 1 mm leaf shift, yielded average discrepancies within 5.5% and 3.5% for 6 MV FFF and 10 MV FFF beams, respectively. Overall, the fVC method is a credible alternative to the physical cone (5 mm) that can be applied in routine radiosurgical treatment of TGN.

Viral community composition of hypersaline lakes.

Despite their widespread distribution and remarkable antiquity no RNA viruses definitively associated with the domain Archaea have been identified. In contrast, 17 families of DNA viruses are known to infect archaea. In an attempt to uncover more of the elusive archaeal virosphere, we investigated the metatranscriptomes of hypersaline lakes that are a rich source of archaea. We sequenced RNA extracted from water filter samples of Lake Tyrrell (Victoria, Australia) and cultures seeded from four lakes in Antarctica. To identify highly divergent viruses in these data, we employed a variety of search tools, including Hidden Markov models (HMMs) and position-specific scoring matrices (PSSMs). From this, we identified 12 highly divergent, RNA virus-like candidate sequences from the virus phyla Artverviricota, Duplornaviricota, Kitrinoviricota, Negarnaviricota, and Pisuviricota, including those with similarity to the RNA-dependent RNA polymerase (RdRp). An additional analysis with an artificial intelligence (AI)-based approach that utilises both sequence and structural information identified seven putative and highly divergent RdRp sequences of uncertain phylogenetic position. A sequence matching the Pisuviricota from Deep Lake in Antarctica had the strongest RNA virus signal. Analyses of the dinucleotide representation of the virus-like candidates in comparison to that of potential host species were in some cases compatible with an association to archaeal or bacterial hosts. Notably, however, the use of archaeal CRISPR spacers as a BLAST database failed to detect any RNA viruses. We also described DNA viruses from the families Pleolipoviridae, Sphaerolipoviridae, Halspiviridae, and the class Caudoviricetes. Although we were unable to provide definitive evidence the existence of an RNA virus of archaea in these hypersaline lakes, this study lays the foundations for further investigations of highly divergent RNA viruses in natural environments.

Prevalence of hypercalcemia in primary hypoadrenocorticism in dogs: Multicenter, retrospective study.

BACKGROUND: Hypoadrenocorticism is an important differential for hypercalcemia. The etiology of hypercalcemia in hypoadrenocorticism in dogs is unclear. OBJECTIVE: To review the prevalence of hypercalcemia and use statistical models to identify clinical, demographic, and biochemical variables associated with hypercalcemia in dogs with primary hypoadrenocorticism. ANIMALS: One hundred ten dogs with primary hypoadrenocorticism; 107 with recorded total calcium (TCa), 43 recorded ionized calcium (iCa). METHODS: Multicenter retrospective observational study at 4 UK referral hospitals. Univariable logistic regression analyses were performed to assess the association between independent variables of signalment, hypoadrenocorticism type (glucocorticoid only deficient hypoadrenocorticism [GHoC] vs glucocorticoid and mineralocorticoid deficient hypoadrenocorticism [GMHoC]), clinicopathological variables and hypercalcemia. Hypercalcemia was defined as elevated TCa, an elevated iCa, or both elevated TCa and iCa (Model 1) or as elevated iCa (Model 2). RESULTS: Overall prevalence of hypercalcemia was 34.5% (38/110). The odds of hypercalcemia (Model 1) were increased (P < .05) in dogs with GMHoC ([vs GHoC], OR [odds ratio] = 3.86, 95% confidence interval [CI] 1.105-13.463), higher serum creatinine (OR = 1.512, 95% CI 1.041-2.197), and higher serum albumin (OR = 4.187, 95% CI 1.744-10.048). The odds of ionized hypercalcemia (Model 2) were increased (P < .05) with reduced serum potassium concentration (OR = 0.401, 95% CI 0.184-0.876) and younger age (OR = 0.737, 95% CI 0.558-0.974). CONCLUSIONS AND CLINICAL IMPORTANCE: This study identified several key clinical and biochemical variables associated with hypercalcemia in dogs with primary hypoadrenocorticism. These findings aid understanding of the pathophysiology and etiology of hypercalcemia in dogs with primary hypoadrenocorticism.