Quantifying the benefit of whole blood on mortality in trauma patients requiring emergent laparotomy.

BACKGROUND: Whole blood (WB) transfusions in trauma represent an increasingly utilized resuscitation strategy in trauma patients. Previous reports suggest a probable mortality benefit with incorporating WB into massive transfusion protocols. However, questions surrounding optimal WB practices persist. We sought to assess the association between the proportion of WB transfused during the initial resuscitative period and its impact on early mortality outcomes for traumatically injured patients. METHODS: We performed a retrospective analysis of severely injured patients requiring emergent laparotomy and ≥ 3 units of red blood cell containing products (WB or packed red blood cells) within the first hour from an ACS Level 1 Trauma Center (2019-2022). Patients were evaluated based on the proportion of WB they received compared to packed red blood cells during their initial resuscitation (high ratio cohort ≥50% WB vs low ratio cohort <50% WB). Multilevel Bayesian regression analyses were performed to calculate the posterior probabilities and risk ratios (RR) associated with a WB predominant resuscitation for early mortality outcomes. RESULTS: 266 patients were analyzed (81% male, mean age of 36 years old, 61% penetrating injury, mean ISS of 30). The mortality was 11% at 4-hours and 14% at 24-hours. The high ratio cohort demonstrated a 99% (RR 0.12; 95% CrI 0.02-0.53) and 99% (RR 0.22; 95% CrI 0.08-0.65) probability of decreased mortality at 4-hours and 24-hours, respectively, compared the low ratio cohort. There was a 94% and 88% probability of at least a 50% mortality relative risk reduction associated with the WB predominate strategy at 4 hours and 24 hours, respectively. CONCLUSION: Preferential transfusion of WB during the initial resuscitation demonstrated a 99% probability of being superior to component predominant resuscitations with regards to 4 and 24-hour mortality suggesting that WB predominant resuscitations may be superior for improving early mortality. Prospective, randomized trials should be sought. LEVEL OF EVIDENCE: Therapeutic, Level III.

Mortality in hypotensive combat casualties who require emergent laparotomy in the forward deployed environment.

INTRODUCTION: Mortality rates among hypotensive civilian patients requiring emergent laparotomy exceed 40%. Damage control (DCR) principles were incorporated into the military's Clinical Practice Guidelines (CPG) in 2008. We examined combat casualties requiring emergent laparotomy to characterize how mortality rates compare to hypotensive civilian trauma patients. METHODS: The DoD Trauma Registry (2004-2020) was queried for adults who underwent combat laparotomy. Patients who were hypotensive were compared to normotensive patients. Mortality was the outcome of interest. Mortality rates before (2004-2007) and after (2009-2020) DCR CPG implementation were analyzed. RESULTS: 1051 patients were studied. Overall mortality was 6.5% for normotensive casualties and 28.7% for hypotensive casualties. Mortality decreased in normotensive patients but remained unchanged in hypotensive patients following the implementation of the DCR CPG. CONCLUSION: Hypotensive combat casualties undergoing emergent laparotomy demonstrated a mortality rate of 29.5%. Despite many advances, mortality rates remain high in hypotensive patients requiring emergent laparotomy.

The use of mobile thermal imaging and machine learning technology for the detection of early surgical site infections.

BACKGROUND: Surgical Site Infections (SSI) yield subtle, early signs that are not readily identifiable. This study sought to develop a machine learning algorithm that could identify early SSIs based on thermal images. METHODS: Images were taken of surgical incisions on 193 patients who underwent a variety of surgical procedures. Two neural network models were generated to detect SSIs, one using RGB images, and one incorporating thermal images. Accuracy and Jaccard Index were the primary metrics by which models were evaluated. RESULTS: Only 5 patients in our cohort developed SSIs (2.8%). Models were instead generated to demarcate the wound site. The models had 89-92% accuracy in predicting pixel class. The Jaccard indices for the RGB and RGB â€‹+ â€‹Thermal models were 66% and 64%, respectively. CONCLUSIONS: Although the low infection rate precluded the ability of our models to identify surgical site infections, we were able to generate two models to successfully segment wounds. This proof-of-concept study demonstrates that computer vision has the potential to support future surgical applications.

Effects of Gynecomastia Surgery on Readiness and Return to Duty in an Active Duty Military Population.

INTRODUCTION: Simple mastectomies are routinely performed in the military health care system as gynecomastia can cause significant pain and discomfort when wearing body armor. Postoperative recovery negatively impacts personnel readiness. In this study, we sought to study time to return to duty in active duty service members who undergo surgery for gynecomastia. METHODS AND MATERIALS: We conducted a single-center retrospective review of active duty patients undergoing a surgical operation for gynecomastia from July 2020-June 2022. A total of 96 patients were included. Our primary outcome of interest was time from surgery to return to duty. A multivariate analysis was performed to assess for factors independently associated with surgical complications including patient demographics and operative techniques. RESULTS: The median number of days to return to duty after surgery was 28 days (IQR 13-37). The median loss of duty days because of gynecomastia without surgery was 19 days (IQR 10-21), which was different on the Mann-Whitney U test. Surgical complications were observed in 19 patients (19.7%) with the most common complications being seroma (11), hematoma (4), nipple-areolar complex necrosis (2), and infection (2). Patients with a complication have significantly more time to return to duty (28 vs. 49 days, P < .001). Risk factors associated with an increased risk of complication include ranks E1-E4, behavioral health diagnosis, "open" vs. "combined" technique with liposuction, length of operation greater than 58 minutes, and excised breast mass greater than 17.9 g. CONCLUSIONS: Gynecomastia surgery is associated with a detriment to personnel readiness. Surgery should be reserved for patients with severe symptoms that prevent the performance of daily duties. Furthermore, factors associated with an increased risk for complications include ranks E1-E5, behavioral health diagnosis, length of operation >58 minutes, and excised breast mass >17.9 g. The operating surgeon should be mindful of these factors.

The risks of sedation and pain control during burn resuscitation: Increased opioids lead to over-resuscitation and hypotension.

INTRODUCTION: Pain management and sedation are necessary in severely burned persons. Balancing pain control, obtundation, and hemodynamic suppression can be challenging. We hypothesized that increased sedation during burn resuscitation is associated with increased intravenous fluid administration and hemodynamic instability. METHODS: A retrospective review of a single burn center was performed from 2014 to 2019 for all admissions to the burn unit with > 20% total body surface area (TBSA) burns. Within 48 h of admission, we compared total amounts of sedation/pain medications (morphine milligram equivalents (MME), propofol, dexmedetomidine, benzodiazepines) with total resuscitation volumes and frequency of hypotensive episodes. Resuscitation volumes and frequency of hypotension were modeled with multivariable linear regression adjusting for burn severity and weight. RESULTS: 208 patients were included with median age of 43 years (IQR 29-55) and median %TBSA of 31 (IQR 25-44). Median 48-hour resuscitation milliliters per weight per %TBSA were 3.3 (IQR 2.28-4.92). Pain/sedative medications included a combination of opioids in 99%, benzodiazepines in 73%, propofol in 31%, and dexmedetomidine in 11% of patients. MMEs were associated with greater resuscitation volumes (95% CI: 0.15-0.54, p = 0.01) as well as number of hypotensive events (95% CI: 1.57-2.7, p < 0.001). No associations were noted with other sedative medications when comparing the number of hypotensive events and resuscitation volumes. CONCLUSIONS: Increased opioid administration has physiological consequences and should be carefully monitored during resuscitation as higher volume administrations lead to worse outcomes. Opioids and sedating medications should be titrated to the least amount needed to achieve reasonable comfort and sedation.

Chronic Nerve Root Injury in Pediatric Patients With Chronic Lumbar Stress Fractures: A Retrospective Review.

INTRODUCTION: Many orthopedic providers currently treat chronic spondylolysis as self-limited fractures. While the condition has previously been associated with back pain in pediatrics, there has been little attention on the risk of neurologic harm. Electromyography (EMG) is a common study used to evaluate nerve injury, but it has not been previously reported for testing pediatric patients with stress fractures. In this study, pediatric patients with chronic pars fractures and muscle extremity weakness who underwent EMG testing were reviewed to analyze their risk of chronic nerve injury. METHODS: 120 pediatric patients who underwent EMG testing between 2015 and 2021 were analyzed, and 41(21F,20M) patients with a mean age of 16(13-20) met criteria of chronic lumbar pediatric spondylolysis with weakness on ankle dorsiflexion or plantarflexion. No exclusions were made. Initial EMG testing was indicated for the extremity weakness; pain was not the major concern. All exams were completed by JWM. Thin-cut lumbar CT studies were done at the same institution, and EMGs were completed by one of three physiatrists. EMGs were determined as normal, abnormal but not meeting chronic nerve injury threshold, or abnormal and meeting threshold for chronic nerve injury. RESULTS: Of the 41 patients, 33 had bilateral and 8 had unilateral fractures with 95% (39/41) of them located at L4 or L5. 55% (18/33) of the bilateral fractures had abnormal EMGs and demonstrated chronic nerve injury; 1 had an abnormal EMG but did meet chronic injury threshold. 75% (6/8) of the unilateral fractures had abnormal EMGs and demonstrated chronic nerve injury; 1 had an abnormal EMG but did meet chronic injury threshold. Overall, 36% (15/41) had normal EMGs, 5% (2/41) had abnormal results but did not reach chronic injury threshold, and 59% (24/41) met threshold for chronic nerve injury. CONCLUSION: Chronic pars fractures have historically been treated as a benign and self-limited sports injury. However, our analysis showed that 59% of adolescent patients presenting with chronic pars fractures and dorsiflexion or plantarflexion weakness have developed a chronic nerve injury. This study is the first to demonstrate the risk of neurologic harm in unhealed pediatric lumbar stress fractures, and it indicates the importance of EMG testing in young patients presenting with chronic spondylolysis and extremity weakness.

Rapid cold sterilization of 3D printed surgical instruments for the austere environment.

INTRODUCTION: Medical operations are vulnerable to global supply chain fluctuations. The ability to locally produce and reliably sterilize medical equipment may mitigate this risk. This project developed a reliable high-level disinfection process for 3D printed surgical tools. METHODS: Surgical instruments and consumables were designed and printed from various materials. Devices contaminated with known and unknown bacteria underwent one of three cleaning methods followed by high-level disinfection using submersion in a Cidex OPA Solution. Devices were then cultured on blood agar plates and incubated for 48 h. Positive and negative controls were performed. RESULTS: The results of control experiments showed no growth on negative controls and significant growth on all positive control plates. Of the three cleaning methods tested, one showed no growth: cleaning with isopropyl alcohol and chlorhexidine followed by Cidex bath. DISCUSSION: This project successfully developed a rapid high-level disinfection process for 3D printed surgical instruments made from two different types of 3D printing material.

Early Use of Extracorporeal Membrane Oxygenation for Traumatically Injured Patients: A National Trauma Database Analysis.

INTRODUCTION: Extracorporeal membrane oxygenation (ECMO) in acute trauma patients is a poorly characterized event. While ECMO most commonly has been deployed for advanced cardiopulmonary or respiratory failure following initial resuscitation, growing levels of evidence for out of hospital cardiac arrest support early ECMO cannulation as part of resuscitative efforts. We sought to perform a descriptive analysis evaluating traumatically injured patients, who were placed on ECMO, during their initial resuscitation period. METHODS: We performed a retrospective analysis of the Trauma Quality Improvement Program Database from 2017 to 2019. All traumatically injured patients who received ECMO within the first 24 hours of their hospitalization were assessed. Descriptive statistics were used to define patient characteristics and injury patterns associated with the need for ECMO, while mortality represented the primary outcome evaluated. RESULTS: A total of 696 trauma patients received ECMO during their hospitalization, of which 221 were placed on ECMO within the first 24 hours. Early ECMO patients were on average 32.5 years old, 86% male, and sustained a penetrating injury 9% of the time. The average ISS was 30.7, and the overall mortality rate was 41.2%. Prehospital cardiac arrest was noted in 18.2% of the patient population resulting in a 46.8% mortality. Of those who underwent resuscitative thoracotomy, a 53.3% mortality rate was present. CONCLUSION: Early cannulation for ECMO in severely injured patients may provide an opportunity for rescue therapy following severe injury patterns. Further evaluation regarding the safety profile, cannulation strategies, and optimal injury patterns for these techniques should be evaluated.

Modern Statistical Methods for the Surgeon Scientist: The Clash of Frequentist versus Bayesian Paradigms.

The practice of evidence-based medicine is the result of a multitude of research and trials aimed toward improving health-care outcomes. An understanding of the associated data remains paramount toward optimizing patient outcomes. Medical statistics commonly revolve around frequentist concepts that are convoluted and nonintuitive for nonstatisticians. Within this article, we will discuss frequentist statistics, their limitations, as well as introduce Bayesian statistics as an alternative approach for data interpretation. By doing so, we intend to highlight the importance of correct statistical interpretations through clinically relevant examples while providing a deeper understanding of the underlying philosophies of frequentist and Bayesian statistics.

Airborne! UAV delivery of blood products and medical logistics for combat zones.

BACKGROUND: Innovative solutions to resupply critical medical logistics and blood products may be required in future near-peer conflicts. Unmanned aerial vehicles (UAVs) are increasingly being used in austere environments and may be a viable platform for medical resupply and the transport of blood products. METHODS: A literature review on PubMed and Google Scholar up to March of 2022 yielded a total of 27 articles that were included in this narrative review. The objectives of this article are to discuss the current limitations of prehospital blood transfusion in military settings, discuss the current uses of UAVs for medical logistics, and highlight the ongoing research surrounding UAVs for blood product delivery. DISCUSSION: UAVs allow for the timely delivery of medical supplies in numerous settings and have been utilized for both military and civilian purposes. Investigations into the effects of aeromedical transportation on blood products have found minimal blood product degradation when appropriately thermoregulated and delivered in a manner that minimizes trauma. UAV delivery of blood products is now actively being explored by numerous entities around the globe. Current limitations surrounding the lack of high-quality safety data, engineering constraints over carrying capacity, storage capability, and distance traveled, as well as air space regulations persist. CONCLUSION: UAVs may offer a novel solution for the transport of medical supplies and blood products in a safe and timely manner for the forward-deployed setting. Further research on optimal UAV design, optimal delivery techniques, and blood product safety following transport should be explored prior to implementation.

Impact of COVID on surgical case volume at military treatment facilities with surgical residencies.

INTRODUCTION: The Military Health System (MHS) is tasked with the dual mission of providing medical care to beneficiaries while ensuring medical readiness. MHS provides care through a combination of military treatment facilities (MTF) ("direct care"; DC) & off-base civilian facilities ("purchased care"; PC). Given recent concerns regarding low surgical volume at MTFs, we sought to evaluate COVID's impact on elective and non-elective case volume at MTFs with surgical residencies. METHODS: Retrospective review of 2017-2021 M2 database was performed on Tricare beneficiaries who underwent bariatric surgery or major colorectal surgery in the DC or PC market at, or, surrounding MTFs with surgical residencies. Procedures were identified using ICD-10 procedure codes and Medicare severity-diagnosis related groups. A detailed analysis was then performed on changes in case volume in the DC and PC markets. RESULTS: 5,698 bariatric and 5,517 major colorectal procedures were performed during the study period. There was an 84% vs 20% quarterly decrease in elective bariatric surgeries completed in the DC and PC markets from Q1 to Q2 2020. Pre to post-COVID (Q1 2017 - Q1 2020 vs Q3 2020 - Q4 2021) there was a decrease in the percentage of bariatric surgeries completed in the DC market (74.1% vs 55.0%, p = 0.001). Meanwhile, major colorectal surgery quarterly case volume remained unchanged in the DC (137 vs 125, p = 0.18) and PC (146 v 137, p = 0.13) markets, pre- and post-COVID. DISCUSSION: Bariatric surgical case volume at MTFs disproportionately decreased during COVID when compared to the PC market and major colorectal cases. Bariatric case volume has rebounded in PC markets surpassing pre-COVID levels while DC case volume remains depressed. Further attention is warranted regarding decreased elective surgical case volume at MTFs.

Burn Outcomes at Extremes of Body Mass Index: Underweight Is as Problematic as Morbid Obesity.

Limited evidence suggests that obesity adversely affects burn outcomes. However, the impacts of body mass index (BMI) across the continuum have not been fully characterized. Therefore, we aimed to characterize outcomes after burn injury across the BMI continuum. We hypothesized that "normal" BMI (18.5-24.9) would have the lowest mortality and complication rates. The US National Trauma Data Bank (NTDB) was queried for adult burn-injured patients from 2007 to 2015. Admission BMI was calculated and grouped according to World Health Organization (WHO) classification. The primary outcome was in-hospital mortality. Secondary outcomes of time to wound closure, length of stay, and inpatient complications were similarly assessed. Of the 116,008 burn patient encounters that were identified, 7243 underwent at least one operation for wound closure. Mortality was lowest in the overweight (P = .039) and obese I cohorts (BMI 25-29.9, 30.0-34.9) at 2.9% and increased in both directions of the BMI continuum to 4.1% in the underweight (P = .032) and 5.1% in the morbidly obese (class III) group (P = .042). Time to final wound closure was longest in the two BMI extremes. BMI ≥40 was associated with increased intensive care unit days, ventilator days, renal and cardiac complications. BMI <18.5 had increased hospital days and rates of sepsis. Aberrations in metabolism associated with both increases and decreases of body weight may cause pathophysiologic changes that lead to worsened outcomes in burn-injured patients. In addition to morbidly obese patients, underweight patients also experience increased burn-related death and complications. In contrast, overweight BMI patients may have greater physiologic reserves without the burden of obesity or sarcopenia.

Safety code blue! Assessing the use of blue surgical sterilization wrap for homemade respirator masks during the COVID-19 crisis.

The use of surgical sterilization wrap for respirator masks during the COVID-19 crisis has become a popularized personal protective equipment alternative option due to claims supporting its ability to meet N95 standards. This study sought to assess these claims using standardized filter testing. The tested material failed to meet N95 standards and suggests its use may place medical personnel at increased risk of harm when managing COVID-19 patients.

Quality Assurance During a Global Pandemic: An Evaluation of Improvised Filter Materials for Healthcare Workers.

OBJECTIVE: The proliferation of improvised masks during the COVID-19 pandemic has raised questions regarding filter effectiveness and safety. We sought to compare the effectiveness of commonly used improvised filter materials against N95 industry standards. METHODS: Six different filter materials commonly used in the community were tested using both single- and multi-layer configurations with the TSI 8130 automated filter tester in accordance with National Institute for Occupational Safety and Health (NIOSH) standards for N95 respirators. RESULTS: Only three of the tested filter material configurations met N95 parameters with regard to filtration efficiency and pressure drop across the filter material-the: True-high-efficiency particulate air (HEPA) filter, four-layer MERV 13 and 14 HVAC filters. CONCLUSIONS: Many proposed filter materials for improvised masks do not meet current industry standards and may pose safety and efficacy concerns. Care should be taken when selecting materials for this critical respirator component, particularly for health care workers or others at high risk for pathogen exposure.

Variations in Courtesy Authorship Perceptions and Practices Among Modern Surgical Journals: The Generation Gap.

BACKGROUND: Academic journals have adopted strict authorship guidelines to eliminate the addition of authors who have not met criteria, also known as "courtesy authors." We sought to analyze current perceptions, practices, and academic rank-related variations in courtesy authorship use among modern surgical journals. METHODS: Authors who published original research articles in 2014-2015 in eight surgical journals were surveyed and categorized as junior (JF) or senior faculty (SF) by years in practice. Responses regarding courtesy authorship perceptions and practices were analyzed. Subanalyses were performed based on journal impact factor. RESULTS: A total of 455 authors responded (34% JF versus 66% SF). SF were older (52 versus 39 y) and more predominantly male (80% versus 61%) versus JF. JF more frequently added a courtesy author to the index publication versus SF (23% versus 13%, P = 0.02), but had similar historical rates of adding courtesy authors (58% versus 51%, P = not significant) or being added as a courtesy author (29% versus 37%, P = not significant). JF felt courtesy authorship was more common in their practice and felt more pressure by superiors to add courtesy authors. Perceptions regarding the practice of courtesy authorship differed significantly, with 70% of JF feeling courtesy authorship use has not declined versus 45% of SF (P < 0.05). Both JF and SF cited courtesy authorship positives, including avoiding author conflicts (17% versus 33%, respectively) and increasing morale (25% versus 45%, respectively). CONCLUSIONS: Courtesy authorship use continues to be common among both JF and SF. However, perceptions about the benefits, harms, and pressures vary significantly by academic rank and with journal impact factor.

Courtesy Authorship in Academic Surgery Publications.

Importance: Courtesy authorship is defined as including an individual who has not met authorship criteria as an author. Although most journals follow strict authorship criteria, the current incidence of courtesy authorship is unknown. Objective: To assess the practices related to courtesy authorship in surgical journals and academia. Design, Setting, and Participants: A survey was conducted from July 15 to October 27, 2017, of the first authors and senior authors of original articles, reviews, and clinical trials published between 2014 and 2015 in 8 surgical journals categorized as having a high or low impact factor. Main Outcomes and Measures: The prevalence of courtesy authorship overall and among subgroups of authors in high impact factor journals and low impact factor journals and among first authors and senior authors, as well as author opinions regarding courtesy authorship. Results: A total of 203 first authors and 254 senior authors responded (of 369 respondents who provided data on sex, 271 were men and 98 were women), with most being in academic programs (first authors, 116 of 168 [69.0%]; senior authors, 173 of 202 [85.6%]). A total of 17.2% of respondents (42 of 244) reported adding courtesy authors for the surveyed publications: 20.4% by first authors (32 of 157) and 11.5% by senior authors (10 of 87), but 53.7% (131 of 244) reported adding courtesy authorship on prior publications and 33.2% (81 of 244) had been added as a courtesy author in the past. Although 45 of 85 senior authors (52.9%) thought that courtesy authorship has decreased, 93 of 144 first authors (64.6%) thought that courtesy authorship has not changed or had increased (P = .03). There was no difference in the incidence of courtesy authorship for low vs high impact factor journals. Both first authors (29 of 149 [19.5%]) and senior authors (19 of 85 [22.4%]) reported pressures to add courtesy authorship, but external pressure was greater for low impact factor journals than for high impact factor journals (77 of 166 [46.4%] vs 60 of 167 [35.9%]; P = .04). More authors in low impact factor journals than in high impact factor journals thought that courtesy authorship was less harmful to academia (55 of 114 [48.2%] vs 34 of 117 [29.1%]). Overall, senior authors reported more positive outcomes with courtesy authorship (eg, improved morale and avoided author conflicts) than did first authors. Conclusions and Relevance: Courtesy authorship use is common by both first and senior authors in low impact factor journals and high impact factor journals. There are different perceptions, practices, and pressures to include courtesy authorship for first and senior authors. Understanding these issues will lead to better education to eliminate this practice.

See one, do one, but never teach one? An analysis of resident teaching assist cases under various levels of attending supervision.

BACKGROUND: Surgical training has traditionally relied on increasing levels of resident autonomy. We sought to analyze the outcomes of senior resident teaching assist (TA) cases performed with a structured policy including varying levels of staff supervision. METHODS: Retrospective review at a military medical center of TA cases from 2009 to 2014. The level of staff supervision included staff scrubbed (SS), staff present and not scrubbed (SP), or staff not present but available (NP). Operative variables were analyzed. An anonymous survey of residents and attendings at 6 military programs regarding experience and opinions on TA cases was distributed. RESULTS: 389 TA cases were identified. The majority (52%) were performed as NP. Operative times were shorter for NP cases (p < 0.05). Overall complication rate and length of stay were not different between groups (p > 0.05). Survey results demonstrated agreement amongst staff and residents that allowing selective NP was critical for achieving resident competence. CONCLUSION: There were no identified adverse effects on intraoperative or postoperative complications. This practice is a critical component of training senior residents to transition to independent practice.

Mobile forward-looking infrared technology allows rapid assessment of resuscitative endovascular balloon occlusion of the aorta in hemorrhage and blackout conditions.

INTRODUCTION: Objective assessment of final resuscitative endovascular balloon occlusion of the aorta (REBOA) position and adequate distal aortic occlusion is critical in patients with hemorrhagic shock, especially as feasibility is being increasingly investigated in the prehospital setting. We propose that mobile forward-looking infrared (FLIR) thermal imaging is a fast, reliable, and noninvasive method to assess REBOA position and efficacy in scenarios applicable to battlefield and prehospital care. METHODS: Ten swine were randomized to a 40% hemorrhage group (H, n = 5) or nonhemorrhage group (NH, n = 5). Three experiments were completed after Zone I placement of a REBOA catheter. Resuscitative endovascular balloon occlusion of the aorta was deployed for 30 minutes in all animals followed by randomized continued deployment versus sham in both light and blackout conditions. Forward-looking infrared images and hemodynamic data were obtained. Images were presented to 62 blinded observers for assessment of REBOA inflation status. RESULTS: There was no difference in hemodynamic or laboratory values at baseline. The H group was significantly more hypotensive (mean arterial pressure 44 vs. 60 mm Hg, p < 0.01), vasodilated (systemic vascular resistance 634 vs. 938dyn·s/cm, p = 0.02), and anemic (hematocrit 12 vs. 23.2%, p < 0.01). Hemorrhage group animals remained more hypotensive, anemic, and acidotic throughout all three experiments. There was a significant difference in the temperature change (ΔTemp) measured by FLIR between animals with REBOA inflated versus not inflated (5.7°C vs. 0.7°C, p < 0.01). The H and NH animals exhibited equal magnitudes of ΔTemp in both inflated and deflated states. Blinded observer analysis of FLIR images correctly identified adequate REBOA inflation and aortic occlusion 95.4% at 5 minutes and 98.8% at 10 minutes (positive predictive value at 5 minutes = 99% and positive predictive value at 10 minutes = 100%). CONCLUSIONS: Mobile thermal imaging is an easy, rapid, and reliable method for assessing distal perfusion after occlusion by REBOA. Smartphone-based FLIR technology allows for confirmation of adequate REBOA placement at the point of care, and performance was not degraded in the setting of major hemorrhage or blackout conditions.

Plasma coadministration improves resuscitation with tranexamic acid or prothrombin complex in a porcine hemorrhagic shock model.

BACKGROUND: Traumatic coagulopathy has now been well characterized and carries high rates of mortality owing to bleeding. A 'factor-based' resuscitation strategy using procoagulant drugs and factor concentrates in lieu of plasma is being used by some, but with little evidentiary support. We sought to evaluate and compare resuscitation strategies using combinations of tranexamic acid (TXA), prothrombin complex concentrate (PCC), and fresh frozen plasma (FFP). METHODS: Sixty adult swine underwent 35% blood volume hemorrhage combined with a truncal ischemia-reperfusion injury to produce uniform shock and coagulopathy. Animals were randomized to control (n = 12), a single-agent group (TXA, n = 10; PCC, n = 8; or FFP, n = 6) or combination groups (TXA-FFP, n = 10; PCC-FFP, n = 8; TXA-PCC, n = 6). Resuscitation was continued to 6 hours. Key outcomes included hemodynamics, laboratory values, and rotational thromboelastometry. Results were compared between all groups, with additional comparisons between FFP and non-FFP groups. RESULTS: All 60 animals survived to 6 hours. Shock was seen in all animals, with hypotension (mean arterial pressure, 44 mm Hg), tachycardia (heart rate, 145), acidosis (pH 7.18; lactate, 11), anemia (hematocrit, 17), and coagulopathy (fibrinogen, 107). There were clear differences between groups for mean pH (p = 0.02), international normalized ratio (p < 0.01), clotting time (CT; p < 0.01), lactate (p = 0.01), creatinine (p < 0.01), and fibrinogen (p = 0.02). Fresh frozen plasma groups had significantly improved resuscitation and clotting parameters (Figures), with lower lactate at 6.5 versus 8.4 (p = 0.04), and increased fibrinogen at 126 versus 95 (p < 0.01). Rotational thromboelastometry also demonstrated shortened CT at 60 seconds in the FFP group vs 65 seconds in the non-FFP group (p = 0.04). CONCLUSION: When used to correct traumatic coagulopathy, combinations of FFP with TXA or PCC were superior in improving acidosis, coagulopathy, and CT than when these agents are given alone or in combination without plasma. Further validation of pure factor-based strategies is needed.

The effects of hemorrhage on the pharmacokinetics of tranexamic acid in a swine model.

BACKGROUND: The early use of tranexamic acid (TXA) is strongly advocated in patients who are likely to require massive transfusion to decrease mortality. This study determines the influence of hemorrhage on the pharmacokinetics of TXA in a porcine model. METHODS: The investigation was a prospective experimental study in Yucatan minipigs. First, in vitro plasma-cell partitioning of TXA was evaluated by inoculating whole blood with known aliquots, centrifuging, and measuring the supernatant with high-performance liquid chromatography with mass spectrometry (HPLC-MS). Then, using in vivo modeling, normovolemic and hypovolemic (35% reduction in blood volume) swine (n = 4 per group) received 1 g of intravenous TXA and had blood sampled at 14 time points over 4 hours to determine baseline clearance via HPLC-MS. Additional swine (n = 4) were hemorrhaged 35% of their blood volume, and TXA was administered as a 15 mg/kg infusion over 10 minutes followed by infusion of 1.875 mg/kg per hour to simulate massive hemorrhage scenario. During the first hour of TXA administration, one total blood volume was hemorrhaged and simultaneously replaced with TXA free blood. Serial blood samples and the hemorrhaged blood were analyzed by HPLC-MS to determine the percentage of dose lost via hemorrhage. RESULTS: Clearance of TXA was diminished in the hypovolemic group compared with the normovolemic group (115 ± 4 vs 70 ± 7 mL/min). Percentage of dose lost via hemorrhage averaged 25%. The lowest measured plasma level during the exchange transfusion was 34 µg/mL. CONCLUSION: Mean 25% of the present 2017 Joint Trauma System Clinical Practice Guideline dosing of TXA can be lost to hemorrhage if a blood volume is transfused within an hour of initiating therapy. In the case of TXA, which has limited distribution and is administered during active hemorrhage and massive blood transfusions, replacement strategies should be developed and tested to find simple methods of adjusting the current dosing guidelines to maintain therapeutic plasma concentrations. LEVEL OF EVIDENCE: Therapeutic, level II.