A novel REBOA system: prototype and proof of concept

Background: Lower torso hemorrhage is a significant cause of death from injuries in combat. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been used to rescue patients successfully in the hospital setting, but its prehospital use is controversial. We designed a device that would be easy to use, safer in injured vessels, migration-resistant and amenable to a prehospital environment. Methods: We designed a novel, balloon-led device using common commercial materials. Thin latex rubber was reassembled in cylindrical conformation aligned to the shape of the aorta and invaginated into vinyl tubing. The catheter is placed into the femoral vessel, followed by expression of the balloon with CO2 inflation in a proximal direction to navigate and treat damaged pelvic vasculature, occluding the distal aorta. The system was tested on model aortas (both intact and injured cadaveric porcine aorta) with inline fluid flow and pressure monitoring to determine the maximum pressure the balloons could occlude. The device was also tested on a perfused human cadaveric model. Results: Flow was occluded with the balloon up to an average of 561.1 ± 124.3 mm Hg. It always ruptured before causing damage to the porcine aorta and was able to occlude injured iliac vessels and proceed to occlude the distal aorta. The device was effective in occluding the distal aorta of a perfused human cadaver. Conclusion: This novel, high-volume, low-pressure device can occlude the distal aorta in a simulated human aorta model, cadaveric porcine model and perfused human cadaver. It can occlude fluid flow to supraphysiologic pressures. It is easy to use, migration-resistant, able to navigate and treat injured pelvic vessels, and amenable to prehospital care.

Contexte: L'hémorragie au bas du corps est une importante cause de décès suite aux blessures subies au combat. L'occlusion aortique endovasculaire par ballonnet a été utilisée avec succès comme mesure de réanimation chez des patients hospitalisés, mais son utilisation dans un contexte préhospitalier est controversée. Nous avons conçu un instrument qui serait facile à utiliser, plus sécuritaire en présence de vaisseaux lésés, peu sujet à migrer et adapté au contexte préhospitalier. Méthodes: Nous avons conçu un nouvel instrument guidé par ballonnet et fabriqué à l'aide de matériaux d'usage courant. Du caoutchouc de latex mince a été façonné en cylindre pour épouser la forme de l'aorte et introduit dans un tube de vinyle. Le cathéter est ensuite inséré dans la veine fémorale, après quoi il est gonflé avec du CO2 en direction proximale pour atteindre et traiter le réseau vasculaire pelvien et créer une occlusion aortique distale. Le système a été mis à l'essai sur des aortes modèles (aortes de cadavres de porcs intactes et lésées), avec surveillance interne du débit et de la pression pour déterminer la pression maximale contre laquelle le ballonnet est capable de créer l'occlusion. L'instrument a aussi été testé sur un modèle de cadavre humain perfusé. Résultats: Le ballonnet a permis l'occlusion à une pression moyenne pouvant atteindre 561,1 ± 124,3 mm Hg. Il s'est toujours rompu avant de pouvoir endommager l'aorte porcine et a permis l'occlusion des vaisseaux iliaques lésés et ensuite de l'aorte distale. L'instrument a permis l'occlusion efficace de l'aorte distale d'un cadavre humain perfusé. Conclusion: Ce nouvel instrument à fort volume et faible pression permet de créer l'occlusion de l'aorte distale dans un modèle simulé d'aorte humaine, dans un modèle de cadavre porcin et sur un cadavre humain perfusé. Il est facile à utiliser, peu susceptible de migrer; il se déploie et traite facilement les vaisseaux pelviens lésés et convient au contexte préhospitalier.

Impact of traumatic upper-extremity amputation on the outcome of injury caused by an antipersonnel improvised explosive device

Background: We have previously reported a higher than expected rate of upper-extremity amputation (UEA) in victims of an antipersonnel improvised explosive device (AP-IED) compared with a similar cohort injured by antipersonnel mines (APM). The goal of this study was to describe the rate, severity and impact of UAE caused by an AP-IED. Methods: We analyzed a prospective database of 100 consecutive dismounted AP-IED victims with pattern 1 injuries to compare the outcomes of the cohort with UEA to that without. Results: We found that UEA (8 above elbow, 19 below elbow, 1 through elbow, 3 hand, 15 digit(s)) was much more prevalent with AP-IED than with APM (40% v. 6%, p < 0.001). In addition, UEA was associated with a higher rate of multiple amputations (39 [98%] v. 32 [53%], p < 0.001), bilateral lower-extremity amputation (LEA; 33 [82.5%] v. 30 [53.3%], p = 0.003) and facial injury (8 [20%] v. 4 [6.4%], p = 0.044), but not with pelvic disruption (10 [25%]), genitoperineal mutilation (19 [48%]), eye injury (6 [15%]), or skull fracture (6 [15%]). The fatality rate was higher in patients with UEA than in those without (12 [30%] v. 7 [12%], p = 0.022). Conclusion: Upper-extremity amputation is more prevalent with AP-IED than APM. Presence of UEA is associated with more severe injury and increased risk of death in AP-IED victims. Upper-limb injury has significant consequences for rehabilitation from LEA, which universally accompanies UEA in AP-IED victims. Upper-extremity injury should be amenable to prevention by innovative personal protective equipment designed to protect the flexed elbow.

Contexte: Nous avons déjà fait état d'un taux plus élevé que prévu d'amputations des membres supérieurs (AMS) chez les victimes d'engins explosifs artisanaux (EEA) comparativement à une cohorte similaire blessée par des mines antipersonnel (MAP). L'objectif de cette étude est de décrire le taux, la gravité et l'impact des AMS causées par des EEA. Méthodes: Nous avons analysé une base de données prospective de 100 victimes consécutives d'EEA alors qu'elles se trouvaient hors de leur véhicule et présentant des blessures de type 1 afin de comparer les résultats des cohortes ayant subi ou non des AMS. Résultats: Nous avons constaté que l'AMS (8 au-dessus du coude, 19 sous le coude, 1 au niveau du coude, 3 mains et 15 doigts) était beaucoup plus prévalente avec les EEA qu'avec les MAP (40 % c. 6 %, p < 0,001). De plus, l'AMS a été associée à un taux plus élevé d'amputations multiples (39 [98 %] c. 32 [53 %], p < 0,001), d'amputations bilatérales des membres inférieurs (AMI) (33 [82,5 %] c. 30 [53,3 %], p = 0,003) et de blessures au visage (8 [20 %] c. 4 [6,4 %], p = 0,044), mais non de blessures au bassin (10 [25%]), de mutilations génitopérinéales (19 [48 %]), de blessures oculaires (6 [15 %]), ou de fractures du crâne (6 [15 %]). Le taux de létalité a été plus élevé chez les patients ayant subi une AMS que chez ceux qui n'en ont pas subi (12 [30 %] c. 7 [12 %], p = 0,022). Conclusion: L'amputation des membres supérieurs est plus prévalente avec les EEA qu'avec les MAP. L'AMS est associée à des blessures plus graves et à un risque plus grand de décès chez les victimes d'un EEA. Les blessures aux membres supérieurs ont de graves conséquences sur la réadaptation nécessaire après l'AMI, qui accompagne presque toujours l'AMS chez les victimes d'un EEA. Les blessures aux membres supérieurs devraient pouvoir être évitées grâce à de l'équipement de protection individuelle novateur conçu pour protéger le coude fléchi.

The future of resuscitative endovascular balloon occlusion in combat operations.

Damage control resuscitation and early thoracotomy have been used to increase survival after severe injury in combat. There has been a renewed interest in resuscitative endovascular balloon occlusion of the aorta (REBOA) in both civilian and military medical practices. REBOA may result in visceral and limb ischaemia that could be harmful if use of REBOA is premature or prolonged. The purpose of this paper is to align our experience of combat injuries with the known capability of REBOA to suggest an implementation strategy for the use of REBOA in combat care. It may replace the resuscitative effect of thoracotomy; can provide haemostasis of non-compressible torso injuries such as the junctional and pelvic haemorrhage caused by improvised explosive devices. However, prehospital use of REBOA must be in the context of an overall surgical plan and should be restricted to deployment in the distal aorta. Although REBOA is technically easier than a thoracotomy, it requires operator training and skill to add to the beneficial effect of damage control resuscitation and surgery.

Management of Rib Fractures in the Combat Environment.

Rib fractures in combat casualties are an under-appreciated injury, and their treatment may become more common as more patients survive because of modern body armor and point-ofinjury care. The combat environment has challenges such as equipment availability and sterility. A simple and thoughtful rib fracture treatment algorithm may be useful to reduce the morbidity and mortality of rib fractures in the combat environment. Intravenous lidocaine infusions for patients with traumatic rib fractures may have important combat applications. We propose an algorithm for the management of combat casualties with traumatic rib fractures.

Pharmacotherapy for the prevention of chronic pain after surgery in adults.

BACKGROUND: Chronic pain can often occur after surgery, substantially impairing patients' health and quality of life. It is caused by complex mechanisms that are not yet well understood. The predictable nature of most surgical procedures has allowed for the conduct of randomized controlled trials of pharmacological interventions aimed at preventing chronic postsurgical pain. OBJECTIVES: The primary objective was to evaluate the efficacy of systemic drugs for the prevention of chronic pain after surgery by examining the proportion of patients reporting pain three months or more after surgery. The secondary objective was to evaluate the safety of drugs administered for the prevention of chronic pain after surgery. SEARCH METHODS: We identified randomized controlled trials (RCTs) of various systemically administered drugs for the prevention of chronic pain after surgery from CENTRAL, MEDLINE, EMBASE and handsearches of other reviews and trial registries. The most recent search was performed on 17 July 2013.   SELECTION CRITERIA: Included studies were double-blind, placebo-controlled, randomized trials involving adults and evaluating one or more drugs administered systemically before, during or after surgery, or both, which measured pain three months or more after surgery. DATA COLLECTION AND ANALYSIS: Data collected from each study included the study drug name, dose, route, timing and duration of dosing; surgical procedure; proportion of patients reporting any pain three months or more after surgery, reporting at least 4/10 or moderate to severe pain three months or more after surgery; and proportion of participants dropping out of the study due to treatment-emergent adverse effects. MAIN RESULTS: We identified 40 RCTs of various pharmacological interventions including intravenous ketamine (14 RCTs), oral gabapentin (10 RCTs), oral pregabalin (5 RCTs), non-steroidal anti-inflammatories (3 RCTs), intravenous steroids (3 RCTs), oral N-methyl-D-aspartate (NMDA) blockers (3 RCTs), oral mexiletine (2 RCTs), intravenous fentanyl (1 RCT), intravenous lidocaine (1 RCT), oral venlafaxine (1 RCT) and inhaled nitrous oxide (1 RCT). Meta-analysis suggested a modest but statistically significant reduction in the incidence of chronic pain after surgery following treatment with ketamine but not gabapentin or pregabalin. Results with ketamine should be viewed with caution since most of the included trials were small (that is < 100 participants per treatment arm), which could lead to the overestimation of treatment effect. AUTHORS' CONCLUSIONS: Additional evidence from better, well designed, large-scale trials is needed in order to more rigorously evaluate pharmacological interventions for the prevention of chronic pain after surgery. Furthermore, available evidence does not support the efficacy of gabapentin, pregabalin, non-steroidal anti-inflammatories, intravenous steroids, oral NMDA blockers, oral mexiletine, intravenous fentanyl, intravenous lidocaine, oral venlafaxine or inhaled nitrous oxide for the prevention of chronic postoperative pain.

Combat Vascular Access: A Scoping Review.

Medical leadership must decide how to obtain vascular access in a combat environment. Adequate combat trauma resuscitation requires efficient vascular access. A search of the Medline and EMBASE databases was conducted to find articles on combat vascular access. The primary dataset of interest was the type of vascular access obtained. Other data reviewed included who performed the intervention and the success rate of the intervention. The search strategy produced 1,339 results, of which 24 were included in the final analysis. Intravenous (IV), intraosseous (IO), and central venous access have all been used in the prehospital combat environment. This review summarizes the available combat literature to help commanders make an evidence-based decision about their prehospital vascular access strategy.

The metabolic and lipidomic profiling of the effects of tracheal occlusion in a rabbit model of congenital diaphragmatic hernia.

PURPOSE: Fetal tracheal occlusion (TO) reverses the pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH), but its mechanism of action remains poorly understood. 'Omic' readouts capture metabolic and lipid processing function, which aid in understanding CDH and TO metabolic mechanisms. METHODS: CDH was created in fetal rabbits at 23 days, TO at 28 days and lung collection at 31 days (Term ∼32 days). Lung-body weight ratio (LBWR) and mean terminal bronchiole density (MTBD) were determined. In a cohort, left and right lungs were collected, weighed, and samples homogenized, and extracts collected for non-targeted metabolomic and lipidomic profiling via LC-MS and LC-MS/MS, respectively. RESULTS: LBWR was significantly lower in CDH while CDH + TO was similar to controls (p = 0.003). MTBD was significantly higher in CDH fetuses and restored to control and sham levels in CDH + TO (p < 0.001). CDH and CDH + TO resulted in significant differences in metabolome and lipidome profiles compared to sham controls. A significant number of altered metabolites and lipids between the controls and CDH groups and the CDH and CDH + TO fetuses were identified. Significant changes in the ubiquinone and other terpenoid-quinone biosynthesis pathway and the tyrosine metabolism pathway were observed in CDH + TO. CONCLUSION: CDH + TO reverses pulmonary hypoplasia in the CDH rabbit, in association with a specific metabolic and lipid signature. A synergistic untargeted 'omics' approach provides a global signature for CDH and CDH + TO, highlighting cellular mechanisms among lipids and other metabolites, enabling comprehensive network analysis to identify critical metabolic drivers in disease pathology and recovery. TYPE OF STUDY: Basic Science, Prospective. LEVEL OF EVIDENCE: II.

Polymorphism in the protease-activated receptor-4 gene region associates with platelet activation and perioperative myocardial injury.

Protease-activated receptors (PAR)-1 and -4 are the principal receptors for thrombin-mediated platelet activation. Functional genetic variation has been described in the human PAR1 gene, but not in the PAR4 gene (F2RL3). We sought to identify variants in and around F2RL3 and to determine their association with perioperative myocardial injury (PMI) after coronary artery bypass graft surgery. We further explored possible mechanisms for F2RL3 single nucleotide polymorphism (SNP) associations with PMI including altered receptor expression and platelet activation. Twenty-three SNPs in the F2RL3 gene region were genotyped in two phases in 934 Caucasian subjects. Platelets from 43 subjects (23 major allele, 20 risk allele) homozygous for rs773857 (SNP with the strongest association with PMI) underwent flow cytometry to assess PAR4 receptor number and response to activation by a specific PAR4 activating peptide (AYPGKF) measured by von Willebrand factor (vWf) binding and P-selectin release and PAC-1 binding. We identified a novel association of SNP rs773857 with PMI (OR = 2.4, P = 0.004). rs773857 risk allele homozygotes have significantly increased platelet counts and platelets showed a significant increase in P-selectin release after activation (P = 0.004). We conclude that rs773857 risk allele homozygotes are associated with risk for increased platelet count and hyperactivity.

Systematic and scoping reviews: A comparison and overview.

In this article, we compare and contrast methods of reviewing, summarizing, and synthesizing the literature, including systematic reviews, scoping reviews, and narrative reviews. Review articles are essential to help investigators wade through the plethora of exponentially growing medical literature. In the era of evidence-based medicine, a systematic approach is required. A systematic review is a formalized method to address a specific clinical question by analyzing the breadth of published literature while minimizing bias. Systematic reviews are designed to answer narrow clinical questions in the PICO (population, intervention, comparison, and outcome) format. Alternatively, scoping reviews use a similar systematic approach to a literature search in order to determine the breadth and depth of knowledge on a topic; to clarify definitions, concepts, and themes; or sometimes as a precursor to a systematic review or hypothesis generator to guide future research. However, scoping reviews are less constrained by a priori decisions about which interventions, controls, and outcomes may be of interest. Traditional narrative reviews still have a role in informing practice and guiding research, particularly when there is a paucity of high-quality evidence on a topic.

Managing junctional haemorrhage in the combat environment.

Tactical combat casualty care and the application of extremity tourniquets have saved lives in combat. In the modern combat environment junctional injuries are common and difficult to treat. Recently, junctional tourniquets have emerged as a potential solution to this problem. Junctional tourniquets can be used as an adjunct to persistent haemorrhage despite application of conventional tourniquets or in the persistently hypotensive casualty. Surgeons must have an approach to receiving patients with junctional tourniquets in place in the operating room. The algorithms presented allow for an evidence-based and command-driven implantation of junctional tourniquets as part of tactical combat casualty care.

The effects of tracheal occlusion on Wnt signaling in a rabbit model of congenital diaphragmatic hernia.

PURPOSE: Tracheal occlusion (TO) reverses pulmonary hypoplasia (PH) in congenital diaphragmatic hernia (CDH), but its mechanism of action remains poorly understood. Wnt signaling plays a critical role in lung development, but few studies exist. The purpose of our study was to a) confirm that our CDH rabbit model produced PH which was reversed by TO and b) determine the effects of CDH +/- TO on Wnt signaling. METHODS: CDH was created in fetal rabbits at 23 days, TO at 28 days, and lung collection at 31 days. Lung body weight ratio (LBWR) and mean terminal bronchiole density (MTBD) were determined. mRNA and miRNA expression was determined in the left lower lobe using RT-qPCR. RESULTS: Fifteen CDH, 15 CDH + TO, 6 sham CDH, and 15 controls survived and were included in the study. LBWR was low in CDH, while CDH + TO was similar to controls (p = 0.003). MTBD was higher in CDH fetuses and restored to control levels in CDH + TO (p < 0.001). Reference genes TOP1, SDHA, and ACTB were consistently expressed within and between treatment groups. miR-33 and MKI67 were increased, and Lgl1 was decreased in CDH + TO. CONCLUSION: TO reversed pulmonary hypoplasia and stimulated early Wnt signaling in CDH fetal rabbits. TYPE OF STUDY: Basic science, prospective. LEVEL OF EVIDENCE: II.

Early coagulopathy and metabolic acidosis predict transfusion of packed red blood cells in pediatric trauma patients.

BACKGROUND: Severely injured pediatric trauma patients often present to hospital with early coagulopathy and metabolic acidosis. These derangements are associated with poor outcomes, but it is unclear to what degree they predict transfusion of packed red blood cells (pRBC). METHODS: We retrospectively identified pediatric trauma patients from a level 1 trauma center from 2006 to 2013. Inclusion criteria were age less than 18years, Injury Severity Score greater than 12, and pRBC transfusion within 24h of admission. RESULTS: We identified 96 pediatric trauma patients who underwent pRBC transfusion within 24h of presentation to hospital. On admission, 43% of these patients had one or more signs of coagulopathy, and 81% had metabolic acidosis. Size of pRBC transfusion in the first 24h ranged from 3 to 177mL/kg (mean 29mL/kg), and nineteen patients (20%) underwent massive transfusion (>40ml/kg in 24h). Univariate analysis indicated that size of pRBC transfusion was associated with initial base excess (r=0.46), international normalized ratio (r=0.35), partial thromboplastin time (r=0.41), fibrinogen (r=0.46), and BIG score (Base deficit, INR, Glasgow Coma Scale (GCS), r=0.36). Platelet count, age, GCS, and direct versus referred presentation were not predictive. Multivariable linear regression confirmed that coagulopathy and metabolic acidosis remained predictive after adjusting for direct versus referred presentation (R(2)=0.30). CONCLUSIONS: Early coagulopathy and metabolic acidosis predict size of pRBC transfusion among pediatric trauma patients. Further research is needed to develop massive transfusion protocols and guidelines for activation.