Noncompressible Torso Hemorrhage Research Articles

The Implementation of a Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) Program at a Level 1 New England Trauma Center: Feasibility and Early Outcomes.

We evaluated the feasibility of implementing a Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) program at our urban level 1 trauma center and evaluated early outcomes. A multidisciplinary committee including physicians (trauma surgery, emergency medicine, vascular surgery, and interventional radiology) and nurses created clinical practice guidelines for the placement of REBOA at our institution. All trauma surgeons and critical care board certified emergency medicine physicians were trained in placement and nurses received management training. A formal review process was implemented to identify areas for improvement. Finally, we instituted refresher training to maintain REBOA competency. Trauma patients with noncompressible torso hemorrhage from blunt or penetrating injuries who were partial or nonresponders to blood product resuscitation were included. Pregnant patients, children, or patients with significant hemothorax or suspected aortic or cardiac injury were excluded. Over seven months, eight catheters were successfully placed, all on the first attempt, including six in Zone 3 and two in Zone 1. All Zone 3 catheters were placed for pelvic fracture-related bleeding which were subsequently embolized. The Zone 1 catheters were placed immediately preoperatively for intraabdominal bleeding. Upon committee review, one critique was made regarding zone selection. One patient developed an arteriovenous fistula after placement which resolved without intervention. There were no other complications and all patients survived to discharge. An REBOA program is feasible and safe following a comprehensive multidisciplinary effort. The efforts described here can be utilized by similar trauma programs for adaptation of this endovascular approach to bleeding control.

Ultrasound Localization of Resuscitative Endovascular Balloon Occlusion of the Aorta in a Human Cadaver Model.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a method of gaining proximal control of noncompressible torso hemorrhage (NCTH). Catheter placement is traditionally confirmed with fluoroscopy, but few studies have evaluated whether ultrasound (US) can be used. Using a pressurized human cadaver model, a certified REBOA placer was shown one of four randomized cards that instructed them to place the REBOA either correctly or incorrectly in Zone 1 (the distal thoracic aorta extending from the celiac artery to the left subclavian artery) or Zone 3 (in the distal abdominal aorta, from the aortic bifurcation to the lowest renal artery). Once the REBOA was placed, 10 US-trained locators were asked to confirm balloon placement via US. The participants were given 3 minutes to determine whether the catheter had been correctly placed, repeating this 20 times on two cadavers. Overall, US exhibited an average sensitivity of 83%, specificity of 76%, and accuracy of 80%. For Zone 1, US showed a sensitivity of 78% and specificity of 83%, and for Zone 3, a sensitivity of 88% and specificity of 76%. In addition, US exhibited a likelihood positive ratio (LR+) of 3.73 and a likelihood negative ratio (LR-) of 0.22 for either position, with similar numbers for Zone 1 (+4.57, -0.26) and Zone 3 (+3.16, -0.16). Ultrasound could prove to be a useful tool for confirming placement of a REBOA catheter, especially in austere environments.

Brazilian guidelines on diagnosis and management of traumatic vascular injuries.

Trauma is a leading cause of death, permanent disability, and health care cost worldwide. The young and economically active are the most affected population. Exsanguination due to noncompressible torso hemorrhage is one of the most frequent causes of early death, posing a significant challenge to trauma and vascular surgeons. The possibility of limb loss due to vascular injuries must also be considered. In recent decades, the approach to vascular injuries has been significantly modified. Angiotomography has become the standard method for diagnosis, endovascular techniques are currently incorporated in treatment, and damage control, such as temporary shunts, is now the preferred approach for the patients sustaining physiological derangement. Despite the importance of this topic, few papers in the Brazilian literature have offered guidelines on vascular trauma. The Brazilian Society of Angiology and Vascular Surgery has developed Projetos Diretrizes (Guideline Projects), which includes this publication on vascular trauma. Since treating trauma patients is a multidisciplinary effort, the Brazilian Trauma Society (SBAIT) was invited to participate in this project. Members of both societies reviewed the literature on vascular trauma management and together wrote these guidelines on vascular injuries of neck, thorax, abdomen, and extremities.

43: GJA1-20K REDUCES RESUSCITATION REQUIREMENTS AND RENAL INJURY POST-REBOA ISCHEMIA-REPERFUSION INJURY

Introduction: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a promising treatment for non-compressible torso hemorrhage (NCTH). However, REBOA complications, specifically ischemia-reperfusion injury, significantly limit its therapeutic benefits and broad acceptance. GJA1-20k is a stress response protein that protects mitochondrial function. Given the central role of deranged cellular metabolism after shock, we hypothesized that GJA1-20k would mitigate REBOA-associated ischemia-reperfusion injury as shown by lowering serum lactate concentrations in a pig model of hemorrhagic shock and REBOA. Methods: Twelve Yorkshire pigs were anesthetized and subjected to hemorrhagic shock by removing 25% of the estimated blood volume, followed by 45 minutes of complete supra-coeliac REBOA. Twenty-five minutes into the occlusion period, animals received a 1-hr intravenous infusion of 0.9% saline (placebo) or GJA1-20k (0.01 mg/kg) and were transfused with autologous blood. After the balloon catheter was deflated and removed, pigs received critical care and algorithmic resuscitation with IV fluids and norepinephrine to maintain a mean arterial pressure greater than 65 mmHg. Results: While there was no difference in serum lactate concentration at the end of the study (Control: 5.6 [3.0-6.7] mmol/L, GJA1-20k: 3.5 [3.0-3.8] mmol/L, p=0.1), the GJA1-20k treatment group had a reduction in resuscitation fluid requirements (Control: 62.5 [50-90] mL/kg, GKA1-20k: 22.5 [0-50] mL/kg, p=0.03). Importantly, with GJA1-20k treatment, 2 animals required no fluid boluses, and another only required 10 mL/kg of IV fluids. GJA1-20k group was showed a reduction in final serum creatinine concentration (Control: 2.8 +/-0.3 mg/dL, GJA1-20k: 2.4 +/- 0.3 mg/dL, p=0.03). Conclusions: While there was no significant difference in serum lactate concentration between groups, GJA1-20k significantly reduced fluid resuscitation requirements and renal injury following REBOA in a pig model of hemorrhagic shock. Mitochondrial protection is a potential target for mitigating REBOA-associated ischemia-reperfusion injury after hemorrhagic shock.

Do we need pre-hospital resuscitative endovascular balloon occlusion of the aorta (REBOA) in the civilian helicopter emergency medical services (HEMS)?

Pre-hospital resuscitative endovascular balloon occlusion of the aorta (REBOA) can be a life-saving procedure for patients with non-compressible torso hemorrhage. We aimed to evaluate the potential eligibility for REBOA in trauma patients of a civilian helicopter emergency medical service (HEMS) using a stepwise approach. A retrospective analysis using the electronic database (HEMSDER) of "DRF Luftrettung" HEMS covering the period from January 2015 to June 2021 was performed. Trauma patients aged ≥ 16years and with a National Advisory Committee for Aeronautics (NACA) score of ≥ 4 were assessed for potential REBOA eligibility using two different decision trees based on assumed severe bleeding due to injuries of the abdomen, pelvis, and/or lower extremities and different vital signs on the scene and at hospital handover. Non-parametric statistical methods were used for comparison. A total of 22.426 patients met the inclusion criteria for data analysis. Of these, 0.15-2.24% were possible candidates for pre-hospital REBOA. No significant differences between groups on scene and at hospital handover regarding demographics, assumed injuries, and pre-hospital interventions were found. In the on-scene group, 21.1% of the patients remained unstable even at hospital handover despite pre-hospital care. In the handover group, 42.8% of the patients seemed initially stable but then deteriorated during the pre-hospital course. The number of potential pre-hospital REBOA in severely injured patients with a NACA score of ≥ 4 is < 3% or can be even < 1% if more strict criteria are used. There are some patients who may benefit from pre-hospital REBOA as a life-saving procedure. Further research on earlier diagnosis of life-threatening bleeding and proper indications of REBOA in trauma patients is needed.

Systematic review to evaluate algorithms for REBOA use in trauma and identify a consensus for patient selection

BackgroundPatient selection for resuscitative endovascular balloon occlusion of the aorta (REBOA) has evolved during the last decade. A recent multicenter collaboration to implement the newest generation REBOA balloon catheter identified...

A comparison of mortality and indicators of treatment success of resuscitative endovascular balloon occlusion of aorta (REBOA): a systematic review and meta-analysis.

Emergency resuscitative thoracotomy (RT) is a recognised method of controlling non-compressible torso haemorrhage (NCTH) often in adjunct to emergency surgery. Recently, there is much debate regarding resuscitative endovascular balloon occlusion of aorta (REBOA) on its role in civilian trauma cases in controlling NCTH. This study aims to provide an updated review on in-hospital mortality rates in patients who underwent REBOA versus RT and standard care without REBOA (non-REBOA) and to identify the potential indicators of REBOA survival. Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used to perform the study. All adult trauma cases were included, while pre-hospital, military and non-English studies were excluded. A literature search was done on studies from 01 January 2005 to 30 June 2020 using EMBASE, MEDLINE and COCHRANE databases. Risk of bias was assessed using the Methodological Index for Non-Randomised Studies (MINORS) tool. Meta-analysis was conducted using a random effects model and the DerSimonian and Laird estimation method. A significance level of p < 0.05 was used. Twenty-five studies were included in this study. The odds of in-hospital mortality of patients who underwent REBOA compared to RT was 0.18 (p < 0.01, 0.12-0.26). The odds of in-hospital survival of patients who underwent REBOA compared to non-REBOA was 1.28 (p = 0.62, 0.46-3.53). There was a significant difference found between survivors and non-survivors in terms of their pre-REBOA systolic blood pressure (SBP) (19.26mmHg, p < 0.01), post-REBOA SBP (20.73mmHg, p < 0.01), duration of aortic occlusion (- 40.57min, p < 0.01) and injury severity score (- 8.50, p < 0.01). REBOA has a potential for wider application in civilian settings, with our study demonstrating lower in-hospital mortality compared to RT. Prospective multi-centre studies are needed for further evaluation of the indications and feasibility of REBOA.Level of Evidence + Study Type: Level IV. Systematic review with meta-analysis. The online version contains supplementary material available at 10.1007/s12055-022-01413-3.

Abstract 190: Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) After Traumatic Brain Injury

Aim: The effects of resuscitative endovascular balloon occlusion of the aorta (REBOA) on progression of traumatic brain injury (TBI) are unclear. Swine models have shown conflicting results, and human data is lacking. Two hypotheses largely prevail: increased mean arterial pressure caused by REBOA may improve cerebral perfusion, or conversely, cause cerebral edema due to elevated blood and intracranial pressure. This study aims to compare outcomes in patients with TBI treated with and without REBOA. Methods: A retrospective analysis compared blunt trauma patients with TBI treated with REBOA to those treated without. REBOA patients were selected from the Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery (AORTA) registry, and non-REBOA patients were selected from an institutional trauma registry. Patients with SBP &gt; 0mmHg at admission and at initiation of aortic occlusion were included. Patients requiring CPR at ED were excluded. Propensity score matching was performed using age, gender, ISS, AIS-Head, and admission SBP. Results: After matching, 106 REBOA patients and 106 non-REBOA patients remained for analysis. REBOA patients had significantly higher ISS, but there was no difference in AIS-Head, pre-hospital or ED GCS, ED SBP, or in-hospital mortality (Table). Despite longer hospital stays for REBOA patients, there was no difference in ICU length of stay or rate of discharge home between groups. Conclusion: REBOA was used in more severely injured patients, but was not associated with higher mortality rate. Despite longer hospital stays for REBOA patients, discharge GCS and rate of discharge home, both favorable patient-centered outcomes, were similar between groups. REBOA use should be considered for use in patients with non-compressible torso hemorrhage and concomitant TBI, as it here it did not increase mortality, and outcomes upon discharge are similar to patients treated without REBOA.

REBOA: Expanding Applications From Traumatic Hemorrhage to Obstetrics and Cardiopulmonary Resuscitation, From the AJR Special Series on Emergency Radiology.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged over the past decade as a technique to control life-threatening hemorrhage and treat hemorrhagic shock, being increasingly used to treat noncompressible traumatic torso hemorrhage. Reports during this time also support the use of a REBOA device for an expanding range of indications including nontraumatic abdominal hemorrhage, postpartum hemorrhage, placenta accreta spectrum (PAS) disorder, and cardiopulmonary resuscitation (CPR). The strongest available evidence supports REBOA as a lifesaving adjunct to definitive surgical management in trauma and as a method to help avoid hysterectomy in select patients with postpartum hemorrhage or PAS disorder. In comparison with initial descriptions of complete REBOA inflation, techniques for partial REBOA inflation have been introduced to achieve hemodynamic stability while minimizing adverse events relating to reperfusion injuries. Fluoroscopy-free REBOA has been described in various settings, including trauma, obstetrics, and out-of-hospital cardiac arrest. As the use of REBOA expands outside the trauma setting and into nontraumatic abdominal hemorrhage, obstetrics, and CPR, it is imperative for radiologists to become familiar with this technology, its proper placement, and its potential adverse sequelae.

Resuscitative Endovascular Balloon Occlusion of the Aorta for Traumatic Cardiopulmonary Arrest in the Emergency Department: The First Case With Successful Return of Spontaneous Circulation in Taiwan.

Exsanguinating torso hemorrhage is a leading cause of death in trauma patients. Bleeding leads to hypothermia, acidosis, and coagulopathy, the so-called "lethal triad," and creates a vicious cycle. Therefore, bleeding control tops the priority list in the management of trauma patients. Placement of resuscitative endovascular balloon occlusion of the aorta (REBOA) in patients with traumatic non-compressible torso hemorrhage is a developing technique in the emergency departments (EDs) in Taiwan, and it is a possible solution for abdominal and pelvic trauma patients with hemodynamic instability. It not only temporarily controls bleeding below the inflation site but also increases cerebral and coronary circulation. It can create a bridge for definitive care such as an operation or an embolization, possibly preventing death. Compared to thoracotomy followed by an aortic cross clamp, REBOA is a less invasive and possibly, a more efficient way to control the hemorrhage and may lead to better overall survival. The use of REBOA has been proven to be associated with improved survival-to-discharge in severely injured trauma patients. We report a case of out-of-hospital cardiac arrest caused by penetrating injury wherein return of spontaneous circulation was successfully achieved after 39-minute cardiopulmonary resuscitation and REBOA placement in the ED. The REBOA balloon was deflated after bleeding was stopped during the laparotomy operation. The patient was then transferred to the intensive care unit for postoperative care. Unfortunately, the patient passed away approximately 12 hours after the surgery.

Thermoreversible Reverse-Phase-Shift Foam for Treatment of Noncompressible Torso Hemorrhage, a Safety Trial in a Porcine Model.

Noncompressible torso hemorrhage is the leading cause of exsanguination on the battlefield. A self-expanding, intraperitoneal deployed, thermoreversible foam has been developed that can be easily administered by a medic in austere settings to temporarily tamponade noncompressible torso hemorrhage. The purpose of this study was to assess the long-term safety and physical characteristics of using Fast Onset Abdominal Management (FOAM; Critical Innovations LLC) in swine. Yorkshire swine (40-60 kg) were sedated, intubated, and placed on ventilatory support. An external jugular catheter was placed for sampling of blood. Continuous heart rate, temperature, saturation of peripheral oxygen, end-tidal carbon dioxide, and peak airway pressures were monitored for a 4-hour period after intervention (i.e., FOAM agent injection or a sham introducer without agent delivery). The FOAM agent was injected to obtain an intra-abdominal pressure of 60 mmHg for at least 10 minutes. After 4 hours, the animals were removed from ventilatory support and returned to their housing for a period of 7-14 days. Group size analysis was not performed, as this was a descriptive safety study. Blood samples were obtained at baseline and at 1-hour post-intervention and then on days 1, 3, 7, and 14. Euthanasia, necropsy, and harvesting of samples for histologic analysis (from kidneys, terminal ilium, liver, pancreas, stomach, spleen, and lungs) were performed upon expiration. Histologic scoring for evidence of ischemia, necrosis, and abdominal compartment sequela was blinded and reported by semi-quantitative scale (range 0-4; 0 = no change, 1 = minimal, 2 = mild, 3 = moderate, and 4 = marked). Oregon Health & Science University's Institutional Animal Care and Use Committee, as well as the U.S. Army Animal Care and Use Review Office, approved this protocol before the initiation of experiments (respectively, protocol numbers IP00003591 and MT180006.e002). Five animals met a priori inclusion criteria, and all of these survived to their scheduled endpoints. Two animals received sham injections of the FOAM agent (one euthanized on day 7 and one on day 14), and three animals received FOAM agent injections (one euthanized on day 7 and two on day 14). A transitory increase in creatinine and lactate was detected during the first day in the FOAM injected swine but resolved by day 3. No FOAM agent was observed in the peritoneal cavity upon necropsy at day 7 or 14. Histologic data revealed no clinically relevant differences in any organ system between intervention and control animals upon sacrifice at day 7 or 14. This study describes the characteristics, survival, and histological analysis of using FOAM in a porcine model. In our study, FOAM reached the desired intra-abdominal pressure endpoint while not significantly altering basic hematologic parameters, except for transient elevations of creatinine and lactate on day 1. Furthermore, there was no clinical or histological relevant evidence of ischemia, necrosis, or intra-abdominal compartment syndrome. These results provide strong support for the safety of the FOAM device and will support the design of further regulatory studies in swine and humans.

Perspectives on the management of non-compressible torso hemorrhage: A narrative review

LAY SUMMARY Hemorrhage is one of the leading causes of death after trauma. A significant proportion of these fatalities could be prevented with appropriate bleeding control. This is more easily achieved with direct pressure in compressible areas such as the extremities or major joints. However, bleeding in the chest, abdomen, or pelvis cannot be as easily controlled without advanced procedures that are only available in hospitals. This article describes several technologies to control bleeding in the chest, abdomen, and pelvis that are potentially applicable in combat and pre-hospital settings. However, a review of existing studies quickly shows that convincing clinical evidence is lacking to support most pre-existing technologies, and the majority of studies are in the investigational stage. A universal, effective, and life-saving solution has not yet been identified. Accordingly, research in this area should continue to focus on both refining existing technologies and developing new approaches.

Tandem use of gastroesophageal resuscitative occlusion of the aorta followed by resuscitative endovascular balloon occlusion of the aorta in a lethal liver laceration model.

Gastroesophageal resuscitative occlusion of the aorta (GROA) has been shown effective in creating zone II aortic occlusion capable of temporarily improving survival in animal models of lethal noncompressible torso hemorrhage. In this study, tandem application of GROA transitioning to resuscitative endovascular balloon occlusion of the aorta (REBOA) is explored to demonstrate feasibility as a potential point-of-injury bridge to more advanced care, using a swine model of lethal abdominal hemorrhage. Swine (n = 19) were anesthetized, instrumented, and subjected to a combination of controlled and uncontrolled hemorrhage from a grade-V liver laceration. Animals were designated as intervention (n = 9; GROA to REBOA) or control (n = 10), for 60 minutes. Following intervention, devices were deactivated, and animals received blood and crystalloid resuscitation. Animals were monitored for 4 hours. Injury resulted in onset of class IV shock in all animals with a mean arterial pressure (SD) of 24.5 (4.11) mm Hg at the start of intervention. Nine of 10 controls died during the intervention period with a median (interquartile) survival time of 8.5 (9.25) minutes. All animals receiving the intervention survived both the 60-minute intervention period demonstrating a significant survival improvement ( p = 0.0007). Transition from GROA to REBOA was successful in all animals with a transition time ranging from 30 to 90 seconds. Mean arterial pressure significantly improved in animals receiving GROA to REBOA for the duration of intervention, regardless of the method of aortic occlusion, with a range of 70.9 (16.04) mm Hg to 101.1 (15.3) mm Hg. Additional hemodynamics, metrics of shock, and oxygenation remained stable during intervention. Less invasive technologies such as GROA may present an opportunity to control noncompressible torso hemorrhage more rapidly, with a subsequent transition to more advanced care such as REBOA.

A Magnetic Sensor-equipped Retrievable Aortic Rescue Stent Graft for Noncompressible Torso Hemorrhage

Noncompressible torso hemorrhage (NCTH) remains a high mortality injury, and it is often impossible to mobilize resources before exsanguination. We have reported on a retrievable stent graft for damage control and human morphometric analysis; yet, the gold standard of fluoroscopy for device placement is impractical for the austere environment. We hypothesized that a magnetic sensor could be used to position stent grafts relative to an external magnet placed on an anatomic landmark in the austere environment when fluoroscopy is not immediately available.

Resuscitative endovascular balloon occlusion of the aorta in Canada: a context-specific position paper from the Canadian Collaborative for Urgent Care Surgery (CANUCS).

Summary Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a well-described intervention for noncompressible torso hemorrhage. Several Canadian centres have included REBOA in their hemorrhagic shock protocols. However, REBOA has known complications and equipoise regarding its use persists. The Canadian Collaborative on Urgent Care Surgery (CANUCS) comprises surgeons who provide acute trauma care and leadership in Canada, with experience in REBOA implementation, use, education and research. Our goal is to provide evidence- and experience-based recommendations regarding institutional implementation of a REBOA program, including multidisciplinary educational programs, attention to device and care pathway logistics, and a robust quality assurance program. This will allow Canadian trauma centres to maximize patient benefits and minimize risks of this potentially life-saving technology.

Resuscitative endovascular balloon occlusion of the aorta associated with improved survival in hemorrhagic shock.

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is controversial as a hemorrhage control adjunct due to lack of data with a suitable control group. We aimed to determine outcomes of trauma patients in shock undergoing REBOA versus no-REBOA. This single-center, retrospective, matched cohort study analyzed patients ≥16 years in hemorrhagic shock without cardiac arrest (2000-2019). REBOA (R; 2015-2019) patients were propensity matched 2:1 to historic (H; 2000-2012) and contemporary (C; 2013-2019) groups. In-hospital mortality and 30-day survival were analyzed using chi-squared and log rank testing, respectively. A total of 102,481 patients were included (R = 57, C = 88,545, H = 13,879). Propensity scores were assigned using age, race, mechanism, lowest systolic blood pressure, lowest Glasgow Coma Score (GCS), and body region Abbreviated Injury Scale scores to generate matched groups (R = 57, C = 114, H = 114). In-hospital mortality was significantly lower in the REBOA group (19.3%) compared to the contemporary (35.1%; p = 0.024) and historic (44.7%; p = 0.001) groups. 30-day survival was significantly higher in the REBOA versus no-REBOA groups. In a high-volume center where its use is part of a coordinated hemorrhage control strategy, REBOA is associated with improved survival in patients with noncompressible torso hemorrhage.

The Role of Prehospital REBOA for Hemorrhage Control in Civilian and Military Austere Settings: A Systematic Review

Despite the success of prehospital resuscitative endovascular balloon occlusion of the aorta (REBOA) in combat and civilian settings, the prevalence of complications and the lack of conclusive evidence has led to uncertainty and controversy. Therefore, this systematic review aimed to evaluate the role of prehospital REBOA for hemorrhage control in trauma populations. We systematically searched Cochrane, Ovid MEDLINE, EMBASE and Google Scholar for all relevant studies that investigated the efficacy of prehospital REBOA on trauma patients with massive hemorrhage. Primary outcome was evaluated by blood pressure elevation and secondary outcome was measured by 30-day mortality and complications. Our search identified 546 studies, but only six studies met the inclusion and exclusion criteria. Included studies were low to moderate quality due to limitations within the studies. However, all of the studies reported significant elevation of blood pressure and survival, demonstrating the potential benefits of REBOA. For example, the 30-day mortality rate reduced significantly after REBOA, but studies lacked long-term outcome assessments across the continuum of care. Due to the heterogeneity of the results, a meta-analysis was not possible. We conclude that prehospital REBOA is a feasible and effective resuscitative adjunct for shock patients with lethal non-compressible torso hemorrhage. However, due to the unclear causes of complications and the lack of high quality and homogeneous data, the effects of prehospital REBOA were not truly reflected and comparison between groups was not feasible. Thus, further high-quality studies are required to attest the causality between prehospital REBOA and outcomes.

Modulating Nanoparticle Size to Understand Factors Affecting Hemostatic Efficacy and Maximize Survival in a Lethal Inferior Vena Cava Injury Model.

Intravenous nanoparticle hemostats offer a potentially attractive approach to promote hemostasis, in particular for inaccessible wounds such as noncompressible torso hemorrhage (NCTH). In this work, particle size was tuned over a range of <100-500 nm, and its effect on nanoparticle-platelet interactions was systematically assessed using in vitro and in vivo experiments. Smaller particles bound a larger percentage of platelets per mass of particle delivered, while larger particles resulted in higher particle accumulation on a surface of platelets and collagen. Intermediate particles led to the greatest platelet content in platelet-nanoparticle aggregates, indicating that they may be able to recruit more platelets to the wound. In biodistribution studies, smaller and intermediate nanoparticles exhibited longer circulation lifetimes, while larger nanoparticles resulted in higher pulmonary accumulation. The particles were then challenged in a 2 h lethal inferior vena cava (IVC) puncture model, where intermediate nanoparticles significantly increased both survival and injury-specific targeting relative to saline and unfunctionalized particle controls. An increase in survival in the second hour was likewise observed in the smaller nanoparticles relative to saline controls, though no significant increase in survival was observed in the larger nanoparticle size. In conjunction with prior in vitro and in vivo experiments, these results suggest that platelet content in aggregates and extended nanoparticle circulation lifetimes are instrumental to enhancing hemostasis. Ultimately, this study elucidates the role of particle size in platelet-particle interactions, which can be a useful tool for engineering the performance of particulate hemostats and improving the design of these materials.

Impact of time to surgery on mortality in hypotensive patients with noncompressible torso hemorrhage: An AAST multicenter, prospective study.

Death from noncompressible torso hemorrhage (NCTH) may be preventable with improved prehospital care and shorter in-hospital times to hemorrhage control. We hypothesized that shorter times to surgical intervention for hemorrhage control would decrease mortality in hypotensive patients with NCTH. This was an AAST-sponsored multicenter, prospective analysis of hypotensive patients aged 15+ years who presented with NCTH from May 2018 to December 2020. Hypotension was defined as an initial systolic blood pressure (SBP) ≤ 90 mm Hg. Primary outcomes of interest were time to surgical intervention and in-hospital mortality. There were 242 hypotensive patients, of which 48 died (19.8%). Nonsurvivors had higher mean age (47.3 vs. 38.8; p = 0.02), higher mean New Injury Severity Score (38 vs. 29; p < 0.001), lower admit systolic blood pressure (68 vs. 79 mm Hg; p < 0.01), higher incidence of vascular injury (41.7% vs. 21.1%; p = 0.02), and shorter median (interquartile range, 25-75) time from injury to operating room start (74 minutes [48-98 minutes] vs. 88 minutes [61-128 minutes]; p = 0.03) than did survivors. Multivariable Cox regression showed shorter time from emergency department arrival to operating room start was not associated with improved survival (p = 0.04). Patients who died arrived to a trauma center in a similar time frame as did survivors but presented in greater physiological distress and had significantly shorter times to surgical hemorrhage intervention than did survivors. This suggests that even expediting a critically ill patient through the current trauma system is not sufficient time to save lives from NCTH. Civilian prehospital advance resuscitative care starting from the patient first contact needs special consideration. Prognostic/Epidemiologic, Level III.

The anchor point algorithm: A morphometric analysis of anatomic landmarks to guide placement of temporary aortic Rescue stent grafts for noncompressible torso hemorrhage.

Noncompressible hemorrhage remains a high-mortality injury, which requires rapid damage control within minutes to avoid exsanguination. Retrievable stent grafts offer perfusion preserving hemorrhage damage control, and yet algorithms for device selection and positioning are lacking for an anatomically diverse human population. We hypothesized that easily acquired external measurements could be used to rapidly triage patients to receive one of several presized stents and that these metrics may further predict a single target on the aorta by which to optimize both mesenteric perfusion and aortic hemorrhage control. Metrics were acquired from computed tomography imaging of 203 male and female patients aged 18 to 50 years. Algorithms for metric based triage and stent sizing were examined against the cohort for effectiveness. Linear regression was used to predict a single target on the aorta for alignment of a multitiered stent. Next, the relationship of the anchor point to the palpable xiphoid was determined. Clavicle to pubis measurements correlated with aortic length and was used to triage patients to one of three stent grafts. Stents for each triage group were sized to achieve >75% coverage of aortic Zones 1 and 3 in most patients while preserving carotid and visceral perfusion. A metric/sex-based equation that predicts the location of the superior mesenteric artery relative to the palpable xiphoid was derived. By alignment of a single point on the stent with this target, known as the anchor point, the remainder of the stent can be rapidly deployed while minimizing coverage of critical branches. When applied back to the cohort, only 10.4% had potential serious branch coverage events predicted. Simple anatomic metrics offer rapid triage in this study population to one of three presized stent grafts and predict the location of key vascular branches. Confirmatory human trials will be essential to demonstrate safety and effectiveness of this approach. Prognostic/Epidemiological; Level IV.