Complete and Partial Resuscitative Endovascular Balloon Occlusion of the Aorta for Hemorrhagic Shock.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) devices grew out of a military-civilian partnership to develop new capabilities for hemorrhage control. With the advent of purpose-built devices, REBOA has become increasingly common in civilian trauma and acute care settings. Currently available REBOA catheters were designed as complete aortic occlusion devices. However, the therapeutic window for complete aortic occlusion is time-limited due to ischemia-reperfusion injury. The partial procedure allows blood flow past the level of occlusion while maintaining targeted proximal pressure, which has been shown to reduce distal ischemia and adjunctive resuscitation requirements in preclinical studies with prolonged occlusion times as compared to traditional complete occlusion. pREBOA-PRO is the first catheter designed to enable partial and complete aortic occlusion and is currently in limited market release at seven Level I trauma centers in North America. This paper will focus on procedural considerations for REBOA, including patient selection criteria and a comparison of complete and partial aortic occlusion in a simulator, along with highlighting critical steps to improve clinical outcomes. Additionally, this paper reviews a contrast-enhanced CT scan from a trauma patient that shows distal perfusion after 2 h of partial aortic occlusion using this newly designed catheter and discusses representative results from the limited market release to highlight the profound effect of technological innovation on outcomes in vascular emergencies.

Targeted Regional Optimization in Action: Dose-dependent End-organ Ischemic Injury with Partial Aortic Occlusion in the Setting of Ongoing Liver Hemorrhage.

INTRODUCTION: Targeted regional optimization (TRO) describes partial resuscitative endovascular balloon occlusion of the aorta strategy that allows for controlled distal perfusion to balance hemostasis and tissue perfusion. This study characterized hemodynamics at specific targeted distal flow rates in a swine model of uncontrolled hemorrhage to determine if precise TRO by volume was possible. METHODS: Anesthetized swine were subjected to liver laceration and randomized into TRO at distal flows of 300 mL/min (n = 8), 500 mL/min (n = 8), or 700 mL/min (n = 8). After 90 min, the animals received damage control packing and were monitored for 6 h. Hemodynamic parameters were measured continuously, and hematology and serologic labs obtained at predetermined intervals. RESULTS: During TRO, the average percent deviation from the targeted flow was lower than 15.9% for all cohorts. Average renal flow rates were significantly different across all cohorts during TRO phase (P < 0.0001; TRO300 = 63.1 ±â€Š1.2; TRO500 = 133.70 ±â€Š1.93; TRO700 = 109.3 ±â€Š2.0), with the TRO700 cohort having less renal flow than TRO500. The TRO500 and TRO700 average renal flow rates inverted during the intensive care unit phase (P < 0.0001; TRO300 = 86.20 ±â€Š0.40; TRO500 = 148.50 ±â€Š1.45; TRO700 = 181.1 ±â€Š0.70). There was higher blood urea nitrogen, creatinine, and potassium in the TRO300 cohort at the end of the experiment, but no difference in lactate or pH between cohorts. CONCLUSION: This study demonstrated technical feasibility of TRO as a strategy to improve outcomes after prolonged periods of aortic occlusion and resuscitation in the setting of ongoing solid organ hemorrhage. A dose-dependent ischemic end-organ injury occurs beginning with partial aortic occlusion that progresses through the critical care phase, with exaggerated effect on renal function.

Targeted Regional Optimization: Increasing the Therapeutic Window for Endovascular Aortic Occlusion In Traumatic Hemorrhage.

ABSTRACT: Resuscitative endovascular balloon occlusion of the aorta (REBOA) allows for effective temporization of exsanguination from non-compressible hemorrhage (NCTH) below the diaphragm. However, the therapeutic window for aortic occlusion is time-limited given the ischemia-reperfusion injury generated. Significant effort has been put into translational research to develop new strategies to alleviate the ischemia-reperfusion injury and extend the application of endoaortic occlusion. Targeted regional optimization (TRO) is a partial REBOA strategy to augment proximal aortic and cerebral blood flow while targeting minimal threshold of distal perfusion beyond the zone of partial aortic occlusion. The objective of TRO is to reduce the degree of ischemia caused by complete aortic occlusion while providing control of distal hemorrhage. This review provides a synopsis of the concept of TRO, pre-clinical, translational experiences with TRO and early clinical outcomes. Early results from TRO strategies are promising; however, further studies are needed prior to large-scale implementation into clinical practice.

Partial Resuscitative Endovascular Balloon Occlusion of the Aorta: A Systematic Review of the Preclinical and Clinical Literature.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has become a standard adjunct for the management of life-threatening truncal hemorrhage, but the technique is limited by the sequalae of ischemia distal to occlusion. Partial REBOA addresses this limitation, and the recent Food and Drug Administration approval of a device designed to enable partial REBOA will broaden its application. We conducted a systematic review of the available animal and clinical literature on the methods, impacts, and outcomes associated with partial REBOA as a technique to enable targeted proximal perfusion and limit distal ischemic injury. We hypothesize that a systematic review of the published animal and human literature on partial REBOA will provide actionable insight for the use of partial REBOA in the context of future wider clinical implementation of this technique. METHODS: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Protocols guidelines, we conducted a search of the available literature which used partial inflation of a REBOA balloon catheter. Findings from 22 large animal studies and 14 clinical studies met inclusion criteria. RESULTS: Animal and clinical results support the benefits of partial REBOA including extending the resuscitative window extended safe occlusion time, improved survival, reduced proximal hypertension, and reduced resuscitation requirements. Clinical studies provide practical physiologic targets for partial REBOA including a period of total occlusion followed by gradual balloon deflation to achieve a target proximal pressure and/or target distal pressure. CONCLUSIONS: Partial REBOA has several benefits which have been observed in animal and clinical studies, most notably reduced ischemic insult to tissues distal to occlusion and improved outcomes compared with total occlusion. Practical clinical protocols are available for the implementation of partial REBOA in cases of life-threatening torso hemorrhage.

U.S. Military Experience From 2001 to 2010 With Extremity Fasciotomy in War Surgery.

INTRODUCTION: After trauma, compartment syndrome of the extremities is a common, disabling, and-if managed suboptimally-lethal problem. Its treatment by surgical fasciotomy continues to be useful but controversial. The purpose of this survey is to measure survival and fasciotomy in a large trauma system to characterize trends and to determine if fasciotomy is associated with improved survival. METHODS: We retrospectively surveyed data from a military trauma registry for U.S. casualties from 2001 to 2010. Casualties had extremity injury or extremity fasciotomy. We associated survival and fasciotomy. RESULTS: Of 17,166 casualties in the total study, 19% (3,313) had fasciotomy and 2.8% (481) had compartment syndrome. Annual fasciotomy rates started at 0% (2001) and rose to 26% (2010). For all casualties, the survival rate initially was high (100%) but decreased steadily until its nadir (96.4%) in 2005. Thereafter, it increased to make a V-shaped trend with reversal occurring after fielding two interventions within the trauma system specifically for casualties at risk for fasciotomy-tourniquet use and a fasciotomy education program. CONCLUSIONS: Over a decade of war, the survival rate of extremity injured casualties was associated with two trauma system interventions-tourniquet usage and a fasciotomy education program. The current example of measuring implementation of initiatives may be useful as a model for future attempted improvements in health care.

Which Improvised Tourniquet Windlasses Work Well and Which Ones Won't?

OBJECTIVE: Improvised tourniquets in first aid are recommended when no scientifically designed tourniquet is available. Windlasses for mechanical advantage can be a stick or pencil and can be used singly or multiply in tightening a tourniquet band, but currently there is an absence of empiric knowledge of how well such windlasses work. The purpose of the present study was to determine the performance of improvised tourniquets in their use by the type and number of windlasses to improve tourniquet practice. METHODS: A simulated Leg Tourniquet Trainer was used as a manikin thigh to test the effectiveness of improvised tourniquets of a band-and-windlass design. Two users made 20 tests each with 3 types of windlasses. Tests started with 1 representative of a given type (eg, 1 pencil), then continued with increasing numbers of each windlass type until the user reached 100% effectiveness as determined by cessation of simulated blood flow. Windlass types included chopsticks, pencils, and craft sticks. RESULTS: Effectiveness percentages in stopping bleeding were associated inversely with breakage percentages. Pulse stoppage percentages were associated inversely with breakage. The windlass turn numbers, time to stop bleeding, the number of windlasses, and the under-tourniquet pressure were associated inversely with breakage. The windlass type was associated with breakage; at 2 windlasses, only chopsticks were without breakage. Of those windlass types that broke, 20.7% were chopsticks, 26.1% were pencils, and 53.2% were craft sticks. CONCLUSIONS: A pair of chopsticks as an improvised tourniquet windlass worked better than pencils or craft sticks.

U.S. Military use of tourniquets from 2001 to 2010.

OBJECTIVE: This study was conducted to associate tourniquet use and survival in casualty care over a decade of war in order to provide evidence to emergency medical personnel for the implementation and efficacy of tourniquet use in a large trauma system. METHODS: This survey is a retrospective review of data extracted from a trauma registry. The decade (2001-2010) outcome trend analysis of tourniquet use in the current wars was made in order to associate tourniquet use and survival in an observational cohort design. RESULTS: Of 4,297 casualties with extremity trauma in the total study, 30% (1,272/4,297) had tourniquet use and 70% (3,025/4,297) did not. For all 4,297 casualties, the proportion of casualties with severe or critical extremity Abbreviated Injury Scales (AIS) increased during the years surveyed (p < 0.0001); the mean annual Injury Severity Score (ISS) rose from 13 to 21. Tourniquet use increased during the decade by almost tenfold from 4 to nearly 40% (p < 0.0001). Survival for casualties with isolated extremity injury varied by injury severity; the survival rate for AIS 3 (serious) was 98%, the rate for AIS 4 (severe) was 76%, and the rate for AIS 5 (critical) was 0%. Survival rates increased for casualties with injuries amenable to tourniquets but decreased for extremity injuries too proximal for tourniquets. CONCLUSIONS: Average injury severity increased during the decade of war for casualties with extremity injury. Both tourniquet use rates and casualty survival rates rose when injuries were amenable to tourniquets.

Transfusion for shock in US military war casualties with and without tourniquet use.

STUDY OBJECTIVE: We assess whether emergency tourniquet use for transfused war casualties admitted to military hospitals is associated with survival. METHODS: A retrospective review of trauma registry data was made of US casualties in Afghanistan and Iraq. Patients with major limb trauma, transfusion, and tourniquet use were compared with similar patients who did not receive tourniquet use. A propensity-matching analysis was performed by stratifying for injury type and severity by tourniquet-use status. Additionally, direct comparison without propensity matching was made between tourniquet use and no-tourniquet use groups. RESULTS: There were 720 casualties in the tourniquet use and 693 in the no-tourniquet use groups. Of the 1,413 casualties, 66% (928) also had nonextremity injury. Casualties with tourniquet use had worse signs of hemorrhagic shock (admission base deficit, admission hemoglobin, admission pulse, and transfusion units required) than those without. Survival rates were similar between the 2 groups (1% difference; 95% confidence interval -2.5% to 4.2%), but casualties who received tourniquets had worse shock and received more blood products. In propensity-matched casualties, survival rates were not different (2% difference; 95% confidence interval -6.7% to 2.7%) between the 2 groups. CONCLUSION: Tourniquet use was associated with worse shock and more transfusion requirements among hospital-admitted casualties, yet those who received tourniquets had survival rates similar to those of comparable, transfused casualties who did not receive tourniquets.

Antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model: implications for prophylaxis and treatment of combat-related wound infections.

In this study, we investigated the utility of antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model. A bioluminescent clinical isolate of multidrug-resistant A. baumannii was obtained. The susceptibility of A. baumannii to blue light (415 nm)-inactivation was compared in vitro to that of human keratinocytes. Repeated cycles of sublethal inactivation of bacterial by blue light were performed to investigate the potential resistance development of A. baumannii to blue light. A mouse model of third degree burn infected with A. baumannii was developed. A single exposure of blue light was initiated 30 minutes after bacterial inoculation to inactivate A. baumannii in mouse burns. It was found that the multidrug-resistant A. baumannii strain was significantly more susceptible than keratinocytes to blue light inactivation. Transmission electron microscopy revealed blue light-induced ultrastructural damage in A. baumannii cells. Fluorescence spectroscopy suggested that endogenous porphyrins exist in A. baumannii cells. Blue light at an exposure of 55.8 J/cm(2) significantly reduced the bacterial burden in mouse burns. No resistance development to blue light inactivation was observed in A. baumannii after 10 cycles of sublethal inactivation of bacteria. No significant DNA damage was detected in mouse skin by means of a skin TUNEL assay after a blue light exposure of 195 J/cm(2).

Citation classics in the burn literature during the past 55 years.

The objective of this study was to identify the 100 most cited, peer-reviewed burn-related articles over the past half century. Burn care presents ongoing challenges to both U.S. civilian and military healthcare personnel. Improvements in burn survival and quality of life are the result of advances in burn research. The Web of Science (including Science Citation Index) was searched for the most cited articles related to burn care, published from 1955 to the present. The most cited article was "Permanent coverage of large burn wounds with autologous cultured human epithelium," by G.G. Gallico et al, New England Journal of Medicine, 1984 (711 citations). Between the 1970s and the 1990s, there was a near doubling of the number of highly cited publications with each subsequent decade. A total of 85% of the articles were on the topics of pathophysiology (37%), wounds, tissue, or dressings (31%), or organ failure/sepsis (17%). B.A. Pruitt Jr. (2320 citations), D.N. Herndon (1972 citations), and A.D. Mason Jr. (1435 citations) were the most cited authors. This study identified some of the most important contributions to burn research and the areas of greatest scientific interest to the specialty during the past five decades, and highlights key research that has contributed to the evolution of modern burn care.

Prehospital emergency inguinal clamp controls hemorrhage in cadaver model.

BACKGROUND: The Combat Ready Clamp is indicated to stop difficult inguinal bleeding on the battlefield, the most common type of junctional bleeding and now the most common cause of preventable battlefield death. The purpose of the present study is to report the data of clamp development to help appliers use it correctly. METHODS: Wake Forest University investigators used a cadaver model to test the clamp's ability to control hemorrhage. Ten fresh cadavers were made to simulate inguinal and popliteal wound bleeding. Blood simulant was pumped to quantify device effectiveness in testing. Points of application included proximal pressure point control of popliteal, inguinal, and bilateral bleeding. RESULTS: Clamp use promptly controlled pulsing arterial hemorrhages from inguinal, popliteal, and bilateral wounds. The device, when placed on the common iliac artery, stopped all ipsilateral distal bleeding. CONCLUSIONS: The evidence of how the clamp works in the cadaver model showed that clamp use can plausibly be tailored to control inguinal hemorrhage from one wound, control two ipsilateral wounds with hemorrhage from one artery (e.g., common iliac artery), and control bilateral inguinal wounds (compression of the origins of bilateral common iliac arteries).