Outcomes Associated With Aortic Balloon Occlusion Time in Patients With Zone 1 Resuscitative Endovascular Balloon Occlusion of the Aorta.

INTRODUCTION: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has the potential to cause clinically relevant systemic ischemic burden with long durations of aortic occlusion (AO). We aimed to examine the association between balloon occlusion time and clinical complications and mortality outcomes in patients undergoing zone 1 REBOA. METHODS: A retrospective cohort analysis of American Association for the Surgery of Trauma Aortic Occlusion for Resuscitation in Trauma and Acuteregistry patients with Zone 1 REBOA between 2013 and 2022 was performed. Patients with cardiopulmonary resuscitation on arrival or who did not survive past the emergency department were excluded. Total AO times were categorized as follows: <15 min, 15-30 min, 31-60 min, and >60 min. Clinical and procedural variables and in-hospital outcomes were compared across groups using bivariate and multivariate regression analyses. RESULTS: There were 327 cases meeting inclusion criteria (n = 51 < 15 min, 83 15-30 min, 98 31-60 min, and 95 > 60 min, respectively). AO >60 min had higher admission lactate (8 ± 6; P = 0.004) compared to all other time groups, but injury severity score, heart rate, and systolic blood pressure were similar. Group average times from admission to definitive hemorrhage control ranged from 82 to 103 min and were similar across groups (85 min in AO >60 group). Longer AO times were associated with greater red blood cell, fresh frozen plasma transfusions (P < 0.001), and vasopressor use (P = 0.001). Mortality was greatest in the >60 min group (73%) versus the <15 min, 15-30 min, and 31-60 min groups (53%, 43%, and 45%, P < 0.001). With adjustment for injury severity score, systolic blood pressure, and lactate, AO >60 min had greater mortality (OR 3.7, 95% CI 1.6-9.4; P < 0.001) than other AO duration groups. Among 153 survivors, AO >60 min had a higher rate of multiple organ failure (15.4%) compared to the other AO durations (0%, 0%, and 4%, P = 0.02). There were no differences in amputation rates (0.7%) or spinal cord ischemia (1.4%). acute kidney injury was seen in 41% of >60 min versus 21%, 27%, and 33%, P = 0.42. CONCLUSIONS: Though greater preocclusion physiologic injury may have been present, REBOA-induced ischemic insult was correlated with poor patient outcomes, specifically, REBOA inflation time >60 min had higher rates of mortality and multiple organ failure. Minimizing AO duration should be prioritized, and AO should not delay achieving definitive hemostasis. Partial REBOA may be a solution to extend safe AO time and deserves further study.

Randomized Controlled Trial of Surgical Rib Fixation to Nonoperative Management in Severe Chest Wall Injury.

OBJECTIVE: To compare the effectiveness of surgical stabilization of rib fractures (SSRFs) to nonoperative management in severe chest wall injury. BACKGROUND: SSRF has been shown to improve outcomes in patients with clinical flail chest and respiratory failure. However, the effect of SSRF outcomes in severe chest wall injuries without clinical flail chest is unknown. METHODS: Randomized controlled trial comparing SSRF to nonoperative management in severe chest wall injury, defined as: (1) a radiographic flail segment without clinical flail or (2) ≥5 consecutive rib fractures or (3) any rib fracture with bicortical displacement. Randomization was stratified by the unit of admission as a proxy for injury severity. Primary outcome was hospital length of stay (LOS). Secondary outcomes included intensive care unit (ICU) LOS, ventilator days, opioid exposure, mortality, and incidences of pneumonia and tracheostomy. Quality of life at 1, 3, and 6 months was measured using the EQ-5D-5L survey. RESULTS: Eighty-four patients were randomized in an intention-to-treat analysis (usual care = 42, SSRF = 42). Baseline characteristics were similar between groups. The numbers of total fractures, displaced fractures, and segmental fractures per patient were also similar, as were the incidences of displaced fractures and radiographic flail segments. Hospital LOS was greater in the SSRF group. ICU LOS and ventilator days were similar. After adjusting for the stratification variable, hospital LOS remained greater in the SSRF group (RR: 1.48, 95% CI: 1.17-1.88). ICU LOS (RR: 1.65, 95% CI: 0.94-2.92) and ventilator days (RR: 1.49, 95% CI: 0.61--3.69) remained similar. Subgroup analysis showed that patients with displaced fractures were more likely to have LOS outcomes similar to their usual care counterparts. At 1 month, SSRF patients had greater impairment in mobility [3 (2-3) vs 2 (1-2), P = 0.012] and self-care [2 (1-2) vs 2 (2-3), P = 0.034] dimensions of the EQ-5D-5L. CONCLUSIONS: In severe chest wall injury, even in the absence of clinical flail chest, the majority of patients still reported moderate to extreme pain and impairment of usual physical activity at one month. SSRF increased hospital LOS and did not provide any quality of life benefit for up to 6 months.

Arterial Access Complications Following Percutaneous Femoral Access in 24-Hour Resuscitative Endovascular Balloon Occlusion of the Aorta Survivors.

INTRODUCTION: With the use of resuscitative endovascular balloon occlusion of the aorta (REBOA) comes the potential for vascular access site complications (VASCs) and limb ischemic sequelae. We aimed to determine the prevalence of VASC and associated clinical and technical factors. METHODS: A retrospective cohort analysis of 24-h survivors undergoing percutaneous REBOA via the femoral artery in the American Association for the Surgery of Trauma Aortic Occlusion for Resuscitation in Trauma and Acute care surgery registry between Oct 2013 and Sep 2021 was performed. The primary outcome was VASC, defined as at least one of the following: hematoma, pseudoaneurysm, arteriovenous fistula, arterial stenosis, or the use of patch angioplasty for arterial closure. Associated clinical and procedural variables were examined. Data were analyzed using Fisher exact test, Mann-Whitney-U tests, and linear regression. RESULTS: There were 34 (7%) cases with VASC among 485 meeting inclusion criteria. Hematoma (40%) was the most common, followed by pseudoaneurysm (26%) and patch angioplasty (21%). No differences in demographics or injury/shock severity were noted between cases with and without VASC. The use of ultrasound (US) was protective (VASC, 35% versus no VASC, 51%; P = 0.05). The VASC rate in US cases was 12/242 (5%) versus 22/240 (9.2%) without US. Arterial sheath size >7 Fr was not associated with VASC. US use increased over time (R2 = 0.94, P < 0.001) with a stable rate of VASC (R2 = 0.78, P = 0.61). VASC were associated with limb ischemia (VASC, 15% versus no VASC, 4%; P = 0.006) and arterial bypass procedures (VASC 3% versus no VASC 0%; P < 0.001) but amputation was uncommon (VASC, 3% versus no VASC, 0.4%; P = 0.07). CONCLUSIONS: Percutaneous femoral REBOA had a 7% VASC rate which was stable over time. VASC are associated with limb ischemia but need for surgical intervention and/or amputation is rare. The use of US-guided access appears to be protective against VASC and is recommended for use in all percutaneous femoral REBOA procedures.

Prospective Observational Evaluation of the ER-REBOA Catheter at 6 U.S. Trauma Centers.

OBJECTIVE: To describe the current use of the ER-REBOA catheter and associated outcomes and complications. INTRODUCTION: Noncompressible truncal hemorrhage is the leading cause of potentially preventable death in trauma patients. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a novel strategy to obtain earlier temporary hemorrhage control, supporting cardiac, and cerebral perfusion before definitive hemostasis. METHODS: Prospective, observational study conducted at 6 Level 1 Trauma Centers over 12-months. Inclusion criteria were age >15 years of age with evidence of truncal hemorrhage below the diaphragm and decision for emergent hemorrhage control intervention within 60 minutes of arrival. REBOA details, demographics, mechanism of injury, complications, and outcomes were collected. RESULTS: A total of 8166 patients were screened for enrollment. In 75, REBOA was utilized for temporary hemorrhage control. Blunt injury occurred in 80% with a median injury severity score (ISS) 34 (21, 43). Forty-seven REBOAs were placed in Zone 1 and 28 in Zone 3. REBOA inflation increased systolic blood pressure from 67 (40, 83) mm Hg to 108 (90, 128) mm Hg 5 minutes after inflation (P = 0.02). Cardiopulmonary resuscitation was ongoing during REBOA insertion in 17 patients (26.6%) and 10 patients (58.8%) had return of spontaneous circulation after REBOA inflation. The procedural complication rate was 6.6%. Overall mortality was 52%. CONCLUSION: REBOA can be used in blunt and penetrating trauma patients, including those in arrest. Balloon inflation uniformly improved hemodynamics and was associated with a 59% rate of return of spontaneous circulation for patients in arrest. Use of the ER-REBOA catheter is technically safe with a low procedural complication rate.

Evaluation of Noninvasive Hemoglobin Measurements in Trauma Patients: A Repeat Study.

INTRODUCTION: Reliable, accurate, and non-invasive hemoglobin measurements would be useful in the trauma setting. The aim of this study was to re-examine the ability of the Masimo Radical 7 in this setting after recent hardware and software improvements. METHODS: Level 1 Trauma patients were prospectively enrolled in the study over a 9-mo period with the goal of obtaining 3 paired data points from 150 patients admitted to the ICU or IMU. Hospital laboratory hemoglobin values were compared with cyanomethemoglobin (HiCN) and Masimo device hemoglobin (SpHb) values using comparison plots and Bland-Altman analysis. RESULTS: A total of 380 patients were enrolled in the study with 150 of those being admitted to the ICU or IMU. Comparison of hospital lab hemoglobin and HiCN (n = 494) found a correlation of R2 = 0.92. Comparison of hospital lab hemoglobin and Masimo device hemoglobin (n = 218) found a correlation of R2 = 0.27. Bland-Altman analysis of the 218 of the comparable hospital hemoglobin and Masimo device hemoglobin values had a bias of 0.505 g/dL with 95% of values within the limits of agreement of 4.06 g/dL to -3.60 g/dL. CONCLUSIONS: The Masimo Radical 7 device has the potential to provide timely, useful clinical information, but it is not currently able to serve as an initial noninvasive diagnostic tool for trauma patients. There was poor correlation between clinical Hgb and SpHb, and because of that, SpHb should not be used to evaluate hemoglobin levels in trauma patients.

Accuracy of Published Indications for Predicting Use of Damage Control During Laparotomy for Trauma.

BACKGROUND: Although studies have identified published indications that experts and practicing surgeons agree indicate use of damage control (DC) laparotomy, it is unknown whether these indications predict use of the procedure in practice. MATERIALS AND METHODS: We conducted a diagnostic performance study of the accuracy of a set of published appropriateness indications for predicting use of DC laparotomy. We included consecutive adults that underwent emergent laparotomy for trauma (2011-2016) at Memorial Hermann Hospital. RESULTS: We included 1141 injured adults. Two published preoperative appropriateness indications [a systolic blood pressure (BP) persistently <90 mmHg or core body temperature <34°C] produced moderate shifts in the pretest probability of conducting DC instead of definitive laparotomy. Five published intraoperative appropriateness indications produced large and often conclusive changes in the pretest probability of conducting DC during emergent laparotomy. These included the finding of a devascularized or completely disrupted pancreas, duodenum, or pancreaticoduodenal complex; an estimated intraoperative blood loss >4 L; administration of >10 U of packed red blood cells (PRBCs); and a systolic BP persistently <90 mmHg or arterial pH persistently <7.2 during operation. Most indications that produced large changes in the pretest probability of conducting DC laparotomy had an incidence of 2% or less. CONCLUSIONS: This study suggests that published appropriateness indications accurately predict use of DC laparotomy in practice. Intraoperative variables exert greater influence on the decision to conduct DC laparotomy than preoperative variables, and those indications that produce large shifts in the pretest probability of conducting DC laparotomy are uncommonly encountered.

O2 availability impacts iron homeostasis in Escherichia coli.

The ferric-uptake regulator (Fur) is an Fe2+-responsive transcription factor that coordinates iron homeostasis in many bacteria. Recently, we reported that expression of the Escherichia coli Fur regulon is also impacted by O2 tension. Here, we show that for most of the Fur regulon, Fur binding and transcriptional repression increase under anaerobic conditions, suggesting that Fur is controlled by O2 availability. We found that the intracellular, labile Fe2+ pool was higher under anaerobic conditions compared with aerobic conditions, suggesting that higher Fe2+ availability drove the formation of more Fe2+-Fur and, accordingly, more DNA binding. O2 regulation of Fur activity required the anaerobically induced FeoABC Fe2+ uptake system, linking increased Fur activity to ferrous import under iron-sufficient conditions. The increased activity of Fur under anaerobic conditions led to a decrease in expression of ferric import systems. However, the combined positive regulation of the feoABC operon by ArcA and FNR partially antagonized Fur-mediated repression of feoABC under anaerobic conditions, allowing ferrous transport to increase even though Fur is more active. This design feature promotes a switch from ferric import to the more physiological relevant ferrous iron under anaerobic conditions. Taken together, we propose that the influence of O2 availability on the levels of active Fur adds a previously undescribed layer of regulation in maintaining cellular iron homeostasis.

Connectivity in coastal systems: Barrier island vegetation influences upland migration in a changing climate.

Due to their position at the land-sea interface, barrier islands are vulnerable to both oceanic and atmospheric climate change-related drivers. In response to relative sea-level rise, barrier islands tend to migrate landward via overwash processes which deposit sediment onto the backbarrier marsh, thus maintaining elevation above sea level. In this paper, we assess the importance of interior upland vegetation and sediment transport (from upland to marsh) on the movement of the marsh-upland boundary in a transgressive barrier system along the mid-Atlantic Coast. We hypothesize that recent woody expansion is altering the rate of marsh to upland conversion. Using Landsat imagery over a 32 year time period (1984-2016), we quantify transitions between land cover (bare, grassland, woody vegetation, and marsh) and the marsh-upland boundary. We find that the Virginia Barrier Islands have both gains and losses in backbarrier marsh and upland, with 19% net loss from the system during the timeframe of the study and increased variance in marsh to upland conversion. This is consistent with recent work indicating a shift toward increasing rates of landward barrier island migration. Despite a net loss of upland area, macroclimatic winter warming resulted in 41% increase in woody vegetation in protected, low-elevation areas, introducing new ecological scenarios that increase resistance to sediment movement from upland to marsh. Our analysis demonstrates how the interplay between elevation and interior island vegetative cover influences landward migration of the boundary between upland and marsh (a previously underappreciated indicator that an island is migrating), and thus, the importance of including ecological processes in the island interior into coastal modeling of barrier island migration and sediment movement across the barrier landscape.

Resuscitative Endovascular Balloon Occlusion of the Aorta: Principles, Initial Clinical Experience, and Considerations for the Anesthesiologist.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an endovascular technique that allows for temporary occlusion of the aorta in patients with severe, life-threatening, trauma-induced noncompressible hemorrhage arising below the diaphragm. REBOA utilizes a transfemoral balloon catheter inserted in a retrograde fashion into the aorta to provide inflow control and support blood pressure until definitive hemostasis can be achieved. Initial retrospective and registry clinical data in the trauma surgical literature demonstrate improvement in systolic blood pressure with balloon inflation and improved survival compared to open aortic cross-clamping via resuscitative thoracotomy. However, there are no significant reports of anesthetic implications and perioperative management in this challenging cohort. In this narrative, we review the principles, technique, and logistics of REBOA deployment, as well as initial clinical outcome data from our level-1 American College of Surgeons-verified trauma center. For anesthesiologists who may not yet be familiar with REBOA, we make several suggestions and recommendations for intraoperative management based on extrapolation from these initial surgical-based reports, opinions from a team with increasing experience, and translated experience from emergency aortic vascular surgical procedures. Further prospective data will be necessary to conclusively guide anesthetic management, especially as potential complications and implications for global organ function, including cerebral and renal, are recognized and described.

Vegetation controls on the maximum size of coastal dunes.

Coastal dunes, in particular foredunes, support a resilient ecosystem and reduce coastal vulnerability to storms. In contrast to dry desert dunes, coastal dunes arise from interactions between biological and physical processes. Ecologists have traditionally addressed coastal ecosystems by assuming that they adapt to preexisting dune topography, whereas geomorphologists have studied the properties of foredunes primarily in connection to physical, not biological, factors. Here, we study foredune development using an ecomorphodynamic model that resolves the coevolution of topography and vegetation in response to both physical and ecological factors. We find that foredune growth is eventually limited by a negative feedback between wind flow and topography. As a consequence, steady-state foredunes are scale invariant, which allows us to derive scaling relations for maximum foredune height and formation time. These relations suggest that plant zonation (in particular for strand "dune-building" species) is the primary factor controlling the maximum size of foredunes and therefore the amount of sand stored in a coastal dune system. We also find that aeolian sand supply to the dunes determines the timescale of foredune formation. These results offer a potential explanation for the empirical relation between beach type and foredune size, in which large (small) foredunes are found on dissipative (reflective) beaches. Higher waves associated with dissipative beaches increase the disturbance of strand species, which shifts foredune formation landward and thus leads to larger foredunes. In this scenario, plants play a much more active role in modifying their habitat and altering coastal vulnerability than previously thought.

Validation of sepsis screening tool using StO2 in emergency department patients.

BACKGROUND: Sepsis is a deleterious systemic response to an infection with a high incidence of morbidity and mortality, affecting more than a million patients a year in the US. The purpose of this study was to develop a screening tool for the early identification of sepsis in emergency department patients using readily available information at triage. MATERIALS AND METHODS: This prospective, observational study took place at an academic tertiary referral hospital. Over a period of 10 wk, all patients who were seen at triage were screened for study enrollment. Inclusion criteria were adult (age≥18 y) nontrauma patients and exclusion criteria were prisoners and pregnant women. Using a Spot Check StO2 device to measure StO2 value, heart rate, respiratory rate, and temperature, these values were used to generate a cumulative screening score indicating whether a patient may have sepsis. RESULTS: A total of 500 patients were screened. The incidence of sepsis in the present study population was 8.4%. The screening tool yielded a sensitivity of 85.7%, a specificity of 78.4%, a positive predictive value of 26.7%, and a negative predictive value of 98.4%. CONCLUSIONS: Heart rate, respiratory rate, and temperature have good diagnostic potential for the early identification of sepsis among emergency department triage personnel. Additionally, early evidence suggests StO2 may play a complementary and synergistic role in the early identification of sepsis by triage personnel.

The geriatric trauma hospitalist service: An analysis of a management strategy for injured older adults.

BACKGROUND: Management of geriatric trauma patients requires balancing chronic comorbidities with acute injuries. We developed a care model in which patients are managed by hospitalists with trauma-centered education and hypothesized that clinical outcomes would be similar to outcomes in patients primarily managed by trauma surgeons. METHODS: This was a retrospective study of trauma patients aged ≥65 from January 2020 to December 2021. Groups were defined by admitting service: trauma surgery service (TSS) or geriatric trauma hospitalist service (GTHS). The primary outcome was in-hospital mortality. Regression analyses and inverse probability treatment weighted (IPTW) propensity score (PS) analyses were performed to determine the association between admitting service and outcomes. RESULTS: A total of 1004 patients were eligible for inclusion-580 GTHS and 424 TSS admissions. GTHS patients were older (82 vs. 74, p < 0.001), more likely to have suffered blunt trauma (99.5% vs. 95%, p < 0.001), more likely to have comorbidities (91.2% vs. 87%, p < 0.001), had higher Charlson Comorbidity Indexes (CCIs), and had lower median injury severity scores (9 vs. 13, p < 0.001). Rates of mortality, delirium, 30-day readmission, and overall complications were low and similar between groups. While TSS patients were likely to be discharged home, GTHS had more discharges to skilled nursing facilities and longer length of stay (LOS). On multivariable analysis adjusted for age, ISS, CCI, and sex, patients admitted to GTHS had lower odds of death with an odds ratio of 0.15 (95% confidence interval [CI] 0.02-0.75, p = 0.03) when compared to TSS. On IPTW PS analysis, patients admitted to GTHS had similar odds of death with an odds ratio of 0.3 (95% CI 0.06-1.6, p = 0.16). CONCLUSIONS: Protocolized admission criteria to a GTHS resulted in similar low mortality rates but longer LOS when compared to patients admitted to a TSS. This care model may inform other trauma centers in developing their strategies for managing the increasing volume of vulnerable injured older adults.

A focused curriculum in surgical oncology for the third-year medical students.

BACKGROUND: Educating medical students in surgical subspecialty fields can be challenging, and the optimal timing and curriculum remain unknown. Despite advocacy for earlier exposure, competing core clerkship rotations often leave little time for subspecialty fields. We report our experience with a novel, short, and focused curriculum in surgical oncology for the third-year medical students. METHODS: A 2-wk (2009-2010) and a 4-wk (2010-2011) curriculum in surgical oncology were developed for the third-year students at a tertiary-referral cancer center, including formal didactics, rotation in clinical service of students' choosing (breast, gastrointestinal, endocrine, or melanoma), and case-based learning and presentation. Paired pre- and postrotation questionnaires were prospectively completed, including 20 items assessing knowledge and four items assessing experience. Grading was anonymous, and change in score was assessed by Wilcoxon signed-rank test. RESULTS: Paired questionnaires from 47 students (2-wk rotation, n = 26; 4-wk rotation, n = 21) showed a median improvement of three points (21.4%) from pre- to posttests (P < 0.001). The improvement did not differ by the length of rotation or by the specific clinical service. Nearly all (93%) reported a positive and inspiring experience. The most valuable avenue of learning was reported as the time spent with resident or fellow or attending (92%), followed by self-directed reading (62%) and didactic lectures (28%). CONCLUSIONS: A short and focused curriculum in surgical oncology, including structured didactics and clinical rotation, had positive impact for the third-year students. Given the increasing work-hour limits, it is important to note that the time spent in the clinical setting continues to be ranked as the most educationally valuable by medical students.

Early diagnosis and evidence-based care of surgical sepsis.

Sepsis continues to be a common and serious problem among surgical patients. It is a leading cause of both morbidity and mortality in the perioperative period. The early identification of sepsis and the early implementation of evidence-based care can improve outcomes. This focused review will identify ways to improve the early identification of sepsis and discuss the current evidence-based guidelines for the early management of sepsis, severe sepsis, and septic shock in the surgical patients.

The reports of my death are greatly exaggerated: An evaluation of futility cut points in massive transfusion.

BACKGROUND: Following COVID and the subsequent blood shortage, several investigators evaluated futility cut points in massive transfusion. We hypothesized that early aggressive use of damage-control resuscitation, including whole blood (WB), would demonstrate that these cut points of futility were significantly underestimating potential survival among patients receiving >50 U of blood in the first 4 hours. METHODS: Adult trauma patients admitted from November 2017 to October 2021 who received emergency-release blood products in prehospital or emergency department setting were included. Deaths within 30 minutes of arrival were excluded. Total blood products were defined as total red blood cell, plasma, and WB in the field and in the first 4 hours after arrival. Patients were first divided into those receiving ≤50 or >50 U of blood in the first 4 hours. We then evaluated patients by whether they received any WB or received only component therapy. Thirty-day survival was evaluated for all included patients. RESULTS: A total of 2,299 patients met the inclusion criteria (2,043 in ≤50 U, 256 in >50 U groups). While there were no differences in age or sex, the >50 U group was more likely to sustain penetrating injury (47% vs. 30%, p < 0.05). Patients receiving >50 U of blood had lower field and arrival blood pressure and larger prehospital and emergency department resuscitation volumes ( p < 0.05). Patients in the >50 U group had lower survival than those in the ≤50 cohort (31% vs. 79%; p < 0.05). Patients who received WB (n = 1,291) had 43% increased odds of survival compared with those who received only component therapy (n = 1,008) (1.09-1.87, p = 0.009) and higher 30-day survival at transfusion volumes >50 U. CONCLUSION: Patient survival rates in patients receiving >50 U of blood in the first 4 hours of care are as high as 50% to 60%, with survival still at 15% to 25% after 100 U. While responsible blood stewardship is critical, futility should not be declared based on high transfusion volumes alone. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level III.

Blood, balloons, and blades: State of the art trauma resuscitation.

Traumatic injury remains the leading cause of death in patients 45 and younger. State of the art trauma care requires rapid interventions to provide hemodynamic support en route to definitive hemostasis. This article will review three critical elements in management of the bleeding trauma patient: blood products, resuscitative endovascular balloon occlusion of the aorta (REBOA), and the trauma hybrid operating room (THOR).

Cushioned on the way up, controlled on the way down during resuscitative endovascular balloon occlusion of the aorta (REBOA): investigating a novel compliant balloon design for optimizing safe overinflation combined with partial REBOA ability.

Background: There are a variety of devices capable of performing resuscitative endovascular balloon occlusion of the aorta (REBOA), with most containing compliant balloon material. While compliant material is ideal for balloon inflation due to its "cushioning" effect, it can be problematic to "control" during deflation. The COBRA-OS (Control Of Bleeding, Resuscitation, Arterial Occlusion System) was designed to optimize inflation and deflation of its compliant balloon and was tested in vitro and in vivo with respect to its overinflation and partial REBOA abilities. Methods: For overinflation, the COBRA-OS was inflated in three differently sized inner diameter (ID) vinyl tubes until balloon rupture. It was then overinflated in six harvested swine aortas and in all three REBOA zones of three anesthetized swine. For partial REBOA, the COBRA-OS underwent incremental deflation in a pulsatile benchtop aortic model and in zone 1 of three anesthetized swine. Results: For overinflation, compared with the known aortic rupture threshold of 4 atm, the COBRA-OS exceeded this value in only the smallest of the vinyl tubes: 8 mm ID tube, 6.5 atm; 9.5 mm ID tube, 3.5 atm; 13 mm ID tube, 1.5 atm. It also demonstrated greater than 500% overinflation ability without aortic damage in vitro and caused no aortic damage when inflated to maximum inflation volume in vivo. For partial REBOA, the COBRA-OS was able to provide a titration window of between 3 mL and 4 mL in both the pulsatile vascular model (3.4±0.12 mL) and anesthetized swine (3.8±0.35 mL). Discussion: The COBRA-OS demonstrated the ability to have a cushioning effect during inflation combined with titration control on deflation in vitro and in vivo. This study suggests that despite its balloon compliance, both safe overinflation and partial REBOA can be successfully achieved with the COBRA-OS. Level of evidence: Basic science.

Resuscitative Endovascular Balloon Occlusion of the Aorta in Penetrating Trauma.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) achieves temporary hemorrhage control via aortic occlusion. Existing REBOA literature focuses on blunt trauma without a clearly defined role in penetrating trauma. This study compared clinical/injury data and outcomes after REBOA in penetrating vs blunt trauma. STUDY DESIGN: All patients in the Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery (AORTA) database, an observational American Association for the Surgery of Trauma dataset of trauma patients requiring aortic occlusion, who underwent REBOA were included (January 2014 through February 2021). Study groups were defined by mechanism: penetrating vs blunt. Subgroup analysis was performed of patients arriving with vital signs. Univariable/multivariable analyses compared injuries and outcomes. RESULTS: Seven hundred fifty-nine patients underwent REBOA: 152 (20%) penetrating and 607 (80%) blunt. Patients undergoing penetrating REBOA were less severely injured (injury severity score 25 vs 34; p < 0.001). The most common hemorrhage source was abdominal in penetrating REBOA (79%) and pelvic in blunt REBOA (31%; p = 0.002). Penetrating REBOA was more likely to occur in the operating room (36% vs 17%) and less likely in the emergency department (63% vs 81%; p < 0.001). Penetrating REBOA used more zone I balloon deployment (76% vs 64%) and less zone III (19% vs 34%; p = 0.001). Improved or stabilized hemodynamics were less frequent after penetrating REBOA (41% vs 62%, p < 0.001; 23% vs 41%, p < 0.001). On subgroup analysis of patients arriving alive, improvement or stabilization in hemodynamics was similar between groups (87% vs 86%, p = 0.388; 77% vs 72%, p = 0.273). Penetrating REBOA was not independently associated with mortality (odds ratio 1.253; p = 0.776). CONCLUSIONS: Despite lower injury severity, REBOA was significantly less likely to improve or stabilize hemodynamics after penetrating trauma. Among patients arriving alive, however, outcomes were comparable, suggesting that penetrating REBOA may be most beneficial among patients with vital signs. Because hemorrhage source, catheter insertion setting, and deployment zone varied significantly between groups, existing blunt REBOA data may not be appropriately extrapolated to penetrating trauma. Further study of REBOA as a means of aortic occlusion in penetrating trauma is needed.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) may be superior to resuscitative thoracotomy (RT) in patients with traumatic brain injury (TBI).

Background: The effects of aortic occlusion (AO) on brain injury are not well defined. We examined the impact of AO by resuscitative endovascular balloon occlusion of the aorta (REBOA) and resuscitative thoracotomy (RT) on outcomes in the setting of traumatic brain injury (TBI). Methods: Patients sustaining TBI who underwent RT or REBOA in zone 1 (thoracic aorta) from September 2013 to December 2018 were identified. The indication for REBOA or RT was hemodynamic collapse due to hemorrhage below the diaphragm. Primary outcomes included mortality and systemic complications. Results: 282 patients underwent REBOA or RT. Of these, 76 had mild TBI (40 REBOA, 36 RT) and 206 sustained severe TBI (107 REBOA, 99 RT). Overall, the mean (±SD) age was 42±17 years, with an Injury Severity Score (ISS) of 40±17 and mean systolic blood pressure (SBP) at the time of REBOA or RT of 81±34 mm Hg. REBOA patients had a mean SBP at the time of AO of 78.39±29.45 mm Hg, whereas RT patients had a mean SBP of 83.18±37.87 mm Hg at the time of AO (p=0.24). 55% had ongoing cardiopulmonary resuscitation (CPR) at the time of AO, and the in-hospital mortality was 86%. Binomial logistic regression controlling for TBI severity, age, ISS, SBP at the time of AO, crystalloid infusion, and CPR during AO demonstrated that the odds of mortality are 3.1 times higher for RT compared with REBOA. No significant differences were found in systemic complications between RT and REBOA. Discussion: Patients with TBI who receive REBOA may have improved survival, but no difference in systemic complications, compared with patients who receive RT for the same indication. Although some patients are receiving RT prior to arrest for extrathoracic hemorrhagic shock, these results suggest that REBOA should be considered as an alternative to RT when RT is chosen for the sole purpose of resuscitation in the setting of TBI. Level of evidence: 4.

Survival benefit for pelvic trauma patients undergoing Resuscitative Endovascular Balloon Occlusion of the Aorta: Results of the AAST Aortic Occlusion for Resuscitation in Trauma Acute Care Surgery (AORTA) Registry.

BACKGROUND: Aortic occlusion (AO) to facilitate the acute resuscitation of trauma and acute care surgery patients in shock remains a controversial topic. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is an increasingly deployed method of AO. We hypothesized that in patients with non-compressible hemorrhage below the aortic bifurcation, the use of REBOA instead of open AO may be associated with a survival benefit. METHODS: From the AAST Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery (AORTA) registry, we identified 1494 patients requiring AO from 45 Level I and 4 Level II trauma centers. Presentation, intervention, and outcome variables were analyzed to compare REBOA vs open AO in patients with non-compressible hemorrhage below the aortic bifurcation. RESULTS: From December 2014 to January 2019, 217 patients with Zone 3 REBOA or Open AO who required pelvic packing, pelvic fixation or pelvic angio-embolization were identified. Of these, 109 AO patients had injuries isolated to below the aortic bifurcation (REBOA, 84; open AO, 25). Patients with intra-abdominal or thoracic sources of bleeding, above deployment Zone 3 were excluded. Overall mortality was lower in the REBOA group (35.% vs 80%, p <.001). Excluding patients who arrived with CPR in progress, the REBOA group had lower mortality (33.33% vs. 68.75%, p = 0.012). Of the survivors, systemic complications were not significantly different between groups. In the REBOA group, 16 patients had complications secondary to vascular access. Intensive care lengths of stay and ventilator days were both significantly shorter in REBOA patients who survived to discharge. CONCLUSIONS: This study compared outcomes for patients with hemorrhage below the aortic bifurcation treated with REBOA to those treated with open AO. Survival was significantly higher in REBOA patients compared to open AO patients, while complications in survivors were not different. Given the higher survival in REBOA patients, we conclude that REBOA should be used for patients with hemorrhagic shock secondary to pelvic trauma instead of open AO. LEVEL III EVIDENCE: Therapeutic.