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.

Balloon Rises Above: REBOA at Zone 1 May Be Superior to Resuscitative Thoracotomy.

BACKGROUND: The use of Zone 1 REBOA for life-threatening trauma has increased dramatically. STUDY DESIGN: The Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery database was queried for blunt and penetrating trauma between 2013 and 2021. Outcomes were examined both for mechanisms of injury combined and separately and for combinations of abdominal injury with and without traumatic brain injury and chest injuries (Abbreviated Injury Scale [AIS] score >2). RESULTS: A total of 531 patients underwent REBOA (408 with blunt injury and 123 with penetrating injury) and 1,603 (595 with blunt injury and 1,008 with penetrating injury) underwent resuscitative thoracotomy (RT). Mean age was 38.5 ± 16 years and mean injury severity score was 34.5 ± 21; 57.7% had chest AIS score of more than 2, 21.8% had head AIS score of more than 2, and 37.3% had abdominal AIS score of more than 2. Admission Glasgow Coma Scale was 4.9 + 4, and systolic blood pressure at aortic occlusion (AO) was 22 + 40 mmHg. No differences in outcomes in REBOA or RT patients were identified between institutions (p > 0.5). After inverse probability weighting, Glasgow Coma Scale, age, injury severity score, systolic blood pressure at AO, CPR at AO, and blood product transfusion, REBOA was superior to RT in both blunt (odds ratio [OR] 4.7, 95% CI 1.9 to 11.7) and penetrating (OR 4.9, 95% CI 1.7 to 14) injuries, across all spectrums of injury (p < 0.01). Overall mortality was significantly higher for AO more than 90 minutes compared with less than 30 minutes in blunt (OR 4.6, 95% CI 1.5 to 15) and penetrating (OR 5.4, 95% CI 1.1 to 25) injuries. Duration of AO more than 60 minutes was significantly associated with mortality after penetrating abdominal injury (OR 5.1, 95% CI 1.1 to 22) and abdomen and head (OR 5.3, 95% CI 1.6 to 18). CONCLUSIONS: In-hospital survival is higher for patients undergoing REBOA than RT for all injury patterns. Complete AO by REBOA or RT should be limited to less than 30 minutes. Neither hospital and procedure volume nor trauma verification level impacts outcomes for REBOA or RT.

Hair Collection for Cortisol Among Youth Experiencing Homelessness.

BACKGROUND: Investigations of chronic physiological stress measured by hair cortisol are rapidly expanding among community samples of adolescents and adults. However, research examining physiological stress among youth experiencing homelessness is nascent despite the youth's increased risk for adverse exposures and subsequent impaired mental health. OBJECTIVE: This article aimed to examine the feasibility of collecting hair for measuring cortisol among diverse youth experiencing homelessness and gain an understanding of variation in participation. METHODS: Analysis of survey and hair participation data from three pilot studies among youth experiencing homelessness was conducted. Survey measures included sociodemographic characteristics (age, race and ethnicity, sex assigned at birth, and sexual orientation) and reasons for nonparticipation. Descriptive analysis examined participation rates in hair collection for cortisol measurement, including sociodemographic differences in participation. RESULTS: Participation in the hair sampling for cortisol was high for the combined sample (88.4%), with some variation across the three pilot studies. Insufficient hair for cutting was the most common reason for not participating; Black and multiracial youth, as well as male youth, had a higher prevalence of nonparticipation. DISCUSSION: The collection of hair for cortisol research among youth experiencing homelessness is feasible, and integration of physiological measures of stress into research with this vulnerable population should be considered, given their high risk for adversity and death by suicide and drug overdose. Methodological considerations and avenues for potential research are discussed.

Use of Tranexamic Acid With Resuscitative Endovascular Balloon Occlusion of the Aorta is Associated With Higher Distal Embolism Rates: Results From the American Association of Surgery for Trauma Aortic Occlusion and Resuscitation for Trauma and Acute Care Surgery Trial.

INTRODUCTION: Tranexamic acid (TXA) use has been associated with thrombotic complications. OBJECTIVE: We aim to investigate outcomes associated with TXA use in the setting of high- (HP) and low-profile (LP) introducer sheaths for resuscitative endovascular balloon occlusion of the aorta (REBOA). PARTICIPANTS: The Aortic Occlusion and Resuscitation for Trauma and Acute Care Surgery (AORTA) database was queried for patients who underwent REBOA using a low-profile 7 French (LP) or high-profile, 11-14 French (HP) introducer sheaths between 2013 and 2022. Demographics, physiology, and outcomes were examined for patients who survived beyond the index operation. RESULTS: 574 patients underwent REBOA (503 LP, 71 HP); 77% were male, mean age was 44 ± 19 and mean injury severity score (ISS) was 35 ± 16. 212 patients received TXA (181 [36%] LP, 31 [43.7%] HP). There were no significant differences in admission vital signs, GCS, age, ISS, SBP at AO, CPR at AO, and duration of AO among LP and HP patients. Overall, mortality was significantly higher in the HP (67.6%) vs the LP group (54.9%; P = .043). Distal embolism was significantly higher in the HP group (20.4%) vs the LP group (3.9%; P < .001). Logistic regression demonstrated that TXA use was associated with a higher rate of distal embolism in both groups (OR = 2.92; P = .021). 2 LP patients (one who received TXA) required an amputation. CONCLUSION: Patients who undergo REBOA are profoundly injured and physiologically devastated. Tranexamic acid was associated with a higher rate of distal embolism in those who received REBOA, regardless of access sheath size. For patients receiving TXA, REBOA placement should be accompanied by strict protocols for immediate diagnosis and treatment of thrombotic complications.

An evaluation of the Compassion, Inclusion, and Engagement initiative: learning from PWLE and communities across British Columbia.

BACKGROUND: The Compassion, Inclusion and Engagement initiative (CIE) was a social contact intervention that operated in British Columbia between 2015 and 2021. The primary objective of CIE was to increase the participation of people with lived experience of substance use (PWLE) in the planning, design, implementation, and evaluation of harm reduction supports and services. CASE PRESENTATION: CIE used the developmental evaluation methodology outcome mapping to define and measure progress towards its goals. Developmental evaluation emphasizes learning in contrast to other forms of evaluation which are often more focused on determining the value or success of a project or programme based on predetermined criteria. Outcome mapping is a relational practice which acknowledges that change is achieved by an initiative's partners and the role of the initiative is to provide access to resources, ideas and opportunities that can facilitate and support change. CONCLUSIONS: Through the implementation and evaluation of CIE, it became clear that directly supporting PWLE facilitated more meaningful and lasting change than solely working to improve the health and social services that supported them. The impacts of the CIE initiative extend far beyond the outcomes of any of the dialogues it facilitated and are largely the result of an increase in social capital. CIE engagements created the opportunity for change by inviting people most affected by the toxic drug supply together with those committed to supporting them, but their ability to bring about systemic change was limited. Both PWLE and service providers noted the lack of support to attend CIE engagements, lack of support for actions that came from those engagements, and lack of PWLE inclusion in decision-making by health authorities as limiting factors for systemic change. The lack of response at a systemic level often resulted in PWLE carrying the burden of responding to toxic drug poisonings, often without resources, support, or compensation.

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.

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.

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.

Mental Health Professionals' Experiences of Adapting Mental Health Interventions for Autistic Adults: A Systematic Review and Thematic Synthesis.

Autistic adults experience high rates of metal health difficulties and face significant barriers to accessing appropriate mental health care. Empirical research and recent professional guidelines emphasise the importance of modifying standard mental health interventions to best meet the needs of autistic adults. This systematic review explored mental health professionals' experiences of adapting mental health interventions for autistic adults. A systematic search was conducted on CINAHL, PsychINFO, PubMed, Scopus, and Web of Science in July 2022. The findings from 13 identified studies were synthesised using thematic synthesis. Three major analytical themes were generated, the unique experience of adapting interventions for autistic clients, factors which facilitate successful adaptations, and challenges to adapting interventions. Each theme contained a number of subsequent sub-themes. Professionals view the process of adapting interventions to be a highly individualised process. A range of personal traits, professional experiences, and systemic, service-based issues were identified in facilitating or challenging this individualised process. Further research regarding adaptations with different intervention models and increased supportive resources are required to enable professionals to successfully adapt interventions for autistic adult clients.

Introducing mirror-image discrimination capability to the TSR-based method for capturing stereo geometry and understanding hierarchical structure relationships of protein receptor family.

We have developed a Triangular Spatial Relationship (TSR)-based computational method for protein structure comparison and motif discovery that is both sequence and structure alignment-free. A protein 3D structure is modeled by all possible triangles that are constructed with every three Cα atoms of amino acids as vertices. Every triangle is represented using an integer (a key). The keys are calculated by a rule-based formula which is a function of a representative length, a representative angle, and the vertex labels associated with amino acids. A 3D structure is thereby represented by a vector of integers (TSR keys). Global or local structure comparisons are achieved by computing all keys or a set of keys, respectively. Many enzymatic reactions and notable marketed drugs are highly stereospecific. Thus, in this paper, we propose a modified key calculation formula by including a mechanism for discriminating mirror-image keys to capture stereo geometry. We assign a positive or a negative sign to the integers representing mirror-image keys. Applying the new key calculation function provides the ability to further discriminate mirror-image keys that were previously considered identical. As the result, applying the mirror-image discrimination capability (i) significantly increases the number of distinct keys; (ii) decreases the number of common keys; (iii) decreases structural similarity; (iv) increases the opportunity to identify specific keys for each type of the receptors. The specific keys identified in this study for the cases of without (not applying) and with (applying) mirror-image discrimination can be considered as the structure signatures that exclusively belong to a certain type of receptors. Applying mirror-image discrimination introduces stereospecificity to keys for allowing more precise modeling of ligand - target interactions. The development of mirror-image TSR keys of Cα atom, in conjunction with the integration of Cα TSR keys with all-atom TSR keys for amino acids and drugs, will lead to a new and promising computational method for aiding drug design and discovery.

Evidence-based practice improves patient outcomes and healthcare system return on investment: Findings from a scoping review.

BACKGROUND: Evidence-based practice and decision-making have been consistently linked to improved quality of care, patient safety, and many positive clinical outcomes in isolated reports throughout the literature. However, a comprehensive summary and review of the extent and type of evidence-based practices (EBPs) and their associated outcomes across clinical settings are lacking. AIMS: The purpose of this scoping review was to provide a thorough summary of published literature on the implementation of EBPs on patient outcomes in healthcare settings. METHODS: A comprehensive librarian-assisted search was done with three databases, and two reviewers independently performed title/abstract and full-text reviews within a systematic review software system. Extraction was performed by the eight review team members. RESULTS: Of 8537 articles included in the review, 636 (7.5%) met the inclusion criteria. Most articles (63.3%) were published in the United States, and 90% took place in the acute care setting. There was substantial heterogeneity in project definitions, designs, and outcomes. Various EBPs were implemented, with just over a third including some aspect of infection prevention, and most (91.2%) linked to reimbursement. Only 19% measured return on investment (ROI); 94% showed a positive ROI, and none showed a negative ROI. The two most reported outcomes were length of stay (15%), followed by mortality (12%). LINKING EVIDENCE TO ACTION: Findings indicate that EBPs improve patient outcomes and ROI for healthcare systems. Coordinated and consistent use of established nomenclature and methods to evaluate EBP and patient outcomes are needed to effectively increase the growth and impact of EBP across care settings. Leaders, clinicians, publishers, and educators all have a professional responsibility related to improving the current state of EBP. Several key actions are needed to mitigate confusion around EBP and to help clinicians understand the differences between quality improvement, implementation science, EBP, and research.

Evaluation, Treatment, and Outcomes of Batter's Shoulder.

PURPOSE OF REVIEW: This article reviews the incidence of batter's shoulder, the relevant biomechanics that predispose the lead shoulder to a posterior instability event, the evaluation and workup of posterior labral injury, the surgical technique for arthroscopic posterior labral repair, the postoperative rehabilitation process, and the clinical outcomes and return to sport after treatment of batter's shoulder. RECENT FINDINGS: New epidemiological studies have demonstrated the relatively low incidence of batter's shoulder at the professional baseball level with 85% of the injured players successfully returning to the sport with nonoperative management. However, recent studies have reinforced the limited historical literature that players requiring surgery are able to return to their prior sport at a high level. Batter's shoulder is a subtype of posterior glenohumeral instability caused by the significant forces experienced by the lead shoulder during the baseball swing. Although an uncommon injury, batter's shoulder is a source of significant time away from competition. In patients who do not improve with nonoperative management, arthroscopic posterior labral repair can reliably return players to sport. Future research studies should consider opportunities for injury prevention.

Mindfulness stress-buffering model of health: implications for successful aging.

OBJECTIVES: Age-related variations in emotional, physical, and cognitive health are poorly understood. This multimethod study extends previous work by investigating mechanistic models by which trait mindfulness, perceived stress, and negative affect (NA) influence health outcomes in adults aged 57-87 years old. METHOD: In this cross-sectional study, 119 adults completed clinical interviews, cognitive and gait assessments, the Mindful Attention and Awareness Scale, Positive and Negative Affect Schedule, and Perceived Stress Scale. Gait velocity and executive function (Flanker test of inhibitory control), which are important predictors of global health and functioning in older adults, served as objective health outcome measures. RESULTS: Correlational analyses found that trait mindfulness is positively associated with age, gait velocity, and inhibitory control and negatively associated with NA and perceived stress. NA but not perceived stress was associated with slower gait velocity. PROCESS mediation analyses suggested that those higher in trait mindfulness showed lower NA as a result of less perceived stress, while moderation analyses indicated the relationship between gait velocity and age varied by levels of trait mindfulness. CONCLUSION: Our findings are consistent with a mindfulness stress-buffering model of health. It is plausible that trait mindfulness, which has both mediating and moderating effects on health, might help to promote more successful aging and provide resilience to age-related declines in physical health.

Pulsatile tympanic membrane displacement is associated with cognitive score in healthy subjects.

To test the hypothesis that pulsing of intracranial pressure has an association with cognition, we measured cognitive score and pulsing of the tympanic membrane in 290 healthy subjects. This hypothesis was formed on the assumptions that large intracranial pressure pulses impair cognitive performance and tympanic membrane pulses reflect intracranial pressure pulses. 290 healthy subjects, aged 20-80 years, completed the Montreal Cognitive Assessment Test. Spontaneous tympanic membrane displacement during a heart cycle was measured from both ears in the sitting and supine position. We applied multiple linear regression, correcting for age, heart rate, and height, to test for an association between cognitive score and spontaneous tympanic membrane displacement. Significance was set at P < 0.0125 (Bonferroni correction.) A significant association was seen in the left supine position (p = 0.0076.) The association was not significant in the right ear supine (p = 0.28) or in either ear while sitting. Sub-domains of the cognitive assessment revealed that executive function, language and memory have been primarily responsible for this association. In conclusion, we have found that spontaneous pulses of the tympanic membrane are associated with cognitive performance and believe this reflects an association between cognitive performance and intracranial pressure pulses.

Frozen shoulder.

Frozen shoulder is a common debilitating disorder characterized by shoulder pain and progressive loss of shoulder movement. Frozen shoulder is frequently associated with other systemic conditions or occurs following periods of immobilization, and has a protracted clinical course, which can be frustrating for patients as well as health-care professionals. Frozen shoulder is characterized by fibroproliferative tissue fibrosis, whereby fibroblasts, producing predominantly type I and type III collagen, transform into myofibroblasts (a smooth muscle phenotype), which is accompanied by inflammation, neoangiogenesis and neoinnervation, resulting in shoulder capsular fibrotic contractures and the associated clinical stiffness. Diagnosis is heavily based on physical examination and can be difficult depending on the stage of disease or if concomitant shoulder pathology is present. Management consists of physiotherapy, therapeutic modalities such as steroid injections, anti-inflammatory medications, hydrodilation and surgical interventions; however, their effectiveness remains unclear. Facilitating translational science should aid in development of novel therapies to improve outcomes among individuals with this debilitating condition.

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.