Strategies for successful implementation of resuscitative endovascular balloon occlusion of the aorta in an urban Level I trauma center.

BACKGROUND: The rationale for resuscitative endovascular balloon occlusion of the aorta (REBOA) is to control life-threatening subdiaphragmatic bleeding and facilitate resuscitation; however, incorporating this into the resuscitative practices of a trauma service remains challenging. The objective of this study is to describe the process of successful implementation of REBOA use in an academic urban Level I trauma center. All REBOA procedures from April 2014 through December 2019 were evaluated; REBOA was implemented after surgical faculty attended a required and internally developed Advanced Endovascular Strategies for Trauma Surgeons course. Success was defined by sustained early adoption rates. METHODS: An institutional protocol was published, and a REBOA supply cart was placed in the emergency department with posters attached to depict technical and procedural details. A focused professional practice evaluation was utilized for the first three REBOA procedures performed by each faculty member, leading to internal privileging. RESULTS: Resuscitative endovascular balloon occlusion of the aorta was performed in 97 patients by nine trauma surgeons, which is 1% of the total trauma admissions during this time. Each surgeon performed a median of 12 REBOAs (interquartile range, 5-14). Blunt (77/97, 81%) or penetrating abdominopelvic injuries (15/97, 15%) comprised the main injury mechanisms; 4% were placed for other reasons (4/97), including ruptured abdominal aortic aneurysms (n = 3) and preoperatively for a surgical oncologic resection (n = 1). Overall survival was 65% (63/97) with a steady early adoption trend that resulted in participation in a Department of Defense multicenter trial. CONCLUSION: Strategies for how departments adopt new procedures require clinical guidelines, a training program focused on competence, and a hospital education and privileging process for those acquiring new skills. LEVEL OF EVIDENCE: Therapeutic, level V.

Arterial waveform morphomics during hemorrhagic shock.

PURPOSE: The arterial pressure waveform is a composite of multiple interactions, and there may be more sensitive and specific features associated with hemorrhagic shock and intravascular volume depletion than systolic and/or diastolic blood pressure (BP) alone. The aim of this study was to characterize the arterial pressure waveform in differing grades of hemorrhage. METHODS: Ten anesthetized swine (70-90 kg) underwent a 40% controlled exponential hemorrhage. High-fidelity arterial waveform data were collected (500 Hz) and signal-processing techniques were used to extract key features. Regression modeling was used to assess the trend over time. Short-time Fourier transform (STFT) was utilized to assess waveform frequency and power spectrum density variance. RESULTS: All animals tolerated instrumentation and hemorrhage. The primary antegrade wave (P1) was relatively preserved while the renal (P2) and iliac (P3) reflection waves became noticeably attenuated during progressive hemorrhage. Several features mirrored changes in systolic and diastolic BP and plateaued at approximately 20% hemorrhage, and were best fit with non-linear sigmoidal regression modeling. The P1:P3 ratio continued to change during progressive hemorrhage (R2 = 0.51). Analysis of the first three harmonics during progressive hemorrhage via STFT demonstrated increasing variance with high coefficients of determination using linear regression in frequency (R2 = 0.70, 0.93, and 0.76, respectively) and power spectrum density (R2 = 0.90, 0.90, and 0.59, respectively). CONCLUSIONS: In this swine model of volume-controlled hemorrhage, hypotension was a predominating early feature. While most waveform features mirrored those of BP, specific features such as the variance may be able to distinguish differing magnitudes of hemorrhage despite little change in conventional measures.

A Surgical Endovascular Trauma Service Increases Case Volume and Decreases Time to Hemostasis.

OBJECTIVES: The aim of this study was to evaluate the effect of a recently active endovascular trauma service (ETS) on case volume and time to hemostasis, as a complement to an existing interventional radiology (IR) service. SUMMARY BACKGROUND DATA: Endovascular techniques are vital for trauma care, but timely access can be a challenge. There is a paucity of data on the effect of a multispecialty team for delivery of endovascular hemorrhage control. METHODS: The electronic medical record of trauma patients undergoing endovascular procedures between 2013 and 2018 was queried for provider type (IR or ETS). Case volume and rates were expressed per 100 monthly admissions, normalizing for seasonal variation. Interrupted time series analysis was used to model the case rate pre- and post-introduction of the ETS. Admission-to-procedure-time data were collected for pelvic angioembolization as a marker of patients requiring emergency hemostasis. RESULTS: During 6 years, 1274 admission episodes required endovascular interventions. Overall case volume increased from 2.7 to 3.6 at a rate of 0.006 (P = 0.734) after introduction of the ETS. IR case volume decreased from 3.3 to 2.6 at a rate of 0.03 (P = 0.063). ETS case volume increased at a rate of 0.048 (P < 0.001), which was significantly different from the IR trend (P < 0.001). Median (interquartile range) time-to-procedure (hours) was significantly shorter for pelvic angioembolization [3.0 (4.4) vs 4.3 (3.6); P < 0.001] when ETS was compared to IR. CONCLUSION: A surgical ETS increases case volume and decreases time to hemostasis for trauma patients requiring time sensitive interventions. Further work is required to assess patient outcome following this change.

Extended resuscitative endovascular balloon occlusion of the aorta (REBOA)-induced type 2 myocardial ischemia: a time-dependent penalty.

BACKGROUND: Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) increases cardiac-afterload and is used for patients in hemorrhagic shock. The cardiac tolerance of prolonged afterload augmentation in this context is unknown. The aim of this study is to quantify cardiac injury, if any, following 2, 3 and 4 hours of REBOA. METHODS: Anesthetized swine (70-90 kg) underwent a 40% controlled hemorrhage, followed by supraceliac resuscitative endovascular balloon occlusion of the aorta (REBOA) for 2 (n=5), 3 (n=5), and 4 hours (n=5). High-fidelity arterial wave form data were collected, and signal processing techniques were used to extract key inflection points. The adjusted augmentation index (AIx@75; augmentation pressure/pulse pressure, normalized for heart rate) was derived for use as a measure of aortic compliance (higher ratio = less compliance). Endpoints consisted of electrocardiographic, biochemical, and histologic markers of myocardial injury/ischemia. Regression modeling was used to assess the trend against time. RESULTS: All animals tolerated instrumentation, hemorrhage, and REBOA. The mean (±SD) systolic blood pressure (mm Hg) increased from 65±11 to 212±39 (p<0.001) during REBOA. The AIx@75 was significantly higher during REBOA than baseline, hemorrhage, and resuscitation phases (p<0.05). A time-dependent rise in troponin (R2=0.95; p<0.001) and T-wave deflection (R2=0.64; p<0.001) was observed. The maximum mean troponin (ng/mL) occurred at 4 hours (14.6±15.4) and maximum T-wave deflection (mm) at 65 minutes (3.0±1.8). All animals demonstrated histologic evidence of acute injury with increasing degrees of cellular myocardial injury. DISCUSSION: Prolonged REBOA may result in type 2 myocardial ischemia, which is time-dependent. This has important implications for patients where prolonged REBOA may be considered beneficial, and strategies to mitigate this effect require further investigation. LEVEL OF EVIDENCE: II.

Resuscitative endovascular balloon occlusion of the aorta for non-traumatic intra-abdominal hemorrhage.

BACKGROUND: Hemorrhagic shock is the second leading cause of death in blunt trauma and a significant cause of mortality in non-trauma patients. The increased use of resuscitative endovascular balloon occlusion of the aorta (REBOA) as a bridge to definitive control for massive hemorrhage has provided promising results in the trauma population. We describe an extension of this procedure to our hemodynamically unstable non-trauma patients. METHODS: This is a retrospective review of patients requiring REBOA for end stage non-traumatic abdominal hemorrhage from our tertiary care facility. After excluding patients with trauma, supradiaphragmatic bleed and thoracic/abdominal aortic aneurysms, demographics, etiology of bleed, REBOA placement specifics, complications and outcomes were reviewed. RESULTS: From August 2013 to August 2016, 11 patients were identified requiring REBOA placement for hemodynamic instability from non-traumatic abdominal hemorrhage. Average patient age was 54.9 (SD 15.2). Sixty-four percent suffered cardiac arrest prior to REBOA, with mean shock index of 1.29. Average time from diagnosis of shock (MAP ≤ 65) or signs of bleeding to placement of REBOA was 177 min. The leading etiologies of hemorrhage were ruptured visceral aneurysm and massive upper gastrointestinal bleed. REBOA was placed by both acute care and vascular surgeons. The procedure was mainly completed in the operating room in 82% of the patients and at the bedside in 18%. One patient expired before operative repair. Definitive surgical control of the source of bleeding was obtained by open surgical approach (n = 6) and combined surgical and endovascular approach (n = 4). In-hospital survival was 64%. There were no local complications related to REBOA placement. CONCLUSION: Similar to the trauma population, REBOA is an adjunctive technique for proximal control of bleeding as well as resuscitation in end stage non-traumatic intra-abdominal hemorrhage. We propose an algorithmic approach to REBOA use in this population and a larger prospective review is necessary to determine both the timing of REBOA placement and which non-traumatic patients may benefit from this technique. LEVEL OF EVIDENCE: V. STUDY TYPE: Brief report.

Aortic branch vessel flow during resuscitative endovascular balloon occlusion of the aorta.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a torso hemorrhage control adjunct. Aortic branch vessel flow (BVF) during REBOA is poorly characterized and has implications for ischemia-reperfusion injury. The aim of this study is to quantify BVF in hypovolemic shock with and without REBOA. METHODS: Female swine (79-90 kg) underwent anesthesia, 40% controlled hemorrhage and sonographic flow monitoring of the carotid, hepatic, superior mesenteric, renal, and femoral arteries. Animals were randomized to REBOA (n = 5) or no-REBOA (n = 5) for 4 hours, followed by full resuscitation and balloon deflation for 1 hour. RESULTS: All animals were successfully induced into hemorrhagic shock with a mean decrease of flow in all vessels of 50% from baseline (p < 0.001). Deployment of REBOA resulted in a 200% to 400% increase in carotid flow, but near complete abolition of BVF distal to the balloon. The no-REBOA group saw recovery of BVF to 100% of baseline in all measured vessels, except the hepatic at 50% to 75%. two-way analysis of variance confirmed a significant difference between the groups throughout the protocol (p < 0.001). During resuscitation, the REBOA group saw BVF restore to between 25% and 50%, but never achieving baseline values. The lactate at 4 hours was significantly higher in the REBOA versus no-REBOA group (17.2 ± 0.1 vs. 4.9 ± 1.4; p < 0.001). CONCLUSION: REBOA not only abolishing BVF during occlusion, but appears to have a post-REBOA effect, reducing visceral perfusion. This may be a source of REBOA associated ischemia-reperfusion injury and warrants further investigation in order to mitigate this effect.

Feasibility of basic transesophageal echocardiography in hemorrhagic shock: potential applications during resuscitative endovascular balloon occlusion of the aorta (REBOA).

BACKGROUND: There are numerous studies in the cardiovascular literature that have employed transesophageal echocardiography (TEE) in swine models, but data regarding the use of basic TEE in swine models is limited. The primary aim of this study is to describe an echocardiographic method that can be used with relative ease to qualitatively assess cardiovascular function in a porcine hemorrhagic shock model using resuscitative endovascular balloon occlusion of the aorta (REBOA). METHODS: Multiplane basic TEE exams were performed in 15 during an experimental hemorrhage model using REBOA. Cardiac anatomical structure and functional measurements were obtained. In a convenience sample (two animals from each group), advanced functional cardiovascular measurements were obtained before and after REBOA inflation for comparison with qualitative assessments. RESULTS: Basic TEE exams were performed in 15 swine. Appropriate REBOA placement was confirmed using TEE in all animals and verified with fluoroscopy. Left ventricular volume was decreased in all animals, and left ventricular systolic function increased following REBOA inflation. Right ventricular systolic function and volume remained normal prior to and after hemorrhage and REBOA use. Mean ejection fraction (EF) decreased from 64% (S.D. 9.6) to 62.1 (S.D. 16.8) after hemorrhage and REBOA inflation (p = 0.76); fractional area of change (FAC) decreased from 49.8 (S.D. 9.0) to 48.5 (S.D. 13.6) after hemorrhage and REBOA inflation (p = 0.82). CONCLUSION: Basic TEE, which requires less training than advanced TEE, may be employed by laboratory investigators and practitioners across a wide spectrum of experimental and clinical settings.

Life over Limb: Lower Extremity Ischemia in the Setting of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA).

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a temporizing maneuver used to decrease hemorrhage, and thus perfusion, below the level of aortic occlusion (AO). We sought to investigate lower extremity ischemia in patients who received REBOA. Between February 2013 and September 2016 patients at a tertiary center that received REBOA and survived more than six hours were enrolled. Thirty-one patients were identified, the mean ISS was 40 ± 14 and inhospital mortality was 39 per cent. Twenty received REBOA in zone 1 (distal thoracic aorta). Three (15%) developed lower extremity compartment syndrome (LECS) after zone 1 REBOA. Injury of iliofemoral arteries and veins was each associated with calf fasciotomies (both P = 0.005). A longer duration of AO at zone 1 was associated with calf and thigh fasciotomy (P = 0.046 and P = 0.048, respectively). Iliofemoral arterial injury was associated with thigh fasciotomy (P = 0.04). Eleven patients received REBOA in zone 3 (distal abdominal aorta). Five (45%) patients underwent fasciotomy; four (36%) due to LECS. Femoral arterial injury was associated with calf fasciotomies (P = 0.02). There was no association with sheath size or laterality and need for fasciotomy. Neither groin access for REBOA or AO solely caused limb loss or LECS. The contribution to distal ischemia by REBOA remains unclear in patients with lower extremity injury.

Resuscitative endovascular balloon occlusion of the aorta: rupture risk and implications for blind inflation.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a torso hemorrhage control technique. To expedite deployment, inflation is frequently performed as a blind technique with minimal imaging, which carries a theoretical risk of aortic injury. The objective of this study was to examine the relationship between balloon inflation, deformation and the risk of aortic rupture. METHODS: Compliant balloon catheters were incrementally inflated in segments of cadaveric swine aorta. Serial longitudinal and circumferential measurements were recorded, along with the incidence of aortic rupture. RESULTS: Fourteen cadaveric swine aorta segments were tested with mean (±SD) baseline aortic diameter (mm) of 14.2±3.4. Rupture occurred in three aortas. The mean baseline diameters (mm) of the aortic segments that were ruptured were significantly smaller than those that did not rupture (8.9±1.2 vs 15.6±1.9; P<0.001). The maximal circumferential stretch ratios were significantly higher in the aorta segments that ruptured compared with those that did not (1.9±0.1 vs 1.5±0.1; P<0.001). The maximal amount of balloon longitudinal deformation was 80 mm (116% longer than the intended working length). CONCLUSIONS: Inflation of aortic balloon catheters carries an inherent risk of aortic injury, which may be minimized through an understanding of the intrinsic characteristics of the aorta and compliant balloons. Smaller diameter aortic segments undergoing overinflation, particularly beyond a circumferential stretch ratio of 1.8, are at risk of aortic rupture. LEVEL OF EVIDENCE: Level II.

Patients' knowledge of potential pelvic floor changes associated with pregnancy and delivery.

Physicians cite pelvic floor injury as a major reason for Cesarean section as their personal preferred delivery mode. This study was undertaken to determine whether patients receive information about possible pelvic floor complications of pregnancy/delivery. Day 1 post-partum women completed a 52-item questionnaire assessing information given during routine antenatal care. Pelvic floor and general questions were intermixed. Of the 232 patients, the mean age was 26.9 years, with 59.5% white, 32.8% African-American and 7.7% other. Most (84.5%) had at least grade 12 education. The following percentage of patients reported receiving no information about: Kegel exercises 46.1%; episiotomy 51.3%; urinary incontinence 46.6%; fecal incontinence 80.6%; change in vaginal caliber 72.8%; neuropathy 84.9%. Counseling on all of these issues occurred significantly less frequently than education on general pregnancy topics. Our results suggest that knowledge and instruction of pelvic floor risks is very much lacking and provide us with an impetus to develop educational tools.