Venovenous extracorporeal membrane oxygenation in patients with traumatic brain injuries and severe respiratory failure: A single-center retrospective analysis.

BACKGROUND: Venovenous extracorporeal membrane oxygenation (VV ECMO) can support trauma patients with severe respiratory failure. Use in traumatic brain injury (TBI) may raise concerns of worsening complications from intracranial bleeding. However, VV ECMO can rapidly correct hypoxemia and hypercarbia, possibly preventing secondary brain injury. We hypothesize that adult trauma patients with TBI on VV ECMO have comparable survival with trauma patients without TBI. METHODS: A single-center, retrospective cohort study involving review of electronic medical records of trauma admissions between July 1, 2014, and August 30, 2022, with discharge diagnosis of TBI who were placed on VV ECMO during their hospital course was performed. RESULTS: Seventy-five trauma patients were treated with VV ECMO; 36 (48%) had TBI. Of those with TBI, 19 (53%) had a hemorrhagic component. Survival was similar between patients with and without a TBI (72% vs. 64%, p = 0.45). Traumatic brain injury survivors had a higher admission Glasgow Coma Scale (7 vs. 3, p < 0.001) than nonsurvivors. Evaluation of prognostic scoring systems on initial head computed tomography demonstrated that TBI VV ECMO survivors were more likely to have a Rotterdam score of 2 (62% vs. 20%, p = 0.03) and no survivors had a Marshall score of ≥4. Twenty-nine patients (81%) had a repeat head computed tomography on VV ECMO with one incidence of expanding hematoma and one new focus of bleeding. Neither patient with a new/worsening bleed received anticoagulation. Survivors demonstrated favorable neurologic outcomes at discharge and outpatient follow-up, based on their mean Rancho Los Amigos Scale (6.5; SD, 1.2), median Cerebral Performance Category (2; interquartile range, 1-2), and median Glasgow Outcome Scale-Extended (7.5; interquartile range, 7-8). CONCLUSION: In this series, the majority of TBI patients survived and had good neurologic outcomes despite a low admission Glasgow Coma Scale. Venovenous extracorporeal membrane oxygenation may minimize secondary brain injury and may be considered in select patients with TBI. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

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.

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.

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.

Traumatic cardiac arrest and resuscitative endovascular balloon occlusion of the aorta (REBOA): a preliminary analysis utilizing high fidelity invasive blood pressure recording and videography.

PURPOSE: Aortic occlusion (AO) increases proximal perfusion and may improve rates of return of spontaneous circulation (ROSC). The objective of this study was to investigate the hemodynamic effects of cardiopulmonary resuscitation (CPR) and AO by REBOA on patients in traumatic cardiac arrest. METHODS: Patients admitted between February 2013 and May 2017 at a tertiary center who suffered traumatic arrest, had an arterial line placed during resuscitation, and received CPR and REBOA which were included. In-hospital CPR data were obtained from videography. Arterial waveforms were recorded at 240 Hz. RESULTS: 11 consecutive patients were included, 82% male; mean (± SD) age 37 ± 19 years. 55% suffered blunt trauma and the remaining penetrating injuries. 64% arrested out of hospital. During compressions with AO, the mean systolic blood pressure (SBP) was 70 ± 22 mmHg, mean arterial pressure (MAP) 43 ± 19 mmHg, and diastolic blood pressure (DBP) 26 ± 17 mmHg. Nine (82%) had ROSC, with eight having multiple periods of ROSC and arrest in the initial period. In-hospital mortality was 82%. Cardiac ultrasonography was used during arrest in 73%. In two patients with arterial line data before and after AO, SBP (mmHg) improved from 51 to 73 and 55 to 96 during arrest after AO. CONCLUSIONS: High-quality chest compressions coupled with aortic occlusion may generate adequate perfusion pressures to increase the rate of ROSC. New technology capable of transducing central arterial pressure may help us to understand the effectiveness of CPR with and without aortic occlusion. REBOA may be a useful adjunct to high-quality chest compressions during arrest.

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.

Bringing Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) Closer to the Point of Injury.

BACKGROUND: The management of noncompressible torso hemorrhage remains a significant issue at the point of injury. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been used in the hospital to control bleeding and bridge patients to definitive surgery. Smaller delivery systems and wirefree devices may be used more easily at the point of injury by nonphysician providers. We investigated whether independent duty military medical technicians (IDMTs) could learn and perform REBOA correctly and rapidly as assessed by simulation. METHODS: US Air Force IDMTs without prior endovascular experience were included. All participants received didactic instruction and evaluation of technical skills. Procedural times and pretest/posttest examinations were administered after completion of all trials. The Likert scale was used to subjectively assess confidence before and after instruction. RESULTS: Eleven IDMTs were enrolled. There was a significant decrease in procedural times from trials 1 to 6. Overall procedural time (± standard deviation) decreased from 147.7 ± 27.4 seconds to 64 ± 8.9 seconds (ρ < .001). There was a mean improvement of 83.7 ± 24.6 seconds from the first to sixth trial (ρ < .001). All participants demonstrated correct placement of the sheath, measurement and placement of the catheter, and inflation of the balloon throughout all trials (100%). There was significant improvement in comprehension and knowledge between the pretest and posttest; average performance improved significantly from 36.4.6% ± 12.3% to 71.1% ± 8.5% (ρ < .001). Subjectively, all 11 participants noted significant improvement in confidence from 1.2 to 4.1 out of 5 on the Likert scale (ρ < .001). CONCLUSION: Technology for aortic occlusion has advanced to provide smaller, wirefree devices, making field deployment more feasible. IDMTs can learn the steps required for REBOA and perform the procedure accurately and rapidly, as assessed by simulation. Arterial access is a challenge in the ability to perform REBOA and should be a focus of further training to promote this procedure closer to the point of injury.

Assessment of Blood Flow Patterns Distal to Aortic Occlusion Using CT in Patients with Resuscitative Endovascular Balloon Occlusion of the Aorta.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is used to decrease hemorrhage below the level of aortic occlusion (AO); however, the amount of collateral blood flow below the level of occlusion is unknown. Our aim was to investigate blood flow patterns during complete AO in patients who underwent CT scan after REBOA. STUDY DESIGN: Between February 2013 and January 2017, patients who received REBOA and underwent CT scan with intravenous contrast during full AO were included. Patients were excluded if they had a CT scan performed with the balloon partially or fully deflated. RESULTS: Nine patients (8 men) were included; all had blunt trauma. Mean Injury Severity Score (±SD) was 48 ± 8 and mean age was 45 ± 19 years. Four had supra-celiac AO, and 5 had infra-renal AO. Arterial contrast enhancement was noted below the level of AO in all patients, and distal to REBOA sheath placement in 5. Collateralization from arteries above and below the AO was identified in all patients. Contrast extravasation distal to AO was identified in 4 patients, and hematomas in 8. Distal vascular enhancement patterns varied by level of AO and contrast administration site. CONCLUSIONS: Aortic occlusion appears to dramatically decrease, but does not completely impede, distal perfusion during REBOA due to multiple pathways of collateralization. Active extravasation and hematomas can still be detected in the setting of full AO, with purposefully timed contrast and image acquisition. Blood flow persists below the level of both the AO and in-dwelling sheath. Dynamic flow studies are needed to determine the contribution of AO and sheath placement to distal tissue ischemia.

The evolution of care improves outcome in blunt thoracic aortic injury: A Western Trauma Association multicenter study.

BACKGROUND: The management of blunt thoracic aortic injury (BTAI) has evolved radically in the last decade with changes in the processes of care and the introduction of thoracic endovascular aortic repair (TEVAR). These changes have wrought improved outcome, but the direct effect of TEVAR on outcome remains in question as previous studies have lacked vigorous risk adjustment and long-term follow-up. To address these knowledge gaps, we compared the outcomes of TEVAR, open surgical repair, and nonoperative management for BTAI. METHODS: Eight verified trauma centers recruited from the Western Trauma Association Multicenter Study Group retrospectively studied all patients with BTAI admitted between January 1, 2006, and June 30, 2016. Data included demographics, comorbidities, admitting physiology, injury severity, in-hospital care, and outcome. RESULTS: We studied 316 patients with BTAI; 57 (18.0%) were in extremis and died before treatment. Of the 259 treated surgically, TEVAR was performed in 176 (68.0%), open in 28 (10.8%), hybrid in 4 (1.5%), and nonoperative in 51 (19.7%). Thoracic endovascular aortic repair and open repair groups had similar Injury Severity Scale score, chest Abbreviated Injury Scale score, Trauma and Injury Severity Score, and probability of survival, but differed in median age (open: 28 [interquartile range {IQR}, 19-51]; TEVAR: 46 [IQR, 28-60]; p < 0.007), zone of aortic injury (p < 0.001), and grade of aortic injury (open: 6 [IQR, 4-6]; TEVAR: 2 [IQR, 2-4]; p < 0.001). The overall in-hospital mortality was 6.6% (TEVAR: 5.7%, open: 10.7%, nonoperative: 3.9%; p = 0.535). Of the 240 patients who survived to discharge, two died (one at 9 months and one at 8 years); both were managed with TEVAR, but the deaths were unrelated to the aortic procedure. Stent graft surveillance computed tomography scans were not obtained in 37.6%. CONCLUSIONS: The mortality of BTAI continues to decrease. Thoracic endovascular aortic repair, when anatomically suitable, should be the treatment of choice. Open repair remains necessary for more proximal injuries. Process improvement in computed tomography imaging in follow-up of TEVAR is warranted. LEVEL OF EVIDENCE: Therapeutic/care management, level III.

Resuscitative Endovascular Balloon Occlusion of the Aorta: Pushing Care Forward.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA), used to temporize noncompressible and junctional hemorrhage, may be deployable to the forward environment. Our hypothesis was that nonsurgeon physicians and high-level military medical technicians would be able to learn the theory and insertion of REBOA. METHODS: US Army Special Operations Command medical personnel without prior endovascular experience were included. All participants received didactic instruction of the Basic Endovascular Skills for Trauma Course™ together, with individual evaluation of technical skills. A pretest and a posttest were administered to assess comprehension. RESULTS: Four members of US Army Special Operations Command-two nonsurgeon physicians, one physician assistant, and one Special Operations Combat Medic-were included. REBOA procedural times moving from trial 1 to trial 6 decreased significantly from 186 ± 18.7 seconds to 83 ± 10.3 seconds (ρ < .0001). All participants demonstrated safe REBOA insertion and verbalized the indications for REBOA insertion and removal through all trials. All five procedural tasks were performed correctly by each participant. Comprehension and knowledge between the pretest and posttest improved significantly from 67.6 ± 7.3% to 81.3 ± 8.1% (ρ = .039). CONCLUSION: This study demonstrates that nonsurgeon and nonphysician providers can learn the steps required for REBOA after arterial access is established. Although insertion is relatively straightforward, the inability to gain arterial access percutaneously is prohibitive in providers without a surgical skillset and should be the focus of further training.

Smaller introducer sheaths for REBOA may be associated with fewer complications.

INTRODUCTION: Large arterial sheaths currently used for resuscitative endovascular balloon occlusion of the aorta (REBOA) may be associated with severe complications. Smaller diameter catheters compatible with 7Fr sheaths may improve the safety profile. METHODS: A retrospective review of patients receiving REBOA through a 7Fr sheath for refractory traumatic hemorrhagic shock was performed from January 2014 to June 2015 at five tertiary-care hospitals in Japan. Demographics were collected including method of arterial access; outcomes included mortality and REBOA-related access complications. RESULTS: Thirty-three patients underwent REBOA at Zone 1 (level of the diaphragm). Most patients were male (70%), with a mean age (+SD) 50 ± 18 years, mean BMI 23 ± 4, and a median [IQR] ISS of 38 [34, 52]. Ninety-four percent of patients presented after sustaining injuries from blunt mechanisms. Twenty-four percent underwent CPR before arrival, and an additional 15% received CPR after admission. Percutaneous arterial access without ultrasound or fluoroscopy was achieved in all patients. Systolic blood pressure increased significantly following balloon occlusion (mean 62 ± 36 to 106 ± 40 mm Hg, p < 0.001). Median total duration of complete initial occlusion was 26 [range 10-35] minutes. Sixteen patients (49%) survived beyond 24 hours, and 14 patients (42%) survived beyond 30 days. Twenty-four-hour and 30-day survival were 48% and 42%, respectively. Of the patients surviving 24 hours (n = 16), median duration of sheath placement was 28 [range 18-45] hours with all removed using manual pressure to achieve hemostasis. Of 33 REBOAs, 20 were performed by Emergency Medicine practitioners, 10 by Emergency Medicine practitioners with endovascular training, and 3 by Interventional Radiologists. No complication related to sheath insertion or removal was identified during the follow-up period, including dissection, pseudoaneurysm, retroperitoneal hematoma, leg ischemia, or distal embolism. CONCLUSIONS: 7Fr REBOA catheters can significantly elevate systolic blood pressure with no access-related complications. Our results suggest that a 7Fr introducer device for REBOA may be a safe and effective alternative to large-bore sheaths, and may remain in place during the post-procedure resuscitative phase without sequelae. LEVEL OF EVIDENCE: Therapeutic/care management, level V.

Holmium:YAG laser bronchoscopy ablation of benign and malignant airway obstructions: an 8-year experience.

Patients suffering from severe tracheobronchial obstruction are vulnerable to dyspnea, respiratory failure, obstructive pneumonia, and death. Treatment with a holmium:YAG laser, an alternative to the neodymium:YAG laser, may provide symptomatic relief. This is the largest case series to date describing the application of the holmium:YAG laser via bronchoscopy for benign and malignant obstructive disease. The data were retrospectively collected from 99 patients, with either benign or malignant tracheobronchial obstruction, who underwent 261 interventional bronchoscopy procedures in the operating room with laser ablation between January 2004 and November 2011. Categorical variables were analyzed with the chi-square and Fisher's exact tests as appropriate in contingency tables, whereas Student's t-test was performed for comparison of continuous variables. Patient follow-up was concluded on September 15, 2013. The holmium:YAG laser was used in 261 procedures performed on 99 patients with either benign or malignant disease. Symptomatic improvement was demonstrated in 90 % of all benign etiology cases and 77 % of all malignant etiology cases. Within the benign and malignant subgroups, improvement was dependent on anatomical location rather than etiology of the lesion. Complications occurred in 2.3 % of the procedures, with mortality in less than 1 % of procedures. Results confirm the usefulness and safety of the holmium:YAG laser in the treatment of patients with severe benign and malignant obstructive tracheobronchial obstructions. The holmium:YAG laser is an appealing alternative to the neodymium:YAG laser.