Mind the GAHP: A novel protocol for improved vascular access in the hypotensive patient.

Background: Obtaining intravenous access in hypotensive patients is challenging and may critically delay resuscitation. The Graduated Vascular Access for Hypotensive Patient (GAHP) protocol leverages intraosseous fluid boluses to specifically dilate proximal veins. This study aims to evaluate the efficacy of GAHP in maximizing venous targets through early distal intraosseous access and a small fluid bolus. Methods: This was a prospective randomized cadaveric pilot study to evaluate extremity venous engorgement during intraosseous infusion. Cadavers (n = 23) had an intraosseous needle inserted into four sites: distal radius, proximal humerus, distal femur, and distal tibia. Intraosseous saline was rapidly infused, venous optimization was measured using real-time ultrasound. Primary outcome was maximum vessel circumference increase with intraosseous infusion. Secondary outcomes were: time to maximum circumference, and infusion volume required. Statistical analyses included Levene's test for equality of variances, Wilcoxon signed-rank test, and generalized estimating equation. Results: There was a significant mean increase of 1.03 cm (95% CI 0.86, 1.20), representing a difference of 102%. We found no significant difference in time to optimize vessel circumference across sites, but volume required significantly differed. Conclusion: GAHP quickly and effectively increased the circumference of anatomically adjacent veins. Anatomical sites did not differ on time to reach maximum enlargement of vessels following intraosseous infusion but did differ in terms of volume required to maximize vessel circumference. Further research is needed using live, hypotensive patients.

Limitations of Triage in Military Mass Casualty Response: A Case Series.

INTRODUCTION: Mass casualty events (MASCALs) in the combat environment, which involve large numbers of casualties that overwhelm immediately available resources, are fundamentally chaotic and dynamic and inherently dangerous. Formal triage systems use diagnostic algorithms, colored markers, and four or more named categories. We hypothesized that formal triage systems are inadequately trained and practiced and too complex to successfully implement in true MASCAL events. This retrospective analysis evaluates the real-world application of triage systems in prehospital military MASCALs and other aspects of MASCAL management. METHODS: We surveyed Special Operations Forces (SOF) medics known to us who have participated in military prehospital MASCALs and analyzed them. Aggregated data describing the scope of the incidents, the use of formal triage algorithms and colored markers, the number of categories, and the interventions on scene were analyzed using descriptive statistics, and lessons learned were consolidated. RESULTS: From 1996 to 2022 we identified 29 MASCALs that were managed by military medics in the prehospital setting. There was a median of three providers (range 1-85) and 15 casualties (range 6-519) per event. Four or more formal triage categories were used in only one event. Colored markers and formal algorithms were not used. Life-saving interventions were performed in 27 of 29 (93%) missions and blood transfusions were performed in four (17%) MASCALs. The top lessons learned were: 1) security and accountability are cornerstones of MASCAL management; 2) casualty movement is a priority; 3) intuitive triage categories are the default; 4) life-saving interventions are performed as time and tactics permit. CONCLUSION: Formal triage systems requiring the use of diagnostic algorithms, colored tags, and four or five categories are seldom implemented in real-world military prehospital MASCAL management. The training of field triage should be simplified and pragmatic, as exemplified by these instances.

Lessons Learned From a Large-Scale Military Mass Casualty Incident: Reevaluation of the Response to the Khobar Towers Bombing.

The 1996 Khobar Towers bombing, a large-scale mass casualty incident (MASCAL) at a coalition forces housing complex, resulted in 519 casualties. Key lessons learned include the importance of MASCAL exercises, self-aid and buddy care, and casualty triage, all critical to preparation for future terrorist attacks or near-peer combat operations MASCALs.

Screening Performance of S100 Calcium-Binding Protein B, Glial Fibrillary Acidic Protein, and Ubiquitin C-Terminal Hydrolase L1 for Intracranial Injury Within Six Hours of Injury and Beyond.

The Scandinavian NeuroTrauma Committee (SNC) guidelines recommend S100 calcium-binding protein B (S100B) as a screening tool for early detection of Traumatic brain injury (TBI) in patients presenting with an initial Glasgow Coma Scale (GCS) of 14-15. The objective of the current study was to compare S100B's diagnostic performance within the recommended 6-h window after injury, compared with glial fibrillary acidic protein (GFAP) and UCH-L1. The secondary outcome of interest was the ability of these biomarkers in detecting traumatic intracranial pathology beyond the 6-h mark. The Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) core database (2014-2017) was queried for data pertaining to all TBI patients with an initial GCS of 14-15 who had a blood sample taken within 6 h of injury in which the levels of S100B, GFAP, and UCH-L1 were measured. As a subgroup analysis, data involving patients with blood samples taken within 6-9 h and 9-12 h were analyzed separately for diagnostic ability. The diagnostic ability of these biomarkers for detecting any intracranial injury was evaluated based on the area under the receiver operating characteristic curve (AUC). Each biomarker's sensitivity, specificity, and accuracy were also reported at the cutoff that maximized Youden's index. A total of 531 TBI patients with GCS 14-15 on admission had a blood sample taken within 6 h, of whom 24.9% (n = 132) had radiologically confirmed intracranial injury. The AUCs of GFAP (0.86, 95% confidence interval [CI]: 0.82-0.90) and UCH-L1 (0.81, 95% CI: 0.76-0.85) were statistically significantly higher than that of S100B (0.74, 95% CI: 0.69-0.79) during this time. There was no statistically significant difference in the predictive ability of S100B when sampled within 6 h, 6-9 h, and 9-12 h of injury, as the p values were >0.05 when comparing the AUCs. Overlapping AUC 95% CI suggests no benefit of a combined GFAP and UCH-L1 screening tool over GFAP during the time periods studied [0.87 (0.83-0.90) vs. 0.86 (0.82-0.90) when sampled within 6 h of injury, 0.83 (0.78-0.88) vs. 0.83 (0.78-0.89) within 6 to 9 h and 0.81 (0.73-0.88) vs. 0.79 (0.72-0.87) within 9-12 h]. Targeted analysis of the CENTER-TBI core database, with focus on the patient category for which biomarker testing is recommended by the SNC guidelines, revealed that GFAP and UCH-L1 perform superior to S100B in predicting CT-positive intracranial lesions within 6 h of injury. GFAP continued to exhibit superior predictive ability to S100B during the time periods studied. S100B displayed relatively unaltered screening performance beyond the diagnostic timeline provided by SNC guidelines. These findings suggest the need for a reevaluation of the current SNC TBI guidelines.

Sclerosing encapsulating peritonitis: A rare cause of small bowel obstruction.

INTRODUCTION: Sclerosing encapsulating peritonitis (SEP), also known as abdominal cocoon syndrome, represents a rare cause of small bowel obstruction. CASE PRESENTATION: Herein we report an uncommon case of small bowel obstruction caused by SEP in a 30-year-old male with no prior surgical history who presented to the emergency department. The patient was diagnosed with SEP on preoperative CT scan and underwent a therapeutic laparotomy with extensive adhesiolysis. His symptoms resolved postoperatively and he was discharged in a good condition. DISCUSSION: Sclerosing encapsulating peritonitis is more prevalent in men, and has a higher incidence in tropical and subtropical countries. The exact pathophysiology of the disease in not well understood, but subclinical intra-abdominal inflammation is theorized to result in a thick fibrocollagenous membrane encapsulating intra-peritoneal organs which leads to intestinal obstruction. The disease is categorized into primary and secondary SEP depending on identification of a pathologic factor. It is further divided into 3 sub-types according to the extent of the peritoneal membrane encasement observed intra-operatively. Patients often present with recurrent history of small bowel obstruction in the absence of prior abdominal surgery. Computed tomography of the abdomen with experienced radiologist interpretation can aid in preoperative diagnosis. In patients with recurrent obstructions and failure of non-operative management, surgical adhesiolysis remains the gold standard. CONCLUSION: Sclerosing encapsulating peritonitis, is a rare cause of small bowel obstruction. The exact pathogenesis is not well understood. The main line of treatment is surgical adhesiolysis and excision of the intra-abdominal fibrocollagenous membrane.

A 21-Year-Old Man with Previous History of Gastrectomy, Cholecystectomy, and Biliary Stenting with Failed Non-Operative Management of Blunt Trauma to the Liver Due to Traumatic Stent Perforation.

BACKGROUND Conservative management of blunt trauma to the liver is commonly used when there are no immediate signs of rupture or hemorrhage, but requires patient monitoring. The rate of failure for non-operative management ranges is 3-15%. This report is of a 21-year-old man with a previous history of gastrectomy, cholecystectomy, and biliary stenting with failed non-operative management of blunt trauma to the liver following a motor vehicle crash, due to traumatic stent perforation. CASE REPORT The patient reported abdominal pain and had positive FAST for fluid in the hepatorenal space. CT abdomen showed grade 3 hepatic injury and a common bile duct stent. He was resuscitated and admitted to the ICU. He developed escalating abdominal pain and tachycardia without hypotension. Repeat CT demonstrated a paraduodenal gas bubble. He underwent exploratory laparotomy, during which the following were found: hemoperitoneum, no active bleeding, a 3-cm blue stent exiting the left hepatic duct surrounded by a fibrous tract, and bile spilling from around the stent. The protruding portion of the stent was resected, the was tract oversewn, and the abdomen was closed. Once stabilized, the patient underwent ERCP with removal of the remaining stent segment. The postoperative course was complicated by surgical wound infection and fascial dehiscence managed operatively and with local wound care, and deep-space infections managed by interventional radiology drainage. CONCLUSIONS Blunt trauma injury of the liver can be successfully managed conservatively. However, this case highlights the importance of knowledge of the patient's medical history and the presence of biliary stents, which can result in traumatic biliary perforation with an intact liver.

Hypertonic Saline for Severe Traumatic Brain Injury With Herniation: A Military Prehospital Case Report.

Severe traumatic brain injury (sTBI) is a devastating injury with limited prehospital therapies available. The Joint Trauma System (JTS) Clinical Practice Guidelines recommend hypertonic saline (HTS) for casualties with sTBI and signs of impending or ongoing herniation (IOH), but its use by combat medics has never been reported in the literature. This report details the management of a pregnant patient with sTBI and signs of IOH, including the use of HTS, by US Air Force pararescumen in an austere prehospital setting. Treatment with HTS was followed by improvement in the patient's neurologic exam and successful evacuation to definitive care where her child was delivered alive. Additionally, we review the pathophysiology and signs of herniation, the mechanism of action of hyperosmotic therapies, and the rationale behind the use of HTS in the combat setting.

Austere Fasciotomy: Alternative Equipment for Performance in the Field.

BACKGROUND: Acute compartment syndrome (ACS) following extremity trauma requires rapid fasciotomy to avoid significant morbidity and limb loss. Four-compartment fasciotomy of the leg is a surgical procedure typically performed in the operating room; however, casualties who cannot be rapidly transported may need fasciotomies in the prehospital setting. In the absence of traditional operating instruments (e.g., scalpel, long Metzenbaum scissors, electrocautery), alternative means of fasciotomy may be needed. We undertook a proof-of-concept study using cadaver models to determine whether leg fasciotomies could be performed with alternative devices compared with the surgical standard. METHODS: Two-incision, four-compartment fasciotomies were performed on fresh, never-frozen, non-embalmed cadaver legs using a scalpel for the initial skin incision, followed by release of the fascia using one of the following instruments: 5.5-in curved Mayo scissors; Benchmade rescue hook (model BM-5BLKW); rescue hook on the Leatherman Raptor multitool (model 831741-FFP); Leatherman Z-Rex multitool rescue hook (model LM93408); or No. 10 PenBlade (model PB-M-10- CAS). The procedures were performed by a surgeon. Skin and fascia incisional lengths were recorded along with a subjective impression of the performance for each device. Post-procedural dissection was performed to identify associated injuries to the muscle, superficial peroneal nerve, and the greater saphenous vein (GSV). RESULTS: All devices were able to adequately release the fascia in all four compartments. All rescue hooks (Benchmade, Raptor, and Z-Rex) required a "pull technique" and a skin incision of equal length to the fascia incision. The PenBlade was used in a "push technique," similar to the standard scissor fasciotomy through a smaller skin incision. There was one superficial peroneal nerve transection with the rescue hooks, but there were no GSV injuries or significant muscle damage with any instrument. CONCLUSION: Four-compartment fasciotomy can be performed with readily available alternative equipment such as rescue hooks and the PenBlade. Hook-type devices require longer skin incisions compared with scissors and the PenBlade. In contested environments, patients with ACS may require fasciotomy prior to evacuation to surgical teams; training combat medics in the use of these alternative instruments in the field may preserve life and limb.

Nephrectomy After High-Grade Renal Trauma is Associated With Higher Mortality: Results From the Multi-Institutional Genitourinary Trauma Study (MiGUTS).

OBJECTIVE: To test the hypothesis that undergoing nephrectomy after high-grade renal trauma is associated with higher mortality rates. METHODS: We gathered data from 21 Level-1 trauma centers through the Multi-institutional Genito-Urinary Trauma Study. Patients with high-grade renal trauma were included. We assessed the association between nephrectomy and mortality in all patients and in subgroups of patients after excluding those who died within 24 hours of hospital arrival and those with GCS≤8. We controlled for age, injury severity score (ISS), shock (systolic blood pressure <90 mmHg), and Glasgow Coma Scale (GCS). RESULTS: A total of 1181 high-grade renal trauma patients were included. Median age was 31 and trauma mechanism was blunt in 78%. Injuries were graded as III, IV, and V in 55%, 34%, and 11%, respectively. There were 96 (8%) mortalities and 129 (11%) nephrectomies. Mortality was higher in the nephrectomy group (21.7% vs 6.5%, P <.001). Those who died were older, had higher ISS, lower GCS, and higher rates of shock. After adjusting for patient and injury characteristics nephrectomy was still associated with higher risk of death (RR: 2.12, 95% CI: 1.26-2.55). CONCLUSION: Nephrectomy was associated with higher mortality in the acute trauma setting even when controlling for shock, overall injury severity, and head injury. These results may have implications in decision making in acute trauma management for patients not in extremis from renal hemorrhage.

23.4% Hypertonic Saline: A Tactical Option for the Management of Severe Traumatic Brain Injury With Impending or Ongoing Herniation.

There are limited options available to the combat medic for management of traumatic brain injury (TBI) with impending or ongoing herniation. Current pararescue and Tactical Combat Casualty Care (TCCC) guidelines prescribe a bolus of 3% or 5% hypertonic saline. However, this fluid bears a tactical burden of weight (~570g) and pack volume (~500cm3). Thus, 23.4% hypertonic saline is an attractive option, because it has a lighter weight (80g) and pack volume (55cm3), and it provides a similar osmotic load per dose. Current literature supports the use of 23.4% hypertonic saline in the management of acute TBI, and evidence indicates that it is safe to administer via peripheral and intraosseous cannulas. Current combat medic TBI treatment algorithms should be updated to include the use of 23.4% hypertonic saline as an alternative to 3% and 5% solutions, given its effectiveness and tactical advantages.

A Case Series of Air Force Pararescue Long-Range Ocean Rescues.

BACKGROUND: US Air Force (USAF) pararescuemen (PJs) perform long-range ocean rescue missions for ill or injured civilians when advanced care and transport are not available. The purpose of this case series is to examine the details of these missions, review patient treatments and outcomes, and describe common tactics, techniques, and procedures for these missions. METHODS: Cases in which the USAF PJs preformed long-range ocean rescue for critically ill or injured civilians between 2011 and 2018 were identified. Case information was obtained, including patient demographics, location, infiltration/exfiltration methods, diagnoses, treatments, duration of patient care, patient outcome, and lessons learned. RESULTS: A total of 14 pararescue missions involving 22 civilians were identified for analysis. Of the 22 patients, 10 (45%) suffered burns, six (27%) had abdominal issues, four (18%) had musculoskeletal injuries, one had a traumatic brain injury, and one had a necrotizing soft-tissue infection. Medical care of these patients included intravenous fluid and blood product resuscitation, antibiotics, analgesics, airway management, and escharotomy. The median duration of patient care was 51 hours. CONCLUSION: This case series illustrates the complex transportation requirements, patient and gear logistical challenges, austere medicine, and prolonged field care (PFC) unique to USAF PJ open-water response.

Management of Critically Injured Burn Patients During an Open Ocean Parachute Rescue Mission.

Best practices and training for prolonged field care (PFC) are evolving. The New York Pararescue Team has used part task training, cadaver labs, clinical rotations, and a complicated sim lab to prepare for PFC missions including critical care. This report details an Atlantic Ocean nighttime parachute insertion to provide advanced burn care to two sailors with 50% and 60% body surface area burns. Medical mission planning included pack-out of ventilators, video laryngoscopes, medications, and 50 L of lactated Ringer's (LR). Over the course of 37 hours, the patients required high-volume resuscitation, analgesia, wound care, escharotomies, advanced airway and ventilator management, continuous sedation, telemedicine consultation, and complicated patient movement during evacuation. A debrief survey was obtained from the Operators highlighting recommendation for more clinical rotations and labs, missionspecific pack-outs, and tactical adjustments. This historic mission represents the most sophisticated PFC ever performed by PJs and serves to validate and share our approach to PFC.

Subcutaneous Perforation of Recurrent Gastric Fistula After Abdominoplasty with Scar Revision.

This case represents an unusual, and previously unreported, complication of delayed leakage of gastric contents into the subcutaneous tissues 2 years after division of a gastrostomy tube tract during abdominoplasty. Our patient required urgent exploration for contamination control and closure of the fistula and recovered fully. Persistent gastrocutaneous fistula is uncommon in adults and even less common is recannulization of a fistula track after initial closure. A thorough review of operative history and comparison to previous imaging were crucial for appropriate diagnosis and operative planning. Formal closure of gastrostomy tube sites during scar revision and abdominoplasty may help prevent the complication of delayed gastrostomy tube tract rupture into the subcutaneous tissues.

Current Management of Extraperitoneal Bladder Injuries: Results from the Multi-Institutional Genito-Urinary Trauma Study (MiGUTS).

PURPOSE: We studied the current management trends for extraperitoneal bladder injuries and evaluated the use of operative repair versus catheter drainage, and the associated complications with each approach. MATERIALS AND METHODS: We prospectively collected data on bladder trauma from 20 level 1 trauma centers across the United States from 2013 to 2018. We excluded patients with intraperitoneal bladder injury and those who died within 24 hours of hospital arrival. We separated patients with extraperitoneal bladder injuries into 2 groups (catheter drainage vs operative repair) based on their initial management within the first 4 days and compared the rates of bladder injury related complications among them. Regression analyses were used to identify potential predictors of complications. RESULTS: From 323 bladder injuries we included 157 patients with extraperitoneal bladder injuries. Concomitant injuries occurred in 139 (88%) patients with pelvic fracture seen in 79%. Sixty-seven patients (43%) initially underwent operative repair for their extraperitoneal bladder injuries. The 3 most common reasons for operative repair were severity of injury or bladder neck injury (40%), injury found during laparotomy (39%) and concern for pelvic hardware contamination (28%). Significant complications were identified in 23% and 19% of the catheter drainage and operative repair groups, respectively (p=0.55). The only statistically significant predictor for complications was bladder neck or urethral injury (RR 2.69, 95% 1.21-5.97, p=0.01). CONCLUSIONS: In this large multi-institutional cohort, 43% of patients underwent surgical repair for initial management of extraperitoneal bladder injuries. We found no significant difference in complications between the initial management strategies of catheter drainage and operative repair. The most significant predictor for complications was concomitant urethral or bladder neck injury.

The American Association for the Surgery of Trauma renal injury grading scale: Implications of the 2018 revisions for injury reclassification and predicting bleeding interventions.

BACKGROUND: In 2018, the American Association for the Surgery of Trauma (AAST) published revisions to the renal injury grading system to reflect the increased reliance on computed tomography scans and non-operative management of high-grade renal trauma (HGRT). We aimed to evaluate how these revisions will change the grading of HGRT and if it outperforms the original 1989 grading in predicting bleeding control interventions. METHODS: Data on HGRT were collected from 14 Level-1 trauma centers from 2014 to 2017. Patients with initial computed tomography scans were included. Two radiologists reviewed the scans to regrade the injuries according to the 1989 and 2018 AAST grading systems. Descriptive statistics were used to assess grade reclassifications. Mixed-effect multivariable logistic regression was used to measure the predictive ability of each grading system. The areas under the curves were compared. RESULTS: Of the 322 injuries included, 27.0% were upgraded, 3.4% were downgraded, and 69.5% remained unchanged. Of the injuries graded as III or lower using the 1989 AAST, 33.5% were upgraded to grade IV using the 2018 AAST. Of the grade V injuries, 58.8% were downgraded using the 2018 AAST. There was no statistically significant difference in the overall areas under the curves between the 2018 and 1989 AAST grading system for predicting bleeding interventions (0.72 vs. 0.68, p = 0.34). CONCLUSION: About one third of the injuries previously classified as grade III will be upgraded to grade IV using the 2018 AAST, which adds to the heterogeneity of grade IV injuries. Although the 2018 AAST grading provides more anatomic details on injury patterns and includes important radiologic findings, it did not outperform the 1989 AAST grading in predicting bleeding interventions. LEVEL OF EVIDENCE: Prognostic and Epidemiological Study, level III.

Pharmacokinetics of Tranexamic Acid Given as an Intramuscular Injection Compared to Intravenous Infusion in a Swine Model of Ongoing Hemorrhage.

INTRODUCTION: Tranexamic acid (TXA) improves survival in traumatic hemorrhage, but difficulty obtaining intravenous (IV) access may limit its use in austere environments, given its incompatibility with blood products. The bioavailability of intramuscular (IM) TXA in a shock state is unknown. We hypothesized that IM and IV administration have similar pharmacokinetics and ability to reverse in vitro hyperfibrinolysis in a swine-controlled hemorrhage model. METHODS: Twelve Yorkshire cross swine were anesthetized, instrumented, and subjected to a 35% controlled hemorrhage, followed by resuscitation. During hemorrhage, they were randomized to receive a 1 g IV TXA infusion over 10 min, 1 g IM TXA in two 5 mL injections, or 10 mL normal saline IM injection as a placebo group to assess model adequacy. Serum TXA concentrations were determined using liquid chromatography-mass spectrometry, and plasma samples supplemented with tissue plasminogen activator (tPA) were analyzed by rotational thromboelastometry. RESULTS: All animals achieved class III shock. There was no difference in the concentration-time areas under the curve between TXA given by either route. The absolute bioavailability of IM TXA was 97%. IV TXA resulted in a higher peak serum concentration during the infusion, with no subsequent differences. Both IV and IM TXA administration caused complete reversal of in vitro tPA-induced hyperfibrinolysis. CONCLUSION: The pharmacokinetics of IM TXA were similar to IV TXA during hemorrhagic shock in our swine model. IV administration resulted in a higher serum concentration only during the infusion, but all levels were able to successfully correct in vitro hyperfibrinolysis. There was no difference in total body exposure to equal doses of TXA between the two routes of administration. IM TXA may prove beneficial in scenarios where difficulty establishing dedicated IV access could otherwise limit or delay its use.

Renal effects of three endoaortic occlusion strategies in a swine model of hemorrhagic shock.

INTRODUCTION: Trauma patients are predisposed to kidney injury. We hypothesized that in shock, zone 3 REBOA would increase renal blood flow (RBF) compared to control and that a period of zone 3 occlusion following zone 1 occlusion would improve renal function compared to zone 1 occlusion alone. MATERIALS AND METHODS: Twenty-four anesthetized swine underwent hemorrhagic shock, 45 min of zone 1 REBOA (Z1, supraceliac), zone 3 REBOA (Z3, infrarenal), or no intervention (control) followed by resuscitation with shed blood and 5 h of critical care. In a fourth group (Z1Z3), animals underwent 55 min of zone 3 REBOA following zone 1 occlusion. Physiologic parameters were recorded, blood and urine were collected at specified intervals. RESULTS: During critical care, there were no differences in RBF between the Z1 and Z3 groups. The average RBF during critical care in Z1Z3 was significantly lower than in Z3 alone (98.2 ±â€¯23.9 and 191.9 ±â€¯23.7 mL/min; p = 0.046) and not different than Z1. There was no difference in urinary neutrophil gelatinase-associated lipocalin-to-urinary creatinine ratio between Z1 and Z1Z3. Animals in the Z1Z3 group had a significant increase in the ratio at the end of the experiment compared to baseline [median (IQR)] [9.2 (8.2-13.2) versus 264.5 (73.6-1174.6)]. Following Z1 balloon deflation, RBF required 45 min to return to baseline. CONCLUSION: Neither zone 3 REBOA alone nor zone 3 REBOA following zone 1 REBOA improved renal blood flow or function. Following zone 1 occlusion, RBF is restored to baseline levels after approximately 45 min.

Resuscitative Endovascular Balloon Occlusion of the Aorta: Review of the Literature and Applications to Veterinary Emergency and Critical Care.

While hemorrhagic shock might be the result of various conditions, hemorrhage control and resuscitation are the corner stone of patient management. Hemorrhage control can prove challenging in both the acute care and surgical settings, especially in the abdomen, where no direct pressure can be applied onto the source of bleeding. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as a promising replacement to resuscitative thoracotomy (RT) for the management of non-compressible torso hemorrhage in human trauma patients. By inflating a balloon at specific levels (or zones) of the aorta to interrupt blood flow, hemorrhage below the level of the balloon can be controlled. While REBOA allows for hemorrhage control and augmentation of blood pressure cranial to the balloon, it also exposes caudal tissue beds to ischemia and the whole body to reperfusion injury. We aim to introduce the advantages of REBOA while reviewing known limitations. This review outlines a step-by-step approach to REBOA implementation, and discusses common challenges observed both in human patients and during translational large animal studies. Currently accepted and debated indications for REBOA in humans are discussed. Finally, we review possible applications for veterinary patients and how REBOA has the potential to be translated into clinical veterinary practice.

The associations between initial radiographic findings and interventions for renal hemorrhage after high-grade renal trauma: Results from the Multi-Institutional Genitourinary Trauma Study.

BACKGROUND: Indications for intervention after high-grade renal trauma (HGRT) remain poorly defined. Certain radiographic findings can be used to guide the management of HGRT. We aimed to assess the associations between initial radiographic findings and interventions for hemorrhage after HGRT and to determine hematoma and laceration sizes predicting interventions. METHODS: The Genitourinary Trauma Study is a multicenter study including HGRT patients from 14 Level I trauma centers from 2014 to 2017. Admission computed tomography scans were categorized based on multiple variables, including vascular contrast extravasation (VCE), hematoma rim distance (HRD), and size of the deepest laceration. Renal bleeding interventions included angioembolization, surgical packing, renorrhaphy, partial nephrectomy, and nephrectomy. Mixed-effect Poisson regression was used to assess the associations. Receiver operating characteristic analysis was used to define optimal cutoffs for HRD and laceration size. RESULTS: In the 326 patients, injury mechanism was blunt in 81%. Forty-seven (14%) patients underwent 51 bleeding interventions, including 19 renal angioembolizations, 16 nephrectomies, and 16 other procedures. In univariable analysis, presence of VCE was associated with a 5.9-fold increase in risk of interventions, and each centimeter increase in HRD was associated with 30% increase in risk of bleeding interventions. An HRD of 3.5 cm or greater and renal laceration depth of 2.5 cm or greater were most predictive of interventions. In multivariable models, VCE and HRD were significantly associated with bleeding interventions. CONCLUSION: Our findings support the importance of certain radiographic findings in prediction of bleeding interventions after HGRT. These factors can be used as adjuncts to renal injury grading to guide clinical decision making. LEVEL OF EVIDENCE: Prognostic and Epidemiological Study, Level III and Therapeutic/Care Management, Level IV.

Resuscitative endovascular balloon occlusion of the aorta induced myocardial injury is mitigated by endovascular variable aortic control.

BACKGROUND: The cardiac effects of resuscitative endovascular balloon occlusion of the aorta (REBOA) are largely unknown. We hypothesized that increased afterload from REBOA would lead to cardiac injury, and that partial flow using endovascular variable aortic control (EVAC) would mitigate this injury. METHODS: Eighteen anesthetized swine underwent controlled 25% blood volume hemorrhage. Animals were randomized to either Zone 1 REBOA, Zone 1 EVAC, or no intervention (control) for 45 minutes. Animals were then resuscitated with shed blood, observed during critical care, and euthanized after a 6-hour total experimental time. Left ventricular function was measured with a pressure-volume catheter, and blood samples were drawn at routine intervals. RESULTS: The average cardiac output during the intervention period was higher in the REBOA group (9.3 [8.6-15.4] L/min) compared with the EVAC group (7.2 [5.8-8.0] L/min, p = 0.01) and the control group (6.8 [5.8-7.7] L/min, p < 0.01). At the end of the intervention, the preload recruitable stroke work was significantly higher in both the REBOA and EVAC groups compared with the control group (111.2 [102.5-148.6] and 116.7 [116.6-141.4] vs. 67.1 [62.7-87.9], p = 0.02 and p < 0.01, respectively). The higher preload recruitable stroke work was maintained throughout the experiment in the EVAC group, but not in the REBOA group. Serum troponin concentrations after 6 hours were higher in the REBOA group compared with both the EVAC and control groups (6.26 ± 5.35 ng/mL vs 0.92 ± 0.61 ng/mL and 0.65 ± 0.38 ng/mL, p = 0.05 and p = 0.03, respectively). Cardiac intramural hemorrhage was higher in the REBOA group compared with the control group (1.67 ± 0.46 vs. 0.17 ± 0.18, p = 0.03), but not between the EVAC and control groups. CONCLUSION: In a swine model of hemorrhagic shock, complete aortic occlusion resulted in cardiac injury, although there was no direct decrease in cardiac function. EVAC mitigated the cardiac injury and improved cardiac performance during resuscitation and critical care.