Preperitoneal balloon tamponade and resuscitative endovascular balloon occlusion of the aorta: Alternatives to open packing for pelvic fracture-associated hemorrhage.

BACKGROUND: The objective of this study was to compare the efficacy of preperitoneal balloon tamponade (PPB), resuscitative endovascular balloon occlusion of the orta (REBOA), and open preperitoneal packing (OP) in a realistic animal model of pelvic fracture-associated hemorrhage. METHODS: Thirty-nine swine underwent creation of open-book pelvic fracture and iliac vascular injury. Animals were randomized to no intervention (n = 7), OP (n = 10), PPB (n = 9), zone 1 REBOA (n = 7), and zone 3 REBOA (n = 6) at a mean arterial pressure less than 40 mm Hg from uncontrolled hemorrhage. Primary outcome was survival at 1 hour. Secondary outcomes included survival in the immediate 10 m following intervention reversal, peak preperitoneal pressure (PP), blood loss, bleed rate, and peak lactate. RESULTS: Prior to injury, no difference was measured between groups for weight, hemodynamics, lactate, and hematocrit (all p = NS). The injury was uniformly lethal without intervention, with survival time (mean) of 5 m, peak PP of 14 mm Hg, blood loss of 960 g, bleed rate of 450 g/m, and peak lactate of 2.6 mmol/L. Survival time (m) was extended to 44 with OP, 60 with PPB, and 60 with REBOA (p < 0.01). Peak PP (mm Hg) was 19 with OP, 23 with PPB, 10 with zone 1 REBOA, and 6 with zone 3 REBOA (p < 0.05). Blood loss (g) was 850 with OP, 930 with PPB, 610 with zone 1 REBOA, and 370 with zone 3 REBOA (p < 0.01). Peak lactate (mmol/L) was 3.3 with OP, 4.3 with PPB, 13.4 with zone 1 REBOA, and 5.3 with zone 3 REBOA (p < 0.01). Only 33% of zone 1 REBOA animals survived the initial 10 m after balloon deflation, compared to 60% for OP, 67% for PPB, and 100% for zone 3 REBOA (p < 0.01). CONCLUSION: Preperitoneal balloon tamponade and zone 3 REBOA are effective alternatives to OP in this animal model of lethal pelvic fracture-associated hemorrhage. Zone 1 REBOA extends survival time but with high mortality upon reversal.

Minimally invasive preperitoneal balloon tamponade and abdominal aortic junctional tourniquet versus open packing for pelvic fracture-associated hemorrhage: Not all extrinsic compression is equal.

BACKGROUND: Minimally invasive preperitoneal balloon tamponade (PPB) and abdominal aortic junctional tourniquets (AAJT) have been proposed as alternatives to open preperitoneal packing (OP) for the management of pelvic fracture-associated hemorrhage. We hypothesized that the PPB (SpaceMaker Pro) and AAJT would result in similar rates of survival and blood loss versus OP. METHODS: Thirty-two swine underwent creation of a combined open-book pelvic fracture and major iliac vascular injuries. Animals were randomized to no intervention (n = 7), OP (n = 10), PPB (n = 9), or AAJT (n = 6) at a mean arterial pressure <40 mm Hg following initiation of uncontrolled hemorrhage. Survival (up to 60 minutes + 10 minutes after intervention reversal), hemodynamics, extraperitoneal pressures, blood loss, and associated complications were compared between groups. RESULTS: Prior to injury, no difference was measured between groups for weight, hemodynamics, lactate, and hematocrit (all p > 0.05). The injury was uniformly lethal without intervention, with survival time (mean) of 5 minutes, peak preperitoneal pressure (PP) of 14 mm Hg, blood loss of 960 g, and peak lactate of 2.6 mmol/L. Survival time was 44 minutes with OP versus 60 minutes with PPB and AAJT (p < 0.01). Peak PP (mm Hg) was 19 with OP, 23 with PPB, and 23 with AAJT (p > 0.05). Blood loss (g) was 850 with OP, 930 with PPB, and 600 with AAJT (p > 0.05). Peak lactate (mmol/L) was 3.3 with OP, 4.3 with PPB, and 6.3 with AAJT (p < 0.01). Only 33% of AAJT animals survived intervention reversal versus 60% for OP and 67% for PPB (p < 0.01). Necropsy revealed bowel/bladder injury in 50% of AAJT subjects versus 0% in all other arms (p < 0.01). CONCLUSION: Preperitoneal balloon tamponade is a safe and potentially effective alternative to OP for the management of lethal pelvic fracture-associated hemorrhage. Abdominal aortic junctional tourniquet offers a similar survival benefit to PPB but has concerning rates of ischemia-reperfusion and compressive abdominal organ injury.

There's an app for that: A handheld smartphone-based infrared imaging device to assess adequacy and level of aortic occlusion during REBOA.

BACKGROUND: Advances in thermal imaging devices have made them an appealing noninvasive point-of-care imaging adjunct in the trauma setting. We sought to assess whether a smartphone-based infrared imaging device (SBIR) could determine presence and location of aortic occlusion in a swine model. We hypothesized that various levels of aortic occlusion would transmit significantly different heat signatures at various anatomical points. METHODS: Six swine (35-50 kg) underwent sequential zone 1 (Z1) aortic cross clamping as well as zone 3 (Z3) aortic balloon occlusion (resuscitative endovascular balloon occlusion of the aorta [REBOA]). SBIR images and readings (FLIR One) were taken at five anatomic points (axilla [A], subcostal [S], umbilical [U], inguinal [I], medial malleolar [M]) and were used to determine significant thermal trends 5 minutes to 10 minutes after Z1 and Z3 occlusion. Significant (p ≤ 0.05) thermal ratio patterns were identified and compared among groups, and images were reviewed for obvious qualitative differences at the various levels of occlusion. RESULTS: Body temperatures were similar during control (CON), Z1 occlusion, and Z3 occlusion, ranging from 94.0 °F to 100.9 °F (p = 0.126). No significant temperature differences were found among A, S, U, I, M points prior to and after aortic occlusions. Among the anatomical 2-point ratios evaluated, A/M and S/M ratios were the best predictors of aortic occlusion, whether at Z1 (8.2 °F, p < 0.01; 10.9 °F, p < 0.01) or Z3 (7.3 °F, p < 0.01; 8.4 °F, p < 0.01), respectively. The best predictor of Z1 versus Z3 level of occlusion was the S/I ratio (5.2 °F, p < 0.05 vs. 3.4 °F, p = 0.27). SBIR generated qualitatively different thermal signatures among groups. CONCLUSION: SBIR was capable of detecting thermal trends during Z1 and Z3 aortic occlusion by using an anatomical 2-point thermal ratio. There were also easily recognized qualitative differences between control and occlusion images that would allow immediate determination of adequate occlusion of the aorta. SBIR represents a potential inexpensive and accurate tool for assessing perfusion, adequate REBOA placement, and even the aortic level of occlusion.

Preperitoneal balloon tamponade for lethal closed retroperitoneal pelvic hemorrhage in a swine model: A comparable and minimally invasive alternative to open pre-peritoneal pelvic packing.

BACKGROUND: The management of massive pelvic fracture-associated hemorrhage is extremely challenging, particularly in the unstable patient. We sought to characterize and compare the efficacy of a minimally invasive preperitoneal balloon technique (MIB) to standard open packing. METHODS: Twenty-six swine were randomized to control (C), open preperitoneal packing technique (OP), and MIB groups. A closed extraperitoneal iliac vascular injury followed by intervention + resuscitation over a 120-minute OP and MIB efficacy was assessed by procedure time, hemodynamics, extraperitoneal tamponade pressures (ETPs), blood loss, and survival. Angiography was performed in select animals, and ETPs were also measured in humans undergoing MIB placement for an elective procedure. RESULTS: Baseline parameters (mean arterial pressure [MAP] 29, 38, and 38 mm Hg; cardiac index [CI] 3.5, 3.8, and 4.2; and EPTs 5, 4, and 5 mm Hg) were similar among C, OP, and MIB groups, respectively (all p's > 0.05). The OP and MIB groups had markedly improved MAP and CI versus C. MIB generated significantly higher ETP (28 vs 17 mm Hg), was faster to deploy (164 vs 497 seconds), and had lower total blood loss versus OP (0.7 vs 1.2 L, all p's < 0.05). OP and MIB had equivalent survival times that were significantly improved versus C (91 and 116 vs 43 minutes, p < 0.05). Survival to 2 hours was 80% with OP versus 100% in the MIB group. Angiography showed no active extravasation in both study groups, but controlled partial deflation of the MIB allowed easy visualization of extravasation. Minimally invasive preperitoneal balloon inflation in five human subjects demonstrated a significant increase in mean ETP from 2.4 to 31 mm Hg (p < 0.01). CONCLUSION: Minimally invasive preperitoneal balloon tamponade was as effective as OP in improving hemodynamics and prolonging survival times, and performed superiorly to OP in time to placement, blood loss, and generation of tamponade pressures. The MIB allows for controlled deflation and reinflation to facilitate angiographic interventions, and may represent a promising new bedside intervention in this patient population.

Inducing metabolic suppression in severe hemorrhagic shock: Pilot study results from the Biochronicity Project.

BACKGROUND: Suspended animation-like states have been achieved in small animal models, but not in larger species. Inducing metabolic suppression and temporary oxygen independence could enhance survivability of massive injury. Based on prior analyses of key pathways, we hypothesized that phosphoinositol-3-kinase inhibition would produce metabolic suppression without worsening organ injury or systemic physiology. METHODS: Twenty swine were studied using LY294002 (LY), a nonselective phosphoinositol-3-kinase inhibitor. Animals were assigned to trauma only (TO, n = 3); dimethyl sulfoxide only (DMSO, n = 4), LY drug only (LYO, n = 3), and drug + trauma (LY + T, n = 10) groups. Both trauma groups underwent laparotomy, 35% hemorrhage, severe ischemia/reperfusion injury, and protocolized resuscitation. Laboratory, physiologic, cytokine, and metabolic cart data were obtained. Histology of key end organs was also compared. RESULTS: Baseline values were similar among the groups. Compared with the TO group, the LYO group had reversible decreases in heart rate, mean arterial pressure, cardiac output, oxygen consumption, and carbon dioxide production. Compared with TO, LY + T showed sustained decreases in heart rate (113 vs. 76, p = 0.03), mean arterial pressure (40 vs. 31 mm Hg, p = 0.02), and cardiac output (3.8 vs. 1.9 L/min, p = 0.05) at 6 hours. Metabolic parameters showed profound suppression in the LY + T group. Oxygen consumption in LY + T was lower than both TO (119 vs. 229 mL/min, p = 0.012) and LYO (119 vs. 225 mL/min, p = 0.014) at 6 hours. Similarly, carbon dioxide production was decreased at 6 hours in LY + T when compared with TO (114 vs. 191 mL/min, p = 0.043) and LYO (114 vs. 195 mL/min, p = 0.034) groups. There was no worsening of acidosis (lactate 6.4 vs. 8.3 mmol/L, p = 0.4) or other endpoints. Interleukin 6 (IL-6) showed a significant increase in LY + T when compared with TO at 6 hours (60.5 vs. 2.47, p = 0.043). Tumor necrosis factor α and IL-1ß were decreased, and IL-10 increased in TO and LY + T at 6 hours. Markers of liver and kidney injury were no different between TO and LY + T groups at 6 hours. CONCLUSIONS: Phosphoinositol-3-kinase inhibition produced metabolic suppression in healthy and injured swine without increasing end-organ injury or systemic physiologic markers and demonstrated prolonged efficacy in injured animals. Further study may lead to targeted therapies to prolong tolerance to hemorrhage and extend the "golden hour" for injured patients.

Efficacy of a novel fluoroscopy-free endovascular balloon device with pressure release capabilities in the setting of uncontrolled junctional hemorrhage.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as an alternative to gauze packing (GP) in the setting of noncompressible torso hemorrhage. Our objective was to describe placement and physiologic impact of a novel REBOA device during uncontrolled junctional hemorrhage. We hypothesized that REBOA could be deployed without fluoroscopic guidance or intra-aortic barotrauma and could increase survival in the setting of profound shock physiology. METHODS: Fourteen adult swine (35-50 kg) underwent a hemorrhage and ischemia/reperfusion injury protocol to produce shock physiology and dilutional coagulopathy and randomized to REBOA (n = 8) or standard GP (n = 6) groups. A complex contralateral groin soft tissue and vascular injury was then created, followed by 30 seconds of free bleeding and GP for 5 minutes. The REBOA group had the aortic balloon inflated in aortic Zone III until the pressure release valve opened, followed by 45-minute postpacking survival, after which native and balloon-exposed aortae were harvested for histologic analysis. RESULTS: Control and REBOA groups had similar baseline hemodynamics (mean arterial pressure, 32 mm Hg vs. 43 mm Hg; p = 0.228), levels of coagulopathy (international normalized ratio, 1.3 vs. 1.2, p = 0.476; fibrinogen, 108 vs. 135 mg/dL, p = 0.747), and hemorrhage/ischemia/reperfusion insult (lactate, 7 vs. 7, p = 0.950; base deficit, 9 vs. 5, p = 0.491). No histologic barotrauma was identified, and 88% of the REBOA devices were successfully deployed into the Zone III of the aorta. The REBOA group had significantly decreased hemorrhage volumes (0.5 L vs. 0.2 L, p = 0.014) and increased survival times (45 minutes vs. 8 minutes, p < 0.001). CONCLUSION: This study reinforces results found in previous studies that REBOA is an effective method to increase survival in the setting of noncompressible torso hemorrhage and is the first to show that this specific REBOA device can be blindly guided into the appropriate zone of the aorta without generating aortic wall injury during unmeasured balloon inflation.

Prehospital interventions in severely injured pediatric patients: Rethinking the ABCs.

BACKGROUND: The current conflict in Afghanistan has resulted in a high volume of significantly injured pediatric patients. The austere environment has demanded emphasis on prehospital interventions (PHIs) to sustain casualties during transport. METHODS: The Department of Defense Trauma Registry was queried for all pediatric patients (≤18 years) treated at Camp Bastion from 2004 to 2012. PHIs were grouped by Advanced Trauma Life Support categories into (1) airway (A)--intubation or surgical airway; 2) breathing (B)--chest tube or needle thoracostomy; and 3) circulation (C)--tourniquet or hemostatic dressing. Outcomes were assessed based on injury severity, hemodynamics, blood products and fluids, as well as mortality rates. RESULTS: There were 766 injured children identified with 20% requiring one or more PHIs, most commonly circulation (C, 51%) followed by airway (A, 40%) and breathing (B, 8.7%). The majority of C interventions were tourniquets (85%) and hemostatic dressings (15%). Only 38% of patients with extremity vascular injury or amputation received a C intervention, with a significant reduction in blood products and intravenous fluids associated with receiving a C PHI (both p < 0.05). A interventions consisted of endotracheal intubation for depressed mental status (Glasgow Coma Scale [GCS] score < 8). Among patients with traumatic brain injury, A interventions were associated with higher unadjusted mortality (56% vs. 20%, p < 0.01) and remained independently associated with increased mortality after multivariate adjustment (odds ratio, 5.9; p = 0.001). B interventions were uncommon and performed in only 2% of patients with no recorded adverse outcomes. CONCLUSION: There is a high incidence of PHIs among pediatric patients with severe wartime injuries. The most common and effective were C PHI for hemorrhage control, which should remain a primary focus of equipment and training. A interventions were most commonly performed in the setting of severe traumatic brain injury but were associated with worse outcomes. B interventions seem safe and effective and may be underused. LEVEL OF EVIDENCE: Care management/therapeutic study, level IV.

Sugar or salt? The relative roles of the glucocorticoid and mineralocorticoid axes in traumatic shock.

BACKGROUND: Glucocorticoid deficiency (GD) has been proposed as a key contributor to shock states, but the presence and role of acute mineralocorticoid deficiency may be of equal or greater significance. We sought to analyze the incidence and degree of acute mineralocorticoid deficiency and GD in an animal model of severe hemorrhage and shock. METHODS: Fifty-seven swine underwent 35% volume-controlled hemorrhage followed by aortic cross-clamping for 50 minutes to induce truncal ischemia-reperfusion. Protocol-guided resuscitation was performed. Laboratory analysis included cortisol, aldosterone, and plasma renin activity. The aldosterone-to-renin ratio (ARR) was calculated at each time point, and changes were correlated to markers of perfusion. RESULTS: Mean baseline cortisol levels were 5.8 µg/dL. Following hemorrhage, there was a significant increase in mean cortisol to 9.2 µg/dL (p < 0.001). After 1 hour of reperfusion, there was no change in mean cortisol levels (9.8 µg/dL, p = 0.12). Mean baseline aldosterone was 13.3 pg/mL. Aldosterone levels before cross-clamp removal increased significantly to 115.1 pg/mL (p < 0.001) and then rapidly declined to 49.2 pg/mL (p < 0.001) after 1 hour of reperfusion. Conversely, baseline plasma renin activity was 0.75 ng/mL per hour and increased significantly before cross-clamp removal (1.8) and at 1 hour (8.9, both p < 0.001). The ARR at baseline was 96.1 and increased to 113.5 (p = 0.68) before cross-clamp removal but significantly declined following 1 hour of reperfusion to 7.6 (p < 0.001). Overall, this represented a 93% reduction in mean ARR following reperfusion. The degree of aldosterone deficiency correlated with degree of systemic shock as measured by arterial base deficit (r = 0.47, p = 0.04), while cortisol showed no correlation. CONCLUSION: Hemorrhagic shock with ischemia-reperfusion injury resulted in only modest impact on the glucocorticoid axis, but major dysfunction of the mineralocorticoid axis and severe hyperreninemic hypoaldosteronism. The degree of aldosterone deficiency may provide prognostic information or offer potential targets for pharmacologic intervention. LEVEL OF EVIDENCE: Diagnostic study, level III.

The utility of pathologic evaluation of adult hernia specimens.

BACKGROUND: Pathological examination of hernia sac specimens adds additional steps and cost to a surgical procedure but has no proven benefit. Although well studied in pediatrics, there are limited data in the adult literature pertaining to this practice. METHODS: This is a retrospective analysis from a single institution referral center over a 4-year period (2007 to 2011). All inguinal, incisional, ventral, and umbilical hernia repairs greater than 18 years of age were included. RESULTS: A total of 1,216 inguinal (55.4%), incisional (11.4%), umbilical (21.5%), or ventral hernia (11.7%) repairs were included. In 246 cases (20.2%), hernia sac specimens were sent to pathology (open 96.7%; laparoscopic 3.3%). There were no cases in which management of the patient changed because of the final results. CONCLUSION: The rarity of changes in diagnosis and treatment from routine pathologic examination of a hernia sac does not justify this practice and indicates that it may be omitted except in unique circumstances.