Shannon T. Marko

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.

RESUSCITATIVE ENDOVASCULAR BALLOON OCCLUSION OF THE AORTA (REBOA) FOR MAJOR ABDOMINAL VENOUS INJURY IN A PORCINE HEMORRHAGIC SHOCK MODEL.

BACKGROUND Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a rescue maneuver for unstable patients with noncompressible hemorrhage below the diaphragm. The efficacy of REBOA in the setting a major abdominal venous injury is unknown. Our objective was to examine the use of REBOA in a large animal model of major abdominal venous injury and characterize any impact on the hemodynamics, rate and volume of hemorrhage, and survival. METHODS Ten swine (35–55 kg) underwent a controlled and validated hemorrhage and ischemia/reperfusion injury protocol to produce shock physiology. Animals were randomly assigned to a control arm (N = 5) or a treatment (REBOA) arm (N = 5). An injury was then created in the common iliac vein. Bleeding was allowed for 60 seconds and the balloon was then inflated in the REBOA arm. Hemodynamics were recorded for 45 minutes or until death. Blood loss was verified post-mortem and bleeding rate calculated. RESULTS All animals demonstrated shock physiology at the time of randomization. There were no differences between control versus REBOA animals in baseline mean arterial pressure (42 vs. 50), pH (7.29 vs. 7.26), lactate (6.19 vs. 6.26), or INR (1.2 vs. 1.3, all p = NS). REBOA animals demonstrated immediate improvements in mean arterial pressure (50.6 vs. 97.2, p = 0.04). The mean survival time was 4.1 minutes for controls (100% died) versus 40.1 minutes for REBOA (p < 0.01). There was no difference in total blood loss (mean 630 mL for both). The rate of bleeding was significantly lower in the REBOA animals (control 197 mL/min vs. REBOA 14 mL/min, p = 0.02). CONCLUSION In the setting of an abdominal venous injury, REBOA improved hemodynamics and lengthened survival time. Blood loss was similar between groups but the rate of bleeding was markedly decreased with REBOA. REBOA appears effective for central venous injuries and provides a sustained period of stabilization and window for surgical intervention.

Smartphone-based mobile thermal imaging technology to assess limb perfusion and tourniquet effectiveness under normal and blackout conditions

BACKGROUND Over the past decade, there has been a resurgence of tourniquet use in civilian and military settings. Several key challenges include assessment of limb perfusion and adequacy of tourniquet placement, particularly in the austere or prehospital environments. We investigated the utility of thermal imaging to assess adequacy of tourniquet placement. METHODS The FLIR ONE smartphone-based thermal imager was utilized. Ten swine underwent tourniquet placement with no associated hemorrhage (n = 5) or with 40% hemorrhage (n = 5). Experiment 1 simulated proper tourniquet application, experiment 2 had one of two tourniquets inadequately tightened, and experiment 3 had one of two tourniquets inadequately tightened while simulating blackout-combat conditions. Static images were taken at multiple time points up to 30 minutes. Thermal images were then presented to blinded evaluators who assessed adequacy of tourniquet placement. RESULTS The mean core temperature was 38.3 °C in non-hemorrhaged animals versus 38.2 °C in hemorrhaged animals. Hemorrhaged animals were more hypotensive (p = 0.001), anemic (p < 0.001), vasodilated (p = 0.008), and had a lower cardiac output (p = 0.007) compared to non-hemorrhaged animals. The thermal imaging temperature reading decreased significantly after proper tourniquet placement in all animals, with no difference between hemorrhaged and non-hemorrhaged groups at 30 minutes (p = 0.23). Qualitative thermal image analysis showed clearly visible perfusion differences in all animals between baseline, adequate tourniquet, and inadequate tourniquet in both hemorrhaged and non-hemorrhaged groups. Ninety-eight percent of blinded evaluators (n = 62) correctly identified adequate and inadequate tourniquet placement at 5 minutes. Images in blackout conditions showed no adverse impact on thermal measurements or in the ability to accurately characterize perfusion and tourniquet adequacy. CONCLUSIONS A simple handheld smartphone-based forward looking infrared radiometry device demonstrated a high degree of accuracy, reliability, and ease of use for assessing limb perfusion. Forward looking infrared radiometry also allowed for rapid and reliable identification of adequate tourniquet placement that was not affected by major hemorrhage or blackout conditions.

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 &agr; and IL-1&bgr; 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.

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.

Three- versus four-factor prothrombin complex concentrates for “factor-based” resuscitation in a porcine hemorrhagic shock model

BACKGROUND Bleeding is a leading cause of preventable death after severe injury. Prothrombin complex concentrates (PCC) treat inborn coagulation disorders and reverse oral anticoagulants, but are proposed for use in “factor-based” resuscitation strategies. Few studies exist for this indication in acidosis, or that compare 3-factor PCC (3PCC) versus 4-factor PCC (4PCC) products. We aimed to assess and compare their safety and efficacy in a porcine model of severe hemorrhagic shock and coagulopathy. METHODS Twenty-five adult Yorkshire swine underwent 35% volume hemorrhage, ischemia-reperfusion injury, and protocolized crystalloid resuscitation. Seventeen animals were randomized at 4 hours after model creation to receive a 45-IU/kg dose of either 3PCC or 4PCC. An additional eight animals received autologous plasma transfusion before 4PCC to better characterize response to PCC. Individual factor levels were drawn at 4 hours and 6 hours. RESULTS The model created significant acidosis with mean pH of 7.21 and lactate of 9.6 mmol/L. After PCC, 66.7% of 3PCC animals and 25% of 4PCC animals (regardless of plasma administration) developed consumptive coagulopathy. The animals that developed consumptive coagulopathy had manifested the “lethal triad” with lower temperatures (36.3°C vs. 37.8°C), increased acidosis (pH, 7.14 vs. 7.27; base excess, −12.1 vs. –6.5 mEq/L), and worse coagulopathy (prothrombin time, 17.1 vs. 14.6 seconds; fibrinogen, 87.9 vs. 124.1 mg/dL) (all p < 0.05). In the absence of a consumptive coagulopathy, 3PCC and 4PCC improved individual clotting factors with transient improvement of prothrombin time, but there was significant depletion of fibrinogen and platelets with no lasting improvement of coagulopathy. CONCLUSION PCC failed to correct coagulopathy and was associated with fibrinogen and platelet depletion. Of greater concern, PCC administration resulted in consumptive coagulopathy in the more severely ill animals. The incidence of consumptive coagulopathy was markedly increased with 3PCC versus 4PCC, and these products should be used with caution in this setting.

Evaluation of a novel thoracic entry device versus needle decompression in a tension pneumothorax swine model

INTRODUCTION Tension pneumothorax (tPTX) remains a major cause of preventable death in trauma. Needle decompression (ND) has up to a 60% failure rate. METHODS Post-mortem swine used. Interventions were randomized to 14G-needle decompression (ND, n = 25), bladed trocar with 36Fr cannula (BTW, n = 16), bladed trocar alone (BTWO, n = 16) and surgical thoracostomy (ST = 11). Simulated tPTX was created to a pressure(p) of 20 mmHg. RESULTS Success (p < 5 mmHg by 120 s) was seen in 41 of 68 (60%) interventions. BTW and BTWO were consistently more successful than ND with success rates of 88% versus 48% in ND (p < .001). In successful deployments, ND was slower to reach p < 5 mmHg, average of 82s versus 26s and 28s for BTW and BTWO respectively (p < .001). Time to implement procedure was faster for ND with an average of 3.6s versus 16.9s and 15.3s in the BTW and BTWO (p < .001). Final pressure was significantly less in BTW and BTWO at 1.7 mmHg versus 7 mmHg in ND animals (p < .001). CONCLUSION Bladed trocars can safely and effectively tPTX with a significantly higher success rates than needle decompression.

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 ps > 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 ps < 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.