Effect of the Abdominal Aortic and Junctional Tourniquet on chest compressions in a swine model of ventricular fibrillation.

INTRODUCTION: Mortality for out-of-hospital cardiac arrest is high when traditional chest compressions are used without adjuncts. The abdominal aortic and junctional tourniquet (AAJT) is a device with a wedge-shaped air bladder that occludes the aortic bifurcation, augmenting blood flow to the heart and brain. Previously, the addition of AAJT during chest compression led to an increase in rate of survival in a model of traumatic cardiac arrest. HYPOTHESIS: This study was designed to determine if application of the AAJT would lead to more effective chest compressions as measured by improved hemodynamic parameters and an increased rate of return of spontaneous circulation (ROSC). METHODS: Yorkshire swine (n = 6 per group) underwent general anesthesia and instrumentation. Ventricular fibrillation (Vfib) was electrically induced and animals were allocated into groups with or without the AAJT. The AAJT was inflated if selected after four minutes of compressions. Following a total of ten minutes of compressions, the animals entered into a ten-minute advanced cardiac life support phase. Hemodynamics and blood gas measurements were compared between groups. RESULTS: ROSC or cardioversion from Vfib was not achieved in either group. The AAJT group had improved hemodynamic parameters with significantly higher carotid diastolic pressure and higher blood flow in the carotid artery (p = 0.016 and 0.028 respectively). However, no significant differences were observed with coronary perfusion pressure or end tidal CO2. CONCLUSION: The AAJT did not confer a survival advantage during chest compressions, but hemodynamic improvements were observed while the AAJT was in place.

Learning Alternative Access Approaches for Transcatheter Aortic Valve Replacement: Implications for New Transcatheter Aortic Valve Replacement Centers.

BACKGROUND: Smaller transcatheter aortic valve replacement (TAVR) delivery systems have increased the number of patients eligible for transfemoral procedures while decreasing the need for transaortic (TAo) or transapical (TA) access. As a result, newer TAVR centers are likely to have less exposure to these alternative access techniques, making it harder to achieve proficiency. The purpose of this study was to evaluate the learning curve for TAVR approaches and compare perioperative outcomes. METHODS: From January 2008 to December 2014, 400 patients underwent TAVR (transfemoral, n = 179; TA, n = 120; and TAo, n = 101)). Learning curves were constructed using metrics of contrast utilization, procedural, and fluoroscopy times. Outcomes during the learning curve were compared with after proficiency was achieved. RESULTS: Depending on the metric, learning curves for all three routes differed slightly but all demonstrated proficiency by the 50th case. There were no significant differences in procedural times whereas improvements in contrast use were most notable for TA (69 ± 40 mL versus 50 ± 23 mL, p = 0.002). For both TA and TAo, fewer patients received transfusions once proficiency was reached (62% versus 34%, p = 0.003, and 42% versus 14%, p = 0.002, respectively). No differences in 30-day or 1-year mortality were seen before or after proficiency was reached for any approach. CONCLUSIONS: The learning curves for TA and TAo are distinct but technical proficiency begins to develop by 25 cases and becomes complete by 50 cases for both approaches. Given the relatively low volume of alternative access, achieving technical proficiency may take significant time. However, technical proficiency had no effect on 30-day or 1-year mortality for any access approach.

Interatrial Bronchogenic Cyst Resection.

Interatrial bronchogenic cysts are rare entities, and the long-term clinical sequelae are unknown. This case report details the removal of a large (>4 cm) interatrial bronchogenic cyst that had been present for more than 10 years. Surgical resection remains the current standard of therapy when encountering an interatrial mass.

Prophylactic fasciotomy in a porcine model of extremity trauma.

BACKGROUND: Extremity injury, with concomitant hemorrhagic shock, can result in ischemia-reperfusion injury and the formation of compartment syndrome requiring fasciotomy. As the benefit of prophylactic fasciotomy is unclear, the objective of this study is to determine the functional recovery of an ischemic limb with hemorrhagic shock after prophylactic fasciotomy. MATERIAL AND METHODS: Yorkshire swine underwent 35% blood volume hemorrhage, followed by 1, 3, and 6 h of ischemia (n = 17; 1HR, 3HR, and 6HR) via iliac artery occlusion followed by repair and reperfusion. A second cohort (n = 18) underwent fasciotomy of the anterior compartment of the hind limb following vascular repair (1HR-F, 3HR-F, and 6HR-F). Compartment pressures, measures of electromyographic (EMG) recovery, and a validated gait score (modified Tarlov) were performed throughout a 14-d survival period. RESULTS: Increasing ischemic intervals resulted in incremental increases in compartment pressure (P < 0.05), although the mean did not exceed 30 mm Hg. EMG studies did not show a significant improvement comparing the 3HR with 6HR groups. There was a significant improvement in the EMG studies within the 3HR-F, when compared with 6HR-F. There was a trend toward sensory improvement between the 3HR-F and 3HR groups. However, this did not translate to a difference in functional outcome as measured by the Tarlov gait score. CONCLUSIONS: Within this swine model of hemorrhagic shock and hind limb ischemia, the use of prophylactic fasciotomies did not improve functional outcome.

Physiologic tolerance of descending thoracic aortic balloon occlusion in a swine model of hemorrhagic shock.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging technique in trauma; however, the physiologic sequelae have not been well quantified. The objectives of this study were to characterize the burden of reperfusion and organ dysfunction of REBOA incurred during 30 or 90 min of class IV shock in a survivable porcine model of hemorrhage. METHODS: After induction of shock, animals were randomized into 4 groups (n = 6): 30 min of shock alone (30-Shock) or with REBOA (30-REBOA) and 90 min of shock alone (90-Shock) or with REBOA (90-REBOA). Cardiovascular homeostasis was then restored with blood, fluid, and vasopressors for 48 h. Outcomes included mean central aortic pressure (MCAP), lactate concentration, organ dysfunction, histologic evaluation, and resuscitation requirements. RESULTS: Both REBOA groups had greater MCAPs throughout their shock phase compared to controls (P < .05) but accumulated a significantly greater serum lactate burden, which returned to control levels by 150 min in the 30-REBOA groups and 320 min in the 90-REBOA group. There was a greater level of renal dysfunction and evidence of liver necrosis seen in the 90-REBOA group compared to the 90-Shock group. There was no evidence of cerebral or spinal cord necrosis in any group. The 90-REBOA group required more fluid resuscitation than the 90-Shock group (P = .05). CONCLUSION: REBOA in shock improves MCAP and is associated with a greater lactate burden; however, this lactate burden returned to control levels within the study period. Ultimately, prolonged REBOA is a survivable and potentially life-saving intervention in the setting of hemorrhagic shock and cardiovascular collapse in the pig.

Aortic balloon occlusion is effective in controlling pelvic hemorrhage.

BACKGROUND: The objective of this study was to evaluate the efficacy of resuscitative endovascular aortic balloon occlusion (REBOA) of the distal aorta in a porcine model of pelvic hemorrhage. METHODS: Swine were entered into three phases of study: injury (iliac artery), hemorrhage (45 s), and intervention (180 min). Three groups were studied: no intervention (NI, n = 7), a kaolin-impregnated gauze (Combat Gauze) (CG, n = 7), or REBOA (n = 7). The protocol was repeated with a dilutional coagulopathy (CG-C, n = 7, and REBOA-C, n = 7). Measures of physiology, rates of hemorrhage, and mortality were recorded. RESULTS: Rate of hemorrhage was greatest in the NI group, followed by the REBOA and CG groups (822 ± 415 mL/min versus 11 ± 13 and 0.2 ± 0.4 mL/min respectively; P < 0.001). MAP following intervention (at 15 min) was the same in the CG and REBOA groups and higher than in the NI group (70 ± 4 and 70 ± 11 mm Hg versus 5 ± 13 mm Hg respectively; P < 0.001). There was 100% mortality in the NI group, with no deaths in the CG or REBOA group. In the setting of coagulopathy, the rate of bleeding was higher in the CG-C versus the REBOA-C group (229 ± 295 mL/min versus 20 ± 7 mL/min, P = 0.085). MAP following intervention (15 min) was higher in the REBOA-C than the CG-C group (71 ± 12 mm Hg versus 28 ± 31 mm Hg; P = 0.005). There were 5 deaths (71.4%) in the CG-C group, but none in the REBOA-C group (P = 0.010). CONCLUSION: Balloon occlusion of the aorta is an effective method to control pelvic arterial hemorrhage. This technique should be further developed as an adjunct to manage noncompressible pelvic hemorrhage.

Compartment syndrome in the setting of vascular injury.

Compartment syndrome after extremity vascular injury has gained attention with the current conflicts in Iraq and Afghanistan. Compartment syndrome after extremity vascular injury is due to the initial ischemic insult and reperfusion injury. Complications from compartment syndrome can be lessened by fasciotomy, which is reviewed in this article.