Evaluation of vascular repair by tissue-engineered human acellular vessels or expanded polytetrafluoroethylene grafts in a porcine model of limb ischemia and reperfusion.

BACKGROUND: This study evaluated performance of a tissue-engineered human acellular vessel (HAV) in a porcine model of acute vascular injury and ischemia. The HAV is an engineered blood vessel consisted of human vascular extracellular matrix proteins. Limb reperfusion and vascular outcomes of the HAV were compared with those from synthetic expanded polytetrafluoroethylene (ePTFE) grafts. METHODS: Thirty-six pigs were randomly assigned to four treatment groups, receiving either the HAV or a PTFE graft following a hind limb ischemia period of either 0 or 6 hours. All grafts were 3-cm-long interposition 6-mm diameter grafts implanted within the right iliac artery. Animals were not immunosuppressed and followed for up to 28 days after surgery. Assessments performed preoperatively and postoperatively included evaluation of graft patency, hind limb function, and biochemical markers of tissue ischemia or reperfusion injury. Histological analysis was performed on explants to assess host cell responses. RESULTS: Postoperative gait assessment and biochemical analysis confirmed that ischemia and reperfusion injury were caused by 6-hour ischemia, regardless of vascular graft type. Hind limb function and tissue damage biomarkers improved in all groups postoperatively. Final patency rates at postoperative day 28 were higher for HAV than for ePTFE graft in both the 0-hour (HAV, 85.7%; ePTFE, 66.7%) and 6-hour (HAV, 100%; ePTFE, 75%) ischemia groups, but these differences were not statistically significant. Histological analyses identified some intimal hyperplasia and host reactivity to the xenogeneic HAV and also to the synthetic ePTFE graft. Positive host integration and vascular cell infiltration were identified in HAV but not ePTFE explants. CONCLUSION: Based on the functional performance and the histologic profile of explanted HAVs, this study supports further investigation to evaluate long-term performance of the HAV when used to repair traumatic vascular injuries.

A retrospective cohort comparison of expanded polytetrafluorethylene to autologous vein for vascular reconstruction in modern combat casualty care.

BACKGROUND: Reconstruction of vascular injury often requires use of a conduit, either autologous vein (AV) or expanded polytetrafluorethylene (ePTFE). The most common anatomic locations for and durability of ePTFE as an adjunct to vascular repair in the combat setting are unknown. The objectives of this study were to characterize the anatomic locations of use of ePTFE during the wars in Afghanistan and Iraq and to compare its effectiveness to AV. METHODS: US service personnel undergoing vascular repair (2002-2012) were identified. Patients in whom ePTFE was used as an interposition conduit (n = 25) were matched with similar patients who received AV (n = 24) reconstruction. Injury and operative factors were assessed, and freedom from graft-related complication was quantified using Kaplan-Meier log-rank test. RESULTS: There was no difference between ePTFE and AV with regard to age, injury severity, or mangled extremity severity score. Follow-up for the ePTFE and AV groups was 71 and 62 months, respectively. In the cohort there was an apparent but not significantly greater freedom from graft-related complication for AV compared with ePTFE (65% vs. 17%; P = 0.13). In the carotid, subclavian, and axillary artery positions, ePTFE performed equal to AV with no apparent difference in freedom from graft-related complications (P = 0.90). However, in the periphery, AV demonstrated greater 8-year freedom from graft-related complication than ePTFE (77% vs. 31%, P = 0.044). CONCLUSIONS: AV is a more durable conduit than ePTFE in repair of wartime extremity vascular injury, whereas ePTFE is effective and durable in the carotid, subclavian, and axillary locations.

Functional outcome after resuscitative endovascular balloon occlusion of the aorta of the proximal and distal thoracic aorta in a swine model of controlled hemorrhage.

BACKGROUND: Noncompressible torso hemorrhage remains an ongoing problem for both military and civilian trauma. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been characterized as a potentially life-saving maneuver. The objective of this study was to determine the functional outcomes, paraplegia rates, and survival of 60-min balloon occlusion in the proximal and distal thoracic aorta in a porcine model of controlled hemorrhage. METHODS: Swine (Sus scrofa, 70-110 kg) were subjected to class IV hemorrhagic shock and underwent 60 min of REBOA. Devices were introduced from the left carotid artery and positioned in the thoracic aorta in either the proximal location (pREBOA [n = 8]; just past takeoff of left subclavian artery) or distal location (dREBOA [n = 8]; just above diaphragm). After REBOA, animals were resuscitated with whole blood, crystalloid, and vasopressors before a 4-day postoperative period. End points included evidence of spinal cord ischemia (clinical examination, Tarlov gait score, bowel and bladder dysfunction, and histopathology), gross ischemia-reperfusion injury (clinical examination and histopathology), and mortality. RESULTS: The overall mortality was similar between pREBOA and dREBOA groups at 37.5% (n = 3). Spinal cord-related mortality was 12.5% for both pREBOA and dREBOA groups. Spinal cord symptoms without death were present in 12.5% of pREBOA and dREBOA groups. Average gait scores improved throughout the postoperative period. CONCLUSIONS: REBOA placement in the proximal or distal thoracic aorta does not alter mortality or paraplegia rates as compared with controlled hemorrhage alone. Functional recovery improves in the presence or the absence of REBOA, although at a slower rate after REBOA as compared with negative controls. Additional research is required to determine the ideal placement of REBOA in an uncontrolled hemorrhage model to achieve use compatible with survival outcomes and quality of life.

Use of resuscitative endovascular balloon occlusion of the aorta in a highly lethal model of noncompressible torso hemorrhage.

Noncompressible torso hemorrhage is a leading cause of death in trauma, with many patients dying before definitive hemorrhage control. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an adjunct than can be used to expand the window of salvage in patients with end-stage hemorrhagic shock. The aim of this study was to evaluate the effect of continuous and intermittent REBOA (iREBOA) on mortality using a highly lethal porcine model of noncompressible torso hemorrhage. Male splenectomized pigs (70-90 kg) underwent a laparoscopic liver injury (80% resection of left lobe) followed by a 10-min free-bleed period. Animals were then divided into three groups (n = 8) for a 60-min intervention phase (n = 8): continuous occlusion (cREBOA), iREBOA, or no occlusion (nREBOA). Groups then underwent whole blood resuscitation, damage control surgery, and further critical care. Endpoints were mortality and hemodynamic and circulating measures of shock and resuscitation. Systolic blood pressure (in mmHg) at the end of the free-bleed period for cREBOA, iREBOA, and nREBOA was 31 ± 14, 48 ± 28, and 28 ± 17, respectively (P = 0.125). Following the start of the intervention phase, systolic blood pressure was higher in the iREBOA and cREBOA groups compared with the nREBOA (85 ± 37 and 96 ± 20 vs. 42 ± 4; P < 0.001). Overall mortality for the cREBOA, iREBOA, and nREBOA groups was 25.0%, 37.5%, and 100.0% (P = 0.001). Resuscitative endovascular balloon occlusion of the aorta can temporize exsanguinating hemorrhage and restore life-sustaining perfusion, bridging critical physiology to definitive hemorrhage control. Prospective observational studies of REBOA as a hemorrhage control adjunct should be undertaken in appropriate groups of human trauma patients.

A novel fluoroscopy-free, resuscitative endovascular aortic balloon occlusion system in a model of hemorrhagic shock.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a potentially lifesaving maneuver in the setting of hemorrhagic shock. However, emergent use of REBOA is limited by existing technology, which requires large sheath arterial access and fluoroscopy-guided balloon positioning. The objectives of this study were to describe a new, fluoroscopy-free REBOA system and to compare its efficacy to existing technology. An additional objective was to characterize the survivability of 60 minutes of REBOA using these systems in a model of hemorrhagic shock. METHODS: Swine (70-88 kg) in shock underwent 60 minutes of REBOA using either a self-centering, one component prototype balloon system (PBS, n = 8) inserted (8 Fr) and inflated without fluoroscopy or a two-component, commercially available balloon system (CBS, n = 8) inserted (14 Fr) with fluoroscopic guidance. Following REBOA, resuscitation occurred for 48 hours with blood, crystalloid, and vasopressors. End points included accurate balloon positioning, hemodynamics, markers of ischemia, resuscitation requirements, and mortality. RESULTS: Posthemorrhage mean arterial pressure (mm Hg) was similar in the CBS and PBS groups (35 [8] vs. 34 [5]; p = 0.89). Accurate balloon positioning and inflation occurred in 100% of the CBS and 88% of the PBS group. Following REBOA, mean arterial pressure increased comparably in the CBS and PBS groups (81 [20] vs. 89 [16]; p = 0.21). Lactate peaked in the CBS and PBS groups (10.8 [1.4] mmol/L vs. 13.2 [2.1] mmol/L; p = 0.01) 45 minutes following balloon deflation but returned to baseline by 24 hours. Mortality was similar between the CBS and PBS groups (12% vs. 25%, p = 0.50). CONCLUSION: This study reports the feasibility and efficacy of a novel, fluoroscopy-free REBOA system in a model of shock. Despite a significant physiologic insult, 60 minutes of REBOA is tolerated and recoverable. Development of lower profile, fluoroscopy-free endovascular balloon occlusion catheters may allow proactive aortic control in patients at risk for hemorrhagic shock and cardiovascular collapse.

A nine-day accelerated radiation protocol for feline squamous cell carcinoma.

Nine cats with oral squamous cell carcinoma were treated with an accelerated radiation protocol (14 fractions of 3.5 Gy in 9 days). Radiation was administered twice daily with a 6hour break between treatments. Median overall survival was 86 +/- 110 days. Median survival for cats with a partial response (n=6) was 60 +/- 7 days, while median survival for cats with a complete response (n=3) was 298 +/- 187 days (P = 0.0639). The accelerated protocol was well tolerated and toxicity in the early and late period was manageable in all cats. Further modification of the protocol is warranted to extend survival.

Class, gender and madness in eighteenth-century Scotland.

This chapter uses a wide range of qualitative and quantitative sources from eighteenth-century Scotland to ask whether identifying someone as mad was an arbitrary means of exerting power over them. Separate sections analyse the effect of gender and class on the constructions of mental disability. The conclusion is that rather than providing evidence of a crude bourgeois and/or male conspiracy, understandings of mental incapacity reveal in a subtle and nuanced way the nature and extent of distinctions between people based on their social status, age, occupation and sex.

The Angry Dying Patient.

Over 25 years ago, Kubler-Ross identified anger as a predictable part of the dying process. When the dying patient becomes angry in the clinical setting, all types of communication become strained. Physicians can help the angry dying patient through this difficult time by using 10 rules of engagement. When physicians engage and empathize with these patients, they improve the patient's response to pain and they reduce patient suffering. When physicians educate patients on their normal responses to dying and enlist them in the process of family reconciliation, they can impact the end-of-life experience in a positive way.