Jeffrey Punch

Extracorporeal support for organ donation after cardiac death effectively expands the donor pool.

Background:We sought to evaluate the effect on short-term outcomes of normothermic, extracorporeal perfusion (ECMO) for donation of abdominal organs for transplantation after cardiac death (DCD). Study parameters included increase in number of donors and organs, types of organs procured, and viabili

Vancomycin-Resistant Enterococcal Colonization and Infection in Liver Transplant Candidates and Recipients: A Prospective Surveillance Study

BACKGROUND Vancomycin-resistant enterococcal (VRE) infections cause significant morbidity and mortality among patients undergoing liver transplantation. We performed a prospective study among patients awaiting transplantation to assess rates, risk factors, and outcomes associated with VRE colonization before and after transplantation. METHODS All adults on the transplantation waiting list from 2000-2003 were eligible. Demographic, historical, and laboratory data, as well as stool samples to be analyzed for VRE, were collected at enrollment and every 4-6 months thereafter until transplantation. After transplantation, samples were obtained every 3 days during hospitalization and were analyzed for VRE; outcomes were assessed at 90 days. RESULTS Overall, 375 patients were enrolled in our study, and 142 received transplants. VRE colonization occurred in 50 (13%) of 375 patients before transplantation and was independently associated with treatment with antianaerobic antimicrobials, third-generation cephalosporins, proton pump inhibitors, or neomycin; having a recent endoscopic retrograde cholangiopancreatogram or paracentesis procedure; and admission to the liver unit. Of these 50 patients, 22 (44%) received a transplant, and 7 (32%) of 22 developed a VRE infection after transplantation. An additional 22 patients (18%) who were not colonized before transplantation acquired VRE after transplantation; VRE infection developed in 5 (23%) of these patients. Patients colonized with VRE either before or after transplantation had longer stays in the intensive care unit and the hospital. Mortality at 90 days was significantly greater among those who acquired VRE after transplantation (5 [23%] of 22), compared with those who had VRE colonization before transplantation (2 [9%] of 22). CONCLUSIONS Liver transplantation candidates with VRE colonization before transplantation experience greater morbidity but not greater mortality, compared with noncolonized candidates. Transplant recipients who acquire VRE after transplantation have a higher mortality rate than noncolonized recipients. Strategies should be implemented to reduce nosocomial VRE acquisition after transplantation among this vulnerable group.

Acute lung injury following reperfusion after ischemia in the hind limbs of rats.

In this study, we proposed that oxygen free radicals participate in the acute pulmonary injury that follows limb ischemia/reperfusion. Using an established model of hind limb ischemia, reproducible lung injury occurred after reperfusion. Lung microvascular permeability was measured with 125I-BSA and increased two-fold after 30 minutes of reperfusion. Pulmonary injury was blocked with DMSO, DMTU, allopurinol, indomethacin, and SOD plus catalase. The degree of pulmonary neutrophil sequestration as assessed by tissue myeloperoxidase activity was significantly diminished in animals pretreated with antioxidants. Pretreatment with indomethacin did not attenuate the neutrophil sequestration within the pulmonary parenchyma. These data suggest that increased lung microvascular permeability and neutrophil accumulation occur following hind limb ischemia/reperfusion. Therapeutic interventions with oxygen radical inhibitors blocked this process, while the prostaglandin inhibitor, indomethacin, only reduced lung permeability.

The stress response in skin : the role of neutrophil products in preconditioning

&NA; In this study we tested the hypothesis that neutrophil products are present in ischemic skin flaps and that they are abolished with preconditioning of the skin. Random back flaps were created on rats, and the sequential appearance of neutrophil products and tissue oxidants was measured in the skin flaps. These flaps had predictable skin necrosis (4.7 ± 0.8 cm) in the distal ends, while preconditioned flaps had no skin necrosis. Neutrophil products were assayed by both histomorphometrics and myeloperoxidase assays. Lipid peroxidation products were measured to assess tissue oxident production. These data demonstrate that there is an increase in myeloperoxidase activity in skin flaps that is statistically significantly greater in the distal ends of the flaps at 24 hours (p < 0.05). The lipid peroxidation products were statistically significantly elevated at 48 hours in the distal ends (p < 0.05). Preconditioning the skin as a bipedicled skin flap for 7 days and then dividing the distal attachment abolished neutrophil products and tissue oxidant activity in the skin flaps (p < 0.05). These data suggest that neutrophil products and oxidant priduction are increased in ischemic skin and that preconditioning of the flap markedly attenuates this response.

Identification of xanthine oxidase activity following reperfusion in human tissue.

&NA; In this series of experiments, we surveyed xanthine oxidase activity after microvascular transfer in the venous effluent after reperfusion of human rectus abdominis muscle (n = 8) and jejunum (n = 4). Enzyme activity was correlated with duration of ischemia and biochemical markers of cellular injury. Xanthine oxidase (XO) activity was measured spectrofluorometrically using a pterin assay, whereas cellular injury was measured with commercial creatinine phosphokinase activity assay and lipid peroxidation products using a spectrophotometer. The data demonstrated that XO activity was statistically significantly increased in muscle flaps kept at room temperature during ischemia compared with muscle flaps that were cooled (p < 0.05). Creatinine phosphokinase activity was also increased after 15 minutes of reperfusion in muscle flaps that were not cooled (p < 0.05). Two of the jejunal free flaps had ischemia times of >1 hour and had elevated XO activity after reperfusion despite cooling (p<0.05). Two other jejunal flaps had ischemia times of <1 hour, but in one case, the XO activity was increased before harvest. The other case had no increase in XO activity. Wilkins EG, Rees RS, Smith D, Cashmer B, Punch J, Till GO, Smith DJ Jr. Identification of xanthine oxidase activity following reperfusion in human tissue. Ann Plast Surg 1993;31:60‐65

Organ donation after cardiac determination of death (DCD): a swine model.

Donors after Cardiac Death (DCD) may reduce the organ scarcity; however, their use is limited because of warm ischemia time. Fortunately, this is less important in a subclass of DCD called expected (e-DCD), those with irreversible but incomplete brain injury. This study analyzed hemodynamic/pulmonary data to establish a clinically relevant model of cardiac death that would simulate an e-DCD setting. Hemodynamics, pulmonary artery flows, arterial blood gasses, and left atrial pressure were recorded q 5 minutes in anesthetized swine. After baseline data collection, the ventilator was discontinued and heparin was administered. Cardiac death was defined: as asystole, or mean arterial presusure ≤25 mm Hg with a pulse pressure ≤20 mm Hg. The time to death was approximately 14.8 minutes. Within 5 minutes of removal of the ventilator, there was a hyperdynamic period. Blood gases throughout the apneic time showed a rapid hypercapnia and acidosis. The hyperdynamic reflex response was followed by hypotension, bradycardia, and finally asystole or ventricular fibrillation. The protocol of withdrawal of ventilation, systemic anticoagulation, determination of death was developed to closely resemble the clinical e-DCD scenario. The physiologic changes that happen before death in DCD were described. An e-DCD model that can be used in studies related to organ transplantation was established.

Hospital care of major burns

The burn patient initially requires many of the same measures as any other trauma patient. Both depth and surface extent of the burn injury should be evaluated. Evaluation for smoke inhalation is important, since this is prevalent and life-threatening among burn victims. A treatment plan begins with a realistic appraisal of the probability of survival. Once goals of management have been established, treatment is aimed at both physiologic and aesthetic rehabilitation.