The Airflow Characteristics in a 3D Airway Model Based on CT Images / 医用生物力学

Objective To discuss the mass transfer of low temperature gas in the lung bronchus, so as to provide a theoretical basis for the implementation of hypothermic ventilation cooling non-heart-beating donor (NHBD) lung program. Methods A real airway model was reconstructed based on human lung CT images, and the computational fluid dynamics (CFD) method was used to investigate the airflow characteristics inside the airway during reciprocating ventilation. The effect of ventilation frequency (0.5, 0.25, 0.125 Hz) on bronchial flow was also studied. Results The flow in the airway showed complex three-dimensional （3D） flow characteristics during reciprocating ventilation. The flow in different areas of the airway was different during inhaling and exhaling; the irregular bronchial geometry had an important effect on its internal flow; when the ventilation frequency decreased from 0.5 Hz to 0.125 Hz, the thickness of flow boundary layer would increase, and the mainstream velocity in different areas of the airway was enhanced to different degrees. Conclusions The real airway model based on CT 3D reconstruction was more accurate than the ideal circularity tube model in showing the bronchial flow. The research findings have an important guiding significance to optimize the hypothermic ventilation cooling NHBD lung technique.

[Renal transplantation using a Maastricht category III non-heartbeating donor: First French experience and review of the literature]. / Transplantation rénale à partir d'un donneur décédé par arrêt circulatoire Maastricht III : première expérience française et revue de la littérature.

In 2015, Annecy Hospital was the first French hospital to perform non-heartbeating organ donation from a Maastricht category III donor (patient awaiting cardiac arrest after withdrawal of treatment). Non-heartbeating organ donation (NHBD), performed in France since 2006, had initially excluded this category, due to ethical questions concerning end of life and treatment withdrawal, as well as technical specificities linked to this procedure. Grenoble University Hospital and Edouard-Herriot Hospital in Lyon then performed the first kidney transplants, with satisfactory outcomes in both recipients. This article presents the details and results of this new experience, challenging both on a deontological and organizational level. Functional outcomes of kidney grafts from NHBD are now well known in the literature and confirm their benefit for patients, with similar results to those from heartbeating donors (HBD). International experiences concerning specifically Maastricht category III NHBD are encouraging and promising.

[Non-heart-beating renal donors: organization in a non-university hospital]. / Prélèvement rénal sur donneur décédé par arrêt cardiaque (DDAC): organisation dans un centre hospitalier non universitaire.

INTRODUCTION: In 2011 in France, all kidneys from patients with brain death and from living donors cannot meet the demand for renal transplants. Since 2006, sampling protocols kidneys from non-heart-beating donors (NHBD) are developed to increase the number of renal transplants. The objective was to describe the organization of a protocol NHBD in a non-university hospital. MATERIALS AND METHODS: Patients with inclusion criteria of protocol NHBD of the Agency of Biomedicine were prospectively included between 1st July 2011 and 31 December 2012. The protocol data were comparable to national data. Vascular canulation was performed by urologists. The epidemiological, clinical and biological characteristics of patients included, the different times and deadlines of the protocol, and data of renal transplantation were collected and analyzed. RESULTS: Over the period of 18 months, 16 patients were included in the protocol NHBD, with a median age of 42 years, and 87.5% of males; 93.8% of patients made a cardiac arrest outside the hospital. The median duration of no-flow was 4.3 minutes (0; 23), the median time between the cardiac arrest and admission to hospital was 90 minutes (0; 116), the median time between the cardiac arrest and the start of the normothermic recirculation was 139 minutes (40; 150), and the median duration of normothermic recirculation was 212 minutes (186; 240). For urologists, the median duration of mobilization was 178 minutes and 97 minutes after 20 h. Twenty-four kidneys were collected (75%) and 22 kidneys were transplanted (91.7%). The median duration of cold ischemia was 9 h 12 (5 h 25; 18 h 02). No primary non-function of graft was observed. Delayed graft function was observed in 50% of cases and the median duration of dialysis was 2 days (0; 19). After 12 months of inclusion, our center accounted for 8% of the national census and 16% of transplanted kidneys NHBD. CONCLUSION: The involvement of rescue, coordination, anesthesiologists and urologists, and the concentration of jobs in our center have helped to minimize response times NHBD in the protocol for maximum quality of kidneys taken with transplant rates and results are very encouraging.

Extracorporeal membrane oxygenation for resuscitation of deceased cardiac donor livers for hepatocyte isolation.

BACKGROUND: Deceased cardiac donors (DCDs) have become a useful source of organs for liver transplantation; nevertheless, there are concerns about the longevity of these grafts. The aim of this study was to evaluate the use of extracorporeal membrane oxygenation (ECMO) to resuscitate DCD porcine livers as a preclinical model using hepatocyte isolation and viability as a marker to assess whole-graft preservation. MATERIALS AND METHODS: We randomized Landrace pigs into three groups after cardiac death and 30 min of warm ischemia: group 1, peritoneal cooling with intravascular cooling for 2 h; group 2, ECMO for 2 h; and group 3, control (conventional intravascular cooling and retrieval). We then reperfused group 1 and 2 livers for 2 h on an ex vivo reperfusion circuit and isolated hepatocytes. RESULTS: After reperfusion, hepatocyte viability was significantly improved in the ECMO group compared to the cooling groups, as measured by trypan blue, methylthiazolyldiphenyl-tetrazolium bromide, and seeding efficiency. Glycogen and reduced glutathione content were significantly used in the ECMO group both before and after reperfusion compared with group 2. The adenosine diphosphate:adenosine triphosphate ratio showed an improved trend (lower) in the ECMO group compared with the cooling group but did not reach statistical significance either before or after reperfusion. CONCLUSIONS: This preclinical study suggests that ECMO is a viable technique for liver preservation that gives an improved yield of hepatocytes when isolated from a DCD liver, suggesting improved liver preservation.

SIMPLE MACHINE PERFUSION SIGNIFICANTLY ENHANCES HEPATOCYTE YIELDS OF ISCHEMIC AND FRESH RAT LIVERS.

The scarcity of viable hepatocytes is a significant bottleneck in cell transplantation, drug discovery, toxicology, tissue engineering, and bioartificial assist devices, where trillions of high-functioning hepatocytes are needed annually. We took the novel approach of using machine perfusion to maximize cell recovery, specifically from uncontrolled cardiac death donors, the largest source of disqualified donor organs. In a rat model, we developed a simple 3 hour room temperature (20±2°C) machine perfusion protocol to treat non-premedicated livers exposed to 1 hour of warm (34°C) ischemia. Treated ischemic livers were compared to fresh, fresh-treated and untreated ischemic livers using viable hepatocyte yields and in vitro performance as quantitative endpoints. Perfusion treatment resulted in both a 25-fold increase in viable hepatocytes from ischemic livers, and a 40% increase from fresh livers. While cell morphology and function in suspension and plate cultures of untreated warm ischemic cells was significantly impaired, treated warm ischemic cells were indistinguishable from fresh hepatocytes. Further, a strong linear correlation between tissue ATP and cell yield enabled accurate evaluation of the extent of perfusion recovery. Maximal recovery of warm ischemic liver ATP content appears to be correlated with optimal flow through the microvasculature. These data demonstrate that the inclusion of a simple perfusion-preconditioning step can significantly increase the efficiency of functional hepatocyte yields and the number of donor livers that can be gainfully utilized.

Postmortem and ex vivo carbon monoxide ventilation reduces injury in rat lungs transplanted from non-heart-beating donors.

OBJECTIVE: We sought to determine whether ventilation of lungs after death in non-heart-beating donors with carbon monoxide during warm ischemia and ex vivo lung perfusion and after transplant would reduce ischemia-reperfusion injury and improve lung function. METHODS: One hour after death, Sprague-Dawley rats were ventilated for another hour with 60% oxygen (control group) or 500 ppm carbon monoxide in 60% oxygen (CO-vent group; n=6/group). Then, lungs were flushed with 20 mL cold Perfadex, stored cold for 1 hour, then warmed to 37 °C in an ex vivo lung perfusion circuit perfused with Steen solution. At 37 °C, lungs were ventilated for 15 minutes with alveolar gas with or without 500 ppm carbon monoxide, then perfusion-cooled to 20 °C, flushed with cold Perfadex and stored cold for 2 hours. The left lung was transplanted using a modified cuff technique. Recipients were ventilated with 60% oxygen with or without carbon monoxide. One hour after transplant, we measured blood gases from the left pulmonary vein and aorta, and wet-to-dry ratio of both lungs. The RNA and protein extracted from graft lungs underwent real-time polymerase chain reaction and Western blotting, and measurement of cyclic guanosine monophosphate by enzyme-linked immunosorbent assay. RESULTS: Carbon monoxide ventilation begun 1 hour after death reduced wet/dry ratio after ex vivo lung perfusion. After transplantation, the carbon monoxide-ventilation group had better oxygenation; higher levels of tissue cyclic guanosine monophosphate, heme oxidase-1 expression, and p38 phosphorylation; reduced c-Jun N-terminal kinase phosphorylation; and reduced expression of interleukin-6 and interleukin-1ß messenger RNA. CONCLUSIONS: Administration of carbon monoxide to the deceased donor and non-heart-beating donor lungs reduces ischemia-reperfusion injury in rat lungs transplanted from non-heart-beating donors. Therapy to the deceased donor via the airway may improve post-transplant lung function.

Anesthesia for liver transplantation from a maastricht category 4 non-heart-beating donor -A case report-.

Great improvements in patient selection, surgical techniques, perioperative care, and immunosuppression have been made for the optimization of liver transplantation. To increase the number of organs available for liver transplantation, transplant centers have used marginal donors, split livers, living donors, or non-heart-beating donors (NHBDs). Despite recent enthusiasm for NHBDs in liver transplantation, warm ischemic injury to recovered organs has been an obstacle for the wide acceptance of NHBD. In the present case, we have conducted a liver transplantation from a Maastricht Category 4 NHBD. Warm ischemic time was 20 minutes and cold ischemic time was 5 hour 43 minutes. Consequently, the liver was successfully transplanted into the recipient.

Anesthesia for liver transplantation from a maastricht category 4 non-heart-beating donor: A case report / 대한마취과학회지

Great improvements in patient selection, surgical techniques, perioperative care, and immunosuppression have been made for the optimization of liver transplantation. To increase the number of organs available for liver transplantation, transplant centers have used marginal donors, split livers, living donors, or non-heart-beating donors (NHBDs). Despite recent enthusiasm for NHBDs in liver transplantation, warm ischemic injury to recovered organs has been an obstacle for the wide acceptance of NHBD. In the present case, we have conducted a liver transplantation from a Maastricht Category 4 NHBD. Warm ischemic time was 20 minutes and cold ischemic time was 5 hour 43 minutes. Consequently, the liver was successfully transplanted into the recipient.

The Feasibility of Recovered Warm Ischemic Injury on Non-heart-beating Donor Liver by Hepatocyte Growth Factor in Animal Model / 대한이식학회지

PURPOSE: Liver transplantation is the therapy of choice for patients with acute and acute-on-chronic severe liver failure or hepatocellular carcinoma. But a suitable liver is not always available for transplantation due to limited donor numbers. To increase the number of available liver for transplantation, a non-heart-beating donor (NHBD) liver transplant program is started. In NHBD liver transplantation, warm ischemic injury of liver occurs. The duration of warm ischemia is thought to be the most important risk factor for postoperative complications such as primary nonfunction or severe hepatic dysfunction. Recent evidence indicates that hepatocyte growth factor (HGF) plays an important role as a cytoprotector against hepatic injury by anti-apoptotic effect and mitogen in liver regeneration. Therefore studies also were performed to examine whether HGF influenced the viability and regeneration of hepatocytes from rats, subjected to prolonged warm ischemic injury. METHODS: Male Sprague- Dawley rats were subjected to non-heart-beating death by cervical spine fracture. Rats left in room temperature directly after, 30-minutes, 1-hours before surgery and perfusion was performed for isolating hepatocyte. Among three groups, hepatocyte viability was compared by trypan blue stain. And isolated hepatocytes from 30-minutes warm ischemic group were cultured for 24-hours, which were treated with no HGF and addition of various doses (5 ng/mL, 10 ng/mL, 20 ng/ mL, 40 ng/mL, 100 ng/mL) of HGF. Anti-apoptosis and regeneration of hepatocyte were compared by LDH assay, MTS assay, western blot, and immunocyto-chemistry after a 24-hours culture. RESULTS: The results of hepatocyte viability along the prolonged warm ischemic groups in isolated hepatocytes decreased sequentially 74.8+/-12.6%, 45.0+/-5.4%, 37.8+/-10.4% along directly after, 30-minutes, 1-hours in trypan blue stain (P<0.01). And 24-hour-cultured hepatocytes from 30-minutes warm ischemic group were treated with HGF. The results of LDH assay, MTS assay did not have relation with HGF addition. But the results of western blot and immunocytochemistry shown that HGF doses dependent anti-apoptosis and regeneration of hepatocyte increased. That indicates HGF presumably inhibites apoptotic pathway by phosphorylation. And HGF also makes hepatocyte hypertrophy and albumin synthesis. CONCLUSION: HGF was a potent cytoprotector against hepatic injury by anti- apoptotic effect and mitogen of liver regeneration in NHBD liver animal model. HGF facilitates recovery of the liver from prolong warm ischemic injury. If the more clinical studies and large animal studies are performed, NHBD using liver transplantation will be available with more chances by HGF.