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.

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.