A review of the literature on ligation of the portal vein has been presented. A brief survey of the literature on the ligation of the hepatic veins and the hepatic artery has been included. The review reveals that while there is no disagreement that the result of sudden acute ligation of the portal vein in dogs is inevitably death, there is disagreement as to the cause of death. The main theories are (i) that exsanguination into the splanchnic vascular bed occurs, (ii) that the loss of blood is insufficient to cause death, and that other factors must be implicated, the "toxic" theory. The species difference in the effects of ligation appears to lie in the degree of porto-systemic venous anastomoses. The experiments described in this thesis were performed with the dog as the experimental animal. A measurement of the decrease in circulating blood volume following ligation of the portal vein, using the "labelled" red cell method, was made. It was considered that valid consecutive estimations of blood volume could be made using the "labelled" red cell method. With 11 dogs, 30 minutes after portal vein ligation, the decrease amounted to 57.9% of the original blood volume. The measurement of the normal splanchnic vascular blood volume was made using 10 dogs. This amounted to 21.7% of the circulating blood volume, or 17.7 ml. per kilogram body weight. As the total vascular bed had been reduced by the exclusion of this splanchnic portion, the smaller circulating blood volume was required to serve a smaller vascular area, and it was considered that the true decrease in circulating blood volume was therefore 44.8%. It was considered that this amount of blood loss was not adequate to account for the inevitability of death, or the short period of survival (79.7 minutes) when compared to the effects of bleeding comparable quantities of blood, or bleeding to comparable levels of blood pressure. Haematocrit estimations were made on the systemic arterial blood and portal venous blood before and after ligation of the portal vein. There was a significant decrease in the systemic arterial haematocrit, and rise in the portal venous haematocrit. By the injection of latex into the portal vein of 3 dogs, the main porto-systemic venous anastomoses were found to occur in relation to the vagus nerves at the lower end of the oesophagus. Other porto-systemic venous anastomoses were of minor importance. It was not possible to influence the outcome of acute portal vein ligation by splenectomy, or by antibiotics under the conditions of the experiments. / Medicine, Faculty of / Graduate

There have been numerous reports of cardiovascular and pulmonary abnormalities in patients with cirrhosis and portal hypertension. The role of portal hypertension in the pathogenesis of pulmonary abnormalities in patients with liver disease has not been defined. The present study was therefore undertaken to clarify this. Pulmonary function, including exercise testing, was evaluated in two groups of patients, 11 with portal hypertension due to cirrhosis and 10 with extrahepatic portal vein thrombosis and normal liver histology. Carbon monoxide gas transfer (TLCOsb) was less than 75% of predicted values in four patients from each group. One patient from each group had clinical and catheter confirmed evidence of pulmonary hypertension. Abnormal cardiorespiratory responses to exercise occurred in three patients in the extrahepatic group. Two had associated low TLCOsb and one developed arterial desaturation on exercise. A similar pattern was seen in three patients with cirrhosis. All had low TLCOsb and one developed arterial desaturation during exercise. In the cirrhotic group however three additional patients showed reduction in Pa02 unassociated with elevated heart rate response on exercise. There was no significant correlation with the presence of autoimmune antibodies which appear to be a secondary phenomenon. Our results suggest that pulmonary hypertension is linked to the presence of portal hypertension. Reduction in arterial P02, appears to occur only in patients with liver disease, presumably on the basis of intrapulmonary shunting.

Thesis (PhD) - Swinburne University of Technology, 2008. / Submitted for the degree of Doctor of Philosophy, Swinburne University of Technology - 2008. Typescript. Includes bibliographical references (p.271-304).

Tese de mestrado. Faculdade de Engenharia. Universidade do Porto. 1998

Estágio realizado no INEGI e orientado pelo Eng.º Nuno Ramos / Tese de mestrado integrado. Engenharia Informátca e Computação. Faculdade de Engenharia. Universidade do Porto. 2008

The patient portal, a Health Information Technology (HIT) tool, was created to help patients become engaged with their health and health information to improve health outcomes. The practice problem was the low patient portal use and lack of nurses' knowledge of patient HIT tools at an urban ambulatory clinic in the northeastern United States. The practice-focused question explored whether an educational intervention with the care coordination team (CCT) would increase prescription refill requests and facilitate patient-provider communications via the patient portal. The 2 frameworks used for the project were Knowles's adult learning theory and Lewin's theory of change. The preintervention data were collected from an electronic-medical-record-generated report that provided portal usage for the 6 months prior to the intervention. The CCT members were trained on teaching and modeling portal use from the perspective of the patients. A checklist of steps was created and given to the CCT to be used in patients' education. Postintervention reports showed that the patient portal usage for patient-provider communication increased by 165%. The prescription refill requests did not show an increase because medication used to treat chronic conditions were typically supplied for 6 months. The implications of this project for social change include the potential for providers to improve how they interact with their patients by incorporating patient portal education inpatient visits.

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No description available.

The increasing use of intensity modulated radiation therapy (IMRT) to deliver conformal radiation treatment has prompted the search for a faster and more cost effective quality assurance (QA) system. The standard technique relies on the use of film for two-dimensional dose distribution verification. Although film is considered the gold standard and is widely used for this purpose, the procedures involved are relatively lengthy, labour intensive and costly for a multiple field IMRT verification. In this study, we investigate the use of an amorphous silicon electronic portal imaging device (a-Si EPID) to complement the film. The dosimetric behaviour of the device is studied both experimentally and numerically using the EGSnrc Monte Carlo simulation routine. The intrinsic build-up of the flat panel EPID was found to be 1.1 cm of water equivalent material. The response of the flat panel EPID was found to be linear between 0 and 300 cGy. To calibrate the flat panel EPID for two dimensional dose measurements, the deconvolution method was chosen. The scatter dose kernel required for this calibration method was calculated and characterized by varying the energy, spectrum and phantom material using a 6MV pencil beam. We found that flat panel EPID scatter kernel has as much as 80% more scattering power than the water scatter kernel in the region 1 cm away from the center of a 6MV pencil beam. This confirms that a flat panel EPID behaves significantly differently from water dosimetrically and requires an accurate dose scatter kernel for calibration. A 1.0 cm wide picket fence test pattern was used to test the accuracy of the kernel. Using the deconvolution method with the calculated dose kernels, the measurements from the flat panel EPID show improved agreement with the films.

No description available.