Preoperative biliary drainage in severely jaundiced patients with pancreatic head cancer: A retrospective cohort study

Background: Guidelines recommend against preoperative biliary drainage (PBD) in patients with pancreatic head cancer if bilirubin levels are = 250 and = 250 versus = 250. PBD technical success (83% vs. 81%, p = 0.80) and PBD related complications (33% vs. 29%, p = 0.60) did not differ between these groups. Analyzing bilirubin levels >= 250 versus = 250 and < 250. Our study does not support a different approach regarding PBD in patients with severe jaundice.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Preoperative biliary drainage in severely jaundiced patients with pancreatic head cancer: A retrospective cohort study

Background: Guidelines recommend against preoperative biliary drainage (PBD) in patients with pancreatic head cancer if bilirubin levels are <250 μmol/l. However, patients with higher bilirubin levels undergo PBD, despite the lack of supporting evidence. This study aims to evaluate outcomes in patients with a bilirubin level ≥250 and < 250. Methods: Patients were identified from databases of 3 centers. Outcomes were compared in patients with a bilirubin level ≥250 versus <250 both at the time of diagnosis and directly prior to surgery. Results: 244 patients were included. PBD was performed in 64% (123/191) with bilirubin <250 at diagnosis and 91% (48/53) with bilirubin ≥250. PBD technical success (83% vs. 81%, p = 0.80) and PBD related complications (33% vs. 29%, p = 0.60) did not differ between these groups. Analyzing bilirubin levels ≥250 versus <250 directly prior to surgery, no differences in severe postoperative complications and mortality were found. Conclusions: In patients with a pancreatic head cancer, PBD technical success and complications, and severe postoperative complications did not differ between patients with a bilirubin level ≥250 and < 250. Our study does not support a different approach regarding PBD in patients with severe jaundice

Die lagerlose Pumpe für hohe Fluidtemperaturen

Bearingless motors consist of a drive system with an integrated magnetic bearing and are used in centrifugal pumps for high purity applications. The machine is constructed without the use of a drive shaft, dynamic seals, and conventional mechanical bearings, since the rotor is levitated in a magnetic field. This allows for a wear-free operation and prevents the contamination of process fluids. Bearingless pumps are employed in wet chemical etching processes in the semiconductor industry, since low contamination is required due to the small structures on the wafer. The reaction speed of etching processes depends strongly on the temperature of the used chemicals. Therefore, high fluid temperatures are required in order to increase processing speed and yield. State of the art, commercially available bellows pumps are rated for 210 °C and bearingless pumps can be used for fluid temperatures of 90 °C with passive air cooling and 180 °C with active water cooling. This work is focused on increasing the admissible fluid temperature of a passively cooled bearingless pump to 250 °C. The number of components and, therefore, the complexity, the cost and the probability of failure are minimized by omitting an active cooling system. Challenges include the appropriate choice of materials, the construction of the components and the development of a sensing and closed-loop control scheme for high temperatures. The temperature distribution in the pump is calculated by using a thermal model, which is based on the analysis of the temperature-dependent performance of the bearingless pump, the internal losses and the heat transfer mechanisms. The choice of materials and the construction of the pump are based on the results of the thermal model. The motor utilizes a novel closed-loop, angle sensorless control scheme for bearingless machines. The rotor angle is obtained with a two-stage estimator consisting of a model-based low-speed and a back electromotive force-based high-speed angle observer. The controller enables closed loop operation at all rotational speeds and at standstill. Two prototypes of the bearingless high temperature pump were constructed and manufactured. Both machines were tested with fluid temperatures of up to 250 °C without failure of components. This proves that bearingless pumps can be employed successfully in extreme temperature applications

Preoperative biliary drainage in severely jaundiced patients with pancreatic head cancer: A retrospective cohort study

Background: Guidelines recommend against preoperative biliary drainage (PBD) in patients with pancreatic head cancer if bilirubin levels are = 250 and = 250 versus = 250. PBD technical success (83% vs. 81%, p = 0.80) and PBD related complications (33% vs. 29%, p = 0.60) did not differ between these groups. Analyzing bilirubin levels >= 250 versus = 250 and < 250. Our study does not support a different approach regarding PBD in patients with severe jaundice