[Haemodialysis in acute renal failure; technique and surveillance (author's transl)].

Access to the blood stream for haemodialysis is generally via an arterio-venous shunt. Experience has shown that the introduction of two Shaldon catheters (with a modified Seldinger technique) into the upper caval system does not require special surgical knowledge and shortens and simplifies the preparations for haemodialysis in acute renal failure. As the catheters can easily be changed over guide wires, correction of obstructions and bacteriological examinations of the catheter tips do not present a problem. There were no complications. With this simplified access the acute stage of renal failure can be bridged for up to 6--8 weeks. The diameter of the catheters ensures an adequate flow of 150--200 ml/min. In vitro tests with a modified catheter (not yet available commercially) established 1. that the flow rate could be increased by 45 percent without altering the pressure of the return flow, and 2. that its use did not increase the rate of haemolysis. Incorrect placing of the catheters--the venous limb should be higher, i.e. nearer the heart, than the "arterial" catheter--may raise the re-circulating fraction by 6--18 percent. Since heparinization is necessary for haemodialysis but carries the grave risk of haemorrhages, espeically in the patients of an intensive care unit, it is essential to provide the means for estimating partial thromboplastin time at the bed side. This allows the heparin doses to be sufficiently reduced to obviate haemorrhage during and after haemodialysis.