Method for initializing a device for blood treatment in single-needle operation and device for blood treatment in single-needle operation

摘要

The invention relates to a device and a method for blood treatment for the single-needle operation. The blood treatment device has an extracorporeal blood circuit (1) which has a blood supply line (8) leading to the inlet of a blood treatment unit (2) and a blood return line (9) leaving the outlet of the blood treatment unit. Arranged in the blood return line are means (11) for collecting blood, for example a blood collection container, which are in fluid communication with means (18) for storing gas, for example an air storage container. The flow connection serves to transfer gas from the air storage container into the blood collection container and to transfer gas from the blood collection container into the air storage container. The method and the device according to the invention are based on the calculation of a pressure (pLuftspeicherMax) which is set in the means for storing gas before the introduction of the arterial and venous phases. This maximum pressure is such that air can not enter the patient under any circumstances. When calculating the pressure, two boundary conditions are taken into account. On the one hand, the pressure should be small enough to ensure that both an air infusion into the patient is excluded as well as at a backpressure, which are smaller than the ambient pressure, nor a flow control is ensured. On the other hand, the pressure should be high enough to be able to provide a sufficiently large air mass for the displacement of the blood from the means for collecting blood in the means for storing gas.