METHOD FOR INITIALIZING A DEVICE FOR BLOOD TREATMENT IN SINGLE-NEEDLE MODE, AND DEVICE FOR BLOOD TREATMENT IN SINGLE-NEEDLE MODE

摘要

The invention relates to a device and a method for blood treatment in single-needle mode. The blood treatment device comprises an extracorporeal blood circuit (1), which has a blood delivery line (8) leading to the inlet of a blood treatment unit (2), and a blood return line (9) issuing from the outlet of the blood treatment unit. In the blood return line, there are means (11) for collecting blood, for example a blood collection container, which are in fluid communication with gas storage means (18), for example an air storage container. The fluid communication is used 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 according to the invention and the device according to the invention are based on the calculation of a pressure (p_{air storage max}), which is established in the gas storage means before the initiation of the arterial and venous phases. The level of this maximum pressure is such that air cannot under any circumstances enter the patient. Two boundary conditions are taken into consideration in calculating the pressure. First, the pressure should be low enough to ensure that infusion of air into the patient is excluded and that the flow is still regulated even at counter-pressures lower than the ambient pressure. Second, the pressure should be high enough to provide a sufficiently large air mass to displace the blood from the blood collection means to the gas storage means.