Patent ID: 9656012
Date: 2017-05-23
CPC Classifications: A61M

Claim:
1. A method of determining an operating parameter of a device for extracorporeal blood treatment as a function of absolute pressure, said method comprising the following steps: setting ambient pressure in a closed container filled at least partially with an initial air volume or in a closed container filled at least partially with an initial air volume and at least partially with a liquid; delivering a fluid to the closed container which is filled at least partially with the initial air volume by a sequence of at least two delivery strokes of a delivery device having predetermined stroke volumes, or delivering a fluid from the closed container filled at least partially with the initial air volume and at least partially with the liquid by a sequence of at least two delivery strokes of a delivery device with the predetermined stroke volumes; calculating a total volume delivered after each delivery stroke; measuring a relative pressure in the container after each delivery stroke; assigning the total volume delivered after each completed delivery stroke and the measured volume of the relative pressure in the container after each completed delivery stroke to a value pair for the delivery stroke completed; determining the absolute ambient pressure and determining the initial air volume in the container using the value pairs for the sequence of delivery strokes completed; and calculating the operating parameter as a function of the determined absolute ambient pressure, the absolute ambient pressure and the initial air volume in the container being calculated using an equation system based on the Boyle-Mariotte law for changes in state of the air volume in the container, the equation system providing that such that in the equation system: P P V V n denotes the total number of delivery strokes of the delivery device, and i denotes a running index for the number of delivery strokes.