Abstract: A device and a process detect a leak during artificial ventilation of a patient. A measurement system with a sensor arrangement and a sensor fluid guide unit is monitored. A fluid connection is established between a patient-side coupling unit and a medical device with a patient fluid guide unit. A gas sample is branched off from the patient fluid guide unit and guided through the sensor fluid guide unit to the sensor arrangement. A thermal conductivity time course of the gas sample reaching the sensor arrangement is determined with sensor arrangement measured values. Depending on a temporal change in the determined thermal conductivity, a decision is made as to whether there is an indication of a leak between the patient's fluid-guiding unit and the sensor arrangement. The leak establishes a fluid connection between the sensor fluid guide unit and/or the sensor arrangement and the environment.

Abstract: An infusion pump system comprising means for measuring internal diameter of an associated pump supply tube formed from a flexible material, such as plastic or rubber. The means for measuring internal diameter may comprise an ultrasound system including at least one transmiter and one receiver, as well as an evaluation unit. Alternatively, a mechanical system may be employed in the form of a counterpressure unit arranged perpendicular to the axis of the supply tube and including a movable plunger and an abutment surface for compression of the supply tube to be measured. A measurement and evaluation unit associated with the counterpressure unit determines the distance traversed by the movable plunger. The internal diameter of the tube may be determined by generating a force-displacement diagram. In accordance with one embodiment, the movable plunger is a pumping rod of a linear peristaltic pump.