Apparatus and process for detecting a leak during artificial ventilation

A ventilation process for artificially ventilating a patient while the patient is connected to a patient-side coupling unit and while a fluid connection is established between the patient-side coupling unit and a medical device by means of a patient fluid guide unit, the ventilation process comprising the steps of:

• providing a measurement system comprising a sensor arrangement and a sensor fluid guide unit;
• conveying a gas mixture from the medical device through the patient fluid guide unit to the patient-side coupling unit;
• branching off a gas sample from the patient fluid guide unit and guiding the branched off gas sample through the sensor fluid guide unit to the sensor arrangement;
• and
• determining whether an indication of a leak has occurred between the patient fluid guide unit and the sensor arrangement, the determination is made by a monitoring process comprising the steps of:
• for branching off the gas sample from the patient fluid guide unit and guiding the branched off gas sample through the sensor fluid guide unit to the sensor arrangement, at least temporarily producing a negative pressure relative to an environment of the measurement system in at least one of the sensor fluid guide unit and the sensor arrangement;
• by using measured values of the sensor arrangement, determining a thermal conductivity time course as a time course of thermal conductivity of the gas sample which reaches the sensor arrangement;
• and
• as a function of a temporal change of the determined thermal conductivity, determining whether the indication of a leak has occurred between the patient fluid guide unit and the sensor arrangement, wherein the leak establishes a fluid connection between at least one of the sensor fluid guide unit and the environment and the sensor arrangement and the environment.

A measurement system for monitoring artificial ventilation of a patient, wherein the patient is connected to a patient-side coupling unit or is at least temporarily connectable to the patient-side coupling unit, the measurement system comprising:

• a sensor fluid guide unit;
• and
• a sensor arrangement, the sensor arrangement comprising:
• a thermal conductivity sensor;
• and
• a signal processing unit,
• wherein a fluid connection between the patient-side coupling unit and a medical device via a patient fluid guide unit can be established or is established at least temporarily,
• wherein the measurement system is configured to create at least temporarily a negative pressure relative to an environment of the measurement system in at least one of the sensor fluid guide unit and the sensor arrangement,
• wherein the measurement system is configured to branch off a gas sample from the patient fluid guide unit and to guide the branched off gas sample through the sensor fluid guide unit to the sensor arrangement,
• wherein the thermal conductivity sensor is configured to determine a thermal conductivity time course as a time course of the thermal conductivity of the gas sample reaching the sensor arrangement, and
• wherein the signal processing unit is configured to determine, as a function of a temporal change of the determined thermal conductivity, whether an indication of a leak has occurred between the patient fluid guide unit and the sensor arrangement,
• wherein the leak establishes a fluid connection between at least one of the sensor fluid guide unit and the sensor arrangement on the one hand and the environment on the other hand.

A ventilation arrangement for artificial ventilation of a patient, the ventilation arrangement comprising:

• a patient fluid guide unit;
• a patient-side coupling unit configured to be connected to a patient;
• a medical device configured to deliver a gas mixture from the medical device through the patient fluid guide unit to the patient-side coupling unit;
• and
• a measurement system for monitoring artificial ventilation of the patient, the measurement system comprising:
• a sensor fluid guide unit;
• and
• a sensor arrangement, the sensor arrangement comprising:
• a thermal conductivity sensor;
• and
• a signal processing unit,
• wherein a fluid connection between the patient-side coupling unit and the medical device via the patient fluid guide unit can be established or is established at least temporarily,
• wherein the measurement system is configured to create at least temporarily a negative pressure relative to an environment of the measurement system in at least one of the sensor fluid guide unit and the sensor arrangement,
• wherein the measurement system is configured to branch off a gas sample from the patient fluid guide unit and to guide the branched off gas sample through the sensor fluid guide unit to the sensor arrangement,
• wherein the thermal conductivity sensor is configured to determine a thermal conductivity time course as a time course of the thermal conductivity of the gas sample reaching the sensor arrangement, and
• wherein the signal processing unit is configured to determine, as a function of a temporal change of the determined thermal conductivity, whether an indication of a leak has occurred between the patient fluid guide unit and the sensor arrangement,
• wherein the leak establishes a fluid connection between at least one of the sensor fluid guide unit and the environment and the sensor arrangement and the environment.