Process and device for detection of a leak in a ventilation circuit

A measuring system for a mechanical ventilation of a patient, the measuring system comprising:

• a gas sensor array;
• a gas sensor fluid-guiding unit connected or connectable to a patient-side fluid-guiding unit, wherein, using the patient-side fluid-guiding unit, a fluid connection is established or establishable, the fluid connection configured to be between the patient and a medical device, wherein the patient is mechanically ventilated while a process for monitoring the measuring system is performed,
• wherein the measuring system is configured to suction gas from the patient-side fluid-guiding unit through the gas sensor fluid-guiding unit to the gas sensor array,
• wherein the gas sensor array is configured to measure a concentration of a gas flowing in the fluid connection between the patient and the medical device;
• a control device, wherein the control device is configured to automatically control a parameter of the mechanical ventilation as a function of the concentration of the gas;
• and
• a signal processing unit configured to:
• calculate an indicator of progress over time of a concentration of carbon dioxide, as a carbon dioxide concentration time curve, in the suctioned gas sample using measured values of the gas sensor array;
• calculate an indicator of progress over time of a concentration of an other gas, different from carbon dioxide, as an other gas concentration time curve, in the suctioned gas sample using measured values of the gas sensor array;
• calculate an indicator of a progress over time of a temporal change of the carbon dioxide concentration, as a carbon dioxide concentration change curve, using the carbon dioxide concentration time curve;
• calculate an indicator of a progress over time of a temporal change of the concentration of the other gas, as an other gas concentration change curve, using the other gas concentration time curve;
• search for time periods with a same sign, wherein throughout the same sign time period the two concentration change curves have the same sign, with both concentration change curves being greater than zero or both less than zero;
• upon detecting at least one same sign time period, check whether the two concentration change curves meet a predefined first leak criterion in the detected at least one same sign time period;
• upon the predefined first leak criterion being met, determining that a leak has occurred between the patient-side fluid-guiding unit and the gas sensor array or determining that there is an indication of such a leak,
• wherein the control device is configured to generate an alarm if the signal processing unit determines that the leak has occurred or that there is the indication of the leak and to transmit the alarm to a receiver and to provide the alarm as output such that the alarm is configured to be perceptible to a person, and
• wherein the mechanical ventilation is configured to be continued without using the results of the gas measurement of the concentration of the gas flowing in the fluid connection between the patient and the medical device if the signal processing unit determines that the leak has occurred or that there is the indication of the leak.

A connection device for mechanical ventilation of a patient,

• the connection device comprising:
• a patient-side fluid-guiding unit;
• and a measuring system comprising:
• a gas sensor array;
• a gas sensor fluid-guiding unit connected or connectable to the patient-side fluid-guiding unit, wherein, using the patient-side fluid-guiding unit, a fluid connection is established or establishable, the fluid connection configured to be between the patient and a medical device, and whereby the patient is mechanically ventilated while a process for monitoring the measuring system is performed,
• wherein the measuring system is configured to suction gas from the patient-side fluid-guiding unit through the gas sensor fluid-guiding unit to the gas sensor array,
• the gas sensor array being configured to measure a concentration of a gas flowing in the fluid connection between the patient and the medical device;
• a control device, wherein the control device is configured to automatically control a parameter of the mechanical ventilation as a function of the concentration of the gas;
• and a signal processing unit configured to:
• calculate an indicator of progress over time of a concentration of carbon dioxide with respect to time, as a carbon dioxide concentration time curve, in the suctioned gas sample using measured values of the gas sensor array;
• calculate an indicator of progress over time of a concentration of an other gas, different from carbon dioxide, as an other gas concentration time curve, in the suctioned gas sample using measured values of the gas sensor array;
• calculate an indicator of a progress over time of a temporal change of the carbon dioxide concentration, as a carbon dioxide concentration change curve, using the carbon dioxide concentration time curve;
• calculate an indicator of a progress over time of a temporal change of the concentration of the other gas, as an other gas concentration change curve, using the other gas concentration time curve;
• search for time periods with a same sign, wherein throughout the same sign time period the two concentration change curves have the same sign, with both concentration change curves being greater than zero or both less than zero;
• upon detecting at least one same sign time period, check whether the two concentration change curves meet a predefined first leak criterion in the detected at least one same sign time period;
• and
• upon the predefined first leak criterion being met, determine that a leak has occurred between the patient-side fluid-guiding unit and the gas sensor array or determine that there is an indication of such a leak;
• wherein the control device is further configured to generate an alarm if the signal processing unit determines that the leak has occurred or that there is the indication of the leak and to transmit the alarm to a receiver and to provide the alarm as output such that the alarm is configured to be perceptible to a person;
• and wherein the mechanical ventilation is continuable or continued without using the results of the gas measurement of the concentration of a gas flowing in the fluid connection between the patient and the medical device if the signal processing unit determines that the leak has occurred or that there is the indication of the leak.

A medical system comprising:

• a medical device;
• and a connection device comprising:
• a patient-side fluid-guiding unit;
• and
• a measuring system comprising:
• a gas sensor array;
• a gas sensor fluid-guiding unit connected to or connectable to the patient-side fluid-guiding unit,
• wherein, using the patient-side fluid-guiding unit, a fluid connection is establishable, the fluid connection configured to be between the patient and the medical device, and whereby the patient is mechanically ventilated while a process for monitoring the measuring system is performed,
• wherein the measuring system is configured to suction gas from the patient-side fluid-guiding unit through the gas sensor fluid-guiding unit to the gas sensor array, wherein the measuring system is configured to measure a concentration of a gas flowing in the fluid connection between the patient and the medical device;
• and a signal processing unit configured to:
• calculate an indicator of a progress over time of a concentration of carbon dioxide, as a carbon dioxide concentration time curve, in the suctioned gas sample using measured values of the gas sensor array;
• calculate an indicator of a progress over time of a concentration of an other gas, different from carbon dioxide, as an other gas concentration time curve, in the suctioned gas sample using measured values of the gas sensor array;
• calculate an indicator of a progress over time of a temporal change of the carbon dioxide concentration, as a carbon dioxide concentration change curve, using the carbon dioxide concentration time curve;
• calculate an indicator of a change over time of a temporal change of the concentration of the other gas, as an other concentration change curve, using the other gas concentration time curve;
• search for time periods with a same sign, wherein during the same sign time period the two concentration change curves have the same sign throughout the same sign time period, with both concentration change curves being greater than zero or both less than zero;
• upon detecting at least one same sign time period, check whether the two concentration change curves meet a predefined first leak criterion in the detected at least one same sign time period;
• and
• upon the predefined first leak criterion being met, determine that a leak has occurred between the patient-side fluid-guiding unit and the gas sensor array or determine that there is an indication of such a leak, wherein the medical device is configured:
• to receive from the measuring system of the connection device measured time curves of the carbon dioxide concentration and of the concentration of the other gas;
• and
• at least one of:
• to process the received time curves, and to output the received time curves in a form configured to be perceptible by a person;
• a control device,
• wherein the control device is configured to automatically control a parameter of the mechanical ventilation as a function of the concentration of the gas;
• wherein the control device is further configured to generate an alarm if the signal processing unit determines that the leak has occurred or that there is the indication of the leak and to transmit the alarm to a receiver and to provide the alarm as output such that the alarm is configured to be perceptible to a person;
• and
• wherein the mechanical ventilation is continued without using the results of the gas measurement of the concentration of the gas flowing in the fluid connection between the patient and the medical device if the signal processing unit determines that the leak has occurred or that there is the indication of the leak.