Log file evaluation performed by the manufacturer confirms the reported behavior: the supervisor function detected a sporadic loss of the signal from the sensor that monitors the pressure inside the cylinder of the piston ventilator.To protect the patient from potentially hazardous output the device is designed to shut-down automatic ventilation and to post a corresponding alarm to alert the user.Manual ventilation with the built-in breathing bag remains possible; the monitoring functions are still available as well.As confirmed for the particular case the device indicates when the signal of the pressure sensor is being detected again and automatic ventilation would be availble - the user could continue with automatic ventilation one minute later.It could not be determined by log file analysis what the exact root cause for the sporadic signal loss of the sensor was.The device was tested in follow-up of the event and did not exhibit any persisting malfunction.A reasonable explanation would be that humidity in the breathing gas has disturbed the function of the sensor for a short time.Dräger finally concludes that the workstation responded as designed upon the deviation.The number of similar cases, related to the same root cause, is within the expected range of the respective risk assessment and thus accepted.
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