The logfile of the device in question was not available for investigation.However, based on the transmitted information, a ¿v002 - zero position invalid¿ code was found in the log.This entry is generated when it is not possible to zero the ventilator position encoder and points to an issue with the light barrier cable or ventilator assembly.A dräger fse has replaced the light barrier cable and ventilator motor in follow-up of this case.The device was tested, performed according to specifications and could be returned to use.There have been no further problems reported.The replaced material was not made available to the manufacturer for investigation.Hence, a detailed root cause analysis is not possible.The device was in operation for more than 14 years.The motor is designed for a lifetime of ten years at standard operating conditions (5hours/day, 5 days/week).A wear-and-tear related end of life for this component can be considered well-acceptable.Dräger finally concludes that the device responded as designed upon a detected deviation.If it is not possible to adjust the zero point of the position encoder, this may lead to erroneous motor control signals.To prevent from serious damages, the device software shuts down automatic ventilation and triggers a corresponding alarm to alert the user.Manual ventilation remains possible.No patient consequences have occurred.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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