It was reported that, while in use, the device shut down with motor failure, posted an according alarm and changed into safety mode.There was no injury to the patient.
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The involved device was exhibiting a similar problem at an earlier occasion already - the case was reported under reference 9611500-2018-00045.The failure of stop of automatic ventilation could be confirmed but it was neither possible to duplicate it nor to narrow it down to a specific root cause at that time.The motor assembly and parts of the position detection system had been replaced as a precaution.After recurrence of the problem the entire device was returned to manufacturer for evaluation and was subject to in-depth testing.It could be revealed from the logs that the device forced a safety stop of automatic ventilation due to the fact that the motor spindle was moved into end position inside the piston.The error was related to a problem with the motor controller board, in particular with the position detection electronics.In consequence, the motor received wrong control signals on a continuous base.The divergence between expected spindle position and the real one increased successively until the safety stop position was reached.The respective motor controller board was replaced which has put the device back into fully operable condition.Dräger concludes that the device responded as designed upon the malfunction of a single electronic subsystem.The automatic ventilation was stopped to prevent from serious mechanical damages to the ventilator unit.The device has alarmed and switched autonomously to manual ventilation mode in which it was used for several more minutes until a replacement device was made available.No patient consequences have reportedly 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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