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Based on the analysis of the device logfile, the case could be reconstructed.It was found that the device detected a wrong motor position.In such case, to protect from potentially hazardous output and/or from serious damages to the ventilator unit, the device is designed to shut down automatic ventilation and to post a corresponding alarm.Manual ventilation is further available as well as the monitoring functions of the device are.It was further reconstructed that the user continued therapy by using manual ventilation until the device was restarted by the user.After successful completion of the power- on self-test (post), therapy was continued using pressure support mode without any further issues.The log analysis revealed no indications for a general motor- or motor control problem.Since there were no problems observed during piston referenciation during post either, a motor failure seems unlikely.Thus, most likely foreign objects in the light barrier or a contaminated encoder disc was disturbing the correct detection of the motor position and in consequence to the reported symptom.Dräger finally concludes that the device behaved as specified upon the detected issue; no patient consequences have been reported.The device was inspected in follow-up to the event and no indications for a technical device failure were found either.After testing, the device was returned back to use, and no further problems have been reported.The number of similar cases, related to the same phenomenon, is within the expected range of the respective risk assessment and thus accepted.
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