Based on the device log analysis it was found that on the reported date of event a faulty bag pressure sensor was detected during the system test.The offset voltage of the bag pressure sensor was found to be out of specification.The bag pressure sensor monitors the filling volume of the breathing bag connected to the breathing system and provides information concerning the available volume for inspiration.Therefore, automatic ventilation cannot be started if a faulty pressure sensor is detected during the system test.As initially reported a ventilator failure occurred during use.This could not be confirmed by means of the log records.Even if the bag pressure sensor did fail during use, a ventilator failure would not be the consequence; a sensor drift might lead to incorrect alarm priorities (fresh gas deficit alarms of cascaded priority are triggered by this pressure sensor) as well as a faulty econometer level.However, fresh gas dosage is not affected and independent from the pressure signal, additional pressure- and flow-related alarms are given in case of an actual fresh gas deficit.The filling level of the breathing bag is further visible to the user.Finally, it can be concluded that the device reacted as specified by detecting the faulty pressure sensor during the system test.In this state automatic ventilation cannot be activated.The pressure sensor was replaced and the unit can be put back into operation.It can be concluded that based on the investigation results the case is assessed as non-reportable and should not have been reported initially.
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