It was reported that during start of the anesthesia, after pre-oxygenation of the patient, it appeared that the anesthesia workstation failed to deliver oxygen.The patient saturation level decreased to 45 % for a short term.The patient was disconnected from the anesthesia workstation and manually ventilated.Manufacturer's reference #: (b)(4).
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The anesthesia workstation (hereafter named system) was tested by the user facility.The system passed the system checkout and no deviations were found.No parts were replaced.The system device logs were sent for evaluation.Evaluation of the received test log shows that successful system checkouts were performed prior to and after the event.The technical log has no entry that would indicate a technical failure in the system at the time of the event.The trend log is not available as the logs were saved more than 24 hours after the event.The treatment period when the reported event occurred was started at 11:35, in adult patient category and ventilation type set to manual ventilation.The o2 concentration was set to 100%.At 11:40, the ventilation type was set to automatic ventilation in volume control and agc (automatic gas control) was activated and the set fio2 target was set to 40%.The lower alarm limits for fio2 was set to 25% o2.Alarms for expiratory minute volume low, respiratory rate low and a few alarms for etco2 low were generated.At 11:44, the ventilation type was set to manual ventilation and the o2 concentration was increased in steps to 98 %.At 11:47, ventilation type was set to automatic ventilation in volume control and agc was activated with fio2 target set to max.Alarm for respiratory rate high was generated.The ventilation type was set to manual ventilation for a few seconds and then back to automatic ventilation and a few minutes later the agc target fio2 was decreased to 40%.The treatment continued after this until 12:36, when the treatment was ended and the system set to standby.The summary of the log evaluation is that the ventilation type was changed a few times in the beginning of the treatment and some alarms were generated around the given time of the event.There was no frequent alarm situation and there was no alarms for fio2 low or low o2 supply pressure low during the treatment.There is no indication of a technical failure in the system at the time of the event.Our conclusion, based on the user facility investigation on-site and the log evaluation, is that there was no technical failure in the system at the time of the event.The cause of the reported event has not been determined.
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