The hospital performs service and repair by themselves.No repair was requested.No parts have reportedly been replaced.The investigation consists of an evaluation of the information from the hospital and the provided ventilator logs.The device log evaluation confirms several alarms have been generated as an indication of difficulties with ventilating the patient.The event log shows that the ventilator was set to prvc (pressure regulated volume control) mode but was changed several times to and from simv (press.Contr.)+ pressure support mode.Alarms for high airway pressure, regulation pressure limited and expiratory minute volume low were generated to and from during the ventilation period.Those alarms indicate that the ventilator was functioning and it attempted to deliver the set tidal volumes but it failed due to the imposed restriction of the set upper pressure limit.In prvc mode the ventilator delivers a pre-set tidal volume and the pressure is automatically regulated to deliver the pre-set volume but it is limited to 5 cm h2o below the set upper pressure limit.The regulation pressure limited alarm is generated when the set volume is not attained due to the imposed restriction of the set upper pressure limit (-5 cm h2o).The high airway pressure alarm is generated when the upper pressure limit is reached whereby the inspiration phase is terminated and goes over to expiration.It is noted in the logs that when the alarm for regulation pressure limited was generated the user has tried to compensate by increasing the set tidal volume, but this does not work due to the restriction of the set upper pressure limit.Other alarms such as inspiratory flow overrange, inspiratory tidal volume overrange, peep low were also generated.These alarms indicate a leakage in the patient breathing circuit.During the situation causing the alarms, the measured volume will be different than the set or expected volume.Generated alarms were silenced by the user indicating that the ventilator was under surveillance.The technical log does not contain any technical error codes to indicate that there was a ventilator malfunction at the time of the event.The ventilator passed pre-use check prior ventilation was started.However, during the patient circuit test the compressible volume was measured to 0.22 ml/cm h2o, which is an indication that the test was not performed with the patient circuits but with the test tube.However, the deviation from correct compliance value does not contribute to this issue.There is no indication of a ventilator malfunction at the time of the event.The exact time of the event during the ventilation period was not stated.During the first 30 minutes and the last 30 minutes of the ventilation, several alarms were generated indication a large leakage.In between these periods, alarms were generated indicating a higher pressure than intended to the patient.The cause of the reported difficulties with ventilating the patient was most likely not suitable parameter or alarm limit settings for the patient and/or a leakage in the patient breathing circuit.Leakage may have gone un-detected since the used patient circuit was not tested during pre-use check prior ventilation was started.The cause of the leakage has not been determined.
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