Udi: not required for product code.Implanted date: device was not implanted.Explanted date: device was not explanted.Occupation: clinical engineer.Pma/510(k): k130280.The actual sample was received for evaluation.Visual inspection revealed no break or no other anomaly in the appearance.Air was blown from the gas inlet of the actual sample.As a result, liquid was observed adhering to the housing on the gas outflow side; however, as it was a very small amount, it was not possible to identify the liquid.The actual sample, after having been rinsed and dried, was tested for its oxygenation and co2 removal performance in accordance with the factory's inspection protocol.No anomaly was observed, and the obtained values met the control criteria.Bovine blood conditions: hb:12g/dl, temp.: 37°c., ph:7.4, svo2:65%, pvco2: 45mmhg.Circulation conditions: blood flow rate: 2l/min and 1l/min, v/q=1, fio2=100%.O2 transfer volume: @2l/min= 124 ml/min.@1l/min= 70 ml/min.Co2 removal volume: @2l/min= 82 ml/min.@1l/min= 53 ml/min.A review of the device history record and product-release judgement record of the involved product code/lot# combination was conducted with no findings.The pump record review revealed: the blood flow rate was found to be constant at about 0.9-1.0 l/min.In addition, the arterial and venous pressures were found following the changes in blood flow rate and not change drastically.Therefore, it was unlikely that blood clot formation was a factor.When pao2 decreased, fio2 and gas flow rate were increased.Pao2 increased temporarily, and then decreased gradually.Therefore, it was likely that the gas exchange performance decreased for some reason.It could not be clarified if the degradation in gas transfer performance was relevant to the event noted in the pump record (start of rewarming, ao declamp) or the administration of heparin/ffp.The pao2 was found markedly fluctuating from around 16:00 (at the beginning of the provided pump record).The blood gas data after 16:00 showed a gradual decrease in svo2, suggesting that this may have contributed to the decrease in pao2.Ifu states: a phenomenon called wet lung may occur when water condensation occurs inside fibers of microporous membrane oxygenators with blood flowing exterior to the fibers.This may occur when oxygenators are used for a longer period of time.If water condensation and/or a decrease in pao2 and/or an increase in paco2 is noted during extended oxygenator use, briefly increasing the gas flow rate may improve the performance.Increase gas flow rate, to 5 l/min for 10 seconds.Do not repeat this flushing technique, even if oxygenator performance is not improved.Measure blood gases and make necessary adjustments as follows.A.Control pao2 by changing concentration of oxygen in ventilating gas using gas blender.To decrease pao2, decrease fio2.To increase pao2, increase fio2.Based on the provided information and investigation results, there is no definitive evidence that this event was related to a device defect or malfunction.The investigation results verified the returned sample was of normal product.It is likely that from the liquid flowed out from the gas channel, it was presumed that hydrophilization of the fiber occurred disrupting the balance maintained in the micropores of the fiber between the blood surface tension and the gas pressure, resulting in plasma leak and decrease in the gas exchange performance.The decrease in the gas exchange performance of the actual sample caused a decrease in the oxygen supply to the patient, resulting in the decrease in svo2 and pao2.However, the exact cause of the reported event cannot be definitively determined based on the available information.(b)(4).
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The user facility reported that four hours after the start of circulation, oxygenation performance dropped sharply.Increasing gas flaw up to 10l/min could not improve the situation.Gas flushing was repeated three times, although that could not either.Replacement of the oxygenator was discussed; however, since it was already at the end of the case, it was judged that there would be no problem, and the oxygenator in question was continued to be used as it was.The procedure was finished safely and was completed successfully.The patient was not harmed.
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