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Visual inspection found no anomalies in the appearance.The actual device, after having been rinsed and dried was tested for its gas transfer performance in accordance with the factory's shipping inspection protocol.Bovine blood arranged to hb12.0 g/dl, temp.37oc., ph:7.4, svo2:65% and pvco2:45mmhg was circulated in the oxygenator module under the following conditions: @ v/q=1, fio2=100% and the flaw rate of 5l/min.And 3l/min.Result: o2 transfer: @5l/min.= 321ml/min.@3l/min.= 209ml/min.Co2 removal: @5l/min.= 262ml/min.@3l/min.= 180ml/min.No anomalies were revealed in the gas transfer performance of the actual device with the obtained values meeting the manufacturing specifications.Review of the pump record from the involved procedure found the blood gas not only dropped pao2 but also increased paco2 implying there may have been some factor(s) which prevented the gases from being transferred sufficiently.A review of the device history record and product release decision control sheet of the involved product code/lot number combination revealed no relevant findings.A search of the complaint file found no previous report of this nature with the involved product code/lot number combination.There is no evidence this event was related to a device defect or malfunction.The investigation result verified the actual device, after having been rinsed, was the normal product with no issue in the gas transfer performance.While the exact cause of the reported event cannot be definitively determined based on the available information, it is likely some factor(s) prevented the gas transfer of the actual device from being performed sufficiently.(1) clots formed inside the oxygenator module may prevent the gases from being transferred sufficiently.(2) water drops generated due to the occurrence of the wet lung phenomenon may prevent the gases from being transferred sufficiently.(3) there may have a leak on the gas line preventing the gases from flowing through the oxygenator module.The device labeling does address the potential for such an event in the instructions-for-use (ifu) with statements such as the following: measure blood gases and make necessary adjustments as follows.Control pao2 by changing concentration of oxygen in ventilating gas using gas blender.To decrease pao2, decrease fio2.To increase pao2, increase fio2.Control paco2 by changing the total gas flow.To decrease paco2, increase total gas flow.To increase paco2, decrease total gas flow.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 15l/min for 10 seconds.Do not repeat this flushing technique, even if oxygenator performance is not improved.All available information has been placed on file in quality assurance at the manufacturing facility for appropriate tracking, trending and follow-up.
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