Patient identifier - requested, not provided.Age & date of birth - requested, not provided.Sex - requested, not provided.Weight - requested, not provided.Ethnicity - requested, not provided.Race - requested, not provided.Udi: not required for product code.Implanted date: device was not implanted.Explanted date: device was not explanted.The actual device was returned for evaluation.Visual inspection upon receipt revealed no anomalies, such as a break, which was visible to unaided eye, in the appearance.The actual sample was rinsed by letting saline solution to flow through it by gravity.Subsequently, saline solution was circulated in the blood phase at each flow rate, while the pressure drop was determined.The obtained values in the pressure drop were found to be higher than normal.The actual sample was rinsed and was built into a circuit with tubes.Bovine blood was circulated in it with a roller pump.The normal flow of blood going forward the blood outlet was confirmed.During the circulation, it was noted that blood leaked out of some of the fibers into the filtrate phase and started to pool there.Magnifying inspection of the leak found some of the fibers had been cut.A review of the device history record and product release decision control sheet of the involved product code/lot number combination was conducted with no findings.There is no evidence that this event was related to a device defect or malfunction.The exact cause of the reported event cannot be definitively determined based on the available information.During the above investigation, the pressure drop of the actual sample was found to be higher than that of the current product sample.This indicated that the actual sample had been clogged.During the above circulation test, blood was confirmed to come out of the blood outlet.From this it is assumable that the actual sample had been clogged with clots generated inside the fibers.However, it is difficult to determine the cause of clot formation.Regarding to the leak found on the actual sample upon received by the factory for evaluation, as a possible cause, it is likely when the actual sample was subjected to shock force in the state of dried blood adhering to the fibers, stress was concentrated to the blood adhering segment, resulting in the break in the fibers.From the state of the actual sample upon receipt after it having been subjected to the cleansing process, it is difficult to determine when and how the fibers became broken.(b)(4).
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