The customer reports the gel came off the backing.This type of event is commonly referred to gel delamination.Gel delamination occurs when the gel-to-release liner bond strength is greater than the cohesive strength of the gel or greater than the gel-to-substrate bond strength.Such an inequity in bond strength can cause the gel to peel from the substrate and/or tear.Delamination is categorized as follows: an aesthetic delamination defect is characterized by a permanent separation of the hydrogel from the substrate, exposing the underlying carbon vinyl with little (i.E.Area less than 1/8 inch x 1/8 inch) or no hydrogel remains on the release liner.Also, no silver/silver chloride ink is exposed.Aesthetic delamination defects will not significantly affect electrode function, but may displease the clinician.Functional delamination is a permanent separation of the hydrogel from the substrate such that the silver/silver chloride ink remains exposed.Additionally, per the defibrillation electrodes design input document for defibrillation electrodes, when the release liner is removed from the electrode, there shall be no more than no more than 45% hydrogel separation from the adult electrode.When the area of separation includes the area of underlying conductive mat, the maximum amount of hydrogel lost is 22% for adult electrodes.With loss of the hydrogel less than the percentages as defined above the electrodes retain functionally essential performance; however the reduction in the hydrogel area with the silver/silver chloride ink being exposed may cause an increase in current density across the remaining gel area.This increases the potential for skin irritation and burns.The device history record (dhr) for the hydrogel body sub-assembly met all acceptance criteria.The uv dosage outputs for curing the hydrogel bodies were within the proper range.The conductive silver/silver chloride ink and gel batch mix sheets were also reviewed.All components and mix time were within tolerance.During the production of hydrogel bodies, four corner peel testing is performed to simulate the removal of the electrode release liner by a clinician prior to delivering therapy (corners of gel body are lifted from the liner to evaluate for release of gel from the substrate).The production lot numbers for the hydrogel body sub-assembly, 602903, did exhibit some minor aesthetic delamination and had no functional delamination.A complaint sample was received in the form of 1 defib electrode set.The electrode was received in the original pouch.The pouch was unopened.The pouch indicated production lot number 605025x.The pouch was opened and the electrode was evaluated in the lab.Upon visual inspection of the electrodes gel pads delamination was not observed.The carrier liner was removed from each electrode pad and the gel remained intact.Production retains (5 sets) for lot # 605025x were evaluated as well.None of the five (5) retains evaluated exhibited delamination.Based on the complaint description provided by this complaint is confirmed as gel delamination, however it could not be determined if it was related to manufacturing process.The severity of the gel delamination observed by the customer could not be evaluated as samples exhibiting delamination were not provided and production retains did not exhibit any delamination.In terms of a potential root causes, either the gel was insufficiently cured (the strength of the bond between the gel and the substrate was too weak) or there was insufficient silicone on the mylar liner (the strength of the bond between the gel and the plastic liner was too strong), however none of the production records or incoming inspection records indicate this occurred.Gel delamination may become exacerbated the defib electrodes are not improper storage.As indicated on the product packaging proper storage and usage of the electrodes is critical to the performance of the gel.The electrodes should be stored in their sealed protective pouch in a cool, dry place and out of direct sunlight.Do not open package until ready for use.Do not bend, fold, or puncture the packaging.Improper storage conditions and/or handling of the product may compromise gel properties prior to the expiration.The environmental and handling condition in which the product was stored was not provided with the complaint.Based upon the investigative details and the root cause evaluation, no further corrective or preventative actions will be taken at this time in relation to the customer described event.We will continue to trend this defect for future occurrences as part of the complaint review process.If information is provided in the future, a supplemental report will be issued.
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