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Submit date: 08/21/2017.An investigation is currently underway.Upon completion, the results will be forwarded.A good faith effort will be made to obtain the applicable information relevant to the report.If information is provided in the future, a supplemental report will be issued.
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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.Complaint samples were received in the form of twenty (20) defib electrodes.Ten (10) were received in opened pouches or not in a pouch at all and the other ten (10) were in unopened pouches.The pouches indicated production lot number 605025x.The degree of delamination on the on electrode pads were evaluated on the samples per the manual single directional peel test in the quality lab.The degree of gel separation/delamination was determined to be within the defined acceptance criteria.Upon visual inspection of the electrodes not contained within sealed pouches gel delamination from the substrate was observed on three (3) of the ten (10) electrode.On one set only one pad could be evaluated as the one of the pads within a set was folded over itself (received in this condition from customer) and could not be pulled apart without destroying it.It was assumed that delamination was present, however the degree could not be evaluated.The other pad within this set had a small amount of delamination in the center of the electrode, it extended into the conductive mat, however the delamination was under the 22% maximum (1%).Of the delamination observed on the three (3) sets the maximum delamination observed was 6.1%.Of the ten (10) sealed pouches none of the electrode sets exhibited delamination.Five (5) out of the ten (10) sealed electrodes did exhibited some gel roll.Gel roll is a condition whereby the gel becomes rippled, but does not separate from the silver printed substrate.As the gel did not fully separate it is not considered delamination.As previously stated, all of the gel delamination observed within 45% maximum hydrogel separation from the adult electrode acceptance criteria and under the 22% maximum when conductive mat was included.The production retains for the finished goods, as well as the gel body sub-assemblies were also evaluated for delamination.No delamination was observed.The results of the testing, pictures of returned samples showing the condition of the electrodes and the delamination observed are attached.Maximum delamination observed was 12.3%.On one of the electrodes the delamination extended into the conductive mat, however the delamination was under the 22% maximum.Of the other eighty-three (83) electrode sets twenty (20) random pouches were opened and evaluated.Sampling was based on a c=0 sampling plan at an aql of 0.65.The degree of delamination on the on electrode pads were evaluated on the samples per the manual single directional peel test in the quality lab.The degree of gel separation/delamination was determined to be within the defined acceptance criteria.Four (4) instances of delamination was observed.The maximum percentage was 12.5% (included conductive mat).Gel roll was observed on six electrode sets.Gel roll is a condition whereby the gel becomes rippled, but does not separate from the silver printed substrate.As the gel did not fully separate it is not considered delamination.As previously stated, all of the gel delamination observed within 45% maximum hydrogel separation from the adult electrode acceptance criteria and under the 22% maximum when conductive mat was included.The electrodes (5 sets) were also evaluated for electrical functional properties.The electrodes meet the acceptance criteria.The production retains for the finished goods, as well as the gel body sub-assemblies were also evaluated for delamination and yellow discoloration.No delamination or severe yellowing discoloration was observed.The results of the testing, pictures of returned samples showing the condition of the electrodes and the delamination observed are attached.Based on the complaint description provided by this complaint is confirmed as gel delamination, however it could not be determined if it was specifically related to manufacturing process.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.Another potential root cause related to manufacturing is that the silver ink re-mixing was not adequately performed during the sub-assembly printing process.If the silver ink is not adequately it may not properly dry which could result in gel not properly adhering to the silver printed substrate.This may contribute to gel delamination.Silver mixtures can become separated over time because they are suspensions; this is visually detectable prior to use.If re-mixing is required the machine operator documents this process occurred and that the silver mixture met the required acceptance criteria.A review of the production records indicated that silver re-mixing was not required.Additionally, gel delamination may become exacerbated if the defib electrodes are not improper storage, and can become more prevalent as the product approaches the expiration date.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 exhibited delamination.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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