The Interlink Vial Access Cannula consists of a blunt plastic cannula with a removable spike inserted into the lumen of the cannula. The blue plastic spike allows for needleless access of a single-dose vial. When the cannula is removed from the vial, the spike remains embedded in the stopper, and the blunt plastic cannula can then be used to access InterLink injection sites.
Becton Dickinson initially became aware of instances of fracturing of the end of the blue spike of the Interlink Vial Access Cannula in August 2003, in which small solitary fragments of the spike were found in syringe barrels. Our investigation revealed the root cause of the fracturing was related to the product assembly process. To reduce the potential for broken spikes, immediate action was taken to correct the manufacturing process. Modification of the process was completed in August 2003, and since the change was made, 413,188 samples have been inspected during manufacturing, and no broken spikes have been detected. In addition, a sampling and simulated-use evaluation of 5,000 units (1,000 units from each of five lots) of current inventory was undertaken in November 2004 to further confirm the effectiveness of the corrective action. No fractures or fragments were observed during this testing, in which the product is used to penetrate and draw fluid from medication vials in a laboratory setting.
When the issue was first reported in 2003, to assess the potential risk of product manufactured before correction of the problem, Becton Dickinson evaluated more than 14,000 units through simulated use testing. Only one broken spike was found, and the single resulting fragment was drawn into the syringe barrel during the simulation, in much the same way that the fragment reported by Drs. Kohli and Florence was drawn into the syringe. However, the piece was elongated and could not be readily flushed through the lumen of the Interlink Vial Access Cannula, which has a diameter equivalent to that of a 15-gauge intravenous catheter (0.054 inches or 1.37 mm in diameter). (In order for an irregularly shaped fragment that exceeds the diameter of the cannula in any dimension to be flushed through the cannula, it would need to be oriented as it enters the cannula so as to allow its narrower profile to clear the walls of the cannula lumen.)
Intravenous catheters normally have a lumen gauge that is higher than 15 and is therefore smaller than that of the cannula. In the event that a small piece was flushed through the Interlink plastic cannula, it would most likely be prevented from entering the circulation by the yet narrower catheter lumen. In the unlikely situation that a fragment detaches that is small enough to be flushed through both the cannula and catheter (the ID of a 20-gauge peripheral intravenous catheter is 0.030 inches, whereas the ID of a 24-gauge peripheral intravenous catheter is 0.019 inches), given the inert nature of the polycarbonate spike material and the small size of the particle released, there is minimal risk of such an embolized particle causing harm to a patient. Consistent with this assessment is the lack of patient injury reports received by Becton Dickinson during the 24 months preceding the August 2003 reports.
Becton Dickinson believes we have addressed the problem reported here by Drs. Kohli and Florence but is continuing to monitor the product to ensure that the problem does not reoccur. Becton Dickinson appreciates the information provided to us by clinicians regarding the performance of our devices. We take very seriously any complaints or issues related to our products, and we are committed to resolving such issues as rapidly as possible.
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