A rubber stopper is a small, tapered plug used to seal the openings of test tubes, flasks and other laboratory glassware. Stoppers made of cork are also available for this purpose. However, rubber stoppers are preferable for applications that require a tighter seal or a greater degree of chemical resistance.
Rubber stoppers allow easy access to drugs contained in glass medication vials, as they can be readily punctured through with a needle or a cannula.
After a needle is inserted through the stopper of a medication vial, a small piece of the stopper is sometimes sheared off (known as coring) and may not be noticed.
This small foreign body can then be aspirated into a syringe and injected into a patient. For many years, the contamination of parenteral fluids and medications by particulate matter has been recognized as a potential health hazard
There are strategies that both we and the manufacturers can employ to help reduce or eliminate the risk of coring. If the needle must pierce a stopper, there is a needle insertion technique that reduces the risk of coring during needle insertion through the stopper of a medication vial. The needle should be inserted at a 45-60° angle to the plane of the stopper with the opening of the needle tip facing up (i.e., away from the stopper). A small amount of pressure is applied and the angle is gradually increased as the needle enters the vial. The needle should be at a 90° angle just as the needle bevel passes through the stopper. Second, if the stoppers were made of a material that always floated and were of a noticeable color, they would be easier to spot and would be less likely to be injected in a vertically-oriented syringe.
We hope this communication will bring to the attention of the readership a probably infrequent but potentially serious problem that is not well known in the anesthesia community. We hope this letter prompts us to consider an engineering solution, of which several suggestions were presented above. In the meantime, we should utilize the technique described above when piercing a stopper with a needle, which adds no financial cost and takes at most an additional 1 or 2 seconds.
