Use of two needles
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Editor, – Since my intern days, I have always used one needle to draw up a medication into a syringe (except for plastic ampoules, where I fit the syringe nozzle directly), then replaced this needle with a second one for the actual injection. Since talking to doctors who use the one needle for both purposes, I am unable to confidently justify my 'wastage'. Is there a risk of a glass fragment (or rubber, in the case of the rubber-sealed ampoules) attaching itself to the needle tip?
Sumner Park, Qld
Dr Paul Nisselle, the Australasian Secretary of the Medical Protection Society, comments:
The Medical Protection Society does not have any cases in its international database of a patient asserting damage resulting from using one needle to both aspirate medication from an ampoule and inject the medication into the patient.
The rationale, as I understand it, for using two needles when aspirating from a rubber-sealed ampoule is:
- the needle will be significantly blunted having perforated the rubber seal, and hence the subsequent injection will be more traumatic to the patient than when a fresh, perfectly sharp needle is used
- the outside of the needle may be contaminated going through the rubber, and that contamination could then be transferred to the patient if the same needle is used
- most rubber-sealed ampoules were used for multi-dose administration, and hence it was thought that changing to a second needle reduced the possibility of patient-to-patient transmission of contamination or infection.
Generally speaking, multi-dose ampoules have been abandoned, and hence the latter point does not arise.
With a glass-topped ampoule, I see no particular reason for using one needle to draw up the medication and another to inject it. If there are any single-dose, rubber-topped ampoules, then continuation of using two needles may well be appropriate in that circumstance, as there will still be the blunt needle problem.
However, to repeat, I know of no instance where a patient has come to harm and sought compensation as a result of using only one needle to aspirate and then inject medication from a single-dose ampoule.