From Miss V. L. Magnall, MRPharmS, and Mrs S. Fairclough, MRPharmS
SIR,-It is common practice in a paediatric hospital for small volumes of drugs to be administered as a continuous or intermittent infusion necessitating the use of a syringe driver.
A problem arose at Alder Hey hospital relating to a syringe of flucytosine supplied in a 10ml luer lock Becton Dickinson syringe to be infused via a Graseby 3200 syringe driver. Nursing staff made a complaint to the pharmacy when at the end of the infusion there was still a residual volume of 0.5ml in the syringe. The nurses said that they never had this problem when using non-luer lock syringes in the syringe driver. Senior nursing staff stated that this is a frequent problem but had not reported it to the pharmacy or risk management department. Their solution was either to transfer the contents of the syringe supplied by pharmacy into a non-luer lock syringe, risking microbial contamination, or to infuse the majority of the dose and then bolus the remainder.
Samples of Becton Dickinson and Braun luer and non-luer lock syringes of various sizes from 5ml to 50ml were tested in both Graseby 3200 and Ivac P7000 syringe drivers. A difference in the plunger lengths was noted between the same brand of luer and non-luer lock syringes of volumes 3ml, 5ml and 10ml. All non-luer lock syringes infused the full contents of the syringe via the syringe drivers. The luer lock syringes were left with residual volumes of between 0.2ml and 0.6ml at the end of the infusion.
The Medical Devices Agency was contacted but has not followed this up as far as we are aware. This under-infusion may seem insignificant in adult practice but it could result in an underdose of up to 25 per cent in a neonate when very small volumes are infused.
We recommend that (i) pharmacists check the practice relating to the use of syringe drivers within their own trusts, (ii) manufacturers of syringe drivers and syringes work together to produce an effective product with clear guidelines on compatibility and (iii) the MDA provides further guidance and validation work.
Victoria Magnall
Principal Pharmacist
Sandra Fairclough
Deputy Chief Pharmacist, Alder Hey Children's Hospital, Liverpool