Background The closed system is designed, first, to protect patients and clinicians against exposure to hazardous drugs during the preparation of cytotoxic drugs and secondly, to protect the drugs against any exposure to external microbiological and physical contaminants.

Purpose The aim of this study was to determine the dead volume of spike–connector–syringe system used for the reconstitution of cytotoxic drugs and its impact on the variation of prepared doses.

Material and methods The spike, connector and syringe (10 or 20 mL) were weighed using an analytical balance before and after passing a solution of distilled water. Taking into account the density of water, we can thus determine the dead volume remaining in every material. For each measurement, the test was performed 30 times for each medical device.

Results The table shows that the dead volumes were different for the three devices: spike, connector and syringes (p<0.001). There was no significant differences between the dead volumes of the two syringes tested (10 and 20 mL) (p> 0.05).

Conclusion Reconstitution of cytotoxic drugs is influenced by several factors, some of which are controllable and others are unpredictable. The dead volumes can cause overdose or underdose, especially for preparations of low volume and expensive drugs. This phenomenon is important for connectors and spikes where the dead volume is about 0.2 mL and 0.1 mL, respectively. For syringes, the dead volume is not very important and does not vary with the volume of the syringe. This study showed that we must take into account the dead volume on reconstitution of cytotoxic drugs. Thus it would be highly advisable to use connectors whose dead volume is negligible compared with the prepared final volume.

References and/or acknowledgements Acknowledgements to the analytical chemistry team.

No conflict of interest