Non-flushing of IV administration sets: an under-recognised under-dosing risk

intravenous (IV) drugs are administered widely and under-dosing can result in therapy failure. The aim of this study was to quantify frequency, volume and dose of drug discarded within administration sets in the clinical setting.

residual volume for 24 different administration sets was measured under controlled conditions in a laboratory. Clinical assessment of current practice regarding post-infusion flushing occurred in 6 departments of one teaching hospital in the UK over 7 days. Details of drug last infused, (concentration, diluent and volume) and type and brand of administration set were collected.

74% of administration sets were not flushed. Non-flushing exceeded 90% and 61% for gravity and pump infusions respectively (p<0.001) in all areas excluding oncology. Oncology was the only area where flushing was standard practice for all infusions (p<0.001). Mean residual volume of the administration sets was 13.1 ml and 16.7 ml for gravity and pump sets respectively. Antibiotics were commonly infused and up to 21% of antibiotic dose was frequently discarded.

the findings suggest disposal of substantial volumes of drugs occurs frequently in general hospital areas. Without clear national and local policies this unrecognised under-dosing will continue.