Assessment of efficacy of post-infusion tubing rinsing in reducing cytotoxic contamination
1 : pharmacy department, Oncopole Toulouse France.
2 : risk management unit, Oncopole Toulouse France
Handling of cytotoxic is associated with occupational exposure of health care workers. Several guidelines have been published minimize this exposure. Since disconnection of infusion set is a source of contamination, rinsing tubing after infusion is recommended but the optimal volume of rinsing solution is unknown. The objective of this study was to assess the volume of rinsing solution leading to a total elimination of cytotoxic after infusion
Three drugs (cytarabine (2300 mg), gemcitabine (1900 mg) and paclitaxel (152 mg)) were diluted in 250 ml of NaCl 0.9% or Dextrose 5%. Infusions were performed using an infusion pump, through a VL ST00 infusion line (VL ON 70 for paclitaxel). After infusion the tubing was rinsed using a closed system transfer device (ICU medical, France)) without disconnecting infusion line. Total dead space volume of infusion sets were 26 ml for gemcitabine, cytarabine and 27 ml for paclitaxel.
Cytotoxic concentrations ([c]) were measured by a HPLC-UV method. A RP C18 column was used and mobile phase was an acetonitrile/0.1 % trifluoroacetic acid in water mixture at various proportion for each drug. Samples were collected just at the end of infusion and then after each 10 ml of rinsing until 100 ml.
Efficacy of rinsing was assessed by minimal [c] still detectable. The influence of rinsing condition was assessed by comparing the relative remaining concentration of cytotoxic at the half of rinsing according to rinsing solvent or rinsing flow rate (Wilcoxon test) or logP (Spearman correlation test).
Main results are shown in table. Max rinsing solution was 100 ml for Cytarabine and gemcitabine and 80 ml for paclitaxel.
No influence of rinsing solvent (p=0.849) nor flow rate (p=0.397) was found, while the remaining [c] was correlated with logP (r = 0.722; p<0.001).
Only paclitaxel was undetectable after rinsing, because LOD was high. After a rinsing volume of at least three times of dead space volume of infusion set, level of [c] of cytotoxic is still relevant, so even rinsed the tubing should be considered as a source of contamination. This study emphasizes the need of using closed transfer system device at the end of infusion line to minimize occupational exposure of health care workers. Optimal rinsing volume should be considered as the volume that allows a maximal administered dose with a minimal residual concentration but not a totally cleaned infusion line.