Study on the microbial safety of an infusion set for contrast-enhanced imaging

OBJECTIVES: Multiple uses of automatic contrast injection systems may impose septic risks on patients. The purpose of this experiment was to verify whether a newly developed replaceable patient-delivery system may allow multiple uses of the system but without such risks. METHODS: Twelve patient-delivery systems were tested according to a multiple-use approach using an automatic contrast injection system consisting of dual syringes and one filling and injecting set. Two protocols with normal saline only (n = 6) or contrast media plus normal saline (n = 6) loaded in the injection system were performed. Each patient-delivery system was connected through an infusion catheter to the ear vein of a rabbit that was intravenously preinjected with a diffusible radiotracer (99m)Tc-dimercaptopropionyl-human serum albumin. Aliquots were sampled from the filling and injecting set, patient line, and animal blood for radioactive analysis after the replacement of each patient-delivery system. RESULTS: For the protocol performed using only normal saline, radioactivity was found in the blood circulation of the rabbit (1655903 +/- 593221 CPM) and in the patient line (52894 +/- 33080 CPM), but, virtually, in none of samples from the filling and injecting set (8 +/- 3 CPM), relative to the background (7 +/- 3 CPM) (P = 0.726). Similarly, experimental results attained using contrast plus saline show radioactivity in the blood circulation of the rabbit (1119107 +/- 183174 CPM) as well as in the patient line (32991 +/- 20232 CPM) but in none of samples from the filling and injecting set (6 +/- 6 CPM), relative to the background (6 +/- 4 CPM) (P = 0.955). CONCLUSIONS: The tested patient-delivery system proves convenient and safe. It allows multiple uses of the contrast injection system and avoids the risk of cross contamination.