A Review of intravenous (IV) delivery systems for enhanced computerized tomography (CT) sprung from personal observation

ISSUE: An infection control practitioner who underwent enhanced CT scanning noticed multiple patient infusions of contrast dye from a single infusion syringe. High costs and large volumes of the dye drive this practice. A review was conducted to determine current practices and assess patient risk. PROJECT: Advisories and alerts related to enhanced CT delivery systems were researched, and the enhanced CT practices at two local hospitals were evaluated. For this review, the “extension tubing” is the delivery system between the dye container and the patient IV connection. A “sprung” type backflow valve is any valve for which significant pressure (3.4 psi) is required to open the valve. An “unsprung” valve is any valve that can be opened with less pressure, indicating that it is less effective in protecting against backflow. RESULTS: A 1995 Health Canada Advisory recommends placement of two “sprung” type, backflow valves in the extension tubing to substantially reduce (but not necessarily to eliminate) the risk of contamination. Review of two local hospitals revealed that both used two “sprung” valves in the extension tubing as recommended; the extension tubing with valves are single use only. However, differences were found in the set-up for flushing the patient IV which may allow for contamination. In one hospital, the set-up was pre-primed for all patients at the beginning of the day. In the other hospital, the set-up involved a single normal saline bag with IV tubing repeatedly used throughout the day and additional IV tubing with an “unsprung” valve, single use only. The value of protection from backflow of blood and bloodborne pathogens by the single “unsprung” valves has not been described. LESSONS LEARNED: Differences in contrast dye IV delivery systems exist between hospitals. Both hospitals reviewed used two “sprung” type, backflow valves in their extension tubing, but methods of flushing lines between procedures were inconsistent. Further studies are needed to document the risks of contamination with the use of “sprung” and “unsprung” backflow valves for multidosing of contrast dye. National standards are needed to ensure consistency of practice between hospitals.