INTEGRITY OF ONE-WAY BACKFLOW VALVES ALLOWING FOR MULTI-PATIENT USE OF LOW OSMOLAR INTRAVENOUS CONTRAST SOLUTION (LOICS),

M. Garcia, RN, CIC*, S. Woodward, RT, K. Anderson, A. Easty, PhD, D. Gretzinger, BEng, J. Cafazzo, MHSc, J. Ratner, PhD, H. Dedier, J. Yao, MD, J. Conly, MD,

The Toronto Hospital, Toronto, Ontario, Canada.

Background: Low osmolar intravenous contrast solution (LOICS) are widely used in hospitals for diagnostic radiological studies. At our hospital a 1200 bed tertiary care hospital over 15000 diagnostic procedures are performed each year. Due to the high cost of LOICS, single bags of the solution have been proposed for use in multiple patients in diagnostic radiology. Little data exits on the potential contamination of these multi-use infusion bags by blood/body fluids using a one-way check valve. We therefore designed a study to assess the integrity of a one-way valve as a functional and structural barrier to blood/body fluids in this setting.
Objectives: To assess the integrity of one-way check valves in the prevention of backflow of potentially contaminated solution into multiple-use intravenous contrast solution.
Methods: Structural testing of the valves was assessed using a short (15 seconds) and long-term (60 min.) static back pressure test at 60 psi and a clinical simulation test using a syringe pump. Time pressure profiles were recorded using Biotek DPM III gauges. Functional testing of the valves was done using methylene blue and 99m-technetium pertechnate (99mTc) as a surrogate tracer molecule and bacteriophage PHL55 as a small viral surrogate. Multiple aliquots were obtained via a 3-way stopcock just distal to the valve after each of 3 consecutive 1 minute pressure challenges of 300 mm Hg (5.8 psi) along with appropriate positive controls. Aliquots were transferred to clean tubes for counting or a propagating broth culture of Staphylococcus aureus as appropriate.
Results: Of 10 sprung type one-way valves tested from separate lot numbers, no radioactivity and no viable phage could be detected in any of 40 samples from the pressure challenge experiments. Structural testing indicated integrity for all pressures tested <15 psi.
Conclusions: The results of these experiments suggest that one-way check valves of the sprung type can provide an integral barrier to backflow and allows the use of a single bag of LOICS at significant cost savings.

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