BIOSAFETY ANALYSIS OF ONE-WAY BACKFLOW VALVES FOR MULTIPLE PATIENT USE FOR LOW OSMOLAR INTRAVENOUS CONTRAST SOLUTION (LOICS).

M Garcia*, S Woodward, K Anderson, A Easty, H Dedier, J Yao, J Conly,

Depts. Of Microbiology, Nuclear Medicine, and Medical Engineering, The Toronto Hospital, University of Toronto, Toronto, Ontario

Background: Due to the large volumes and high cost of LOICS, single bags of the solutions have been proposed for use in multiple patients in diagnostic radiology. However, there is little data on the potential contaminations of these multi-use bags by blood/body fluids during such procedures eve with the use of 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 on-way check valves in the prevention of backflow of potentially contaminated solution into sterile multi-use LOICS.

Methods: Functional testing of the valve integrity was done using methylene blue and 99m-technetium pertechnate(99mTc) as a surrogate tracer molecule at a concentration of 40 mBq/L of sterile saline. Multiple aliquots of 5 ml 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(5.80 psi_ along with appropriate positive controls. In addition, aliquots were obtained in a similar manner at 10' intervals in a separate time-exposure experiment. Aliquots were transferred to clean tubes for counting. Structural testing of the valves was done using a series of graded pressures from 0 to 10 psi.

Results: Of 10 Medex, Inc. One-way valves tested from separate lot numbers, radioactivity could be detected in 0/40 samples from the pressure challenge experiments and 0/21 samples from the time-exposure experiments. Structural testing of all lots indicated integrity for all pressures tested.

Conclusion: The results of these experiments suggest that on-way check valves can provide an integral barrier to backflow and allows the use of a single bag of LOICS at significant cost savings.