Protecting solutions of parenteral nutrition from peroxidation

Background: Light exposure induces the generation of peroxides in solutions of total parenteral nutrition (TPN). Peroxide toxicity has been documented in cell, in tissue, and in isolated organs. To decrease the infused peroxi de load and to protect the quality of the parenteral nutrients, we tested t he photoprotective properties of different infusion sets. Methods: Solution s of fat-free TPN and all-in-one total nutrient admixture (TNA) were run th rough sets of bags (clear and covered) and tubings (clear and colored: blac k, orange, and yellow) offering different levels of protection against ligh t. Peroxide levels were determined by ferrous oxidation of xylenol orange, thiol functions by the 5,5,-dithiobis(2-nitrobenzoic acid) technique, and a bsorbance of tubings by spectroscopy. Results: Protection of only the bag h ad little effect on peroxide generation. In fat-free TPN solutions kept in covered bags, peroxide concentrations were 1.5 to 2 times higher when run t hrough clear compared with colored tubings. When exposed to phototherapy or in the presence of lipids, peroxides were two to three times higher with t he clear compared with the black tubing; meanwhile, orange and yellow tubin gs offered varying levels of protection related to their light-absorbing pr operties. Colored tubings offered a greater protection against the disappea rance of thiol functions. Conclusions: Covering bags and using orange and y ellow tubings may be a practical solution to reduce infused peroxide loads from about 400 to 100 mu M. This is especially relevant in patients with an immature or a compromised antioxidant capacity or when phototherapy or pre parations of TNA are used.