RESUMO
BACKGROUND: Vitamin degradation occurring during the storage of total parenteral nutrition (TPN) mixtures is significant and affects clinical outcome. This study aimed to assess the influence of the TPN bag material, the temperature, and the duration of storage on the stability of different vitamins. METHODS: Solutions of multivitamin and trace elements at recommended doses were injected into either an ethylvinyl acetate (EVA) bag or a multilayered (ML) bag filled with 2500 mL of an identical mixture of carbohydrates (1200 kcal), fat (950 kcal), and amino acids (380 kcal). The bags were then stored at 4 degrees C, 21 degrees C, or 40 degrees C. Concentrations of vitamins A, B1, C, and E were measured up to 72 hours after compounding, using high-pressure liquid chromatography. RESULTS: Ten percent to 30% of vitamin C degradation occurred within the first minutes after TPN compounding. Vitamin C was more stable in ML bags (half-life: 68.6 hours at 4 degrees C, 24.4 hours at 21 degrees C, and 6.8 hours at 40 degrees C) than in EVA bags (half-life: 7.2 hours at 4 degrees C, 3.2 hours at 21 degrees C, and 1.1 hour at 40 degrees C). Moreover, appearance of dehydroascorbic acid in the TPN mixture did not compensate for vitamin C losses. Vitamin B1 was stable at 21 degrees C, but a 43% loss occurred at 40 degrees C after 72-hour storage in EVA bags. The other vitamins were stable in the TPN mixture stored in both bags at any temperature and without daylight protection. CONCLUSIONS: Degradations of vitamins C and B, are significantly reduced in ML bags compared with EVA bags. To prevent vitamin C deficiencies, its initial dose should be adapted to its degradation rate, which depends on the TPN bag material, the ambient temperature, and the length of time between TPN compounding and the end of infusion to the patient.
