Peripheral venous nutrition: the equal relevance of volume load and osmolarity in relation to phlebitis

This study aimed to investigate the peripheral vein tolerance for total parenteral nutrition (TPN) and to point out the factors which induce phlebitis. TPN was administered from 'all-in-one' bags. Five different types of TPN were investigated, wherein the amounts of amino-acids, dextrose, lipids, osmolarity and volume were varied. Type I (829 mOsm/l) was a low energy (1570 NPE kcal) nutritive mixture of 2425 ml with 9.5 g N. Type II (842 mOsm/l) was an intermediate energy (1800 NPE kcal) mixture of 2525 ml with 9.5 g N. Type III (860 mOsm/l) contained 1800 NPE kcal and 13.5 g N in 2775 ml. Type IV (790 mOsm/l) was only a dilution of Type III with 250 ml water. Type V (1044 mOsm/l) covered normal energy needs (2000 NPE kcal) and 13.5 g N in 2580 ml. All bags contained standard amounts of electrolytes, vitamines, trace elements and heparin (1.000 IE/l). The infusion site was not changed until phlebitis developed or oral feeding could be started. Type I, II, III and IV were given to at least 30 patients, and Type V to only 11 patients because of an unacceptable high phlebitis rate (91% after 2.8 days). The phlebitis rate for Type I, II, III and IV was 4%, 12%, 24% and 27% respectively after 48h increasing to 14%, 37%, 55% and 73% respectively after 14 days. The mean infusion time and phlebitis rate were related to each component of the nutritive mixture. A poor relation was found between the phlebitis rate and the amount of amino-acids, dextrose or lipid respectively. Both osmolarity (with variabl volume) and volume (with variable osmolarity) correlated poorly with the phlebitis rate (r = 0.37 and 0.29 respectively). However, the osmolarity rate, defined as the number of milliOsmols infused per hour, correlated well with the phlebitis rate (r = 0.95). Our results demonstrate that the peripheral route can be used as a practical alternative for central venous administration, if the osmolarity rate is limited.