Nanocrystalline silver: a systematic review of randomized trials conducted on burned patients and an evidence-based assessment of potential advantages over older silver formulations.

The aim of this meta-analysis was to collect data from randomized trials in burn patients and to analyze them with a meta-analytic approach to give a clear message of potential advantages of nanocrystalline silver (NC) versus older silver formulations (SS). A review of all-English prospective randomized trials that compared NC versus silver sulfadiazine or silver nitrate was conducted. Primary outcome was the evaluation of differences in the infection rate of burns. Secondary outcomes were the eventual differences in the pain experienced during medications, the length of hospitalization (LOS) and costs. Five articles that met the inclusion criteria were selected (n = 285 patients). The NC group had a significant lower incidence of infections compared with the SS group (9.5% vs. 27.8%, odds ratio: 0.14 [95% CI: 0.06-0.35]; chi2 test, P < 0.001), with a 2.9-fold decrease of the risk. Not all studies investigated the pain during change of dressings, LOS and costs. However, when data were available, these showed lower costs (US $1533 per patient for the SS group and US $946 per patient for the NC group) and decreased pain values in the NC group (Hedges' G: -1.44 [95% CI: -1.86/-1.01]; P < 0.0001), while contrasting results were obtained for LOS. Nanocrystalline silver is a relatively new product with a significant stronger antimicrobial activity compared with older formulations. Its long lasting properties reduce dressing change frequency and are probably responsible for the decreased pain and the minor costs experienced.