Can the use of 70% isopropyl alcohol swab or aspiration using 5 microm Filter Straw reduce bacterial contamination of fentanyl solution used for regional anaesthesia?

This prospective study aimed to determine the extent of contamination of fentanyl solutions used for central neuraxial injection by wiping the neck of the ampoules with 70% isopropyl alcohol swabs (Kendall) before breaking open the ampoules and aspiration of fentanyl solutions using a 5 microm Filter Straw (B. Braun). In Group A, fifty fentanyl ampoules were wiped with 70% isopropyl alcohol swab prior to opening and the contents were aspirated immediately using a 21G needle and a 5 microm filter straw for culture. The same steps were repeated on the remaining solutions after two hours. In Group B, all the above steps were repeated but without wiping the ampoules with 70% isopropyl alcohol swabs. None of the samples from the wiped ampoules or aspiration using filter straw grew microorganisms. Six percent of the samples from unwiped group grew microorganisms when fentanyl were aspirated using a 21G needle and the contamination increased to 16% when repeated after two hours. Wiping the outsides of the fentanyl ampoules with 70% isopropyl alcohol swabs before opening or aspirating the contents using a 5 pm filter straw has been shown to be equally effective in avoiding bacterial contamination and should be practiced routinely when performing regional anaesthesia.