Chapman AK, Aucott SW, Gilmore MM, Advani S, Clarke W, Milstone AM: Absorption and tolerability of aqueous chlorhexidine gluconate used for skin antisepsis prior to catheter insertion in preterm neonates. J Perinatol 2013. This group from Hopkins measured chlorhexidine serum levels after it was used to clean the skin of 20 preterm babies for picc line insertion. They were able to detect chlorhexidine in 10 of them between 1,6 and 206 nanograms per ml. I don’t know if that is a dangerous level, but nobody else does either. The levels increased for 2 to 3 days after the procedure, suggesting ongoing absorption from residual chorhexidine on the skin. Should we therefore always try and wash the chlorhexidine off the skin with sterile water after the procedure? One of the advantages of chlorhexidine is that it has a residual antibacterial activity, so maybe that isn’t a good idea.
There are some moves to introduce into the NICU a practice that was found to be modestly effective in a PICU study (reduced from 6.6 to 5.1 infections per 1000 patient days, Link here), to routinely bathe our patients using a chlorhexidine impregnated washcloth. Seeing this new article, I think that would be a very bad idea, outside of a good large trial to prove efficacy in our population, and some very careful evaluation of safety. If a little area of chlorhexidine for a picc insertion increases levels, total body coverage with it will certainly put them up much higher.