Intraoperative Fire Risk: Evaluating the 3-Minute Wait After Chlorhexidine-Alcohol Antiseptic Scrub

We sought to determine the flammability of the skin at different time intervals after chlorhexidine-alcohol antiseptic scrub application, to provide evidence for hospital protocols recommending a 3-minute drying time.

Swine feet, which contain the skin, subcutaneous tissue, muscle, and bone, were used for an experimental cohort. The skin was prepped with chlorhexidine-alcohol solution. Attempted ignition with an open flame was then performed in the presence of visible pooling, as well as at time points 0, 30, 60, and 90 seconds after application, in addition to when the skin appeared visibly dry. Six samples were used for each time point tested.

At time 0 seconds and with gross pooling, ignition was achieved with all samples tested. However, at 30 seconds, only 2 of 6 samples were ignited (which appeared wet). No samples after 60 or 90 seconds were flammable. Samples appeared dry after an average of 40.5 seconds and were not able to ignite.

Although our findings do support that a chlorhexidine-alcohol antiseptic scrub is a potentially flammable surgical prep solution, we found little support for a 3-minute time cutoff. More importantly, the presence of pooling and persistently wet appearing prep is a more important fire risk than the time elapsed after prep application. Caution should be used when working with any flammable solution, and efforts to minimize chemical burns and combustion should be sought based on evidence.