Iodine vs. Chlorhexidine skin prep

OK it isn’t the biggest or sexiest decision you might make on any day of the working week – but one where there is in fact some evidence.  Betadine  vs. Chlorhexidine – not really a hot debate.  Boring EM at best.

Are you making incisions in patients, or are you doing skin lac repairs?  I know that when I prep a surgical field I usually reach for the closest bottle of prep solution without giving it a moments thought.  But thanks to some ‘bottom-up’ education from local RMO, Dr Garg I have decided to be a Chlorhexidine in alcohol guy.

Why is this?  Well there are a few studies which he has pointed out to me which make a pretty convincing case for chlorhex over iodine – in terms of post-op wound infections it seems to be a winner.

Read them here:

Skin prep – NEJM 2010 (Chlorhex alcohol is better than povidone-iodine)

NYU skin prep review

2016 UPDATE: new RCT in NEJM Feb, 2016, looking at chlorhex vs iodine solutions for Cesarean post op infections….. Drumroll   – chlorhex wins by a nose

Now – a very astute reader (my wife) noted that the studies here are done with 2% chlorhex – however in Australia we tend to stock 0.5% Chlorhex in alcohol.  So let me know if you are aware of any data on the weaker solutions.  Are they still as good? Or can we translate these studies to Oz?

The aqueous vs. alcohol decision is easy in my shop as we don’t keep aqueous as standard on the trolley – however it seems that isopropyl alcohol solutions work fast – i.e. as they evaporate and dessicate the bugs over 1 – 2 minutes they have done their work.

Now – a few practical caveats to the idea that chlorhex in alcohol is all round great.

  1. You cannot use the strong isopropyl alcohol solutions directly onto mucosa (e.g. vaginal, mouth, or anywhere near the eyes)
  2. The alcohol-based solutions are flammable – but only if you don’t let them dry or let them pool in places e.g. umbilicus and then ignite them, with say, diathermy.  SO be aware of this – they need to dry to work properly anyway so – don’t leave it wet.
  3. Chlorhex in alcohol is neurotoxic…. in theory. (see this study from the Mayo in Amer Soc of Regional Anaesthesia).  It seems to be a rare event in spinal anaesthesia, but I think we should avoid it in areas where we are exposing nerves in ED – eg exploring deep lacerations.

My last learning point for you – I have been trying to teach this to my local RMOs for a while – if you have a contaminated wound and you want to flush out bits of the earth etc – then use large volumes of saline or other cheap and isotonic solution.  Using antiseptic solutions in this setting is just wrong – no benefit, and you are not going to use the volume that is required.  So wash out with lots of salty water, then worry about prep later.

Let me know – does this change the way you prep your patients?



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