I'm interested in all the above comments. From a theoretical view, all of the moisture breathed out by the patient should be picked up by the HME and then re-breathed in. Therefore, very little moisture should find its way to the anaesthetic machine side of the HME. It would be interesting to note what happens when the HME is replaced by a bacterial filter.
Just one further point that Geoff raised regarding an HME in an anaesthetic circuit; the HME could have the reverse effect on the vapourised anaesthetic agents and cause the "rainout" that is being seen, but only if the "moisture" levels and temperature are similar to that seen on the patient side of the HME.
Let's see what Kev finds out??!!!!!
