How Rebreathing circuits, Ventilator parts and Incubator humidifiers are examined for cleanliness and items with limited life are processed with SSD policy.

You cannot look into the lumina sure. If these utensils are prepared in a WD it is important that all lumina are flowed intensively. You can check this with TOSI Lumchecl cleaning indicator as far as it can be fastened at the end of a tube or a channel.
The other way is to test for protein residues with the Biuret method. You flush the lumen with 10 - 20 ml SDS solution and add 1 ml to a mixture of the biuret chemicals.
Both methods are described in "Qualtätssicherung von Reinigungs- und Desinfektionsprozessen", Behr´s Verlag Hamburg and in 3M "Sterilisation.
Both only in German language.

Sigrid Krüger