The first few weeks in the unit, I thought I'd never get through it, suctioning vent patients and all those secretions! (barf!) for me it was not looking at it that made me sick, it was the sound of it, although at times it was both. One of the RT's got a cup of water and made me use the yankaur to practice with, pretty soon it didn't bother me as much. Without this I'd still be gagging everytime. Maybe this would help you too????
The bad news is, now I've gotten over suctioning and moved on to total nausea over cleaning food filled dentures........