The anesthesia machine with the feather

I'm in the OR and the ventilator is breathing for the patient, but there's a small white feather floating just above the vaporizer. It moves up and down with each cycle, like it's counting along. I want to tell the surgeon to look, but I know if I speak, the feather will fall. We all just stand there, breathing together, and it's the calmest I've felt in weeks.