I do not want to alarm you at all, but one member here did have their Yorkie die after having a tracheal wash.
Here are the threads by that person, one highly respected breeder here does not recommend a tracheal wash for our Yorkies. Please try to find out as much as possible and perhaps get a second opinion if need be before making a decision. Good luck, we'll be thinking of Barney and wishing him well.
Here are the threads:
http://www.yorkietalk.com/forums/sho...=tracheal+wash http://www.yorkietalk.com/forums/sho...=tracheal+wash http://www.yorkietalk.com/forums/sho...=tracheal+wash http://www.yorkietalk.com/forums/sho...=tracheal+wash