You can read a little about Collapsed Trachea, and Reverse Sneezing here at my site. Here are the addys for the information. You can find a short synopsis of several different problems on this page,
http://yorkieviews.com/healthfacts.htm , including the Trachea and Sneezing problems, and then you can go here for more information.
http://yorkieviews.com/trachea.htm and
http://yorkieviews.com/reversesneezing.htm