Our experience with a bounce house scared me to death!! Abby played in there for about 5 minutes before coming out coughing so hard that she could hardly catch her breath! And no she was not sick at the time. I didn't have my albuteral with me and I was seriously scared more than I have ever been scared before that she was not going to be able to catch her breath!! I talked to her CF team and they said that more than likely the germs in there were being bounced all around and she breathed them in and they irritated her airways and so her body was trying desperately to get rid of what ever she inhaled. She has never been in a bounce house since nor does she even want to and she is 7. It scared her pretty bad too.
The only time I ever somewhat willingly left a bounce house was when I twisted my ankle in one, and I only left them because it was either bounce and cry or get ice cream and cry. Other than that, I went in every bounce house I could. It is fantastic exercise and I can't remember ever getting sick after playing in one. My only suggestion would be to wipe down hands as soon as your child gets out of the house with hand sanitizer.