Thanks for the info. 4 year old was the one with 93% a few times that I took it this afternoon and then again at bed time. He does have a cold so I think that would explain it. He has never had an asthma attack - more night time cough and very quick to tire with activities. Dr has told me he's asthmatic but I wasn't sure. He is on daily preventative tablets (has been for 2 years now) but I wondered if they were still necessary. Will see what the dr says When I see him.