A think with a 3 year old you would probably do a cupping/clapping technique….but I am not sure, The take home message is ask your doc about it - and hopefully get a referral to a physiotherapist who is used to dealing with children with chest issues. I do think a 3 year old might be able to do what my daughter does. This is what he does:
1. She breaths into a device called a PEP machine. It was about 40$. She is supposed to blow into it 15 time, hold it for 3 seconds, and she has to blow at a suffecient pressure that a needle goes into a orange zone.
2. She then huffs 5 times - so pretends she is fogging a glass 5 times
3. She then coughs 3 times. Yes, fake coughs. Sometimes they turn into real coughs and sometimes I can hear secretions moving - which is the goal in her case.
I think the plan DD is on is best for people who tend to have secretion get stuck in one area (and that turn into a chest infection). This helps move secretions around.