Each child is different so I would do what works best for the situation and the pt's needs. My 11 year old daughter is asthmatic, she does okay with somethings on her face and not with others. When she had nasal surgery 2 years ago, she freaked out so bad with the NRB, that they had to take me back to recovery to calm her down. I think we all need to be adaptable to the situation and do what is right at the time of treatment. If a four year old can tolerate a NRB, then use one