8yo sleeping heartrate now always 115+, sets off hr alarms nightly (150+). until month ago, noc hr was 78-80s with dips under 70. concern? no fever

YES!: I am not sure why your 8 year old is on a heart rate monitor at night but it is a fortunate situation as you might otherwise not have known about this. Your child needs to be seen by a physician as soon as possible. This is not a normal condition. My immediate concerns are:possible partial airway compromise via trach, possible myocarditis, subclinical pneumonia etc. .