Mom Is 92yrs Old ...she Went Hospital 2 Was Ago

Mom is 92yrs old ...she went hospital 2 was ago overnight. ..they upped usage of cpac (oxygen) to 24/7...doing fine now with oxy. Also increased her dosage of cartia to 240mg from 180mg. Went to followup with prime dr yesterday...her BP was 93/57, so prime drsaid go back to 180mg until she reviews with cardio next wk. today she took the 180mg and her BP was 112/48 (however her home metro might be off on diastolic about 10 low) right after waking from nap ... will try in little while with my BP meter to compare. How concerned should I be about low diastolic ... she has always seemed on the low end, but not quite that low.