My husband was in the hospital last month and they couldn't wake him up when he first arrived. They were drawing blood, and shouting to try and wake him. I asked the nurse if he was comatose. And she said no. He did eventually wake up, but nobody could tell me why he was sleeping so long and why he couldn't be awakened. Lately, this sleeping pattern has occurred at home also. Any thoughts?
Have you discussed with PC to have the meds reviewed? Maybe the pharmacy can review them to make sure they are not reacting in an adverse manner.
With oxygen use, one possibility is hypercapnia where CO₂ builds up when breathing is too shallow. This can cause extreme sleepiness, confusion, hard-to-arouse state. It's very common in people with COPD or chronic lung disease, especially if they are on sedating meds and/or oxygen flow is too high or not well balanced.
Medication interaction can cause problems as well.
What did the hospital/doctor say once he woke up and they examined him?
Do you keep a journal with his details in it? We had a notebook for mom that we recorded what she ate, when, how much, bathroom tracking, medicine, wake up times and bed. Any changes of meds stuff like that. Fell on such a day. It doesn't have to be indepth or fancy. We just used a spiral bound notebook. The reason i say this is you can then go back and look at things for patterns. Like, oh, look there is always a stomach problem when my mom eats too much cheese before bed 2 nights before. Or, when I give meds at this time it is more helpful.
My mom is a super heavy sleeper after any stress or trauma. Plus she’s very hard of hearing without her hearing aides. It’s her way of recovering. After her fall last year it was noted as unusual while she was in the hospital but seemed normal for her to me. She had no sleep inducing meds.