Don't read too far into how someone looks at you. She could have been thinking GREAT, now I have to listen to gurgling and keep waking this patient up.....or she could have been thinking....any number of things, as looks are just looks.
Sounds like your report was thorough, you advised MD with no new orders, you asked if any questions, so then at that point, end your shift.
I am an old nurse. And I have had my fair share of looks. I don't pay attention to them, as how am I to know what someone is thinking, if anything derogatory or not.