One of the hardest parts of a nurse's job is education. You have to make sure that what you're saying is comprehensible and that you're not going too fast for somebody who's already overwhelmed and frightened. You have to be sure that the message is getting across; sometimes, just saying "Don't scrub your incision with a toothbrush" isn't as obvious as it sounds to you, because that person will then go home and scrub their incision with a hairbrush instead (true story).
And one of the hardest things about educating people is that sometimes you come face-to-face with the maxim "A little learning is a dangerous thing".
We all have horror stories about taking care of other nurses, or doctors, or people whose family members are nurses or doctors. The main reason those are horror stories is because people who know *something* about something automatically assume that they know more than they do about that thing. In other words, they try to apply what works for them in their own particular branch of medicine to the branch of medicine they're now dealing with. Sometimes it works. Mostly, it doesn't. It's kind of like trying to install plumbing in a new house when all you've done is fix kitchen sinks for twenty years.
So the education part of the nurse's job gets harder. Most of the time, you're starting with a blank slate in terms of teaching a patient. With people who are medical to start with, you have to correct misunderstandings and revise what they know already before you can get down to the basics.
Nurses have a fun job when they're in this position. See, a doctor or other medical person who's not a nurse will get a totally different picture of what's going on with a patient than the nurse taking care of the patient will. Sometimes the difference is in the details; sometimes it's more overarching than that. Usually the conflict, if there is one, has to do with the nurse's care of the patient rather than, say, a difference of opinion with the doctors on the case.
No, I'm not taking the catheter out. I understand your concerns about a UTI, and I share them, but right now my bigger concern is keeping accurate records of intake and output, because the person in the bed has a condition that causes trouble with their electrolytes. Yes, it is typical to use anticoagulants in addition to mechanical therapies to prevent DVTs, but in this case, anticoagulants could potentially cause harm, so we're going with mechanical therapies and frequent turning. Yes, I agree with you on the pulmonary toilet angle, and I'm going off right now to rewrite the respiratory therapy orders.
It's hard to remember, when you're getting quizzed by the guy with the MD whose daughter is in the bed, that it's not about you. It's about the care that his daughter is getting, and you just happen to be the person in line for questions today. It's also hard not to simply say, "Look; you might know more about allergies/rheumatology/endocrinology/dermatology, but I know more about *nursing*" and leave it at that. It's hard to educate, explain, and clarify with someone who is just as frightened (or more so) and overwhelmed (ditto) than the average bear, yet still keeps jumping ahead of you or going off on tangents.
So what to do? Keep calm. Explain everything, and don't assume that because the person you're talking to is medically-inclined you can gloss over things or skip stuff. Respect their opinions. After all, this is a doctor/nurse/RT/PT/whatever you're talking to; there's a good chance that their knowledge of your patient combined with their knowledge of the sciences will show up things you've missed. Remember that they know more, so they're liable to be more aware of possible complications and Scary Stuff than a layperson. Be kind. It can't be easy to know what they know and be seeing what they see, especially when it's their Baby Daughter/Beloved Husband in the bed. Keep in mind that medical folks are people too and might sometimes forget to eat or sleep, or might just need to be sent home to relax for a while.
And don't act too amused when they express surprise that you know so much about what's going on.