It's an ICU. The work you're doing is important and it sounds like so far you've been patient and showed maturity despite your coworker and her words. That's awesome; you're proving you're fit for a role in a stressful and fast paced environment.

There's no room there for her passive aggressive BS in an ICU, though. Teamwork has to be job #1.

So I would probably ask to speak to your boss privately and express your concern at the hostile work environment your fellow clerk is creating. But when you do this be dispassionate, calm, specific with dates/times/quotes of what was said to you.

Otherwise, ignore her as much as possible, and you focus on being the best you. And let me just say thank you for all you do, good unit clerks really helped me out so many times when things got wild at work.

From a former ICU RN