is requesting a new preceptor appropriate?

Even if you'd had 10 years' experience on med-surg, I don't think you should be expected to take on 3 sick MICU patients independently on your THIRD ORIENTATION SHIFT! What was he thinking? Oh, maybe I can get someone else to do all my work today? Definitely talk to the educator. That's just plain abusive. I'd want to know how that preceptor was chosen for you, because obviously something got overlooked. And I'd also want to know what their standard is for orientation. Good luck...

I agree that you are being expected to do WAY too much for the beginning of your orientation. My recommendation would be for you to sit down with the educator on your unit and ask her/him to clarify what the expectations are before jumping to any conclusions. It your preceptor is simply expressing the usual expectations, then switching preceptors will not help. If that is the case, then you may want to switch jobs before you invest too much in this position. On the other hand, if your educator says that the expectations are for you to have 1 or 2 patients with lots of help, then you can bring up your preceptor's expectations and ask for advice on how to handle the situation.

In politics (as well as in patient care) it's usually best to do a thorough assessment and get all of the facts before jumping to conclusions and taking action prematurely. While we all know the nursing process, sometimes we forget to use it when we are in the middle of a troublesome situation.