Don Cruse, who writes the SCOTX blog, has a good discussion of the new rules for permissive interlocutory appeals.
I don't know how often we will have occasion to use this procedure in medical malpractice cases. One scenario that comes to mind is a Motion for Summary Judgment based on the statute of limitations. It's a question of law and early resolution of the issue could result in termination of the litigation. It seems that you could make a case that resolving whether the SOL had lapsed was an issue that should be decided on an interlocutory basis, possibly avoiding preparing and trying an entire case only to have the whole thing reversed on appeal.