An excellent question to ask, bravo!
The "Prudent Nurse" standard is a legislative catch all phrase used to determine whether or not there is culpability on your part in a malpractice claim. The standard essentially compares your actions to those of a similarly trained "Prudent Nurse" under the same circumstances.
What one "Prudent Nurse" would do over another for the purposes of this thread is in itself, a likely subject of debate. However, consider that a Judge (as well as a jury) are in fact laymen where medical issues are concerned.
Therefore, presented with evidence and expert testimony, what the layman would consider prudent, is your safest bet.