One of the requirements of those working in the medical fields is that they possess the emotional qualities of empathy and sympathy. There should be a test to determine whether these qualities are in the possession of every new health worker. No one should be admitted to the field without possessing these qualities.
Another needed quality is that of patience. A medical worker requires infinite patience. At the same time, the tendency to express knee-jerk responses to rude patients needs to be completely repressed.
From time to time medical personnel need to be rechecked, reminded of the need for these qualities. Any found wanting should be expelled from the medical ranks.
A degree of numbing occurs to individuals overtime, no matter how strong they may be. However, an uncaring, unsympathetic caregiver, is no caregiver at all.