A healthcare provider may be prosecuted for involuntary manslaughter if all of the following are present:
(1) The death of a patient or co-worker.
(2) The person died as a result of a dangerous act (capable of causing serious bodily harm or death) done by the defendant.
(3) The defendant acted recklessly (deviated grossly from the standard of conduct observed by a law-abiding person or a competent healthcare provider).
(4) The defendant was not acting intentionally to harm the patient.
(5) The evidence for #2 and #3 is beyond a reasonable doubt.
If the defendant intentionally meant to harm the patient then it would be considered a more serious form of homicide (first degree murder, secondary murder, voluntary homicide).
It is always tragic when someone dies as a result of a healthcare misadventure, but some cases prosecuted for manslaughter seem to be motivated for some reason other than justice.