A stroke patient who is clearly deranged due to the stroke arrives to ER. The patient is not listening to instructions and acts out. The patient is told to stay on the bed and not to get up and left unattended. The patient gets up, falls face down, and breaks her nose. The broken nose weeks later complicates treatment. Is the ER liable?
This would be a question of fact for a jury, informed by expert testimony, to evaluate. There is no one correct answer and it is a mixed question of law and fact. The jury is given a very broad legal standard and has to apply it to the facts. The jury is not told how other cases with similar facts have been resolved by previous juries and the judge and appellate courts can't consider how factually similar cases were decided on the disputed factual issues either.
Some of the key mixed issues of law and fact would be:
Duty: Has a medical professional-patient relationship been established, and if so, with whom?
Negligence: Did a medical professional who had this person as a patient fail to act with the care of a reasonable medical professional of this type? This would be mostly a question of fact for a jury to resolve on a case by case basis based upon expert testimony particular to that case. Also, there are some circumstances when a gross negligence rather than a negligence standard would apply based upon specific state tort reform laws. I have no idea what reasonable medical professionals would do in these circumstances. Factors like how busy the ER was at the time would also be relevant.
Causation and Injury: To what extent did not taking the act alleged to be negligent and found by a jury to be negligent cause an injury and if so, how much of the harm was attributable to that negligent act as opposed to the underlying condition for which treatment was sought? This would be primarily a question of fact to be resolved based upon factual and expert testimony.
Was was the relationship of the patient to the ER and to the medical professionals who were allegedly negligent? What was the relationship of the medical professionals involved to the ER? What does state law say about the responsibility of this particular hospital (which might be private, state and local, or federal) for medical malpractice by medical professionals providing services in the ER? If the entity to be sued is a governmental one, what exceptions to sovereign immunity apply in this jurisdiction for this type of entity? Most entity liability is vicarious due to acts of negligence by its employees and agents. But sometimes entity liability is direct due to having bad policies in place that are negligent across the board for an entity of that type to have in place.
Did the patient have comparative fault? In many states the jury is charged with allocating what percentage of fault is due to each party, when multiple people (including the "victim") are negligent, and not with an all or nothing negligence determination. If the patient was deranged due to voluntary intoxication or drug use or just being stubborn and ornery, the jury might attach some percentage of comparative fault to the patient.
Did the patient fail to mitigate damages? A related issue to comparative fault is that the patient has a duty to use reasonable efforts to minimize the amount of injury that the patient suffers, for example, by following doctor's orders. This is rarely a complete defense and probably wouldn't be in this case, but the defendants being sued could argue, for example, that some of the broken nose related complications in the treatment were due to not following discharge instructions properly, rather than necessarily from the broken nose itself.