Health care is a high-risk profession. Patients frequently die, and sometimes the action or inaction of a doctor or nurse is a contributing factor.

The question is, in health care -- or, in any job that involves danger-- when is the line crossed from an honest mistake to criminality?

Charges of criminal negligence causing death against two Toronto nurses highlights this complex area of law.

Ten-year-old Lisa Shore died in 1998 at the Hospital for Sick Children, when her morphine drip treatment was monitored improperly. She had been admitted to treat nerve pain stemming from a broken leg.

Nurses Ruth Doerksen, 41, and Anagaile Soriano, 25, appeared in court yesterday.

We typically associate the issue of negligence causing death with things like drunk driving. The Toronto case raises the issue of when you can be criminally liable for death, when your job by its nature involves high risk to others.

Civil lawsuits in health care are commonplace. But the standard for proving criminal negligence is much tougher to meet, while at the same time it is a vague standard that Canada's Supreme Court has yet to clarify.

"The whole issue of criminal negligence is fraught with difficulty," said Winifred Holland, a law professor at the University of Western Ontario.

The Supreme Court has ruled that negligence can be both actively doing something (ie. giving a patient the wrong drug) or omitting to do something. The maximum penalty for criminal negligence causing death is life. There is no minimum penalty, unless a firearm was involved in the offence, in which case the minimum sentence is four years. But whether negligence occurs is based entirely on .

A police officer shoots and kills an innocent victim -- but it occurs in the course of a chaotic fire-fight, at night.

A nurse fails to deliver medication to a patient -- but at the time is diverted helping with another patient and there is a breakdown in communication with staff.

To prove criminal negligence causing death on the job, according to legal precedent, a Crown attorney needs to show that an individual's actions were a "marked departure" from the "standard behaviour of a reasonable person," and, in addition, that it exhibited a "wanton or reckless disregard" for lives and safety.

That standard is problematic. Proving a "marked departure" seems clear enough, since it implies nothing about intent. But "reckless disregard" suggests willful negligence -- they knew their actions involved risk.

Holland said it is much easier to prove that a patient's health care, for example, fell below a certain standard, than proving that workers personally must have known the risk but went ahead anyway.

Health care and policing, two high-risk professions (in terms of potential impact on the public) typically discipline their own members through their own professional bodies. But on occasion criminal law is applied. In health care, charges are unusual.

Two years ago, a Windsor nurse was charged with criminal negligence causing death, when she killed a patient by giving an overdose of a drug. The drug itself was the correct one, but the nurse used the wrong vial to deliver it.

She was acquitted of the charge.

Holland said there is a reluctance to charge doctors and nurses, "because there is this sense they are acting in a situation of emergency, doing the best they can. It's not like some person standing on a bridge lobbing rocks at cars. There is no social utility in that behaviour, but there is in the medical profession, so there is tolerance around that."

David Eden, regional coroner for Hamilton-Niagara, said the Windsor case highlights the controversy around the law. He pointed out that, in that case, criminal charges were brought after neither the hospital in question, nor the College of Nurses of Ontario, felt disciplinary measures were required.

"That outcome shows there are different points of view. Errors occur, they are common, so how do you deal with that?"

You can contact Jon Wells by e-mail at jwells@hamiltonspectator.com or by phone at 905-526-3515