McGill Faculty of Law: Extra-Contractual Obligations/Torts: Prof. Lara Khoury, 2002-03/Summary by Derek McKee
This test solves the problem of the patient benefitting from hindsight.
Civil law uses “subjectivité rationnelle” (Roberge v. Bolduc, Drolet v. Parenteau):
1. What would the particular patient have done if informed?
2. Would the reasonable person have had the same reaction?
(This is just to corroborate the plaintiff’s testimony.)
Civil law is less concerned with the credibility of patients than common law is.
It it the judge’s task to assess witnesses’ credibility anyway!
Are these two tests different?
There is a slight difference in theory: The civil law test gives more weight to the plaintiff’s testimony.
In practice, both tests have led to the same result: most actions based on lack of informed consent fail on the basis of causation.
Therapeutic privilege is rarely used by Canadian courts: This would allow a doctor to omit information if giving it would cause injury (e.g., psychiatric injury) to the patient.
The Establishment of a Causal Link
Causation and its General Difficulties
(a.1607) states that obligations arise when injury is “an immediate and direct consequence”: however, this is not defined.
Causation has been described as “a tangle, a jumble, a palace of mirrors and a maze” and “squaring the circle.”
Barnett v. Chelsea and Kensington Hospital Mgt. Ctee.,  1 All E.R. 1068 (Q.B.). (CB1p510)
Barnett was one of three night watchmen who came sick to an emergency room on Jan.1, 1966, after having drunk some tea. The doctor on duty, Dr. Banerjee, who wasn’t feeling well himself, thought they had just been drinking and told them (via the nurse) to go home and see their own doctors. It turned out that their tea had been poisoned with arsenic, and Barnett later died.
Was the doctor’s carelessness the cause of Barnett’s death?
Arsenic poisoning is rare, and even if he had been treated, it’s unlikely that the only effective antidote would have been given to him in time to save his life. Thus it cannot be said that that “but for” the doctor’s carelessness Barnett would not have died.
There are three typical kinds of difficulties:
1. plurality of causes: This is when the courts have to pick only one of several possible causes.
e.g. St-Jean v. Mercier
e.g. Gburek v. Cohen
2. uncertainty as to the cause of damage
e.g. McGhee v. National Coal Board
3. when an unidentified person has committed a proven fault (imputation)
e.g. Cook v. Lewis
Approaches to the Assessment of Causation
The causa sine qua non (“but-for” test):
All facts without which damage would not have occurred are causal.
This results in a long list of factors.