News + Insights

On July 25, 2024, the Court of Appeal for Ontario released its reasons in Hasan v. Trillium Health Centre (Mississauga), an appeal that turned on application of the Supreme Court of Canada's "robust and pragmatic" approach to causation in cases of complex medical negligence.

AGB lawyers, John Adair and Ritika Rai, successfully represented the respondents, Mr. Hasan and his family, on appeal. Mr. Hasan suffered a stroke while in hospital, after the emergency room physician misdiagnosed his symptoms and failed to consult a neurology expert in a timely manner. As a result, Mr. Hasan suffered permanent and disabling injuries.

The trial judge found that the ER physician had fallen below the standard of care, and was liable for negligence. On appeal, the physician argued that the trial judge erred in finding that the physician's negligence caused Mr. Hasan’s injuries because the expert evidence did not establish the exact treatment methodology that would have been employed in the absence of the breach.

At issue on appeal was whether the expert evidence was sufficient to establish that the physician’s breach of the standard of care had been the "but for" cause of Mr. Hasan’s injuries. The Court of Appeal for Ontario upheld the trial judgment and reaffirmed that establishing causation in such cases, despite turning on the "but for" test, does not require scientific proof of causation.

Applying the Supreme Court of Canada's "robust and pragmatic" approach to causation, as applied to cases of medical negligence in Sacks v. Ross, the Court of Appeal upheld the trial judge's determination that it was sufficient for liability that the expert evidence established various treatment options available that would have avoided the extent of Mr. Hasan's injuries, had treatment been provided in a timely manner.

In affirming the decision below, the Court of Appeal made a specific point of confirming that where the defendant's negligence prevents the plaintiff from demonstrating the link between the injury and its causation (in this case, because the doctor's breach of the standard of care resulted in an evidentiary gap), the court can infer causation. That shifts the onus to the defendant to rebut the inference, and any uncertainty will be resolved in the plaintiff's favour.