William D.T. Carter

The appellants appealed a jury verdict dismissing their medical negligence action arising from delayed diagnosis and treatment of an anastomotic leak following routine bowel surgery, which resulted in septic shock and bilateral below-knee amputations.

The jury found five defendants breached the standard of care but that none of the breaches caused the injuries.

The Court of Appeal addressed the proper causation test in delayed diagnosis cases involving multiple tortfeasors, finding that the trial judge's use of the word "necessary" from Clements in jury questions and instructions was problematic and that the phrase "caused or contributed to" should not have been rejected.

However, the court held that the jury clearly accepted the defence theory that a rare necrotizing infection, not the delay, caused the injuries, and no reformulation of questions or instructions would have changed the verdict.

In a jury trial for medical negligence arising from hospital treatment, the parties disputed the proper wording of causation questions to be put to the jury and whether the jury should provide particulars explaining any finding of causation.

The plaintiffs argued the jury should be asked whether the defendants' breach 'caused or contributed to' the injury, relying on principles recognizing multiple causes in negligence.

The defendants argued the jury must be instructed using the Supreme Court of Canada’s 'but for' causation test articulated in Clements.

The court held the jury questions should follow the 'but for' formulation, finding the 'cause or contribute' wording risked confusion.

The court also ruled that if causation were found, the jury should be required to provide particulars of its reasoning due to the complexity of the medical evidence and multiple defendants.