The highly anticipated decision, hailed as a victory by some religious groups, upholds existing legislation in Ontario and several other provinces.
But it does little to resolve some of the more intractable ethical dilemmas posed by advances in modern medicine that allow patients in vegetative states to be kept alive for years.
In a 5-2 split decision on what the top court called a "tragic, yet increasingly common conflict," Chief Justice Beverley McLachlin wrote for the majority that, in provinces where such laws exist, disputes over end-of-life care decisions must go to independent tribunals or courts for resolution — and are not the sole purview of either doctors or patient's families.
Those independent tribunals may take into account non-medical factors, including the moral, ethical and religious views of the patient and their family.
Justice Andromache Karakatsanis, in a dissenting opinion, argued that Ontario's Health Care Consent Act does not "give patients, or their substitute decision-makers, the right to insist on the continuation of treatment that is futile, harmful, or contrary to medical standards of care."
The case involves 61-year-old Hassan Rasouli, who has been kept alive on a ventilator and feeding tube since brain surgery in 2010 went wrong.
Doctors at Toronto's Sunnybrook hospital have determined there is no therapeutic hope of recovery and that keeping Rasouli on life support will result in a series of progressively worse medical complications.
However, Rasouli's wife, Parichehr Salasel, refused consent, citing the couple's Shia Muslim religion and a belief that her husband's movements indicated some level of minimal consciousness.
Salasel screamed in approval Friday when the decision came down, saying she was "happy for all humans because we are, as a human, on top of the creation of God." She maintains her husband is responsive.
The Supreme Court elected not to wade into the intersection of science and faith, ruling simply that Rasouli's doctors couldn't do an end run around the Ontario Health Care Consent Act.
The "treatment" provisions of Ontario's law cannot be confined to something that doctors say is of therapeutic benefit to the patient, said the court.
"While the end-of-life context poses difficult ethical dilemmas for physicians, this does not alter the conclusion that withdrawal of life support constitutes treatment requiring consent under the HCCA," McLachlin wrote.
"If death is considered harmful or a manifestation of ill health, then life support serves a preventive purpose so long as it is effective in preventing death," the court dryly observed.
The ruling revolves around a statutory interpretation of Ontario's consent act. Similar legislation exists in five Canadian provinces.
"All the Supreme Court decided is that if you two disagree, please follow the procedures that are in place already," professor Udo Schuklenk, the Ontario Research Chair in Bioethics at Queen's University, said in interview.
Erica Baron at McCarthy Tetrault, a lawyer for one of the two doctors in the Rasouli case, said the court had provided "clarity" on when Ontario's law applies.
"Before this, our doctors were guided by the medical standard of care as well as well as College (of Physicians and Surgeons) and hospital policies," said Baron.
The ruling highlights a murky area for doctors and patients in provinces that do not have patient consent laws.
Jocelyn Downie, a bioethicist at Dalhousie University in Halifax, said other jurisdictions should take note and introduce a statutory regime that can both enhance patient autonomy and ensure proper care.
McLachlin, in her ruling, noted the judgment does not resolve who should have the ultimate say in end-of-life decisions in the absence of such legislation.
"Nor does the case require us to resolve the philosophical debate over whether a next-of-kin's decision should trump the physician's interest in not being forced to provide non-beneficial treatment and the public interest in not funding treatment deemed of little or no value," McLachlin cautioned.
That didn't stop Rasouli's family and some faith groups, including the Evangelical Fellowship of Canada, from claiming the ruling as a victory for religious rights.
Dahne Jarvis, who specializes in litigating health law with the Toronto firm Borden Ladner Gervais, said religious groups are reading too much into the judgment.
Experience shows that Ontario's consent and capacity board, which adjudicates consent disputes, has "not allowed religious beliefs to trump any of the considerations and factors that are brought to bear on what is considered to be in a patients' best interests," Jarvis said.
The high court has not decided "that everyone has the right to whatever treatment they choose at the end of life," Jarvis added.
"All they've decided is what process should be engaged."
— With files from Helen Branswell and Colin Perkel
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