A group of local researchers hope their new study will help prevent postsurgery heart, stroke and infection risks in older patients.
Even though surgery is overwhelmingly safe and there are enormous benefits from it, complications can occur, particularly in much older patients with underlying comorbidities, Dr. Philip J. Devereaux said.
The McMaster University professor and cardiologist, along with Michael McGillion, Sandra Ofori, and Valerie Harvey, hope that by studying the blood proteins and vitals of 20,000 adults 65 and older, they’ll find the clues that something is about to go wrong.
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An unrelated Canada-wide study of 2007 older adults last year found one in six developed a “new disability” or died within half a year of noncardiac major surgery. It increased to one in five patients by one year.
Through past work at the Population Health Research Institute — which is affiliated with McMaster University and Hamilton Health Sciences — Devereaux and his team found some challenges in preventing complications.
For instance, the pain medications people get after surgery, like narcotics, can mask symptoms that might otherwise indicate a problem. This can mean “substantial delays” in addressing it, he said.
The group helped design a special Vitaliti monitor which can continuously measure vital signs, like heart rate and rhythm, blood pressure, temperature, oxygen saturation, respiratory rate, body position movements and even sleep analysis.
Participants of the VISION-2 study will put it on just before surgery. It will be put back on just as patients leave the OR after surgery to be worn for the next 30 days.
They anticipate around 800 people in the study will develop sepsis (a life-threatening response to infection). They’ll match them to the same number of patients who are of similar age, sex and type of surgery who don’t develop sepsis.
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The researchers will use AI to identify “the pattern of changes in biophysical parameters” that happen six, nine, and 12 hours before the clinical diagnosis of sepsis, Devereaux said.
This will help them see how the biophysical parameters change every couple of hours before the clinical diagnosis of sepsis, so they know when and how to intervene.
They will use the same process to learn how to identify early clues of heart ischemia (where the muscle is not getting enough oxygen), “and we will do the same thing for other major complications,” he said.
Part of the study will involve identifying the novel biomarkers that can indicate a post-surgical stroke is occurring.
Using MRIs, the group identified a new covert stroke that can happen after surgery in seven per cent of patients 65 or older having non-heart surgery. They found these “silent” strokes increased the risk of cognitive decline at one-year post-op.
While an MRI can detect this, it’s too costly to automatically give one to every patient after surgery — “it’s hard enough to get the money to do it for research,” Devereaux said.
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Because Hamilton has unique technology that allows them to measure up to 5,000 proteins in blood, they will also collect blood samples before and for the first few days after surgery.
This should help them understand the biological pathways associated with perioperative complications and predictors and prognostic markers of perioperative complications, he said.
The study will begin soon in Hamilton, and they’ll be recruiting patients undergoing surgery at local hospitals and other international hospitals.
