Two people stopped to help Mr Tierney and his partner Kim Cooper when his car swerved to the middle of busy Picton Road, south of Sydney, miraculously avoiding other vehicles.
Paramedics happened to be driving by on that day in February 2022 and began first aid, before another ambulance arrived to take him to Liverpool Hospital for specialist stroke treatment.
The second crew was trained to use the Zeus mobile app, allowing direct communication with a neurologist to decide on the fastest course of treatment.
Half an hour after Mr Tierney arrived at the Sydney hospital, he was given clot-busting medication that quickly restored his speech, strength and movement.
"It was just fate," Ms Cooper told AAP.
Zeus has been trialled in NSW, Victoria, South Australia and the Northern Territory since 2021, with stroke experts hopeful of a permanent national roll-out if initial positive results prove definitive.
An app lets paramedics enter medical data while connecting with a neurologist en route to hospital. (Luis Ascui/AAP PHOTOS)
The app allows paramedics to enter symptom information, imaging and medical data while communicating with a neurologist en-route to a hospital.
It "turbo charges" collaboration between medical staff like never before, Stroke Alliance co-chair Geoffrey Donnan said.
"Time is brain when it comes to treating stroke," Professor Donnan told AAP.
"Every second and minute counts, so the quicker you can start treatment the better the outcomes."
Early results from the use of Zeus in SA showed clot-busting medication was delivered in under 45 minutes in 33 per cent of cases in the first eight months of 2024, compared to 17 per cent of cases over the same period in 2023.
There was also a 72 per cent reduction in unnecessary hospital transfers in that state, where eight regional hospitals linked brain imaging to the app in 2023.
Those kinds of advances are critical in rural areas, where the incidence of strokes is 17 per cent higher but very few patients are typically treated in a specialist unit.
"It's upsetting to see how they really are, for a lot of disease process managements, getting second-class service, which shouldn't be the case," Prof Donnan said.
"But with all these technologies, I really see the opportunity to level the playing field."
Amazon Web Services cloud-based technology supports the app's function, securely storing medical records and health data.
Technology was increasingly breaking down geographic barriers to give patients access to better care, particularly as satellite-based internet improved, chief technologist for Australia, New Zealand and Oceania Simon Elisha said.
"The best specialist probably isn't in your city and is definitely not in your suburb, so how do you get access to them?" Mr Elisha said.
"Technology becomes the way to do that."
Mr Tierney has resumed life as a father, grandfather and keen bowls player.
"They saved my life," he said.
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