Dr. Paul Dowhanik told an inquest he had no reason to suspect Heather Brenan had a blood clot which an autopsy later showed killed her. Brenan showed no tell-tale signs such as swollen or red limbs.
"Her presentation was not of those symptoms," he said.
The inquest is examining the treatment Brenan received at Winnipeg's Seven Oaks Hospital at the end of a three-day stay in January 2012. Brenan was 68 and had health problems that included hypertension, diabetes and poor kidney function. She was described as morbidly obese with a body mass index of 49. A normal index is between 19 and 25.
Brenan was sent home by taxi, collapsed on her doorstep and was rushed back to hospital.
Dowhanik said he decided to discharge Brenan because tests showed her kidney function was improving and there were no signs of trouble with her heart or white blood cell count.
"Overall, these lab results were reassuring."
Brenan had originally come to the hospital because she had been unable to swallow and had lost 40 pounds. Tests showed no physical blockage of her throat or chest cavity, Dowhanik said, and Brenan had begun to feel better.
He added that she was able to get out of her hospital bed, move around on her own and no longer required oxygen to do so.
"I do recall ... her standing at the (nurses') desk, looking over and talking to somebody," he said.
"I found her to be comfortable and not in any distress."
The hospital had arranged for a friend to meet her at her door because she did not have her house keys. She collapsed, an ambulance arrived in about four minutes and she was rushed back to Seven Oaks.
"I was pretty startled that it was the patient that I had just discharged," Dowhanik recalled.
Brenan had regained a pulse, but was unresponsive. She was later pronounced dead.
Dr. Susan Phillips, a pathologist who performed the autopsy, testified that Brenan had deep vein thrombosis and had a number of blood clots in her legs that could have been hard to detect.
One clot travelled to the main artery between Brenan's heart and lungs and lodged there, causing her death, Phillips said. It would have happened immediately before the woman collapsed.
"It could not have been there very long before it would cause symptoms."
The Winnipeg Regional Health Authority has suggested no one could have predicted Brenan's death and it would probably have occurred whether or not she was in hospital.
Brenan's family has said the woman never should have been sent home because she was too ill. A diagnostic test earlier that day that involved putting a tube down her throat had been cut short because she had trouble breathing, the inquest was told earlier this month.
Brenan was one of three Winnipeg residents who died, within months of each other, after being sent home from hospital by taxi.