Hours after three paramedics were injured while trying to assist a patient who became violent at a home in southwest Calgary, a standoff ended when a police robot was sent into the house and a man was taken into custody.

EMS spokesman Adam Loria said the three paramedics — two men and a woman — responded to a call in the community of Parkhill at 8:03 a.m., and the patient they were attending to suddenly became aggressive, likely due to an "illicit substance" in his system.

"It escalated very quickly. We were probably in that residence for no more than 60 seconds before this occurred," Loria said Thursday afternoon.

"In our attempt to immediately retreat from that residence … we had to use self-defence, and some physical confrontation did occour."

All three paramedics were taken to Rockyview hospital, Loria said, with what were believed to be relatively minor soft-tissue injuries.

Police later said one of the paramedics suffered a broken finger in a struggle with the man.

Police vehicles and armed officers outside the home in southwest Calgary where a man was holed up. (Evelyne Asselin/CBC)

Officers responded to the residence and spoke to the offender, who was holed up inside the home, for hours through a loudspeaker, trying to convince him to come out.

"What we do is we try to de-escalate the situation and make sure that everybody is safe," said Staff Sgt. Peter Siegenthaler.

Numerous Calgary police vehicles and officers with rifles were seen in the vicinity of Stanley Road and 39th Avenue S.W. throughout the morning.

Police send in robot, then armed team

Around noon, an armed police team along with a police dog entered the home and took the man into custody.

Police said that decision was made after police sent a robot into the home, which located the man inside one of the bedrooms.

"At this point we weren't sure if he was in medical distress or not, so at that point our team moved in and took him safely into custody," Siegenthaler said.

Police escort a man out of a home following an hours-long standoff that began when three paramedics were injured in a struggle with a man they were trying to assist in southwest Calgary. (Jennifer Lee/CBC)

The call initially came in as a heroin overdose, he added, and the man was taken to hospital to be examined.

The man is facing charges of assault, assault causing bodily harm and forcible confinement.

Loria said the three paramedics were released from hospital later in the day.

"Very scary time for all involved. Our thoughts are with them and their families," he said. "The crew and family were offered debriefing opportunities as well as counselling, if required."

Paramedics are trained on how to defuse violent patients and are issued protective equipment.

"The first thing you want to do is get out of that situation safely, like we did today, and let the professionals — that being the police — take over."