Mick O'Connor stood pinned against his ambulance by a man holding a knife to his throat.

The paramedic had just rushed to the aid of an elderly man suffering chest pains. Now, suddenly, it was his life on the line.

"I've been in some threatening situations before but, I can honestly say, I thought I was about to die," said Mr O'Connor. "He was a split second away from plunging that knife into me."

In August last year, Joe Berryman, 24, from Heathbrae became involved in a domestic dispute with his father, who then began suffering chest pains.

Mr O'Connor told Fairfax Media that while paramedics arrive at every job with their eyes "wide open", there were no tell-tale warning signs of potential violence as he and a trainee colleague arrived at the scene.

Realising both men required treatment, Mr O'Connor reached inside the vehicle for his radio to inform the Ambulance Service control centre there were two patients.

"As I hung up ... here was the son I was about to assess, marching over, brandishing a massive kitchen knife, with a look of rage in his eyes."

Mr O'Connor attempted to reach inside the vehicle and activate the duress button but before he could press it, Berryman had the knife pointed at the paramedic's throat, interrogating him about whether or not he had just attempted to hail the police.

"I was cornered, a kitchen knife at my neck. My trainee, meanwhile, was in the back. She also had access to a duress button, but given how alert he was, I gave her a subtle indication not to press anything."

As the crisis continued, Mr O'Connor had no choice but to play the role of trained negotiator and attempt to defuse the situation. He later reasoned with Berryman that he was unable to treat him while he was brandishing a knife. "Eventually he agreed to drop it," he said.

Berryman has since spent six months in jail after he pleaded guilty to three charges, including being armed with intent to commit an indictable offence. However, no conviction was recorded in relation to another of those charges, obstruct and hinder ambulance officer in the course of duty.

"I was disappointed with the sentence," said Mr O'Connor, adding: "We exist to help people."

In the past fortnight, the paramedic has again been viciously attacked, this time kicked in the head by a patient under the influence of illicit drugs. The incident, which left him concussed, is now before the courts.

"Each job is a journey into the unknown," he said. "It doesn't matter how prepared you are, there is an element, to the work, that you simply can't train for."

Ambulance Service of NSW Inspector Janine Kiely has witnessed an "almost bizarre" shift in attitude towards her profession, during eight years on the frontline.

"I cannot put my finger on why, but we no longer get treated with the same respect as we once used to."

Ms Kiely revealed that last Monday she had to leave her vehicle at a bus stop so she could rush to the aid of a nearby pedestrian who had been hit by a car.In doing so, she was abused by a woman on the footpath.

"She yelled and swore at me because her bus was due in a couple of minutes and she would be forced to step onto it some 15 metres further down the road," said Ms Kiely, adding: "Abuse, like that, is so routine these days, it seems almost normal. Only now are we learning to say, 'no, it's not acceptable'."

Ms Kiely confessed she had been "reluctant" to take action last November after a man who she had helped revive from a drug overdose suddenly "turned" on her in a busy pedestrian street in Parramatta.

"He threatened to hit me. He then took a swing and tried to punch me. I attempted to climb back into the car but he chased after me ... first around the car and then across the road."

"Pretty scary," is how she described the attack, adding: "I called for urgent police [support]) … but people from a nearby cafe also responded, as did passers-by who stopped their cars … until assistance arrived.

The offender has since been charged with common assault of a paramedic and offensive language. He has pleaded guilty and is due to be sentenced this month.

Ms Kiely said: "I had considered dropping the case but then I thought about my own staff and realised I would have wanted them to pursue it, had it been them. There is currently a real push, within our workforce, to report these matters … otherwise, where does it end?"