The Yorkshire Ambulance Service worker, who was handing over at the nurses' station after dropping off a patient, was knocked to the floor by a man who punched him in his head from behind.
APPEAL: Police search continues for man wanted over Sheffield murder He said he knew nothing of the attack until he regained consciousness a short time later.
The culprit was arrested at the scene by a police officer already at the hospital dealing with another patient.
The shocked paramedic, a 39-year-old dad-of-two from Doncaster, was assessed by medics and underwent X-rays and a CT scan.
He said he was fortunate not to have suffered a serious head injury.
'The potential consequences of this could have been much more serious. You hear of one punch killings when people smash their head on theÂ ground, and this could easily have happened to me,' he said.
'I had my back to the man who did this as I was handing over at the nursers' station but apparently he was frustrated at how long he had been in the waiting room, ran towards me from behind and punched me to the side of my face.
'The first I knew of it was when I came round to find myself laid on the ground with a commotion around me.'
'Fortunately the police were already in theÂ department and arrested the man thereÂ and then.'
The paramedic said the attack resulted in the loss of an ambulance that night.
'The knock-on effect of this was that an ambulance was off the roadÂ for the rest of the night when we are already stretched and the NHS had to pick up the cost of the X-rays and CT scan I needed as well as the hospital staff who looked after me,' he said.
'People need to think about the consequences of their actions. Our ambulance might have been really needed that night by somebodyÂ seriously ill.'