A patient tried to hack a paramedic's ear off with a meat cleaver, causing a moving ambulance to hit a parked car.
Paul Searle pulled his victim from the vehicle before grappling with him on the ground while wielding his weapon, Portsmouth Crown Court was told.
He was overpowered after a second paramedic leapt out to go to her colleague's aid.
Searle left the first paramedic with a cut hand, while the second had a lump on her head.
The 59-year-old, of St David's Road, Southsea, Hampshire, was convicted of grievous bodily harm with intent after admitting attacking an emergency worker.
He was remanded in custody and will be sentenced on December 16.
The ambulance was called to Glenesha Gardens, Fareham, in the early hours of February 11 2021 after Searle began to suffer breathing problems, Hampshire Police said.
"Despite the efforts of attending paramedics to help Searle, he became aggressive and verbally abusive to the point that the emergency workers left the address and returned to their vehicle," a force spokesman said.
"Shortly after, Searle approached the ambulance armed with a meat cleaver and pulled the driver out of the vehicle whilst threatening to cut his ear off.
"The ambulance was reversing at this time and ended up colliding with a parked car.
"The second paramedic, who had been in the passenger seat, then radioed for assistance and got out of the ambulance to find her colleague grappling on the pavement with Searle, before she assisted in restraining him.
"As a result of this incident, the ambulance driver suffered a cut to his hand from the meat cleaver which required stitches, while his colleague sustained a lump to her head."