The incident occurred at about 4:30 a.m. after medical officials responded to a call in Mount Washington, according to a report.
While medics attended to the patient, a man stole the ambulance and attempted to drive out of the city, Pennsylvania State Police and Pittsburgh Public Safety said.
Officers with the state police followed the stolen ambulance in a pursuit that ended when the authorities used spike strips to deflate the front tires of the ambulance.
A suspect, Vincent Scrbacic, 32, was arrested and the ambulance recovered, according to police.
The suspect resisted arrest and was found to have been under the influence of alcohol, the report said.