Employees from a Mid-City convenience store put the restrictive parking boot on the ambulance.
The paramedics worked on the patient with chest pain, put him inside the vehicle, then started to speed off.
New Orleans Emergency Medical Services spokesman Jeb Tate told WWL-TV the paramedics tried to drive away, but couldn't. When the boot was removed, the tire was flat, forcing paramedics to call another ambulance to pick up the patient.
Tate said the ambulance had its emergency lights on the whole time.
Signs in the parking lot at Quicky's convenience store warn that parking is for customers only and that the store will boot vehicles.
Store employees declined to comment.