SAN DIEGO -- A man with a history of DUI convictions pleaded not guilty Wednesday to felony charges for allegedly stealing an ambulance at Sharp Memorial Hospital and leading police on a 12-minute pursuit around Clairemont.

Paul John Sos, 52, was ordered held on $75,000 bail.

Deputy District Attorney Renee Palermo told Judge David Szumowski that Sos went to the hospital about 5 a.m. Saturday and drove away 90 minutes later in the ambulance. The prosecutor said the keys were left in the vehicle, and it wasn't noticed missing until about 15 or 20 minutes later.

Palermo said the ambulance was spotted and police gave chase with lights and sirens activated. The prosecutor said Sos ran at least six red lights and stop signs before hitting a spike strip that flattened the tires of the ambulance.

The defendant's blood was drawn after his arrest, but the results are not yet available, the prosecutor said.

She said Sos has three prior felony DUI and three misdemeanor DUI convictions.

In the current case, Sos is charged with felony DUI with alcohol or drugs, DUI with a blood-alcohol level of .08 percent or higher, auto theft, receiving stolen property and evading police with reckless driving, and a misdemeanor charge of driving on a suspended license.

The judge set a readiness conference for April 16 and a preliminary hearing for April 20.