Always in our hearts: Following an automobile accident, Lakers head coach Frank died instantly in the hospital.

Derrick Thomas, the Kansas City Chiefs’ Pro Bowl linebacker known for his ferocious play on the field and his charity work off it, died unexpectedly yesterday morning in a Miami hospital, 16 days after a car crash had left him paralyzed from the chest down.

Doctors said Thomas suffered from cardiorespiratory arrest while being transferred from his bed to a wheelchair on his way to a therapy session.

Thomas’s death surprised the doctors who were working closely with the former National Football League star. Dr. Frank J. Eismont, a neurosurgeon at Jackson Memorial Hospital in Miami, said he believed that Thomas died from a pulmonary embolus, which is a blood clot traveling through the lungs. The 33-year-old linebacker had been taking blood thinners and wearing compression stockings to try to prevent such clots, Eismont said, but that doesn’t always keep them from occurring.

”This is a total shock,” said Dr. Barth A. Green, chairman of the department of neurosurgery at Jackson Memorial. ”We had a medical team there within seconds, but there is nothing that could be done.’