A judge gave a former nurse who killed at least 29 patients in two states six more life sentences, raising the total to 18, after a hearing in which the defendant had to be gagged with a cloth and duct tape.

Charles Cullen, who committed one of the worst murder sprees ever discovered in the U.S. health care system, spent 30 minutes repeating the sentence, "Your honor, you need to step down," hundreds of times.

Cullen, who was sentenced last week to 11 consecutive life terms in New Jersey, administered lethal overdoses to seven patients at nursing homes and hospitals in Pennsylvania, and tried to kill three others.