Christa Pike's execution failed. Here's how lethal injection works

Lethal injections are under scrutiny after Christa Pike survived two rounds of drugs during Tennessee's failed attempt to execute her.Why it matters: Lethal injection has been the dominant U.S. execution method for decades, accounting for roughly 89% of the 1,683 executions carried out since 1976, per the Death Penalty Information Center.Driving the news: Pike, convicted of killing a classmate three decades ago, survived two rounds of lethal injection drugs Wednesday in what would have been the state's first execution of a woman in 200 years.In response, Gov. Bill Lee halted executions and ord