The failed execution of convicted murderer Christa Pike was the second failed execution in Tennessee this year.

The head of Tennessee's prison system is resigning, Gov. Bill Lee announced Saturday, the first major shake-up since the stunning failed execution of Christa Pike landed her on a ventilator at a hospital.

Prison commissioner Frank Strada insisted his team followed protocol, even after two doses of anesthetic failed to kill convicted murderer Christa Pike. He is set to leave his post this month.

Lawyers for Christa Pike said she's unconscious and on a ventilator after a botched execution attempt. Pike is believed to be the first person to have survived the administration of lethal drugs in the modern era.