Christa Pike was in critical condition in a Tennessee hospital after an attempted execution by lethal injection, her lawyer said.

Pike, who was convicted of murder, received two doses of pentobarbital on Wednesday, but they did not stop her heartbeat, according to her legal team. As of Thursday night, she was unconscious and on a ventilator. Her lawyers said prison staff used at least seven needles while trying to establish intravenous lines and alleged that the lines were not properly placed.

Governor Bill Lee has ordered a third-party review and halted Tennessee executions for the rest of the year. The state's prisons chief is also resigning. Pike's lawyers filed an emergency motion Friday to preserve evidence from the attempt.

The Tennessee Department of Correction defended the method it used, saying its protocol did not permit further procedures. Pike's lawyers had challenged the lethal injection protocol in January, citing a blood-clotting condition and difficulty placing needles in her veins.