Christa Pike remains critically ill after failed execution

Christa Pike remains critically ill and unconscious in a Tennessee hospital after surviving a failed execution attempt, according to her lawyers.

Pike has been placed on a ventilator and intubated while medical staff in Nashville work to stabilise her condition and remove pentobarbital from her system, her legal team said in a court filing.

The filing provides the most detailed account so far of Pike's condition since she was taken by ambulance to hospital on Wednesday following the botched lethal injection at a Tennessee prison.

Her lawyers said Pike suffered severe injuries to both arms during the execution attempt. When she arrived at hospital, they said, both arms were swollen, burned and blistered.

The lawyers allege that problems with the intravenous lines prevented the pentobarbital from entering Pike's bloodstream as intended. They claim members of the execution team failed to recognise that the IV lines had been incorrectly positioned or that Pike's veins had collapsed.

According to the court filing, prison officials then prepared a backup set of syringes and administered what her lawyers describe as another lethal dose of pentobarbital.

Pike's legal team has argued that the failed execution subjected her to what they described as "chemical torture" and is seeking to have her death sentence commuted to life imprisonment.

Pike was sentenced to death after being convicted of torturing and murdering a young woman in 1995. She was 18 at the time of the crime.

If the execution had been completed, Pike would have become the first woman executed by Tennessee in more than two centuries. She was also the only woman on the state's death row.

Her lawyers filed an emergency request seeking to preserve state records and evidence relating to the execution as questions continue to surround the failure of the procedure.

Tennessee Governor Bill Lee has suspended all executions in the state for the remainder of the year while officials investigate what went wrong.

Pike's condition remains critical as doctors continue efforts to save her life.