A US judge told the state of Tennessee to preserve all evidence related to the failed attempt to execute Christa Pike, who lawyers say is "angry and confused" after waking up in hospital nearly a week after the ordeal.

Pike, who was sentenced to death for torturing and killing classmate Colleen Slemmer in 1995, survived despite being given two lethal doses of pentobarbital, a lethal injection drug.

What do we know about Christa Pike's current state?
One of her attorneys spoke about the 50-year-old's state after the failed execution.

"She is angry and confused about everything right now," Randy Spivey said during a news conference, adding Pike is "very aware" of what was done to her.

"She cannot move either of her arms, both of her arms and hands are tremendously swollen, and we do not know what, if any, function she will regain in her arms," Spivey said, adding that "there's a long road ahead" for her recovery.

Pike is the only person known to have survived after receiving lethal injection drugs, according to the Death Penalty Information Center.

Luke Ihnen, another lawyer for Pike, said that "medical staff have asked that the shackles be removed and have been denied that request."

Her lawyers continue to demand that Tennessee Governor Bill Lee commute Pike's sentence to life in prison and never reattempt her execution.

The Republican governor had denied a clemency appeal two days before the failed execution.

Pike's recovery period unclear
Experts say it is possible that the failed execution was due to a problem with the IV line that caused the injection to pool in her tissue rather than enter her bloodstream.

"Apparently at no point did any member of the execution team realize that the IV lines were not correctly placed or that the veins had blown," her attorneys wrote in their court filing.

Pike's arms were burned and blistered due to the injection, according to her legal team, who are demanding that the prison authority holds all information from the attempted execution, including needles and execution logs.

It is not yet clear how Pike's recovery might unfold and whether she will be subjected to another execution attempt.