Washington (United States) (AFP) - The woman who survived a failed execution in a US prison last week is now conscious and speaking, but her prognosis remains unclear, her lawyers said on Tuesday.

Christa Pike, 50, who was sentenced to death for a murder she committed when she was a teenager, received two supposedly lethal doses of the drug pentobarbital at a Tennessee prison a week ago.

She survived the injections, however, and was rushed to hospital, where she had been unconscious and on a ventilator in critical condition.

Pike’s lawyers said on Tuesday that “against all odds” she was now “conscious, speaking, and continues to receive critical medical care.”

“Her prognosis remains unclear but, at a minimum, we expect a long recovery,” they said in a statement, renewing a call for Tennessee Governor Bill Lee to commute Pike’s sentence to life in prison.

Pike’s legal team is seeking a court order requiring the Tennessee Department of Correction to preserve all “relevant physical, written and electronic evidence” related to the failed execution, court documents said. A hearing is scheduled for Wednesday.

Pike’s failed execution revived the debate about capital punishment in the United States.

Lee suspended executions in Tennessee pending an independent investigation and the state’s prison chief announced his resignation.

Laura Porter, executive director of the US Campaign to End the Death Penalty, welcomed the third-party probe and the resignation but said “this has occurred before and the state did not follow the recommendations made.”

“It is essential that the execution process no longer be shrouded in secrecy,” Porter said.

There have been no executions in the United States since the incident.

The execution of Jamaal Howard, a man convicted of killing a store clerk during a robbery, is scheduled on Wednesday in Texas.

His lawyers have sought to have his death sentence overturned, citing Pike’s failed execution, but their appeals have been rejected by the courts.

- First to survive -

Joel Zivot, an anesthesiologist and intensive care physician retained by Pike’s lawyers as a medical expert ahead of her execution, speculated in an article in The New York Times about what might have gone wrong.

Zivot said Pike has small veins that would have made it more difficult to insert an IV line to administer the pentobarbital, a sedative that suppresses respiration.

According to Pike’s lawyers, her arms turned purple during the execution and she reported a burning sensation, indications, Zivot said, that some of the pentobarbital had entered the tissue of her arms and not her bloodstream because of a failure of the IV lines.

The pentobarbital used for her execution also may have been degraded, he said, although Tennessee authorities have not released any information about its origin or preparation.

The Death Penalty Information Center, which publishes data and analysis on capital punishment in the United States, said Pike was the first inmate to survive “after being injected with lethal doses of execution drugs.”

Pike was 18 when she and her boyfriend beat and killed 19-year-old Colleen Slemmer at a job training camp in 1995.

The killing gained national attention after Slemmer’s body was found with a pentagram, often seen as a satanic symbol, carved in her chest.

Pike’s lawyers sought clemency citing her age, childhood sexual abuse and mental health problems, including post-traumatic stress disorder.

The case attracted attention in the lead-up to the execution date because Pike would have been the first woman put to death by the state of Tennessee in more than 200 years, according to the Death Penalty Information Center.

Excluding Pike’s failed execution, there have been 29 executions in the United States this year, which have all been carried out by lethal injection.

The death penalty has been abolished in 23 of the 50 US states, while three others – California, Oregon and Pennsylvania – have moratoriums in place.

The Pentagon said on Monday that President Donald Trump had approved the execution by firing squad of Nidal Hasan, a US Army psychiatrist who shot dead 13 people and wounded more than two dozen at a military base in 2009.

Hasan’s execution for the attack at Fort Hood in Texas would be the first carried out by the US military since 1961.