Christa Pike, 50, remains unconscious and on a ventilator at a Tennessee hospital four days after the state failed to execute her, according to one of her attorneys, who said Sunday that her prognosis may not be known for several more days.

Pike has remained hospitalized under guard since Wednesday night, when Tennessee prison officials administered two doses of the lethal-injection drug pentobarbital. The drugs failed to kill her, and her attorneys have said the injections left her arms burned and blistered.

Assistant Federal Defender Stephen Ferrell, who represents Pike, said during an appearance on CNN's State of the Union that he was not aware of Pike regaining consciousness following the execution attempt.

Pike has given another person medical power of attorney, and that individual is handling decisions about her care while protecting her privacy. Her defense team has not identified that person or disclosed additional details about Pike's condition.

Ferrell said doctors may need several more days before they can determine whether Pike will recover and whether she suffered lasting physical or mental harm during the failed execution.

Pike's execution was delayed for more than eight hours Wednesday while the Supreme Court considered an appeals court ruling that had temporarily blocked the lethal injection. The appeals court had sought additional review of whether jurors who sentenced Pike to death should have considered allegations that she was sexually abused as a child. The Supreme Court ultimately allowed Tennessee to proceed.

Following the failed execution, Pike's attorneys asked a court Friday to require Tennessee officials to preserve written records, communications, photographs and video related to the procedure. Ferrell has also criticized the state's secrecy surrounding its execution protocols, including information about lethal-injection drugs and their testing.

The incident has renewed scrutiny of Tennessee's capital punishment system. It was the second time this year that Tennessee failed to complete an execution after a prisoner had been taken to the execution chamber. In May, officials halted the execution of Tony Carruthers after staff were unable to establish a secondary IV line.

Tennessee Department of Correction Commissioner Frank Strada announced Saturday that he was resigning. Gov. Bill Lee has ordered an independent investigation of the state's capital punishment system led by former U.S. Attorney Ed Stanton.

Pike's attorneys have also asked Lee to commute her death sentence to life imprisonment. If she survives, her lawyers say questions could remain about the extent of her recovery and whether she is mentally competent.

Pike was 18 when she and her boyfriend, Tadaryl Shipp, killed 19-year-old Colleen Slemmer in 1995. The two were classmates at Knoxville Job Corps.

Prosecutors said Pike believed Slemmer was a romantic rival and lured her to a secluded area, where Pike and Shipp attacked Slemmer with a box cutter and a large piece of asphalt. Slemmer was tortured and beaten before being killed, and a satanic symbol was carved into her body.

Pike did not deny killing Slemmer. Shipp is serving a life sentence in prison.