Christa Pike execution: A picture taken on December 4, 2007 shows death row inmate Christa Pike entering a Knox County Criminal Court in Knoxville, Tennessee, US. (Source: Reuters)Christa Pike, who was sentenced to death in the US state of Tennessee, is critically ill, unconscious and put on ventilator after failed attempts to execute her using lethal injection, according to court filings by her lawyers.Pike, 50, was unconscious, intubated and receiving treatment at a hospital in the Nashville area after surviving an attempted execution, despite giving her two doses of pentobarbital.Her lawyers have called the execution attempt botched and are seeking to preserve evidence from it while asking authorities to reduce her death sentence.Several attempts to insert the IV lineAccording to the latest court filing, prison officials used at least seven needles to try to insert an IV line before giving Pike the lethal drug.One needle was reportedly bent at a 90-degree angle when it was removed. At one point, Pike herself told the execution team where they could try to establish an IV line, her lawyers said.Pike was then given two doses of pentobarbital. Her lawyers said she could be heard crying, whimpering and breathing heavily during the procedure.She was then taken by ambulance to hospital, where medical staff have been treating her and working to clear the lethal drug from her system.Story continues below this adPike’s lawyers said in the filing that members of the execution team did not realise that the IV lines may have been improperly placed or that her veins had ruptured, according to a BBC report.Dr Joel Zivot, an anaesthesiologist advising Pike’s defence team, said the two doses would ordinarily have been sufficient to cause death if the drug had entered her bloodstream normally.He suggested that the drug may instead have spread into tissue beneath her skin after a vein ruptured. Blisters reportedly appeared on Pike’s arm following the procedure.Zivot also said Pike’s thrombocytosis, a condition related to abnormal blood clotting, could have contributed by causing clots at the injection site and interfering with the drug entering her veins.Story continues below this adHe also raised the possibility that the pentobarbital (the lethal drug) could have been degraded because of issues such as manufacturing or storage, although authorities have not said that this has happened.What is the stage of this caseTennessee Governor Bill Lee has ordered an independent review of the failed execution and halted executions in the state for the remainder of the year.The state’s Department of Correction has defended the procedure, saying its protocol did not permit additional procedures beyond those carried out.Authorities have not confirmed yet whether they would attempt to execute Pike again or explained what caused the failure.Story continues below this adPike’s lawyers filed an emergency motion on Friday seeking to preserve any and all evidence connected to the execution attempt, including physical, written and electronic records, according to BBC.About Pike’s casePike was sentenced to death for the 1995 murder of 19-year-old Colleen Slemmer in Knoxville, Tennessee in 1996. Pike was 18 at the time.She and 2 other beat and tortured Slemmer before killing her, according to the case record. Pike was sentenced to death after that.Shipp was 17 when the killing took place and was therefore not eligible for the death penalty under state law. He received a life sentence with the possibility of parole and remains in prison.Story continues below this adPike, the only woman on Tennessee’s death row, had made several last-minute legal attempts to stop her execution. The US Supreme Court rejected two efforts, while Governor Lee denied her request for mercy.