BATON ROUGE - A federal judge hearing a challenge to Louisiana's death row protocols was in a quandary Friday: How can the state kill Jessie Hoffman without evoking childhood trauma, interfere with his Buddhist breathing exercises or make him relive an armed robbery?

To Jessie Hoffman's lawyers, Louisiana can't execute him by nitrogen hypoxia without violating his rights under the Constitution. The state says the asphyxiation would be quick and relatively painless, and that he must pay for his crimes.

U.S. District Judge Shelly Dick is letting Hoffman proceed with his claim that asphyxiation with nitrogen gas is less humane than other methods the state of Louisiana can use. He has suggested the use of a firing squad, but lawyers for the state say if there are worries about triggering trauma: wouldn't training a gun on him remind him of when he was a robbery victim?

The inmate has also proposed the use of a drug mixture similar to those used in assisted suicides. Louisiana has said those drugs aren't available to put people to death.

After testimony concludes Friday, Dick is giving each side 12 hours to prepare written arguments. A decision could come by the end of the weekend, and what she decides will likely be appealed.

Hoffman is scheduled for execution March 18 in the Louisiana State Penitentiary at Angola. Louisiana adopted its execution plan just last month. Hoffman would be the first to be put to death under it.

Hoffman kidnapped, raped and murdered a New Orleans advertising account executive in 1996, leaving her body in a wilderness area near the Pearl River in eastern St. Tammany Parish. Mary "Molly" Elliot was 28 when she died.

Lawyers for the state says a 1912 court ruling lets the state decide how to put inmates to death. The judge hearing Hoffman's challenge to Louisiana's death penalty protocol said a change can be made as long as the new method isn't potentially worse.

The inmate, the judge said, has "sufficiently alleged nitrogen hypoxia is less humane than other methods."

Hoffman cited documents from the United Nations and veterinary groups saying hypoxia is potentially torturous and inhumane. Louisiana law has banned hypoxia-based euthanasia for cats and dogs for more than a decade.

"The process of gassing is so gruesome," said Dr. Lee Capone, a veterinarian who testified by video on Hoffman's behalf. He saw dogs euthanized with carbon monoxide in 1983 and led an effort to stop the practice.

"It was pretty horrific to see it," he said.

Louisiana says Hoffman would become unconscious after breathing pure nitrogen for 40 seconds or so, maybe quicker. One lawyer in Friday's hearing suggested while interviewing a witness that if Hoffman practiced deep breathing as the nitrogen flowed, he would die more quickly.

Throughout the day, doctors discussed how quickly inmates would become unconscious or die under the alternate methods: 3-5 seconds for a firing squad and more than 5.5 minutes for the drug mix.

Hoffman sat in the courtroom during the testimony, looking straight ahead.

The state began acquiring nitrogen gas for the execution last July; a state prison official testified Friday that the gas on-hand was more pure than medical-grade, but had not been tested.

The U.S. Constitution bars cruel and unusual punishment, and Hoffman's lawyers fear that asphyxiating Hoffman goes too far. As a Buddhist, they say, he performs meditative breathing exercises and that using a facemask to force him to breathe a gas that will kill him is cruel.

Alabama has killed four inmates using nitrogen gas. Witnesses said those executions have taken longer than lethal injections. Lethal injections, however, are difficult to carry out because pharmaceutical companies will not provide drugs for executions.

Louisiana lawmakers adopted nitrogen hypoxia as a method of execution last year. Gov. Jeff Landry announced last month that new protocols were ready, and lawyers for the state and Hoffman released them Thursday in advance of Friday's hearing.

The state had wanted them kept under wraps while Hoffman's lawyers wanted them in the open. A redacted version was made available.

Dick must decide whether Hoffman can be killed in a manner that preserves his constitutional rights while also considering Louisiana's quest for justice. State lawyers have said victims' families have the right to see their loved ones' killers put to death under the law. The state Corrections secretary said two family members would be among seven witnesses.

An additional execution had been set for March 17, but Christopher Sepulvado died at age 81 after his death date was set. He was convicted of killing his stepson three days after marrying the boy's mother.