Two of the three drugs used in lethal injection are not administered in a way that reliably produces painless death for inmates, leaving at least some to die of suffocation and be conscious enough to realize it, according to a new analysis of executions in California and North Carolina.
Reviewing the cases of 41 inmates dating back to 1984, the researchers found that the dose of anesthesia given at the start of an execution varied widely and was often insufficient to keep an inmate unconscious.
They also concluded that the chemical intended to induce cardiac arrest did not always stop prisoners' hearts.
"The argument that's always been given about lethal injection is that in theory, a well-trained person could give it humanely," said Fordham University law professor Deborah Denno, who has studied lethal injection for 15 years and is a death penalty opponent. "This casts doubt on even that."
The study, published today in the Public Library of Science journal PLoS Medicine, provides scientific data for a debate that has largely lacked hard evidence regarding the medical underpinnings of lethal injection.
California and 11 other states have put executions on hold, mostly because of concerns over the constitutionality of lethal injection. Gov. Arnold Schwarzenegger and state Atty. Gen. Jerry Brown intend to recommend reforms by May 15.
The study is "shedding light on a process that should have been examined a long time ago," said Michael Rushford, president of the Criminal Justice Legal Foundation, a Sacramento advocacy group that favors the death penalty.
Though he doubted many of the study's conclusions, he thought lethal injection might be too problematic to preserve. "The real issue should be 'Is this the best way to do this?' Let's get some doctors together and say, 'If you were going to put your mother down, how would you do it?' "
Execution by lethal injection was devised in 1977, after an Oklahoma state legislator who opposed capital punishment worked with the state medical examiner to seek a more humane alternative to electric chairs and firing squads.
They developed a regimen of three powerful drugs: the sedative sodium thiopental, to make the inmate unconscious; the muscle relaxant pancuronium bromide, to induce paralysis; and potassium chloride, to stop the heart.
Each was supposed to induce death on its own; the combination intentionally redundant. The regimen was never scientifically tested, but it was widely adopted by other states and was used first in 1982 in Texas.
More than 30 states allow the death penalty; of them, all but one offer lethal injection, and most use the three-drug regimen.
But acceptance of lethal injection as a humane method of execution has been waning. Inmates filed suit, arguing that it violated the constitution's prohibition against cruel and unusual punishment.
U.S. District Judge Jeremy Fogel in San Jose put all California executions on hold last year after a challenge from San Quentin death-row inmate Michael Morales.
As of Monday, 901 inmates had been executed by lethal injection in the United States, according to the Death Penalty Information Center, a Washington group that opposes capital punishment. Ohio is scheduled to execute James Filiaggi this morning.
The new study focused on executions in California and North Carolina because those states had the most complete information available.
The authors included an anesthesiologist, a pharmacologist, a molecular biologist, a veterinarian, an attorney and a historian. Many have described themselves as death penalty opponents.
Several of the researchers worked on a 2005 study that found prisons routinely failed to administer enough anesthesia to keep inmates unconscious throughout their executions. They based their conclusions on the concentration of anesthesia measured in the bloodstream at post-execution autopsies.
In the new study, the researchers focused on what they believed was a key problem: that inmates were given uniform amounts of anesthesia regardless of their body weight or other factors, such as their tolerance for barbiturates. North Carolina uses 3 grams of thiopental; California requires 5 grams.
Because North Carolina records included the weight of each inmate, the researchers were able to calculate the dosages in that state, which ranged from 10 to 45 milligrams per kilogram.
They calculated that states such as Virginia that use 2 grams of thiopental were administering doses between 6.6 and 30 milligrams per kilogram.
Those dosages are below what is necessary to have a 50-50 chance of euthanizing many laboratory animals such as rabbits, dogs and rats, according to the study.
In some cases, the dosage overlapped with the 3-to-6.6-mg-per-kg dose of thiopental used to anesthetize patients at the outset of a surgical procedure. But in an operation, more anesthesia would be administered throughout the procedure to keep the patient under.