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Logo of bmjThis ArticleThe BMJ
BMJ. 2007 May 5; 334(7600): 920.
PMCID: PMC1865446

Some executed US prisoners may have suffocated

Condemned prisoners who are killed by lethal injection may often suffocate while still conscious and be aware of what is happening to them, shows a new analysis of data on US executions. The analysis provides new evidence that the punishment may be cruel and unusual and thus unconstitutional.

This is likely to be what occurred in the botched 2006 execution of Angel Diaz, write Teresa Zimmers of the University of Miami Miller School of Medicine and colleagues (PLoS Medicine 2007;4:e156).

Mr Diaz, who took 34 minutes to die while wincing, shuddering, and gasping for air, was later found to have 30 cm burns on both antecubital fossae. Florida's medical examiner concluded that the drugs had been delivered subcutaneously rather than intravenously.

“The conventional view of lethal injection leading to an invariably peaceful and painless death is questionable,” Dr Zimmers and her team conclude.

About a dozen of the 37 states that impose the death penalty have suspended executions because of concerns about the constitutionality of lethal injection. The new study is likely to be used in legal challenges to the practice, said Bryan Liang, executive director of California Western School of Law's Institute of Health Law Studies. Although the study is not the “final word” on whether lethal injection is cruel and unusual, he said, the researchers “did a lot with what they had and they were thorough.”

The researchers analysed data on drug protocols, time to death, dosages by body weight, witness testimony, and other available information in the cases of 33 executions carried out by lethal injection in North Carolina and nine in California.

The execution protocol typically includes a short acting barbiturate such as thiopental sodium to act as an anaesthetic and to induce respiratory arrest, pancuronium bromide to cause paralysis, and potassium chloride to stop the heart.

“There literally are thousands of articles on each of these medications,” said Leonidas Koniaris of the University of Miami, a co-author of the study. “To administer all three properly, recognising that one precipitates the other, is extremely complicated.”

In a 2005 study (Lancet 2005;365:1412-4), Dr Koniaris and colleagues reported that prison personnel responsible for executions had no training in anaesthesia and that drugs were delivered remotely with no monitoring, recording of data, or peer review. The researchers in the current study wrote that their analysis of the amount of thiopental sodium used in various protocols showed that some of those who were executed received “near the upper range of that recommended for clinical induction of anesthesia . . . clearly not a dose designed to be fatal.”

They point out that some inmates were still breathing up to nine minutes after the drug was administered. Potassium chloride itself may not always kill, they note, given that when the drug was added to North Carolina's thiopental and pancuronium protocol the times to death did not change.

They say that it is likely that, in some cases, “death by suffocation would occur in a paralyzed inmate fully aware of the progressive suffocation and potassium-induced sensation of burning.”

Dr Liang said that to be unconstitutional under US law a punishment must be both “cruel and unusual”—not just one or the other. The inconsistency in administration found in the current study provides strong evidence that lethal injection is “unusual,” he added, in that every executed individual is not treated the same way.

“People are realising that although it may look nice and clean, it is not a nice and clean activity,” he said.

Articles from The BMJ are provided here courtesy of BMJ Publishing Group