Executed in U.S. may be awake as they suffocate

By Jane Sutton

MIAMI (Reuters) - Some prisoners executed by lethal injection in the United States may die of suffocation while they are still conscious and in pain, University of Miami researchers said on Monday in a study that concluded the drugs do not work as intended.

The study, published in the Public Library of Science journal PLoS Medicine, raised new questions about whether the lethal cocktail violates the U.S. constitutional ban on cruel and unusual punishment.

Lethal injection is the primary method of execution for 37 U.S. states and the federal government, though more than a dozen states have halted or suspended the procedure because of legal or ethical questions.

The drugs used are the anesthetic thiopental, pancuronium bromide to paralyze the muscles and lungs, and the electrolyte potassium chloride to stop the heart.

First adopted by Oklahoma lawmakers looking for a humane alternative to the electric chair, the combination is supposed to produce unconsciousness and then death due to respiratory and cardiac arrest.

The researchers studied drug dosages and time elapsed until death in 42 lethal injections in North Carolina and eight in California.

They concluded the thiopental might have been insufficient to keep the prisoners unconscious in some cases, based on concentrations in their blood after death.

They said the potassium chloride injection, which causes an intense burning sensation, did not reliably hasten death because prisoners given it died no faster than those who got only the other two drugs.