The authors believe the use of lethal injection should stop in order to prevent unnecessary cruelty and call for a public review into anaesthesia procedures during executions.

Lethal injection is the most common way people are legally put to death in the USA as there is a perception that the process is relatively humane and does not violate the US Constitution’€™s Eight Amendment prohibiting cruel and unusual punishment.

Anaesthesia during lethal injection is essential to minimize suffering and preserve public opinion that lethal injection is a near-painless death.

Lethal injection generally consists of the sequential administration of sodium thiopental for anaesthesia, pancuronium bromide to induce paralysis, and finally potassium chloride to stop the heart and cause death. Without anaesthesia the person would experience suffocation and excruciating pain without being able to move.

Leonidas Koniaris of the University of Miami’€™s School of Medicine and colleagues analysed protocol information from the states of Texas and Virginia, where around 45% of executions are done.

They found that executioners had no training in anaesthesia, drugs were administered remotely with no monitoring of anaesthesia and there were no data collection, documentation of anaesthesia, or post-procedure peer review. They also noted that neither state had a record of the creation of its protocol.

The investigators also analysed data from autopsy toxicology reports from 49 executions in Arizona, Georgia, North Carolina, and South Carolina.

They found that concentrations of thiopental in the blood were lower than that required for surgery in 43 of the 49 executions; 21 inmates had concentrations consistent with awareness.

The study suggests that the current practice of lethal injection for execution fails to even meet veterinary standards for putting down animals.

‘€œOur data suggest that anaesthesia methods in lethal injection in the US are flawed,’€ Dr Koniaris states. ‘€œFailures in protocol design, implementation, monitoring and review might have led to unnecessary suffering of at least some of those executed.

‘€œBecause participation of doctors in protocol design or execution is ethically prohibited, adequate anaesthesia cannot be certain. Therefore to prevent unnecessary cruelty and suffering, cessation and public review of lethal injection is warranted.’€

In an accompanying editorial, The Lancet comments: ‘€œWhether you receive the death penalty depends not on what you have done, but where you committed your crime, what colour your skin is, and how much money you have.

‘€œThe use of the death penalty not only varies from state to state (12 US states have no death penalty) but from jurisdiction to jurisdiction within a state. Repeated studies have shown a pattern of racial discrimination in the administration of the death penalty.

‘€œCapital punishment is not only an atrocity, but also a stain on the record of the world’€™s most powerful democracy. Doctors should not be in the job of killing.

‘€œThose who do participate in this barbaric act are shameful examples of how a profession has allowed its values to be corrupted by state violence.’€