There’s no mystery about why the July 23 execution of Joseph Wood in Arizona took so long. From the anesthesiologist’s point of view, it doesn’t seem surprising that the combination of drugs used—midazolam and hydromorphone—might take nearly two hours to cause death.
Here’s why.
The convicted murderer didn’t receive one component of the usual mixture of drugs used in lethal injection: a muscle relaxant. The traditional cocktail includes a drug such as pancuronium or vecuronium, which paralyzes muscles and stops breathing. After anyone receives a large dose of one of these powerful muscle relaxants, it’s impossible to breathe at all. Death follows within minutes.
But for whatever reason, the Arizona authorities decided not to use a muscle-relaxant drug in Mr. Wood’s case. They used only drugs that produce sedation and depress breathing. Given enough of these medications, death will come in due time. But in the interim, the urge to breathe is a powerful and primitive reflex.
So-called “agonal” breathing, which precedes death, may go on for minutes to hours. The gasping or snoring that eyewitnesses described would be very typical. People who are unconscious after overdoses of heroin try to breathe in a similarly slow, ineffective way, before they finally stop breathing altogether or are rescued by emergency crews.
More about the drugs
Midazolam is a member of a class of drugs called benzodiazepines. The common “benzos” that many people take include Valium, Xanax, and Ativan. What these drugs have in common is that they produce relaxation and sleep. You might take a Xanax pill, for instance, to help you nap during a long flight.
In anesthesiology, we use benzodiazepines for another important reason: because they produce amnesia. There are stories of people taking a Valium to relax a little before they give an important talk, and the next day panicking because they can’t remember if they actually showed up and gave the talk.
Amnesia can be very helpful in my business. Many of my patients don’t want to remember coming into the operating room and seeing the bright lights and surgical instruments. After I inject one or two milligrams of midazolam into the IV, they’re often smiling and relaxed, and they have no memory later of coming into the operating room at all. The next thing they know, surgery is over and they’re waking up.
