In the spirit of Halloween, I will be posting a few ghoulish things on the blog over the next few weeks.  So why not talk about the best way to kill someone and have it be a good study on A&P and pharmacology to boot?

I was reading this article about lethal injection and was reminded that I often used to teach my students some basic A&P using lethal injection as an example of cellular osmosis and diffusion problems.  In looking at this method of lethal injection from the perspective of someone who has used these drugs and teaches A&P, it seems that the prisoners rightly have something to worry about.

GABA Receptor

So, how do these drugs really work you may ask?  Well, let’s take them one at a time.  Valium is a benzodiazepine.  It stimulates GABA receptors in the brain which cause the propagation of nervous signals to become more difficult in that organ.  “Huh?” you may ask.  There are many types of proteins that are embedded into the cell membrane of cells all over our body.  These are meant to react to outside chemicals and to trigger changes within the cell.  GABA receptors are one such protein which are existent in much of the nervous system including the brain.  Stimulation of a GABA receptor causes the membrane to become less responsive to electrical stimulation.  Since brain activity relies on electrical stimulation, your brain function will be slightly impeded.  This causes sedation and euphoria which help patients get through painful procedures.  This drug does not prevent the patient from feeling any pain.  It will, however, make the patient care less about that pain.  The GABA receptor is an interesting little protein that actually has what could be called spokes that protrude out from the membrane.  There are five such spokes and benzodiazepines only act on one of them.  Another drug later in the procedure will be used to stimulate another spoke of that same receptor.  The prisoner is given valium first in order to take the edge off and reduce anxiety.  This is actually common before surgery. 

The second drug that is given is not listed in the Leo article, but I did find it on this page.  Sodium thiopental is a potent barbiturate which produces its effects by stimulating a spoke on the GABA receptor other than the benzodiazepine listed above.  This stimulation of GABA receptors is much more potent and the patient goes beyond a reduction of anxiety and into a deep sleep.  I have never used this drug in the past and I have no personal experience watching its effects on people.  However, I do know that this is a very old drug that was developed in the 1930’s and is rarely used today.  Versed and propofol are more common choices for anesthetic procedures such as surgery.  Even though this would be effective, one wonders why newer and more reliable drugs are not being used.

The next drug of choice is the one that confuses me.  Pancuronium is next administered to the patient in order to induce paralysis.  Neuromuscular blocking agents such as pancuronium have a rich history that starts with poison darts used by native peoples in South America.  The original substance found on these darts was curare which is extracted from a few South American woody plants.  Pancuronium is a derivative of that chemical and is in use today for surgery.  The drug works by binding to the receptor sites that normally cause muscle cells to contract.  Pancuronium binds to these sites without causing muscle contraction, and they stay bound to the site for quite a long period of time.  Since the receptors that cause muscle contraction are bound by this tenacious chemical, no other muscle contractions can occur.  This causes paralysis of nearly all the skeletal muscles in the body including the muscles responsible for respiration.  After the administration of this drug the patient will no longer be able to breathe.  However, this drug causes no sedation whatsoever.  The patient can still think and perceive pain and the heart will continue to beat.

Why is pancuronium confusing to me?  Well, it is unnecessary when you look at the last drug that will be pushed.  More on that in a minute.  But for now the reader should be aware that the patient will be completely paralyzed and unable to communicate.  The patient will also be unable to breathe.  So if the patient is feeling any pain, he or she will not be able to communicate that complaint.  The reader may ask, “But isn’t this how surgery is done?  If it is possible to use these drugs to perform surgery on a patient, surely this must be enough sedation to make the prisoner comfortable during death?”  Before one makes that argument, one has to remember that I have previously stated that sodium thiopental is an older choice of drug.  There are more up to date and better choices available.  If versed or propofol were being used, this would be less of an issue.

But the big gorilla in the room is the last drug given which is potassium chloride.  Believe it or not this drug is a simple salt solution.  You would not want to put this on your food, but it is similar and is used to de-ice roads.  Potassium chloride when used appropriately will provide complete and instant death due to a simple trick of diffusion.  Every single cell in your body has a function.  In order to perform this function, the cell must be stimulated by some mechanism, and the cell must use energy in the form of an electrical discharge.  As a cell in the body electrically discharges two things must happen.  The sodium outside the cell must be allowed to cross the cell membrane to enter the cell.  And the potassium contained inside must be allowed to cross the cell membrane to exit the cell.  This electrolyte swap is the basis of all cellular activity.  This will take place with all the cells in your heart, lungs, and brain.  In other words, if you interrupt this process, the patient will be unable to think, breathe, or perfuse blood.

Why does administering salt water disrupt all these processes?  The answer is simple diffusion.  In order for an electrolyte to cross a cell membrane all on its lonesome, there must be a reduced amount of that same electrolyte on the other side of the membrane.  Otherwise there will be no physical attraction for that electrolyte to travel.  By administering a large dose of potassium chloride, the executioner is creating a chemical environment which physically prevents muscle contraction and nerve signal propagation.  In other words, instant death.  Pushing simple salt water into the patients veins instantly prevents them from feeling pain, thinking, breathing…you name it…its prevented.  Potassium chloride is basically instant chemical death in a vial.  Knowing this, one may wonder why all these other drugs lead up to the administration of this one.  Why not just push it first and be done with it?

There would obviously be a lot of anxiety in someone who was about to be executed.  So an initial dose of a benzodiazepine makes sense.  This would take the edge off and facilitate other procedures going smoothly.  The second dose of anesthetic also makes sense.  Placing the prisoner into a deep coma before death also seems humane.  Although, as I have said previously, I might be inclined to chose another more modern agent for that purpose.  The last drug that completely and irrevocably kills the prisoner is also desirable since that is what you are there to do. But why use the paralytic?  Is it overkill?  Possibly.  The drug you are going to push right after it will cause the same effect in another, more reliable fashion.

It is this added step that people seemed concerned about.  The administration of pancuronium will start to suffocate the patient which is not instant death.  If the older anesthetic used for the procedure somehow did not provide enough sedation the prisoner would be laying there suffocating.  This condition would persist while the last drug is being prepared.  In the final analysis, the administration of a neuromuscular blocking agent is both unnecessary and may complicate the procedure.

I have seen two animals euthanized with potassium chloride.  On one occasion it was the only drug that was given to the animal.  Let me tell you, I have been a paramedic for many years and I have never seen anything die that fast.  The cat instantly fell limp to the table before the complete contents of the syringe could be pushed over the course of one or two seconds.  If that is what is in store for the prisoner immediately following paralysis, why do we not just skip ahead to the big guns without further complicating things?

How would I do it?  Please keep in mind that I am not an anesthetist.  Nor am I an experienced executioner.  Far from it.  But I have used many of these drugs with ventilator patients in the course of my duties as a critical care paramedic.  So I might do something like the following:

1. Administer an oral benzodiazepine such as valium or versed to take the edge off.
2. Get the prisoner to the table, start an IV and give an incredibly large amount of a modern anesthetic such as versed or propofol.  Propofol needs a pump, so I would be more likely to give something like 20mg of versed which is 2 to 4 times the absolute maximum dose that any human should receive at any given time.  By this time the prisoner would be completely comatose.  However, if something had gone wrong with the procedure (such as IV effusion) I would still be able to assess the consciousness of the patient and act appropriately.  By the way, versed can be administered outside of an IV so even if something should go wrong with the IV, the drug will still provide a high level of sedation until another IV is established.
3. Pump a ridiculous amount of potassium chloride into the line.  Let’s just get this done.
4. Look at your ECG for asystole, listen to heart tones with a stethoscope, and confirm death.

And there you have it, a perfectly humane death cocktail from yours truly just in time for Halloween.  Kids, don’t try this at home.  Executioners?  Please do give this a try.  And remember, try to kill people responsibly.

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