MJ Dr. Murray Trial: Truth about Propofol.

Michael Jackson murder trial has captivated many audiences around the world. I hear about it everyday, on the radio, TV, and at work. What Dr. Murray did, of course, is looked down upon in all health profession. A cardiologist not trained in sedation/anesthesia providing propofol sedation as a sleep aid. Everything about it, was wrong. No monitoring equipment, no ACLS(advance cardiac life support) equipment, no oxygen, no personnel in the room, and lastly no understanding of the drugs being used. Is this malpractice or criminal negligence? That’s up to the jury to decide. Just a note though, Schwarzenegger went out of his way to deny a parole granted (parole committee already granted parole) to a 61 year old dentist who served 25 years of his life sentence for negligently killing 3 patients with anesthesia, and also halved a sentence on a kid who committed a violent crime. That’s our justice in California.

Dr. Conrad Murray

Propofol in its various form

So let’s talk about Propofol. Hot topic! I have notice there are a lot of misinformation about the drug. I heard on the radio Dr. Drew calling it a barbiturate, and everybody saying how short acting it is. It is not a barbiturate, and depends on the circumstances it could be a very long acting drug. It is the safest anesthesia drug in the right hands, in my opinion. Extremely hard to abuse, which almost always requires a 2nd person to help (I’m sure a trained anesthesiologist can do it himself). Here is the except from the package insert:

DIPRIVAN Injectable Emulsion is an intravenous sedative-hypnotic agent for use in the induction and maintenance of anesthesia or sedation. Intravenous injection of a therapeutic dose of propofol produces hypnosis rapidly with minimal excitation, usually within 40 seconds from the start of an injection (the time for one arm-brain circulation).

Before you can understand more what this one arm-brain circulation mumble-jumble, let me give you a quick pharmacology lecture. When you give an IV(intravenous) drug, the drug travels in a specific pattern throughout the body. Your body’s circulation has areas where there are more blood traveling there. We called that “vessel rich tissue”, and that is where the drug goes first. These area include the brain, heart, lungs, kidney, liver and some other organs. But we are most interested in the brain. A certain blood concentration of the drug is required to achieve the anesthesia. With IV administration, good thing the brain is a vessel rich tissue, so the drug effect is pretty fast and you’ll notice the anesthesia effects. Propofol is very lipophilic, so it crosses the blood-brain barrier very efficiently and is fairly potent because of that. Over time, the circulation will “Redistribute” the drug to the rest of the body, which will lower the drug concentration in the brain and the anesthesia effect will start to subside. Propofol being very lipophilic, after it has redistributed it likes to sit in the fat. So you can call this a “third” compartment, where the propofol gets removed from the blood and sit in the fat while it awaits liver metabolism and kidney excretion. Below is a visual of how the drug travels and its effect.

The two compartment model, taken from www.rxkinetics.com

Typically it takes about 23-50mL/kg/min which translate to a few hours for propofol to get eliminated from the body, mainly because it likes to sit in fat and not hit the liver very often. So someone who just had anesthesia the day before does not really need to worry too much about it and can go about their business the next day. However, it is a different story when propofol is infused for a very long period of time. It is typically used in the ICU(intensive care unit) for patients who requires long term sedation to help with healing, and/or they are intubated for safety. If you continue to infuse propofol for long periods of time, the “third” compartment will fill up and the equilibrium of the drug concentration of the full body will rise, and eventually reach a drug concentration to achieve anesthesia in the brain. It has been documented many times describing this effect. Since the fat is filled, the effect of the propofol will last till the liver can metabolize the drug till the decreases the blood concentration to an awake level. Below is extracted graph from the package insert of Diprivan(brand name).

Blood Concentration of Propofol throughout time.

As you can see the 10 day continuous infusion, the blood levels hover very close to anesthesia level. Whenever the plasma propofol concentration is about that “awakening” dotted line means the patient should be asleep. For Michael Jackson’s case, he has been infused with propofol for over months for 8 hours a day! He would be in this exact situation. Dr. Murray made a statement he gave 25mg of the drug. He probably gave more…, BUT with this profile, 25mg can be enough to keep Michael asleep for a while. We know Dr. Murray had purchased gallons of propofol, there must be a way to force him to produce the remainder of the purchase, and then we can tell for sure Michael has been infused for a long long time. This will explain the high blood levels of propofol found in Michael Jackson post-mortem. It may not be enough to cause respiratory depression to a point where Michael Jackson stops breathing, but the number one cause of respiratory failure in anesthesia is obstruction. Without anybody in the room and zero monitors, nobody knows how his death really happened. Some people say he got up and pushed more propofol, and the defense ridiculous claim of ingesting propofol that was hidden in the juice box next to Michael Jackson. Whatever the trigger that caused his death shouldn’t even matter because the daily infusion of propofol, and no careful monitoring is what really killed him.

Here is my personal opinion about the case. Dr. Murray has definitely showed criminal negligence in not monitoring, and also not understanding the pharmacology behind propofol. If a dentist can be criminally charged for using inappropriate anesthesia, I don’t see why he should fall under the same charges. All propofol use should be used with a monitor can that watch blood O2 saturations, ECG, blood pressure, some form of breathing confirmation(CO2 monitoring, or pre-cordial stethescope), a personnel trained in airway management in the room at all times, and ACLS equipment to manage an airway/respiratory crisis. Four years may not be worth the tax money? I think the criminal charge to forcibly remove his license to practice medicine is more important than the punishment. We do not need a physician out there practicing dangerous medicine.

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