References
Primary:
Department of Justice Pamphlet: Positional Asphyxia - Sudden Death
Secondary:
Minnesota Model Policy For Use Of Force
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Overview
There are three theories as to how George Floyd died.
The Overdose Theory
As mentioned previously, it's not easy to clobber the respiratory drive using alcohol, because when you keep missing your mouth, it's hard to drink more. With Fentanyl, it's much more convenient to get a deadly overdose on board.
George Floyd may have taken a whole handful of pills, just before Thomas Lane rapped on his window. Seeing the police approaching, Floyd concealed his illicit stash by ingesting it.
There are a couple of problems with this idea. For one thing, destruction of evidence means consciousness of guilt, and George Floyd doesn't seem to have been conscious of guilt. If he worried the cops might be looking for him, why didn't Floyd just leave? If he wanted to get his stash out of sight, why not just put it in Morries's travel bag with the other drugs? And if he really did see the police coming and his first thought was to swallow the goods, why did he seem so surprised when he first saw Thomas Lane? Floyd was pretty scatterbrained, and it's possible he consumed his stash and then forgot what he was doing. But that's a bit of a stretch; the video doesn't really support this version of events.
Be that as it may, Floyd's post-mortem blood concentration of Fentanyl was about 11 ng/mL. Fatalities have been reported at a fraction of that concentration, leading some to claim that Floyd had "three times the fatal dose" of Fentanyl in his bloodstream. This does not take into account the massive individual variation in human opioid tolerance. The lowest-dose fatalities would be seen in opiate-naive organisms, possibly in synergy with alcohol. George Floyd had no alcohol on board, and he was definitely not opiate-naive. His tolerance might be orders of magnitude higher than another person's.
George Floyd was not dead when Thomas Lane found him, so if he had a fatal overdose of Fentanyl inside him at that time, it was in his stomach, not yet absorbed into the bloodstream. Floyd became unresponsive about a quarter-hour after Thomas Lane first contacted him, which should be enough time to absorb a fatal overdose. The effects of Fentanyl are as follows:
Euphoria: a feeling of warmth and happiness; lack of concern for material circumstances; inappropriate laughter
Analgesia: reduced or absent pain sensation
Miosis: constriction of the pupils
Neuromuscular Deficit: swaying, staggering, "weakness", slurred speech
Altered Mental Status: confusion, disorientation
Nausea / Vomiting
Reduced Consciousness / Drowsiness
Unresponsiveness
Absent Cough Reflex
Respiratory Failure
Of course Floyd did not laugh or vomit, but these signs are not seen in every case. As for the other signs, they present in roughly that order as the drug is absorbed. Higher brain functions are affected first, respiration last.
Thomas Lane looked at Floyd's eyes for signs of drug use. He said Floyd exhibited nystagmus, "eyes like shake back and forth really fast". Lane thought this might indicate Floyd was on PCP, a drug in the elephant-tranquilizer class. Nystagmus can happen for many reasons or even no reason (voluntary nystagmus is surprisingly common; I can do it myself). It turned out Floyd was not on PCP. But Lane did look at Floyd's eyes, and Lane did not notice constriction of the pupils. Given the dose of Fentanyl Floyd was on, it's hard to believe his pupils were unaffected. His dark eye color must have made the observation difficult.
As the drug seeped into Floyd's brain, he became uninterested in the officers, withdrawn into his happy self. Pain compliance techniques ceased to affect him. Floyd stumbled and lurched about, voicing inarticulate sounds. His head drooped as drowsiness overtook him, before he collapsed to the pavement. Nothing the officers could do was enough to wake him. His airway gurgled or rattled gently as his breathing became slower and shallower. His lips and mucous membranes took on a bluish tint; he slipped into oblivion.
The officers had no way of knowing any of this, because Floyd never admitted he was on Fentanyl.
The Heart Failure Theory
The medical examiner dissected George Floyd's heart, to see whether Floyd died of a heart attack. The ME found no evidence of heart attack, but he did find "multifocal, severe" coronary artery disease, with some of the main vessels being 75% or even 90% occluded. Floyd's heart was also enlarged: almost 10% heavier than a "normal" heart for a man his size. The ME had access to medical records and he noted Floyd's history of hypertension, which is consistent with these findings of heart disease.
They call hypertension the silent killer because it isn't symptomatic by itself. It can go undetected, undiagnosed, untreated for decades, and the first sign of trouble might be heart failure, kidney failure, or a stroke. Had he lived, Floyd would be at risk for these developments, and the coronary artery disease also put him at risk of angina or heart attack. But at the time of his death, Floyd did not have a history of angina or heart failure. You might suppose that a 90% occlusion means a 90% risk of heart attack or a 90% reduction in cardiac function. The vasculature of the heart is way more sophisticated than that. It can pump with its own muscles and route around damage by adjusting the configuration of the capillary beds. Floyd had severe heart disease, and it would have told on him sooner or later; they say big dogs die young. But he didn't "suffer from" heart disease, and he wasn't at risk for sudden, emergent heart failure.
Heart failure means the heart can't pump enough blood to keep the organism in best health. It is a chronic, degenerative condition with many potential causes. There may be a problem with the heart muscle, the valves, or the electrical control system of the heart. When a person exerts himself, even in a small way such as standing up and walking across the room, the medulla sends a polite request to the heart to beat faster and pump more blood. If the heart can't accommodate the request, the organism may be temporarily overwhelmed and forced to rest. Thus, the main consequence of heart failure is sharply decreased capacity for exertion. Even easy tasks such as making a bed or cooking a meal can be too much. Heart failure patients can't maintain a physical fitness schedule; they are typically flabby and weak.
The other consequence of heart failure is edema: increased pressure and accumulation of fluid in the capillaries and veins. When the right side of the heart fails, you see swelling and discoloration of the feet and maybe the hands. When the left side fails, a liquid called "pink frothy sputum" seeps into the lungs: pulmonary edema. With exceptions too pedantic to mention, both sides of the heart fail at the same time. So now you've got tender extremities, a frail, flabby body, and shortness of breath to go along with decreased capacity for effort.
The most common outward signs of heart failure are oversized comfy slippers, a mobility scooter, and supplemental oxygen. George Floyd did not show these signs; he was not a heart failure patient. But there is at least one medical theory to explain how a person can go from asymptomatic to emergent heart failure in a matter of seconds. The best theory takes into account a tumor the ME found in Floyd's body. Under hormonal stress, this tumor released a lethal dose of catecholamine, a chemical so injurious to health that anyone who can't pronounce it will surely die. This is why Floyd was foaming at the mouth the whole time; his heart had failed and his lungs were overflowing with sputum.
Floyd went into emergent heart failure. His maximum heart output was insufficient to maintain life, even at rest. At first he postured, sitting upright with his shoulders expanded to compensate for his shortness of breath. For a time, the struggle to breathe consumed all of his dwindling physical capacity. But weakness, extreme weakness, soon permeated his frame. Every tissue in his body was famished, not only for oxygen but for sugar and other nutrients. His muscles cramped with accumulated lactic acid. He became disoriented; his awareness flickered; his nerve signals were weak and indistinct. From the crown of his head to the soles of his feet, his body was drenched with glistening extra-slimy sweat as his skin dumped metabolic waste through his pores. He soon collapsed and became unresponsive. Unconscious, his respiratory effort was nowhere near equal to the task of breathing with sodden lungs.
His lips and mucous membranes took on a bluish tint; he slipped into oblivion. The officers had no way of knowing any of this, because they weren't privy to Floyd's medical history.
The Positional Asphyxiation Theory
This theory leans heavily on an advisory pamphlet put out by the National Law Enforcement Technology Center, a sub-sub-subdivision of the DOJ. The title of the pamphlet is Positional Asphyxia - Sudden Death. Positional asphyxia can occur when a suspect is physically positioned in such a way that his chest movement is impaired, causing breathing difficulty.
The pamphlet is written for a general audience. It is not official training material, but it describes essential concepts in which all police are trained. A key concept is that officers have only a limited selection of use-of-force options, none of which is perfect. Every force technique has its limitations and risks. One of the best techniques - the prone restraint position - brings with it the risk of accidental death by positional asphyxia. This risk is negligible most of the time, and manageable even in the worst of times. But any risk of accidental death must be taken seriously.
Most of the research on positional asphyxia focuses on the prone restraint position. When a suspect puts up serious physical resistance, it is most advantageous to get him down on the ground in the prone position. Held prone, the suspect can't strike with his fists, can't kick, spit or bite, and mostly can't even see. To hold a suspect in the prone position, an officer can place bodyweight on the suspect's back or neck, typically with a knee. The officer can now get one or both of his own hands free, while effectively restraining the suspect. With his own hands free, the officer can use his radio, apply handcuffs, etc. From the point of view of subduing an aggressive suspect with a minimum risk of injury to everyone involved, prone restraint with bodyweight is as good as it gets.
Just like every other thing, prone restraint has limitations and risks. Bodyweight on the suspect's spine invariably causes at least some respiratory difficulty. If much weight is placed on the thorax, the difficulty will be severe, requiring strong effort to expand the chest. Sometimes, in the face of respiratory difficulty, a suspect's resistance will only increase. The combination of physical struggle and reduced oxygen can lead to sudden asphyxiation. If an officer becomes concerned about this possibility, he faces a choice:
Take the weight off. The suspect will breathe and recover, which is good. The officer gives up some effectiveness of restraint, which might be bad. The scene might re-escalate once the suspect gets some wind in him.
Power through. Get the cuffs on before taking the weight off. Once the cuffs are on, immediately remove the weight and roll the suspect onto his side (recovery position).
Neither of these choices gives real certainty as to the outcome, and no two situations are quite the same. At some point, however, the officer must get the cuffs on. A few rare suspects fight to the moment of becoming unresponsive. No officer likes to be in this situation; the combination of struggle, asphyxia, and unresponsiveness can be deadly. Even with prompt, appropriate action by the officer, the unconscious suspect may not be breathing enough to recover.
Among the numbers of people who die in this way, cocaine users are over-represented; their behavior may have something to do with the exciting, confidence-building, numbing qualities of cocaine. Because of this association, "excited delirium" is the accepted euphemism for asphyxiation under police subdual and restraint, when it happens through no fault of the officer.
The other way a person can die of positional asphyxia is simply by being ignored while handcuffed in the prone position. In breathing, the chest wants to expand forward, which is less convenient if there is a firm surface in the way. For most people, the resulting respiratory difficulty is no worse than moderate discomfort. But if the suspect is fat, drunk, and unable to roll over, this position with the arms pinioned by the sides can be deadly. Accidental deaths have resulted from loading and transporting a handcuffed suspect in the prone position, so police never do that even with fit, sober people.
Prior to transport, though, handcuffed suspects may be temporarily restrained in the prone position, though usually without bodyweight restraint/subdual. For instance, some handcuffed suspects kick, spit or bite, and prone restraint will put a stop to that nonsense while the officers figure out what to do. Because the officers are not ignoring the suspect, the danger of asphyxia is nil.
Derek Chauvin positioned George Floyd prone, in handcuffs, and placed bodyweight on Floyd's thorax. This combines both elements of risk for positional asphyxia. In terms of taking chances with a suspect in custody, this is about as close to the sun as an officer can fly. Is it even legal?
In law enforcement training materials, it is rare for a technique to be explicitly proscribed. Instead, when high-risk interventions are contemplated, the training materials provide a general warning. For instance, using force against a handcuffed suspect puts the officer at risk of excessive force and possibly a violation of his duty of care. Here's what Minnesota's Model Policy For Use Of Force has to say about that:
Physical force shall not be used against individuals in restraints, except as objectively reasonable...
Here is similar language from the DOJ Positional Asphyxia publication:
...the use of maximal, prone restraint techniques should be avoided. If prone positioning is required...
"It is bad to do this except when it is required" seems like weasel language, but it implicitly acknowledges an ethical reality: in police work, you just never know what you might have to do. In an exceptional situation, a merely-bad option might be the least-bad option. And police have few enough options; they really don't like to rule anything out. Earlier I said the police never transport a handcuffed suspect prone; but what if the suspect has an injury to his buttocks and can't sit or lie on his side? They might have to do it. For any situation like that, the rules are:
Don't do it unless you have to.
If you have to do it, know the risks/actively manage the risks, AND
Do it as little as possible; stop doing it as soon as possible.
Was Derek Chauvin's use of force against George Floyd "objectively reasonable"? That turns out to be a subjective question. We have the benefit of hindsight; Chauvin had the benefit of actually being there. However strongly we may feel that Chauvin's restraint of Floyd was excessive force, Chauvin could claim that he thought he had to do it, and there isn't an objective way to prove him wrong. We might say Chauvin took unacceptable risks with Floyd, but that doesn't mean much if the risk is manageable.
The prone restraint position comes with risk, and any officer who employs it must manage the risk. He does this by paying close attention to the suspect, alert for changes in breathing or level of consciousness. If he sees the warning signs, he can ease the pressure, to keep the suspect safe. The risk of death is real, but the actual danger of death is very slight, so long as the officer is alert to the risk. This is why prone restraint and subdual with bodyweight is not categorized as deadly force: done with due care, it is very unlikely to kill.
If the suspect is already handcuffed, and if more than one officer restrains the suspect, the risk of positional asphyxia is one-hundred-percent manageable. There is no chance of re-escalation. The essential factors in asphyxia - bodyweight restraint and prone position - are under the officer's knowledge and control. With a minimum of diligence, positional asphyxia poses no danger at all. So leave aside the question of whether it was excessive force or unacceptable risk. The question is, did Derek Chauvin manage the risk?
Derek Chauvin ignored the risk. He did not make sure Floyd could breathe.
Any time a struggle on the ground ends with the suspect in restraints, the first consideration is to get the suspect off his belly, typically in the recovery position. Did Derek Chauvin end the struggle? Did he stop as soon as possible? Did he place George Floyd in the recovery position?
No.
The Medical Examiner's Report Exists
In its top line, the ME report mentions "neck compression". This has caused some confusion, because neck compression isn't a total theory of the case.
George Floyd's neck wasn't exactly compressed. Chauvin never encircled Floyd's neck, and his position was not ideal to bring weight to bear on the soft front of the neck. Floyd's neck was, however, hyper-rotated. At one point, the pressure of Floyd's face on the pavement was enough to push his jaw and tongue out of line. So Floyd's airway wasn't compressed much, but it was twisted and stretched, and this would contribute to his breathing difficulty. At least some of the time, it would take an effort to keep the airway open. This is significant, but it’s not the whole story.
Floyd was restrained in such a way that his chest couldn't expand forward, and he had to lift Derek Chauvin's bodyweight with every inhalation. The rib muscles are not made to lift a heavy load like that. The remarkable thing is not that Floyd went into respiratory distress; it's that it took so long. Floyd inhaled roughly eighty times in four minutes, which is a lot of push-ups. It didn't help that Kueng restrained Floyd's hips. Had Floyd been able to raise his hips, he could have made some room in his abdomen for breathing.
At least some of the time, Chauvin's knee appeared to be more on Floyd's left shoulder than on his back as such. That's still pressure on the thorax: the shoulder blade is on top of the ribs, which are connected to the spine, which is connected to the rest of the ribcage. For that matter, the neck is connected to the ribcage. A strong enough pressure on any part of the chest affects the movement and functioning of all. Give Chauvin credit; the guy knew what he was doing. By pushing inwards from the side, Chauvin added effective weight to his knee and restrained Floyd from rolling to his left. Floyd struggled to roll, again and again; Chauvin's weight held him down. The effective weight, as much as 150 pounds including Floyd's own weight, was aimed pretty much at Floyd's breastbone.
Another aspect of the ME report that has caused confusion is the heading of part III of the Final Diagnoses, "No life-threatening injuries identified." The ME went to some trouble to rule out occult trauma, airway trauma, and a host of other pertinent negatives. This led some to believe that the ME report had ruled out traumatic asphyxiation. In fact, the report does not explicitly rule out, nor does it specify, any cause of death. It does not contain the search terms "asphyxia", "homicide", or "excited delirium".
If a body is dead and no cause of death is evident at autopsy, that actually narrows the possibilities to asphyxiation (medical or traumatic), or neck compression as by a "blood choke". Neck compression doesn't convincingly suffice, so that leaves asphyxiation by Fentanyl, heart failure, or Derek Chauvin. Chauvin is a definite possibility. Prone restraint with bodyweight causes respiratory difficulty. It doesn't cause occult trauma, or petechiae, or swelling of the airway; the absence of those findings proves nothing. If prone restraint could cause life-threatening injuries, the police wouldn't do it. But it can kill.
The ME, Dr. Andrew Baker, was called to testify at the trial. He testified that, on the day of Floyd’s autopsy, he told prosecutors there was no physical evidence of asphyxia. Again, some people took this out of context; death by asphyxiation doesn't usually leave any physical evidence other than the dead body. Baker's other testimony was more to the point.
Floyd's body bore numerous marks of violence. A few of the highlights include:
14 cm maximum dimension pink-purple contusion with a discontinuous 8 cm maximum dimension dried red-black abrasion, left shoulder
Patterned contusions (in some areas abraded) of the wrists, consistent with restraints (handcuffs)
Circumferential, discontinuous, 3.5 cm maximum width, roughly parallel pink-purple contusions encircling the right wrist, with areas of superimposed abrasions up to 1.2 cm maximum dimension;
Circumferential, discontinuous, 2.5 cm maximum width, roughly parallel pink-purple contusions encircling the left wrist, with areas of superimposed abrasions up to 1.3 cm maximum dimension - On the anterolateral left wrist, in a 3.5 cm long area, the injury transitions to a dried yellow-black abraded furrow before blending into the anterior wrist crease.
Finally, in a separate section on Special Procedures:
In the left wrist, there is multifocal fascial hemorrhage, with approximately 3 mL liquid blood accumulation, in the tissue surrounding the flexor tendons.
The video doesn't show exactly when or how most of Floyd's injuries happened. But the cause of the wrist injuries is plainly to be seen. Once Floyd was down, Chauvin took a grip on the fingers of Floyd's left hand, and pulled Floyd's wrist into a hyperflexed position, using the shackle of the handcuffs as a fulcrum: pain compliance. Chauvin never released this grip, and the angle of Floyd's wrist only became more acute with each passing minute. In the end, that wrist was sprained.
Floyd struggled to roll over. His core strength wasn't enough to twist him out from under Chauvin; he reached to push with his right hand. Had Floyd's right hand been free, he could have pushed against the pavement or the wheel of the car, and he could have rolled. But he was handcuffed. His right hand and fingers strained, continuously, to reach any kind of purchase. His wrists became battered and abraded as he struggled; the left shackle gouged about halfway through the skin on the thumb side of his wrist. At the same time, Floyd's left shoulder was bruised and scuffed as though someone worked him over with a sanding block.
Those are the marks of a struggle in agony. The pain of asphyxiation overrides other discomforts.
That shoulder on the pavement must have burned. But Floyd squirmed with all his might. That sprained, abraded wrist must have been tender. But Floyd pulled against it with all his might.
Those are the marks of asphyxiation.
The Video Exists
Of all the notable deaths in American history, the death of George Floyd is unique in being exhaustively documented in video. Most of the video is in the public domain. Anyone can review the bodycam videos of Thomas Lane or J. Alexander Kueng. The cellphone video by Darnella Frazier was the first document to go viral. All these videos depict the death of George Floyd in close-up, wince-inducing detail.
The video is by far the most important evidence in the case. It is also the least-examined and least-understood. After all the furor and debate over the death of George Floyd, it is passing strange if, three years later, an amateur review of public evidence should turn up even one fact not commonly known, let alone tell a story that hasn't been told. Yet here we are.
Any true theory of the case must stand examination in the light of the video. If someone claims that George Floyd died from complications of childbirth because the officers had no way of knowing the fetus was a pumpkin full of mice, you can dispute that claim with ordinary facts and reason. If that fails, you can always point to the video, which does not depict any of that stuff. Even if the pumpkin theory could be true, it can't be true if the video doesn't depict it.
We have three theories to choose from. One theory is depicted in the video, so it might be true. The other theories are not depicted.
The Overdose Theory Redux
George Floyd's medical presentation when Thomas Lane first saw him, was as follows:
Responsiveness (alert, verbal, pain, unresponsive): alert
Level of Consciousness (person, place, time, event): 4/4, "conscious alert and oriented"
Altered Mental Status: mild confusion / attention deficit
Neuromuscular Deficit (speech, gait, posture, balance, reflexes, muscle activation): no deficit
Trends over time:
Increasing awareness and mental focus
Increasing anxiety
Increasing pain
Increasing respiratory effort
That can't be a Fentanyl overdose. Here's what we know about the outwardly-visible effects of Fentanyl on George Floyd that day:
In the store: neuromuscular deficit (surveillance video)
In the car, later: reduced consciousness / inability to converse (Shawanda Hill in court testimony)
When Lane found him: mildly confused
When Chauvin found him: sober and scared
Most likely, Floyd met his drug dealer and took a hit right away, then went into Cup Foods. His time in the store was enough to partially absorb the drug, with visible effects on his carriage and demeanor. Once he made it back to the car, he took a nap. When he woke up from his nap, he was soon alert. The exact timeline of these events is unknown. The reported duration of the effects of Fentanyl is 2-4 hours, but that's in a medical setting. For Floyd the effective dose - enough to get him high - was a high blood concentration, a short-lived "peak". So Floyd could take a pill, go on a little trip, and be back before the other people in the car got bored. For 2-4 hours after that, Floyd would presumably have been untroubled by withdrawal.
If he did take more Fentanyl after that first dose, it failed to absorb before he died.
The Heart Failure Theory Redux
Thomas Lane interviewed Shawanda and Morries, then rejoined George Floyd and Officer Kueng. As the three started towards the squad car, there was this exchange:
Kueng: (unintelligible question) ("foam around your mouth?")
Floyd: "Yes! Yes! I was just hoopin' earlier."
Kueng really did say "foam around your mouth", and Floyd really did say "Yes" and "hoopin". Neither of these subjects ever came up again. What do they mean?
Some have taken these things to mean that Floyd was, in fact, foaming around the mouth. In turn, this has been taken as evidence that Floyd was in emergent heart failure. The foam around Floyd's mouth was pink frothy sputum, expelled from Floyd's lungs: proof of pulmonary edema.
At no point in the video is this foam visible. In the first few seconds after contact, we see Floyd's face close up, and for a frame or two there appears to be a narrow line of white foam or crust near Floyd's upper lip. That could be anything. It could be toothpaste or residue from a banana. It could be drool from when Floyd dozed off, slumped over his steering wheel.
It can't be pink frothy sputum. For one thing, that stuff is pink. It looks bloody gruesome coming out of someone's mouth; it wouldn't get just one passing mention.
In order to cough up crud from the lungs, a person must cough. At no time did George Floyd cough, splutter, gag or gulp. Even without these actions, an airway full of liquid is noisy. It makes gurgling, rattling, frying sounds. Floyd's respiration was noiseless except when he vocalized.
Floyd's respiration was also effortless until Chauvin put that knee on him. There was no posturing, no straining, nothing at all to indicate breathing difficulty.
Kueng's mention of foam was about three minutes before Chauvin arrived. If George Floyd had been as far gone as this theory claims, he wouldn't be capable of any effort other than breathing at that point. By the time Chauvin arrived, Floyd would have been at or near collapse, and anyone within fifty feet would see he was deathly ill. Floyd looked fine.
After Chauvin arrived, Floyd exerted himself at about 90% of his capacity, for about six minutes. That can't be emergent heart failure.
The Positional Asphyxia Theory Redux
From the transcript:
Floyd continues to cry out with every exhalation, but his cries are getting quieter.
Floyd: "(unintelligible) kill me. (unintelligible) kill me. I can't breathe."
Kueng (remonstrates with bystander): "We tried that for ten minutes."
Lane: "Roll him on his side?"
Chauvin: "(inaudible) staying where we got him."
Lane: "OK. I just worry about the...excited delirium or whatever."
Chauvin: "That's right, we'll (inaudible)"
Lane: "OK. It's close."
Bystander 2 (to Chauvin): "(inaudible) doing that shit man. You're a fucking bum. You ain't doing that shit right now bro. Should have put him in the fucking car by now. Look at you, his body language is (faint)."
Floyd's right elbow droops towards the pavement.
(Forward to Part Five: None Of That Matters)