Stopping the sedation!

Let’s be unambiguous about this – the announcement that Michael’s care team is discontinuing his sedation is the news we’ve been waiting for. It’s the first big transition – from acute, life-threatening head injury to subacute recovery. Followed no doubt, let’s not forget, by a chronic rehabilitation phase. But this is wonderful news.

In terms of how this is done, well it’s actually pretty simple. The electronic pumps driving the continuous infusions of the sedative drugs are turned off. That’s it. But doing that means that the people taking care of Michael have a reasonable expectation that he will not exhibit untoward reactions to the “stress” of these medicines being turned off. The most undesirable of these would be elevations in . . . you guessed it . . . intracranial pressure, but to be honest, we’re now more than four weeks post-injury, and I’d rather think that we’re past that.

So what will happen now that this stuff is turned off?

1) It may or may not be true that, in general, French neurointensivists maintain sedation longer than their Anglo-Saxon colleagues. It doesn’t matter. The people taking care of Michael know what they’re doing.

2) while it’s possible that a long-acting drug may well have been used in the early, “suppressive” phase of Michael’s care, it’s quite likely that if so, it’s been replaced with one or more short-acting substances. These usually allow signs of emergence to appear within several hours of stopping the infusions.

3) What actually happens? Well in general, the first attempt to stop sedation usually gets interrupted by something. The patient gets agitated, the blood pressure goes up, the oxygen saturation goes down . . . something. So you turn the sedation back on, let the situation settle down, and then either try again or wait until tomorrow. It often takes a few tries before everything goes the way it should.

How should it go? Well ideally Michael will start to want to breathe, and allow weaning from ventilatory support. And just as important of course he will hopefully start to show meaningful interaction with his environment. Following simple commands, visual tracking, etc.

Now I’ve heard (from unconfirmed sources), unconfirmed reports (double “unconfirmed” should ring alarm bells of course) that Michael has indeed already done this.

I’d love any neurosurgeons to jump in and comment, but if this indeed is true, it is fairly astonishingly good (but indeed totally conceivable) news. So we need to cross our fingers and hope something like this DOES get confirmed in the future.

Tell you what – let’s not talk about any other alternatives right now, ok, so we keep it positive.

One last thing.

I’ve seen some very heartfelt comments here and there about articles, tv pieces, and blog speculation “hurting” Michael’s family. I wanted to just weigh in for a second.

I’ve been pretty harsh with the tabloid press, and deservedly so. But not because the Daily Mail’s moronity hurts Corinna, Gina Maria and Mick. ARE YOU KIDDING? Could they possibly hurt more? And if so, is it likely to be because of the suffering induced by a British rag? Of course not. I think it’s detestable coz it’s shit “journalism”. I kinda don’t think it’s on Corinna’s reading list, I don’t think their “journalism” could possibly add to their pain, and lastly, Michael’s care team have no doubt been TOTALLY up front with the family. Meaning they have a better idea than any of us of just what the . . . hell . . . is up.

If I thought for a second that anything I’ve written might hurt Michael or his family, I’d not have written it. To be honest, I’ve spoken to you as I’d speak to Michael’s family. I assume you know that, because I think it’s to THAT that you’ve reacted (to my infinite astonishment), more than to the information that I’ve transmitted.

Catching up with questions and comments

I wanted to just reply to a few comments and questions that have appeared here and on Twitter. I’m very gratified that so many people have clearly been thinking about this stuff.

I think we can and should generalise what I said about ski helmets to just about any realm of activity where they are “counted on” to provide protection. Construction hard-hats, bicycle helmets, hockey, Formula 1 pit crews, etc. The injury patterns almost certainly are different in each endeavour, and each therefore probably needs a different helmet. In general, we can’t expect the end user to do anything except have confidence in the equipment he (or she, that’s assumed in all my blog posts) chooses to use, or is obliged to use. That means that those who supply those helmets need to have a good idea of exactly what sort of injuries they need to mitigate. Clearly access to an appropriate level of protection has to be monetarily feasible. I chuckle to hear national-level rally drivers complain about a €2000 helmet (before going out and spending more than that on a set of tires! Helmets don’t make you fast!). I assume that a top of the line ski suit costs at least €800-1200. So that’s a constraint within which the manufacterers will have to work. They’re smart people. They’ll figure it out if the data gets generated.

Measuring g’s at the helmet with accelerometers is interesting, but there are severe enough problems with coupling to the head to make this data almost unusable in terms of BRAIN g’s. The DoD, and the FIA Institute, have been working on earpiece accelerometers for some time. These incorporate tiny 1 x 1 x 1 mm triaxial accelerometers into the part deepest into the ear canal. While this should theoretically give robust values for BRAIN g’s, that’s not happened yet. IRL has used earpiece accels for a while now, but I’m not sure they’re generating clinically useful data . . . yet.

Several people have sent me clippings concerning the effects of fish oil. Apparently someone “woke up” a comatose child using mega doses of fish oil. The explanations given were something like, well the brain is made up of fats, and so we give this good fat and it’s anti inflammatory too. The problem is that the person who administered this treatment published his results . . . on CNN. He should have published them in a peer-reviewed journal. Call me old-fashioned, but in terms of TREATING (not experimenting on) human beings, good quality evidence is the way to be guided, not what you saw last night on Dr. Sanjay Gupta’s show. That said, were I to be the close relative of a comatose head trauma patient, and were i to be  convinced that the risk profile of this kind of use of fish oil was acceptable, it is entirely possible that I’d be willing to have a go. But at the moment, let’s be clear, this is closer to ritual incantation than to medical science.

Lastly, something that’s been bothering me. A lot. As a doctor who practices pre-hospital medicine regularly.

Here goes: why was Michael brought to the hospital at Moutiers initially, and not to a neurosurgical centre? I am not trying to second guess (ok, just a bit) my colleagues who landed there on the 29th of December . . . BUT

• reliable witnesses report to you that the victim hit his head
• the victim’s helmet has been damaged in the impact
• there’s blood on the snow
• there is obvious signs of an open head injury
• the victim is agitated (in any event his behaviour is not ENTIRELY normal)

Now I’m sorry, but it doesn’t take a doctor to put this together and figure out, “hey this person may have a head injury”.

Thing is, it is a general principle of pre-hospital medicine to take a patient to the closest APPROPRIATE facility. In a given Emergency Medical System’s territory, if this is applied “conservatively” it pretty much ALWAYS includes, for example paediatric cases and potential head injury. Thing is, there’s no neurosurgery at Moutiers. Why then was Michael brought there?

This question needs to be answered. As devastating as the injuries produced directly by the fall are, any delay in proper airway control and neurosurgical intervention cause further damage and must be minimised.

I raise this point simply because local protocols should be reviewed, and adjusted appropriately, in order to optimise the time it takes to get head-injured skiers cared for appropriately.

Some fascinating calculations, and one conclusion

Lots of people have asked me about the kind of forces involved in producing injuries similar to those Michael has suffered. It’s an interesting question, and after doing some calculations, it’s emphasised to me something that I think must be done relatively urgently. More of this later.

Let’s make a few assumptions as to baseline conditions. This means any results are at best approximations of the real world, but they allow us to “ballpark” the forces in question, and to perhaps compare with other mechanisms. And while I’m on the qualifiers, I’m SO not a physicist!

I’m assuming that the mechanism of injury is a near vertical fall onto the head, after Michael was “launched” by contact with a rock. I’ll assume his head was at 2.5 meters, not unreasonable for this kind of mechanism (and only slightly higher than one’s own height), that there was only a vertical component to his movement, and that he weighs 70 kg. This results in an energy of 1715 joules. Never mind the units for the moment – we’ll just generate some more energy data and then compare.

How about Felipe Massa’s accident? We know the spring weighed 800 gm (0.8 kg), and that Felipe was moving at 260 km/h (the spring is considered to have no horizontal velocity). This gives an energy of 2085 joules.

The same kind of calculation shows us that the bullet from a Kalashnikov (7.9 gm, muzzle velocity of 715 m/s, thanks Wikipedia!) has . . . 2019 joules!

To compare some other energies, let’s look at a soccer player heading the ball. Just to simplify, I’ll assume the player has no vertical speed when he heads the ball, and that the ball is falling from, say, 20 meters. This gives a “measly” 86 joules. Nothing, eh? (The actual value will be higher because of the player’s vertical momentum, and also if the ball falls from higher). Well how about this: there is a direct correlation between a the number of heads a soccer player has in his career and his cognitive function. So even this relatively tiny force, repeated many times, will likely damage a brain!

What about American football, where we read every day about cases of chronic traumatic encephalopathy (the damage done by years of hits)? Again, a few assumptions. Defensive lineman, 100 kg. Offensive lineman, 150 kg. Speed of each at impact? 1.2 meters/sec. What does this give? This gives us 180 joules combined. Again, doesn’t sound like much, but repeated over a career from high school, through college, to the pros, it seems often to result in very significant damage to the brain.

But back to the object of our concern. What explains the dramatic difference in outcomes between Michael and Felipe?

The obvious first (and perhaps only significant) answer is their helmets. Felipe was wearing the latest spec full face carbon kevlar racing helmet. Michael was wearing a . . . ski helmet.

Remember that force is not the only factor – we have to consider the area over which the force is spread. When a 70 kg man steps on your foot with his loafers, it hurts, but nowhere NEAR as much as when a 70 kg woman does the same with a stiletto heel. In one case, the force is spread over a much larger AREA, giving a lower pressure. And it’s pressure that actually does the damage. One of a helmet’s main roles is to distribute a force over a (much) larger area, dramatically reducing the pressures generated.

Now, the FIA Institute has done remarkable applied research in helmet design, and the helmet Felipe was wearing reflects that research. This helmet was designed specifically with very demanding requirements for impacts with objects having rounded edges as well as those having sharp edges, and equally for penetration resistance. These requirements were based on known mechanisms of injury in the sport concerned, and the levels of energy seen.

Ski helmets, on the other hand, are designed and homologated (WHEN they’re homologated) almost solely to prevent skull fractures. While this provides an easy method of evaluation in testing labs, we know that this has VERY little (if anything) to do with the actual mechanisms of brain injury. And unfortunately, Michael is a living demonstration of this.

Therefore, I’d like to throw a few ideas out there:

• the Federations responsible for skiing, from recreational to competitive, should convene a working group of experts to look at the epidemiology of head injury in the sport
• conclusions should be drawn about the kind of head protection likely to mitigate the injuries ACTUALLY SEEN
• Jean Todt should offer the full resources of the FIA Institute (data, expertise, etc) to help design this helmet, to make it affordable, and to make sure it is used as widely as possible.

Michael’s injury is no more tragic than those of every patient who suffers severe head trauma. If, however, his public persona spurs action that goes on to significantly improve the safety of skiing, it will be another of his many remarkable accomplishments!

What may be going on now, and where this might be going (long, speculative and detailed)

The Daily Mail has done it again. With today’s headline they’ve “forced” me to take to my blog to help clarify some of what’s being said.

As with everything that I’ve said, tweeted or written since Michael’s accident, I need to make clear that I have not seen Michael, not seen his scans, and not had any contact with the medical team caring for him. I’m going to base the following on what has been said by his care team, on the things that have not been said (by anyone), and on my clinical experience (and that of colleagues) with similarly injured patients.

What is likely happening now? Michael is almost certainly still in the Intensive Care Unit (ICU). I say this primarily because it is rather likely that he still requires this level of care given his injuries, but also because had he been moved from the ICU to a normal room, this would have been sufficiently newsworthy to have almost certainly been announced. If Michael’s breathing is still handled by a respirator, he will almost certainly have had a tracheostomy done. This is more comfortable for the patient, spares the patient from potential damage to the vocal cords, and can make weaning from the respirator easier. It can also be easily closed later, when appropriate.

More importantly is the question of the “artificial coma”. Now those of you who’ve been reading me since the beginning have no doubt noticed that I HATE the term “artificial coma”. It’s confusing and doesn’t transmit any useful information. Initially Michael was no doubt maintained at a VERY deep level of sedation, deep enough to virtually suppress most electric activity in the cerebral cortex (the outer layer of the brain, responsible for higher intellectual functioning). This was done to help manage what were extremely high and dangerous levels of intracranial pressure (ICP, see previous blog entries).

Now that the acute phase of the injury has largely passed, it is almost certain that ICP is no longer problematic. The swelling and bruising are being resorbed. This means that the sedation will certainly have been lightened. Remember that having a tube in the windpipe is a pretty significant and painful stimulus. So sedation is almost always needed to help the patient tolerate the tube, to allow mechanical ventilation, and permit all the other “aggressions” that are part of day-to-day ICU routine. If this is the case, then the care team will be repeatedly, and considerably, lightening the sedation, in order to start weaning Michael from the ventilator, and to allow neurologic evaluation.

This would be good – if the sedation is light, and if respiratory weaning (getting Michael to breathe by himself) is progressing, with a neurological status that allows this, then we can relax for a few weeks, and see how the situation evolves. This situation would mean progress has been made, and renders further prognostication impossible. Progress will continue at an unknown and unknowable speed, and will stop at an unknown and unknowable level of function.

It is also conceivable, at the other end of the “goodness” spectrum, that the sedation has been turned off, that Michael is tolerating the tube, but is neither breathing adequately on his own nor showing significant signs of emerging. You understand that tolerating a tube with no sedation implies rather severe problems with deep levels of the brain, as does the lack of adequate breathing despite stopping the sedatives. At three weeks post injury, this is the worst outcome we could hope for, as it would indicate a rather high probability that normal consciousness will not be regained.

A brief word about the terms “critical” and “stable”. First of all, as used with respect to the condition of hospitalised patients, neither is precisely defined. So it’s important to see them rather more like an impressionistic image than as an accurate statement of  physiology. Critical means imminent life threat or threat to a vital system. Stable means that something is not changing, and is usually being maintained within normal limits. So Michael is no longer CRITICAL (the ICP has normalised), and STABLE, as his physiological parameters are now acceptably “constant”.

Ok let’s get down to the hard stuff here. What are the possible outcomes? I’ll look at some of them, mostly with an eye to defining terms we’re likely to see thrown about in the near future, so that we can be precise ourselves, and be critical when faced with imprecise, ambiguous, or misleading information from others (are you listening Daily Mail?).

Now remember, all we know with certainty about Michael’s injuries comes from the press conferences given by his care team. After explaining the how and why of evacuating the right-side extradural hematoma (on the Sunday) and then the left-sided intracerebral hematoma (on the Monday), the neurosurgeon let slip a VERY telling statement.

I’m almost quoting him here, translating from the French. He said “don’t think that we evacuated two hematomas and that’s it”. “Michael has lots of hematomas in his brain, on the left, on the right, and in the middle”.

Damn. See, the “middle” is where all the important stuff happens – awareness, arousal, control of blood pressure, respiration, swallowing etc. And the left – well that’s usually language. Etc etc. The neurosurgeon, intentionally or not, painted a rather catastrophic neurologic picture.

First off let me say that it is EXTREMELY unlikely (I’d honestly say virtually impossible) that the Michael we knew prior to this fall will ever be back.

I think that it will have to be considered to be a triumph of human physical resiliency, and of modern neurointensive care, if Michael is able to walk, feed himself, dress himself, and if he retains significant elements of his previous personality. If recovery proceeds to this point (which is totally POSSIBLE, if perhaps rather improbable), it is an open question as to how well the “higher functions” (memory, concentration, reading, planning, etc) will recover. Please note, I would love to be proven wrong about this! 

At the other end of the spectrum would be continued coma. Coma is defined as a state where there is neither wakefulness nor awareness (the patient cannot be woken by stimuli), no meaningful interaction with the environment, and no voluntary actions. This is obviously catastrophic. This outcome is entirely possible based on what we know about the brain’s primary injuries (the fall, the hematomas, bruises, etc) as well as the relatively long period with high ICP.

It happens that patients in coma emerge sufficiently to show spontaneous eye-opening, and even sleep-wake cycles (demonstrating wakefulness or arousal), but show no interaction with the environment, and no signs of any higher function (thought, speech, etc). This is called a vegetative state. Definitions vary somewhat, but usually after four weeks it is termed a persistent vegetative state, and after one year it is called a permanent vegetative state. Very roughly speaking, about 50% of head trauma patients who are in a vegetative state one month after injury become conscious, often with significant neurologic impairment. If the vegetative state persists for six months, this falls to roughly 20%, usually with severe impairment. After one year, resumption of normal consciousness is very rare, and, when it happens, function is usually gravely altered.

Whereas a patient in a vegetative state shows no signs of awareness, a patient in a minimally conscious state will show definite signs of awareness of either self and/or of the environment. This may include obeying simple orders, some intelligible language use, or other behaviors that seem “goal directed”. Examples would be appropriate emotional responses, appropriate eye tracking, consistent and appropriate movement or vocalisation in response to language (not just sounds). These signs usually fluctuate through the day, and over time. Importantly, the chances of meaningful recovery from a minimally conscious state are higher than from a vegetative state. They are however, still disappointingly low.

There is certainly reason for worry – lot’s of worry. But no reason to lose hope. Everyone who works with head-injured patients has seen VERY severely injured patients (who were not expected to do well) recover acceptably. All we can do is wait, pray, and be behind Michael and his loved ones.

 

 

An incredibly important piece to read

An incredibly important piece to read

David Brooks is a rather conservative columnist, but he usually stays away from politics per se. He is one of the most brilliant men around – and this is proof of that. For everyone who is following Michael’s story, whether you’re deeply involved and suffering along with Corinna and Michael’s loved ones, or more removed from the tragedy, this column helps clarify the deeply human side of how we handle the suffering of others. Please find the time to read this. I have no doubt everyone who does will finish it just a slightly better and fuller person. Yes, it’s that important.

In the absence of any news from Grenoble, I’ll blog soon about some of the terminology that people are going to start throwing about at some point in the not distant future, and some of the possible outcomes we can expect.

Meanwhile, I hope you love this piece as much as I did.

These recent reports

It seems an article in The Daily Mail has everyone concerned. I’m being asked what I think. Here goes.

I hope we’ve all been VERY worried since the first reports of Michael’s accident. That surely is the appropriate attitude.

The guys quoted in the online article I saw have taken care of patients like Michael. They have not, however, examined Michael, reviewed his scans, etc. Because their titles imply that these men are consummate professionals, I’ve no doubt that they made clear (much clearer than the Mail does) that they were speculating as to possible outcomes.

Because that is what they are doing.

Look, I think that we need to look at this speculation rather like the arrival time estimates of your satnav. Their initial estimate is based on some assumptions and statistics. Obviously, as you get closer and closer to the destination the estimate gets better and better. Duh.

It is highly unlikely that when Michael and his family are finished with hospitals, finished with rehab centres, he will be the same Michael we had known until that Sunday.

Having said that, which is admittedly saying very little that isn’t, unfortunately, painfully obvious, the range of impairment we may see spans the spectrum from mild sensory/motor/behavioral problems to more dramatic sequelae.

Once again, patience, long painstaking work by all concerned, and just maybe our thoughts, best wishes and prayers will be needed. Long periods with no news are perfectly normal, and will remain so. We will likely enter a chronic phase, punctuated by (hopefully) several steps forward and (hopefully) many fewer backward.

John Button

One of my favourite people in Formula 1 has left us.

John Button was a man who got so many things right. 

John raised a son who has kept his head firmly on his shoulders despite the mega-stardom that his career has brought. I remember checking in at the Suzuka Circuit hotel next to John and Jenson. John insisted there be an iron in Jenson’s room. I was a bit surprised, and John saw the quizzical look on my face. “He irons his own shirts man, and he always will”, he told me. Jenson just smiled. It’s not easy to raise a talented child, and even harder to raise him or her balanced and healthy and good. John made that look easy.

Rather than try to (micro)manage Jenson’s career, John stepped back, and clearly spent the last bunch of years pinching himself. He thoroughly loved the life that Jenson’s success brought him, but never took it as HIS success. He was humble, full of joy, and a true bon vivant.

John, I’m gonna miss you . . . a lot. I treasure having met you and spent time with you. Jenson, my deepest condolences to you and everyone you love, and to everyone who loves John. Remembering our talks, time we spent at the bar in Sao Paulo, and other lovely moments, will keep John present for me.

Bye John. God speed.

Evaluating depth of coma

While we are all being remarkably patient (we don’t really have a choice, do we?) as Michael’s injuries heal and his state stabilises, I thought it would be useful for what’s to come to explain a bit of how doctors evaluate coma patients. This includes assessing how “deep” the coma is, as well as tracking the patient’s progress as the clinical situation evolves.

Now I’m sure that Michael’s care team will NOT be releasing any of this stuff when they begin lightening his sedation, but I still think it’s useful that we have an idea of what’s going on, how it’s done, and that we can interpret any details that do manage to filter out.

Because by definition a coma is defined as a prolonged state of diminished consciousness making meaningful contact between the patient and his environment impossible, we can’t just ask the patient a series of questions and go from there. What’s needed is a tool to evaluate more basic levels of brain function, in a reproducible, standardised and validated way. This tool is called the Glasgow Coma Score (GCS).

The GCS was described in 1974 by a duo of neurosurgeons working in Glasgow. For those of you interested in the original article, a landmark in neurointensive care, here is the reference:

Assessment of coma and impaired consciousness. A practical scale. Teasdale G, Jennett B; Lancet, 1974, July 13; 2(7872):81-4

The GCS involves observing the patient spontaneously, and if necessary determining his or her response to graded levels of stimulation. The initial stimulus is speaking to the patient. If needed, a painful (but harmless) stimulus is applied. There are several ways of doing this – steady heavy pressure on the forehead, deeply pinching the trapezius muscle, or deep pressure on a fingernail bed.

Three criteria are scored: the patient’s eye opening, motor response, and verbal output. As you can see if you look at the scoring criteria, the points for each parameter go from higher (representing a “higher” level of function) to lower scores, representing “worse” function.

In terms of eye opening, 4 points are assigned if the patients opens his or her eyes spontaneously, 3 points if they open to vocal stimulation, 2 if they only open to pain, and 1 if there is no eye opening at all.

Attention then turns to the patient’s verbal responses. Appropriate, oriented responses to simple questions get 5 points. Confusion or disorientation is scored 4; inappropriate, unrelated words “earn” 3 points. If the patient only makes incomprehensible sounds in response to stimulation, 2 points are given, and as with the eyes, if there is no verbal response only 1 point is given. Obviously this criteria cannot be assessed accurately when the patient is intubated, and this fact is noted, often by assigning a “value” of “T” to this criteria.

Motor responses are extremely important. If the patient follows simple commands (wiggle your toes, move your index finger, etc) he or she gets 6 points. When the response to the painful stimulus is an oriented attempt to remove the stimulus, 5 points are assigned. Next comes a withdrawal response (4 points), an unorganised series of movements representing a primitive response to escape from the stimulus. If the coma is still deeper, the patient will respond to painful stimulation with an abnormal flexion of the arms and/or legs (3 points), a response that originates in mid-levels of the brainstem. Still deeper is abnormal extension, because this is integrated at even lower levels of the brainstem. This is assigned 2 points. And as above, no motor response at all gets 1 point. If there is a difference in the response of the right and left sides, the BEST response is used in scoring (but the “score” of the other side is noted also).

As you can see, scores range from a high of 15 to a low of 3. The GCS score is evaluated quite often (several times a day), and provides a reliable and reproducible way of assessing whether the patient is “emerging”, “plunging”, or staying the same. It is also used to roughly stratify the severity of injury.  Scores from 13-15 are considered to be “mild” (and often correspond to what’s seen in concussion patients). Moderate head injury is present if the score is 9 to 13, while a score from 3-8 is defined as severe head injury. A patient with a score of 8 or less is considered to be in a coma.

The Glasgow Coma Score cannot be reliably evaluated until sedation is off, temperature is normalised, and other factors that could confound the scoring are taken into consideration.

Other elements are also evaluated of course including the size, symmetry and reactivity of the pupils, imaging, sometimes electroencephalography, in order to get a picture of how the patient is progressing and where the problem areas of the brain are.

Hope this helps.

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