Life Without the Boogeyman: Alternate Models of Emergency Spinal Care

Now that our review for Academic Emergency Medicine has been published, I wanted to devote a few words to a discussion that didn’t make it into the article.

We spent a lot of time trying to collate what’s known about one specific phenomenon: the blunt trauma patient with an “unstable” acute injury to his spine who suffers sudden neurological deterioration as a result of ordinary physiological movement. The reason we were interested in this event is because, whether or not we admit it, it’s the basis for our current model of prophylactic spinal immobilization. In other words, the reason we place collars, boards, and other devices on patients until they can be “cleared” is because we want to prevent this phenomenon from occurring.

Anybody who reads our review will probably deduce that we’re a little skeptical about this story. The available data is consistent with a clinical entity that is very rare, and when it does occur may be part of the inevitable natural progression of the disease rather than being a movement-provoked (and hence preventable) event.

This fits well with a rational understanding of the pathophysiology. The only mental model that explains the phenomenon of “sudden collapse” would be something like this: the spinal cord is intact, but is surrounded by a vertebral fracture which is both wholly unstable and contains some kind of knife-like bony structure which is poised to transect the cord given the wrong movement. Or perhaps: the bony integrity of the spine is totally lost at some level, and the cord is holding on purely by a few strands of nerve which (like guitar strings breaking) might pop loose with any movement.

These models might make sense to the naive layperson, but any medical professional who understands bones and nerves will have to admit that they’re a little silly. (A more realistic story of unstable spinal injuries, of course, is that disconnected structures compress the spine, causing real but much less dramatic sequela.) Do they never occur? Well, we can’t say that. They are not physical impossibilities, in the sense that they violate a law of thermodynamics or mathematics or grammar. But they are inconsistent with physiology — and in the absence of outcome data, physiological rationale is the only clay we’re working with.

How much room remains on the table for the sudden, irreversible event described in legend? At this point, it’s fair to say there is very little room. We cannot say there is none. There isn’t enough evidence for that. The knee-jerk EBM reaction is to suggest further study, but as Hauswald pointed out in his commentary, that may not be realistic. To make the distinction between “a very rare thing” and “nothing” would require a study of tremendous size, and even then a critic could still ask for more; proving non-existence is a philosophical impossibility.

But as pragmatists, we can say that “very very very rare” and “nonexistent” are clinically indistinguishable. It’s not impossible that beta blockers can cause anaphylactic reactions, that someone being operated upon could slip off the table, or that the hospital could lose power during a course of mechanical ventilation — yet we don’t feel obliged to inform patients about these risks. At some point, scenarios leave the realm of plausible and foreseeable sequelae and enter the territory of “anything’s possible.”

That being established, the question becomes this: if we banish the specter of the boogeyman, what are we left with? Does the entire concept of spinal immobilization become void? Am I an enemy of the board & collar?

No. Here are some alternate models.

The orthopedic model

This places spinal injury on the same level as other orthopedic diseases.

A patient arrives at the ED with a distal radius fracture. What do we do? We examine it clinically, we manage their pain, we obtain appropriate imaging to help guide our care, and — oh yes — we make some effort to immobilize the injury.

Why? Not because we’re afraid of any boogeyman. We aren’t terrified that if the patient lifts his arm and there is some miniscule movement, a hidden razorblade of bone will cut off his arm and render him immobile. Everyone would look at you like you were wearing a silly hat if you suggested that, because it’s a silly thing to say.

Nevertheless, it is probably wise to to make a good-faith effort at limiting movement around the site of injury. Unnecessary manipulation may promote further trauma to muscles, nerves, and vessels, which could induce unnecessary long-term morbidity, prolong recovery, or at least complicate management and increase acute pain.

And maybe that’s how we should view early spinal care. Nothing dramatic. No boogeymen. Just the same logical, unexciting approach that informs our approach to splints, slings, and casts.

You’ll notice that if we fail to apply those devices for five seconds, nobody freaks out, because it’s not that kind of intervention. You’ll also notice we can study their value in controlled studies without anybody gearing up for a lawsuit.

The “correlation is not causation” models

In our paper’s discussion, we briefly mentioned two possibilities that warrant further attention.

We are all supposedly clever people who understand how easily causation can be assigned to unrelated events, yet when a patient moves their neck or back, and shortly afterwards suffers neurological deterioration, we automatically assume that one caused the other. This is called “temporal association,” and while we can’t help but make the connection, it’s wrong as often as it’s right. (See the unfortunate coincidence of “vaccines caused my child’s autism.”)

Other than the cynical explanations of “this association never occurs” (probably wrong) or “it’s purely coincidence” (possible) there are two more sophisticated models worth considering:

The Unmasked Inevitability: An injury exists that would eventually have progressed to a worse neurological status (hours, days, or weeks later). However, the trauma of a movement event induces that deficit to present earlier. The long-term outcome is the same, but the deterioration is now temporally linked with the movement.
The Hidden Aftereffect: Early, unstabilized movement has no immediate effect, but the added insult to the cord promotes edema and other sequelae in the hours/days/weeks that follow. The end result is a poorer long-term outcome that could have been improved by limiting early spinal movement, yet with no obvious association between the two.

Both of these are extremely plausible pathways that we’ve proven to exist in many other diseases. Neither requires the presence of any boogeyman. And since both are completely unrelated to any naive temporal association, either one could only be detected using controlled, outcome-based studies, not this sort of childish anecdote-mongering.

The “forget it, I’m so done” model

Long spine boards may already be on their way out.

EMS services and hospitals around the country are beginning to get aboard the bandwagon of “ditch the backboard in most cases (but keep the collar).” This is very nice. But it’s interesting to examine why it’s happening.

There is no evidence for the benefit of either collars or boards. Any physiological rationale applies equally to both. (Yes, unstable C-spine injuries are somewhat more common than injuries at lower levels, but not so much as to make a difference here.) So why get rid of one but not the other?

It’s because the harms of boards are considered to be greater. There is more evidence that boards cause pain, stasis ulcers, respiratory compromise, and other negatives. However, none of these are major harms, nor are they terribly well demonstrated (most being shown only in small, unreplicated studies where a handful of volunteers were strapped to boards for a few hours). In other words, not exactly a knock-down argument.

If you believe that either device prevents serious morbidity, then these minor risks would not bother you. The only way that the side effects of backboards can be the deciding factor is this: you don’t really think there’s any benefit at all. Some harm + no benefit = out they go.

But remember that on any analysis, the benefits of boards vs. collars are equal zeroes. So once again… why keep one and ditch the other?

The true explanation of the backboard exodus seems to be that everybody finally threw up their hands and said collectively, “I’ve had it with these stupid things.” There was no landmark study or historical turning point. We just saw the writing on the wall.

Since they’re of a kind, the same thing might eventually happen to collars.

Do I think this would be a great idea? No. Because as we’ve discussed in this post, even if we exorcise the boogeyman from our thinking, that doesn’t mean there can’t be any benefit from these devices. It just means the possible benefit becomes more boring and less dramatic, and can now be studied, quantified, and weighed against other factors, rather than being an unassailable matter of dogma. And rather than burning our boards and collars, it means we’re free to recruit them in flexible and useful ways (such as using boards to move patients when it’s the most convenient method, or using collars to stabilize the necks of intubated patients when it’s helpful), rather than invoking them ritualistically.

So what now?

I hope these remarks shine a little light on some possible ways forward. I think many people feel that, if we drop the current model of early spinal care, we’re left with emptiness and nihilism. But really, the current model is based upon a fairytale: if we use our [talisman], we’ll keep away the [boogeyman]. Fairytale-based thinking prevents better understanding, because you can’t study a fairytale. Once we banish that, the entire disease opens up to the kind of rational approach that can stand alongside the rest of our armamentarium, and becomes amenable to the sort of boring explication offered by clinical research.

This is good. Do not fear it.

A Saga of Spurious Spines

There’s a story we’ve all been told. It goes like this:

A person suffers a traumatic injury, usually a minor one, like bumping their head or crunching their fender in traffic. Afterwards, they appear fine, without deficits or any great pain. Ambulance and hospital personnel are unimpressed. But all of a sudden, our seemingly-well patient makes some slight movement — maybe he turns his head — and instantly collapses to the floor, unable to move. He is paralyzed forever, and it’s all because of the unstable spinal injury that you missed.

You heard this cautionary fable in EMT or paramedic class. They tell it in medical school, in the emergency department, and on the trauma wards. It goes back decades. And it makes sense, right? Even a layperson would agree that if the structure of the spine is damaged, the cord it protects will become vulnerable, just like how you’re not supposed to poke the soft spot on a baby’s head.

In fear of this event, we go to great lengths to prevent it. We wrap collars around our patients’ necks, we tie them onto boards, we strap and tape and secure. If their spine can’t protect the cord, by golly we’ll protect it instead, at least until somebody definitively proves that there’s no injury. Which there usually isn’t. But still.

Here’s the trouble: practically nobody has actually seen this phenomenon of mechanical instability occur. For real; the next time somebody mentions it, ask if it’s happened to them. No, they’ll say; but my partner’s cousin’s babysitter saw it a few years back. And if you bother to track that person down, invariably you find that the case either never occurred or has become terribly dramatized through the telling. Steve Whitehead calls it the “Sasquatch event.”

So does this happen at all? After all, many things in medicine that make sense aren’t real. Indeed, doubt has grown lately as to whether our spinal immobilization precautions are effective, and we’ve become more aware of the harms associated with them; as a result, backboards have become increasingly vilified in recent years, and “selective immobilization” algorithms have been accepted in some areas. But there’s been less attention to the question of whether the disease itself is real or a myth, and I wanted to know.

So we went and looked. With the help of four folks smarter than me — Domenic Corey, NREMT-P; James Oswald, B.Emerg Health (Paramedic); Derek Sifford, FP-C; and Brooks Walsh, MD, NREMT-P — we canvassed the literature as far back as possible to dig up any actual, confirmed, peer-reviewed reports of this event. And we just published our findings in the journal Academic Emergency Medicine. Check it out. (And also check out the accompanying editorial by spine connoisseur Mark Hauswald, who you know from “that Malaysia study.”)

I won’t spoil the results, but let me put it this way:

Despite looking across 50+ years, we found few examples.
Most of them weren’t very impressive.
Even fewer occurred in the EMS setting, and none of those were the classic, sudden event you’ve heard about.

So the next time your buddy mentions this unicorn, tell him you don’t doubt him, but that he should write it up for the journals — because it’ll be the first one, and that’s publishable.

This has been an exciting project for another reason. From start to finish, this paper was the child of two parents: the FOAM and EMS communities. Of my four co-authors, I knew three of them exclusively through the web, and have only met two, yet we share interests and passions enough to collaborate on a project that took us over a year. Moreover, every one of us is either an EMT or paramedic, most of us still working actively in the field (although in a few cases we’ve accumulated some other titles too). In fact, had this reached print a few months sooner, the fanciest initials of the lead author would be EMT-B, and that should tickle you.

So never let it be said that the nonsense in this profession is invincible, or that we can’t be the ones to exorcise it. We can fix our own problems, and if we spent more of our energy on moving forward rather than complaining, it just might happen sooner than you think.

What the Heck is a General Impression?

I’m tired of all the mumbo-jumbo.

Here’s my beef. Every medical provider, particularly those who work in the acute setting (such as prehospital medicine, critical care, or the emergency department), talks about a concept familiar to us all: the overall, gut sense of how ill a patient appears. In EMS training this is often described as the “general impression,” the “view from the door,” “big sick vs. little sick,” or other euphemisms. It’s your basic opinion of whether a patient is doing okay or not, and it’s formed within the first moments of contact.

Whatever you call it, it’s important. In fact, this one factor is often what really drives your management decisions. If a patient looks truly sick, it may not matter what the vital signs show or how the history sounds; they’re getting zipped over to the hospital with bells on. Conversely, if they look really well, it’s hard to get excited even if they complain of “12 out of 10 pain” and their pulse is 100.

Here’s the rub: everybody acts like this quality is completely impossible to describe. If you tell me the patient “looked sick” and I ask what you mean, you’ll probably wave your hands and reply that it’s ineffable; that you “had to be there”; that you know it when you see it, but that it can’t be quantified and can’t be analyzed.

If true, that would mean it can’t be taught, either. New providers would have to learn to recognize this mystical patient presentation by dint of long, hard-earned experience.

And perhaps this is true. Certainly there are other aspects of patient evaluation and management that actually are too complex to reduce to simplicities. Indeed, one of the central skills of medicine, and one that humans are uniquely equipped to perform (hence the last one that computers will take from us), is our ability to extract a diagnosis from a large number of variables by recognizing subtle patterns.

But I doubt that’s true here. Why? Because you form your general impression within the first moments you meet a patient. There just aren’t very many factors that can come into play, because you haven’t obtained much information yet. The view from the door isn’t going to include ECG findings or subtleties of the OPQRST.

So I have a theory, and here it is. The entire mythical gestalt of your general impression actually involves only three things: the patient’s behavior, their breathing, and the appearance of their skin.

Behavior

The first thing you notice when you meet a person is their behavior. This mostly means two things: their mental status and their level of distress.

A sick patient may be unconscious, or visibly lethargic; healthy people are awake and alert, because the brain is one of the last things the body allows to shut down. They’re also not obviously loopy, such as profoundly confused or combative, unless they have a chronic condition such as dementia.

And if sick people aren’t so sick they can’t complain at all, then their complaints reflect their acuity. They scream, they moan, they are visibly distressed by pain or fear. They say things like they’re dying or can’t breathe or can’t see or can’t move.

Some interpretation is needed here, because appropriate behavior can depend on the circumstances. Malingerers may say they can’t breathe when they clearly can. Panic attacks may present with greater distress than the physiology warrants. A child is most reassuring when grabbing at your stethoscope and stealing your gauze. And an infant may be normal when he cries vigorously and sick when he sits in silence. But it all comes down to how the patient is behaving.

Breathing

The patient’s breathing can be evaluated from across a parking lot. You can’t auscultate or measure their oxygen saturation, but you can get a general idea.

Are they breathing at all? Are they laboring, wheezing, gasping agonally, gurgling through pulmonary edema? Are they chatting easily with the firefighters, or is sucking down air the sole focus of their attention?

Skin

Skin appearance is an idiot-proof and instantly recognizable finding.

The most common sick skins involve pallor and diaphoresis. Shocky or otherwise sympathetically-charged patients are starkly white and sweating like they’re in a sauna. It’s one of the most characteristic appearances of acute illness.

Cyanosis is next up. “Shortness of breath” in a patient who’s pink, warm, and dry is one thing, but it’s quite another when they’re turning blue.

Less common findings include the red-hot skin of fever, the yellow skin of severe jaundice, the dry skin of dehydration, and the dependent lividity of the very dead.

That’s all, folks

When you talk about a patient who looks sick, or “doesn’t feel right,” or has some other nebulous problem like being “toxic,” you’re not tapping into some vast, indescribable vault of clinical judgment. All you’re doing is using shorthand that refers to the patient’s behavior, breathing, and skin. (Notice how these factors are emphasized in our initial assessment.)

A gut belief that a patient has a big problem after a full work-up (including an H&P and diagnostics) is a different phenomenon, and suggests that your intuitive side is recognizing a larger pattern that your conscious self hasn’t yet been able to label. But that’s a distinct process from the instantaneous triage you perform when you first walk into a room.

There may be exceptional cases where something different sets off your alarm bells. But I bet most of the time, it can still be linked back to one of these three categories. (An example might be the frequent flier, well-known to you, who is usually stoic but today seems worried and wants transport. That’s a discrepancy in their behavior, ain’t it?)

Don’t believe me? Just think of how you tell the stories of your sick patients. I’ll bet you say things like, “I walk in, and he’s bent over gasping; his skin is completely soaked and looks whiter than copier paper.” Those are the factors that we recognize as important, and that’s why they’re so vividly evocative. They’re the colors we use to paint the picture of badness.

I may raise some ire by dismissing the voodoo surrounding the clinical gestalt, but here’s my challenge: if you believe there’s more behind your general impression of “sick or not sick,” then reply in the comments and tell me what it is. Maybe I’m missing or forgetting something. Maybe I’m doing it wrong and you’re doing it right. But if you can’t point to what’s missing, then I’m betting there’s nothing more to it after all.

The Long-term Care Ombudsman: Advocates on Call

Although we like to talk around here about exciting topics like shock and airway management, the reality is that for many EMS providers — particularly at the BLS level — a large part of this job isn’t stabilizing emergencies. It’s routine work like dialysis trips and stable transfers from nursing facilities. Some folks find this stuff dull, and it can be dull, but the best way to make it interesting is to approach it just like the exciting stuff and try to be excellent at both aspects of the job.

How can you excel at bringing Mr. Smith to his third doctor’s appointment this week? You can learn to be a really good patient advocate on his behalf, something that almost all residents of long-term care facilities need. We’re well-positioned to fill this role because we have a one-on-one relationship with our patients. Unfortunately, we often lack the know-how and leverage to resolve most of their problems.

Our feature in the August 2014 issue of EMS World talks about how to use the ubiquitous Long-Term Care Ombudsman program to help. It’s easy, it works, and even if you didn’t know about it, there’s one available in your area. Give it a read and think about bringing it to bear the next time the guy on your stretcher has something to say!

Murder by Checklist

Reader Steve Carroll passed along this recent case report from the Annals of Emergency Medicine.

It’s behind a paywall, so let’s summarize.

What happened

A young adult male was shot three times — right lower quadrant, left flank, and proximal right thigh. Both internal and external bleeding were severe. A ~~physician bystander~~* tried to control it with direct pressure, to no avail.

With two hands and a lot of force, however (he weighed over 200 pounds), he was able to hold continuous, direct pressure to the upper abdomen, tamponading the aorta proximal to all three wounds.

Bleeding was arrested and the patient regained consciousness as long as compression was held. The bystander tried to pass the job off to another, smaller person, who was unable to provide adequate pressure.

When the scene was secured and paramedics arrived, they took over the task of aortic compression. But every time they interrupted pressure to move him to the stretcher or into the ambulance, the patient lost consciousness again. Finally en route, “it was abandoned to obtain vital signs, intravenous access, and a cervical collar.”

The result?

Within minutes, the patient again bled externally and became unresponsive. Four minutes into the 9-minute transfer, he had a pulseless electrical activity cardiac arrest, presumed a result of severe hypovolemia. Advanced cardiac life support resuscitation was initiated and continued for the remaining 5-minute transfer to the ED.

The patient did not survive.

When the cookbook goes bad

The idea of aortic compression is fascinating, but I don’t think it’s the most important lesson to this story.

Much has been said about the drawbacks of rigidly prescriptive protocol-based practice in EMS. But one could argue that our standard teachings allow for you to defer interventions like IV access if you’re caught up preventing hemorrhage. Like they say, sometimes you never get past the ABCs.

The problem here is not necessarily the protocols or the training. It’s the culture. And it’s not just us, because you see similar behavior in the hospital and in other domains.

It’s the idea that certain things just need to be done, regardless of their appropriateness for the patient. It’s the idea that certain patients come with a checklist of actions that need to be dealt with before you arrive at the ED. Doesn’t matter when. Doesn’t matter if they matter.

It’s this reasoning: “If I deliver a trauma patient without a collar, vital signs, and two large-bore IVs, the ER is going to tear me a new one.”

In other words, if you don’t get through the checklist, that’s your fault. But if the patient dies, that’s nobody’s fault.

From the outside, this doesn’t make much sense, because it has nothing to do with the patient’s pathology and what might help them. It has everything to do with the relationship between the paramedic and the ER, or the paramedic and the CQI staff, or the paramedic and the regional medical direction.

Because we work alone out there, without anybody directly overseeing our practice, the only time our actions are judged is when we drop off the patient. Which has led many of us to prioritize the appearance of “the package.” Not the care we deliver on scene or en route. Just the way things look when we arrive.

That’s why crews have idled in ED ambulance bays trying over and over to “get the tube” before unloading. That’s why we’ve had patients walk to the ambulance, climb inside, and sit down, only to be strapped down to a board.

And that’s why we’ve let people bleed to death while we record their blood pressure and needle a vein.

It’s okay to do our ritual checklist-driven dance for the routine patients, because that’s what checklists are for; all the little things that seem like a good idea when there’s time and resources to achieve them. But there’s something deeply wrong when you turn away from something critical — something lifesaving — something that actually helps — in order to achieve some bullshit that doesn’t matter one bit.

If you stop tamponading a wound to place a cervical collar, that cervical collar killed the patient. If you stop chest compressions to intubate, that tube killed the patient. If you delay transport in penetrating trauma to find an IV, that IV killed the patient.

No, let’s be honest. If you do those things, you killed the patient.

Do what actually matters for the patient in front of you. Nobody will ever criticize you for it, and if they do, they are not someone whose criticism should bother you. The only thing that should bother you is killing people while you finish your checklist.

* Correction: the bystander who intervened was not a physician, but “MD” (Matthew Douma), the lead author, who is an RN. — Editor, 7/22/14

Toastmasters for Trauma Patients

Almost everybody in healthcare has to occasionally deliver verbal reports to their colleagues or counterparts, and almost everybody starts out bad at it. It’s a weird skill and one that takes practice, even though all you’re doing is describing what the deal is with a certain sick person.

Here’s a little walk-through discussing one important aspect of a good verbal report — a clear, coherent structure of tone, cadence, and body language that gives your words “shape.” You shouldn’t sound like a robot, because robots are hard to understand. Be Martin Luther King Jr; that’s a man who knew how to make himself heard.

We’ll be practicing with the hand-off report Sam gave to University Hospital on the Mystic St and Beverly Rd call.

A Saving People Thing

This isn’t a criticism, Harry! But you do… sort of… I mean — don’t you think you’ve got a bit of a — a — saving people thing?

Harry Potter and the Order of the Phoenix, JK Rowling

In a few weeks, I will be leaving the ambulance indefinitely.

I’m moving a couple states away to return to school, a Physician Assistant program that begins in June. And while I hope to try and work an occasional shift with a more local service, it remains to be seen whether that will be possible. So I’m now approaching a crossroads where, after approximately four years of wearing a patch on my shoulder (many different patches, to be sure), I might soon be giving it up forever.

It’s a strange sensation. It’s been pointed out that, unlike other professions — butcher and baker and candle-stick maker — EMS has a unique ability to dominate the lives of its men and women. How many doctors and nurses do you see with bumper stickers, tattoos, and T-shirts proudly advertising their trade? For many of us, you don’t work as an EMT or a paramedic, you are one; it’s part of our identity. (That’s why it can be so devastating when, through life or injury or the whimsy of employment, we suddenly find ourselves without a uniform to wear — many of us don’t know what to replace it with.) There are prominent physicians of many years who still include “NREMT-P” among their credentials. That’s like an attorney listing his high school oyster-shucking job on his CV.

There are probably many reasons for this. Buckman has observed that becoming an EMT is one of the fastest and easiest routes to “feeling important” — one quick class, and you can break traffic laws and tell everyone you’re a lifesaver. We like that, I’m sure. There’s a lot of ego in this business.

But I suspect that it also attracts people who embrace its fundamental nature. At the bottom, this job is about going to people in distress and helping them. And there is something in us — I think in everyone, although stronger in some — that wants to do that. It resonates with us as humans. (Of course, many other things resonate with humans, including sex and bacon and a great parking spot. But that’s all right. We’re complex creatures.)

The point is, this business allows us to play that role in a unique way. I believe that someday I may enjoy sitting in an office and treating patients who walk in the door, or waiting in an emergency department, or roaming a hospital floor. But that’s different; you are the all-knowing Man on the Mountain, and your patients come and form a line to beg for your wisdom. On the ambulance, people call for help, and we go to them. We take the trouble; we’re the humble servant. Yes, they have to ask, but once they do, we bring the noise, we say: “There, there. We’re here now. Everything’s going to be all right.” In the simplest, most fundamental template of this job, people have problems and they call us; we hear the call and we drive toward them; we walk into their home or business or any of the places that people go; we see a human being in distress; and we kneel beside them and ask, “How can I help?”

By coming to people in their time of need, we get closer to the heart of it all. By our willingness to kneel, we open ourselves for the dying eight-year-old to ask: “Mrs. Nurse, will you hold my hand? I’ve never died before and I’m scared.” And that’s special, and it’s not such a bad thing to elevate it, even though — as Thom Dick reminds us — no matter how much we love it, it won’t love us back.

No matter where I go from here, for me, EMS will always be about that feeling of kneeling beside someone. Or the experience of sitting on the ambulance bench, alone, just my own thoughts and a trusting and vulnerable patient.

That moment when I walk into the room, and all eyes turn to me.

The mental perk-up as the radio crackles, and the extra acuity that dials in as I recognize my call sign and my gears start turning.

Opening my mouth to give a report to a trauma bay filled with nameless people wearing scrubs.

Holding an old lady’s hand as we bounce down the road.

Touching a shoulder as I say good-bye.

Iced coffee from Dunkin’ Donuts, titrated to my tiredness.

The smell, sound, and non-stop rumbling of a diesel engine.

Black shoe polish.

Sitting beside a partner and feeling like it’s the two of us against the world.

There’s a lot that’s wrong with this job. But there’s something that’s right about it, too, and it’s something important. And that’s why we keep coming back.

I’ll be busy soon, and this site will have to take a back burner. Updates will come less frequently, and I can’t guarantee new scenarios or new posts or new Library material on any reliable schedule. But wherever I end up, I don’t plan to turn my back on it. Because even if you leave the ambulance, I’m not sure if you ever stop being an EMT.

Super Soakers: Building a BLS Irrigation Device

Advanced CPR Techniques for Basic Providers

So you’re an EMT operating at the BLS level, and you understand that when it comes to cardiac arrest, you’re the man. Sure, you’ll call for the medics if you get there first, but the stuff that’s really important — compressions and defibrillation — well, that’s right in your wheelhouse.

But it may seem a little simple. Simple is beautiful, but maybe you’re wondering what else you can do to really master the art of resuscitation, especially when you’re out there on your own. Take it up a notch, if you will. And a lot of the cool stuff that’s being tried in the big world, such as pit-crew choreography and various supportive devices, are only available if your service makes a large-scale decision to adopt them. What can you do as an individual provider to absolutely ensure your peri-dead patients have the best chance of survival?

Here are some ideas.

Don’t Stop Compressions, at All, Ever — Seriously, Just Don’t

Hopefully at this point you don’t need to be convinced that stopping compressions is a bad thing. It truly is. The mountain of evidence is unequivocal: any time spent not-compressing kills people; each interruption in compressions kills people; pausing after compressions before defibrillating kills people; pausing after defibrillating and before resuming compressions also probably kills people; and so forth.

The trouble is that, despite this knowledge, we still stop all the goddamned time. There’s a lot going on during a code, and a lot of things you might want to pause for. But let’s go through a few and see if we really have to stop:

Stop for Pad Application?

As soon as you found the patient, you began compressions, right? As long as they weren’t wearing a honking seal-skin anorak, you can do that just fine over a shirt, blouse, or other light garment. (Hint: anoraks and similar loose outerwear can often just be pulled off the arms overhead, like removing a T-shirt.) Bam, in you went.

Now your partner needs to apply AED pads, though. Should you stop what you’re doing? Heavens, no. Let him work around you if he needs. He can unzip, rip, cut around your hands, tug the fabric out from under them as pressure lifts between compressions, and clear as much of the chest as he needs. Then he can simply apply the pads. No interruptions, no problem.

In some cases, a CPR-feedback device will be present, either combined with the pads as a one-piece unit, or as a separate “puck.” Either way this usually needs to go between hands and chest, but you should be able to slip it under there with (at most) a brief hiccup in the rhythm

Stop for Rhythm Analysis?

Unfortunately, if you’re using an AED (rather than a manual monitor like the medics are toting), you will need to stop compressing and come off the chest in order for the device to analyze the rhythm. Otherwise, the electrical motion artifact produced will confuse the computer. So as soon as the device tells you to stop compressions for analysis, clear the body — but don’t go far (in fact, I would simply hover), and as soon as it’s finished, get back on there.

You may need to stop for manual rhythm analysis as well, but some monitors have a filter that can allow the medics to “read through” compression artifact.

Stop while Charging?

So the AED finished analyzing and advised a shock; now it’s charging. Can you compress during this period? Yes. Both common sense (it won’t shock unless someone pushes the button, so… don’t push the button) and at least one study (albeit for manual, not automated defibrillators) have shown this to be safe. There are some AEDs that will get confused if you compress during this time, so know your gear. [Edit: per our “para-engineer” friend Christopher Watford, the Philips FR2+, FRx, and FR3 AED models, plus the Zoll AEDPlus and AED Pro, may complain and possibly halt if you try to compress while charging or shocking. Lifepak AEDs should be mostly okay. Chris and David Baumrind — two of the conspirators behind EMS 12-Lead — wrote a feature for JEMS discussing the behavior of various AEDs if you attempt these maneuvers. Required reading!]

Once the device has charged and is ready to shock, clear everybody except the compressor, ensure that they’re clear, and coordinate between the compressor and button-pressor. Something like, “I’m going to count to three, and when I say three, I’m going to come off and you’re going to press shock, okay? One — two — [come obviously clear] and shock — aaand back on.” The actual defibrillatory shock takes a fraction of a second, and the device will verbally announce once it’s delivered, so you can get back on the chest almost immediately after pressing “shock.” There is no residual “charge,” it doesn’t “take a while” to deliver, it’s a quick blip, so you’ll only need to clear the chest for a moment — no more.

Stop while Shocking?

As a matter of fact, do we need to clear the chest to shock at all, or can we keep our hands down, compressing continuously while the electrons flow?

Instinctively, most of us say “No thanks!” However, a little logic suggests the risk may be low. Electricity follows the path of least resistance, and if pads are properly placed and well-adhered to the chest, this path should always be through the patient’s chest. The alternate path up into your hands is much longer, and will only exist at all if you have a connection to the ground, which (if present at all) will probably run through fabric and other insulators. Since almost all AEDs now are biphasic — these use less current than the old monophasic devices — and since pretty much everybody wears rubber gloves while they compress, risk is probably quite small.

The evidence supports this somewhat. Consider these studies: Lloyd, Neumann, Sullivan (supports multiple-gloving in my view), Yu, and Kerber.

This idea has been gradually gaining traction, and some folks have already started doing it routinely, mostly of their own volition. Salt Lake City Fire has even been experimenting with making it a standard option during all resuscitations. For the most part, the worst adverse effect reported seems to be a tingling sensation, particularly if there’s a tear in your gloves. It’s reasonable to ensure that you’re wearing intact gloves, especially over prolonged efforts (multiple shocks may break down the material), and probably wise to double- (or triple-) glove. If there’s a feedback device between your hands and the chest the risk is even lower (or you could lay something like a rubberized blanket over the chest to totally insulate yourself, as in the Yu study).

Now, everybody has a story about a guy who knows a guy whose ex-partner’s bartender was touching a patient during defibrillation, got blown across the room and set on fire, and now can’t pronounce vowels. For the most part, this seems to be purely legend. The trouble is that there isn’t sufficient evidence yet proving it’s safe to make this an official practice on a top-down level; but that doesn’t mean you can’t make the decision for yourself.

If you have an arrhythmia (especially with an ICD or pacemaker), or another legitimate reason to be concerned about your own heart, it’s probably reasonable to pass. For everybody else, to paraphrase Dr. Youngquist of SLC Fire, this practice is probably safe for providers — if not yet for administrators. So you might not see this in your protocols for a little while, but I’ll bet it doesn’t say not to do it, either. The decision is yours.

(There is a possibility that some AEDs, particularly those with feedback technology, may detect the ongoing compressions and refuse to deliver a shock. Again, see above for more info.)

Stop for Ventilations?

Until you get some kind of tube into the patient’s airway, you’re going to have a hard time bagging any air in unless you pause compressions first. One option would be to simply skip it and perform continuous compressions, which is very reasonable, especially early in the code, or really whenever in doubt. But if you do pause to ventilate, take as little time as possible — pause, breathe goes in, exhale, second breath, and then immediately back into compressions (no need to wait for the second exhalation).

Go Faster — and Probably Harder

The currently recommended rate for chest compressions is “at least 100 per minute.” In other words, that’s not a target, that’s a minimum. Can you go too fast? Probably, but it’s hard, and it’s much easier to go too slow.

There’s an accumulating body of evidence, however, that points toward a more exact rate — right around 120/minute. Up to that number, more people survive if you push faster; above that number, fewer survive. It’s not for-sure yet, but in this business, not much is totally sure.

Since it fits the official “over 100” recommendation anyway, I now use 120 as my target rate, and I think you should too. It does mean that your old go-to songs for musical pacing, such as Stayin’ Alive (or perhaps Another One Bites the Dust) won’t work anymore, since those are matched to 100/minute beats. But 120/minute is simply twice per second, and most people can approximate that pretty well, or you can find a faster song (try this app for suggestions).

With that done, are you pushing hard enough? The recommendations are at least two inches deep in adults, so you should at least be hitting that. (It’s deeper than you think.) But as much as some people are willing to go wild on the rate, few people ever seem to challenge the depth. Unless you are an 800-lb gorilla and the patient a 70-lb granny, you are unlikely to cause meaningful damage, and there is a direct link between depth of compressions and cardiac output. Try to really aim for the mattress, and whatever depth you’re hitting, even if you think it’s pretty good, go a little deeper.

The Knuckle Hinge

Does it matter how you hold your hands against the chest? Maybe.

What really matters is that you provide good compressions, but hand position can affect that. What you should do is find a CPR mannequin and experiment until you figure out what works best for you. But while you’re experimenting, here’s something to try.

Most people lay one palm over the back of their other hand, and either interlace their fingers (as the AHA videos usually depict) or don’t (I don’t, since I find it somewhat awkward, but since it forces your arms to externally rotate, it can help encourage providers to lock their elbows). Either way, as you meet the chest, you’ll be making contact with the heel of a palm and one set of knuckles.

“Glue” these knuckles to the chest; they don’t move, so once you’ve found your position, you’re locked-in. But each time you compress, do allow your palm to lift off the chest, “hinging” at the knuckles as they remain in contact. Don’t come up very far — just enough that you could slip a sheet of paper between palm and chest — but get a little daylight in there.

What’s the point? One of the more common errors when otherwise high-quality compressions are performed is a failure to allow the chest to fully recoil. You can go deep, but if you don’t come all the way up at the top, you’re still not producing the largest possible stroke. What’s more, unlike poor depth, this isn’t always obvious by looking at the chest (either to you or to others), so the safest method to ensure full recoil is to actually lift off the chest. If you remove your hands completely, though, you tend to lose your place, and your hands can “wander” until you’re pushing on the patient’s feet or your partner’s face. The knuckle hinge allows the best of both worlds.

Assign a Monitor

Isn’t this tiring? Now you’re pumping away crazy deep, twice a second, full recoil, and not stopping for almost anything.

Even if you’re an Olympic decathlete, this will start to wear you out fairly quickly. You’re full of adrenaline, and you’re a rockstar lifesaver, so you won’t say anything, and perhaps you won’t even notice; you’ll keep plugging away. But before long, you won’t be pushing quite as hard or deep, or quite as fast, or maybe you’ll start leaning on the chest instead of recoiling all the way. I promise you will; many studies have shown this; and what’s more, you’ll probably still think you’re doing good work.

No problem. As long as we have adequate manpower (and in most places, there are plenty of people on scene at a code), simply assign one person to monitor the quality of compressions. If it’s you, your sole job is to sit somewhere with your head close to the action, staring at the up-and-down, and ensuring it follows all the criteria we’ve discussed. If it needs to be faster, you tell them to speed up until they’re on pace. If it needs to be deeper, tell them. If they ever pause for any unnecessary reason, yell at them like an Italian grandmother until they start back up. And once it’s clear that they’re fatiguing, you make them swap out, and ensure that the swap happens with minimal delay. The AHA recommends switching every two minutes, but use a smart approach; some compressors will last less, some more, and if you reach a mandatory pause (for rhythm analysis, say), you might as well change even if the current person has some juice left.

Depending on resources, they may be swapping with you, or there may be enough people sitting around that you can have a rotating pool of dedicated compressors. You can maintain the same person as monitor (the easiest method, if you can spare them), or just have each on-deck compressor act as monitor.

Useful tools for the monitor include a watch with chronograph, but even better would be a metronome. That way you can set up an audible pace (120/minute, remember) that any monkey can follow. A few services do carry actual digital metronomes, but if not, most smartphones have metronome apps available. (Find and download it now, not in the patient’s living room.) You can also throw an MP3 from an appropriately-paced song onto your phone, if nobody minds running a code to a soundtrack (probably not ideal when there’s an audience). The monitor person can keep track of other times as well, such as the ventilatory rate once an advanced airway is placed, total duration of the code, times of medication administration, and so forth. A pad of paper or strip of tape down the leg are helpful.

An electronic feedback device is a helpful adjunct to this role, and if resources are limited can replace it, but it’s not quite the same. If it is available, tracking the automatic feedback (and ensuring the compressor obeys) is the monitor’s job.

Whether or not a monitor is assigned, everybody performing compressions (really everybody at the scene) should understand that it’s still their responsibility to ensure quality. This is particularly important when it comes to eliminating interruptions, because even if there’s somebody to yell at the compressor when he stops, if he’s stopping all the time that’s still a lot of pauses. An effort should be made when assigning a compressor (who isn’t you), such as a first responder or bystander, to make them understand that they “own” their compressions, and it’s their responsibility to do ’em right and stop for nothing. The monitor’s job? Just to keep them honest.

Ask Why

Cardiac arrest happens for a reason, and even though it’s the most time-sensitive, treat-the-ABCs syndrome that exists, there are still times when you’ll never fix the problem without understanding the cause.

In a perfect world, you’d show up, compress, apply AED, shock, get a pulse, the patient sits up and hugs you, you transport and all’s well. In a realistic world (depending on your area), usually ALS shows up at some point and things take a more technical direction. But if you’re working the arrest for more than a couple minutes, have adequate manpower, but are still BLS-only, then your extra providers shouldn’t be sitting around twiddling their thumbs; they should be gathering information, planning the next step, and preparing for transport.

Ideally, one person is running the code. Either that person or somebody competent he delegates to should communicate with family or bystanders, examine available records, dig through the meds, whatever — try to determine both the history of the present event, and a reasonably-complete past medical history and medication list. Partly, this is for later management; the medics or the ED may need it. But it’s for you, too, because it may suggest your course of care.

Without an ECG, you haven’t got much to tell you what’s happening, except that the patient’s got no pulse. (Auscultating the chest may indicate whether a regular heart rhythm is present which is simply not perfusing — PEA, or if you’re a magician you may be able to “hear” V-tach — but you have to stop compressions to appreciate much.) You’re unlikely to be able to magically predict whether you’re dealing with V-fib versus torsades versus asystole. But you may be able to guess that certain correctable causes are present.

For instance, was the patient complaining of classic MI symptoms (crushing chest pain, nausea and vomiting, dyspnea) for twenty minutes before he finally became unresponsive? And he’s had two heart attacks before, with several stents placed? It’s a fair bet that he’s had another, which caused this arrest, and you may not have much luck getting him back until that artery can be opened back up. You can and should still work him initially on scene, but your mental goal should be delivering him to a PCI-capable hospital, so while you do your thing, stay on that track. If you get a few “no shock advised” messages with no pulse, or perhaps shock once or twice but he remains severely unstable, try to get him packaged as you continue your awesome compressions, notify the hospital of the situation and your suspicions, and get him over there. Try for ALS, who can perform a 12-lead ECG, which will facilitate this process (and your protocol may not permit you to divert to a more-distant PCI hospital otherwise).

Do you have reason to suspect hypovolemia as the cause of arrest? Is there obvious external bleeding… or is there a rigid and distended abdomen, perhaps with a story of abdominal pain or blunt trauma? In that case, you can push or shock all you want; you’re not going to refill an empty pump. Maybe chest trauma with a potential tension pneumothorax or cardiac tamponade? Transport ASAP to a trauma center (and perhaps ALS, since they can decompress a pneumo and give some volume if appropriate).

Is this a hemodialysis patient who missed two sessions, has been lethargic and sick-appearing, poorly-tolerating exercise, and finally fell asleep and didn’t wake up? Suspect hyperkalemia, a true “ALS-curable” condition, so if medics are available, work it until they arrive. If they’re on the dark side of the moon, transport with the best compressions you can manage.

Is the patient a known diabetic, taking insulin, and a story consistent with hypoglycemia? Check that sugar if you can, and if it’s something perverse like 7 mg/dl, get them to either ALS or an ER — both can administer intravenous sugar.

Could it be a hypoxic arrest? All arrests are hypoxic after a few minutes — dead people don’t breathe — which is why it’s usually reasonable to breathe for them (although far from a top priority). But if you walk in to find a post-drowning victim, or a hysterical mother saying her child choked and now has no pulse, you may have a cardiac arrest whose underlying cause is nothing more than hypoxia: their heart didn’t get enough oxygen, so eventually it gave up too. They still need compressions, and may need to be shocked, but most of all they need oxygen, so opening the airway and bagging in high-concentration O2 is a top priority. (Compare this against the post-MI patient above, who doesn’t need any oxygen at all until you have enough hands to provide it without delaying compressions and AED use, and even then doesn’t need much.)

Possible pulmonary embolism? Poisoning? Commotio cordis? The list goes on. The point is, if you have the resources to take a moment, gather some information, step back, and think, you can often do a pretty good job of guessing what brought you here, even without the benefits of the ECG. In some areas, your policies and protocols will dictate pretty clearly what decisions you can make, and it may not matter much. But flip through that rulebook now, because often times people assume it says more than it does (for instance, “closest appropriate facility” is more common than “closest facility”). When in doubt, you can always call medical control and make your case.

(As a general point of safety: continuing CPR while packaging and transporting emergently is difficult at best, and both unsafe and low-quality at worst. This should factor into your decision-making, as should the specific obstacles presented by extrication, and the potential availability of a mechanical compression device, which can make the process substantially easier.)

Just don’t ever try to argue that only ALS is allowed to think.

BLS is all yours, and cardiac arrest remains a fundamentally BLS problem. Own it.

Staying in Place: Compensation and Endpoints

Man’s leaning against a wall. He doesn’t move for hours. Just stands there not moving. Finally, someone says, “You been here all day — don’t you have anything to do?”

“I’m doing it,” he answers.

“Doing what?”

“Holding up the wall.”

And who’s to say he’s not? Maybe he’s working as hard as he can to make sure that wall doesn’t fall down.

In this situation, the man is a compensating mechanism. He is struggling to prevent changes in the wall; keeping that wall upright is an endpoint he cares to maintain, to sustain, to keep intact.

How do we know that the wall isn’t holding up the man? Because we don’t care about the man. Whether he leans or falls doesn’t matter much to anybody. But it would be a terrible thing if the wall collapsed. So we’ll let the man lean or shift in order to prop up the wall when it starts to totter — we’ll use him, adjust him, to compensate for any wall-changes. That’s why he’s there.

If the wall gets weak enough or tilts too far, though, he won’t be able to keep it up. He’ll try, but he’s not infinitely strong, and then maybe the wall begins to tilt or collapses completely. Since we know that under normal circumstances, he’s doing his best to prevent this, if we walk in and see that the wall is tilting, that is not a good sign. It may mean that despite his best efforts, the man has exhausted his strength and is no longer able to resist further wall-changes; or it may mean that, for some reason, the man isn’t doing his job properly. Either way, any further tilting will be unopposed, and will probably happen rapidly and uncontrollably.

Compensators and endpoints

This same dynamic plays out within the human body. As we know, living organisms seek to maintain a certain homeostatic equilibrium. We put our vital metabolic processes in motion and we don’t want them to halt or change, despite any insults or fluctuations imposed upon us by our surrounding environment. So our bodies struggle to keep all of our complex systems at an even keel, using a diverse and powerful array of knobs, dials, and other regulatory tools. Not too hot or too cool, not too acid or too basic, not too fast or too slow. Just right.

The kicker is this, however. Some of our physical parameters are more important than others. In other words, while some parameters have room to adjust, others aren’t negotiable, can’t change much, without derailing our basic ability to function and survive. Things like blood pressure (or at least tissue perfusion, for which blood pressure is a pretty good surrogate measure) are essential to life; your pressure can fluctuate a little, but if it drops too low, you are unquestionably going to suffer organ damage and then die. And yet there are many insults that could potentially lower our blood pressure if we let them: if we bleed a little, or pee a little, or don’t drink enough water, or sweat, or even just stand up instead of sitting down. How do we preserve this vital parameter despite such influences?

By compensating, of course. Our body gladly modulates certain processes in order to preserve other, more important parameters. So in order to maintain blood pressure, perhaps we accelerate our heartrate. In an ideal world, it might be nice if the heart were thumping along at — let’s say — a mellow 80 beats per minute. It’ll use little less energy and less oxygen than if it were beating faster. But it’s really important to keep our blood pressure up, and speeding up the heart can increase the pressure, so we gladly make that trade and induce tachycardia. (Many of these compensatory systems are linked to the sympathetic nervous system, our body’s standard “all hands on deck” response to stress and crisis.)

So imagine we find a patient who’s bleeding and notice that he’s tachycardic, with a normal blood pressure. This suggests a compensated shock; the body is using tachycardia to maintain that normal pressure we see; although his volume is lower than usual, the critical endpoint of adequate blood pressure is still intact.

But what if instead, we found him tachycardic and hypotensive? Well, that’s not good. We see that the body is trying to compensate, but we also see that the important endpoint — blood pressure — is falling nonetheless. The body would never intentionally allow that; BP is too important. So we recognize this as decompensated shock. The hypovolemia has progressed so far, and volume is now so low, that he can’t make up the difference anymore — the compensatory slack has run out — and any further decreases in volume will probably lead to an immediate and unopposed drop in pressure. There’s nothing more the body can do on its own; it’s out of rope.

The skilled clinician — or “homeostatic technician” as Jeff Guy says — uses this predictable progression to understand what’s happening in almost any crisis. Because primary insults are initially covered up by compensatory mechanisms, they may not be immediately apparent, and the earliest and most detectable signs of physical insult are usually nothing more than the footprints of the answering compensation. Thus, when when we encounter those, we know to suspect the underlying problem even if it’s not obvious yet. It’s like seeing brakelights flash from cars on the road ahead; even if you can’t see an obstacle yet, you know people are slowing down for something.

Obvious signs of decompensation usually show up late. Once the primary, underlying problem is revealed by failure of the corrective mechanisms, it’s often progressed so far that it’s too late to address. If you wait to brake until you can see the wreck itself, you might not be able to stop in time.

Two signposts for decompensation

There are two great ways to recognize which signs and symptoms connote decompensation.

The first is to understand which physical parameters are endpoints — which functions the body tries to preserve at all costs. These processes are only compromised as a last resort, so if you see them deteriorate, things are in the end-game; the body doesn’t intentionally sacrifice these for the benefit of anything else.

The second clue is more subtle. In this case, you observe a compensatory mechanism (not an endpoint), but find that it’s no longer successfully compensating — it’s failing, and starting to unwind and scale back, rather than doing its job. The changes in the compensatory system are inappropriate, resulting in less of what we need, not more. This happens when our systems are so damaged that they can’t even fix problems and pursue homeostasis anymore; our infrastructure, maintenance, and repair systems are breaking down. Consider this: we saw how tachycardia could be compensatory, but could bradycardia ever be beneficial in shock? Probably not. So if we found a shocked patient with bradycardia (and likely hypotension, the failing endpoint), we should be very alarmed indeed. There’s nothing helpful, compensatory, or beneficial about bradycardia in the setting of shock, so we recognize that the body would never go there on purpose. It’ll only happen when the machinery itself is falling apart.

Consider, for instance, Cushing’s Triad, the collection of signs often encountered after severe traumatic brain injury, when intracranial pressure has increased enough to squeeze the brain out from the skull like toothpaste. The triad includes hypertension, bradycardia, and irregular or slow respirations. What’s interesting is that, while all are a result of increased ICP, one of these is compensatory, while the others are merely the result of damage. Hypertension is the body’s compensatory attempt to force blood into the brain despite the elevated pressure in the skull. But bradycardia and bradypnea simply result from pressure upon the regulatory centers of the brain tasked with maintaining breathing and heart-rate. That’s why hypertension may be seen earlier, while the other two signs won’t usually manifest until the brain is actively herniating. One signals compensation, the other two decompensation.

Of course, there can be other reasons why compensatory mechanisms might fail, or at least exhibit lackluster performance. Some medications or other aspects of a medical history (potentially unrelated to the current complaint) might throw a wrench in the system. For instance, beta blockers (such as metoprolol and other -olol drugs) limit heart-rate as part of their basic mechanism, so patients with beta blockade often have trouble mustering compensatory tachycardia during shock states. That doesn’t mean they’re any less shocked; in fact, it means they’re more susceptible to hypotension, and that you must be especially on the lookout, because you won’t see one of the red flags (a rapid heart-rate) you might usually expect. Elderly patients with many comorbidities are generally not able to muster up effective compensation for anything, so they can deteriorate quickly, and without much fanfare. Ironically, healthy pediatric patients are the opposite: since they’re so “springy” and smoothly functioning, they compensate very well, with few changes in observable endpoints, until suddenly running out of slack and crashing hard because they’re already so far from shore.

Here are a few important compensatory signs, breakdowns of compensatory systems, and vital physical endpoints:

Appropriate signs of compensation

Tachycardia — increases cardiac output
Vasoconstriction (cool, pale skin) — raises blood pressure
Diaphoresis (sweatiness) — decreases temperature when necessary, but is often just a side effect of sympathetic stimulation
Tachypnea — increases oxygenation, CO2 blowoff, and cardiac preload
Fever — part of the immune system’s response to infection
Shivering — warms a hypothermic body

Inappropriate changes in compensatory mechanisms

Bradycardia — reduces cardiac output, rarely useful in illness; as a chronic finding may be the result of high levels of cardiovascular fitness (in healthy young patients) or medications (in sick old patients); but acutely, it is an ominous finding
Bradypnea — reduces oxygenation, CO2 blowoff, and cardiac preload
Hypothermia (or normothermia when a fever is expected) — suggests a failure of temperature regulation

Inviolable endpoints

Blood pressure — can elevate in stress states, but should not drop below resting levels
Mental status — except in the presence of a drug or similar agent directly affecting cognition, maintaining appropriate alertness and mentation are always a top priority for the body
Blood glucose — kept at normal levels in almost all situations, except when the regulatory systems fail, as in diabetes mellitus
pH — most of the cellular machinery fall apart if significant acidosis or alkalosis occurs
Low O2 saturation or cyanosis — although oxygen saturation can dip briefly without harm, and in some patients (particularly those with COPD, or long-time smokers) it may run low at baseline, a significant acute drop — or the clinical equivalent, which is frank cyanosis — is always inappropriate.