Bradycardia - Traumatic etiology?

When the patient has bradycardia, you run through a short differential. Electrolytes, MI, drugs,.... trauma? How does that work?

The patient
A trauma alert was rolled into room 5 at the 'Port. A 45 year-old male, restrained driver in a roll-over, who had been ambulatory on EMS arrival. He was mildly intoxicated, denied any significant medical problems. His vitals were normal both prehospital and in the ED. (The trauma alert was due to mechanism, not his condition.) 

His exam was notable for a rather large laceration to his scalp, with a correspondingly large blood clot at the head of the backboard.

"He probably smells my dog!"

The bleeding was controlled, and the evaluation continued. 

While we were getting the chest x-ray, however, we noted that his heart rate, which had intially been around 70-80, started slowing down. 60, 50, 40, down to the 30s! 

His blood pressure, which had also been normal, plunged down to a systolic BP of around 50 mmHg. His ECG showed this:

An old ECG was entirely normal. Interestingly, the patient, in a supine position the whole time, denied any symptoms whatsoever, and was moderately amused by our concern.

Discussion
So what happened to his heart? 

Well, we should worry first about ischemia- or infarction-related bradycardia. An inferior MI is notorious for causing 1° and 2° AV blocks, most of which resolve on their own. These bradycardias manifest with a narrow QRS, since the block involves the AV node, but not the bundle of His, etc. They usually get better in a few days, on their own.

By contrast, anterior MIs may involve an infarct of part of the ventricular conduction pathways. The patient will have a wide QRS and a high-grade 2° or 3° AV block. These are bad, and need permanent pacemakers!

Although you should think of hyperkalemia when you see bradycardia, there was little else to suggest it. He denied any medications, so digoxin, beta-blockers, and calcium-channel blockers seemed unlikely, especially given how quickly the rhythm had developed after normal prehospital vital signs.

Perhsps I should be clearer about how the bleeding from the scalp was controlled. Since the wound was large, and the bleeding brisk, a number of staples were rapidly placed.

NOT an approved wound closure technique. (credit)

Let's take a closer look at the ECG. Like I said before., he gradually slowed down to 34. 

Sinus activity is almost extinguished - I can only find 2 P-waves, preceding beats #1 and #3. The QRS is narrow, suggesting a junctional rhythm, albeit much slower than you would expect (usual junctional rate is 40-60). You can't really call it complete heart block, since there is so little atrial activity; instead, it's just called AV dissociation.

Putting all this together, it appears he had a cardioinhibatory/reflex syncopal episode; i.e. he fainted. The placement of the staples likely triggered a strong vagal reflex, which inhibited both the sinus node (almost no P-waves) and the AV node (junctional bradycardia). 

Fortunately he was already supine when it occurred!

Inappropriate stapling technique.

The treatment
He got atropine 0.5 mg IV, and a liter of NS on a pressure bag. His heart rate corrected quickly, coming up to about 80, but his blood pressure took a few more minutes to come up! He was admitted, and did not have any more bradycardic episodes. 

Bottom line
 No harm, no foul, as they say. But I do think we're going to be more enthusiastic about using lidocaine in the trauma bay, however!

How do patients view our care?

Back when I worked on a rural private ambulance, a pair of EMT-B coworkers tipped a stretcher over in the hospital parking lot - with the patient on it. The patient was not seriously harmed, fortunately, aside from a huge bruise on the side of her face. 

"Right here. Not here or here so much. Right here. .."

Now, the two EMTs were petrified about the near-certain complaint, firing, and lawsuit, but the patient just brushed it off - it turns out she had a real soft spot for those "ambulance girls."

On the other hand, I also have seen patients complain about some "trivial" matter, right after receiving high-level ALS care, true life-saving stuff. 

What happens after these complaints? The EMS crew becomes discouraged, the supervisor gets an earful, and the patient tells all their friends about their "terrible care." These sorts of complaints can be very frustrating, seemingly coming out of nowhere. 

Researchers in the UK decided to tackle this issue with a novel approach, aiming to explain the disconnect between the medics intentions and the patients perceptions.

                                                              *** Spoiler alert***
  Your patients may be judging the quality of their care based on non-technical aspects.

The study

PubMed

In Patients' and ambulance service clinicians' experiences of prehospital care for acute myocardial infarction and stroke: a qualitative study, the authors carried out interviews with both patients and with "ambulance service staff." 

Researchers in this UK study chose to study patients who had been transported by the city EMS agency for a suspected MI or CVA. They also selected a groups of the "clinicians" (likely on the level of U.S. paramedics) who worked for the ambulance. In separate interviews, they asked these patients and providers various questions. (Unfortunately, they weren't able to link up the exact medic-patient pairs. That would have been difficult to arrange, I can imagine.)

So, after sifting through hours of recordings of interviews, the researchers found some interesting common ideas.

Communication
The patients placed a good deal of emphasis on how well (or badly) the medic was able to establish rapport, and explain their medical condition. The medics, for the most part, explained that they usually tried to provide reassurance and contact . Of course, a few medics explained that it wasn't their role to diagnose or explain the patient's condition to them, as "it’s up to doctors to make the ultimate diagnosis."

Pain management
This really was the only area in which the patients commented on the medical care itself. They may not know much about adenosine versus amiodarone, but they sure understand if their pain isn't acknowledged, much less treated! Of course, it proved to be a frustrating topic for the medics, as pain management often ends up near the bottom of the list of priorities during transport.

Speed
Again, patients may not know if the medic knows how to treat an MI, but they attach a good deal of importance to how quickly the ambulance arrives! Prehospital folks know this, and understand that a long response time "means that you are already on the back foot." More frustration - many patients viewed delays at ED triage as part of the EMS experience, if not precisely their fault.

Are these results expected? 
Yes & no. No one has done an academic study like this before, but that doesn't mean that people haven't been thinking about it. 

Allen Johnson, a paramedic-turned-hospital-CEO, wrote an article for JEMS back in 2010 about patient satisfaction in EMS. In The Customer's Always Right: Steps you can take to ensure customer satisfaction, he described most of the same issues that were raised in the new study. The article is not short, but I really like his summary:

Patients usually aren't qualified to evaluate the proficiency of our life-saving skills, but they are more than qualified to fully assess our interpersonal skills. And frankly, life-saving skills may be used on less than 1% of patients; our interpersonal skills are assessed 100% of the time.

A colleague once summarized the EMS patient's expectations to four simple points: 1) Get there quickly; 2) Be nice to me; 3) Tell me what you're doing, and 4) Take away my pain.

Leave it to a paramedic to boil down the research to this level!

So why do we care?
Because your bosses care. And their bosses. And regulatory agencies, Medicare, insurers,  the New York Times, as well as Yelp!

That is unlikely to be a surprise to anyone who has worked in healthcare for more than one day. In fact, large segments of the medical industry are devoted to measuring and reporting patient satisfaction, without any regard for the technical quality of the care. Everybody is being judged for patient satisfaction in medicine these day - including helicopter-EMS!

Critical (but also satisfied!) patients: Baptist LifeFlight

Money is also on the line now. Not only do emergency departments worry about patients choosing a different hospital, but they may also be payed less by Medicare if they have poor patient-satisfaction scores.

This attitude is now as dated as that nurse's cap.

Can EMS be far behind in this trend?

The bottom line
Be personable with your patient, communicate with them, and address their pain. 

Of course, you need to get that ECG, treat the hypoxia, and recheck the vitals signs. But those are, increasingly, not the only things that we are judged on these days!

STEMI called from the field - or is it?

As I have remarked before, the computer interpretation of the ECG can only go so far. Occasionally, it mistakes a benign, common finding (e.g. early repolarization) for a STEMI. Other times, it misses an atypical form of a STEMI.

And other times, the computer interpretation has the potential to mislead the clinician in a dangerous direction...

The patient
A mid-thirties male with a history of hypertension had an acute onset of chest pain while at rest. It radiated to his back, and was constant. It was non-pleuritic, constant, and had no associated dyspnea. Interestingly, he had just taken a ever-the-counter "sexual enhancement" pill (such drugs occasionally contain potent - and illegally added - active ingredients).

EMS found him to be bradycardic, and profoundly hypertensive, with a SBP of 230 mm Hg. His ECG was obtained:

Based on the symptoms and the ECG, along with the computer interpretation, EMS alerted the ED that they were bringing in a cath-lab candidate.

ED evaluation
The ED physician met EMS at the door, and called for cath-lab activation immediately. The patient was clearly in severe pain (he would eventually receive a total of 65 mg of morphine in the ED), with waves of sweat rolling off his face and chest. In addition to the severe chest pain, he also described numbness and weakness in his left leg, despite moving it as he writhed in pain on the stretcher.

An ECG was obtained in the ED:

Also a chest x-ray:

The ED physician had a brief conversation with the interventional cardiologist, who asked that the patient be started on the anti-platelet drug prasugrel while he started speeding on his way to the hospital at warp factor 9.  He had viewed an image of the EMS ECG on his smartphone, and thought that a diagnosis of STEMI was likely as well.


Question
Now, you might suspect this patient did not end up having a STEMI, or else why would I post the case?

Where, then, did the patient end up? Cath lab? ICU? "Other?"

Subsequent course
The patient's appearance was "sicker than the ECG," and suggested an alternate diagnosis. An echocardiogram suggested widening of the aortic root. An emergent CT angiogram of the chest was performed before the cath lab was ready.

The diagnosis of a type A aortic dissection, extending from the carotid arteries down to the left iliac, was made based on the CT.

Labetalol and nitroprusside were started to control his blood pressure, and the patient was taken to the OR by cardiothoracic surgery.

So, what about the ECG and the "STEMI?"
There is no prior ECG available for comparison, but the ST and T wave abnormalities found on the EMS tracing were stable during the initial hospital course. This suggests that there was no active cardiac ischemia.

Probably, the ST elevation in the anterior leads was likely a repolarization effect, secondary to left ventricular hypertrophy (LVH), a very common STEMI mimic. LVH is typically caused by chronic hypertension, a well-established risk factor for aortic dissection.

Can we use the ECG to diagnose aortic dissection?
Probably not. The diagnostic standard will remain the CT scan, given the excellent visualization.

But are there some ECG findings that could suggest aortic dissection? A recent study provides some answers.

A 2010 study looked at 159 patients with a diagnosis of dissection, and classified the ECGs they found in various ways. Most importantly, they looked at both acute and chronic changes.

Just as seen in our patient, LVH due to long-standing hypertension was fairly common, around 10%. We would expect this ECG finding to be chronic, however, and evident on prior ECGs. Curiously, this patient also had sinus bradycardia, which was seen in 11.3% of the study patients. It isn't clear what this is caused by.

What about the 8.2% of patients that had acute ST elevation? How do we avoid sending these patients to the cath lab, or giving them heparin or other anticoagulants?

First off, aortic dissection is rare, and ST elevation is overwhelmingly more likely to be due to a "true STEMI" than a dissection. Second, a dissection will typically have an abrupt onset, with "ripping" pain radiating through to the back. Since a dissection can propagate up the carotid or vertebral arteries, you can find stroke symptoms along with the chest pain. Similarly, as the dissection can extend into other arteries, there may be ischemia of the arms or legs, along with pulse deficits.

Third, dissection will infrequently cause ST segment elevation due to occlusion of a coronary artery as the dissecting layer spreads towards the aortic root.  The right coronary artery is usually taught as being the one most commonly affected, and the study supports this; over half of the patients with ST elevation had those elevations in the inferior region, supplied by the right coronary. Unfortunately, a number of other patients had left main coronary occlusions, and the ECG findings were much more variable with those.

The Bottom Line
It isn't always a straight-forward STEMI, even if the computer is telling you so!

Two interesting recent EMS calls.

I don't have a deep analysis of a recent study, or a recent change to the protocols, or even my thoughts on some EMS controversy

I do, however, have a gross picture and an interesting EKG! Both of these come from patients brought in by the same long-time medic at American Medical Response in Bridgeport.

First, the EKG.

The patient was an elderly lady, brought in from an nursing home, with a low blood pressure, but not looking "shocky," or at least not yet. Although there was no chest pain or other obvious cardiac complaints, and no arrhythmias, the medic nonetheless (wisely) obtained a 12-lead.

Of course, shooting an EKG, like any other  data point you obtain in the field, has been compared to picking your nose in public - namely, what do you do with the results?

So what would you do with this booger? Extra points if you find the occult STEMI.

The medic, correctly, did not call for cath lab activation.

Now the picture!

Same medic, bringing in a 80-ish year-old women who, because of dementia and multiple strokes, has had her diet restricted to pureed & thickened foods. Unfortunately, her husband, while preparing dinner, turned his back for just a moment while preparing himself a meal. When he turned back she wasn't breathing so well, and was starting to look a little blue-ish.

Not quite this bad.

By the time the patient showed up at the ED, however, she had a mild dry cough, but had her reassuringly pink skin color back!

The paramedic, not sure if we fully appreciated what had happened, held aloft with his MacGill forceps the spoils of the hunt:

Gross.

Nonetheless, a nice save! I have no idea how this lady managed to stuff a piece of meat that size into her mouth, let alone get it down into her epiglottal zone. Definitely a case that required on-scene, definitive, airway management.

Okay, that's it - no deep topics today.

But the next post will be more "meaty," I promise.

Did the machine miss something big?

I'm going out on a limb here, since I don't have the cath report yet. But I'm getting it soon, so we will have some closure on this!

The case:
A 68 year old male called 911 for "10/10" chest pain, and took aspirin before EMS arrival. Nitroglycerin was given by the medic, but it dropped the BP. Some normal saline took care of that, and transport was expedited.

The first ECG:

Computer interpretation: "Widespread ST-T abnormality suggests myocardial injury/ischemia"

Literally seconds later, the monitor showed a burst of activity:

A repeat ECG then showed:

No further events enlivened transport to the tertiary-level, primary-PCI facility.

So what does the first ECG show?
This ECG suggests a proximal LAD occlusion in two different ways, and justifies cath-lab activation, in my view.

The first pattern is likely familiar to astute 12-lead ECG readers. There is widespread depression throughout the ECG (II, III, aVF, and V3-V6), and ST elevation in aVR. Such a pattern indicates either severe 3-vessel disease or severe occlusion of the left main artery.

The second indication of LAD occlusion is not as well-known. Note the upsloping pattern of ST depression in the precordial leads.  This is distinct from the horizontal or downsloping pattern that you often find with a posterior AMI.

For example, this posterior MI demonstrates horizontal ST depression:

Source

Another example of a posterior MI shows a downsloping pattern of the ST segment:

Source

By contrast, in our ECG we have a sharply upsloping ST segment. Furthermore, it terminates in a tall, fairly sharp, T-wave.

DeWinter "waves"
Back in 2008, de Winter and a few other authors described a ECG pattern that they had seen in 2% of anterior AMIs. Interesting, all of the patients with this pattern had occlusions of the LAD in the proximal region - a very serious blockage that could infarct a good chunk of myocardium.

[T]he ST segment showed a 1- to 3-mm upsloping ST-segment depression at the J point in leads V₁ to V₆ that continued into tall, positive symmetrical T waves. The QRS complexes were usually not widened or were only slightly widened, and in some there was a loss of precordial R-wave progression. In most patients there was a 1- to 2-mm ST-elevation in lead aVR

They offered 8 examples of the precordial ST-T pattern:

Interesting looking ST segments and T-waves! Comparing these examples to our patient, looking at a blow-up of the precordial leads:

Upsloping ST-segment depression? Check.
Tall, positive, symmetrical T waves? Check.
Loss of R-wave progression? Check.
Normal-width T-wave? Check.
ST-elevation in aVR? Check.

So even without the 20/20 hindsight that blogging affords me, I'm anticipating a proximal LAD occlusion.

The final ECG
It appears the ST segments have normalized - both the ST elevation in aVR, and the ST depressions in multiple leads have returned to baseline. Even though this spontaneous reperfusion is an encouraging development, the patient still requires emergent angiography in my opinion, given the high likelihood of a dangerous, unstable lesion.

The Bottom Line
There - you know what I know now. Do you see anything that points to an alternative diagnosis, another concomitant problem, or different management?

I'll dig up the final results, and and them in the comments in a few days.

Why do paramedics not want to treat pain in kids?

Forgive me for my provocative title.

Of course, most paramedics do want to treat pain in kids. It's been shown, however, that EMS (like many areas of medicine) doesn't do a great job treating it. Why is that?

Quantitative versus qualitative research

Studying many questions in EMS is relatively straightforward, as you can always look at the numbers.

Does prehospital CPAP prevent intubations? Just count how many people get tubed in the ED! Does use of a CPR-machine save lives? Well, count up how many patients get ROSC!

These sorts of studies, where we look at numerical comparisons, rates, and statistical differences are all quantitative - these rely on obtaining and comparing numbers. To answer this question (about what keeps medics from providing analgesia to pediatric patients), however, EMS researchers in Rochester NY used a qualitative method. 

So this study didn't involve measuring or testing, and collecting a bunch of numbers. Instead, the authors went out and, essentially, listened to what paramedics had to say on this topic!

PubMed link

How they did they do the study?
Getting a paramedic to open up and share their experiences is not exactly the hardest thing in the world...

Pictured: A whole book about medics talking.

 Far from just writing down a bunch of "war stories," however, the authors followed a few steps to ensure they obtained useful and credible information. 

They recruited medics from a variety of agencies in western NY state, with differing levels of experience, and varying levels of comfort dealing with kids. They also brought in a paramedic to actually conduct the interviews, figuring that this would be less intimidating than a physician or PhD. They also tried to figure out a useful way to guide the interviews, designing a set of provocative questions, but also planned to let the medics talk freely and widely on the topic.

So what did the medics say?

Some surprising things!

Now, this sort of research isn't designed to produce statistics or predictions, but I want to highlight some of the results that were felt by the authors to be new and significant, as well as direct quotations from the interviews.

The authors found that "the majority [of medics] viewed relieving pain as unimportant and not part of their job."

They also saw that the medics, in general, "were also concerned that the patients might have an unknown allergy to morphine ... [and had] a similar concern for causing respiratory depression"

Lastly, they found that paramedics "reported receiving generally no response or a negative response from hospital pediatric ED staff."

There are a number of other results and quotations in the article, but I think that these 3 selections convey the general point. Analgesia for pediatric patients is seen as fraught with risks, and is not emphasized as a priority.

As the medics see it, there are few ways to win, and many ways to lose!

Given the inconsistent support from supervisors and ED staff, there is every incentive to shove the issue off, and let the ED handle analgesia.

So, what can be done?

Paramedics are known for their aggressive attitudes in the field, and they don't shy away from challenges. Drilling needles into bone, cardioverting VT with a pulse, or even giving tPA in the ambulance - medics get into the field so that they can tackle the tough problems, not avoid them!

So it's not too hard to figure out where the medics acquired these perceptions about pediatric analgesia. They got these ideas from their supervisors, from their EMS educators, from their rotations in the ED, and in discussions with ED nurses and medical control doctors every day. I agree wholeheartedly with the authors when they conclude that

... the onus of responsibility to change the belief structure regarding pediatric pain management lies not with the paramedic, but with physicians, hospital staff, and paramedic supervisors.

The Bottom Line...

Medics, like all of us, like to engage in a modest amount of medically-appropriate bragging.

"Modest bragging" source

Whether it's sinking a tight ET tube, reversing a bad CHF with aggressive CPAP and nitro, or cardioverting VT in a patient's living room - it's all good material for illustrating your medical prowess. So why not with analgesia?

Perhaps in the future, we'll have quotations from medics that read a little different from those in this study. So, if medical control physicians all do our job right, we'll hear medics bragging about how many mg/kg of morphine they gave, or how quickly they medicated the kid with a femur fracture!

With that in mind, I made my own EMS meme. If we do our jobs right, maybe this will be less of a joke, and more of a reality in the future.

I can getz artsy on Cheezburger!

Should we increase the duration of CPR before "calling it?"

If you have worked in EMS for longer than one shift, you know how most codes will end up.

True story: During my tech/medic days, I got to tie a few toe tags myself.

This is old news - if EMS doesn't get a pulse back by the time the patient is moved onto the longboard, the prognosis is grim.

That's why the authors of the ACLS guidelines support appropriate field termination-of-resuscitation, writing in the 2010 Ethics portion of the ACLS guidelines:

Field termination reduces unnecessary transport to the hospital ... , reducing associated road hazards that put the provider, patient, and public at risk. In addition field termination reduces inadvertent paramedic exposure to potential biohazards and the higher cost of ED pronouncement. More importantly the quality of CPR is compromised during transport, and survival is linked to optimizing scene care rather than rushing to hospital.

They provide a suggested algorithim for field termination by paramedics, based on the most recent evidence:

The protocols for the Sponsor Hospital Council of Greater Bridgeport reflect this evidence. 

The relevant section, 3.16,  provides criteria for termination, which are, in part:

Most EMS systems around the country have similar protocols, and comfort with "calling it" onscene has been increasing in the EMS community.

And then this happens...

You can always trust what you read on Twitter!

Oh boy - are we going to go back to transporting them all to the ED?

So what's this new study?

Link

This study used data from a retrospective registry, collecting data from 435 hospitals over a 9-year period (2000-2008). They ended up with about 65,000 patients who had had a cardiac arrest while in the hospital.

First, they looked at how long patients received resuscitative efforts, and calculated the average duration of CPR at each hospital for patients who did not have ROSC. 

That last part is key - when the news reports talk about "how long patients got CPR," what they really mean is "the average duration of CPR at each hospital for nonsurvivors." Subtle, but important difference.

Next, they figured out a way (regression analysis) to make all the patients and hospitals "equal." For example, patients who came in to the hospital with CHF were clearly at higher risk of cardiac arrest than those who had cellulitis, so they figured out the difference, and calculated it in mix.

Last step - they looked at the "average" cardiac arrest patient at the hospitals with the longest average duration of resuscitation, and compared the survival rate with patients at the hospitals with the shortest average durations.

What did they find?

First, they found a some variation in how long hospitals would attempt to resuscitate patients. The hospitals that "coded" non-survivors for the shortest time did so for about 16 minutes, while those hospitals in the more persistent group ran resuscitations for an average of 25 minutes. These averages hide, of course, a lot of individual variation.

So how did the patients at the 16-minute hospitals (quartile 1 in the figure below) fare compared to those at the 25-minute (quartile 4) hospitals?

There was a 12% difference. 

Put another way, for every 100 patients that survived a code at the 16-minute hospital, the 25-minute hospitals (on average) would have 112 survivors.

So, does this apply to my patients in the field?

First, keep in mind that this study only looked at in-hospital cardiac arrest. Importantly, they excluded arrests that occurred in the ED, and EMS codes were not included either. We already know that in-hospital cardiac arrest patients are different from those in in the pre-hospital realm, so the results are not immediately applicable.

Second, the results are modest, and may be as small as only a 2% survival advantage if you look at the confidence intervals (95% CI) in the figure.

But probably the biggest reason to not let this study change your practice is that it wasn't comparing patients - it was comparing hospitals. And those hospitals were likely doing more than just doing CPR for longer periods of time. They may have been employing better CPR, getting people and resources to the patient faster, or using better post-resuscitation care. We don't know anything else about the hospitals except that they tended to do CPR for longer on the non-survivors!

The Bottom Line
Data from retrospective, registry trials like this is provocative, not least because it can generate statistical results from the large numbers of patients included. It's impossible, however, to explain those results, or show cause and effect. For that we need prospective trials. 

I don't see anything in the current study that could justify changing our current approach, so keep following the current protocols for termination, provide quality CPR, and if you do have a reason to transport while continuing resuscitative efforts, do so safely!