It's no secret that I am a diehard advocate of progressive prehospital medicine. I am also a proponent of evidence-based medicine. Sometimes these two views can be conflicting because of the lack of evidence to back new medicine. I have often changed my views on certain treatments in light of new research. The outstanding presence of bias and valid arguments associated with medicine drives me to keep reading on, even after discovering what may seem like a correct answer. Looking in one place will never be an adequate solution to a complicated topic, at least this is true when it comes to medicine.

Here in my EMS system we practice evidence-based medicine. We also like to consider ourselves a pretty progressive organization. Our medical director gives us a lot of leeway, and holds us to a pretty high standard. You could see five different medics treat the same patient five different ways here in our system, and they will all have valid arguments for each treatment.

When it comes to a traumatic injury, backboards and neck collars are used at the discretion of the lead paramedic. I have seen paramedics that immobilize every patient they encounter that was involved in a car accident or any other blunt force traumatic event. I think this might be what we call CYA (cover your ass) procedures. These medics might have seen a missed spinal injury be improperly treated in their career, and an unfortunate victim of that care acquire a lifelong need for a wheelchair.

I have developed my own systematic approach to these trauma patients. Of coarse manual cervical spine immobilization is applied upon initial contact. If the patient is under the influence of alcohol, he/she gets the full package, board and collar. I have just had too many drunks that haven't felt a stab wound or broken arm, let-alone a possible spine injury. This is also a strong consideration with anyone who has recently taken analgesics or elicit drugs. If they aren't under the influence of drugs or alcohol I give an appropriate physical exam. I consider the mechanism of injury and touch the patient to assess for tenderness. If the patient is pain free, able to move all extremities, and rotate their head without pain or involuntary movement, they get to stay off the board. This isn't evidence-based and I have begun to question my own rational.

Luckily, I haven't had this go wrong. I pride myself in my assessment skills and appreciate the patient's comfort level. A backboard is a very uncomfortable bed cushion for someone who doesn't need it. Quite often, if they didn't have pain to begin with, they will after being on a backboard for only a few minutes. Of coarse, muscle pains from being on a hard board is nothing in comparison to chronic paralysis from being mishandled; I can also appreciate this fact.

Recently I read a statement on Trauma.org that has sparked yet another need for further information gathering[1]:

This is a pretty blunt statement; no conclusive evidence, not any? What is Trauma.org's definition of conclusive, I wonder. I know there must be something out there that supports the paramedic's ability to adequately assess their patient and make a decision like this. I also wonder if the statement is made only in regards to removal of previously applied spinal immobilization. What kind then, manual immobilization or the whole package? Or is this statement in regards to all blunt trauma patients; should we immobilize them all? Maybe they are referring to only neck and/or back pain patients. The list of questions has quickly become a long one, luckily the authors listed their sources.

The first source listed is from a journal that I personally subscribe to, Prehospital Emergency Care. Unfortunately, this is from 1999 and I don't have the issue. I used Medline to find the article but was only able to come up with the abstract. Here is the abstract from the cited study[2]:

INTRODUCTION: Traditional EMS teaching identifies mechanism of injury as an important predictor of spinal injury. Clinical criteria to select patients for immobilization are being studied in Michigan and have been implemented in Maine. Maine requires automatic immobilization of patients with "a positive mechanism" clearly capable of producing spinal injury. OBJECTIVE: To determine whether mechanism of injury affects the ability of clinical criteria to identify patients with spinal injury. METHODS: In this multicenter prospective cohort study, EMS personnel completed a check-off data sheet for prehospital spine-immobilized patients. Data included mechanism of injury and yes/no determinations of the clinical criteria: altered mental status, neurologic deficit, evidence of intoxication, spinal pain or tenderness, and suspected extremity fracture. Hospital outcome data included confirmation of spinal injury and treatment required. Mechanisms of injury were tabulated and rates of spinal injury for each mechanism were calculated. The patients were divided into three different high-risk and low-risk groups. RESULTS: Data were collected for 6,500 patients. There were 209 (3.2%) patients with spinal injuries identified. There were 1,058 patients with 100 (9.4%) injuries in the first high-risk mechanism group, and 5,423 patients with 109 (2%) injuries in the first low-risk group. Criteria identified 97 of 100 (97%) injuries in the high-risk group and 102 of 109 (94%) in the low-risk group. Two additional data divisions yielded identical results. CONCLUSION: Mechanism of injury does not affect the ability of clinical criteria to predict spinal injury in this population.

So the first thing that stands out to me is the year the study was done. 1999 was 10 years ago. Sure, it isn't that long ago, but think of how much things change in the medical field in a matter of a few years. That doesn't mean that the data isn't valid though. The next thing that stands out is the study itself. It is questioning the relevance of mechanism of injury(MOI)in determining a cervical spine injury, not the ability of a paramedic to adequately clear a cervical spine.

This study gave the paramedics a set list of criteria, it didn't expand off of the paramedic's assessment skill. The study used paramedics in their research, but they were not testing the medics, just the method. So if the criteria were invalid, how does this reflect on the assessment skill of a paramedic?

Unfortunately this abstract leads a lot to the imagination. I'm not sure if the low risk group was intended to be injury free and ended up with 94% of them having injuries (highly unlikely). It seems to me like their low risk criteria appropriately identified 94% of the injuries and the high risk criteria caught 97% of the injuries. That seems to have pretty good specificity to me. I am still looking for the full text for this study (hint hint Rogue Medic).

The conclusion pretty much states that MOI does not effect clinical criteria when predicting spinal cord injury. Does this mean that a possible spinal cord injury is not at all predictable by the MOI. I didn't find conclusive evidence (be it just an abstract) that states paramedics should not be clinically clearing the cervical spine in the field.

That isn't exactly what I am looking for though. Without evidence of benifit, we wouldn't be practicing evidence-based medicine. The next refference that Trauma.org cited was a study from The Journal of Trauma. Once again, all I could find (even in my college's extensive database) was the abstract[3]:

OBJECTIVE: Determine the level of agreement between emergency medical technicians (EMTs) and emergency physicians (EPs) when applying an existing emergency medical services/fire department protocol for out-of-hospital clinical cervical spine injury (CSI) clearance in blunt trauma patients. METHODS: Prospective observational study of consecutive blunt trauma patients transported by emergency medical services/fire department during a 3-month study period. The setting was an urban Level I trauma center. Measurement of interrater agreement (kappa) was determined. RESULTS: Mean age of the 190 patients was 34+/-19 years (range, 6 -98 years). Fifty-nine percent of the patients were male. One hundred forty-six patients (77%) were immobilized by EMTs; 17 of these patients were clinically cleared by EPs. Forty-four patients (23%) were clinically cleared by EMTs and presented without CSI precautions; of these, 61% (27 of 44) were immobilized by EPs and 57% (25 of 44) had cervical spine radiographs obtained. Overall, 141 patients (74%) required radiographic clearance. CSI were detected in five patients (2.6%); all five were immobilized in the out-of-hospital setting. Overall disagreement between EMTs and EPs regarding out-of-hospital CSI clearance occurred in 44 patients (23%) (kappa=0.29; 95% confidence interval, 0.15-0.43; p less than 0.01). CONCLUSION: Significant disagreement in clinical CSI clearance exists between EMTs and EPs. Further research and education is recommended before widespread implementation of this practice.

Wandering a bit from the recent All Cardiac - All of the Time drift of Paramedicine 101, but not entirely, I must point out an excellent post on Heroin Overdoses by a blogger, who really is much more imaginative than that post title suggests - Too Old To Work, Too Young to Retire. He is just as direct as the title suggests.

Here is an example of education on junkie slang. It is both translated to everyday English and comes with an explanation of the most effective and most appropriate treatment.

commonly known as "nodding off" or being "on the nod". The person is usually easily woken up by either a shake on their shoulder or speaking to them loudly. Despite what some in EMS think, this is NOT an overdose. Because it is the desired effect, I refer to this as "a dose".

He describes the protocol that is in place where he works. His protocol uses respiratory depression as the criterion for treatment with naloxone (Narcan). Some of us have protocols that require treatment with naloxone for Altered Mental Status. I am not in favor of treating opioid overdoses under Altered Mental Status protocols, because this discourages the medic from delivering appropriate care. In stead, the medic ends up delivering vending machine care.

Enter minimal diagnostic criteria _____, remember to use only approved EMS terminology (the protocol vending machine does not recognize unapproved terminology), press Enter, and out pops a treatment. Eureka! No Fuss, No Muss, No Thought, No Possibility For Error. At least, this is the way that many seem to design protocols. Of course, the word diagnostic would not be in the list of approved terminology.

If we are designing a protocol with Foolproof in mind, aren't we designing protocols to encourage the hiring of fools? How can we deny that we expect fools to use the protocols, if we are designing the protocols with fools in mind? We are designing protocols to prevent fools from doing too much damage, while using those protocols. Wouldn't it be better to just keep the fools from being authorized to poison patients?

There is a great article by Dr. Bledsoe on the error of using a set treatment for every unconscious patient.^[1]

TOTWTYTR points out the use of other diagnostic information in coming to the conclusion of heroin overdose. In addition to the respiratory depression, needle marks, pinpoint pupils, being in a shooting gallery, the presence of injection supplies, . . . are just some of the information that would lead a competent medic to use naloxone in treating this patient. Pennsylvania has a pretty good example of this in their protocols.^[2]

With such a patient, my goal is not awake and alert, but breathing adequately. True, they will not have a GCS^[3] of 15, but that is where the word competent becomes important. Were we called to the scene because a heroin user was sleeping (not awake), or because a heroin user could not go out and steal something to pay for more drugs (not alert enough to act as a lookout), or because a heroin user was not breathing adequately?

How awake do we want the patient to be?

How alert do we want the patient to be?

How much do we want to endanger EMS crews, just to have the vital signs part of the paperwork look pretty?

Is it possible that an HOD (Heroin OverDose) has a stroke at the same time? Gosh, injecting various impure and not exactly FDA approved solutions into the veins could result in something that should not be in the brain, ending up in the brain. And I am not referring to the heroin, but particles that do not become fully dissolved in the solution that is injected, or particles that precipitate out of solution at some point. These would not be described as good in the brain. What is baseline function of the addicted brain? Is it always GCS = 15? Can we identify signs of a stroke, even if the patient's GCS ≠ 15? Yes. Why do we think we could not?

Reading TOTWTYTR's blog is a good way to avoid the dumbing down of EMS. He does not only mention the shortcomings of EMS in this post, but points out the abuse of pulse oximetry in the hands of a nurse. Is he just looking for an opportunity to criticize nurses? No. He is pointing out that this is somebody who should not be a nurse - perhaps a Faux Nurse. No more representative of competent nurses than a Faux Paramedic (Medic X) would be representative of competent medics.

Anyway. Go read the whole thing. It is longer than his usual post (bad kettle), but it is very informative and entertaining.


Footnotes:

^ ¹ No more coma cocktails. Using science to dispel myths & improve patient care.
Bledsoe BE.
JEMS. 2002 Nov;27(11):54-60.
PMID: 12483195 [PubMed - indexed for MEDLINE]
The Pubmed link is to the abstract. For the full article as a pdf, click below.
Free PDF


^ ² Altered Level of Consciousness
Pennsylvania Adult Statewide ALS Protocol
Note # 6
Pages 78/121 and 79/121 enter 78 in the page count window.
Nov. 2008 posting of PA ALS Protocols in PDF



^ ³ Glasgow Coma Scale/Score
Wikipedia
Article


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I am now going to post these strip teases simultaneously on here and on emtcity.

You are free to provide your interpretations within the comments of each strip tease.

This means be aware, if you don't want any hints, don't look at the comments until you have your guess.

The answers will be posted shortly after, but post dated so they don't pop up right on top of the strip tease.

There will be a link to the answer placed on the bottom of the strip tease post.

I will start with Strip Tease 10, and get the old ones posted on here soon.

81 year/old female with altered mental status.

Here is part of the problem I see with getting people to understand heart blocks. The first thing that is noticed is sometimes what looks normal and comforting. We do not go looking for problems, even though in EMS, we are not supposed to be called for things that are not problems. We are setting ourselves up for making the problem worse. Here is the unmarked copy of Adam's Complete Heart Block ECG.





When I would show strips like this to people in ACLS (mostly nurses, some doctors, some respiratory, occasionally a paramedic), the first thing someone would comment on is the least important, most misleading part of the strip. The single instance of the normal looking PR interval. Some people see the normal PR interval and assume that all of the PR intervals are normal, just difficult to identify. This is the wrong approach.

This is one of the reasons I keep highlighting the importance of science in EMS.

What does science have to do with this?

The approach of science is to examine research with the attitude of trying to find where there are problems. Falsifiability. Science is about performing research, then publishing it with the expectation that others will look for the problems with the study. And not being mad at those who find flaws in the research. The critic is not the one who made a mistake. That does not mean that the critic would be able to do research as well as the researcher being criticized, but that has nothing to do with science.

Research is validated only when no significant problems can be found with the research.

So what does this have to do with EMS and ECG reading?

We too easily dismiss a patient's complaint as bogus, when we have not assessed the patient thoroughly enough. If you see the normal PR interval, have you identified this as a healthy rhythm?

Certainly not. We need to keep looking for problems until we have ruled out the potential problems. Many times that is impossible in EMS, but it does not stop some medics from dismissing a patient's complaint as bogus. This is not good medicine.

Here is the same ECG, but I have marked the normal PR interval on this blatant heart block with a circle. The three beats on top of each other are the same beat, just presented in different leads, so this is three instances of just one normal PR interval. I have also drawn a line over the changing PR intervals. Looks like a pattern.





The PR intervals over the ECG do seem to form a pattern. Longer, longer, longer, repeat. Has Adam missed, right after posting a music video on the topic, a Wenkebach block - a 2^nd degree type 1 heart block?

There does seem to be the progressive lengthening of the PR interval. What about the dropped beats? In order to compare the R to R interval in a way that makes this a bit clearer, I copied each pair of beats, after the first pair, and placed the copies under the first pair of beats. I drew a line down the middle of each of the first 2 beats and tried to line up all of the others with those lines. Is there any lengthening of the R to R interval that would indicate a dropped beat?




Click on the image to make it bigger.

I don't see any significant difference. Without any dropped beats, this cannot be Wenkebach. Longer, longer, longer, repeat. Wenkebach is longer, longer, longer, dropped. The number of longers is not always three. It could be two, or four.

There is a slight variation in the R to R interval. A variation that is more than just my lack of cut and paste skill. Does this variation mean that these beats are not controlled by the ventricles? No.

The vagus nerve is often the culprit in heart rate variability. The vagus nerve is not supposed to connect to the ventricles. However vagal innervation is not the only reason for heart rate variability. Some patients also will have the vagus nerve attached to their ventricles.

This is a nice example of a Complete Heart Block. The terminology is something that cardiologists may not approve of, but I think this is adequate for EMS use. The understanding of the concept is much more important than the terminology.

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This sparked some great discussion within the comments section. I had always been taught to stay away from Adenosine or Calcium Channel Blockers for these patients but only recently learned that Amiodarone isn't the best treatment either. I thought maybe it would be a good idea to further elaborate on WPW right here for those who may not know this stuff yet. Its also a good chance for me to learn something new.

WPW or Wolff-Parkinson-White syndrome is a condition where an accessory pathway exists between the atrium and ventricle. This means that there is an extra path of conduction, and its a faster one. You know how the AV node pauses the impulse from the SA node to allow for ventricular filling? Well the extra pathway, also known as bundle of kent, has no pause, no yield sign so-to-speak. So when the patient with WPW has an impulse that starts at the SA node like a healthy heart, but travels quickly through the bundle of kent this causes an early depolarization of the ventricles. Pre-mature ventraculation ventricular depolarization, most commonly called pre-excitation. Check out the image below.

This is an image showing a possible location of the accessory pathway. Check out the next image to see how this can lead to conduction abnormalities.

With WPW, the conduction bypasses the AV node. Since the PR-interval is a representation of the pause at the atrioventricular junction, without the pause you get no PR-interval. One of the classic findings of WPW on an ECG is a shortened PR interval followed by a delta wave. A delta wave is a slurring upslope of the QRS, this causes the complex to be wider than normal. The next image shows the use of the bundle of kent for antidromic conduction.

Antidromic atrioventricular reciprocating tachycardia(AVRT). Commonly mistaken for ventricular tachycardia because of its morphology, antidromic conduction is still created in the atrium. In antidromic conduction the impulse travels down the bundle of kent and pre-excites the ventricles retrogradely. Since the AV node is bypassed atrial rhythms may be much faster than normal. Your 3:1 atrial flutters can now be 1:1! So if you have an abnormal pacemaker, or an atrium that wants to beat faster than normal, it can. This is pretty dangerous and may in fact lead to ventricular tachycardia or ventricular fibrillation. The images below show orthodromic conduction.

Orthodromic AVRT. This is a little bit more difficult to diagnose. Since the conduction works an an antegrade direction, just like normal conduction, it remains narrow. The rate is accelerated because of the bundle of kent being used as a reentry circuit. The electrical impulse can quickly re-enter the atrium via the extra pathway. This isn't good. Take a gander at the next image.

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