I Hate Adenosine

You arrive to a scene to find an otherwise healthy 28-year old male complaining of palpitations with slight dizziness on exertion for approximately 30 minutes.  This event started at rest (watching TV).  His blood pressure is 110/70, heart rate as you see it, and a respiratory rate of 20.  He denies taking medications and being allergic to anything.  You put him on the monitor and the initial view shows you:

Source: EKG World Encyclopedia http://cme.med.mcgill.ca/php/index.php ,
courtesy of Michael Rosengarten BEng, MD.McGill

This shows a regular, narrow complex tachycardia at a rate of about 190 (I plan on discussing types of SVT in a later post, so we can just go with SVT for now).  What would you do for this patient?  The normal prehospital algorhythm calls for IV access, a 12-lead ECG, vagal maneuvers, and adenosine.  ACLS calls for 6mg followed by a second dose of 12mg if the first doesn’t work (my agency’s protocols call for 12mg, with base contact for a second 12mg dose).  Some agencies have the option of beta blockers or calcium channel blockers, but that is pretty rare in normal paramedic protocols. According to ACLS, if the patient had altered mental status, was hypotensive, was shocky (whatever that means), or was presenting with ischemic chest pain then we should cardiovert him at 100 joules.*

Let me take a minute here and remind you that I have nothing to do with your protocols, policies, QA reviews, or your ability to continue to receive a regular paycheck.  But I want to share my thoughts on this subject. 

The reason for this post is that I hate adenosine. 

The majority of SVT patients that I have seen in my career generally present something like the above scenario.  So as most paramedics see it, the situation is presenting them with two choices: adenosine or ride the lightning (synchronized cardioversion).  In regards to cardioversion, my threshold is higher than the one listed in ACLS.  I hold off until there is an alteration in level of arousal, as compared to an alteration in mentation.  I need a patient to be difficult to arouse, at a minimum, before I am willing to blast them.  I’m not talking about a change in mentation – not confused, confused, disoriented, something like that.  The patient needs to be sick enough (with hypotension and the arrhythmia) to alter their AVPU level.  I don’t need to weld confused people…

So adenosine is the choice, right?  Electricity is for really sick patients and adenosine is for people who aren’t that sick.  That’s comforting – a nice, easy binary decision that even an average medic can make when confronted with a narrow complex tachycardia.  The problem that I have is that adenosine is not harmless.  It stops the patient’s friggin heart!  And it hurts!  And it can make them worse.

I can hear voices in my head: “But it has such a short half-life, the period of asystole and pain is pretty short.  I’ve never had a problem with it.  It is safe and solves the patient’s problem.”  To those voices, I point out that if adenosine was not a big deal, then give it to yourself.  There are medications most paramedics have given themselves – D50 into 1000mL of saline when you’re feeling sick, or a neb when you’ve got some lung filth that isn’t clearing up.  I drank bicarb once for blisteringly painful heartburn (tastes pretty nasty).  But adenosine would not be on the list of those meds, even for the most maniacal medics.  Why?  Because the short half-life argument isn’t a good one.

Before getting into the dangers of adenosine, let’s think on the logic of giving the example patient above a dose.  He isn’t sick, else we’d be shocking him.  We are talking about stopping his heart for a fluttery feeling in his neck.  Think about that – stop a heart, however transiently, to fix the fluttery feeling.  To me, this seems like killing a fly with a sledgehammer.  All this depends on your transport time and the other specifics of a real life call, of course, but are you really comfortable about painfully stopping a person’s heart for a fluttery feeling?  Have you watched a patient get adenosine?  It is not pleasant for them.

Every medication administration is an exercise in your ability to weigh risks and benefits.  In the case of SVT, I am not always convinced we do a good job of understanding the risks of adenosine and weighing the benefits we expect to gain.  Adenosine can actually be pretty dangerous in some settings.  It can cause bronchospasm to the point of causing fairly severe problems (1), but the biggest problem comes when it is given to atrial fibrillation and atrial flutter.  Atrial flutter with 2:1 conduction can often mask the pathognomonic sawtooth pattern and be mistaken for SVT.  Administration of adenosine can cause the 2:1 flutter to accelerate to 1:1 flutter (2).  So I avoid grabbing the adenosine until I see heart rates that are unlikely to be 2:1 atrial flutter – heart rates faster than 170 at least, but I feel even more comfortable at rates faster than 180.

Atrial fibrillation is something to be avoided, as well.  First, adenosine plum doesn’t work to convert AFib.  It works by slowing or blocking conduction through the AV node, but doesn’t work on bypass tracts like a Bundle of Kent.  So adenosine can be especially dangerous if they have a bypass tract (which can be concealed).  You may not see the nice textbook-style delta wave on a 12-lead.  Adenosine can accelerate the rate to greater than 250 beats per minute, with subsequent hemodynamic instability (2-5).  Ventricular fibrillation can even occur (6,7).  So for me, any irregularity rules out adenosine.  Be careful – the difference between 188 and 214 beats per minute is the difference between 7 and 8 millimeters on the paper.  Irregularity can be subtle at faster heart rates!

I understand that the risk of adverse events is rare after adenosine administration.  But it does exist.  Are you sure you want to take the one in a thousand roll of the dice for otherwise stable palpitations? 

I would like to preach the strengths of what other websites have called benign neglect.  Watching and monitoring a patient is often the right answer.  Not every problem needs to be solved in the 15 minutes that I am with a patient.  So, to me, adenosine is useful in a narrow subset of patients who don’t yet have an altered level of arousal, but who need to have the SVT terminated – hypotensive, ischemic chest pain, that kind of thing.  All the other SVT patients with the fluttery feeling get watched (in my system with short transport times). And I avoid adenosine if there is any irregularity to the rhythm. 

As with all medications, the risk needs to be outweighed by the benefits.  If the only expected benefit is to get rid of palpitations, then there needs to be essentially no associated risk.  With adenosine, there is some risk.

Consider practicing better vagal maneuver skills.  I have seen paramedics go through the motions to cross vagal off their list before moving on to adenosine.  Instead, actually work with patients to get a vagal maneuver that works.  Also consider a fluid challenge.  200 or 300 milliliters of saline often terminates SVTs.  I think you may be surprised at what skilled vagal instructions, fluids, and patience converts.

By the way, the ECG above is an example of AVNRT that received adenosine with successful conversion.  The whole 12-lead shows adenosine hitting the heart in V4-V6:
 

If you’re interested in a detailed description of how adenosine works, check here, here, and here.  Have a good one, and stay safe. 


 *As an aside, does anyone else find it weird that ACLS doesn’t call for pre-shock sedation or analgesia?


1. Burkhart KK. Respiratory failure following adenosine administration. Am J Emerg Med. 1993;11(3):249–250.
2. Mallet ML. Proarrhythmic effects of adenosine: A review of the literature. Emerg Med J. 2004;21(4): 408–410.
3. Exner DV, Muzyka T, & Gillis AM. Proarrhythmia in patients with the Wolff-Parkinson-White syndrome after standard doses of intravenous adenosine. Ann Int Med. 1995;122(5):351–352.

4. Haynes BE. Two deaths after prehospital use of adenosine. J Emerg Med. 2001;21(2):151–154.

5. Nagappan R, Arora S, Winter C. Potential dangers of the Valsalva maneuver and adenosine in paroxysmal supraventricular tachycardia--beware preexcitation. Crit Care Resusc, 2002 Jun;4(2):107-11.
6. Shah CP, Gupta AK, Thakur RK, et al. Adenosine-induced ventricular fibrillation. Indian Heart Journal, 2001;53(2):208–210.
7. Adenosine pkg insert.

Third Rider Introductions

My first third-ride, as a part of my initial EMT class in 1994, was with a private ambulance in the suburbs.  There are four things that I specifically remember about that shift.  First, 21-year old me had a really hard time coming up with blue pants and a plain white shirt.  I mean, who owns clothes like that?  The only white shirt I had was a concert tee that said Ozzy on it.  I had to go buy a white polo and blue pants.  Second, I realized that this ambulance crew went to a lot of nursing homes.  I didn’t realize there were that many nursing homes in the state, let alone in one town.  Third, I remember a head-on crash at highway speeds.  There must have been close to 100 mph combined impact.  What I remember most was that the surviving driver’s lower leg wrapped around the brake pedal so that he was looking at the sole of his foot.  Nasty and cool all at the same time to 21-year old me.  And finally, I remember what the paramedic told me when I started the ride: “Sit on your hands.  If I don’t see your hands all shift, you will pass.  If I see your hands, I will take you back to your car and end your shift.”  I didn’t want to tell him that he had nothing to do with some imaginary pass-fail ride grade.  Ass.

My current introduction to third riders is a little different from that one.  I also include the fact that I shouldn’t ever hear a rider.  Just kidding.

At my agency, we have riders along for shifts for a lot of reasons: EMT students, paramedic students, new hire EMTs and paramedics, military trainees, resident physicians, medical students, and so on.  It is a rare shift that I don’t have a rider along during some parts of the year.  My introduction to riders is always about the same:

• Introductions

• Welcome

• Shift goals

• Safety

• Dispatch number

• Complaining

• Crew status

• What they’re bad/good at

I start with who my partner is and who I am.  I make sure that they get our names, and I also talk about what our respective positions in the agency are.  Who’s a medic, who’s an EMT, how long we have been there, that kind of thing.  The name thing is more important than most people realize – a new rider’s head is spinning with excitement and new facts aren’t necessarily being laid down into their memory banks.  Make sure they get your name.

I ask them who they are, and make an actual effort to remember their name.  It is embarrassing to call out “Hey, uh, dude, need a bathroom or anything?” to the back of the ambulance all shift.  I’m also interested in finding out what experience they have in medicine and in the prehospital setting, whether and where they are currently working, and generally get them to tell me a little about themselves.

There is a scandalous rumor that my affect makes me seem as though I am not the most warm and welcoming person.  So I need to make a specific effort to make sure the rider knows that they are welcome.  I’m glad to have riders, I love to teach, and if they have any questions they should never be embarrassed to ask.  They are completely free to ask whatever they like, wonder about anything, and ask me to explain what I'm doing.  I probably had questions on that first third ride but was concentrating too hard on keeping my palms clamped to my butt cheeks to ask.

I ask riders why they are riding.  What do they need to get out of being with me on the shift and what are they hoping to get out of the ride?  There is a difference.  Most rides are just being on the ambulance for 10 hours, but riders have aspirations and hopes of what they will see and what they will be able to do.  I can do a better job teaching if I know that the rider is an EMT student versus a third year emergency medicine resident.  I have different things to show them and different expectations of them.  Some riders plan to work on an ambulance and some would like to work in an ED.  With residents, I need to make sure they are getting the non medical EMS operations picture – I don’t need to teach them how to read an ECG, but they do need to hear about our protocols, our pharmacopeia, plus any safety and system issues that come up.  I really want EMT students to perform a real exam on a live patient, I want paramedic students to start to use the knowledge that was just jammed into their heads, and I want residents to get an appreciation for the difficulty of information gathering without testing and imaging.  If you don’t know what they want to learn and at which level they should be expected to perform, then how can you successfully teach?

Next I move into the safety portion of the introduction.  There are just a couple of main points.  First, a rider should not get involved in anything in which they don’t understand completely.   Don’t lift a pram you don’t understand.  Don’t dive into a wrestling match if you don’t understand what you’re needed to do and where you should be positioned.  Don’t even spike a blood pump for me unless you are sure you know how.  This is safety for the rider, me, my partner, the patient, and everyone else on scene.  I need a rider lifting the business end of a pram for the first time with grandma on it like I need a hole in the head.  And I don’t know what kind of worker’s compensation an EMT student has, but blowing out their back lifting a big patient improperly is probably bad juju.  Riders need to be told that I don’t need their help.  My partner and I would handle the situation as a pair if the rider weren’t there, so the rider being there is superfluous.  Don't let a rider get involved if they don’t know what they are expected to be doing and are comfortable doing it.

Second in regards to safety is to stay with me: “Don't wander off with the shady stranger into the basement cause he ‘needs to show you something.’  Don’t let the police block you out of the scene thinking you are a nosy bystander.  You can’t really be too close to me, and if you are a little too close, I will tell you.”  I don't want to have to divide my attention between the patient and wondering where my rider wandered off to.

Finally, it is conceivable that a rider could get left somewhere between calls.  This has never happened to me in 15+ years, but if they are in the 7-Eleven bathroom when a cop is shot two blocks away we may need to leave without the rider.  It is also conceivable that I am not paying attention, don’t know that the rider is still inside dealing with last night’s Mexican dinner, and go on the next call.  They need to know that it is not the end of the world if it happens.  I will know where I left them and someone will soon be by to get them.  Just hang out and read magazines or something for a few minutes and I will buy a meal to make up for it (if it is my fault).  This is the point that I make sure they have dispatch’s nonemergency phone number in their cell phone.  They can call dispatch to make sure someone is coming for them if it makes them feel better.

I give them dispatch’s number for another reason, which I try to clearly explain to them.  If they want to complain about me, or let a supervisor know about something I did, they just need to call dispatch and ask for a field supervisor.  I tell them this flat out.  There could be situations that can be misinterpreted – searching a patient’s bag can look like stealing to the uninitiated.  Restraining a combative patient can look like battery if you don’t understand what’s going on.  I know that I am never doing anything wrong, so I don’t mind if they tell my supe what happened.  I would certainly prefer that the rider asks me about it so I can explain, but if they are not comfortable with that they have my express permission to call the supervisor directly.  To me, it is important that a rider has a mechanism to bring his/her concerns to my boss.  Not one rider has ever taken me up on it.

Two final points.  First, I make sure they understand they are like a full-fledged member of the crew when it comes to things like bathrooms, food, and climate controls.  If the rider is cold, they need to speak up.  If they need to pee, they should say something (or at least keep making a whimpering noise).  We’ll get it taken care of.  Importantly, if they have an important piece of information about the patient or the situation that I seem to have missed, they need to tell me – just like a full-on crew member.

Finally, I ask them what they are bad at and need to work on.  What have other preceptors said that they need to work on?  This way I can focus on those lessons.  If they have a hard time with hearing blood pressures, I can give them a lot of practice with blood pressures.  If they are an IV student, I don’t want to be snaking their IVs.  If they have never performed CPR, I will make sure to get them on a chest if the situation arises.  If this was covered during the shift goal section, I will occasionally skip it.  But I try to finish the introductions on a positive note by asking them what they are good at.  Everyone is good at something, and I want them to tell me what they are good at.  It starts the shift off well.

Then we go have a good, productive shift.I know this seems like a lot, but it takes less than 5 minutes to talk out.  I promise, it took you longer to read this than it would to speak it.  There is a lot of reasoning and explanation in this post so the actual talk is much faster.  The main points are introductions, welcome, shift goals, safety, dispatch number, complaining, full partner status, and what they’re bad/good at.  That’s all it takes to set someone at ease, gain information that will enhance their ride, keep everyone safer, start to know a person who may be interesting, and be a better teacher for the shift.

And you won’t have a rider 20 years from now telling stories on the Internet about what an asshole you were…

Is there anything important I left off?  Let us know in the post comments if you have a rider checklist that includes other points.

I'm Sad Today

I wasn’t planning on posting today, so this is kind of a snapshot that hasn’t been well-edited.

Sometimes the professionalism and maturity of EMS employees makes me sad.  That is to say, the absolute lack of professionalism and the shocking lack of maturity make me sad.  Yesterday, the NocturnalMedic Facebook page asked, “What is the silliest thing you’ve ever been written up for?”  The comments make me despair for ever seeing EMS as a profession.  Some commenter highlights:

• Vandalism of an ambulance with medical supplies, potentially causing a dangerous drive, is not a silly reason to be written up.
• Hazing a new employee by writing on them?  Again, not a silly reason to be written up.
• Farting into the ambulance PA system is not a silly reason to be written up.  What state allows 8-year olds to work on ambulances?
• There are a lot of people written up for absenteeism.  One protested that appendicitis is not a reason to be written up.  My guess, however, is that they were not written up for that one call out – they were written up for a pattern of excessive absenteeism that violated agency policy.
• Violating a uniform policy is not a silly reason to be written up – unless this was a secret policy that nobody ever showed you and was pulled out of the “Save these policies for people we don’t like” cabinet.  You knew the rules.
• Not cleaning an ambulance at shift end is not a silly reason to be written up.  An unsanitary workspace in the healthcare field is dangerous.  I may have to work in that filth after you, our patients have nasty diseases, and we care for immunocompromised patients.
• Defecating into a trashcan while transporting a patient?  Seriously?!?
• Gory Halloween decorations hanging out of an ambulance is not a silly reason to be written up.  What is the opposite of ironic? 
• One comment pointed out that he wasn’t allowed to use a 12-lead because the agency didn’t have people that understood it.  I hope they are an agency of all EMT-Basics.

This kind of behavior is something that happens, I understand that.  There are some old medics that may have some stories about me in my early 20s.  I was suspended a long time ago for being a dumbass.  But when I was busted, my write up was not silly.  It was deserved and earned, and I made sure to change my ways.  Offering these examples shows an inability to even understand right from wrong.

Other comments make me sad, as well, if I assume that the story is correct.  Getting to calls too quickly, using too many gloves, removing a blanket from a patient to perform an exam, that kind of thing.  My guess, though, is that these “reasons” are not the whole story.  Getting to calls too quickly is probably more related to unsafe vehicle operation.  Removing a blanket and performing an exam can be done in the wrong setting – in front of crowds for example, so maybe that’s what that comment was about.

One way or the other, I’m sad.  I’m sad for EMS leaders who don’t adequately explain their position so that the employees being disciplined can understand the behavior that they need to correct.  I’m sad for the lack of maturity.  I’m sad for the lack of professionalism.  I’m sad for the lack of self-awareness in regards to behavior.  I’m sad for the blame transference and lack of responsibility I saw here.   

Maybe all of the comments are untrue and just Internet trolling.  This is why I try to avoid comment sections.

Next time you hear an EMS employee complain that they are not treated like professional peers worthy of respect by nurses and doctors, think of this.  Next time someone complains that they are treated like cab drivers by patients, think of this.

We do it to ourselves.