POTD: Endurance Medicine

It’s that time of year…the flowers are in bloom, my favorite trees with the flowers right on the trunks and branches, birds are singing, Spring is springing and people are running ridiculous lengths all for a free banana (which is really like a $120 banana if you count the registration fee).


As it turns out, I am one of those ding dongs taking part in the madness this year for the first time. And as an underprepared, pregnant person who knew better than to run but did it anyway and may have a tinge of rhabdo, I think this POTD deserves some attention and brings up some of the big concerns with endurance running (or cycling, or any other long duration workout). 


For those working event medicine at these events coming up, please pay special attention! I saw far too many bodies on the side of the route this weekend - seemingly young and probably otherwise healthy. Thanks to Matt Friedman who suggested this and provided some good graphics which I’ll attach here.


Let’s go about this stepwise…


You are a fellow runner in the Brooklyn Half Marathon and you come upon a participant who is lying on their back in the grass just off to the side of the course without anyone around them. You approach and what do you do? You all are trained in BLS (and even ACLS!) so you know what to do - “Hey! Are you okay? Can you hear me?”


Are they responsive? If the answer is NO, you know what to do. Check for pulses and if not present, initiate ACLS. If the answer is YES, this is actually a bit more complicated, but let’s simplify it into 3 categories based on temperature (ideally rectal but use what is provided to you in the field): hypOthermia (unlikely this time of year), normothermia, and hypERthermia. 


Hypothermia seems unlikely in this scenario, and my colleagues have taught on this in prior months, so for the sake of keeping it topical to this endurance running season, we will keep it to the latter two categories and their associated algorithms. 


Normothermia

Defined (by this resource) as a core temperature of 95-104˚F. Firstly, place the patient in a supine position with the legs raised above the heart. Next, assess their mental status - can they tell you what happened? Why did they collapse? How do they feel now? Any medical problems or medications?


Assess their fluid status - did they collapse 2/2 dehydration? Are they vomiting? Thirsty? Sweating? Flushed? Poor skin turgor? Sunken eyes? Hypotension? Tachycardia? If they seem okay other than being dehydrated, make moves to properly hydrate them in a safe area, in the shade and in an observed setting for a while to ensure their safety prior to discharge (they should probably not continue the race). 


If they are altered, you’re on a different pathway. What’s one of the first things we do in patients with AMS? ABCDE and F! For fingerstick - check that BGM, they may just need a snickers. If this is normal and they are altered, make moves to get them to the medical tent and likely transport to the hospital. They may have something more serious than simple dehydration and overexertion like electrolyte derangement, of which the most common in these races is hyponatremia.


Hyponatremia

Your patient is normothermic, but altered with a normal BGM. They look sick, they are vomiting, they may have some edema and you notice crystalized salty sweat stains all over them…consider hyponatremia.


In some setups in the field, you may have access to an EPOC or point of care electrolyte test. If you do, use it! If they have normal sodium 130-135, consider just giving them oral salt. Crack open that raw can of Campbell’s Chicken Noodle Soup and have them go to town on it (people actually do this intentionally in long races - yuck!). Restrict their water intake. If they tolerate this, check the sodium, vitals and mental status again in 30 minutes. If they don’t, then it’s time to level up!


This seems wild to me, having never even given this in the actual in-hospital setting, but you should consider a bolus of 100cc 3% NS (hypertonic saline). Remember that most people we see in the ED with hyponatremia have been chronically like that, these athletes were presumably not altered or hyponatremic prior to that starting gun going off (albeit a little cooky to run so far) - the point is, we can reasonably assume that this is a case of very ACUTE hyponatremia and so it makes sense to have a lower threshold to give them that corrective bolus. Monitor them closely - did this make a difference? Or did they get worse? Consider re-dosing and transporting to the hospital.


Hyperthermia 

Hyperthermia is defined as a rectal temperature >104˚F and comes in 2 sort of flavors or intensities: heat exhaustion or heat stroke. What’s the difference? Mental Status.


You can be hyperthermic without AMS, and as you may have guessed, heat stroke (hence AMS) is considered more serious than heat exhaustion. The extreme temperatures cause nervous system dysfunction and that needs fixin’ and QUICK!


Begin rapid cooling using whatever you have in the field - ice bath, evaporative cooling with misting and fans, cooled IV fluids.


If the patient cools to a normal human temperature compatible with life but remains altered, consider the other things already mentioned - hypoglycemia, hyponatremia and treat as needed.


Cardiac Arrest 

In the case of cardiac arrest 2/2 exertion, initiate ACLS as you would in the typical patient. Time is myocardium and brain and all those other things your professors told you. Consider that the aforementioned etiologies may be contributing and consider how they might alter your approach, but don’t delay chest compressions and other ACLS protocols trying to chase something else.


Welp, I hope you learned something and feel prepared to help the underprepared runners (and even those who’ve been training for months and have done this before!) in the coming weeks as they run silly distances on their silly little legs. I have to say it was very a cool experience to run with 22,000 other people on the streets of Brooklyn and see everyone cheering each other on and congrats to the many Maimo peeps who ran it on Sunday! We can do hard things!

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