Tag: medicine

time is the enemy: ischemia and infarction

In many wilderness medicine curriculums a core area of focus is distal CSM. Distal being “away” (in this context from the heart) and CSM being circulation, sensation, and movement. Blood and nerves tend to be wires hanging out in the same conduit throughout your body, collectively known as neurovascular bundles. Slice one and the results are clear: blood pours out and everything south of the severed nerves now has no feeling and muscles don’t work. Pretty terrible. Definitely something to avoid.

nvb
The yellow and red stuff makes it so you get blood, can move muscles, and feel things. You generally don’t want to have that get trashed.

In wilderness medicine you additionally have to deal with those neurovascular bundles getting pinched or squeezed. Even something as common as a dislocation, definitely something with lots of trauma (like a fall) that jammed a bone into some weird position, can now be putting sufficient force on blood and nerves that it went from a nuisance problem potentially life threatening.

In search and rescue, time is always against you. Consider a typical situation:

  1. Someone slips on a rock when backpacking and plants their next foot into a hole, bending their ankle in a way that baby jesus never intended it to move. It’s now 0800 just after breakfast.
  2. The patient tries to move around a bit and see how bad it is. Yep, it hurts like hell. They confer with their friends and decide there’s no way they can walk out. They need help. It’s now 0815.
  3. The friends get to a mountaintop where they can get a cell signal out and call 911, explaining the situation. It’s now 1130.
  4. Search and rescue gets mobilized and a helicopter is put on alert status. 1140.
  5. SAR is staging at the trailhead a few miles from the patient, packing the right gear. The helicopter has been re-assigned to a case of massive head trauma. No chopper today. 1200.

I’ll stop there as even before the first boot step moves in the patient’s direction four hours has already elapsed. You can chop that time down by having a $250 satellite communicator (and $15/month service plan), but it’s still going to take a while for folks to get to that patient and really this article is written towards the folks providing that medical care.

DelormeInReach
My preferred satellite communication device these days. GPS, bad-but-useable text messaging, tracking with a map folks at home can see, an SOS feature, and a good amount of battery life.

My training has taught me that infarction (tissue death) happens within about two hours. It’s not the same for all tissues, but for the arms/legs/hands/feet I go with 120 minutes. Pinch that blood supply off for that length of time and the tissue distal from it is deader than Firefly.

Fortunately ischemia (restriction of blood flow) is typically not an all-or-nothing thing. A bone jammed up against a tube of moving blood might block it a little, a bit, a bunch, or entirely. Think of having a plastic bag over your head versus one with a small hole in it. With the sealed plastic bag, you’re pretty dead pretty fast. With the small hole in, you can eek out a few more moments of life. The more restriction, the bigger the problem. So maybe you’ve got more than two hours since the ischemia might not be so complete. That’s hardly wonderful news since rescue response times can be all over the map with “a few hours” being optimal if the patient’s position is known, authorities were alerted immediately, and the terrain is not too difficult. If a patient’s location is unknown, response times to the tune of days is not uncommon.

And then you have transport time, which of course is wildly dependent upon terrain, the patient’s injuries, available air assets, and the size and ability of the ground crew.

Time is the enemy in other ways as well. Hypothermia in some climates, hyperthermia in others. Increasing intracranial pressure, HAPE, HACE, and a host of other problems get worse the longer they are left untreated. And generally by the nature of the operation you can assume they already have gone untreated for a prolonged period of time. With some exceptions, a properly trained wilderness medical provider can slow or even reverse many of these life threatening conditions.

litterlower
There’s nothing easy about transport.

By constantly remembering the impact of time on our patients, both before we got there and after they are in our care, we can do several things:

  • Shorten the list of serious problems that higher levels of medical care need to focus on. Instead of clinical¬†moderate hypothermia, a patient now might simply want a second blanket on arrival to the hospital due to your interventions.
  • Save a limb. The next time you hug a loved one or stand on two feet, imagine not being able to do that quite so easily. By ensuring proper perfusion our patients can fully live out their lives.
  • Provide more insight to higher levels of care. If our attempts at providing perfusion are inadequate (perhaps through manual alignment in accordance with your training and agency protocols), it’s a clear signal that other issues such as acute compartment syndrome might be at play.
  • Slice and dice between the the original chief complaint (an unstable and painful ankle) and new issues such as dehydration and heat illness from laying in an unshaded spot because of the ankle.

One way that time can be somewhat of your accomplice if not outright friendly:  keep track of things you may want to do during transport and execute them when appropriate. If a belay needs to be rigged, take some vitals. If the litter team is scouting a route, toss in some more heat packs.

And although an entirely separate conversation, haste can also be your enemy. Rigging a belay takes time, but is obviously better for the patient than chucking him or her down a cliff. We want to move fast, but only as fast as safety and the patient’s interests will allow.

Going back to the example of the injured ankle, if the ground team gets there at nightfall and a storm sets in, if perfusion isn’t an issue and there’s no immediate need of extraction would be it safer to set up camp for the night, wait out the weather, and then proceed with daylight and dry footing 12 hours later when potentially more rescuers are available as well? That’s a very big question and can’t be answered in a hypothetical: much more information is needed that only a real scenario would be able to address. I only bring it up to to balance against rapid transport as a rule, rather than a probable option.

My writing is commentary on my training and personal experience. I try as often as I can to discuss patient care with medical teams I interact with in order to learn where I can improve and provide better outcomes. Please don’t substitute my writing for comprehensive and recognized medical training.

 

 

WFR vs WEMT (Wilderness First Responder vs Wilderness EMT) for search and rescue

As I study my WEMT material, I’m pondering the differences between the two courses thus far. Currently a WFR, I’m headed up to Alaska in the fall for a multi-week WEMT course. Sleeping in a bunkhouse with my other classmates, on a somewhat remote Alaskan island (population 741), I’ll have 8am-8pm class 6 days a week, in addition to the months of material I’ve had to go over in advance (doing it now) and the WFR I needed just to register.

 

I started writing a whole primer on the various levels of wilderness medicine but I deleted it all as the topic is huge. Instead, I’ll try something new and focus on the title: WFR vs WEMT, specifically for search and rescue folks.

study
WFR is the books on the right. WEMT is the books on the left *and* the books on the right.

WildernessFirstResponder

Coming in with roughly ~100 hours of training is the Wilderness First Responder, or WFR, pronounced “woof-er”. This swiss army knife of wilderness medical response is the expected level of quality sar team members and outdoor guides need.

  • Laser beam focused on the task and environment. You’ll learn nothing about ambulance gear because hey: there’s no ambulances in the wilderness.
  • While still a multi-week time commitment it’s possible for most normal people to figure out a way to pay for it and take the time off.
  • Available in a lot of parts of the world.
  • Fairly uncomplicated focus on critical system stability. Identify and treat the things that are field manageable, identify and prioritize transport for the things that need higher levels of care.
  • By being able to dismiss the urban setting and ambulance (or better) equipment, things get simple pretty fast.
  • You are not operating under an agency’s medical direction so your protocols (reducing dislocations, clearing spines, administering epinephrine, stopping CPR, and declaring dead people dead) is actually much more than an EMT would be able to do provided you’re in a wilderness context (typically defined as two or more hours from definitive care).

wemtpatch

Coming in with roughly ~200 hours of training (tack on another 100 for the WFR you generally need to take the course) is the funky WEMT or EMT+W. It’s basically an EMT+B with special focus given to non-ambulance gear and prolonged care and life support in an austere environment.

  • You can have way more patient exposure if you want it. As an EMT-B you can be treated like shit and underpaid riding around in ambulances with horrible working hours. But hey, it’s work and more importantly it’s experience.
  • On a SAR team you’ll probably be the, or at least one of, the primary medical providers as WEMT is a rare designator that few people trot around with. Again, experience.
  • You can expand your reach by riding ambulances, joining (typically smaller) fire agencies, and even working in hospitals or at a local physician’s office.
  • With all that experience, you can move towards being a paramedic (EMT-P) if that suits you and you have the time/money.
  • You’ll understand more of what’s going on with your patients at a physiological level and have a broader understanding of chronic and acute disease.

The real benefits for WEMT comes down to experience and advancement. Working as an EMT-B sucks for most people. You’ll make roughly $12/hour, which is what I currently pay my babysitter and she sits around watching Netflix not dealing with death around the clock. Even paramedics make roughly $17/hour, and that’s after spending $10,000 – $20,000 to go to paramedic school and after having worked as an EMT making peanuts long enough to get the experience to even apply to paramedic school.

All that being said, your ability to gain experience and advancement as a WFR is basically zero, strictly from a medical perspective. You’ll be limited to the patient contact you have in SAR which can be pretty thin. Also, you’re hogging it and not letting others on your team drink from the firehose that is the primary medical provider role.

It was explained to me when I got my USCG Captain’s License: this means you can do the job, you don’t get good at it until you’ve done it a lot. When you first get your driver’s license you’re a terrible driver. It’s the years of driving experience on top of the license that make you decent. The same goes with all skills including medicine.

Captains with a license but not a lot of time running commercial ships are referred to as “paper captains” on the waterfront: it’s not a term of endearment. Whether it’s driving a car, flying a kite, or diagnosing hypovolemia you are better at it the more you do it.

wemt
Typical SAR work. You’re a long way from an ambulance.

Search and rescue is basically an all volunteer system, as it always has been. Going back to 1000AD, search and rescue is a side gig. And in a big way, that’s what makes it so great. Everyone is taking time away from their families, taking time off work, and prioritizing helping others. I heard a joke the other day that to get into sar you need to take the psychological test, and fail it. Getting a chance to work with these outstanding people is a privilege. And of course it is a privilege and not a right to treat a patient when they are in one of the scariest moments of their life.

Everyone in sar needs to make the decisions for themselves as to how far “good enough” is. Perhaps because I’m a bad climber, middle of the road tracker, and crummy mountaineer I think my medical skills are where I can do the most good. It’s not lost on me that my own daughter’s life was saved by a sar team’s medical chops.

If you’re a WFR and keep your skills sharp, I’ll work with you anytime. I’ve seen firsthand a WFR keep someone alive for hours in a jacked up situation before evacuation could occur. If you’re a WFR and want to get more time with patients and perhaps go onto other aspects of medicine short of nursing or doctoring, consider the WEMT route.