Strategies For Wilderness MedicineBy Gordon Benner, M.D., Outing Committee Medical Officer
These articles are reprinted with gracious permission from Inside Outings, the newsletter for Sierra Club leaders
[Dr. Benner's articles in this publication are written for use by Sierra Club leaders, in wilderness settings. Requests by other individuals or organizations to use or copy the material contained therein should be addressed to Dr. Benner c/o Inside Outings.]
Wilderness First Aid kits
Cold Weather Strategies
In Praise of Walking Sticks
Take My Pulse, Please!
Some Like it Hot
The Bear Problem
Sierra Club trips use a variety of first aid kits, and despite years of working on them, we've never found the perfect kit. There always seem to be items you never use and things you absolutely need but aren't there. That will probably always be true to some degree, but we keep working at it, trying to come up with the most appropriate kit for the specific trip.
I'd like to try a little thinking exercise here to help you come up with your own kit list, or to better understand the kit you already have. We're going to start out, not with the kit itself, but with the medical problems that lead us to use the kit. Try to imagine all the possible medical problems that could occur on your trip. You might start by listing all the problems that have occurred on your trips, or all those nightmare stories discussed in your subcommittee meetings. As a reminder, I'll list the Outing Committee Policy on first aid care on trips.
We should prepare for:
- Treatment of minor bruises, sprains, and skin trauma.
- First Aid Management, including splinting, of major sprains and fractures.
- Evaluation of medical problems which may require evacuation and medical care.
- Techniques of transportation and evacuation of the injured or ill patient.
Now, for each medical catastrophe you've dreamed up, ask yourself two questions: What am I going to do? and What equipment or supplies do I need? If you don't have a clue to the first question, you need to take a course quick, or if you don't, admit right off that you may need to seek advice from some trip member who might help.
Now, in your imagination, go through the first aid steps and list the equipment or medication you want in order to handle that catastrophe. You'll probably start thinking, "Hey, wait! This doesn't work. There's lots of stuff I want, but I don't have it all." That's exactly the exercise you have to go through, stimulated by the imaginary catastrophe in front of you, to decide what to put in the first aid kit. What do you want, versus what do you need, versus what do you really need, versus what do you really absolutely need and there is no possible substitute? How heavy is it? How big is it? How expensive is it? How perishable is it? Is it possible to bring it in a first aid kit?
Let's go through one example. A trip member has fallen, landed on an outstretched hand, and now has a painful, swollen wrist. He can move his fingers okay, but can't really use the hand because of wrist pain. Could it be fractured? Sure, but you really don't care because it's not going to affect what you do. Giving it some support with a splint would help control pain and prevent further injury. A moldable SAM splint would be great. If you are planning for a trip to Nepal, you might think that the splint would fit okay in the first aid bag and that a porter is going to carry it, so let's bring it. On a Sierra Club Knapsack trip, you think it's a bit big for the small first aid kit bag you're going to use. So could you do without it? How about cutting a couple of strips from an Ensolite sleeping pad? That's pretty stiff and could provide good support. If everyone turned out to have Thermarest pads, maybe you could just wrap it in your extra wool shirt and stiffen it up with some willow sticks. That will do okay.
Now the Nepal leader may be thinking, "Hey! We've got Ensolite pads, or the porters are carrying lots of cardboard boxes, and several layers of cardboard could make a dandy splint. So let's leave out the SAM splint." So now that you've got an improvised splint, you need to wrap up the arm in it. You could use bandanas from trip members. An Ace bandage would be easy. It's pretty light, compact, and (most important) has many other uses. Let's bring one.
So now, the victim has his wrist stabilized on a splint, wrapped in an Ace bandage. He's still complaining of pain, and may not get much sleep tonight. You could say, "We don't have anything for pain in our kit. Tough it out tonight and we'll get you to a car tomorrow." Or you could say, "We have some Advil and some Tylenol. They might help. Would you like to try some?" Or you could say, "We have some prescription codeine pills. They're stronger than Advil, and if you're not allergic to them, they might help you get a night's sleep. Would you like to try it?" Your comfort level in this situation will determine what medication you want in your first aid kit.
This example has been a bit long and wordy, but I hope it indicates the thought process that has to go behind every decision about what is in your kit. I'm going to leave it at that for now, and let you imagine other scenarios and responses. I'll have some other suggestions for kits in future articles.
On a related matter, Sierra Club first aid kits often contain outdated medicines. This has led to anxiety in leaders, who wonder if they are breaking the law, or could be sued for providing them. Replacing outdated pills involves some expense as we try to keep kits more or less up to date.
I have followed an informal practice of not insisting that outdated medicines be discarded. The practice was not based on hard published data, but simply on my feeling that the medicines were still useful, that discarding them was an unwarranted expense, and that I was unaware of any negative legal or medical consequences of using them. In July 1996, an article in The Medical Letter was published on this subject. It indicates the lack of hard data in this area, and it suggests that although some potency may be lost with time, it is extremely unlikely that outdated medicines pose any toxicity.
It is true that there are some medicines where dose is critical and blood levels are monitored. These tend to be long term endocrine or cardiac drugs (e.g. insulin, thyroid, digoxin, coumadin)... not the usual drugs in our first aid kits. The effective dose of antibiotics is broad enough that some loss of potency is extremely unlikely to have any consequences in the situations in which we would be using them.
It's still impossible to give an exact rule on when pills should be discarded; judgment must be made considering the physical condition of the pill and the specific medicine involved. The bottom line is: Don't automatically discard outdated pills, and don't worry we're doing something wrong by keeping them.
With cold weather coming on, and anticipating ski trips, I began thinking of cold weather medical problems, and soon came up with a pair of paradoxes: burns, and the inappropriate timing of this article. Hang in there; I'll explain.
Hypothermia is the classic risk we associate with cold weather. This refers to a gradual cooling of the body's core temperature in situations where heat loss to the environment is greater than heat production in the body. As this happens, blood circulation to the periphery of the body (generally the extremities, skin, and subcutaneous tissue) is diminished by diverting warm blood flow to the more vital core (heart, lungs, liver, kidneys, and brain). By sacrificing or cooling off the periphery, the temperature differential and heat loss to the environment are reduced. As core temperature falls, early symptoms are a sensation of being cold and the response of shivering. As body temperature falls below 93 degrees F, shivering stops and we no longer feel cold. Gradual mental confusion creeps in, muscles stiffen, our balance fails, judgment is lost. At 90 degrees and below, mental function is severely impaired, and unconsciousness soon follows. Cardiac arrythmias and heart failure lead shortly to death.
I'd like for a moment to focus on the earliest stage of hypothermia (actually pre-hypothermia) when perhaps the core temperature is still normal, but the body has begun to respond to loss of heat by reducing blood flow to the periphery, specifically the extremities. Our fingers and feet just don't move right. Here we are susceptible to injuries not usually directly associated with cold,such as sprained ankles or falls with more severe injury, which are really the consequence of impending hypothermia. With clumsy fingers, we hastily pitch a tent, crawl in, and try to fill and start a stove, resulting in spilled gas, a fire, and a burn. Or if you have a safer butane stove, you get the water boiling, then clumsily tip it over, causing a burn. The point, and first paradox, is that burns may be the consequence of impending hypothermia.
How about treatment of hypothermia? Over the years I've developed four steps for treatment, once you've recognized a problem. I admit these are based more on reading and reflection than on extensive experience. However, I believe that they are practical and applicable to the wilderness setting without any specialized equipment.
Step 1: Prevent further heat loss. This is the big one, the tough one, that has to be done as quickly as possible. This takes no medical expertise, but all of your wilderness skills. Get shelter, out of the wind, get wet clothes off and dry insulation on, get a tent up, dig a snow cave. Whatever, get to it! Know that if you don't succeed in this step, the game is lost.
Step 2: Relax. Take it easy. Assess the situation. Treat the victim very gently. Don't just do something, stand there! In the hypothermic body, everything is going very slowly, sort of a metabolic icebox. If you've accomplished the first step, you have time.
An important part of this step is to NOT take the victim's pulse. You may not feel it, either because it may be extremely slow, or just very hard to feel because of reduced blood flow to the periphery. And if you don't feel it, you may feel compelled to start CPR with chest compressions. This, I am convinced, is a mistake in hypothermia in a wilderness setting. In a truly pulseless cold victim, CPR is likely to be much less effective on a cold, stiff thorax. But more important, you risk converting a slow, weak pulse to a fatal ventricular fibrillation. Without the facilities of an emergency room (or perhaps of a helicopter), you simply can't manage any heart complication. Leave it alone. This approach is accepted by some professional mountain rescue organizations whose training, level of expertise, equipment, and accessibility to imminent helicopter rescue is much more favorable than your situation is likely to be.
Step 3: If the victim can swallow, give warm sugar liquids. It's a big IF. Someone can swallow a sugar liquid when 1) they can talk to you, 2) follow commands, 3) swallow their own saliva on command, and 4) swallow a small sip of water without choking. Clearly, here we're talking about mild hypothermia. The main point may be to recognize that, especially in exhaustive hypothermia at the end of the day, the victim may be hypoglycemic (short of sugar), and needs the calories more than the calories in a hot liquid. You can not heat someone up by having them drink hot liquids, but if their own metabolic furnace is stalled by lack of fuel, you can correct that with food, mainly sugar.
Step 4: If the third step doesn't resolve the problem, the next step is to arrange for rescue and evacuation, and heat the victim up. To focus on heating the victim up, remember to do things gently, slowly. Unlike heat illness, where every minute at high temperature cooks proteins like a hard boiled egg (Seven minutes and you're done), the body can stay in a metabolic icebox of hypothermia for hours before gradually warming up. Put hot water bottles in the sleeping bag, continually replacing the bottles as they cool off. Place them wrapped to prevent burning in areas where blood flow is near the surface, e.g. the neck, armpits, and groin. These areas are somewhat concave, and thus sort of fit a water bottle.
What about the scalp? We know its an easy place to lose heat because of the high blood flow. Can we reverse this and get heat in? Here's an oddball suggestion, untried, I'll admit: The convex water bottle doesn't make much contact with the convex skull, so try putting hot water in a ziplock bag on the scalp. Or for something with a higher specific heat capacity, how about oatmeal (or other food) in a plastic bag draped over the scalp. The point here may be that your best way of generating heat is your cooking stove. You can't expose the victim directly to flame, and putting several stoves in a tent to heat up the air risks carbon monoxide poisoning. The safest way is to transfer cooking heat to water or food, and transfer that to heat the victim. You can figure it out.
In many texts on hypothermia, a great distinction is made between mild and severe hypothermia, with a dividing temperature of about 90 degrees. Above this, victims generally recover if heat loss is stopped; below this, external heat must be supplied and a full rescue effort is needed. With this distinction, a low-reading thermometer (i.e. one that can read less than 94 degrees, not generally available in pharmacies) is often advised. I think in the above steps, at Step 3 the case is going to become obvious as mild and resolving, or severe and needing Step 4. I donıt feel a low-reading thermometer is necessary.
Finally, what's the paradox about the timing of this article? In winter, we think about cold and prepare for it better. The real danger is on those summer trips when an unexpected storm catches us unprepared, or after an accidental spill in cold water. Hypothermia is an ever-present year round concern.
Lately, I've taken to using a hiking stick. Years ago I considered the use of one as either an affectation of enthusiastic Austrian hiking groups, or a sure sign of an old wimp. I've never been an Austrian, but I guess I may be an...... or getting there.
Hiking sticks are definitely not the norm. I get odd looks and comments ranging from, "Hey, neat stick!" to "What's that for?", and "Why do you need that?"
One of my hiking sticks is the remnant of an old bamboo ski pole with an 8" basket. The basket and original wrist strap has long since disintegrated, but the metal point is still good, and a new nylon wrist strap serves the purpose. I also use a pair of standard cross country adjustable ski poles.
One can always pick up a walking stick along the trail, and you may have found your favorite this way. Too often, I find, I can never get the right stick when I need it, and of course it doesn't have a wrist strap.
Why use a walking stick at all? I guess the two basic reasons are, first to propel yourself along using arm power in addition to leg power, and second to aid with balance and prevent falls. On an even, level trail, neither of these is of much import, and many people will find the stick a nuisance. Here is where a lightweight collapsible ski pole that will fit in your pack tends to shine. Going uphill, you can get a push from your arms with the stick. However, your rate of climb is often limited by your overall aerobic capacity, rather than leg strength alone, so spreading the effort to your arms isn't going to help that much. Going downhill, you can definitely stabilize yourself with a stick... more so on a loose rocky slope than a well packed trail. And for stream crossing? A third or fourth point of support can make all the difference.
Do hiking sticks actually prevent falls? Not much hard science here, but there is one report from the Alps. One-hundred ninety-two hikers who used sticks were interviewed and compared to a similar group that did not. A similar number of "stumbles" occurred in both groups, but there significantly fewer "falls" in the group using sticks.
One stick or two? In those easy places where one stick is a nuisance, two will be a double nuisance. However, when really needed, two sticks are much preferred. The Medical Commission of the International Union of Alpine Associations has recommended this, but admittedly, in practice, it's the exception.
There are a couple of circumstances where walking sticks become and important part of your medical kit, rather than just an optional hiking gadget. If somebody does twist an ankle or knee, the use of two adjustable sticks may make a major difference in mobility along the trail. Another circumstance arises when one member of your party is weak or limping, and really in need of support along the trail. Walking beside someone, perhaps with his arm over your shoulder, is very unsatisfactory, since it usually puts the supporting person off the trail. A great support method is to put two support people on the trail, one in front and one behind the victim. The support people hold two sticks horizontally, one in their right hands, one in their left. The victim walks between them, holding on to these hand rails, surrounded by them so he can't fall off the trail.
This is, after all, supposed to be a medical column, so I have to find some medical relevance for two walking sticks. There it is, and in any group hike, I like to see two walking sticks in case the need arises. I hope you find them as helpful as I have.
When confronted with some medical emergency in the wilderness, either an accident or illness, it is natural to feel bit overwhelmed and inadequate, and wishing you were just outside a well equipped emergency room, or where a 911 call would bring a well-stocked and well-staffed ambulance. We have images in our mind, either from our own experience or from some TV show or movie, of a victim being wheeled in on a stretcher while medical personnel pounce on him with a variety of wires, gauges, and sensors to monitor his condition to find out what's going on. In a wilderness situation, we obviously don't have all that high tech equipment, and so we feel at a great disadvantage in trying to practice what medicine we can.
In the real world, however, the initial contact between the medical system and a patient is not that high tech at all. It involves a quick assessment of what are called the vital signs, which include mental state, pulse, respiratory rate, temperature, and blood pressure. These are the the first thing that a doctor looks for, either in the emergency room or on regular hospital rounds, and the most basic and best indicators of how a patient is doing.
Mental state is quickly determined by talking to the patient and seeing what he responds to. A simple grading scale might have five steps. The patient is: 1. Talking rationally, alert, and oriented.
2. Talking but confused.
3. Not talking spontaneously but responds to voices (e.g. follows simple commands).
4. Only responds to pain (moans or withdraws).
5. Not responding.
The pulse is a count of of heart beats per minute. It can be felt at the wrist or the side of the neck. If you can't feel a pulse at all, that's obviously a significant finding. A normal pulse will be between 60-80 beats/minute, although in some people a wider range, from 50 to 90, can be normal. We can usually count accurately up to 120/minute, but faster rates become more difficult to count, and we end up saying something like "over 130 per minute" or "too fast to count." A simple estimate of whether the pulse is regular or irregular is helpful. I am aware from my own practice that many people without medical training find it difficult to take a pulse, but it really is a simple basic skill that everyone in a position of responsibility on a trip should be able to do. Practice! Get someone to help you.
To count the respiratory rate, we need to hear the breath sounds or see the rise and fall of the chest wall. With a normal rate of around 10-20 per minute, it takes a longer count to get accuracy, and counting for 15 seconds and multiplying by 4 doesn't do it. Since respiratory rate can be modified voluntarily, you don't want the patient to be thinking about his breathing while you are counting. Pretend to count his pulse as you really count respirations,
The temperature we're interested in as a vital sign is the core body temperature, perhaps the temperature of the blood going through the heart. Since we can't get at that directly, the standard is the temperature under the tongue (with the mouth closed), which averages 98.6 F +/- 1 degree. We have to emphasize that this is different from the subjective sensation of feeling hot. Women in menopause have frequent hot flashes, but this is not a change in core body temperature. Even in a flu or respiratory infection, the sensation of feeling feverish doesn't always correlate with an elevated temperature. When evaluating people with infections, it is critically important to know if the temperature is normal or 104.
So far in our survey of vital signs, we've used three very high tech tools (our brain, eyes, and hands) and two relatively lightweight tools: a watch and a thermometer. For the final vital sign, blood pressure, we need a tool we probably won't have in the wilderness: a sphygmomanometer. We'll just have to proceed without bood pressure.
The important conclusion of all this is that, in a wilderness setting, with minimum equipment, we are able to make an initial evaluation on a par with what is done in the most modern emergency room or intensive care unit. If we fail in our evaluation of a patient, it is often often simply because we neglected to do the measurements we can do.
All good and well, you say. You understand what all those numbers mean, but it's still just confusing numbers to you. I agree entirely that interpretation of the vital signs is difficult, and beyond the scope of this article. But the usual context is one in which you may be deciding whether to call for a helicopter rescue a heavy responsibility. Rescue folks are highly dedicated, willing to make great efforts, and take some risks for a true emergency. We have to remember that occasionally helicopter accidents do occur. The decision to call for a rescue is not easy, and you need all the help you can get. The vital signs can support your decision either way. If the signs are normal, think twice about your reasons for calling for a rescue. But if I'm lying there with a pulse of 120 and a temperature of 103, just go by the numbers, and get me out!
Well, it's been a cool Spring and an early Summer in the Bay Area, but it's beginning to heat up, so maybe it's finally time to deal with some heat- related illnesses. An effective way to focus our attention on heat illness is to consider what effect hyperthermia has on the body by means of a little mental experiment with an egg.
My brother has chickens, and I recently had an egg fresh from under a hen, the yolk bright and yellow and the white not white at all, but a sort of mucoid translucent material that turns white as soon as it is cooked, which involves denaturing the proteins by heat. This egg is pretty much the same as the egg you get out of the refrigerator, which has been preserved but not changed much by its stay in hypothermic conditions. As an experiment, I heated a pan of water to 108 F (not really very hot) and cracked an egg into it. In three minutes the first wispy strands of albumin had turned white, and by 25 minutes the denser "white" around the yolk was beginning to turn opaque.
The point of all this is that, whereas biologic tissue can withstand cold periods, heat (even moderate heat) begins to denature proteins and cook them in a matter of minutes. When we get the flu, our temperature can shoot to 105 F, and we feel lousy, but we recover none the worse. But just a few degrees higher and we start cooking, and irreversible tissue damage occurs. Hyperthermia or core body temperature over 106, is a medical emergency. The appropriate response is to cool the body off as soon as possible.
Before getting into treatment, let's look at how the body tries to cool itself off to prevent hyperthermia. The two basic mechanisms are peripheral vasodilation and sweating. The first brings more blood to the surface of the body where it can be cooled by the environment. Clearly this won't do much good if the environmental temperature is higher than your body temperature, as it well may be. But the second mechanism, sweating, saves us. Sweat is not cool water on the surface of the skin, it is water and salts at our body temperature that evaporate. Evaporation is the real cooling mechanism.
Both vasodilation and sweating have the same effect on blood flow dynamics, namely low blood pressure. A larger vascular space and/or less fluid in the vascular system just results in low blood pressure (especially when standing), and [brings on] all those vague symptoms like wooziness, dizziness, lightheadedness, weakness, and just not feeling right. The treatment for all this is just what you would intuitively do anyway: lie the victim down, elevate the legs, head slightly lower than the heart, keep the person cool and out of the sun, and replace fluids as rapidly as possible. Ice cold fluids may taste good, but it's not the coldness of the fluid that really helps; it's just the volume that fills back up the vascular tree.
So far we've talked about physiology and what happens when people are exposed to heat. Let's look at some specific diagnoses. You will often hear about heat syncope (fainting), heat exhaustion, and heat stroke. In simplest terms, heat syncope is due to vasodilation, causing lower blood pressure. Exhaustion is due to sweating and fluid loss, causing lower blood pressure. Stroke is due to elevated temperature. Attempting to differentiate between these is, I believe, a waste of time, because they are all present to some degree in heat related illness. Vasodilation and some degree of fluid loss from sweating will almost always be present, and it is always appropriate to treat as in the above paragraph.
The important decision you have to make is whether the person is also hyperthermic. Here are some clues:
1. If you have a thermometer and can take the victim's temperature, you've got the answer. Remember our last digression on vital signs? Temp 105 F or higher; treat for hyperthermia.
2. Rapid pulse, perhaps 120 or faster.
3. Dry skin. This really points to a failure of sweating, and can occur if someone has sweated so much that s/he's run out of fluids, or is taking medications with anticholinergic properties that interfere with sweating. In the past, dry skin was a hallmark of heat stroke, implying that sweating was so efficient at cooling someone off, s/he wouldn't get hyperthermic unless there was a failure of the sweating mechanism. We now know that someone in good aerobic condition can exercise vigorously enough and long enough to get hyperthermic even with copious sweating.
4. Obviously, environmental conditions are key, i.e. hot weather, but especially high humidity, that will minimize the evaporative cooling of sweat.
5. Finally, neurologic deficits, such as persistent confusion or difficulty speaking after lying down, that indicate the brain is beginning to cook.
If you do suspect the victim is hyperthermic, you've got a medical problem on your hands. Cool the victim immediately. Expose lots of skin, douse with water, and fan vigorously to promote evaporation. Keep the victim wet and windy. Do all those things you avoided when fearful of hypothermia. A victim can't be cooled off by drinking ice water and may not be able to swallow anyway. The amount of cooling in a couple of quarts of ice water is not significant. You need evaporation on the skin.
Having emphasized the cooling power of evaporation leads to a comment on hot weather clothing. You often see people exercising in hot weather, bare chested just dripping with sweat. Remember every drop of sweat that falls off you is wasted. If it doesn't evaporate on the skin, the next best option is to soak into a light garment and let it evaporate near your skin. In hot weather hiking, if you reach a water source, don't hesitate to jump right in and soak all your clothes. You'll be dry soon enough, and all the cooler for it.
In summary, with heat related illnesses, always treat for fluid loss, volume problems, and low blood pressure. Your big, difficult decision is whether the victims are hyperthermic. If so, treat vigorously. All hyperthermic victims need evacuation from a wilderness setting because residual kidney or liver damage may not be apparent without testing.
Perhaps too much has already been written about bear problems in the Sierra. With apologies, I offer a bit more.
The traditional advice has been to hang your food high in a tree. If a bear threatens, be a little aggressive, make noise, perhaps throw rocks, let that guy know you still think you're the boss. Some ingenious methods have been devised, some by Sierra Club leaders, of getting food up in the trees, and this overall strategy seemed to work for awhile, and. human injuries from bears were practically unheard of.
But in the last two summers, there have been two injuries to humans from bears, serious enough to require prompt medical care. In both cases, there was no unprovoked attack by a bear; the bear was after camp food, and the human was in the way. Both incidents occurred in the same general area at the head of Bubbs Creek in the Sierra, and perhaps this is an aberrant experience with a single bear that will never happen again
The point is that we have a strong reminder that the most important thing out there is not our food; it's our safety. We cannot count on the bear backing down. In one incident, a bear did seem to be at a safe distance, when a second bear did the damage before its presence was fully appreciated.
Bears are smarter at getting food in trees, and if we depend on that method, it will be a battle that I think we will lose. There does seem to be universally good reports with bear canisters, and backpackers may just have to bite the bullet and accept the extra weight. Bear boxes are available in many places in the Sierra, so finding out those locations when you get your wilderness permit can be critical. For stock trips, there are bear-proof packing boxes. Some backpackers have been sinking a food container under water at night. You can often find a deep crevice in a talus pile where a food bag can't be reached by a bear, although it be may be nibbled by small creatures.
In summary, we need to use all our wits to find effective ways to store food away from our tents so we can enjoy a safe, good night's sleep.