>The 2014 Mt Rogers Hangout planning forum:
Well, it’s that time again, the 8TH annual Mt Rogers Winter hangout to be held at the Grayson Highlands State park group campground on January 17 – 19. 2014. The oldest Cold Weather campout for Hammocks!
LET THE PLANNING BEGIN!!! WOO HOO!!!!!
First the important stuff like: FOOD & Raffle stuff. There is also the option of day hikes & what to do if you get there early, like on Thursday the 16th.
This year (2013) to do any serious hiking after about 1500 on Thursday required snowshoes, so that is something to consider. HOWEVER, 2011 was the first time snowshoes were seriously needed due to the depth of the snow, especially when it was in drifts.
AND, last year (2012), “warm” weather & a pretty constant rain.
An important note: BRING AT LEAST ONE SPARE PAIR OF BOOTS FOR AROUND CAMP! Just in case your “Primary” shoes/boots get wet! If you can, bring a pair that is a size or 2 too large for you, (I wear a size 9, my Highland hang camp boots are size 12s) this allows you to wear an extra pair of socks or 2 & allow for a chemical heat pack in each shoe.
Reminder; this is NOT a hammocker only event! Tents are welcome, as are any other “Groundlings”. In fact, I can safely say; if someone wants to build (& sleep in?) an Igloo; that would be GREAT & enthusiastically viewed by all attendees. (This is a subtle hint by me. Well, as close to subtle as I get.) So far we have had several tents at the MRHO over the past 7 years & they were welcomed heartily. OK, so we pointed & laughed at them a few times, doesn’t mean they weren’t welcome.
Food: On Saturday (starting at around Noon or just after) is the “Pot luck dinner” where everyone brings that special food item to share around the campfire. The rest of the time your food is up to you. A new tradition was started this year, so I’ll be bringing Scotch eggs for a snack around the fire on Friday. Please note that 6 of the 36 I plan on bringing will be spicy! Leftovers, if any, will be served Sat.
Raffle prizes: Every year just after the Potluck dinner, there is a gear Raffle for the attendees. Donations are accepted, preferably something new(ish) & nice. Hammock related items are usually the focus, & cold weather camping gear is always appreciated. Many use newly won quilts, or clothing that night!! DIY stuff is also encouraged. Tickets for the Raffle are $10.00 each & the proceeds go toward: rental of the Group campsite & shelter, rental of a “Porta Privy” from Jobsite Johnny with the leftover funds donated to the park. So dig deep for the chance to win big & support a great organization.
Camping: We are at the group campground & amphitheater. During NORMAL times of the year, that would mean we have to stay IN the Group area ONLY! But as we are the only ones here during the winter (“Crazy enough to camp in this weather”) we can pretty much spread out as much as we want to. We have been asked to please stay (camping wise) E of the amphitheater & S of the Road / parking lot. There are AMPLE trees in the area & minimal ground cover to worry about. There is parking for (by my estimation) about 30 cars at the Group Campground, & so far we have never filled those spaces.
ALCOHOL CONSUMPTION: is not allowed in the park. Sorry! And, the Rangers are INVITED to the potluck. 2 attended in 2011, so drink at your own risk.
Day hikes: OH MY! There are so many trails in the area.
is a map of the area. A few words of advice if you go on a hike: It is WINTER, & we are in the mountains. That means the weather can change VERY VERY QUICKLY!!! So, take a friend or 3, warm clothing & at least a lunch. An INSULATED water bottle is also important, &/or keep one inside your coat. Cell phone coverage in & around Grayson highlands is spotty at best; so DO NOT COUNT ON YOUR CELL PHONE IN AN EMERGENCY!!
After Event: On Sunday, many go to the Log House Restaurant about a 30 minute drive from the park for Breakfast / Brunch. Go Left out of the Park entrance. This year I plan on calling them again on Monday before to warn that we are coming, so if we could get a rough count by then, that would be great!
General information on the hangout: It will be cold, it may be VERY cold!! It will be windy, it may be VERY windy! It may snow, & it may snow A LOT!!! It may also rain, yes even at below freezing temps!! In those conditions, the rain freezes as soon as it touches almost anything, even you. And, as mentioned above, it RAINED a lot in 2012, (& Thursday in 2013) so no matter what the weather people say, bring rain gear! A suggestion that was VERY important to us that came 2013 on Thursday.
If you have ANY questions about cold weather camping, feel free to ask them now or at the hangout. If you have ever wanted to try winter camping but, like me were afraid to try, this is the time to do it: we are in a relatively safe area, with quite a few very experienced Cold Weather hangers so help & advice is readily at hand. I will likely repeat this several times before the actual event, but please remember: IF YOU NEED HELP, ASK SOMEONE!! IF YOU GET TOO COLD AT NIGHT, WAKE SOMEONE UP FOR HELP!! Do NOT “tough it out” Hypothermia is a bad thing!! Also, the cars are close so can be a good place to warm up if you need it, if you rode with someone, be sure to know where they are camped & go ask for the car keys. Or better yet, if someone rides with you, be sure they have a key too!
I will NOT mind if you wake ME up because you are cold!!!
Regarding car keys, bring a spare set or 4 & put them somewhere on you &/or your car just in case you get locked out with the keys inside your car.
If you are unsure that your insulation is set up properly, ask one of the “Old timers” for a pointer or two. This saved my trip during the first MRHO (Thanks Pan!) & can save yours!! Good insulation, installed / used poorly can mean a cold night.
Chemical hot packs can make a BIG difference!
You may have heard this phrase used a lot regarding real estate: “Location, Location, Location!” in Winter / Cold Weather camping it is CRITICAL. As mentioned above, “In some locations it got down to –2 degrees.” In other areas, within as little as 50’, it was up to 5 degrees warmer (Even allowing for differences in thermometers, pretty remarkable). Also, orientation of your tarp ACROSS the prevailing wind direction means a warmer night. Generally wind direction is from the West, but there are times when it will seem to be coming from all points of the compass at the same time (Thursday night 2013). Not kidding! As mentioned above, it can get quite windy so be prepared to stake your tarp as much as you can, now is not the time to skimp on ANYTHING!!
As the hangout is at the group camping area, we are close to the park road, which means you can bring extra anything (Food, insulation, etc.) to make life a bit easier. In fact, in 2011 there were 2 Coleman multi burner stoves, which made it nice for fixing some of the larger food items like chili & Jimbalaya. I suspect that some will bring firewood, if you do, please be sure it is not from a quarantined area (Emerald Ash Borer, Balsam Woolly Algid, etc). If you don’t know, find out before you bring possibly contaminated wood to the area. Thank you! For example, I would not be bringing firewood as my area is infested with the Emerald Ash Borer. Another note about fire: No matter how much you paid for which ever piece of gear, if you set it too close to the fire it will melt or burn if it’s made of the correct stuff. With the fire we had in 2011, stuff (like water bottles & shoes) sitting on the wall, 2’ to 3’ from frank fire, melted. Yea, it was a big fire.
Another “It bears saying more than once!” Now is not the time to skimp on ANYTHING!!
Thursday: I plan on hiking to the Wise Shelter for the night, provided it’s not RAINING.
Friday: IF I go to the Wise shelter Thursday & am feeling “Frisky” I may attempt a hike to the Scales & back. This is one of my favorite hikes in the area.
Now for the “Bad stuff!”
Remember a few things about food at a winter campout. It will freeze! Cooking times are MUCH longer! It will freeze once you cook it! Water is harder to come by, & it will freeze once you have it! High fat food means fuel for the furnace, this campout is NOT the time to be on a low fat diet. That being said, even Olive oil will freeze when the warmest the weekend gets is 20f. No, keeping it in your car will not keep anything from freezing, sorry. In 2011 it got to negative 2 in some areas, this means whatever freezes will freeze VERY solid.
EVERYTHING is harder to do in the cold. It is harder to move due to the amount of clothing worn AND due to the cold. Doing fine motor skills is hard with gloves on, & even harder without in sub freezing weather. Going to the toilet, even in a nice enclosed port-a-privy is, at best, an adventure. Along those lines: hand sanitizer will freeze, & baby wipes become useless in short order. I overcame that in 2011 by keeping both in an inside pocket. But at 17 degrees F or colder, you better use them as soon as you get them out or,,, well: BURR! Snow is pretty, but very hard to walk on / through without snowshoes. Even the stuff that is compressed on the trails to & from various “events” at the camp-ground it will take more energy than walking those same areas during warmer weather. A ¼ mile walk to the privy can feel like a ½ mile hike or more if the snow is really deep & the park service couldn’t plow the road.
WATER FREEZES AT 32 DEGREES FAHRENHEIT (Or 0 C) At below 0 F, it freezes VERY quickly! So do try to keep your water warm & insulated. A pocket or pouch INSIDE your coat to hold your water bottle can be a good idea. And outside pocket will not keep your water bottle from freezing.
So, anyway, a great time is always had; good food, good company, “bad” weather, you know, “Fun!”
Cold weather tips N hints:
Stay slightly cool to stay warm. If you get too warm you will sweat, if you sweat you are getting wet, if you get wet you will get cold. I have been known to get overheated at just about every cold weather hang out so have stripped to just tee shirt & pants (or kilt) just to cool off & not get wet.
Eat high calorie / high fat foods. Eat more than you would in temperate weather doing the same activities. Bear in mind that even just standing around the campfire talking you are burning a LOT of calories just to stay warm, regardless of your insulation.
A high calorie snack just before bed can help you stay warm at night. And a snack during the night (Perhaps after a trip to answer the “call of nature”) can help you stay warmer longer.
A few chemical heat packs kept handy can warm you up if you get too cold. HINT: Do not use BEFORE you get cold, they may get you too hot, thereby causing you to sweat & (as above) get colder. Also you can put a hot water bottle in your hammock with you, for more info on this go to http://www.hammockforums.net/forum/s...ead.php?t=6313
During the hangout, drink a lot of water! Dehydration can lead to an increased risk of hypothermia. Drinking warmed water (Coffee, Hot chocolate, hot Gatorade, etc.) can reduce the cooling effect of drinking cold water. And, much of the water available at the hangout is very near freezing temp. Personal note: As a rule, I do not get cold, ever, but at the 2011 hangout I did, after doing an AAR when I got home, I figured out that I simply had not drank enough. At least that is all I could figure out I did wrong.
Alcohol use will dilate your peripheral blood vessels (the ones in your skin) making you FEEL warmer, HOWEVER, this will cause you to cool off much faster, with the side effect of reduced sensation due to alcohol use that will not let you notice you are in trouble.
IF someone looks disoriented (much like over indulgence of alcohol) they may be in the mid to late stages of Hypothermia & need help NOW! They need to be warmed up quickly & without delay!
IF someone comes to you & says “I’m in trouble!” OR “I need help!” You do not have anything else to do but to help that person! NOTHING is more important right then! Go start your car, lead them to the fire, & help them get warm dry clothing, whatever it takes. WHATEVER IT TAKES! I was recipient of such aid in 2013, it was greatly appreciated.
IF someone comes to you & says “I think you are getting hypothermia! Let me help you!” listen to them. If it is true & you are hypothermic, you will NOT know it! If they force you to stop what you are doing & get in a car or other warm place, DO NOT GET MAD! You seriously need help.
IF you see someone that may be in hypothermia, get him or her to someplace warm. They may fight you, so be gentle yet firm. Once they warm up they will thank you!!
If ANYONE starts taking off clothing AND are incoherent, they are in DEEP trouble & it is now time for the group to get them to a warm place.
If he is coherent & taking off clothing, leave Doctari alone. Because once again he stupidly got overheated & is close to HYPERthermia. Yes, even if it’s well below freezing. Yes, if he don’t cool off quick enough he will pass out or at least throw up! Happens almost every year*, so why should this one be any different? *2013 was first year it didn’t happen.
IF you feel you are in trouble, regardless of the time of day, GET HELP! If you are shivering & can’t stop, regardless of the time of day, GET HELP! If you suddenly stop shivering, regardless of the time of day, GET HELP!
If someone wakes you up for Help, regardless of the time of day, GIVE / GET them help!! If someone wakes you up wake someone else up to help! At the average temperatures we have had over the years at Mt Rogers, Hypothermia can progress very rapidly. If you think someone is approaching hypothermia NOW is the time to act. And, get someone to help you help the person in danger! In 2011 the temps at least got close to ZERO, that is not the time or temperature to wait to see if they get better on their own.
In 2012 it Rained, a LOT, Prime hypothermia weather.
In 2013 it snowed, quite a bit, & it was a wet snow so EVERYTHING that touched snow got wet, plus it had rained for hours before switching to snow, so the ground was soaked! Also Prime hypothermia weather.
THIS BEARS REPEATING: IF SOMEONE OFFERS YOU HELP, ACCEPT IT!! IF SOMEONE NEEDS HELP, GIVE IT!! If someone needs help, GIVE IT QUICKLY!
If you have extra insulation for your sleep system, bring it with you. You don’t have to use it, but have it ready to deploy.
Contrary to what you may think, ventilation is CRITICAL to keeping warm. So do not fully seal your tarp or tent. If you have a hammock sock or similar (like a BBO or a full coverage 1X), leave it open for ventilation! Even fabric that is breathable (Yes even bug netting) can get sealed by your breath freezing on it, causing you to get “snowed on” & chilled OR (if woven tightly enough) even cut off the airflow.
Also, keeping your Top Quilt dry can be a bit, , , , challenging, especially by your head (Mouth n nose) from breathing on it. See Shug’s videos on how he reduces that with a small piece of fleece strategically placed.
Your camera may freeze / quit working. Your back up camera may also freeze. At times I can get about 5 quick pictures or about 15 - 20 ssssssseconds of video before mine said “ENOUGH” & shut down in 2011. Then other times it would work for 30 minutes or more. YPYM, YTYC*. And, if it rains, a waterproof covering or camera is a boon.
If it snows, or if it MAY snow: do not stake your tarp all the way to the ground. Leave a gap at least ½ the distance from the ground of the expected snowfall depth. If you do not do this the weight of the snow may well collapse your tarp around you. Leaving this “Gap” will allow the snow to fall off of your tarp. Also bear in mind that snowfall predictions from the weather service are for lowland areas, the snowfall up in Grayson highlands may be 2 – 4 times higher. A snow shovel will help you to dig out if you miss guess the gap.
DO NOT COUNT ON YOUR CELL PHONE IN AN EMERGENCY!!
DO NOT SKIMP ON ANYTHING! Extra clothing, extra food, spare shoes/boots, etc.
HELP THOSE IN NEED, ACCEPT HELP WHEN OFFERED!
STAY COOL TO STAY DRY, STAY DRY TO STAY WARM!
BRING AT LEAST ONE SPARE PAIR OF BOOTS FOR AROUND CAMP!
Disruption of the body's normal thermoregulation may produce cold-related disorders such as hypothermia, frostbite, & trench foot.
Hypothermia is a state of low body temperature, specifically low core temperature. When the core temperature of the body drops below 95� F (35� C), an individual is considered to be hypothermic. Hypothermia can be attributed to inadequate thermogenesis, excessive cold stress, or a combination of both.
Mechanisms of Heat Conservation & Loss
Exposure to cold normally triggers compensatory mechanisms designed to conserve & generate heat in order to maintain a normal body temperature. One such mechanism is piloerection (hair standing on end, "goose bumps") to impede air flow across the skin. Shivering & increased muscle tone occur, resulting in increased metabolism. There is peripheral vasoconstriction with an increase in cardiac output & respiratory rate. When these mechanisms can no longer adequately compensate for heat lost from the body surface, the body temperature falls. As the body temperature falls, so do the metabolic rate & cardiac output.
As discussed, major mechanisms of body heat loss are conduction, convection, radiation, evaporation, & respiration. Heat loss can be increased by the removal of clothing (decreased insulation, increased radiation), the wetting of clothing by rain or snow (increased conduction & evaporation), air movement around the body (increased convection), or contact with a cold surface or coldwater immersion (increased conduction).
Several factors can contribute to the risk of developing hypothermia. They also contribute to the severity of damage if cold injury occurs. Risk factors that increase the danger of developing hypothermia include:
· Age of the patient � Pediatric or geriatric patients cannot tolerate cold environments & have less responsive heat generating mechanisms to combat cold exposure. Elderly persons often become hypothermic in environments that seem only mildly cool to others.
· Health of the patient � Hypothyroidism suppresses metabolism, preventing patients from responding appropriately to cold stress. Malnutrition, hypoglycemia, Parkinson's disease, fatigue, & other medical conditions can interfere with the body's ability to combat cold exposure.
· Medications � Some drugs interfere with proper heat generating mechanisms. These include narcotics, alcohol, phenothiazines, barbiturates, antiseizure medications, antihistamines & other allergy medications, antipsychotics, sedatives, antidepressants, & various pain medications such as aspirin, acetaminophen, & NSAJDs.
· Prolonged or intense exposure � The length & severity of cold exposure have a direct effect on morbidity & mortality.
· Coexisting weather conditions � High humidity, brisk winds, or accompanying rain can all magnify the effect of cold exposure on the human body by accelerating the loss of heat from skin surfaces.
Certain precautions can decrease the risk of morbidity related to cold injury.
· Dress warmly.
· Get plenty of rest to maximize the ability of heat generating mechanisms to replenish energy supplies.
· Eat appropriately & at regular intervals to support metabolism.
· Limit exposure to cold environments.
Degrees of Hypothermia
Hypothermia can be classified as mild or severe, as follows:
· Mild � a core temperature greater than 90� F (32� C) with signs & symptoms of hypothermia
· Severe � a core temperature less than 90� F (32� C) with signs & symptoms of hypothermia
Initially some patients may exhibit compensated hypothermia. In this case signs & symptoms of hypothermia will be present but with a normal core body temperature, temporarily maintained by thermogenesis. As energy stores from the liver & muscle glycogen are exhausted, the core body temperature will drop.
The onset of symptoms may be acute, as occurs when a person suddenly falls through ice into a frigid lake. Subacute exposure can occur in situations such as when mountain climbers are trapped in a snowy, cold environment. Finally, chronic exposure to cold is a growing problem in our inner cities where homeless people endure frequent & prolonged cold stress without shelter.
In some cases cold exposure is the primary cause of hypothermia, but in others, hypothermia may develop secondary to other problems, such as medical problems. For example, hypothyroidism depresses the body's heat-producing mechanisms. Brain tumors or head trauma can depress the hypothalamic temperature control center, causing hypothermia. Other conditions such as myocardial infarction, diabetes, hypoglycemia, drugs, poor nutrition, sepsis, or old age can also contribute to metabolic & circulatory disorders that predispose to hypothermia. Any patient thought to have hypothermia, but with no history of exposure to a cold environment, should be assessed for any predisposing factors. Evaluate the patient for level of consciousness, cool skin, & shivering. Also, evaluate the rectal temperature. A rectal temperature of less than 95� F (35� C) indicates hypothermia. Key findings at different degrees of hypothermia are summarized in Table 36-i.
Patients who experience body temperatures above 86� F (30� C) will usually have a favorable prognosis. Those with temperatures below 86� F (30� C) show a significant increase in mortality rate. Remember that most thermometers used in medicine do not register below 95� F (35� C). EMS systems in colder areas should carry special thermometers for recording subnormal temperature readings as there is no reliable correlation between signs & symptoms & actual core body temperature.
Signs & Symptoms
Signs & symptoms of hypothermia are summarized in Table 2. Patients experiencing mild hypothermia (core temperature > 90� F or 32� C) will generally exhibit shivering. The patient may be lethargic & somewhat dulled mentally. (In some cases, however, they may be fully oriented.) Muscles may be stiff & uncoordinated, causing the patient to walk with a stumbling, staggering gait.
Table 1. Key Findings at Different Degrees of Hypothermia
C� F� Clinical Findings
37.6 99.6 Normal rectal temperature
37 98.6 Normal oral temperature
36 96.8 Metabolic rate increased
35 95 Maximum shivering seen Impaired judgment
34 93.2 Amnesia Slurred speech
33 91.4 Severe clouding of consciousness/apathy Uncoordinated movement
32 89.6 Most shivering ceases Pupils dilate
31 87.8 Blood pressure may no longer be obtainable
30 86 Atrial fibrillation/other dysrhythmias develop Pulse & cardiac output decreased by 33%
29 84.2 Progressive decrease in pulse & breathing Progressive decrease in level of consciousness
28 82.4 Pulse & oxygen consumption decreased by 50% Severe slowing of respiration Increased muscle rigidity Loss of consciousness High risk of ventricular fibrillation
27 80.6 Loss of reflexes & voluntary movement Patients appear clinically dead
26 78.8 No reflexes or response to painful stimuli
25 77 Cerebral blood flow decreased by 66%
24 75.2 Marked hypotension
22 71.6 Maximum risk for ventricular fibrillation
19 66.2 Flat electroencephalogram (EEG)
18 64.4 Asystole
16 60.8 Lowest reported adult survival from accidental exposure
15.2 59.2 Lowest reported infant survival from accidental exposure
10 50 Oxygen consumption 8% of normal
9 48.2 Lowest reported survivor from therapeutic exposure
Patients experiencing severe hypothermia (core temperature < 900 F or 32� C) may be disoriented & confused. As their temperatures continue to fall, they will proceed into stupor & complete coma. Shivering will usually stop, & physical activity will become uncoordinated. Muscles may be stiff & rigid. Continuous cardiac monitoring is indicated for anyone experiencing hypothermia. The ECG will frequently show pathognomonic (indicative of a disease) J waves, also called Oshorn waves, associated with the QRS complexes (Figure 1), but these are not useful diagnostically. Atrial fibrillation is the most common presenting dysrhythmia seen in hypothermia. As the body cools, however, the myocardium becomes progressively more irritable & may develop a variety of dysrhythmias. In severe hypothermia, bradycardia is inevitable.
Table 2. Hypothermia: Signs & Symptoms
Lethargy No shivering
Shivering Dysrhythmias, asystole
Lack of coordination Loss of voluntary muscle control
Pale, cold, dry skin Hypotension
Early rise in blood pressure, heart, & respiratory rates Undetectable pulse & respirations
Ventricular fibrillation becomes more probable as the body's core temperature falls below 86� F (30� C). The severely hypothermic patient requires assessment of pulse & respirations for at least 30 seconds every 1 to 2 minutes.
Treatment for Hypothermia
All victims of hypothermia should have the following care:
1. Remove wet garments.
2. Protect against further heat loss & wind chill. Use passive external warming methods such as application of blankets, insulating materials, & moisture barriers.
3. Maintain the patient in a horizontal position.
4. Avoid rough handling, which can trigger dysrhythmias.
5. Monitor the core temperature.
6. Monitor the cardiac rhythm.
Victims of mild hypothermia may also be rewarmed, using active external methods. This includes the use of warmed blankets and/or heat packs placed over areas of high heat transfer with the core: the base of the neck, the axilla, & the groin. Be sure to insulate between the heat packs & the skin to prevent burning. Intravenous fluid heaters (i.e. Hot T.V.) can be used to warm the IV fluid to 95° to 100° Fl 35° to 38° C. Warmed IV fluids are helpful in treating mild to modcrate hypothermia. Heat guns & lights may also be used, but this will most likely take place in the emergency department. Warm water immersion in water between 102° & 104° F (39° to 40° C) may be used but can induce rewarming shock (see below), so this method also has little application in an out-of-hospital setting.
Active rewarming of the severely hypothermic patient is best carried out in the hospital using a prearranged protocol. Most patients who die during rewarming die from ventricular fibrillation, the risk of which is related to both the depth & the duration of hypothermia. Rough handling of the hypothermic patient may also induce ventricular fibrillation. Active rewarming should not be attempted in the field unless travel to the emergency department will take more than 15 minutes.
If such is the case, active internal means may also be used, including the use of warmed (102° to 104° F138° to 40° C) humidified oxygen, & administration of warmed IV fluids (also warmed to 102° to 104° F138° to 40° C). This is crucial to prevent further heat loss, but actual heat transferred is minimal, so there is limited contribution to the re-warming effort.
While application of warmed blankets is a safe & effective means of rewarming the hypothermic patient, application of external heat, as with heat packs, is usually not recommended in the prehospital setting. For effective rewarming, more heat transference is generally required than is possible with out-of-hospital methods. Additionally, application of external heat may result in rewarming shock by causing reflex peripheral vasodilatation. This reflex vasodilation causes the return of cool blood & acids from the extremities to the core. This may cause a paradoxical "afterdrop" core temperature decrease & further worsen core hypothermia. This, in turn, may cause the blood pressure to fall, especially when there is also volume depletion.
If active rewarming is necessary in the prehospital setting, for example when transport is delayed, administration of warmed IV fluids during rewarming can prevent the onset of rewarming shock.
Volume depletion can occur as a result of cold diuresis. Core vasoconstriction causes increased blood volume & blood pressure, so the kidneys remove excess fluid to reduce the pressure, thus causing diuresis. A warmed IV volume expander (e.g., normal saline) should be used both to prevent rewarming shock & to replace fluid lost from cold diuresis.
The conscious patient who is able to manage his airway may be given warmed, sweetened fluids. Alcohol & caffeine should be avoided.
There are certain resuscitation considerations when handling cardiac arrest victims with core temperatures below 86° F (30° C).
Basic Cardiac Life Support
BLS providers should start cardiopulmonary resuscitation (CPR) immediately, although pulse & respirations may need to be checked for longer periods to detect minimal cardiopulmonary efforts. Use normal chest compression & ventilation rates & ventilate with warmed, humidified oxygen. If an AED is available & ventricular fibrillation is detected, three shocks may be given. Further shocks should be avoided until after rewarming to above 86° F. CPR, rewarming, & rapid transport should immediately follow the three defibrillation attempts.
Advanced Cardiac Life Support
Since there is no increased risk of inducing ventricular fibrillation from orotracheal or nasotracheal intubation, ALS providers may intubate the patient & ventilate with warmed, humidified oxygen. Drug metabolism is reduced however, so administered medications, such as epinephrine, lidocaine & procainamide may accumulate to toxic levels if used repeatedly in the severely hypothermic victim. In addition, administered drugs may remain in the peripheral circulation. When the patient is rewarmed & perfusion resumes, large, toxic boluses of these medications may be delivered to the central circulation & target tissues. Lidocaine & procainamide may also paradoxically lower the fibrillatory threshold in a hypothermic heart & increase resistance to defibrillation. Bretylium & magnesium sulfate however, may be effective even in hypothermic hearts.
The American Heart Association recommends that, if the patient fails to respond to initial defibrillation attempts or initial drug therapy, subsequent defibrillations or boluses of medication should be avoided until the core temperature is about 86° F (300 C). This is because it is generally impossible to electrically defibrillate a heart that is colder than 86° F. Active core rewarming techniques are the primary modality in hypothermia victims who are either in cardiac arrest or unconscious with a slow heart rate.
Techniques that may be used include the administration of heated, humidified oxygen & warmed intravenous fluids, preferably normal saline, infused centrally at rates of 150 to 200 nil, an hour to avoid overhydration. Peritoneal lavage with warmed potassium-free fluid administered 2 L at a time may be used, as may extracorporeal blood warming with partial cardiac bypass. Obviously some of these techniques may only be carried out in a hospital setting.
When transporting a hypothermic patient, remember that gentle transportation is necessary due to myocardial irritability & that the patient should be kept level or slightly inclined with head down. Contact the receiving hospital for general rewarming options. When determining your destination, consider the availability of cardiac bypass rewarming.
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Figure 3. Frostbite
Frostbite is environmentally induced freezing of body tissues (Figure 3). As the tissues freeze, ice crystals form within & water is drawn out of the cells into the extracellular space. These ice crystals expand, causing the destruction of cells.
During this process, intracellular electrolyte concentrations increase, further destroying cells. Damage to blood vessels from ice crystal formation causes loss of vascular integrity, resulting in tissue swelling & loss of distal nutritional flow.
Superficial & Deep Frostbite
Generally, there are two types of frostbite: superficial & deep. Superficial frostbite (frostnip) exhibits some freezing of epidermal tissue, resulting in initial redness, followed by blanching. There will also be diminished sensation. Deep frostbite affects the epidermal & subcutaneous layers. There is a white appearance & the area feels hard (frozen) to palpation. There is also loss of sensation in deep frostbite.
Frostbite mainly occurs in the extremities & in areas of the head & face exposed to the environment. Subfreezing temperatures are required for frostbite to occur, although they are not necessary to produce hypothermia. Many patients who have frostbite will also have hypothermia.
There can be tremendous variation in how an individual can present with frostbite. For example, some patients feel little pain at onset. Others will report severe pain. A certain degree of compliance may be felt beneath the frozen layer in superficial frostbite, but in deep frostbite, the frozen part will be hard & noncompliant.
In treating frostbite, take the following recommended steps:
· Do not thaw the affected area if there is any possibility of refreezing.
· Do not massage the frozen area or rub with snow. Rubbing the affected area may cause ice crystals within the tissues to damage the already injured tissues more seriously.
· Administer analgesia prior to thawing.
· Transport to the hospital for rewarming by immersion. If transport will be delayed, thaw the frozen part by immersion in a 102-104° F (39°-40° C) water bath. Water temperature will fall rapidly, requiring additions of warm water throughout the process.
· Cover the thawed part with loosely applied dry, sterile dressings.
· Elevate & immobilize the thawed part.
· Do not puncture or drain blisters.
· Do not rewarm frozen feet if they are required for walking out of a hazardous situation.
Trench foot (immersion foot) is similar to frostbite, but it occurs at temperatures above freezing. It is rarely seen in the civilian population. It received its name in World War I, when troops confined to trenches with standing cold water developed progressive symptoms over days. Symptoms are similar to frostbite, but there may be pain. Blisters may form upon spontaneous rewarming.
Treatment of trench foot requires early recognition of developing symptoms & immediate steps to warm, dry, aerate, & elevate the feet. Measures to prevent trench foot are most effective, such as avoiding prolonged exposure to standing water, changing wet socks frequently, & never sleeping in wet boots or socks.