Mountain and Cold Medical Considerations

8/14/2019 Mountain and Cold Medical Considerations

1/18

ColdWeatherMedicalConsiderations

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Contents:

IntroductionTheMountainEnvironment

Section1Hypothermia

Section2

Frostbite

Section3AcuteMountainSickness

Section4HighAltitudeCerebralEdema

Section5HighAltitudePulmonaryEdema

Section6SolarKeratitis(SnowBlindness)

Section7ConsiderationsforFirstAidSupplies

Bibliography


2/18

IntroductionTheMountainEnvironment

At10,000feetelevation(abovesealevel),thestandardairpressureis10.1psi. Thisis40%lessthanthe

airpressure atsea levelof14.7psi. Becauseof this, theamountofoxygenavailable toyourbody is

much less. At sea level, a normal amount of oxygen in oxygenated (arterial) blood is 97% of the

maximumcarrying

capacity,

at

10,000

feet

it

is

only

90%.

You

have

less

oxygen

to

work

with,

so

it

is

importanttouseitwell,throughcardiovascularconditioning. Bytheway,apackadaycigarettesmoker

is already cruising at 10,000 feet, when they are at sea level, based on their bloods oxygen carrying

capacitysosmokingisnothealthyforyouinthemountains,either.

Because of less air above you and the highly reflective snow around you, the effects of sunlight are

muchhigherwhichcan leadtosunburn. Thereflectionsfromthesnowonthegroundoften leadto

sunburnonnormallyprotectedareas(thelowerportionofthenoseandtheentranceofthenostrilsare

oftensunburnedinthesesituations). Sunburncanoccurevenindarkskinnedpeople,andcanbecome

severeenoughto leadtoblistering (seconddegreeburns) inboth lightanddarkskinnedpeople. Lips

can become sun and windburned, and this injury can lead to reduced desire to eat or drink

compounding

other

problems.

Mountaintemperaturesataltitudearealso lowerespecially inthewinter. Lowtemperaturesaffect

the body in different ways. It can both hurt you (via cold injuries like frostbite or hypothermia) and

make life difficult for your body. Since cold air is usually dry air, you will lose more bodily fluids

breathing than at normal elevations and humidity levels but because of the low temperatures,you

maynotfeelthirsty,andyoucanendupdehydrated. Waterisheavy,andcarryingenoughofittodrink

canbedifficult. Meltingsnow forwatertodrinkorcookwith istimeconsuming,andyoumustcarry

fuelabovetreelinetouseformelting. Thiscanaddtothedehydration. Becausethevariousmetabolic

processesinthebody(onthecellularlevel)arequitesensitivetothetemperatureandpHlevels,these

changescanaffecttheabilityofthebodytodigestfood,whichcanresultinloweredenergyavailability

justwhenyouneedextraenergythemost. Overall,themountainenvironmentischallenging.

Adaptation

Thehumanbodyhasaremarkableabilitytoadapttovariousenvironmentalconditionswhich iswhy

peopleliveinthehigharcticareaswherewintertemperaturescanbebelow 40oF,andinSaharanAfrica

where the temperatures can reach over 120oF, or from high humidity locations (jungles) to very low

(deserts), or high elevations (mountains) or low. Some adaptations happen quite rapidly, some take

longer. Someofthenormaladaptationsthathappeninclude:

Hyperventilation(deeper,fasterbreathingbecausethereislessoxygenavailableperbreathso

youneedmorebreath.

Shortnessofbreathonexertionwhichcan includejuststandingorsittingaround,sinceyour

body is working harder at altitudejust keeping you alive. Breath patterns during sleep can be quite

different,includingCheyneStokesrespiration(breathing)whichiscyclesofincreasinglydeepbreaths

followed by a short period of no breathing at all (called apnea)this is very noticeable in your tent

partnersandtheperiodsofapneacanbeenoughtowakeyouupfromsleep. Whiledistressing,thisis

normal, and aside frompreventinga good nights sleep isnotespeciallydangerous in theabsenceof

other medical problems. This is not AMS acute mountain sickness. CheyneStokes respirations

happenbecausedeeperbreathschangestheacidityofyourblood(makes itmorealkalinesinceyoure


3/18

blowing off carbon dioxide in the form of carbonic acid) and the part of your brain that controls

breathingsayswaitasecond,letslettheacidbuildupagain.

Awakeningfrequentlyatnightthisisannoying,butnotserious,andiscausedbydisruptionsin

breathing,CheyneStokesrespirations,beingcoldoruncomfortable,orneedingtourinate.

Finally,increased

urination,

especially

at

night.

Your

kidneys

are

responsible

for

keeping

your

bloodspHbalance inaverynarrowrange,andoneway itdoesthis isbyexcretingbicarbonate ions

which needs to be flushed from the body. This is only dangerous if you become dehydrated, so its

important to drink lots of water. Having a pee bottle at night makes this frequent urination less

onerous. Nothavingtourinate,especiallyatnight,maybeasignthatyouaredehydrated,whichcanbe

dangerous.

Likelihood

Somepeoplearemorelikelytohavevariousformsofaltitudeorcoldinjuriesthanothersare. Genetic

background,pastincidentsofcoldinjuries,chronicdiseases,andphysicalconditionareallvariablesthat

can affect individual performance. However, some people, even those in very good cardiovascular

conditioncan

have

difficulties

in

the

cold/high

altitude

environments,

and

people

who

have

done

well

previously can have difficulties apparently without an obvious reason. Only time will tell. One good

marker forexpectingdifficulties from cold injuries isapreviouscold injury: Ifyouhave had frostbite

beforeyouaremuchmore likelythanothers inthesameconditionstohave itagain. Likewise, ifyou

havehadaltituderelatedproblems,youaremorelikelytohaveitagain. Knowyourlimitations.

Risksofchronicconditionsinthemountainenvironment

MinimalriskSomedocumentedrisk considermedical

monitoring,availabilityofoxygen

Substantialrisk

ascentnotadvised

Childrenandelderly Carotidsurgeryorirradiation COPD,severe

Physically

fit

and

unfit

Sleep

disordered

breathing

and

apnea

Coronaryarterydisease,withpoorly

controlledangina

Obesity COPD,moderate CHF,uncompensated

Chronicobstructivepulmonarydisease(COPD),

mildCysticfibrosis

CongenitalheartdiseaseASD,PDA,

Downssyndrome

Asthma Hypertension,poorlycontrolled Pulmonaryhypertension

Hypertension,controlled Coronaryarterydisease,withstableangina Pulmonaryvascularabnormalities

Coronaryarterybypassgrafting,angioplasty,or

stenting(withoutangina)Arrhythmias,highgrade

Sicklecellanemia(withhistoryof

crises)

Anemia,stable Congestiveheartfailure(CHF),compensated Pr egnancy,highrisk

Migraine Sicklecelltrait

Seizuredisorder,onmedication Cerebrovasculardisorders

Diabetes

mellitus

Seizure

disorder,

not

on

medicationLASIK,PRK Radialkeratotomy

Oralcontraceptives Diabeticretinopathy

Pregnancy,lowrisk

Psychiatricdisorders

Neoplasticdiseases

Inflammatoryconditions

Fromtable385,TravelMedicine1stEd.


4/18

Prevention

Mostmedicalproblemsduetothemountainenvironmentarepreventable.

Be

aware

of

your

own

condition,

and

the

condition

of

your

partners.

The

onset

of

most

problems

is

insidiousandthevictimmaynotbeawareofthembothvisibleproblems likefrostbiteandproblems

thatmayresultinbehavioralchanges,forinstanceduetolessoxygenintheair.

Havingthecorrectequipment(clothing,shelter,water,sunglasses,etc)iscriticaltopreventinginjuries

butyouhavetocarryallthatgear! Takewhatyouneed,buttrynottooverdoit.

Structure

Definitionsarenormallyexplainedwhenatechnicalormedicalterm isfirstused. Generally,however,

thedistinctionbetweenasignandasymptom is important: (symptomsarewhatthepatientreports,

signs are what the physician can see, touch, or measure). In other words, you complain about

symptoms,thedoctorseessigns.

Eachsectionissetupwitha

Definitionof the condition; the keys todifferentiating conditionswithsimilar signs/symptoms

betweenseriousandnonseriousconditions

Identifyingthecondition(signsandsymptoms,and ifnecessaryhowtotellaseriouscondition

fromalessseriousonewithsimilarsignsandsymptoms

Treatmentbothimmediateandintermediate

Prognosis,orhowthevictimcanbeexpectedtofarewiththecondition,andmostimportantly

Prevention. Preventioniseasyforalloftheseconditions,andismuchpreferredovertreatment.


5/18

Section1:Hypothermia

Definition

Hypothermia is the loweringof thebodiescore temperature, which isnormallyaround37oC (98.6oF),

below the normal range (that is, to a temperature below 35oC or 95oF). While hypothermia is often

deliberatelyinduced

(for

certain

kinds

of

surgery,

for

example)

we

are

only

concerned

with

accidental

hypothermia.

Accidental hypothermia can occur slowly and insidiously because of inadequate clothing in cold

temperatures,orsuddenlyandcatastrophically,fromfallingthroughafrozen lakesurface. Eitherway,

loweringthebodiestemperatureisdangerous. Thevariouschemicalprocessesthatoccurinyourbody

areverysensitivetoslightchangesinconditions,includingtemperature,andloweringtheirtemperature

canstopthemfromhappening.

IdentificationSigns,symptoms

Theclassicsignofhypothermia isa2oC(ormore) lowerthannormalbodytemperature. So,thebest

wayto

identify

hypothermia

is

with

athermometer.

Special,

low

range

thermometers

are

available

for

hypothermiause,mostoraldigitalthermometerswillreadlowenoughaswell.

Hypothermiacanbe categorizedby theeffect that lower temperaturescause,anddifferentiated into

fourdistinctrangesthatcanbeestimatedbytheirsigns:

Stage CoreTemp Characteristics

Mild 99.6 Normalrectaltemperature

98.6 Normaloraltemperature

96.8 Increaseinmetabolicrates,preshiveringmuscletone

95.0 Maximumshivering(togenerateheatfrommusclemovement)

93.2 Developmentofpoorjudgmentandamnesia

91.4 Developmentofataxia(staggeringgate)andapathy,fasterbreathing(tachypnea)

Moderate 89.6 Stupor

87.8

Shiveringstops

(DANGER)

86.0 Atrialfibrillationandotherheartarrhythmiasbegin

85.2 Progressive decrease in level of consciousness, pulse, and respiration; pupils dilated; paradoxical

undressing(thevictimiscoldbutremovesclothing)

Severe 82.4 Ventricularfibrillationbegins,hypoventilation(breathingnearlystops)

80.6 Lossofreflexesandvoluntarymotion

78.8 Majorbloodacidbasedisturbances,nopainresponseorreflexes

Profound 68.0 Pulse20%ofnormal

64.4 Asystole(heartstops,flatlines)

59.2 Lowestinfantaccidentalhypothermiarecovery

58.6 Lowestadultaccidentalhypothermiarecovery

Treatmentinitial,intermediate

Foramild

to

moderately

hypothermic

person,

the

most

important

step

is

to

first

stop

their

heat

loss.

Get them into warmer surroundings, dry or warm clothes, and/or get them out of the wind. Even a

slightwindbreakcreatedbydiggingasmalldepressioninsnowisbetterthancontinuingtoexposethe

patienttotheeffectsofwindchill,atent,oramoreformalstructureisbetter.

Formoderately(ormore)hypothermicpatients,expecttheirheartstobeirritabledonthandlethem

roughlywhileattemptingtowarmthembecausetheroughhandlingmaycauseaheartarrhythmia.


6/18

Forpatients foundwhoappeartohaveseveretoprofoundhypothermia,considerpostponingCPR. A

rigid chest wall will prevent chest compressions, and blood pH changes can themselves cause heart

arrhythmias,especiallywhencoldperipheralbloodmovestothecorebymechanicalcompressions.

Moderately or more hypothermic patients should be transported to medical care for evaluation.

Warmingcanoccurwithgentlehotwaterbottlesinthegroinandaxilla, ifthevictim isabletograspa

containeranddrinkfromitonhisown,warmfluids(nonalcoholic)canbetakeninsmallsipsbutmake

certainthefluidsarenttoowarm,sincereflexesandtemperaturesensationmaybemissing.

Ifavictim is foundcold,pulseless,andunresponsive, treat themasaprofoundlyhypothermicvictim:

Handlegently,packagefortransport(seebelow),andgetthemtodefinitivemedicalcareasrapidlyas

possible. It is impossible to tell in the field if a patient is suffering from a heart attack, or profound

hypothermia,bothcaneasilymimicconditionsofdeath. ThereisasayingThepatientisntdead,until

theyrewarmanddead,becauseofthisgivethevictimthechance,ifpossible.

PreparingthehypothermicpatientforTransport

Prognosis

Theprognosis isdependentonthedegreeofhypothermiathatthevictimsustained. Itcanvary from

fullrecoverywithnosequelaetobeinginapersistentvegetativestatefromprolongedhypoxia.

Prevention

Staywarmanddry. Avoidoverheatingandconsequentialperspiration,whichwillresultinrapidcooling

onceyourexertionsstop. Wearingwickingundergarmentstomovemoistureawayfromyourskinwill

helpkeepyoudry,butyoumustcontrolyourperspirationandventilationtostaydry.

Vasculardilators(bloodpressuremedication)mayincreasetheriskofhypothermia. Discussusingthem

withyour

physician

prior

to

cold

exposure.

1. Thepatientmustbedry.Gentlyremoveorcutoffwetclothingandreplaceitwithdryclothingoradry insulationsystem.Keepthe

patienthorizontal,

and

do

not

allow

exertion

or

massage

of

the

extremities.

2. Stabilizeinjuries(i.e.,thespine;placefracturesinthecorrectanatomicposition).Openwoundsshouldbecoveredbeforepackaging.

3. Initiateintravenousinfusions(IVs)iffeasible;bagscanbeplacedunderthepatient'sbuttocksorinacompressorsystem.Administera

fluidchallenge.

4. Active rewarming should be limited to heated inhalation (if available) and truncal heat. Insulate hot water bottles in stockings or

mittensandthenplacetheminthepatient'saxillae(armpits)andgroin.

5. Thepatientshouldbewrapped.Beginbuildingthewrapbyplacingalargeplasticsheetontheavailablesurface(floor,ground),andon

itplaceaninsulatedsleepingpad.Alayerofblankets,asleepingbag,orbubblewrapinsulatingmaterialislaidoverthesleepingpad.The

patientisthenplacedontheinsulation.HeatingbottlesareputinplacealongwithIVs,andtheentirepackageiswrappedlayeroverlayer,

with the plastic as the final closure. The patient's face should be partially covered, but a tunnel should be created to allow access for

breathingandmonitoring.


7/18

Section2:Frostbite

Definition

While hypothermia is a reduction in the bodys core temperatures, frostbite, frosting, chilblains and

trenchfootarehypothermiarelatedinjuriestoperipheral(extremity)tissues.


Frostbiteinjuriesarecategorizedintodegreesofdamage,similarlytoburns.

First andseconddegreefrostbitesaresuperficial injuriesthatpresentwithedema(swelling),burning,

erythema(redness),andinseconddegree,blistering.

Thirddegreefrostbiteisadeeperinjuryinvolvingthefullthicknessskinandthesubdermaltissue. The

tissuesappearancewillbeonacontinuumfromtherednessoffirstdegreefrostbitetothepale,hard

tissue of fourth degree. Like burns, various areas of the affected tissue will have different levels of

frostbite.

Fourthdegree injury includes subcutaneous tissue, muscle, tendon, and bone. Patients present with

cyanoticandinsensatetissuethatmayhavehemorrhagicblistersandskinnecrosis. Subsequently,this

tissueappearsmummified.

FrostbiteInfeetandtoes

Figa Figb Figc

Fig a and b Before thawing, the clinical appearance of the frozen part is cold, white, or bloodless. The outer shell of skin is rigid,and the depth of freezing is difficult to determine. (c) After rapid thawing, the part is flushed red or pink, or has a violaceous hue.Blebs appear 1 to 24 hours after the thaw and rupture spontaneously in 4 to 10 days. The cast-like eschar forms after the blebs

rupture, and the eschar sheds after 21 to 30 days. PhotosfromMedicalAspectsofHarshEnvironments,vol1.

FrostbiteOuterEar


8/18

Figure a Figure b Figure c

Warmingtechniquesandtissueloss.(a)Frostbiteofanearwithouttissuelossafterrapidrewarming.Frostbiteofearin(b)ayoung

manand(c)anelderlypatient;eachhadtissuelossafterspontaneousthawing. PhotosfromMedicalAspectsofHarshEnvironments,vol1.FrostbiteInHandsandFingers

Figurea Figureb Figurec Figured

Figuree Figuref

Rapidrewarminginawaterbathat42C(108F). (a)Firstday. ThepatientsustainedfreezingofhandsandfeetontheArcticSlope

whenmaroonedintheopenasaresultofavehicleaccident. Windswere80knots,ambienttemperaturebetween20Cand26C.

Thepatientlosthisoverbootsandglovesintheaccident.Hisentireexposuretime,hestates,was15to20minutes,followedby45

minutesinthewreckedvehicleawaitingrescue. Onrescue,hewaswarmedinwaterat42C(160F);thewarmingandcarewere

directedbyradiofromAnchorage,Alaska. ThepatientwasthentransferredfromtheArcticOceanshoretoAnchoragebyairtravel

at24hours. Onarrival,thehandsdemonstratedlarge,clear,pinkblebsextendingtofingertips;theseareexcellentprognosticsigns,

especiallythat

the

blebs

are

distal

and

extend

to

the

nailbeds.

NOTE:

Only

after

rapid

rewarming

in

warm

water

is

there

return

of

sensation inthe fingertips;thisremainsuntilblebsappear inthedermisandepidermisandseparate those tissues from thedeep

structures. (b) Fourth day. Constant, twicedaily whirlpool is prescribed with digital exercises, using surgical soaps such as

pHisoHex,*Hibiclens,orBetadine.(c)Twentyfirstday.Bythethirdweek,epidermalescharhasformed,preventingjointmotion.

(d) Fourth week. Periodically, when the tissue permits, the eschar is incised to allow joint motion. Escharotomy usually is

performedfromthe14thtothe31stday.(e)Fifthweek.Digitalexercisesaredoneatfrequentintervalsatleastfourtimesdaily,as

withwhirlpoolandbiofeedback training.By this time, lossofvolar fatpadand lossofnailshaveoccurred andhypesthesia is

resolving.(f)Seventhweek.Theanatomicalresultisgood,butvolarfatpadlossandintrinsicmusclelossareobvious.Thepatient

has considerable atrophy of the first dorsal interosseus, and of the abductordigiti quinti. PhotosfromMedicalAspects ofHarshEnvironments,vol1.


9/18


Rapidlyrewarmfrostbiteoveraperiodof20minutesinwaterrangingfrom40to42C(104107oF). Be

carefulthewaterisnottoohotnormaltaphotwateristoohot,itcancauseseriousdamagethatthe

victimmaynotbeabletosenseduetothelossofsensationfromthefrostbite.

Donotmassageorrubthefrozenpartitmightincreasetissuedamage. Rewarmingwillbepainful;use

ananalgesicaneeded. Ibuprofen(Motrin)ispreferredinthisapplicationsinceitsprostaglandineand

thromboxaneinhibitingroleassists inpreventingfurthertissuedamagebypreventingvasoconstriction

andplateletaggregation.

Prognosis

Prognosis of frostbite injury depends on the degree and location of the injury, but can be severe,

especiallyifnottreatedcorrectly,oriftheaffectedpartisallowedtorefreeze. Ifthereisanydoubtthat

the affected part can be kept from refreezing, consider delaying the initial thawing until there is

assurancethatthepartwillremainwarm.

Administration (by a medical professional in the appropriate setting) of tissue plasminogen activator

(tPa) given intravenously within 24 hours of injury and within 6 hours of rewarming significantly

decreasedtheextentofamputationinseverefrostbite.

Prevention

Frostbite isusuallypreventablebyproperclothing includingfaceshieldsormasks. Observepartners

or use a mirror to check your own nose and ears for frostbite if necessary. In extreme conditions,

consider spare gloves, hats, scarves, etc, in case you lose yours or they become wet. In particular,

keepingglovesandsocksdrycanbeproblematic,havingsparestochangeintocanbeimportant.

Use

of

ergot

alkaloid

drugs

(sometimes

used

for

migraine

treatment)

can

increase

the

chances

of

developingfrostbitediscussusingorstoppingthedrugswithyourphysicianpriortotravellingtocold

locations.

Nonfreezingcoldinducedinjuries

Chilblains Chilblains (pernio) presents with painful and inflamed skin lesions caused by chronic,

intermittentexposuretodamp,nonfreezingambienttemperatures.

Frostnip isalesssevereformoffrostbitethatresolveswithrewarmingandinvolvesnotissueloss.

Trenchfoot Trenchfootresultsfromcoolingoftissueinawetenvironmentatabovefreezing

temperaturesoverseveralhourstodays. Longtermhyperhidrosis(increasedperspiration)andcold

insensitivityarecommonresults. Preventionisbykeepingfeetdrybychangingsocksasneeded.

Onceaffectedbychilblains,frostnip,orfrostbite,theinvolvedbodypartbecomesmoresusceptibleto

reinjury.


10/18

Section3:AcuteMountainSickness

Definition

AMS is a constellation of symptoms that represents your body not being acclimated to the current

altitude. Asyouascend(bywalking,driving,flying,oranyothermethod)yourbodyattemptstoadjust

tothe

hypoxia

(reduced

oxygen

available

at

that

altitude).

Atanygivenaltitude,there isasweetspotthatyourbodytriestoachievebetweenbreathing,blood

pressure,metabolism,etc. AMSoccurswhenyourbodyisnotinthatsweetspot.

TheactualcauseofAMSisnotunderstood,itisthoughtthatslightbrainswellingcausedbyachangein

bloodpHmaybeinvolved.


AsdefinedbytheLakeLouiseConsensusontheDefinitionsofAltitudeSickness,AMSisagroupingof

symptoms thatinthesettingofrecentaltitudegain,anyoneormoreofthefollowingsymptomsconstitutes

AMS:

In

the

setting

of

arecent

gain

in

altitude,

the

presence

of

headache

and

at

least

one

of

thefollowingsymptoms

Gastrointestinaldistress(anorexia(lossofappetite),nauseaorvomiting);

Fatigueorweakness;

Dizzinessorlightheadedness,ataxia(unsteadygait);

Difficultysleeping; constitutesAMS.

Clearly,thesecommonsymptomsmayresultfromanynumberofunrelatedconditions. More

specifically,AMScanbeconsideredasevereheadache(oftenintheareaabovetheeyes)thatisnot

causedbydehydration(seebelow),andsevereindicationsoftheseothercriteria.

DifferentiatingAMSandsevereheadache.

Severeheadachescanbecommon inthemountainenvironment,duetocold,dehydration,andstress

but this is not the same as AMS. While it is impossible to totally differentiate between these two

causes, if a person complains of a headache first have them drink a liter of fluid, and take a mild

analgesic (ibuprofen (Motrin),acetaminophen (Tylenol),aspirin)andhave them restabit: Iftheir

headache resolves completely in a short time (3060 minutes) it is probably not AMS related. AMS

symptomsdontresolvewiththesetreatments,noraretheymadeworsebythem.


Ifsymptoms

are

caused

by

AMS,

descending

is

the

best

treatment.

A

descent

of

only

1000

2000

feet

may be sufficient to resolve the symptoms. Because of the unsteady gait, the victim must have

assistanceduringthedescentusuallyatleasttwopersonstohelpsteadythem.

A prescription drug, acetazolamide (Diamox) can be given orally (250mg, bid) if available, and the

individualisnotallergictosulfatypedrugs. AcetazolamidedoesnotpreventallsymptomsofAMS,does

notmaskthesymptomsofAMS,andisnotareplacementforslow,steadyacclimatization.

SupplementaloxygentherapyisusuallynotindicatedforAMS,descentisafarbettertreatment.


11/18

Hyperbaricchambertherapy(Gamowbagorsimilar)isnotindicatedforAMStherapyatintermediate

altitudes.

Recently, some interest in gingko biloba as a cure or preventative for AMS has been discussed.

Extensivedoubleblindinvestigationshaveshownthatgingkoisnobetterthanaplaceboinpreventing

AMS,soitsuseisnotrecommended.

Prognosis

TheprognosisfollowingAMSisgenerallygood. Withrapiddescent,thepatientusuallyrecoverswithout

anysequelae. Itgenerallywontkillyou (although theheadachecanbesoseverethatat firstyoure

worried it will kill you, then youre worried it wont), but it can develop into HACE high altitude

cerebraledema(seebelow),whichisquiteserious.

Prevention

Slow, steady acclimatization is the key to avoiding most altitude related conditions. The typical

individualstravelfromnearsealeveltotrailheadsatsomeconsiderableelevation,justtojumpofftoa

higherelevation

on

foot

is

asure

prescription

for

AMS

and

other

altitude

related

disorders.

Forlongerascentsagoodstrategytofollowforclimbingistoclimbhigheachday,butreturntoalower

altitudetosleepforthenight. ThisismoreapplicabletoexpeditionclimbssuchasintheHimalayas,but

ifpossible,itworksatloweraltitudes.


12/18

Section4:HighAltitudeCerebralEdema(HACE)

Definition

HACE can be considered a serious continuation of the constellation of symptoms of AMS. At the

"severely ill" end of this spectrum is High Altitude Cerebral Edema; this is when the brain swells and

ceasesto

function

properly.

Since

the

skull

is

rigid

in

adults

any

swelling

compresses

the

brain

tissue,

obstructingbloodflow,andinseriouscasescancausethebrainstemtoherniate(squeezethrough)the

openinginthebottomoftheskullthatthespinalcordpassesthrough,theforamenmagnum.

Persons with this illness are often confused, and may not recognize that they are ill. They are, and

propertreatmentiscritical.

HACE can progress rapidly, andcan be fatal in a matter of a few hours to one or two days. It can

rapidlybecomeamedicalemergency,requiringtreatmentorthevictimmaydie.


Canbe

considered

"end

stage"

or

severe

AMS.

In

the

setting

of

arecent

gain

in

altitude,

either:

Thepresenceofachangeinmentalstatusand/orataxiainapersonwithAMS

Or,thepresenceofbothmentalstatuschangesandataxiainapersonwithoutAMS

ThehallmarkofHACEisachangeinmentation,ortheabilitytothink. Theremaybeconfusion,changes

inbehavior,orlethargy. Thereisalsoacharacteristiclossofcoordinationcalledataxia. Thisstaggering

walk issimilarto thewayapersonwalkswhenvery intoxicatedonalcohol. This lossofcoordination

may be subtle, and must be specifically tested for. Have the sick person do a straightline walk (the

"tandemgaittest").

Drawastraight

line

on

the

ground,

and

have

them

walk

along

the

line,

placing

one

foot

immediately

in

front of the other, so that the heel of the forward foot is right in front of the toes behind. Try this

yourself. Youshouldbeabletodoitwithoutdifficulty. Iftheystruggletostayontheline(thehighwire

balancingact),cannotstayonit,falldown,orcannotevenstandupwithoutassistance,theyfailthetest

andshouldbepresumedtohaveHACE.


ImmediatedescenttolowerelevationsisthepreferredtreatmentforHACE. Thisiscriticallyimportant,

it must be done immediately, it cant wait until morning even though HACE symptoms become

apparent or worse at night. The moment HACE is recognized, begin evacuating the victim, with

assistance,(atleasttwopeopleassisting),toatleastthelowestelevationthevictimlastfeltwell.

Other treatments, including supplemental oxygen therapy, hyperbaric chambers (Gamow bags or

similar),etcarelesseffectiveintreatingHACE.

Pharmaceuticaltherapywithsystemiccorticosteroidsmaybeusedaswell. Dexamethasone(4mg,two

doses 6 hours apart) may be given orally or intramuscularly if the patient is vomiting. These

supplementaltherapiesshouldnotbeusedincaseswheredescentandevacuationarepossible.


13/18

Prognosis

TheprognosisfromHACE isgenerallygood,withfullrecoveryhowevertheataxicgatemaycontinue

for several days following descent to normal elevation. Once full recovery occurs, the victim may

attemptre

ascent

with

proper

acclimatization.


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Section5:HighAltitudePulmonaryEdema(HAPE)

Definition

Anotherformofseverealtitude illness isHighAltitudePulmonaryEdema(HAPE),orfluid inthe lungs.

ThoughitoftenoccurswithAMS,itisnotfelttoberelatedandtheclassicsignsofAMSmaybeabsent.

HAPEmay

also

be

mistaken

for

other

diseases

(see

below).


Inthesettingofarecentgaininaltitude,thepresenceofthefollowing:

Symptoms:atleasttwoofthefollowing: Dyspnea(difficultyinbreathing)atrest;

cough;

weaknessordecreasedexerciseperformance;

chesttightnessorcongestion;

Signs:atleasttwoofthefollowing: cracklesorwheezinginatleastonelungfield;

centralcyanosis(bluetingetoskinoncentralbodychest,lips,throat,etcabluetingeon

lips,fingers,etcmaybecoldrelated);

tachypnea(rapidbreathing,fasterthan30breathsperminute);

Tachycardia(rapidheartbeat,greaterthan100beatsperminuteinarestingindividual);

Othersignsandsymptomsinclude:

Extremefatigue

Breathlessness

at

rest

Fast,shallowbreathing

Cough,possiblyproductiveoffrothyorpinksputum

Gurglingorrattlingbreaths

Chesttightness,fullness,orcongestion

Blueorgraylipsorfingernails

Drowsiness

HAPEusuallyoccursonthesecondnightafteranascent,andismorefrequentinyoung,fitclimbersor

trekkers. Insomepersons,thehypoxiaofhighaltitudecausesconstrictionofsomeofthebloodvessels

inthelungs,shuntingallofthebloodthroughalimitednumberofvesselsthatarenotconstricted. This

dramaticallyelevatesthebloodpressureinthesevesselsandresultsinahighpressureleakoffluidfrom

the

blood

vessels

into

the

lungs.

Exertion

and

cold

exposure

can

also

raise

the

pulmonary

blood

pressureandmaycontributetoeithertheonsetorworseningofHAPE.

HAPEcanbeconfusedwithanumberofotherrespiratoryconditions:

High Altitude Cough and Bronchitis both are characterized by a persistent cough, with or without

sputum production. There is no shortness of breath at rest, and no severe fatigue. Normal oxygen

saturations(forthealtitude)areseenifapulseoximeterisavailable.


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PneumoniacanbedifficulttodistinguishfromHAPE. FeveriscommonwithHAPEanddoesnotprove

thepatienthaspneumonia. CoughingupgreenoryellowsputummayoccurwithHAPE,andbothcan

cause lowblood levelsofoxygen. Thediagnostic test(andtreatment) isdescentHAPEwill improve

rapidly. If thepatientdoesnot improvewithdescent,thenconsiderantibiotics. HAPE ismuchmore

commonataltitudethanpneumonia,andmoredangerous;manyclimbershavediedofHAPEwhenthey

weretreatedforpneumonia.

AsthmamightalsobeconfusedwithHAPE. Fortunately,asthmaticsseemtodobetterataltitudethan

atsea level. Ifyouthink itsasthma,tryasthmamedications,but ifthepersondoesnot improvefairly

quicklyassumeitisHAPEandtreatitaccordingly.


Minimizeexertionandkeepwarm. LikeHACE,rapiddescent isthebesttreatment. Othertreatments

include:

Oxygen,4to6L/minuntilimproving,then2to4L/min

Ifoxygenisnotavailable:

Nifedipine,10mgPOq4hbytitrationtoresponse,or10mgPOonce,followedby30mgextended

releaseq12to24h

Inhaledbetaagonist (albuterol,Ventolin)

Considersildenafil(Viagra)50mgevery8hrs

HyperbarictherapyviaGamowbagorsimilar

Prognosis

ItiscommonforpersonswithsevereHAPEtoalsodevelopHACE,presumablyduetotheextremelylow

levels of oxygen in their blood (equivalent to a continued rapid ascent). HAPE resolves rapidly with

descent,andoneortwodaysofrestatalowerelevationmaybeadequateforcompleterecovery. Once

thesymptomshavefullyresolved,cautiousreascentisacceptable.

Prevention

Whilecarefulascentwithacclimatizationispreferred,somepeoplearepredisposedtoaltitudeillnesses

evenwithgoodphysicalconditioningandcarefulacclimatization.


16/18

Section6: UV/SolarKeratitis(SnowBlindness)

Definition

Becauseof lessatmosphereaboveyou filtering light,and thehighly reflectivesnowfieldsaroundyou,

theeyecanreceive1015timesasmuchlight,especiallyultravioletlight,asishealthy. Thisextralight

canresultintemporarydamagetotheouterlayeroftheeye.


Intensepainandafeelingofgritorsandintheeyes,feltwhenblinking. Theeyesarepainfulandthe

victimmayhaveanearlyuncontrollableurgetorubthem.


Treatment consists of antibiotic ointment (if available, and only optic formulations), mild analgesics

(NSAIDSlike

ibuprofen)

and

perhaps

eye

patching.

If

the

victims

eyes

are

patched,

they

are

unable

to

assistintheirownevacuation;ifonlyoneeyeispatched,theywillstillrequireassistancebecauseofthe

lossofdepthofvision.

Prognosis

The prognosis forsolarkeratitis is good while the condition is painful andannoying it will normally

resolvewithinadayortwowithoutanyfollowonproblems.

Prevention

Wearing

high

quality

tinted

glasses

or

goggles

will

help

prevent

snow

blindness

and

having

a

spare

pair

incaseyouloseorbreakyourprimarypairisagoodidea.

Goodgogglesorglasseshavethefollowingcharacteristics:

99100%UVabsorption

PolycarbonateorCR39lens(lighter,morecomfortablethanglass)

510%visiblelighttransmittance

Largelensesthatfitclosetotheface

Wraparoundorsideshieldedtopreventincidentallightexposure

Theactualcolor ismoreamatterofpersonalpreferencesomepeoplepreferneutralgray lensesto

minimize color changes, others find that various shades of yellow or amber help with flat light

conditions.

Ifsunglassesarenotavailable,areplacementcanbemadefromfabric,woodorplastictiedacrossthe

face(asglassesare)withasmallhorizontalslitcutinitovertheeyeposition,toprovidevision. While

wearingahatisnecessary,abrimmedhatwillprovideminimalprotectionagainstsnowblindness

becauselightwillbereflectedupfromthesnowontheground.


17/18

Section7:ConsiderationsforFirstAidKits

Becauseofthecoldtemperatures,avoid(asmuchaspossible)any liquidsorgels includingointments.

Drugs that freeze may separate, and when they thaw not recombine correctly, rendering them

dangerousoruseless. Inparticular,proteincontainingdrugs (suchas insulin)mustnotbeallowedto

freeze, or NOT USED if frozen the proteins will precipitate from the solution and can cause a

thrombosis.

Solidpillsortabletscanbe frozen ifneeded. Capsules (whicharemade fromgelatin)willdeteriorate

rapidlywhenfrozenandshouldbeavoided.

Ifliquidsorgelsarenecessaryandunavoidable,packthemwithgoodinsulation. Asmallchemicalheat

packmayhelpkeepthemfromfreezing;orkeepthemclosetoyourbody.

Hyperbaricchamber

therapy

Forhighaltitude(>15,000feet)atransportable,fabric,hyperbaricchambersuchastheGamowBagis

commercially available, for use when evacuation to lower elevations are not possible because of

distanceorweatherconditions. Thevictimisplacedinthebag,whichisthenzippedclosed,andafoot

operatedairpumpincreasestheatmosphericpressureinsidethebagbyapoundortwo,whichcanbe

theequivalent (athighaltitude)ofa5,000footdescent. Withsufficientresourcesthepatientcanbe

evacuatedwhileinthechamber,usingabasketstretcherorsimilardevice.

Gamowbag(picturefromWikipedia)

Gamow and similar bags are heavy, and somewhat expensive. They can be rented for specific

expeditionsfromvarioussourcesifdesired.


18/18

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Documents

Mountain and Cold Medical Considerations