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Introduction

First published in 1981by the INTERNATIONAL MARITIME ORGANIZATION

4 Albert Embankment, London SE1 7SR [ilhe purpose of this guide is to examine thehazards of cold exposure that mayendanger your life, and to provide you

with advice on how to prevent or minimizethose dangers. A thorough understanding ofthe information contained in this booklet maysome day save your life.

The sinking of the Titanic in 1912 provideda dramatic example of the effects of coldwater immersion. Partially due to a lack ofpreparedness with protective clothing, ofadequate flotation equipment, and of know-ledge of survival procedures, none of the 1,489persons immersed in the OaC water was alivewhen rescue vessels arrived one hour and 50minutes after the sinking. Countless livescould have been saved had the survivorsknown more of how to cope with cold water;almost all of the people in the lifeboats werealive.

During the Second World War the RoyalNavy of the United Kingdom alone lost about45,000 men at sea, of who m it is estimated30,000 died from drowning and hypothermia.Many of those who drowned did so becauseof incapacitation due to cold. Even today thepattern is similar.

lt is important to realize that you are nothelpless to effect your own survival in coldwater. Body heat loss is a gradual process, andresearch shows that in calm water at 5°C a

normally dressed person has only a 50%chance of surviving one hour. Simple self-helptechniques can extend this time, particularly ifthe person is wearing a lifejacket. You canmake the difference; this pamphlet is intendedto show you how.

Second edition, 1992

Printed by the International Maritime Organization, London

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ISBN 92-801-1273-2

IMO PUBLICATION

Sales number: IMO-946E

The illustrations on pages 13 and 15 arereproduced, by kind permission, from the

International Medical Guide for Ships, second edition(Geneva: World Health Organization, 1988),

figu res 2 and 3.

Copyright @ IMO 1992

All rights reserved.No part of this publication may, for sales purposes,

be reproduced, stored in a retrieval system ortransmitted in any form or by any means, e/ectronic,

e/ectrostatic, magnetic tape, mechanical, photocopyingor otherwise, without prior permission in writing from

the International Maritime Organization.

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Your body

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Ai n understanding of howyour body reacts

to cold air or water exposure, andknowing the steps you can take to help

your body delay the damaging effects of coldstress, will help you in your struggle to stayalive in the event of cold water exposure.

Imagine your bodY16cOnsist of an innercore and an outer layer. Within the core, yourbody produces a great deal of heat as a resultof normal body functions, such as physicalexercise and digesting your food.

Nature requires that your body core bekept to an ideal temperature of 37°C. A net-work of blood vessels running through thecore and the outer layer of your body picks upthe heat produced by the 'furnace' within thecore, and distributes the heat throughout thebody. Nature also gives your body a veryaccurate system to regulate automatically thecore temperature at 37°C. For example, if the

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temperature around you is high, as on a warmday or in a hot boiler room, the blood vesselsnear the skin of your body will enlarge,allowing more blood to flow to the outer layerand increase body heat loss. This will keepyou comfortable and keep the core tempera-ture from rising. If the surroundings are cool,your body will narrow the blood vessels in theouter layer and keep that valuable body heatfrom being lost too rapidly.

Vesselsenlarged

Vesselsnarrowed

This regulatory system strives to keep thecore temperature of the body constant despitevariations in ambient temperature around you.The body can only do this within certainlimits. There are levels of cold exposure whenthe body must have help in maintaining thecore temperature at nature's choice of 37°C.You must give it that help by taking correctactions and wearing protectiye clothing.

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. Conductionis the transfer of heat by direct

contact with cold water or other materials.

Heat passes from your body, which is at arelatively high temperature, to a substancewhich is lower in temperature. Certainsubstances are better conductors of heat

than others. Water conducts heat manytimes faster than air.

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Body heat loss and insulation

The body gives off its heat to the surroundingsin the following ways:

. Convectionis the transfer of heat by air or

water currents. Moving air is far cooler tothe body than stili air. Cooling by wind isknown as the 'wind-chill' effect. Similarly,disturbed or moving water around yourbody is more chilling than stili water at thesame temperature.

. Radiationis the transfer of heat by rays of

energy without direct contact with othersubstances, such as a radiator heating aroom.

. Evaporationis the vaporization, or 'drying

up', of liquid, such as sweat or moisturefrom wet clothing. When the body getstoo hot, sweating will occur and theevaporation of this sweat will help to caolthe skin. Although sweating can be veryuseful in providing you with a comfortablecooling effect on a hot day, evaporation ofmoisture from clothing can rob you ofvaluable body heat on a cold day.

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Radiiition

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In almost all parts of the world, man cannotsurvive without the aid of elothes. Clothes bythemselves do not warm the body; the body isactually warmed by its own heat production.The body heat warms the layer of air trappedbetween the skin and elothing. It is this layerof air that provides insulation. If the layer ofair is lost, then the insulation is diminished.This layer of trapped air between skin andelothing may be disturbed by movement ordisplaced by water. In either case, valuablewarm air is displaced and skin temperaturewill fall. Heat from the body core will then beused in an endeavour to maintain skin temp-erature. If heat 1055from the skin remainsunchecked, the body core temperature willfall.

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Hypothermia

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Tl he 1055of bodyheat isoneof thegreatest

hazards to the survival of a person at sea.The rate of body heat 1055depends on

water and air temperature, wind speed, seaconditions, the length of time spent in thewater, the protective elothing worn, the bodytype of the suryiyor, and the manner in whichthe suryiyor conducts himself. An abnormallylow body core temperature can be recognizedby a variety of symptoms. Very early duringexposure, the body tries to combat theexcessive heat 1055both by narrowing itssurface blood vessels (to reduce heat transfer

by blood to surface) and by shivering (toproduce more body heat). However, if theexposure is severe, the body is unable toconserve or produce enough heat. Body coretemperature begins to fall. When the bodycore temperature is below 35°C, the person issuffering from 'hypothermia'.

By then, discomfort, tiredness, poor co-ordination, numbness, impaired speech,disorientation, and mental confusion are wellestablished. As the internal temperature fallsbelow 31°C, unconsciousness may oecur,shivering is replaced by musele stiffness, andthe pupils of the eyes may be enlarged. Theheartbeat becomes irregular and weak and thepulse is barely detectable. Although death mayoccur at any stage of hypothermia, when aperson's temperature is below 30°C it is verydifficult to be sure whether he is alive or

dead. Death by hypothermia is then defined asa failure to reviye on rewarming.

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Marked shivering

Progressivemusclerigidity

Shivering ceases

Dilated pupilsthat stilireact

No pupil reflexes

Ship abandonment

Confusioni

Si hips may sink in less than 15 minutes.

This affords little time to formuiate a

plan of action, so careful planning isessential to be ready in an emergeney. Hereare some sound pointers for you to rememberwhen abandoning ship:

1 Put on as many layers of warm clothing aspossible, including fo ot protection, makingsure to cover head, neck, hands and feet.Fasten, close and/or button up clothing toprevent cold water flushing through theclothing.

If an im\TIersion suit is available, put it onover the warm clothing.

If the immersion suit does not have

inherent flotation, put on a lifejacket andbe sure to secure it correctly.

If time permits all persons should, beforeboarding the survival craft or in any caseimmediately after boarding, take somerecommended anti-seasickness medicine in

a dose recommended by the manufacturer.Seasickness will interfere with yoursurvival chances as vomiting removesprecious body fluid, and seasickness ingeneral makes you more prone to hypo-thermia and impairs your will to survive.

Avoid entering the water if possible, e.g.board davit-Iaunched survival craft on theembarkation deck or by the marine escapesystem. If davit-Iaunched survival craft, amarine escape system or other means ofdry-shod embarkation are not available,use over-side Iadders or, if necessary,lower yourself by means of a rope or firehose.

Disorientation

;,Amnesia

SleepinessHeartbeat slows

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Possibly abnormal heart rhythmsUnconsciousness

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Apparentdeath/Death

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Symptoms of hypothermia

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6 Unless it is unavoidable, do not jump intothe water from a height greater than 5 m.Try to minimize the shock of sudden coldimmersion. A sudden plunge into coldwater can cause rapid death, or an uncon-trollable rise in breathing rat e may resultin an intake of water into the lungs. Onoccasions, it may be necessary to jumpinto the water; if so, you should try tokeep your elbows to your side and coveryour nose and mouth with one hand whileholding the wrist or elbow firmly with theother hand. Avoid jumping onto the liferaftcanopy or jumping into the water astern ofa liferaft, in cas e the ship has someremaining headway.

Once in the water, whether accidentally orby ship abandonment, orient yourself andtry to locate the ship, lifeboats, liferafts,other survivors, or other floating objects. Ifyou were unable to prepare yourselfbefore entering the water, button upclothing now. In cold water, you mayexperience violent shivering and greatpain. These are natural body reflexes thatare not dangerous. You do, however, needto take action as quickly as possible beforeyou lose full use of your hands: button upclothing, turn on signal lights, locatewhistle, ete. A

While afloat in the water, do not attemptto swim unless it is to reach a nearby craft,a fellow suryiyor, or a floating object onwhich you can lean or climb. Unnecessaryswimming will 'pump' out any warm waterbetween your body and the layers ofclothing, thereby increasing the rate ofbody heat 1055. In addition, unnecessarymovements of your arms and legs sendwarm blood from the inner core to the

extremities (arms and legs) and thus to

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the outer parts of the body. This can resultin very rapid heat 1055. Stay calm and takeup a good position to prevent drowning.

The body position you assume in thewater is also very important in conservingheat. Try to float as stili as possible - withyour legs together, elbows close to yourside, and arms folded across the front ofyour lifejacket. This position minimizes theexposure of the body surface to the coldwater. Try to keep your head and neck outof the water.

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10 Try to board a lifeboat, raft, or otherfloating platform or object as soon aspossible in order to shorten the immersiontime. Remember: you lose body heat manytimes faster in water than in air. Since the

effectiveness of your insulation has beenseriously reduced by water soaking, youmust now try to shield yourself from windto avoid a wind-chill effect (convectivecooling). If you manage to climb aboard alifeboat, shielding can be accomplished

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with the aid of a canvas cover, a tarpaulin,or an unused garment. Huddling elose tothe other occupants of the lifeboat or raftwill also conserve body heat.

11 Keep a positive attitude of mind aboutyour survival and rescue. This will improveyour chances of extending your survivaltime until rescue comes. Your will to livedoes make a difference!

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Treatment of theimmersion survivor

inhe treatment for hypothermia will ofcourse depend on both the conditionof the suryiyor and the facilities available.

Generally speaking, survivors who are rationaland capable of recounting their experiences,although shivering dramatically, merely requireremoval of all wet elothes and replacementwith dry elothes or blankets. If possible, theyshould be taken from the water horizontally andcarried this way, or else be returned to thehorizontal (or, better stili, to the unconsciousposition illustrated on page 15) as quickly aspossible and kept this way. Hot sweet drinksshould be given but only if the victim is fullyconscious with gag and cough reflexes. Rest ina warm environment not exceeding 20°C(normal room temperature) is also recommended.Alcohol or smoking, as well as massaging orrubbing the cold skin, should be avoided.However, always bear in mind that evenconscious survivors can collapse and becomeunconscious shortly after rescue. They shouldtherefore be kept resting horizontally, withtheir legs slightly elevated (the 'shockposition'), and be watched for at least twohours.

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In more serious cases, where the suryiyoris not shivering and is semi-conscious,unconscious, or apparently dead, immediatefirst-aid measures will be necessary to preservelife while awaiting medical advice on moredetailed management procedures. This adviceshould be sought as soo n as possible and first-aid measures should not be delayed whileadvice is being sought. The recommendedfirst-aid measures for such an immersionsuryiyor are as follows:

1 On rescue, always check the survivor'sbreathing, carotid pulse for one minute (asillustrated), and pupillary reaction.

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WHO 861563

Carotid pulse

2 If the suryiyor is not breathing, make surethe airway is elear (remove dentures, if any)and start artificial respiration immediately(mouth-to-mouth or mouth-to-nose).

If the heart appears to have stoppedbeating then cardiac resuscitation may beapplied. However, you should be certainthat there is no pulse at all (remember thathypothermia slows and weakens the pulsegreatly) and, once started, it must be con-tinued properly until the patient is eitherfully rewarmed or delivered to a hospita!.

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3 If the suryiyor is breathing butunconscious, lay him in the unconsciousposition as illustrated on page 15. This isnecessary to ensure that the person'sbreathing is not obstructed by his tongueor by vomit.

Avoid all manhandling which is notnecessary to determine whether there areany serious injuries; do not even removewet elothes; do not massage.

Prevent further heat loss throughevaporation and from exposure to thewind. Wrap the patient in blankets and/ora casualty bag or large plastic bag andtransfer immediately to a (wind-)shelteredarea or below decks to a compartmentbetween 15°C and 20°C, keeping himhorizontal, slightly head down.

Advice on rewarming and decisionsregarding further treatment shouldnormally be given only by a doctor. If nomedical advice is immediately available,continue to apply the essential life-savingprocedures given in paragraphs 1 to 5above. In addition, if the rescued person iscold and appears dead, or if he deter-iorates and/or the pulse and breathing arelost, warming should be attemptedimmediately.

Medical authorities disagree on thebest method of rewarming, but either an'active' or 'passiye' method is normallyused, * Le.:

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* With respect to rewarming of hypothermia victims theInternational Medical Cuide for Ships recommends the'passiye' method on board the survival craft (p. 262) andthe 'active' method on board the rescue vessel (p. 268).However, where the person treating the victim has beentrained in onlyone of these methoôs of rewarming, in theabsence of medical advice to the contrary, onJy themethod of rewarming in which the person has beentrained should be used.

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.1 'Active' method of warming: this is donepreferably in a bath of warm water (38°Cto 400C - hand hot) or alternatively usingheated blankets or sheets (about 45°C,but not hotter);

.2. 'Passive' method of warming: cut theperson's clothing so that it can beremoved with the minimum of disturbance.Then wrap the person in blankets toreduce further heat loss. Do not attemptto warm the person by vigorous actions.Apply heating pads or hot water bottlesunder the blanket, to the person's head,neck, chest and groin - but never placethese warm objects against the bare skin,as cold skin is easily burned.

If active or passiye methods of warmingare not available the n apply body warmth bydirect body-to-body contact with the rescuedperson. In addition wrap ablanket around boththe rescued person and the person or personssupplying the warmth.

In all cases try to monitor the pulse andbreathing. .

Safe position for an unconscious patient: tu rn h im facedown, head to one side; no pillows should be used underthe head. Pull up the leg and the arm on the side towhich the head is facing, pull up the chin. Stretch otherarm out, as shown. elothes should be loosened at theneck and waist, and any articifial teeth removed.

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The above basic guidelines on first-aidtreatment for the unconscious person arei/lustrated diagramatica/ly below:

START(Recover in a horizonta/ position

whenever possib/e)

Cold injury

YES.

[AJnother condition which mav affectindividuals exposed to cold environmentsis acute cold injury. Such injuries usually

result from exposure to law temperatures,especially in damp conditions and when windspeeds are high. Cold injuries mav be of afreezIng or non-freezing variety.

..NO

1 Insulate to prevent further heat 1055throughevaporation and exposure to wind. Avoidunnecessary manhandling - leave wet elotheson and enelose in blankets and/or plastic bag.Move to sheltered location.

2 Lay d.own in the unconscious positionwhenever possible.

3 Oxygen should be given if available.

4 If water was inhaled, encourage deepbreathing and coughing.

5 Request medical assistance.

6 Watch person elosely until shivering starts.In the absence of medical advice rewarm theperson by either the 'active' or 'passiye' methoddescribed in paragraph 6.1 or 6.2 (page 15).

Freezing cold injury (frostbite)

Frostbite is the term given to the conditionwhen tIssue fluids freeze in 'Iocalized areas ofthe body; the hands, face, ears and feet areparticularly susceptible.

1 Clear airway, check carotid pulse and pupil-lary reaction.

2 Start artificial respiratioll' immediately(mouth-to-mouth, mouth-to-nose). If a pulsetannot be detected, commence cardiacresuscitation.

3 Insulate to prevent further heat 1055throughexposure to wind. Avoid unnecessary man-handling - leave wet elothes on and enelose inblankets and/or plastic bag. Monitor pulse,breathing and consciousness of victim andactively rewarm if the person appears dead orif the person's condition deteriorates.4 Seek medical advice. If medical advice is notavailable, continue resuscitation until thepatient is either fully rewarmed* or deliveredto a hospitai.

Ca use

Exposure, particularly of bare skin, to lawtemperature, especially when combined withmovements of moist/humid air. Look-outs in

liferafts or survivors in open boats areparticularly prone to this injury. Accordingly,consIderatIon should be gIven to the length ofwatch period.

DiagnosisEarly signs of frostbite are:

*Note: In the context of hypothermia a person cannot bepresumed dead until he is rewarmed and shows no bodilyfunctions.

extreme waxy pallor of the skIn;

initIal local tingling and stIffness - it isdifficult to wrinkle the face or wIggleaffected toes or fingers;

complete absence of sensatian in the areaaffected; and

4 local hardness due to freezing of the flesh.

N.B. Be watchful for the early signs offrostbIte in yourself and in others.

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Prevention

If bare skin has to be exposed to theelements, the periods of exposure should bekept to a minimum and freezing winds beparticularly avoided. Moderate exercise andmassage at an early stage will help to preventthe onset of cold injury. DO NOT smoke; smokingreduces the blood supply to the hands andfeet. Alcoholic drinks should not be consumed.

Prevention

Every effort should be made by survivors tokeep their feet warm and dry. Shoe-Iacesshould be loosened; the feet should be raised

and toe and ankle exercises encouragedseveral times a day. When possible, shoesshould be removed and feet kept warm byplacing them under the armpits, but outsidethe clothing, of an adjacent occupant.Alternatively, unwanted spare clothing may bewrapped round the feet to keep them warm.Smoking should be discouraged.

Treatment

On detection of the above signs, immediatesteps should be taken to rewarm the frozenpart before permanent damage occurs. Get outof the wind. Rewarm the frozen areas byapplying them to a warmer part of the body,e.g. hands under armpits, cupped hands overcheek, nose, ear, ete. The frozen areas canalso be rewarmed by placing them in waterwith a temperature of not mQre than 40°C.Once freezing has occurred, DO NOT rub ormassage affected areas.

Non-freezing cold injury (immersion foot)

Immersion foot is the term given to the conditionwhen the temperature of local tissues in thelimbs (usually the feet) remains subnormal butabove freezing for a prolonged period. It iscommonly encountered by shipwreck survivorswho have been adrift and cold for several days.Usually the feet have been wet and immobile,but this injury can also occur in dry conditions.Other contributory factors are tight footwearand sitting stili with the feet down as whensitting in a chair for prolonged periods.

Treatment

Af ter rescue, every effort should be made to

avoid rapid rewarming of the affected Iimbs.Care should be taken to avoid damaging theskin or breaking blisters. Elevate the lower legsto reduce swelling and cover lightly.Remember: nu mb limbs do not feel heat or

any other pain and are very easily burned. Donot massage affected Iimbs.

Summing up

[vv]e have briefly explained how your bodyresponds to cold, what you can do tohelp ward off the harmful effects of

cold and, finally, how to administer aid to animmersion suryiyor.

We will now sum up the story with anumber of important reminders. Follow them,for your life may depend on them.

1 Plan your emergency moves in advance!

Ask yourself what you would do if anemergency arose. Where is your nearestexit to the deck for escape? Where is the

DiagnosisFeet become white, numb, cold, andfrequently are slightly swollen. When returnedto the warmth, the feet become hot, red,swollen, and usually painfui.

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nearest available immersion suit, lifejacket,lifeboat, or raft? How would you quickly getto your foul weather gear, insulateddothing, insulated gloves?

2 Know how your survival equipment works.The time of the emergency is not the timeto learn.

3 Even in the tropics, before abandoningship, wear many layers of clothing to offsetthe effects of cold. Wear an immersion suitif available.

4 Put on a lifejacket as soon as possible in anemergency situation.

5 When abandoning ship, try to board thelifeboat or raft dry without entering thewater. Take anti-seasickness 'medicine as

soon as possible.

6 If immersion in water is necessary, try toenter the water gradually.

7 Swimming increases body heat loss. Swimonly to a safe refuge nearby.

8 To reduce your body heat loss, try to floatin the water with your legs together, elbowsto your side, and arms across your chest.

9 in a survival situation, you must forceyourself to have the will to survive. This willvery of ten make the difference between lifeand death.

In condusion, advance planning, preparationand thought on your part can be the mostsignificant factors in your struggle with coldwater immersion and in your survival.Familiarize yourself with the contents of thisbooklet.

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