23 Cold Water SurvivalCold Water Survival 2 Cold water hazards and their effects: knowledge that can improve survival chances An understanding of how your body reacts to cold air or water exposure, and knowing the steps you can take to help your body delay the damaging effects of cold stress, will help you stay alive. If you need to abandon your ship you should, if possible, avoid going into cold water at all. Cold water represents a much greater risk than cold air, partly because water takes heat away from the body much faster than air. Human beings cool four to ?ve times faster in water than in air of the same temperature – and the colder the water is the more likely it is that you will suffer the physical reactions and medical problems described below. Therefore, you should try to enter survival or rescue craft directly, without entering the water. The major threats of cold water immersion are: • drowning • hypothermia* (see appendix 2, page 20, Symptoms of hypothermia) • collapse just before, during, or after rescue. Four stages of immersion have been identi?ed. Each is associated with particular risks, and it helps to understand these and so be better able to deal with them. Initial responses to immersion in cold water may include: • inability to hold your breath • an involuntary gasp, followed by uncontrollable breathing • increased stress placed on your heart. These responses are caused by the sudden fall in skin temperature. It is important to remember that they will last only about three minutes and will then ease. Remember too that, at this stage: • the ?tter you are, the smaller the initial responses to cold water immersion and the smaller the chance of you experiencing heart problems • wearing an appropriate lifejacket, properly ?tted, will decrease the risk by helping to keep your airway clear of the water and reducing the need for you to exercise during this critical period • wearing appropriate protective clothing will also decrease the risk by slowing the rate of skin cooling and, thereby, the size of the initial responses • if you experience initial responses you should stay still for the ?rst few minutes of immersion, doing as little as possible until you have regained control of your breathing; a lifejacket or other source of buoyancy will help you do this • the period of possible self-rescue starts immediately after the initial responses, if experienced, and before hypothermia sets in. Short-term immersion effects follow the initial responses. During this phase, cooling of the muscles and nerves close to the surface of the skin – particularly in the limbs – can lead to inability to perform physical tasks. Swimming ability will be signi?cantly impaired. (Swimming accelerates the rate of cooling in any event.) It follows that: • essential survival action that requires grip strength and/ or manual dexterity – such as adjusting clothing or your * By medical convention clinical hypothermia is considered present when the “deep”, or “core”, body temperature falls below 35°C (95°F): that is, when about 2°C (3.5°F) has been lost. With continued cooling consciousness will be progressively impaired and then lost; eventually death will follow. However, in cold water death from hypothermia itself is relatively rare. More of a threat is the loss of heat from the muscles: incapacitation may then lead to the casualty being unable to keep their airway – the mouth and/or nose – clear of the water, so that they drown. Hence the importance of being well clothed and wearing a correctly ?tted and adjusted lifejacket. 89 Cold Water SurvivalCold Water Survival need to take action as quickly as possible before you lose full use of your hands. • Do not attempt to swim unless it is to reach a fellow survivor or a nearby shore, craft, or other ?oating object onto which you can hold or climb. Staying calm and still conserves heat. • If swimming, swim on your back, using only your legs, if possible. The arms are critical to heat loss. Not using your arms to swim means that you can keep them folded over your torso to assist in insulation. • Swim downwind of a ?oating object, if you are trying to reach it, rather than straight towards it. The wind will bring it in your direction. Once upwind of a liferaft, for example, you are unlikely to be able to reach it. Keep checking the object’s location and your progress towards it. If you decide that you cannot reach it, stop swimming, stay calm and stay still. • The body position you assume in the water is very important in conserving heat. Try to ?oat as still as possible, with your legs together, elbows close to your side, and arms folded across your chest. This position, which may only be fully achievable if you are wearing a lifejacket or dry suit, minimizes the exposure of the body surface to the cold water. • If the lifejacket is ?tted with a spray hood, put it on. The hood protects the airways against spray while drifting in the water. • The ?oating body tends to turn towards oncoming waves, with the legs acting like a sea anchor. If you have to, paddle gently to maintain a back-to-wave position. Although this may increase heat loss, you need to protect your airway from wave splash. • Link up with other survivors if you can. It helps location and rescue. • Keep a positive attitude of mind about your survival and rescue. This will extend your survival time. Your will to live does make a difference. 6 The rescue phase: guidance for those engaged in search and rescue Search may have to come before rescue. Remember to: • Search for long enough. Survival is possible, even after many hours in cold water. • Ask the Rescue Co-ordination Centre for advice, including on how long to keep searching. • Plan and prepare recovery methods for a variety of possible scenarios while searching. See IMO’s guidance on recovery, A Pocket Guide to Recovery Techniques. 1415 Cold Water SurvivalCold Water Survival • Oxygen should be given, if available. • If water was inhaled, encourage deep breathing and coughing. • Monitor and record breathing and heart rate (neck/carotid pulse) at ?ve minute intervals for the ?rst 15 minutes and then, if no change, at 15-minute intervals. (An increasing breathing and/or heart rate may indicate the onset of drowning complications. Remember that in a severely hypothermic person cardiac arrest can occur at any time.) • Seek medical advice. • When the survivor is alert and warm it is no longer necessary to maintain a semi-horizontal or horizontal position. • Give warm sweet drinks but no alcohol. If the survivor’s condition deteriorates, refer to the treatment procedure above for the unconscious patient. 8 Treatment of people recovered from survival craft Occupants who were exposed and dry for short durations (two to three days), and are fully alert, may require treatment for mild hypothermia, as described above for conscious immersion survivors. Occupants who are wet and cold and less alert will need to be recovered in a semi-horizontal position and should be treated in the same way as immersion casualties at the same level of alertness. Warm sweet drinks should be provided. Obtain medical advice. Free advice may be obtained from a Telemedical Assistance Service (TMAS), which can be contacted via a Rescue Co-ordination Centre. 9 The apparently dead What to do with people recovered apparently dead, showing no signs of life and extremely cold to the touch, is a very dif?cult question. In all probability they will indeed be dead, especially if there are witness reports from other survivors that they have been in that state for many hours. If, however, there are no such witness reports, the assumption must be that they may be alive but suffering from extreme hypothermia, that is, the heart may still be working, but at a very reduced level of activity, such that the pulse cannot be felt and the eye pupils are widely dilated. Always obtain medical advice as soon as possible. Free advice may be obtained from a Telemedical Assistance Service (TMAS), which can be contacted via a Rescue Co-ordination Centre. The apparently dead should be: • Recovered horizontally, if possible, and handled as if seriously ill. • The body should be gently placed in the recovery position in a warm sheltered compartment and well insulated. • If still alive, the body can rewarm very slowly at an optimal rate to allow it to compensate, by itself, for the major internal ?uid changes that occurred during the slow protracted cooling it endured. • Monitor and record pupil size and rectal temperature at hourly intervals for 12 hours. If there is no change and there are still no other signs of life, then it can be assumed that the casualty is dead. • If, however, pupil size decreases then, possibly, the casualty is alive. Commence monitoring and recording at 15-minute intervals, including checking for pulse and breathing.