Oxford Handbook of Expedition and Wilderness Medicine (2 edn)
Annotate
Cite
Aquatic environments
Drowning is the third leading cause of accidental death worldwide (after road traffic injuries and falls) and results in about 450,000 deaths a year,1,2 >70% of which involve alcohol. Serious medical problems such as seizures, ischaemic heart disease, and strokes may cause a person to collapse into water and then drown as a secondary event. In 2013, the RNLI in Britain and Ireland rescued 8384 people at sea, with a further 21,938 aided by beach lifeguards—but sophisticated rescue services are not universally available.
Aquatic environments, whether oceans, rivers, or lakes, are very complex, being affected by the flows of water, their interaction with surrounding land, and the interplay with other physical forces such as the wind. Expeditions using rivers or lakes as routes of communication also have to contend with the nature of the surrounding terrain and the local weather conditions.
All expedition risk assessments should consider aquatic hazards.
Water’s edge
Most deaths from drowning occur close to shore. Effective risk assessment requires an understanding of the nature of the coastal terrain or river hydrology.
Gradient
Vertical or steep edges: increase risk of slip into water of unknown depth, the edges may be unstable (e.g. decaying canal banks), and make it difficult to rescue a casualty.
Steeply sloping beaches: create dumping waves, and are prone to fast run-offs that can knock people off their feet.
Shallow beaches: often have long tidal ranges with rapid flows that can strand people on sandbanks.
Rapids: form as gradients increase, encouraging white-water activities, but fast currents increase risk for anyone in the water.
Construction
Shale/coral: painful to walk on, sharp pieces can penetrate the skin and cause infections. Formal surgical exploration may be required to remove the infective focus.
Sand: difficult to see animals such as rays that may be trodden on. May produce inshore holes, sandbanks, and rip currents.
Rock type: softer limestone and sandstone riverbeds erode into ‘holes’ that can trap or damage feet and equipment.
Boat launching areas: should avoid coral, urchins, dangerous currents, and other water users.
Landscape
Sandbanks: may falsely reassure about water depth; an incoming tide may produce a deep inshore zone between bather and the shore.
Inshore holes: troughs that run parallel to the shore that can be several feet deep, up to 50 m wide, and several hundred metres long. Rip currents develop as waves break over a sandbar and then run out to sea via the inshore hole.
Piers, outcrops: can also create rip currents. May be surrounded by sharp barnacles, submerged objects and waste.
Waste: glass, oil, and other discarded objects.
Flora: falling coconuts can cause severe head injuries. The Manchineel tree (Hippomane mancinella), found in countries bordering the Caribbean, has caustic sap and highly toxic fruits and leaves; don’t shelter under these trees. In some countries they are marked by a red cross or band on their trunk, elsewhere you need to be wary.
On small rivers in wooded areas, fallen trees lying across the river are very hazardous to small craft which may become jammed underneath.
Coastal landscape may prevent landing by sea kayak and small boats, cliffs may generate strong downdrafts and erratic wave patterns.
Water
Offshore
Tides, currents, and weather can vary unpredictably; seek local knowledge, although this can be hard to obtain in remote locations.
Self-rescue is difficult offshore from exposed and inaccessible coastlines.
Incoming tides can isolate people on sandbanks, and at the midpoint of ‘flooding’ can raise the level of the sea very dramatically in a short period of time. Outgoing tides can pull people and boats offshore. Both flows can be exacerbated by strong winds or storms.
Inshore drift: a current lateral to shore. Can displace water users into more dangerous areas.
Rip current: a body of water moving in a direction other than the general flow. If it is trapped behind a sandbank as the tide retreats water will flow quickly through deep channels. The flow is strongest when the waves breaking over a sand bar are at their maximum; and minimal over the rip channel. Rip currents can vary from a couple of metres wide to over 50 m, and on rare occasions flow hundreds of metres offshore. The flow will vary with the tides. Identifying features include:
Discoloration of the water from disturbance of silt or sand.
Darker water surrounding the main current flow.
Floating debris or foam on the surface.
Surface changes such as rippled water while the surrounding area is calm.
Waves breaking on either side of the rip.
If caught in a rip current: float, attract attention, and wait. Some rip currents will re-circulate you to the shore, sandbank or out to sea. If you are a competent swimmer you can consider swimming out of the rip aiming parallel to the shore and towards the breaking waves.
Rivers
Risks vary markedly according to the gradient, depth, and flow rate of water. Drop a stick in the river—if it moves faster than walking pace, the energy of the system is enough to knock you off your feet.
Fast-flowing rivers are likely to have stony bottoms, with sudden variations in depth; slow-flowing rivers have muddy bottoms, often with weeds. The outer side of a river bend will have the faster flow.
Flash floods are a serious risk in mountain regions. In glacial areas the water level will rise rapidly with melt water towards the afternoon. Identify any upstream dams or hydroelectric stations that may suddenly release massive volumes of water.
Rapids may change from year to year, affected by alterations to the riverbed and the volume of water flowing. Define the extent and complexity of portage if craft need to be transported around waterfalls and rapids.
Rivers may run through gorges from which escape is difficult; in flat areas, marshes and mud may make access and egress difficult.
On managed rivers, the unbroken stoppers of artificial weirs are a hazard; river confluences produce eddy currents.
Narrow, muddy, or wet rock riverside paths increase risk that a slip will cause injury or fall into water, especially during portages.
Waves
Dumping waves occur if the bottom is steep. They peak rapidly and drop the entire force of the wave into the floor, commonly pulling people off their feet and increasing the chance of spinal injury.
Spilling waves have a gradual slope; white water ‘spills’ down the front of the wave. The point of breaking is dependent on the wind direction.
Surging waves never break, lose speed, or gain height. They ‘surge’ into the beach and retreat as quickly, possibly dragging people into deep water.
Tidal river bores are predictable phenomena that sweep up estuarine rivers. Surfing them is increasingly popular, but significant skill is required and the rivers can be unpredictable.
Standing waves, seen on rivers, maintain their position relative to the current. They can trap craft and people wearing buoyancy aids.
‘Stoppers’ are the big hazard on rivers. They re-circulate vertically upstream, creating a wave that can trap boats in a pounding maelstrom that has a high risk of retention and capsize.
Sea
Coastal navigation is affected by tides, currents, and visibility.
Compass and maps or charts vital in case any electronic methods fail; in any case, preserving your map reading skills is also important. Both maps + electronic methods should be carried by other paddlers as backup. GPS systems can use a lot of batteries, but can plot mileage, and are useful for positive fix and emergency positioning.
For longer sea trips, estimate 10–15 miles a day (includes bad weather holdups).
Rock hopping, i.e. dodging around rocky shores is good fun and raises skills, but runs the risk of damage to both gear and, if capsized, to body.
Coasteering—navigation along the inter-tidal shoreline using a combination of walking, rock climbing, and swimming is increasing in popularity. Safety demands appropriate equipment, knowledge of ledges above and below water and tidal flows especially when youngsters are participating.
Tsunami, jøkulhlaup, and flash floods
Although rare, these natural phenomena can be catastrophic, devastating everything in their path, and leaving infra-structure wrecked. Many coastal countries have tsunami warning systems; expeditions must be aware of local alarms, the escape routes to higher ground, and designated muster points. In mountainous areas the overflow or breaching of glacial outflow lakes occasionally leads to catastrophic flooding. Many landscapes in Iceland have been formed as a result of flooding secondary to volcanic activity under the ice-caps; jøkulhlaup.
If you have time: exit buildings and head to high ground on foot.
If the water level is already rising, or high ground is too far away, go to the top of a well-constructed building near an exit and wait for initial surge to pass.
If time allows put passport, communications (EPIRB, satellite phone) into a waterproof bag and fix firmly to yourself.
If buoyancy aids are available, put them on as soon as possible.
If on a boat, head offshore as the wave height will be less.
Post disaster: identify all party members and contact the local embassy or consulate to inform them of your predicament.
Secondary floods, landslides, and building collapse are common.
Water will be contaminated; purification of drinking water is essential.
You may feel morally obliged to assist with disaster relief. Balance your involvement with the risk to yourself and your group of exposure to pathogens, depletion of expedition equipment, and the inevitable difficulties in finding clean food and safe water.
Other issues
Depth: compared to shallow areas, deep water will usually appear darker and be associated with less surface disturbance.
Submerged objects: rocks, tree roots, sunken vehicles, and outlet pipes are difficult to recognize. In calm areas look for unexpected waves breaking over the obstruction. Obstructions can form ‘strainers’ in a river system, trapping swimmers against them.
Plants, reeds, seaweed: can easily entrap swimmers or waders; use small gentle strokes to escape. Dense vegetation may hide snakes, crocodiles, etc. Floating debris is common after storm weather.
Quality: rivers and coastlines may be polluted by industrial, agricultural, or bacteriological effluent. Determine local dumping areas and sewage outlets. Smell or coloured algae foam can be an indication of hazardous zones. Problems commonest soon after heavy rain that overwhelms sewage systems.
Weather
Wind affects wave strength and formation, cools the skin, masks sunburn, and increases the risk of hypothermia. Down drafts near cliffs can be fierce.
Rain reduces visibility, increases the risk of hypothermia, and steep catchment areas can result in rapid change in river level.
Ultraviolet light from the sun reflects off the surface of the water, increasing exposure to radiation. Tropical climates encourage scanty clothing. Splash water washes off protective sun block creams. Minimize hazards by appropriate behaviour, clothing, and UV protection. UV exposure is greater at altitude. Reflected glare may affect underside of chin, nose, eyebrows, and eyes (the use of good quality sunglasses will reduce risk of long-term damage; 
Solar skin damage, p. 266). On the plus side, UV light reduces the pathogen load of natural bodies of water; minimum load is in the 2–3 h post midday.
Weather reports are important; if there are no reports available you may have to rely on your own personal observations and barometric analysis. In the USA/Canada, weather reports are transmitted continuously; several organizations provide satellite text weather messaging services, and phone apps are available.
For kayakers and canoeists, cold and wet weather leads to shorter days paddling and consequent pressure on schedules.
Travel on water
Getting craft and stores safely to and from a river can be challenging. River bridges, harbours and quays provide good landing points and escape routes, but away from such fixed locations, carefully planning is required.
Itineraries must consider the unpredictable stresses of multi-day journeys, which considerably exceed those of shorter leisure trips.
Escape routes and rescue plans must be considered especially in areas where access to the water is difficult.
Maps may not accurately highlight the physical characteristics of shorelines and riverbanks.
Portage routes must be planned and appropriate loads taken.
Navigation
On the water, most navigating is done from the boat (‘read and run’) as stopping to inspect rapids (‘scouting’) is a lot slower.
Need to be able to recognize white-water dangers—mainly ‘stoppers’ and small whirlpools below big water rapids, but also sumps, undercuts, ledge drops, waterfalls, and the risks of broaching and pinning.
Need to understand river flows as expressed by European metric cubic metres per second (cumecs) or American cubic feet per second (cfs). 1 cumecs = 35.3 cfs.
Coastal navigation is affected by tides, currents, and visibility.
Navigation through swamps, reed beds, and tunda shield terrain where there are numerous lakes and low hills can be exceptionally challenging. GPS may provide a position, but maps may be hard to interpret.
Environmental impact of humans
Away from centres of population and tourist destinations, communities at the water’s edge are often small, remote and poor, possibly with only tenuous road access to the outside world.
Sewage and garbage are diffuse and everywhere, especially after heavy rains.
Fish traps are occasionally placed in small channels at water’s edge or shallow seas.
Rescue
However stressful the situation, never add to the death toll; maintain your own and others’ safety. Have a realistic view of your own abilities and, unless highly skilled, avoid direct contact with a panicking casualty. Local rescue services may be primitive or non-existent.
Preventing accidents
Risk management
All expeditions working on or near water must consider the possibility of immersion and plan rescue procedures.
Drowning often occurs very quickly and unexpectedly.
A personal flotation device dramatically improves the chance of surviving an immersion—but only if it is worn. You may not have enough time to put it on if you are not already wearing it.
Accidents often happen out of reach of other party members. Use a buddy system to keep in touch with other team members.
Many incidents could be avoided with good risk assessment.
Rivers
Shouted commands are unreliable above the roar of moving water; if possible, discuss among rescuers before starting the rescue, personal radios if available may assist.
At river rapids: identify hazards, agree run, and decide running order.
In difficult areas, ‘set safety’ by distributing team members with appropriate rescue equipment in advance of the boats in case rescue is required.
Remember ‘reach, throw, wade, tow’; recognizing the hazards with each technique. Learn and practise proper use of throwbags.
Wading risks foot entrapment, and is best done with a paddle for support; or better as a pair or threesome, linking arms and with safety set downstream.
Ropes and karabiners may assist during rescues, but add to the hazard if people are not properly trained in their use.
Around coasts
There are many options for communication around coasts. Mobile or satellite phones and VHF radios enable surface-to-shore communications. Equipment should ideally allow communication with both rescue centres and rescue craft on a variety of frequencies.
GPS-PLB (personal locator beacons) are cheaper and smaller than EPIRB and have good battery life. They have world cover—in the UK, if the device is registered, the signal goes through Falmouth to local coastguards; and keeps transmitting for 10 h. A SPOT satellite GPS messenger sends pre-programmed text messages and also has buttons for routine plots of progress.3
Other vessels may be involved in rescue, so read relevant textbooks on managing such a rescue and also understand actions to take during helicopter rescue (see Helicopter evacuation, p. 722).
Rescue techniques
See Table 22.1.
| Choice | Intervention | Suitability and risk |
|---|---|---|
1st | Signal and shout | Effective for disorientated, weak, or injured swimmer. Low risk to rescuer |
2nd | Reach | Casualties that are within physical reach, or in reach with pole/stick, etc. Potential to be pulled in |
3rd | Throw | Floatable aids or rope effective for weak/injured swimmers. Rope throwing requires practise |
4th | Boat or dingy | Limited by availability, operator skill, time to set up, and water conditions |
5th | Swim with an aid | Swimming with floatable aid, can allow a small distance to be kept from casualty or assist tow. |
6th | Swim and tow | High risk owing to physical contact with panicking casualty. Energy sapping procedure. Avoid obstructing victim’s airway with towing technique |
| Choice | Intervention | Suitability and risk |
|---|---|---|
1st | Signal and shout | Effective for disorientated, weak, or injured swimmer. Low risk to rescuer |
2nd | Reach | Casualties that are within physical reach, or in reach with pole/stick, etc. Potential to be pulled in |
3rd | Throw | Floatable aids or rope effective for weak/injured swimmers. Rope throwing requires practise |
4th | Boat or dingy | Limited by availability, operator skill, time to set up, and water conditions |
5th | Swim with an aid | Swimming with floatable aid, can allow a small distance to be kept from casualty or assist tow. |
6th | Swim and tow | High risk owing to physical contact with panicking casualty. Energy sapping procedure. Avoid obstructing victim’s airway with towing technique |
Unconscious casualty
Approach swiftly; turn the casualty into a supine position. Prompt expired air ventilation (EAV) increases survival if the casualty is not breathing properly. Balance difficulties of administering rescue breaths against the time taken to exit the water, and rescuer’s capability to perform the skill. If there is only a short distance to safety—exit and then resuscitate; if a longer swim is involved, and you have the skill and strength, attempt in-water EAV. Casualties often vomit—be prepared.
Post-immersion collapse syndrome
Prolonged immersion creates dehydration, with BP supported by hydrostatic pressure of water on limbs. Rescue in horizontal position if practical. Vertical extraction carries the risk of cardiovascular collapse and death.
Injuries
Certain aquatic accidents predispose to life-threatening injuries. These include fractures and head injuries from high-velocity impacts such as fast watercraft, cliff diving, or anybody in heavy surf. Surfers and those diving into shallow water are at high risk of cervical spine injuries, which are otherwise relatively uncommon.
Mass rescue
If more than one casualty is present, rescue must be prioritized. (See Table 22.2.)
1st | Non-swimmer | Head going under water and unable to maintain a direction |
2nd | Weak swimmer | Able to hold position and direction of sight but not move |
3rd | Injured swimmer | Holds position, swims slowly, communicates injury |
4th | Unconscious | Usually face down. If the casualty is seen to go unconscious they are first priority to minimize period of hypoxaemia. But if period of hypoxia is unknown, victim may be dead and extraction of body from water will prevent rescue of other casualties |
1st | Non-swimmer | Head going under water and unable to maintain a direction |
2nd | Weak swimmer | Able to hold position and direction of sight but not move |
3rd | Injured swimmer | Holds position, swims slowly, communicates injury |
4th | Unconscious | Usually face down. If the casualty is seen to go unconscious they are first priority to minimize period of hypoxaemia. But if period of hypoxia is unknown, victim may be dead and extraction of body from water will prevent rescue of other casualties |
Humans in aquatic environments
Non-swimmers are obviously at greater hazard and require close supervision when near water.
Buoyancy aids (also called PFDs—personal flotation devices) should always be worn when close to or on the water. Attach a whistle for attracting attention. Buoyancy aids vary in cut, distribution of buoyancy, availability of pockets, and rescue fittings. Besides being flotation devices they:
Provide insulation in cool conditions.
Pad the body if in a collision.
Can be used as splints for fractured limbs.
Act as insulation from the ground if resting or sleeping.
Clothing: appropriate waterproofs, wet or dry suits, and helmets and may be required.
Body temperature: humans are aware of peripheral rather than core temperature. Wet suits, which maintain peripheral temperatures, may disguise drops in core temperature. Regular wave splashes in rough water can lead to insidious loss of heat and serious impairment of judgement. Hypothermia may occur even in relatively warm water if exposure is prolonged ( Hypothermia, p. 622). Both wet and dry suits are effective at reducing cold shock following sudden immersion in icy water, and may save lives under these circumstances.
Diving and jumping into water: risks spinal, neck, and head injuries, depending on depth of water and submerged objects.
Surfing: because surf is best in shallow waters, this sport is associated with an increased risk of head or spinal injuries and lacerations from submerged objects.
Kite surfing/windsurfing: carry similar risks to surfing but with the added risk of joint dislocations and back injuries. Injuries secondary to line entanglement are a particular hazard for kite surfers.
Kayaking: occasionally craft can be caught between rock and current, or continuous battering by surf prevents ‘righting’.
Swimming: swimmers, surfers, and small craft risk being caught in currents and pulled into areas of water they do not want to be in. People often overestimate their ability, risking cramps, hypothermia, and fatigue.
Time of day: fatigue at the end of a long day, together with fading light increase the risk of accidents at dusk.
Trekking groups: a slip, fall, or surging wave may unexpectedly lead to a member of a trekking group getting into difficulties in the water. Consider how to deal with this eventuality.
Relaxing and socializing: there is a strong correlation between alcohol and drowning; tragedies have occurred when a group has been relaxing at a beach resort following a successful expedition.
Water-borne infections
Hepatitis A ( Hepatitis A, p. 33).
Weil’s disease (leptospirosis)—bacterial disease transmitted in the urine of rats and found in stagnant or polluted water. Urban canoeists are particularly at risk ( Leptospirosis, p. 471).
Onchocerciasis: filarial worm spread by flies, causing ‘river blindness’ in the tropics ( Onchocerciasis (river blindness), p. 494).
Schistosomiasis (‘bilharzia’)—the animal vector is aquatic snails, often found in the tropics in still water or reeds ( Schistosomiasis (bilharzia), p. 498).
Malaria ( Malaria, p. 480).
Other causes of GI upset. Common causes of diarrhoea include Shigella, Salmonella, and Campylobacter ( Diarrhoea and vomiting, p. 398).
Hazardous wildlife
(Also see Chapter 17.)
Fish: lionfish, stonefish, weaver fish, candiru, sting ray, sharks.
Mammals: hippopotamus, polar bears, seals.
Reptiles: alligators and crocodiles.
Coral.
Jellyfish.
Anemones.
Birds.
Snakes.
Resource
Beachsafe website: 
http://beachsafe.org.au/surf-ed
Immersion and drowning
Definitions (World Health Organization)
Drowning is the process of experiencing respiratory impairment from submersion or immersion in a liquid medium such that normal breathing is prevented. The outcomes of drowning may be death, morbidity, or recovery.
Immersion implies that at least the airway and face are under the water, though the rest of the body may be floating.
Submersion requires that the whole body be below the surface of the fluid.
Aspiration is the process of solids or fluids entering the lungs.
Whether the casualty survives or not, they have been involved in a drowning incident. No significant physiological difference exists between salt water and fresh water aspiration. The terms ‘wet drowning’, ‘dry drowning’, ‘near drowning’, and ‘secondary drowning’ are no longer used.
Hazards of water
Cardiac arrhythmias may occur as a result of a fall into cold water. The elderly and anyone with a history of hypertension or ischaemic heart disease are particularly at risk. Recently the concept of ‘autonomic conflict’ has been proposed as a cause of sudden cardiac death in water at any age. This involves simultaneous sympathetic (fear/anxiety upon sudden immersion, cold shock response to peripheries) and parasympathetic (dive reflex from cool water on the face) discharge converging on the myocardium and precipitating arrhythmias.4
Swim failure: very cold water can cause violent shivering, muscular in-coordination, and gasping, which combine to prevent effective swimming and reduce ability to keep the head above water. Wet suits, dry suits, or habituation to cold water reduce this response.
Hypothermia develops during prolonged immersion and is a common cause of death following shipwreck after initial cold shock responses have dissipated. Often the core body temperature will not drop significantly in the first 30 min but survival time in cold water is a matter of minutes for an unsupported, unprotected individual. This can be extended to hours by use of an immersion suit and buoyancy aid, and days in a covered life raft.
Wave splash: those close to the surface can aspirate water following the slap of a wave on the face. Turn your face away from waves; some survival jackets include face splashguards.
Accidental immersion: being able to swim does not protect you from drowning if you are fully clothed and carrying a heavy rucksack. During river or rope-bridge crossings, balance the risk of loose straps and a wobbly rucksack against the need to escape from the pack if you fall or are swept away.
Flush drowning is continuous buffeting by a strong current so that the victim is unable to breathe properly in between waves.
Immersion
There are four phases following immersion into water below the thermoneutral temperature of 30oC (see Fig. 22.1):
Responses to immersion.
Initial response.
Short-term response.
Long-term response.
Post-immersion response.
The colder the water the more dramatic the response. Consider whether a sudden illness such as epileptic seizure or myocardial infarction may have caused the casualty to fall into the water.
Basic resuscitation
Follow international guidelines5 but, as the likely cause is primary respiratory failure, complete five initial breaths and 1 min of CPR before going for help. Approximately 2/3 of drowning victims will vomit—try to keep the airway clear by turning the head to face downhill. This will allow any fluid or vomit to drain away. Overall, only 0.5% of drowning victims will have associated spinal injuries so care of the spinal cord is of secondary importance unless there is a high index of suspicion: head injury or mechanism, e.g. dive into shallow water. If suspected, and enough rescuers are present, extract the casualty horizontally from the water with cervical spine control and log-roll to clear the airway if required. Hypothermia and shock are common, even in tropical climates.
Advanced techniques
An automatic external defibrillator may reveal electrical heart activity if pulses are impalpable.
All post-drowning victims are hypothermic until proven otherwise. Shivering is a good prognostic sign. Warm appropriately ( Field management, p. 624).
Administer high-flow oxygen (if available) during resuscitation and recovery, ideally titrated to pulse oximetry (if available).
Dehydration and acidosis can develop from hypoxia and physiological effects of prolonged immersion. Consider warm IV fluids if available, monitor urine output and respiratory rate.
Acute respiratory distress syndrome (ARDS) can develop up to 72 h post-immersion. It presents as a non-cardiogenic pulmonary oedema caused by the irritation of water in the lungs, and requires hospitalization and ventilatory support.6 If there is likely to be a delay in getting the patient to hospital and the casualty develops wheeze, consider regular hydrocortisone together with salbutamol inhalers/nebulizers, and furosemide.7
Aspiration pneumonia can develop later. Antibiotics are usually not required, but prophylactic antibiotics may be appropriate in remote areas, or if the casualty shows signs of fever or sepsis. Consider other fungal or parasitic pathogens if aspirated water was potentially dirty, e.g. ditches, sewers or frequented by rodents (see Leptospirosis p. 471).
All survivors of an immersion incident who may have inhaled water should be triaged to ascertain whether they require admission to a hospital capable of offering advanced respiratory support.
A cough post immersion is not a criterion for admission.
Immediate, (as is practicable), admission is required if a cough is present plus one of: productive sputum or ‘foam’, fever, respiratory distress, or cardiac compromise.
Discontinuing resuscitation and rescue attempts
Good quality survival following prolonged immersion can occur, particularly if water is very cold. Attempt basic resuscitation wherever practical and, if possible, evacuate to a hospital capable of advanced re-warming techniques such as cardiopulmonary bypass. After prolonged hypothermia or cardiac arrest, the core temperature should be re-stabilized at 33°C for 72 h before returning to normothermia.
Survival is extremely unlikely if the victim has been submerged (head under) for >30 min in water warmer than 6oC, and >90 min in water <6oC. Expeditions in remote areas should attempt to resuscitate and re-warm a casualty, but will have to adopt a pragmatic approach to ceasing resuscitation attempts (see also Hypothermia, p. 622).
Resources
Surf Life Saving GB: http://www.surflifesaving.org.uk
Transport Canada. Marine Safety: http://www.tc.gc.ca/MarineSafety
Canoeing and kayaking
Canoes are open boats manoeuvred by sitting or kneeling using single-blade paddles, but the term is often used generically to include kayaks, which are enclosed craft, paddled sitting using a double-blade paddle. Kayaks are more manoeuvrable and manage waves and white water better. Sea kayaks can carry reasonable loads and manage longer trips; river kayaks have limited space for gear and food. Canoes are more suitable for lakes or slow rivers and can carry heavy loads. These craft may be used to explore remote areas, for other recreations such as fishing, or for the challenge of white water trips.
Preparation
Fitness appropriate to the challenge is vital, especially for multiday trips, which are far more exhausting than day excursions. Any fitness training is worthwhile, but most important preparation is ‘time in boat’.
Good paddling and rafting technique reduces the risk of shoulder and back injuries.
Learn to lift weights and loaded boats safely and efficiently.
Team working is vital for a successful expedition. Disputes about goals are a major factor in expedition ‘failures’. Before you go, it is important to establish what you are all in it for—a challenging paddle, a holiday, or something in between?
Consider immunizations against waterborne hepatitis A and polio, also rabies for remote areas and oral cholera (Dukoral®) for some urban centres.
Consider if other treatments such as antimalarial drugs are required.
Get treatment for dental problems, back pain, and piles before departure—if these conditions worsen on the trip, they may force you to abandon the trip or may spoil the journey for your mates.
Accommodation and campcraft
Commonest site for accidents, especially if alcohol is involved.
Acceptable sites can be infrequent and may have limited space for camping. Keep gear, especially boats, above high-water mark.
Lightweight tents are used but with limited space in boats for gear, if weather is warm and biting insects not an issue, save weight by using a lightweight tarpaulin for the group, propped up with paddles and throwlines, and/or bivi bags. Down sleeping bags pack small, but are unreliable if damp. Double bag them, or choose the bulkier artificial fibre bags that retain insulation even if damp.
Heat, light, and fuel
Carry fuel, driftwood makes good fires but may not be available.
Gas canisters are light, but always check local availability as they cannot be taken on aircraft.
Kerosene or petrol will probably be available locally, but quality may vary and soot may clog stove nozzles: take several prickers. Fuel bottles must have perfect seals to prevent smelly contamination and damage of other gear and food.
Water supplies
(See also Water purification, p. 102.)
Sea, rivers, and lakes are recipients of sewage and, in urban areas, street run-off with oils and animal and human faeces.
At sea on coastal trips, it is vital to know the next source of fresh water. If location unknown prior to departure, take adequate water. Water bladders with pipe to mouth are useful for daytime paddling. Consider a flask of boiled water, useful for a brew in the first half of the day, and as a source of clean water for cuts etc.
In river kayaks, a filter can be bulky and may develop unseen breakages and leaks. Canoes, rafts, and sea kayaks, have more space to carry filters. An alternative to a filter is to use chlorine dioxide or iodine, easy to carry as an emergency supply. Take sufficient dropper bottles with you to fill up with iodine.
Lakes and coastal seas may develop harmful algae blooms (HABs), containing toxic or otherwise harmful phytoplankton such as dinoflagellates of the genus Alexandrium and Karenia, or diatoms of the genus Pseudo-nitzschia. Such blooms often take on a red or brown hue and are known colloquially as ‘red tides’.
Biting insects and snails may be vectors for parasites.
Nutrition
Ensure adequate food and water supplies available during day to counteract fatigue. In remote locations it may be difficult to buy food; expedition rations may then be restricted to less palatable freeze-dried or tinned alternatives. Keep food and water cool by storing low in the boat’s hull, with heavy items central to maintain balance.
Sanitation
At sea, some carry a marked pee bottle, but its use can be difficult in rough water, and groups may need to raft up. More difficult for women, although some use a ‘slipper’ type bottle.
Faecal matter degrades slowly in toilet pits on beaches. Small or popular beaches can get overloaded unless a management plan is in place. In many North American National Parks you are required to carry out your toilet waste.
Clothing
Wind and water combine to chill the body, so effective protective gear is necessary, but overheating can also be an issue with hard exercise and impermeable fabrics.
Wetsuits tend not to be used in kayaking expeditions—if you’re expecting to get wet, then a drycag is better at keeping you dry and warm, although damaged and leaking drycags are hard to repair effectively. If you are only expecting exposure to spray, then wear a comfortable paddling top cuffed at neck and wrists over a synthetic or merino wool vest. Dry suits can cause overheating, chafing, become punctured, and may be uncomfortable. Following coastal trips wash all kit in fresh water each evening to minimize damage and chafing. Effective UV protection is necessary in sunny places.
Footwear should cope with slippery, rough ground and bearing the weight of boats while the sole must be flexible enough to fit in cramped cockpits.
Spectacles should be tied firmly with thin yachting cord; proprietary cords with quick-fit rubber ends don’t hold them well in turbulent water.
Safety
Get used to wearing buoyancy aids whenever close to water.
Wherever possible in difficult water, ensure there are backup or rescue craft.
Use a buddy system; in bigger groups appoint front and rear paddlers. Split large groups into smaller units.
Work as a team and know where everyone is. Communication within the group is vital; even small, experienced groups make a point at the beginning and end of each day of having a briefing on the day past and the day to come. All sea kayakers carry waterproof VHF radios for both inter-group and outside contact.
Agree hand signals and methods of communication that will work despite wind or water noise.
When scouting rapids, agree routes and running order with safety crafts or throw lines positioned below rapids.
Helmets, paddles, and cagoules should be brightly coloured, perhaps even using fluorescent tape on dark-coloured gear.
If travelling with a guiding company using their equipment, check the experience, qualifications, and first-aid training of the guides together with the age and serviceability of the vessels.
Self-rescue is important; kayakers should be able to self-right after a roll even in heavy water, and practise other rescue techniques such as towing.
White-water rafting
White-water rafting is an exhilarating active sport usually led by professional guides, who can safely guide novices through reasonably hard rapids. Multiday trips are true river journeys, offering unique access to wilderness areas.
Although white-water rafting may appear dangerous, accident rates are low if basic safety rules are followed. A survey in the USA (West Virginia, 200 injuries) showed that most injuries occur in the raft: 1/3 to the face, 1/3 cuts—especially to the hands, and 1/6 fractures.
Evaluating the raft company
Good companies should run well-organized trips, but local competition can reduce prices to the detriment of safety. Check:
The experience of the guides and their qualifications.
How often they have run the river.
Age and serviceability of the rafts.
Buoyancy aids and helmets provided.
Appropriateness of safety briefing.
Whether another craft (raft or kayak) will accompany your raft.
Preparations
You need to be reasonably fit.
Safer if you can swim, you should certainly not be scared of water.
In developing countries consider hepatitis A vaccination.
Clothing should include a peaked sun cap and good river sandals with either buckles or Velcro® fastening.
Take a small medical kit, including paracetamol, plasters, and sun screen, and iodine for grazes, cuts and emergency water sterilization.
On the water
Use sun-protection.
Drink plenty of clean water to prevent dehydration.
Wear your buoyancy aid whenever you are close to flowing water.
At camps
Sterilize water effectively.
Follow local sanitation rules.
Careful hand hygiene using soap and water or alcohol gel.
Beware of twists and sprains on rocks especially at night.
Beware of the campfire.
Medical problems in small craft
Serious medical issues
Immersion and drowning
(See also Immersion and drowning, p. 688.)
Sudden immersion in very cold water, especially in those less habituated to it, activates the cold shock response: ‘gasp and hyperventilation’, which reduces the time available to attempt a roll and can increase risk of drowning. Above rapids, experienced paddlers often douse their faces in cold water as this may reduce the reflex.
Non-freezing cold injury
(See also Non-freezing cold injury, p. 632.)
Also known as trench foot or pernio, cold injury is possible in very cold waters if feet are immersed in cold water for prolonged periods. May occur during spring rafting especially in high latitudes. Recognized by pain and discoloration of the foot; it can cause prolonged disability.
Hypothermia
(See also Hypothermia, p. 622.)
Clearly a risk with prolonged exposure to water and spray, not necessarily very cold. More likely at end of the day, if people are less experienced, have rolled, or have inadequate clothing. Look out for non-specific, poorer functioning, often in a less experienced team mate, who likely won’t recognize it, and thus you will have to take decisions on their behalf. Cut the day short, camp, rewarm, and feed.
Shoulder dislocation
(For relocation see Shoulder and upper arm injuries, p. 422.)
A particular risk for less experienced paddlers unfamiliar with the power of, and the reaction times needed, on big water. Once injured the risk of a recurrent dislocation is high (up to 50% in first time dislocations), while a weakened vulnerable shoulder will reduce future capability to deal with difficult waters. Older paddlers with a dislocation tend to injure the rotator cuff muscles surrounding the shoulder joint. Dislocation is common when the paddle arm is lifted high and forcibly abducted: as when bracing against a wave, or during an imminent capsize. Proper paddling technique involves keeping the hands low and not reaching too far to the side.
Head and neck injuries
May occur as a result of:
Collisions with paddles or other crew members.
Collision with overhanging vegetation.
Colliding with a rock in the water after fall from craft; if swimming, point your feet downstream or towards any rocks.
Common medical problems
Seasickness
(See also Seasickness, p. 718.)
May be debilitating and hazardous during rough water paddling. Risk factors include fatigue, cold, fear, and watching compass regularly. Sea-sickness is exhausting; sufferers may require rest, food, fluids, and understanding from other expedition members.
Dehydration
An easily overlooked problem particularly common when rafting in the heat, but risk is high even in the Arctic where humidity can be very low. Early signs are vague symptoms such as headache, light headiness, and lethargy and are difficult to recognize unless you are on the lookout for them. Some people avoid drinking much during the day to reduce toilet trips, but then rehydrate during the evening; a risky strategy unless you are very aware of your fluid status.
Back, neck, and muscle problems
Stiff and knotted muscles, especially in neck and between shoulder blades, are common on multi-day trips, and after moving heavy craft. Stretching exercises before and after paddling are worthwhile; together with firm massages of ‘knots’ at end of the day. If non-specific shoulder pain affects your paddling, try keeping the elbow low during the paddle action.
Sea paddlers can get leg strain through constant sitting in the same position. Take the weight off the leg muscles especially in the groin by placing a filled drybag under the knees.
Low back trouble is common in kayakers, especially as the kayaking posture flexes the lower lumbar spine against its natural lordosis. If you suffer from back problems:
Review your flexibility exercises before departure.
Use proper lifting techniques.
Consider lifting aids such as straps or portable trolleys.
Fit a good backrest with effective lumbar or pelvic support.
Back, pelvis, and thigh strains are a risk in contemporary tightly strapped play boats. On the flatter river sections, you should be able to release your legs easily.
Tenosynovitis
Tenosynovitis of wrist tendon is a repetitive strain injury (RSI) due to flexion and extension of the wrist while using a feathered paddle. Pain can be severe and crepitus dramatic. Point tenderness distinguishes this from a non-specific sprain.
Treatment requires complete rest, but on a long journey the paddler may be unable or unwilling to comply. Prescribe an NSAID painkiller such as ibuprofen or diclofenac, or simple analgesic if contraindications to NSAID ( Painkillers, p. 348). A wrist splint or neoprene support may help. Icing (if practical) and elevation in sling may assist recovery.
Alterations to paddling technique may help:
A common cause is gripping paddle too tightly (‘overgrip’), try a looser grip especially when injured wrist is on upper part of stroke.
Use a larger diameter paddle shaft, possibly with cranked shaft.
Change from right to left paddle feather, or vice versa.
Alter feather angle, although this may not help much once pain has started.
Blisters
(See also Blisters, p. 276.)
Water softens the skin. Blisters are fairly common on multi-day trips, even amongst experienced paddlers. Strap tape or moleskin over ‘hot spots’ or early blisters, and change the way you grip the paddle. If blisters burst, treat as a simple cut.
Burns
(See also Burns, p. 280.)
Common when wood fires used. Immediate action to cool the flesh is vital, usually immersing affected area in the water for a period is best. If the burn is severe enough to require a burns dressing, then the challenge on the water is keeping that dressing dry: try duct tape and plastic bags.
Piles
(See also Haemorrhoids (piles), p. 397.)
Common in kayakers, they may be precipitated by both diarrhoea, or by constipation associated with dehydrated foods. Sufferers should consider treatment before departure—they will only get worse.
Ear problems
A common complaint of kayakers is a sensation of ‘water in the ear’ with deafness. This can be caused either by a blocked Eustachian tube (possibly secondary to an upper respiratory tract infection) or by extensive wet wax in ear canal, causing a blockage external to the tympanic membrane. These can be hard to treat. Try to unblock the Eustachian tube:
By inhaling steam.
Using a decongestant such as Actifed®.
Swallowing hard.
Using a Valsalva manoeuvre—but avoid this technique in the case of active nasal infection with green snot as it can make things worse.
You are unlikely to persuade an enthusiastic kayaker to avoid rolling, so it is likely the symptom won’t clear up until after the trip ends. Flying, especially during descent, can be painful if Eustachian tubes are blocked and occasionally leads to tympanic rupture.
Bony exostoses of the ear canal (‘surfer’s ear’) are associated with frequent cold-water impact during years of kayak rolling. When ear canal obstruction exceeds 50%, the risk of infection increases and hearing is impaired. Some experienced kayakers have >80% obstruction. Operations to excise the exostoses don’t always give symptom-free recovery. Prevent by using custom earplugs and a neoprene hood—although these do reduce hearing and therefore safety. Prevention is especially important for athletic youngsters in playboats, who are, at an increasingly younger age, being exposed to frequent immersion in cold water.
Otitis external is an infection of the external ear canal that may be itchy or painful. Common in tropical humid zones, treatment requires good aural toilet, helped by acetic acid (or vinegar) and alcohol. Use an ear plug of cotton wool with an astringent such as Vaseline® or aluminium sulphate. Persistent or severe infections may require antibiotic drops to deal with an acute infection, or steroids if chronic eczema develops.
Cuts, grazes, and skin problems
(See also Wound types and management, p. 272.)
Cuts and grazes should be cleaned with filtered or sterilized water to eliminate risk of contaminating wound with sand or pathogens. Keep a bottle of clean water handy available for such minor emergencies. Cuts on the water have a significant risk of infection. Clean and close as soon as possible with sutures or glue, although glue often wears off after a couple of days. Adhesive skin closure strips are useless in the wet. Uninfected wounds become waterproof after 24 h, but until initial healing has taken place try to keep dry.
Fungal skin infections are common in hot climates, while sun and wind can lead to chapped lips.
Jellyfish stings
(See also Venomous marine animals, p. 566.)
Avoid rubbing skin as pressure increases discharge from sting.
Scrape skin with stiff plastic like an old credit card.
Rinse area well with sea water (fresh water is hypotonic to stinging cells and they will explode in its presence—exacerbating the irritation).
Ice and elevate affected area.
Use an antihistamine (e.g. diphenhydramine) cream or spray.
Don’t pee on the sting—it’s an old wife’s tale.
Burn out and stress
Rushed itineraries lead to chronic mild exhaustion. On challenging sea trips, safe landings can be hours away, but all team members have to be able to the face consequent fatigue and fear. Don’t push weaker members into challenging coastlines or attempting rapids above their skill level. On week-long trips, the nadir of physical fatigue and emotions can come around day 4, then improves. Recognition of variation in moods is important to prevent over-reaction to apparent ‘difficult behaviour’.
Limited medical kit items for small craft
(See also Chapter 28.)
Often lack of space restricts choice of supplies. Pack in zipper plastic storage bags or waterproof container/dry bags, leaving lots of air within the bag or barrel so it floats if displaced in a capsize.
Plastic dropper bottle for iodine solution (one per paddler).
One large bandage (cut to size required).
Suitable painkillers (see Table 28.1).
Multitool with knife and/or scissors (probably in main repair kit).
Antibiotic ear drops (e.g. Betnesol-N®), cotton wool, and petroleum gel.
Hand cream, lip salve.
Seasickness tablets.
Tape—duct tape sticks best, but doesn’t stretch.
Sub-tropical trips—cotton wool, and petroleum gel and consider calamine lotion for sunburn.
Resources
DVDs on skills, rescue, and technological/helicopter/lifeboat rescue: http://www.pesdapress.com
Ferrero F. (
Safety Code of American Whitewater: http://www.americanwhitewater.org/content/Wiki/safety:start
