Whitewater Medicine and Rescue

Chapter 45 Whitewater Medicine and Rescue

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Rafting, canoeing, and kayaking have become the third largest outdoor recreation industry in the United States.12,54 Participation in canoeing and kayaking (including flat-water paddlers) rose from 16.7 million in 1994-1995 to 22.6 million in 1999.58 According to the Outdoor Foundation, participation in kayaking is increasing at a rate of 23% per year.56 Kayakers are almost 70% male, whereas the male-to-female ratio of rafters is somewhat more reflective of the U.S. population at 55% male and 45% female.55,57,73

Kayaks and rafts are also used by law enforcement officers, park rangers, and game wardens to patrol and manage their territories.45 New equipment designs have opened up more difficult rivers for exploration and commercial recreation.50 The number of river-related accidents and deaths has increased as paddlers with innovative boats and improved skills challenge the boundaries of whitewater rivers. The American Canoe Association reports that about 130 whitewater fatalities occur each year.73 This chapter examines the unique and dynamic hazards associated with rivers and whitewater paddling. Safety equipment, accident prevention, common injuries, environmental hazards, medical management, and swift-water rescue techniques are reviewed.

Historical Perspective

Whitewater boating as a recreational activity began in the United States in earnest during the late 19th century, when adventurers attempted to emulate Major Wesley Powell’s Colorado River expedition by rowing boats down many of the West’s large rivers.40 These heavy wooden boats were replaced by inflatable rafts after World War II, when surplus neoprene assault boats and life rafts became available for civilian use.5 In 1956, one of the members of the most affluent business families of America, John D. Rockefeller, built a resort and offered one of the first rafting trips in the country. In the 1960s and 1970s, exclusive whitewater rafting companies were formed, including Becker-Cooke Expeditions, Hatch River Expeditions, and Slickrock Adventures. In 1966, fewer than 500 people boated the Colorado River through the Grand Canyon in an entire year. Now, the figure sometimes exceeds 500 per day.40

Rafting did not become popular in the eastern United States until the early 1960s. In 1968, commercially guided raft trips were offered for the first time on the New River in West Virginia.76 The Chattooga River in Georgia attracted many rafters after the movie Deliverance was filmed there in 1971. The Youghiogheny River in Pennsylvania and the South Fork of the American River in northern California have become the two most heavily rafted rivers in the country.

The first kayaks were made from wooden frames covered in sealskin and used by the Inuit people in the Arctic regions of Alaska and Canada. They included a small hole in the middle of the craft in which the user could sit and were primarily used for hunting. In the 1950s, fiberglass was introduced, and in the 1970s, Kevlar was added to make kayaks both lighter and stronger.

A major innovation in kayaking was development of the plastic kayak, first manufactured in 1972 by the Holloform Company76 (Figure 45-1). The plastic kayak empowered paddlers to run steeper and rockier rivers, because plastic boats were much less likely to break if they impacted rocks. Most recreational whitewater kayaks are now made of molded polyethylene plastic, which does not break apart but has the potential to fold when broached or pinned, trapping the paddler.

The hulls, or bottoms, of kayaks have undergone significant changes during the past 5 years. Older-model kayaks had rounded bottoms, or displacement hulls. Most whitewater kayaks today have flat bottoms, or planing hulls. The flat bottom makes the kayak more stable, both on its bottom and its sides. A rounded bottom rocks in the water from side to side, whereas a flat bottom does not. Newer boat technology, combined with shorter kayaks and more advanced paddling skills, allows better maneuverability in tight, steep rapids and is pushing the limits of navigable rivers. Even Niagara Falls has been successfully run by a kayaker.

Modern interest in canoeing and kayaking for recreation and sport was brought about by John MacGregor, who designed the “Rob Roy,” a canoe he based on sketches of Inuit canoes and kayaks, in 1845. MacGregor formed the Canoe Club in 1866 with other canoe and kayak enthusiasts, and they brought about competitive canoeing with their first regatta in 1873. Kayaking was first included in the Olympic Games in Munich in 1972.

Technological advances have revolutionized whitewater rafting. Electronically welded plastic has largely replaced rubber as the primary material used in raft construction, making the vessels lighter, stronger, and easier to repair. Self-bailing rafts, introduced in 1983, are now ubiquitous and provide greater maneuverability, allowing rafters to run rivers previously considered too difficult and dangerous. Unfortunately, greater mobility has been paralleled by an increase in the number of accidents occurring far from medical care.

Rafts come in several different forms. In Europe, the most common is the symmetric raft steered with a paddle at the stern. Other types are the asymmetric, rudder-controlled raft and the symmetric raft with central helm (oars). Rafts are usually propelled with ordinary paddles and typically hold 4 to 12 persons. In Russia, rafts are often handmade and catamaran style, with two inflatable tubes attached to a frame. Pairs of paddlers navigate on these rafts. Catamaran-style rafts have become popular in the western United States, but are typically rowed instead of paddled.

The enormous popularity of rafting and kayaking has led to exponential growth of professional guide services. In 1990, 35 million people were taken down U.S. rivers by commercial companies.73 Faced with increased competition, guide services have been leading inexperienced clients with little formal training and few practical skills into difficult and dangerous rivers (Figure 45-2). In the summer of 1988, five U.S. executives died after their raft flipped on the Chilco River in British Columbia. One of the survivors was reported to have said, “We looked at white water as sort of a roller coaster ride.”71

Morbidity and Mortality

Deaths are relatively rare in whitewater sports. In Colorado, fewer people die while engaged in rafting, canoeing, and kayaking than in climbing, bicycling, and skiing. Figures compiled by the Colorado Department of Public Health and Environment showed that during a 3-year period ending in 1995, 69 people died while climbing or hiking, 36 while bicycling, and 32 while snow skiing. Rafting, canoeing, and kayaking incidents, by comparison, resulted in 19 fatalities during that same time period (Table 45-1). A report from American Whitewater (AW) in 2000, based on data from 30 managed rivers from 1994 to 1998, placed the fatality rate of rafters, canoeists, and kayakers at 0.87 per 100,000 user-days.79 The fatality rate for kayakers alone was calculated to be 2.9 per 100,000 participants. The fatality rates of other outdoor sports are listed in Table 45-2. Injury rates for kayaking and rafting are 3 to 6 and 0.26 to 2.1 per 100,000 boating days respectively.26 Acute injuries in kayaking are usually due to the transferred force of water on the upper extremity, most often the shoulder, or the impact on an object while swimming out of the boat.

TABLE 45-1 Recreational Fatalities in Colorado, 1993-1995*

Activity Rank Fatalities
Climbing/hiking 1 69
Bicycling 2 36
Snow skiing 3 32
Swimming 4 25
Canoeing/kayaking/rafting 5 19
Horseback riding 6 18
Boating/water skiing 7 13
Fishing 8 11
Hunting 9 6

* Two hundred fifty-two deaths were the results of recreational activities.

Data from Colorado Department of Public Health and Environment.

TABLE 45-2 Fatality Rates of Different Activities

Activity Fatality Rate Per 1 Million Participant Days
Kayaking 8.7-2.2
Rafting 4.5-8.7
Trekking 5-15
Skydiving 8.7
Scuba diving 3.1
Alpine skiing 0.57
Driving 152 (1 day of driving is 100 miles)

Modified from Fiore DC: Injuries associated with whitewater rafting and kayaking, Wilderness Environ Med 14:25, 2003.

A retrospective analysis of injury reports submitted by commercial rafting outfitters to the West Virginia Division of Natural Resources from 1995 to 1997 revealed a total of 200 injuries, with a resulting overall injury incidence rate of 0.263 per 1000 rafters. The average age of injured persons was 33.14 years; 53.3% were male, and 59.8% had previous rafting experience.77 Founded in 1954, AW is a national nonprofit organization that maintains the Accident Database, which is a comprehensive compendium and analysis of whitewater accidents and close calls. The analysis provides the foundation for the AW Safety Code, which outlines whitewater safety guidelines applicable to all skill levels.3

The body parts most frequently injured during rafting mishaps are the face (33.3%), including the eye (12.1%), mouth (6.6%), other facial parts (5.1%), nose (4.5%), and teeth (4.0%); followed by the knee (15.3%); arm, wrist, or hand (11.6%); and other parts of the leg, hip, or foot (10.5%). The most common injury types are lacerations (32.5%), sprains or strains (23.2%), fractures (14.9%), contusions or bruises (9.8%), and dislocations (8.2%). Most injuries occur in the raft as a result of collisions among passengers, being struck by a paddle or other equipment, or entanglement of extremities in parts of the raft.77 Because most injuries occur in the raft and involve the face, accident-preventive measures include attaching face protection to paddling helmets and carrying fewer passengers per raft.

In the summer and fall of 2000, a survey was distributed to whitewater canoe and kayak paddlers at riverside, through paddle club bulletins, and by the Internet. Three hundred nineteen surveys were returned, reporting 388 acute and chronic injuries. The shoulder, wrist, hand, and elbow were the most common sites of injury. Sprain or strain injuries were the most common (26%), followed by laceration and contusion (17% each). Tendinitis was the most common chronic injury (44%), followed by sprain or strain (27%). Giardia infection was reported in 14%.63 Most injuries occurred while the kayaker was still in the boat (87%). Striking an object was the most common mechanism of injury (44%), followed by traumatic stress and overuse (25% each).27

Paddling Equipment

The dynamic and unpredictable nature of rivers can turn any mishap into a tragedy. For this reason, the initial mission of whitewater medicine is to emphasize safety and accident prevention.

According to the U.S. Coast Guard’s boating accident statistics, the most common factor contributing to whitewater-related deaths is failure to wear a personal flotation device (PFD, or life jacket).73 Exposure to cold river water can stimulate respiratory and cardiovascular reflexes, making it difficult for a swimmer to keep his or her head above water (maintain freeboard).42 The Coast Guard is charged with regulating and testing life jackets and classifies PFDs into five types. Of these, only two types are commonly used in whitewater sports.

The type III PFD, a vest-type jacket favored by most paddlers, permits greater mobility and comfort. The Coast Guard requires that type III PFDs have a minimum of 7 kg (15.5 lb) of flotation (lift). Because most adults effectively weigh between 4.5 and 5.4 kg (10 and 12 lb) in the water, this allows at least 1.6 kg (3.5 lb) of effective required buoyancy.

Type V PFDs are used by commercial outfitters because they provide greater flotation and are constructed asymmetrically, with more than one-half of the jacket’s flotation distributed in the front. This is supposed to turn an unconscious wearer face up. Although this may be true in calm water, it does not work reliably in swift water.

A PFD should fit snugly and not ride up over the head when a person is in the water. Because even a well-fitting life jacket can be pulled off by turbulent water, some manufacturers now include crotch straps as an added safety feature. Testifying before a congressional subcommittee, the president of the National Transportation Safety Association cited the Chilco River accident to support his contention that crotch straps be made mandatory on all whitewater-use life jackets. Several survivors reported that their life jackets rode up over their heads and did not keep their faces above water.

Life jackets with built-in rescue harnesses, pioneered by the Europeans, are now widely available in the United States. A typical harness system uses seatbelt webbing threaded through a metal retainer, then run into a plastic cam-lock buckle with a toggle. The toggle allows the user to find the buckle in whitewater. To release the system, the user pulls the toggle, opening the buckle and allowing the webbing to slip through the retainer and release. A D-ring mounted on the back of the jacket provides a point for clipping in a rope (Figure 45-3). This quick-release belt allows the wearer to attempt a strong swimmer rescue and also to get free of the tethering line quickly in an emergency.

Beyond flotation, life jackets have other benefits that make them highly useful in wilderness settings. Their insulating properties help prevent hypothermia. The closed-cell foam flotation material acts as thoracic padding during falls on slippery rocks or when swimming in rapids after exiting the craft. Life jackets also make excellent improvised splints; they can be fashioned into cervical collars, cylindric knee braces (Figure 45-4), or padded ankle stirrups.

The AW Safety Code recommends the use of helmets at all times in kayaks and canoes, and in rafts and other craft when attempting rapids of class IV or greater difficulty. Surveys have shown that head trauma after capsizing constitutes 10% to 17% of all kayaking accidents.45,75 Whitewater helmets are typically crafted from stiff materials such as carbon fiber and Kevlar; a few manufacturers are also using polycarbonate prototypes. Unfortunately, paddling helmets have not been subjected to testing by any certifying entity, such as the American Society for Testing and Materials (ASTM). The Whitewater Research & Safety Institute, Inc. (WRSI), a nonprofit foundation dedicated to making whitewater recreation a safer sport, initiated the Whitewater Head Impact Protection (WWHIP) Project in 2002 in collaboration with Johns Hopkins University’s Bloomberg School of Public Health (http://www.jhu.edu/news_info/news/home02/may02/helmet.html). A by-product of WRSI’s work is the creation of a prototype helmet that represents the culmination of their research.78

Placing adequate barriers between the human body and environment is of paramount importance in aquatic sports. Functional, insulated clothing should be considered a mandatory safety item to prevent hypothermia. Cotton is a poor choice for river wear; it loses all of its insulating properties when wet and dries slowly. Newer synthetics, such as polypropylene and polyester pile, absorb no more than 1% of their weight in water and maintain thermal insulating qualities when wet.41 When combined with a nylon or Gore-Tex paddling jacket, a synthetic underlayer provides effective protection from cold and wind.

Wet suits, previously considered to be optimal garments for paddlers in extreme conditions, are stiff and somewhat constricting.1 The dry suit, with tight-fitting latex seals at the wrist, ankle, and neck, is the new gold standard for cold-water boating. By sealing water out and preventing evaporative heat loss, the dry suit can keep a paddler warm even during winter conditions.31

Overheating is occasionally a problem with dry suits. Recently, a dry suit contributed to profound and unexpected hyperthermia in a kayaker who had suffered a submersion injury in cold water.10

River Hazards

The International Scale of River Difficulty grades rivers and rapids as classes I to VI. An American version of this rating has been adopted by the AWA for most U.S. rivers72 (Box 45-1). Some western rivers use the Grand Canyon System, which rates rapids on a scale from 1 to 10. Neither scale is a truly objective standard; individual and regional variations are common, and the margin of difficulty for a particular rapid may differ significantly for kayaks and rafts. Unfortunately, important safety parameters, such as water temperature, remoteness, and evacuation potential, are not taken into consideration.

BOX 45-1

American Version of the International Scale of River Difficulty

From Safety Code of the American Whitewater Affiliation. http://www.americanwhitewater.org/content/wiki/safety.start?#vi.

The difficulty of a river generally increases with the volume and average gradient of flow. The volume of water in a river is usually expressed as a measure of cubic feet per second (cfs). This is the amount of water moving past a certain point during a given period of time. The volume of a river can be determined by multiplying the width by the depth by the speed of the current. For example, a channel 10 feet deep and 20 feet wide moving at a velocity of 5 feet per second (fps) equals a volume of 1000 cfs. As the water level rises, its speed and power increase exponentially, raising the difficulty of most rapids.5 When the speed of the current is doubled, the force of the water against an object in the current is quadrupled; that is, the force of the current increases as the square of its speed. Occasionally, however, a rapid becomes easier as the added water submerges hazardous obstacles. Gradient is the amount of drop between two points and is expressed as feet per mile. The steeper the gradient, the faster the water moves.

Not all water flows downstream. The most common upstream flow is an eddy, which is created when water flows around an obstacle. The water piles up higher than the river level on the upstream side of the obstacle, whereas the water on the downstream side is lower. Water flows around the obstacle then back toward it to fill in the low spot. The line between the upstream and downstream current is the eddy line. Eddies are one of the most important features of the river for boat maneuvering and rescue. Exiting the main current by pulling into an eddy allows the paddler to stop the descent and safely scout the next rapid. It also provides a location for a paddler to set up rescue for his or her companion upstream.

Hydraulics, also known as holes, reversals, rollers, suck-holes, and pour-overs, are the most common hazards in rivers. A hydraulic is created when water flows over an obstacle, causing a depression that produces a relative vacuum within which the downstream water recirculates (Figure 45-5). The water below a hydraulic is typically very aerated and presents a white, foamy appearance. Rafts and kayaks can be turned upside down by the force of a hydraulic, and if the reversal currents are strong enough, crafts and people can become trapped in the recirculating flow. When proceeding into a rapid that contains a hazardous hydraulic, one of the group should preset a rope below the hole to facilitate rescue.

Hydraulics release water downstream from beneath the surface. This may be the only avenue of escape for a swimmer. Escape from a strong hydraulic may require a person to stay submerged and to resist the urge to return immediately to the surface. Surfacing too early can result in recirculation. Fortunately, most hydraulics eventually release people regardless of what action they take.

Novice paddlers often misjudge the force of hydraulics. It is not the height of the drop that generates the recirculating power but rather the shape and angle of the obstruction, combined with water volume and adjacent eddy currents. A “smiling” hydraulic has its outer edges curving downstream, so that the recirculating water feeds out into the main current and is thus easier to escape. In a “frowning” hydraulic, the outer edges curve back upstream into the center of the hydraulic, making escape much more difficult.

Low-head dams or weirs form massive hydraulics with enormous recirculating potential. Unlike natural hydraulics, these human-made structures form hydraulics all the way across the river, leaving no escape routes. In the Binghamton Dam disaster of 1975, a 4-m (13.5-foot) Boston whaler with a 20-horsepower engine was pulled into a hydraulic while attempting a rescue, resulting in the deaths of three firefighters.69

Undercut rocks are boulders or ledges that have been eroded just beneath the water surface. These usually occur on geologically older rivers. They can be difficult to recognize and pose significant risks for entrapment and drowning, even in class II rapids.

The potential for entrapment can also occur when swimmers attempt to stand up and walk in swift-moving currents. A foot can become wedged in an undercut rock or between rocks beneath the surface, causing the victim to lose his or her balance and fall face down into the river (Figure 45-6, A). With the foot entrapped, the victim cannot regain an upright or even face-up position. This type of mishap has caused drownings in water less than 3 feet deep.

A swimmer in a rapid should assume a supine position, with feet at the surface and pointed downstream to serve as shock absorbers. This position minimizes the potential for both foot entrapment and head and neck trauma (see Figure 45-6, B).

Strainers are obstacles, such as fallen trees, bridge debris, or driftwood, lodged between rocks or jutting out from the shore, that allow water to pass through (sieve effect) while trapping the swimmer or boater. Flooded rivers, a favorite of expert boaters, often develop many new strainers as riverbank debris is washed into the flow. In the summer of 1987, five paddlers drowned when their raft struck a large strainer on Canada’s Ellaho River.71 Negotiating a strainer requires special tactics. The safest option for the swimmer is to swim aggressively into the strainer head first rather than feet first, and then attempt to climb over the debris (Figure 45-7, A). Approaching a strainer feet first may lead to underwater entrapment (Figure 45-7, B).

Man-made hazards can also pose a threat to river runners. Bridge pilings, submerged automobiles, dams, and low-hanging power lines can pin or injure boaters.

A broach occurs when a boat wraps sideways around an obstacle or when both bow and stern become stuck on separate obstacles simultaneously. Common obstacles include boulders, trees, bridge pilings, and ledges protruding from canyon walls. Drowning can occur if the paddler leans upstream away from the obstacle and flips upside down while still broached or if the boat collapses and entraps the victim (Figure 45-8).

A vertical pin happens when a kayaker plunges over a drop and the end of the boat becomes trapped between rocks beneath the surface. The force of the water can fold a plastic kayak over on itself, trapping the occupant upside down beneath the surface (Figure 45-9).

A survey of 365 members of AW revealed that 33% of serious kayaking incidents and 41% of open canoeing mishaps involved either pinning or broaching75 (Table 45-3). In a separate survey of 500 paddlers between 1989 and 1993, 42% of kayaking fatalities resulted from vertical pins, broaches, or entrapments in strainers.

TABLE 45-3 Serious Whitewater–Related Incidents

Incident Type No. of Incidents Percentage of Accidents
Vertical pin entrapment 18 8
Broach entrapment 46 21
Rock sieve entrapment 16 7
Undercut rock entrapment 23 10
Recirculation in hydraulic 47 21
Long swim 42 19

From Wallace D: Scary numbers and statistics: Results of AWA close calls and serious injuries survey, Am Whitewater: J Am Whitewater Affiliation 37:27, 1992.

Kayak construction can have important safety implications in both broach and pin situations. The force of the current against the deck of the boat or back of the paddler can make it impossible for the victim to extract his or her legs and escape. Boat makers have developed kayaks with larger cockpits that make it easier to raise the knees out and escape the craft. Transverse bulkhead-type foot braces have replaced pedal-type braces to prevent the kayaker from being shoved forward in the boat. This feature ensures the escape potential offered by larger cockpits. One of the compromises of the larger cockpit, however, is that the spray skirt is more likely to come off in turbulent water.

Submersion Accidents

Almost all fatalities on rivers result from submersion. Each year, the River Safety Task Force of the American Canoe Association compiles accounts of drownings and other accidents. Every 3 years, it publishes the River Safety Report, which chronicles and analyzes these accidents.697173

Most submersion fatalities occur after paddlers unexpectedly swim from their boats or become trapped in them underwater. The exact cause of drowning often remains unclear and is inexplicably blamed on immersion hypothermia. Although hypothermia induces impaired judgment and coordination and may be an important contributing factor, immersion hypothermia is probably never the sole cause of death.77 Studies by Hayward and others have shown that seminude subjects are able to maintain normal core temperatures for 15 to 20 minutes in 10° C (50° F) water.33,34 Continuous immersion for up to 1 hour would be required to produce profound hypothermia.34

Cold-water immersion precipitates drowning by three other mechanisms. Sudden cold-water immersion produces profound cardiovascular and respiratory responses. Reflex sympathetic output can markedly increase blood pressure and heart rate, resulting in lethal arrhythmias.30,42,43

An immediate and involuntary gasp occurs after cold-water immersion. This is followed by hyperventilation.15 Pulmonary ventilation increases up to fivefold because of increased tidal volume and respiratory rate.66 The initial gasp can result in aspiration of water and laryngospasm. Hyperventilation produces respiratory alkalosis with resultant muscle tetany and cerebral hypoperfusion.15 This response can increase the risk for drowning in a person struggling to maintain an airway freeboard in rough water.

The respiratory stimulation produced by cold-water immersion significantly decreases breath-holding duration.35 This fact has enormous implications for kayakers, who must hold their breath while attempting to roll up a boat after flipping upside down. This probably accounts for the unexplained swims by expert kayakers who sometimes fail to right themselves after flipping in cold water. Although some maintain that respiratory and cardiovascular reflexes can be abolished by repeated exposure of the face to cold water just before entering a rapid, there are no scientific data to support this theory of acclimatization.

Peripheral cold-water–induced vasoconstriction exacerbates rapid cooling of muscles and nerves in the extremities, resulting in loss of strength and coordination.66 Ability to swim, maintain freeboard, avoid obstacles, and climb from the river may be greatly impaired.44 Even when the air temperature is warm, paddlers running cold water rivers should wear sufficiently insulated clothing.

The combination of hyperventilation and muscle dysfunction can be lethal for a swimmer in rough water. A PFD helps, but it does not prevent even small waves from submerging a swimmer’s head.29 These dangers make it imperative to preset safety systems in significant rapids and to rescue swimmers first. Safety kayaks with enhanced buoyancy are recommended on commercial raft trips because they provide additional flotation for clients who fall overboard.

Unfortunately, paddlers have drowned when their companions chased after equipment, assuming that the swimmer could climb out of the river without assistance.70,72

The main treatment for a submersion incident on a river is immediate and aggressive initiation of ventilation and oxygenation using mouth-to-mouth rescue breathing. A glove can be modified and used as a barrier shield for performing rescue breathing. Cut the middle finger of the glove at its halfway point and insert it into the victim’s mouth. Stretch the glove across the victim’s mouth and nose and blow into the glove as you would to inflate a balloon. After each breath, remove the part of the glove covering the nose to allow the victim to exhale. The slit creates a one-way valve, preventing backflow of the victim’s saliva (Figure 45-10, online).

Evidence of trauma should be noted and attention given to cervical spine precautions. Contributing and associating factors such as hypoglycemia, seizures, and hypothermia need to be considered. Because apnea usually precedes cardiac arrest, if ventilation is provided, circulatory resumption may occur spontaneously. Abdominal thrusts are not recommended unless the victim has an obstructed airway and cannot be adequately ventilated.

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Sep 7, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Whitewater Medicine and Rescue

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