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Mountaineering and rock-climbing injuries in US National Parks
ORIGINAL CONTRIBUTION mountaineering; recreation, injury
Mountaineering and Rock-Climbing Injuries in US National Parks Mountaineering and rock climbing have become increasingly popular in recent years and involve an estimated 100,000 participants; accordingly, the number ~of climbing-related injuries has also increased. We analyzed 127 climbing-related injuries reported to the US National Park Service in 1981 and I982, 36 (28%) of which were fatal. Falls accounted for 75% of all climbing-related injuries; median length of fall was 91 m for fatal injuries and 9 m for nonfatal injuries. The majority of injuries (69%) occurred while ascending. Falls on snow or ice were longer than falls on rock, and injuries on snow or ice were more Iike]y to be fatal. We discuss considerations and strategies for the prevention of climbing-related injuries. A n e w conceptual model suggests that the methods of traditional mountaineering s Zety programs m a y be of limited efficacy in further reducing the number of climbing-related injuries. [Addiss DG, Baker SP: Mountaineermg and rock-climbing injuries in US national parks. Ann Emerg Med September 1989;i8:975-979.]
INTRODUCTION The popularity of mountaineering and rock climbing has risen dramatically in recent years. The increase in the number of active climbers in the United States to an estimated 100,000~ has been accompanied by an apparent increase in the number of climbing-related injuries. Voluntary reporting of injuries by climbers, park rangers, and rescue groups to the American A/pine Club (AACI has been the major source of climbing-related injury and fatality data since 1948. Since 1970, the AAC has reported a mean of 109 injured climbers and 34 climbing-related deaths per year in the United States. ~ Compared with 25 years ago, the AAC reports three times as m a n y injured climbers and nearly twice as many climbing-related deaths per year, 2 despite significant advances in safety equipment and widely available technical instruction. Much of the serious mountain climbing and many of the injuries occur within the boundaries of the national parks, yet climbing-related injury data from the entire National Park Service (NPS) have not previously been studied. Prevention of these injuries has received little attention in the medical literature, and principles from the modern field of injury control have not been adequately applied to mountaineering and other potentially high-risk recreational activities in which preventive measures are largely voluntary. We present an analysis of mountain-climbing injuries reported to the NPS in 1981 and 1982 and introduce a new model of the factors involved in these injuries~
David G Addiss, MD, MPH* Susan P Baker, MPHt Baltimore, Maryland From the Preventive Medicine Residency Program* and Department of Health Policy and Management,t The Johns Hopkins University, School of Hygiene and Public Health, Baltimore, Maryland. Received for publication November 14, 1988. Revision received May 9, 1989. Accepted for publication May 31, 1989. This study Was supported in part by CDC grant #R49/CCR302486-01, from the Division of Injury Epidemiology and Control, Center for Environmental Health and Injury Control, Centers for Disease Control, Public Health Service, US Department of Health and Human Services. Address for reprints: Susan P Baker, MPH, injury Prevention Center, The Johns Hopkins University, School of Hygiene and Public Health, 624 N Broadway, Baltimore, Maryland 21205.
METHODS A computer printout of data on climbing-related injuries for 1981 and 1982 was obtained from the Safety and Occupational Health Management Information System of the NPS; these were the first years for which computerized data were~,available. The data were extracted from the narrative and coded portions of the NPS DI-134 report form. Statistical analyses were performed using the ?(2 and Mann-Whitney rank sum tests.
18:9 September 1989
Annals of Emergency Medicine
975/125
CLIMBING INJURIES Addiss & Baker
F I G U R E 1. Number of mountain
climbing injuries and deaths by location, US national parks, 1981 and 1982.
50-
INJURIES
45"
m
FIGURE 2. Performance-demand
Fatal 40-
model of injury causationd 1 RESULTS Injuries were reported in 143 persons. Sixteen persons were injured w h i l e w a l k i n g , h i k i n g , or f a l l i n g from trees or stairs; these were excluded from analysis. The remaining 127 injuries occurred in persons who were mountaineering or rock climbing; 36 (28%) of these injuries were f a t a l . T h e m e a n age of i n j u r e d climbers was 27 years; men and boys comprised 91% of the total. Eightyeight p e r c e n t of injuries o c c u r r e d during May through August. T w e n t y - s i x of 311 NPS sites reported climbing-related injuries. Four parks accounted for 58% of reported injuries, and 67% of the fatalities occurred in two parks, Grand Teton and M o u n t Rainier (Figure 1). The climbing surface was determined for 93% of all injuries; 63% of these occurred on rock and 37% on snow or ice. Injuries occurring on snow or ice were significantly more likely to be fatal than injuries on rock; the respective c a s e - f a t a l i t y ratios were 41% and 19% (P < .05). Of 44 injuries on snow or ice, 11 (25%) were caused by avalanche, rockfall, or icefall. In contrast, only two (3%) injuries on rock were due to rockfall (P < .001); in b o t h i n s t a n c e s , the r o c k was dislodged by the climber or a partner. T h e m a j o r i t y of injuries (69%) occ u r r e d w h i l e a s c e n d i n g ; 31% occurred in descent. The case-fatality ratios for ascending and descending injuries were 26% and 33%, respectively; this difference was not statistically significant (by ×2). The cause of injury was obtained from narrative reports for all but six injuries (Table). Falls accounted for 75% of injuries; 43% of these were due to slipping or loss of footing, and for 45%, c i r c u m s t a n c e s of the fall were not specified. Length of fall was recorded for 81 injuries; the range was from 2 to 610 ~ . For fatal injuries, the median length of fall was 91 m (mean, 141 m). In comparison, the median length of fall for nonfatal injuries was 9 m, with a mean of 3t m. (P < .001, Mann-Whitney rank sum test). For injuries resulting from falls 126/976
Non--Fatal
35-
30-
25z 2o-
15-
lo-
5.
o
Tetons
Rainier Yosemite
Joshua
Denali
Other
"Acc dent" Performonce
Time on snow and ice, the median length of fall was 42 m, compared with 9 m for falls on rock (P < .001). W h e n controlled for length of fall, there was no significant difference in the case-fatality ratio for different surfaces. Avalanche or icefall caused 9% of all injuries but 28% of deaths. Nine injuries (7%) were due to exposure to cold or high altitude; these included Annals of Emergency Medicine
six cases of frostbite and three cases of h i g h - a l t i t u d e c e r e b r a l e d e m a . Equipment, w h e t h e r through failure or misuse, was noted as the cause for 6% of all injuries. The type of injury was recorded for 115 injuries (9i%). Thirty-eight (33%) of these were coded as multiple injuries, f o l l o w e d by f r a c t u r e s (29%), sprains (10%), and frostbite (5%). Of the 38 climbers with multiple inju18:9 September 1989
FIGURE 3. The mountain climbing i n j u r y m o d e l of a rock c l i m b in Yosemite, rated 5.8, where the injury event is a fall.
5.9 5.8 5.7
Level of Performance
5.6
Demand
5.5
or Demand
5.4
(Yosemite Decimal Rating)
5,3 ,5.2 5.1
Pitch
Probability of Severe injury Climber
\ 3 ries, 29 had multiple fractures and trauma to internal organs; 21 of these climbers died. Three of the nine remaining climbers had multiple abrasions, lacerations, or less severe fractures; details were not available for the other six. Direct comparison between the NPS and AAC data was not possible because the AAC annual reports include injuries occurring outside the NPS boundaries and do not provide narrative a c c o u n t s of all injuries. However, AAC reported 200 injured climbers and 63 deaths during the study period. 2
DISCUSSION Falls are t h e m a j o r c a u s e of climbing-related injury, and a positive association was noted between length of fall and cas~-fatality ratio. Such an association may seem obvious, yet as De Haven 3 and Snyder4 point out, length of fall alone is an inadequate predictor of injury severity. Particularly in the mountain setting, injury outcome is also influ18:9 September 1989
enced by the angle and type of surface and by the degree to which the fall was slowed by the victim (eg, self-arrest on a snow slope), the climber's roped partner, or impact with surfaces during the fall. An injury occurring on snow or ice was more likely to be fatal than an injury on rockl This may have been due in part to the longer length of falls on snow and ice or to the i n creased prevalence of hazards that are not directly under the climber's control, such as avalanches and icefall. In addition , ice c l i m b i n g is frequently done in remote areas, often at h i g h a l t i t u d e and in s e v e r e weather conditions. A belief common among climbers that descending is more risky than ascending is not supported by these data, which show that 69% of injuries occurred during ascending. If one considers, however, that the descent usually takes a fraction of the time required for the ascent, risk of injury per hour exposed m a y in fact be greater while descending. Relatively Annals of Emergency Medicine
few injuries were reported to have been caused by failure of climbing safety e q u i p m e n t , a finding supported by other studies in w h i c h equipment failure was blamed for 4% to 8% of injuries.5, 6 These NPS data have several limitations and should be interpreted with caution. First , the high casefatality ratio of 28% is similar to that of other studies based on rescue reports or hospital records.6, 7 The data from such studies are not representative of all climbing-related injuries because only the most severe injuries and deaths are usually reported. In comparison, case-fatality ratios of 5% to 9% h a v e been reported in studies based on the more inclusive data of surveys, clinic records, or i n s u r a n c e c l a i m s . S,S,9 S e c o n d , climbing-related injuries during 1981 through 1982 may not b e representative of injuries in the national parks in other years: Third, we were unable to calculate r a t e s of injury because the actual number of climbers in the national parks is unknown. The AAC figure of 100,000 climbers is a rough estimate, but this includes climbing outside the national parks. Climbers in most parks are not required to register; such a requirement may improve estimates of climbers at risk but could be impractical or difficult to enforce in certain areas. Finally, injuries may not have been detected or reported uniformly among the different parks or regions; the apparent variation in rates of injury probably reflects different reporting practices as well as differences in actual risk of injury. Despite these limitations, the NPS Safety and O c c u p a t i o n a l H e a l t h M a n a g e m e n t I n f o r m a t i o n System may be of potential use as a surveillance system for severe climbingrelated injuries in the national parks, a source of complementary injury data for the AAC, and a stimulus for additional studies in specific parks Or climbing areas. Because of the details reported for most cases, the NPS data may also be helpful in understanding the circumstances and prevention of injury. Ongoing injury surveillance data provided by the AAC or NPS are im977/127
CLIMBING INJURIES Addiss & Baker
p o r t a n t for additional descriptive studies and for evaluating the impact of preventive strategies. However, as noted by Haddon 1° for other sports, developing effective strategies to prevent climbing-related injuries will r e q u i r e f u r t h e r u n d e r s t a n d i n g of climbers and their exposure to risk, the environment in which the spor t takes place, and the rules and nature of the sport itself. P r e v e n t i o n of climbing-related injuries has become an increasingly important issue for climbers, NPS officials, and emergency physicians. How best to preserve the essence of climbing while preventing injuries is a matter of considerable debate, especially in view of pending litigation against equipment manufacturers and professional mountain guides, n The unique characteristics of climbing as a sport and the role and limitations of traditional mountaineeri.ng safety measures in preventing climbing-related injury are explored in the following discussion.
PREVENTION OF MOUNTAIN CLIMBING INJURIES: A CLOSER LOOK Injury prevention in the mountain environment is inhibited by several unique factors. Physical isolation, severe weather conditions, and lack of a v a i l a b l e t r a n s p o r t to e m e r g e n c y medical facilities have been cited as increasing the morbidity and mortality associated w i t h climbing injuries. 9 Equally important, however, as noted by Haddon, m is the nature of the sport itself, which is inextricably bound with risk. Three basic characteristics of the sport - risk, performance, and demand should be considered in any prevention program aimed at reducing climbing-related injuries. These characteristics are described in a new model. The basic model, adapted from Blumenthal, 1~ is comprised of two curves: one representing the difficulty or demands of the climb and the other representing the climber's performance, both of which vary over time. A fall or other "accident" occurs when the demands of a particular task exceed the capabilities of human performance and the two curves intersect (Figure 21. Prevention of injury is possible by either reducing the demands of the climb or improving climber performance. Task demands for rock climbing 128/978
TABLE. Cause of mountain climbing injuries, National Park Service Accident Reporting System, 1981 - 1982
Cause of Injury
Fatal Injuries N % of Total
Falls, total Unspecified Loss of footing Anchor failure Into crevasse Fatigue or handhold failure Avalanche or icefall Frostbite Hit by falling rock High-altitude cerebral edema Other, unknown Total
24 12 8 2 1 1 10 0 1 0 1 36
have been quantified in the widely used Yosemite decimal system, which rates the difficulty of a climb f r o m r e l a t i v e l y e a s y {5.0) to ext r e m e l y difficult (5.14). C l i m b e r s c o m m o n l y measure their climbing ability by this scale. Other types of climbing, such as vertical ice, are similarly rated. For a given climb, the model can describe the interplay of factors affecting the demand of the climb and the performance of the climber (Figure 3). The d e m a n d curve, determ i n e d p r i m a r i l y by the Yosemite decimal rating, is increased at high altitude or under poor weather or surface conditions. T h e p e r f o r m a n c e curve is determined by the climber's ability and judgment and is decreased by factors such as dehydration, hypothermia, suboptimal acclimatization, poor physical conditioning, inadequate equipment, fatigue, or altered mental status. An additional curve is included in the new model that describes the probability of severe injury when the performance and demand curves intersect (Figure 3). This curve is dependent on the specific injury event. If the event is a fall, for example, the probability of severe injury will increase with the distance fallen before impact (a function of distance from the ground or above the last piece of protection}, the hardness of the landing s u r f a c e , and i m p r o p e r ropehandling technique on the part of Annals of Emergency Medicine
66
28 0 3 0 3 100
Nonfatal Injuries N % of Total 71 31 33 2 1 4 1 6 3 3 7 91
78
1 7 3 3 8 100
one's climbing partner. Part of the a t t r a c t i o n of mountaineering and other high-risk recreational activities is the occasional near-intersection of demand and performance curves. The risk of potentially severe injury, represented by the third curve, may play a peculiar role in m o t i v a t i n g some climbers. R a t h e r t h a n f o c u s i n g d i r e c t l y on these underlying elements of risk, demand, and performance, mountaineering safety programs have traditionally e m p h a s i z e d three m a i n principles: proper equipment, adequate experience and training, and good judgment. 13 Reducing task demands through engineering and safe equipment design has proved to be a particularly effective passive strategy in preventing injuries. ~4 Passive or automatic protection, such as canoe flotation, requires no effort on the part of the individual using the equipment. Unlike active strategies, which depend on individual behavior (eg, wearing a climbing helmetl, many passive measures focus on reducing t a s k demands. Yet some human endeavors, including climbing, are appealing precisely because they are challenging Itask demands are highl. In contrast to the success of safe product design in preventing injuries in the home and workplace, the introduction of m o d e m climbing equipment, designed for efficiency and safety, has been accompanied by a sharp escala18:9 September 1989
ti0n of climbing standards. R a t h e r than decreasing, d e m a n d s have increased dramatically to parallel the high performance made possible, i n part, by better equipment. Some passive strategies focus on reducing the probability of severe iniury when a fall or other injury event occurs ( r e p r e s e n t e d by t h e t h i r d curve in the m o d e l ) . T h e u s e of automatic-release ski bindings is an example of effective a p p l i c a t i o n of such a strategy. M a n y t r a d i t i o n a l safety m e a s u r e s r e c o m m e n d e d for mountaineers w o u l d r e d u c e i n j u r y severity, but m o s t of these require deliberate action on the part of the individual climber. Proper p l a c e m e n t of protection to reduce the distance of a potential fall, for example, requires both experience and careful attention. Some of t h e s i m p l e s t of these safety measures, such as wearing a chest harness or safety h e l m e t (requiring only infrequent action), are often rejected as unnecessary or bothersome. If advances in c l i m b i n g e q u i p m e n t have neither decreased demands nor diminished risk, w h a t t h e n of the two other m e m b e r s of the " s a f e t y triad": adequate t r a i n i n g and good judgment? Do t r a i n i n g a n d experience decrease m o u n t a i n e e r i n g risk or merely i n c r e a s e c o n f i d e n c e w h i l e risk remains c o n s t a n t - or even increases? There is some evidence to support the n o t i o n t h a t r i s k of i n j u r y is higher among inexperienced or inadequately trained climbers. Investigators have found high proportions of injured c l i m b e r s l a c k i n g e x p e r i ence,2,6,8 but the level of experience for comparable u n i n j u r e d climbers is unknown. Oberli, using n a t i o n a l insurance data from Switzerland, estimates the risk of c l i m b i n g - r e l a t e d death among m e m b e r s of the Swiss Alpine Club to be one t e n t h that of nonmembers, w h o p r e s u m a b l y are less experienced. 9 Injuries associated with d o w n h i l l s k i i n g , a n a c t i v i t y similar in some respects to m o u n taineering, have been shown to be inversely correlated w i t h skiing ability and experience. 1>17 Risk of fatal injury,~ on the other hand, may increase wi~h experience. In a study by Tongue, 18 hang glider
pilots w i t h m o r e t h a n 200 flights Were overrepresented a m o n g the fatalities. As the hang glider pilot gains experience, he a t t e m p t s more difficult maneuvers in more marginal conditions, ~9 a progression n o t unlike that of the m o u n t a i n e e r . Those w h o c l i m b i n t h e H i m a l a y a s are among the most experienced and skillful mountaineers, yet the Himalayan climbing m o r t a l i t y rate is probably the highest i n the world. 20 In potential high-risk sports, as the t a s k - d e m a n d curve approaches the p e r f o r m a n c e c u r v e , j u d g m e n t becomes the crucial m e m b e r of the trad i t i o n a l safety triad. Impaired judgm e n t or climber error was associated w i t h 39% to 50% of climber injuries i n t h r e e r e c e n t studies.S,6, 9 G o o d j u d g m e n t is elusive, n o t ensured by technical training or experience; it is hard to learn and harder to teach. As the popularity of c l i m b i n g cont i n u e s to grow, t r a d i t i o n a l safety principles alone m a y n o t be adequate to p r e v e n t the o c c u r r e n c e of additional injuries. The u n d e r l y i n g elem e n t s and nature of the sport m u s t also be considered. Models, such as the one we present, can be used to evaluate specific climbs or c l i m b i n g areas. Clusters of injuries at a certain point in a climb m a y represent, for example, underrating of that part of the climb. Models m a y also facilitate analysis of factors specific to certain areas that elevate task d e m a n d s or d e c r e a s e c l i m b e r p e r f o r m a n c e . Inc l e m e n t weather, for i n s t a n c e , has played an i m p o r t a n t role i n recent fatalities i n Yosemite, where it is often unanticipated. CONCLUSION Several groups, i n c l u d i n g physicians, search and rescue teams, park officials, and climbers, are currently i n t e r e s t e d i n t h e p r e v e n t i o n of c l i m b i n g - r e l a t e d i n j u r y a n d death. There is a need for i m p r o v e d data, more sensitive models, and thoughtful application of p r e v e n t i v e strategies t h a t d e c r e a s e m o r b i d i t y a n d m o r t a l i t y w i t h o u t v i o l a t i n g the nature of m o u n t a i n e e r i n g . Such strategies developed for m o u n t a i n e e r i n g m a y have additional application to o t h e r p o t e n t i a l l y h i g h - r i s k recreational activities.
The authors thank Kay L Doerr, Safety Specialist, and Stanley T Albright, Associate Director, Park Operations, of the National Park Service, Washington, DC, for their generous assistance in providing the NPS data. REFERENCES 1. Williamson JE (ed}: Accidents in North American Mountaineering •979. New York, The American Alpine Club, 1979. 2. Williamson JE (ed): Accidents in North American Mountaineering 1985. New York, The AmericanAlpine Club, 1985. 3. De Haven H: Mechanicalanalysisof survival in falls from heights of fifty to one hundred and fifty feet. War Med 1942;2:586496. 4. Snyder RG: Man's survivability of extreme forces in free-fall impact, in AGARD Conference ProceedingsNo. 88 on LinearAcceleration of Impact Type. 1971;5.1-5.13 (AGARDCP-88-71). 5. McClennanJG, UngersmaJ: Mountaineering accidents in the Sierra Nevada. Am J Sports Med 1983;Ih160-163. 6. SchussmanLC, Lutz LJ: Mountaineeringand rock-climbing accidents. Phys Sports Med 1982;10:53761. 7. Foray J, Herry JP, Vallet JH, et ah Les accidents de montagne. Chirurgie 1982~108:724-733. 8. Wilson R, Mills WJ Jr, Rogers DR, et al: Death on Denali. West J Med 1978;128:471-476. 9. Oberli H: Der bergunfall, alpines rettungswesen. Z Unfallmed Berufskr 1981;74:3-9. 10. Haddon W Jr: Principlesin research on the effects of sports on health. JAMA 1966;197: 163-166. 11. KennedyM: Moneytalks, nobodywalks (editorial). Climbing 1989;114:6. 12. Blumenthal M, cited in Baker SP: Injury control, in Sartwell PE (ed): Preventive Medicine and Public Health, ed 10. New York, Appleton-Century-Crofts,1973, p 987-1005. 13. Ferris BG: Mountain-climbing safety. iV Engl J Med 1963;268:662-664. 14. Haddon W Jr: Strategy in preventive medicine: Passive vs. active approaches to reducing human wastage. J Trauma 1974;14:353-354. 15. HaddonW Jr, EllisonAE, Carroll RE: Skiing injuries: Epidemiologic study. Public Health Rep 196%77:975~985. 16. Young LR, Oman CM, Crane H, et al: The etiology of ski injuries: An eight year study of the skier and his equipment. Orthop Clin North Am 1976;7:13-29. 17. Criqui MH: The epidemiologyof skiing in~ juries. Minn Med 1977;60:877-880. 18. TongueJR: Hang glidinginjuries in California. l Trauma 1977;17:898-902. 19. KrissoffWB, EisemanB: Injuries associated with hang gliding.JAMA 1975;233:158-160. 20. Koerner M: Risks of climbing. American Alpine News I984;5:8~9.
See related editorial, p 1012 18:9September 1989
Annals of Emergency Medicine
979/129
Mountaineering and Rock-Climbing Injuries in US National Parks Mountaineering and rock climbing have become increasingly popular in recent years and involve an estimated 100,000 participants; accordingly, the number ~of climbing-related injuries has also increased. We analyzed 127 climbing-related injuries reported to the US National Park Service in 1981 and I982, 36 (28%) of which were fatal. Falls accounted for 75% of all climbing-related injuries; median length of fall was 91 m for fatal injuries and 9 m for nonfatal injuries. The majority of injuries (69%) occurred while ascending. Falls on snow or ice were longer than falls on rock, and injuries on snow or ice were more Iike]y to be fatal. We discuss considerations and strategies for the prevention of climbing-related injuries. A n e w conceptual model suggests that the methods of traditional mountaineering s Zety programs m a y be of limited efficacy in further reducing the number of climbing-related injuries. [Addiss DG, Baker SP: Mountaineermg and rock-climbing injuries in US national parks. Ann Emerg Med September 1989;i8:975-979.]
INTRODUCTION The popularity of mountaineering and rock climbing has risen dramatically in recent years. The increase in the number of active climbers in the United States to an estimated 100,000~ has been accompanied by an apparent increase in the number of climbing-related injuries. Voluntary reporting of injuries by climbers, park rangers, and rescue groups to the American A/pine Club (AACI has been the major source of climbing-related injury and fatality data since 1948. Since 1970, the AAC has reported a mean of 109 injured climbers and 34 climbing-related deaths per year in the United States. ~ Compared with 25 years ago, the AAC reports three times as m a n y injured climbers and nearly twice as many climbing-related deaths per year, 2 despite significant advances in safety equipment and widely available technical instruction. Much of the serious mountain climbing and many of the injuries occur within the boundaries of the national parks, yet climbing-related injury data from the entire National Park Service (NPS) have not previously been studied. Prevention of these injuries has received little attention in the medical literature, and principles from the modern field of injury control have not been adequately applied to mountaineering and other potentially high-risk recreational activities in which preventive measures are largely voluntary. We present an analysis of mountain-climbing injuries reported to the NPS in 1981 and 1982 and introduce a new model of the factors involved in these injuries~
David G Addiss, MD, MPH* Susan P Baker, MPHt Baltimore, Maryland From the Preventive Medicine Residency Program* and Department of Health Policy and Management,t The Johns Hopkins University, School of Hygiene and Public Health, Baltimore, Maryland. Received for publication November 14, 1988. Revision received May 9, 1989. Accepted for publication May 31, 1989. This study Was supported in part by CDC grant #R49/CCR302486-01, from the Division of Injury Epidemiology and Control, Center for Environmental Health and Injury Control, Centers for Disease Control, Public Health Service, US Department of Health and Human Services. Address for reprints: Susan P Baker, MPH, injury Prevention Center, The Johns Hopkins University, School of Hygiene and Public Health, 624 N Broadway, Baltimore, Maryland 21205.
METHODS A computer printout of data on climbing-related injuries for 1981 and 1982 was obtained from the Safety and Occupational Health Management Information System of the NPS; these were the first years for which computerized data were~,available. The data were extracted from the narrative and coded portions of the NPS DI-134 report form. Statistical analyses were performed using the ?(2 and Mann-Whitney rank sum tests.
18:9 September 1989
Annals of Emergency Medicine
975/125
CLIMBING INJURIES Addiss & Baker
F I G U R E 1. Number of mountain
climbing injuries and deaths by location, US national parks, 1981 and 1982.
50-
INJURIES
45"
m
FIGURE 2. Performance-demand
Fatal 40-
model of injury causationd 1 RESULTS Injuries were reported in 143 persons. Sixteen persons were injured w h i l e w a l k i n g , h i k i n g , or f a l l i n g from trees or stairs; these were excluded from analysis. The remaining 127 injuries occurred in persons who were mountaineering or rock climbing; 36 (28%) of these injuries were f a t a l . T h e m e a n age of i n j u r e d climbers was 27 years; men and boys comprised 91% of the total. Eightyeight p e r c e n t of injuries o c c u r r e d during May through August. T w e n t y - s i x of 311 NPS sites reported climbing-related injuries. Four parks accounted for 58% of reported injuries, and 67% of the fatalities occurred in two parks, Grand Teton and M o u n t Rainier (Figure 1). The climbing surface was determined for 93% of all injuries; 63% of these occurred on rock and 37% on snow or ice. Injuries occurring on snow or ice were significantly more likely to be fatal than injuries on rock; the respective c a s e - f a t a l i t y ratios were 41% and 19% (P < .05). Of 44 injuries on snow or ice, 11 (25%) were caused by avalanche, rockfall, or icefall. In contrast, only two (3%) injuries on rock were due to rockfall (P < .001); in b o t h i n s t a n c e s , the r o c k was dislodged by the climber or a partner. T h e m a j o r i t y of injuries (69%) occ u r r e d w h i l e a s c e n d i n g ; 31% occurred in descent. The case-fatality ratios for ascending and descending injuries were 26% and 33%, respectively; this difference was not statistically significant (by ×2). The cause of injury was obtained from narrative reports for all but six injuries (Table). Falls accounted for 75% of injuries; 43% of these were due to slipping or loss of footing, and for 45%, c i r c u m s t a n c e s of the fall were not specified. Length of fall was recorded for 81 injuries; the range was from 2 to 610 ~ . For fatal injuries, the median length of fall was 91 m (mean, 141 m). In comparison, the median length of fall for nonfatal injuries was 9 m, with a mean of 3t m. (P < .001, Mann-Whitney rank sum test). For injuries resulting from falls 126/976
Non--Fatal
35-
30-
25z 2o-
15-
lo-
5.
o
Tetons
Rainier Yosemite
Joshua
Denali
Other
"Acc dent" Performonce
Time on snow and ice, the median length of fall was 42 m, compared with 9 m for falls on rock (P < .001). W h e n controlled for length of fall, there was no significant difference in the case-fatality ratio for different surfaces. Avalanche or icefall caused 9% of all injuries but 28% of deaths. Nine injuries (7%) were due to exposure to cold or high altitude; these included Annals of Emergency Medicine
six cases of frostbite and three cases of h i g h - a l t i t u d e c e r e b r a l e d e m a . Equipment, w h e t h e r through failure or misuse, was noted as the cause for 6% of all injuries. The type of injury was recorded for 115 injuries (9i%). Thirty-eight (33%) of these were coded as multiple injuries, f o l l o w e d by f r a c t u r e s (29%), sprains (10%), and frostbite (5%). Of the 38 climbers with multiple inju18:9 September 1989
FIGURE 3. The mountain climbing i n j u r y m o d e l of a rock c l i m b in Yosemite, rated 5.8, where the injury event is a fall.
5.9 5.8 5.7
Level of Performance
5.6
Demand
5.5
or Demand
5.4
(Yosemite Decimal Rating)
5,3 ,5.2 5.1
Pitch
Probability of Severe injury Climber
\ 3 ries, 29 had multiple fractures and trauma to internal organs; 21 of these climbers died. Three of the nine remaining climbers had multiple abrasions, lacerations, or less severe fractures; details were not available for the other six. Direct comparison between the NPS and AAC data was not possible because the AAC annual reports include injuries occurring outside the NPS boundaries and do not provide narrative a c c o u n t s of all injuries. However, AAC reported 200 injured climbers and 63 deaths during the study period. 2
DISCUSSION Falls are t h e m a j o r c a u s e of climbing-related injury, and a positive association was noted between length of fall and cas~-fatality ratio. Such an association may seem obvious, yet as De Haven 3 and Snyder4 point out, length of fall alone is an inadequate predictor of injury severity. Particularly in the mountain setting, injury outcome is also influ18:9 September 1989
enced by the angle and type of surface and by the degree to which the fall was slowed by the victim (eg, self-arrest on a snow slope), the climber's roped partner, or impact with surfaces during the fall. An injury occurring on snow or ice was more likely to be fatal than an injury on rockl This may have been due in part to the longer length of falls on snow and ice or to the i n creased prevalence of hazards that are not directly under the climber's control, such as avalanches and icefall. In addition , ice c l i m b i n g is frequently done in remote areas, often at h i g h a l t i t u d e and in s e v e r e weather conditions. A belief common among climbers that descending is more risky than ascending is not supported by these data, which show that 69% of injuries occurred during ascending. If one considers, however, that the descent usually takes a fraction of the time required for the ascent, risk of injury per hour exposed m a y in fact be greater while descending. Relatively Annals of Emergency Medicine
few injuries were reported to have been caused by failure of climbing safety e q u i p m e n t , a finding supported by other studies in w h i c h equipment failure was blamed for 4% to 8% of injuries.5, 6 These NPS data have several limitations and should be interpreted with caution. First , the high casefatality ratio of 28% is similar to that of other studies based on rescue reports or hospital records.6, 7 The data from such studies are not representative of all climbing-related injuries because only the most severe injuries and deaths are usually reported. In comparison, case-fatality ratios of 5% to 9% h a v e been reported in studies based on the more inclusive data of surveys, clinic records, or i n s u r a n c e c l a i m s . S,S,9 S e c o n d , climbing-related injuries during 1981 through 1982 may not b e representative of injuries in the national parks in other years: Third, we were unable to calculate r a t e s of injury because the actual number of climbers in the national parks is unknown. The AAC figure of 100,000 climbers is a rough estimate, but this includes climbing outside the national parks. Climbers in most parks are not required to register; such a requirement may improve estimates of climbers at risk but could be impractical or difficult to enforce in certain areas. Finally, injuries may not have been detected or reported uniformly among the different parks or regions; the apparent variation in rates of injury probably reflects different reporting practices as well as differences in actual risk of injury. Despite these limitations, the NPS Safety and O c c u p a t i o n a l H e a l t h M a n a g e m e n t I n f o r m a t i o n System may be of potential use as a surveillance system for severe climbingrelated injuries in the national parks, a source of complementary injury data for the AAC, and a stimulus for additional studies in specific parks Or climbing areas. Because of the details reported for most cases, the NPS data may also be helpful in understanding the circumstances and prevention of injury. Ongoing injury surveillance data provided by the AAC or NPS are im977/127
CLIMBING INJURIES Addiss & Baker
p o r t a n t for additional descriptive studies and for evaluating the impact of preventive strategies. However, as noted by Haddon 1° for other sports, developing effective strategies to prevent climbing-related injuries will r e q u i r e f u r t h e r u n d e r s t a n d i n g of climbers and their exposure to risk, the environment in which the spor t takes place, and the rules and nature of the sport itself. P r e v e n t i o n of climbing-related injuries has become an increasingly important issue for climbers, NPS officials, and emergency physicians. How best to preserve the essence of climbing while preventing injuries is a matter of considerable debate, especially in view of pending litigation against equipment manufacturers and professional mountain guides, n The unique characteristics of climbing as a sport and the role and limitations of traditional mountaineeri.ng safety measures in preventing climbing-related injury are explored in the following discussion.
PREVENTION OF MOUNTAIN CLIMBING INJURIES: A CLOSER LOOK Injury prevention in the mountain environment is inhibited by several unique factors. Physical isolation, severe weather conditions, and lack of a v a i l a b l e t r a n s p o r t to e m e r g e n c y medical facilities have been cited as increasing the morbidity and mortality associated w i t h climbing injuries. 9 Equally important, however, as noted by Haddon, m is the nature of the sport itself, which is inextricably bound with risk. Three basic characteristics of the sport - risk, performance, and demand should be considered in any prevention program aimed at reducing climbing-related injuries. These characteristics are described in a new model. The basic model, adapted from Blumenthal, 1~ is comprised of two curves: one representing the difficulty or demands of the climb and the other representing the climber's performance, both of which vary over time. A fall or other "accident" occurs when the demands of a particular task exceed the capabilities of human performance and the two curves intersect (Figure 21. Prevention of injury is possible by either reducing the demands of the climb or improving climber performance. Task demands for rock climbing 128/978
TABLE. Cause of mountain climbing injuries, National Park Service Accident Reporting System, 1981 - 1982
Cause of Injury
Fatal Injuries N % of Total
Falls, total Unspecified Loss of footing Anchor failure Into crevasse Fatigue or handhold failure Avalanche or icefall Frostbite Hit by falling rock High-altitude cerebral edema Other, unknown Total
24 12 8 2 1 1 10 0 1 0 1 36
have been quantified in the widely used Yosemite decimal system, which rates the difficulty of a climb f r o m r e l a t i v e l y e a s y {5.0) to ext r e m e l y difficult (5.14). C l i m b e r s c o m m o n l y measure their climbing ability by this scale. Other types of climbing, such as vertical ice, are similarly rated. For a given climb, the model can describe the interplay of factors affecting the demand of the climb and the performance of the climber (Figure 3). The d e m a n d curve, determ i n e d p r i m a r i l y by the Yosemite decimal rating, is increased at high altitude or under poor weather or surface conditions. T h e p e r f o r m a n c e curve is determined by the climber's ability and judgment and is decreased by factors such as dehydration, hypothermia, suboptimal acclimatization, poor physical conditioning, inadequate equipment, fatigue, or altered mental status. An additional curve is included in the new model that describes the probability of severe injury when the performance and demand curves intersect (Figure 3). This curve is dependent on the specific injury event. If the event is a fall, for example, the probability of severe injury will increase with the distance fallen before impact (a function of distance from the ground or above the last piece of protection}, the hardness of the landing s u r f a c e , and i m p r o p e r ropehandling technique on the part of Annals of Emergency Medicine
66
28 0 3 0 3 100
Nonfatal Injuries N % of Total 71 31 33 2 1 4 1 6 3 3 7 91
78
1 7 3 3 8 100
one's climbing partner. Part of the a t t r a c t i o n of mountaineering and other high-risk recreational activities is the occasional near-intersection of demand and performance curves. The risk of potentially severe injury, represented by the third curve, may play a peculiar role in m o t i v a t i n g some climbers. R a t h e r t h a n f o c u s i n g d i r e c t l y on these underlying elements of risk, demand, and performance, mountaineering safety programs have traditionally e m p h a s i z e d three m a i n principles: proper equipment, adequate experience and training, and good judgment. 13 Reducing task demands through engineering and safe equipment design has proved to be a particularly effective passive strategy in preventing injuries. ~4 Passive or automatic protection, such as canoe flotation, requires no effort on the part of the individual using the equipment. Unlike active strategies, which depend on individual behavior (eg, wearing a climbing helmetl, many passive measures focus on reducing t a s k demands. Yet some human endeavors, including climbing, are appealing precisely because they are challenging Itask demands are highl. In contrast to the success of safe product design in preventing injuries in the home and workplace, the introduction of m o d e m climbing equipment, designed for efficiency and safety, has been accompanied by a sharp escala18:9 September 1989
ti0n of climbing standards. R a t h e r than decreasing, d e m a n d s have increased dramatically to parallel the high performance made possible, i n part, by better equipment. Some passive strategies focus on reducing the probability of severe iniury when a fall or other injury event occurs ( r e p r e s e n t e d by t h e t h i r d curve in the m o d e l ) . T h e u s e of automatic-release ski bindings is an example of effective a p p l i c a t i o n of such a strategy. M a n y t r a d i t i o n a l safety m e a s u r e s r e c o m m e n d e d for mountaineers w o u l d r e d u c e i n j u r y severity, but m o s t of these require deliberate action on the part of the individual climber. Proper p l a c e m e n t of protection to reduce the distance of a potential fall, for example, requires both experience and careful attention. Some of t h e s i m p l e s t of these safety measures, such as wearing a chest harness or safety h e l m e t (requiring only infrequent action), are often rejected as unnecessary or bothersome. If advances in c l i m b i n g e q u i p m e n t have neither decreased demands nor diminished risk, w h a t t h e n of the two other m e m b e r s of the " s a f e t y triad": adequate t r a i n i n g and good judgment? Do t r a i n i n g a n d experience decrease m o u n t a i n e e r i n g risk or merely i n c r e a s e c o n f i d e n c e w h i l e risk remains c o n s t a n t - or even increases? There is some evidence to support the n o t i o n t h a t r i s k of i n j u r y is higher among inexperienced or inadequately trained climbers. Investigators have found high proportions of injured c l i m b e r s l a c k i n g e x p e r i ence,2,6,8 but the level of experience for comparable u n i n j u r e d climbers is unknown. Oberli, using n a t i o n a l insurance data from Switzerland, estimates the risk of c l i m b i n g - r e l a t e d death among m e m b e r s of the Swiss Alpine Club to be one t e n t h that of nonmembers, w h o p r e s u m a b l y are less experienced. 9 Injuries associated with d o w n h i l l s k i i n g , a n a c t i v i t y similar in some respects to m o u n taineering, have been shown to be inversely correlated w i t h skiing ability and experience. 1>17 Risk of fatal injury,~ on the other hand, may increase wi~h experience. In a study by Tongue, 18 hang glider
pilots w i t h m o r e t h a n 200 flights Were overrepresented a m o n g the fatalities. As the hang glider pilot gains experience, he a t t e m p t s more difficult maneuvers in more marginal conditions, ~9 a progression n o t unlike that of the m o u n t a i n e e r . Those w h o c l i m b i n t h e H i m a l a y a s are among the most experienced and skillful mountaineers, yet the Himalayan climbing m o r t a l i t y rate is probably the highest i n the world. 20 In potential high-risk sports, as the t a s k - d e m a n d curve approaches the p e r f o r m a n c e c u r v e , j u d g m e n t becomes the crucial m e m b e r of the trad i t i o n a l safety triad. Impaired judgm e n t or climber error was associated w i t h 39% to 50% of climber injuries i n t h r e e r e c e n t studies.S,6, 9 G o o d j u d g m e n t is elusive, n o t ensured by technical training or experience; it is hard to learn and harder to teach. As the popularity of c l i m b i n g cont i n u e s to grow, t r a d i t i o n a l safety principles alone m a y n o t be adequate to p r e v e n t the o c c u r r e n c e of additional injuries. The u n d e r l y i n g elem e n t s and nature of the sport m u s t also be considered. Models, such as the one we present, can be used to evaluate specific climbs or c l i m b i n g areas. Clusters of injuries at a certain point in a climb m a y represent, for example, underrating of that part of the climb. Models m a y also facilitate analysis of factors specific to certain areas that elevate task d e m a n d s or d e c r e a s e c l i m b e r p e r f o r m a n c e . Inc l e m e n t weather, for i n s t a n c e , has played an i m p o r t a n t role i n recent fatalities i n Yosemite, where it is often unanticipated. CONCLUSION Several groups, i n c l u d i n g physicians, search and rescue teams, park officials, and climbers, are currently i n t e r e s t e d i n t h e p r e v e n t i o n of c l i m b i n g - r e l a t e d i n j u r y a n d death. There is a need for i m p r o v e d data, more sensitive models, and thoughtful application of p r e v e n t i v e strategies t h a t d e c r e a s e m o r b i d i t y a n d m o r t a l i t y w i t h o u t v i o l a t i n g the nature of m o u n t a i n e e r i n g . Such strategies developed for m o u n t a i n e e r i n g m a y have additional application to o t h e r p o t e n t i a l l y h i g h - r i s k recreational activities.
The authors thank Kay L Doerr, Safety Specialist, and Stanley T Albright, Associate Director, Park Operations, of the National Park Service, Washington, DC, for their generous assistance in providing the NPS data. REFERENCES 1. Williamson JE (ed}: Accidents in North American Mountaineering •979. New York, The American Alpine Club, 1979. 2. Williamson JE (ed): Accidents in North American Mountaineering 1985. New York, The AmericanAlpine Club, 1985. 3. De Haven H: Mechanicalanalysisof survival in falls from heights of fifty to one hundred and fifty feet. War Med 1942;2:586496. 4. Snyder RG: Man's survivability of extreme forces in free-fall impact, in AGARD Conference ProceedingsNo. 88 on LinearAcceleration of Impact Type. 1971;5.1-5.13 (AGARDCP-88-71). 5. McClennanJG, UngersmaJ: Mountaineering accidents in the Sierra Nevada. Am J Sports Med 1983;Ih160-163. 6. SchussmanLC, Lutz LJ: Mountaineeringand rock-climbing accidents. Phys Sports Med 1982;10:53761. 7. Foray J, Herry JP, Vallet JH, et ah Les accidents de montagne. Chirurgie 1982~108:724-733. 8. Wilson R, Mills WJ Jr, Rogers DR, et al: Death on Denali. West J Med 1978;128:471-476. 9. Oberli H: Der bergunfall, alpines rettungswesen. Z Unfallmed Berufskr 1981;74:3-9. 10. Haddon W Jr: Principlesin research on the effects of sports on health. JAMA 1966;197: 163-166. 11. KennedyM: Moneytalks, nobodywalks (editorial). Climbing 1989;114:6. 12. Blumenthal M, cited in Baker SP: Injury control, in Sartwell PE (ed): Preventive Medicine and Public Health, ed 10. New York, Appleton-Century-Crofts,1973, p 987-1005. 13. Ferris BG: Mountain-climbing safety. iV Engl J Med 1963;268:662-664. 14. Haddon W Jr: Strategy in preventive medicine: Passive vs. active approaches to reducing human wastage. J Trauma 1974;14:353-354. 15. HaddonW Jr, EllisonAE, Carroll RE: Skiing injuries: Epidemiologic study. Public Health Rep 196%77:975~985. 16. Young LR, Oman CM, Crane H, et al: The etiology of ski injuries: An eight year study of the skier and his equipment. Orthop Clin North Am 1976;7:13-29. 17. Criqui MH: The epidemiologyof skiing in~ juries. Minn Med 1977;60:877-880. 18. TongueJR: Hang glidinginjuries in California. l Trauma 1977;17:898-902. 19. KrissoffWB, EisemanB: Injuries associated with hang gliding.JAMA 1975;233:158-160. 20. Koerner M: Risks of climbing. American Alpine News I984;5:8~9.
See related editorial, p 1012 18:9September 1989
Annals of Emergency Medicine
979/129