Objective.—Dizziness is a symptom of acute mountain sickness (AMS). This study tested whether immediate fall in systolic blood pressure (BP) on standing was more severe at altitude and whether this was associated with symptoms of dizziness.

Methods.—Eighty-five lowlanders flew into La Paz, Bolivia (3650 m), and after 4 to 5 days of acclimatization ascended in 90 minutes to the Chacaltaya Laboratory (5200 m) by road. Blood pressure was measured on 5 occasions, 3 times at 5200 m and twice at sea level, before and after the expedition using a mercury sphygmomanometer. Both a supine and an erect (within 15 seconds of standing) BP measurement were recorded. Participants recorded whether they felt dizzy on standing. A mixed-effect model was used to test for a difference in the change in BP for time and altitude.

Results.—The immediate fall in systolic BP observed on standing was significantly greater (P < .001) on all 3 altitude study days (18.2, 23.4, and 20.7 mm Hg) than at sea level (12.2 and 12.4 mm Hg). There was no significant difference in the change in diastolic BP or change in mean arterial BP between sea level and altitude.

Conclusions.—The immediate drop in systolic BP observed on standing was greater at altitude. However, mean arterial pressure was maintained, and we found no association between the degree of immediate fall in BP and dizziness or AMS.

Objective.—Although hypothermia is preventable, little has been published on its epidemiology. This study estimates the incidence of hypothermia and other cold-related morbidity emergency department (ED) visits in the United States.

Methods.—We identified hypothermia and other cold-related morbidity ED visits from the 1995– 2004 National Hospital Ambulatory Medical Care Surveys using the International Classification of Diseases, Ninth Revision (991.6–991.9) or cause-of-injury E-codes (901.0–901.9 and 988.3).

Results.—In the United States there were an estimated 15 574 (95% CI = 9 103–22 045) hypothermia and other cold-related morbidity ED visits during 1995 to 2004. Compared with other ED patients, those with hypothermia and other cold-related morbidity diagnoses were older (mean age 45 vs 36 years; P = .009) and were more likely to be uninsured (risk ratio [RR] = 2.44; 95% CI = 1.54–3.84). Hypothermia and other cold-related morbidity ED visits required more transfers to critical care units (RR = 6.73; 95% CI = 1.8–25.0) than did other ED visits.

Conclusions.—Hypothermia and other cold-related morbidity is a preventable resource-intensive condition that tends to affect the disadvantaged.

Objective.—It is well established that a combination of factors, including ethnicity, may influence an individual's response to cold stress. Previous work from our laboratory has demonstrated that when faced with a cold challenge, there is a similar response in heat production between Caucasian (CAU) and African American (AA) individuals that is accompanied by a differential response in core temperature. The objective of this study was to evaluate the influence of ethnicity (CAU vs AA) on the thermoregulatory response after acute cold exposure (ACE-REC, 25°C air).

Methods.—Five AA males (20.8 ± 0.5 years) and 10 CAU males (25.6±4.9 years) underwent pre-experimental testing to determine Vo_2max (AA = 37.2 ± 0.1 mL·kg⁻¹·min⁻¹, CAU = 44.3 ± 8.7 mL·kg⁻¹·min⁻¹) and body composition (AA = 14.6 ± 5.4%, CAU = 19.2 ± 5.0%). Participants underwent acute cold exposure that consisted of 120 minutes of exposure to 10°C air (ACE) followed by 120 minutes of recovery in 25°C air (ACE-REC). Rectal temperature (T_re) was measured via a rectal thermistor. Mean skin temperature (T_sk) was assessed with thermistors. Oxygen consumption (Vo₂) was assessed via indirect open circuit spirometry. Rectal temperature and T_sk were measured continuously, and if T_re ≤ 35°C, testing was terminated.

Results.—Analysis of variance for ACE-REC revealed a significant main effect for T_sk across time (P < .001), T_re across time (P < .001), and Vo₂ across time (P < .001). In addition, a significant time × ethnicity interaction was revealed for T_re (P = .008), T_sk (P = .042), and Vo₂ (P = .019) during ACE-REC.

Conclusions.—Based on these data, there is a differential response between CAU and AA across time for Vo₂, T_re, and T_sk ACE-REC.

Objective.—To describe the epidemiology of mountain incidents and mountain rescue operations occurring in Banff, Yoho, and Kootenay National Parks between 1 January 2003 and 31 December 2006.

Methods.—Retrospective review of Banff, Yoho, and Kootenay Public Safety Occurrence Reports detailing rescue operations within the study period. Demographics, activity, reason for rescue, mode of rescue, type of injury, and fatalities were analyzed.

Results.—A total of 317 emergency mountain rescue operations involving 406 persons was documented. The mean age of the rescued population was 35.2 years, and this population was predominantly male (63.1%). Hikers were involved in 43.5% of incidents, and ‘slips and falls’ were responsible for 50.2%. Helicopter was the mode of rescue in 64% of cases. Almost half (40.7%) of all rescues involved people with no injuries. The limbs were the most common body part affected (68% of traumatic injuries). Forty fatalities occurred—45% due to avalanches and 27.5% due to slips and falls.

Conclusions.—This study offers a synopsis of the rescue service provided by Parks Canada Rescue in the study area. Further work is needed to separate primary and contributory causes of mountain incidents, and this can be achieved by use of better data collection methods. Hospital follow-up is required to accurately assess the morbidity and mortality associated with mountain incidents. Data presented are expected to be of value to a variety of tourism, health, and safety organizations.

Objective.—The study aimed to examine the physiological responses to acute normobaric hypoxia during an intermittent walking protocol.

Methods.—Twelve active healthy male participants completed a 125-minute test that involved rest and walking (50% V̇o_2max) during normoxic (20.93%O₂) and 2 hypoxic conditions (14%O₂ and 12%O₂). A range of physiological markers were measured throughout the test. Lake Louise Questionnaire scores and Environmental Symptoms Questionnaire cerebral scores were used as a measurement of acute mountain sickness symptoms.

Results.—Oxygen saturation, thermal sensation scale, heart rate, perceived thirst, core temperature, rating of perceived exertion, feeling state, and Δbody mass all positively correlated with the highest Lake Louise Questionnaire and Environmental Symptoms Questionnaire cerebral scores (P < .05) and were significantly different between the 3 conditions during the exercise phases.

Conclusion.—A range of physiological markers are associated with symptoms of acute mountain sickness following brief periods of hypoxic exposure.

Objectives.—Cold water temperature is a significant factor in North American drownings. These deaths are usually attributed to hypothermia. Survey questions were administered to 661 attendees of cold-stress seminars—including medical, rescue, law enforcement and lay attendees—to determine general knowledge of the effects of ice water immersion and responses to 2 public service educational slogans.

Methods.—Five questions were posed at the beginning of seminars to 8 groups (ranging in size from 46 to 195) during a 2-year period. Π² analyses were used to determine if responses within any occupational category differed from the group responses.

Results.—A high portion of respondents greatly underestimated the time to become hypothermic in ice water (correct answer >30 minutes; 84% stated 15 minutes or less) and the time until cooling was life threatening (correct answer >60 minutes; 85% stated 30 minutes or less). There were no occupational differences in these responses. Most of the respondents identified a correct cause of death during cold stress (81% stated cardiac arrest, hypothermia, or drowning). Although both educational slogans had some advantages, between 40% (Slogan #1) to 50% (Slogan #2) of respondents did not respond correctly.

Conclusions.—The majority of respondents underestimated the time available for survival during ice water immersion. It is important to educate the public accurately to decrease the probability of panic under these circumstances. More work is required to develop effective educational slogans that provide proper information and actions for victims of cold-water immersion.

Objective.—The purpose of this study was to determine the impact of a nationally developed snakebite treatment protocol on the amount of anti snake venom (ASV) used in treating snakebites in a developing country and its effect on mortality. In addition, basic epidemiology data were collected and analyzed.

Methods.—Experts in Indian snakebites developed a protocol specifically designed for snakebite treatment in India. A training program was implemented in Midnapore Medical College in West Bengal, India, under the direction of the Health Minister to train care providers in the new protocol. After training, data were collected for 839 snakebite victims over a 12-month period and included epidemiological data, ASV volumes administered, and mortality. The results were collated and compared with results calculated from 780 snakebite victims treated during the 12-month period before implementation of the protocol. Treatment prior to protocol implementation was based on knowledge gained by the care providers from western and forensic medicine textbooks.

Results.—Protocol-guided treatment resulted in a 66% decline in the amount of ASV administered to victims. Fewer victims received ASV based on rational guidelines for assessing envenomation, dosage and repeat dosage, and clear endpoints to ASV therapy. In addition, there was a trend towards reduced mortality and an absolute reduction of 24%.

Conclusion.—Use of the protocol reduced ASV utilization and the number of deaths. Locally developed protocols should be encouraged by such organizations as the World Health Organization and national and state governments and should be established with significant input from local experts.

The crown-of-thorns starfish (Acanthaster planci) inhabits coral reefs, largely throughout the Indo-Pacific region. Its dorsal surface is covered with stout thorn-like spines. When handled or stepped on by humans, the spines can puncture the skin, causing an immediate painful reaction, followed by inflammation and possible infection. Initial pain and swelling may last for days. Effects of envenomation on the liver have been demonstrated previously in animal models, but hepatic toxicity has not previously been described in humans. We describe elevated liver enzymes in a 19-year-old female associated with A planci spine puncture wounds. To our knowledge, this is the first documented report of transaminitis in a human after A planci envenomation.

Borrelia hermsii causes tick-borne relapsing fever (TBRF) in the Pacific Northwest. There are few reports of TBRF-associated acute respiratory distress syndrome. One such unusually severe case is described. Literature is reviewed including diagnosis, treatment, and prevention.

Objective.—Our objective was to determine the incidence of acute mountain sickness (AMS) and the cardiorespiratory responses, in children and their parents, after rapid ascent to 3500 m. The sample population was composed of children and their parents who ascended within 24 hours from Arica (sea level) to Putre (3500 m) in Chile.

Methods.—Acute mountain sickness symptoms were evaluated using the Children's Lake Louise Score (CLLS) in children and the Lake Louise Scoring System in their parents. Heart rate, pulse oximetry, and AMS symptoms were evaluated in Arica before ascent, in Putre, and on return to Arica.

Results.—The mean CLLS was 10.8 ± 3 at Putre, with 92% of children developing AMS. Low oxygen saturation (80% ± 2%) and tachycardia (129 ± 9 beats/min) were observed in children with higher AMS scores. In contrast, parents had higher oxygen saturation (89% ± 3%), less tachycardia (87 ± 13 beats/min), and a 25% incidence of AMS.

Conclusions.—Our results indicate that children exposed acutely to high altitude are more sensitive to hypobaric hypoxia than are their parents, as manifested by symptoms of AMS, significant oxyhemoglobin desaturation, and tachycardia. Young children may experience an exaggerated hypoxemic response to high altitude exposure, and young age may be an additional risk factor for the development of AMS.

High-altitude pulmonary edema (HAPE) is a life-threatening noncardiogenic form of pulmonary edema (PE) that afflicts susceptible persons after rapid ascent to high altitude above 2500 m. Its pathogenesis is related to increased sympathetic tone, exaggerated hypoxic pulmonary vasoconstriction, uneven hypoxic pulmonary vasoconstriction with overperfusion of some regions of the pulmonary vascular bed, increased pulmonary capillary pressure, stress failure of pulmonary capillaries, and alveolar fluid leak across capillary endothelium resulting in interstitial and alveolar edema. Prevention of HAPE is most effectively achieved by gradual ascent with time for acclimatization, although recent small studies have highlighted a number of pharmacologic options. Inhaled salmeterol prevents HAPE presumably by increasing alveolar fluid clearance, the phosphodiesterase-5 inhibitor tadalafil works by acting as a pulmonary vasodilator, and dexamethasone seems to prevent HAPE by stabilizing the capillary endothelium, along with other potential effects. These investigations have yet to be validated in widespread clinical practice. Nifedipine, which prevents HAPE via its effects as a pulmonary vasodilator, has a longer history of clinical use. The most effective and reliable treatment of established HAPE is immediate descent and/or adequate flow supplemental oxygen to maintain arterial saturation above 90%, accompanied by rest from strenuous physical activity. Use of a portable hyperbaric chamber is an effective temporizing measure, and nifedipine may be used for treatment of HAPE, although only as an adjunct to descent and/or supplemental oxygen if these methods of treatment are not immediately available to a person with HAPE.