Abstract
Editorial: 100th Anniversary of the Anglo-American Pikes Peak Expedition
One of the most famous early scientific expeditions to high altitude took place just 100 years ago. Douglas, Haldane, Henderson, and Schneider spent 5 weeks on the summit of Pikes Peak, and their findings make good reading even today. A colorful collaborator was Mabel FitzGerald who did not accompany the men on the summit but traveled alone, accompanied only by a mule, visiting the mining camps of Colorado where she measured alveolar gas partial pressures that are still cited.
Prehospital resuscitation of the buried avalanche victim
Brugger and colleagues (p. 199) reviews the current state of the art for treating avalanche victims.
Scientific Articles
Sildenafil citrate for the prevention of high altitude hypoxic pulmonary hypertension: Double blind, randomized, placebo-controlled trial
Bates and colleagues (p. 207) point out that pulmonary hypertension is an important factor in the development of high altitude pulmonary edema. Because sildenafil is a pulmonary vasodilator, there is interest in whether this medication might have a place in prevention. Sixty-two lowlanders flew to La Paz, Bolivia, and then ascended to 5200 m, where the effects of sildenafil on pulmonary artery systolic pressure were studied. There was no significant difference between the pressures of the treated group and a placebo group and there was no difference in the prevalence of AMS.
Sildenafil has little influence on cardiovascular hemodynamics or 6-km time trial performance in trained men and women at simulated high altitude
Jacobs and co-workers (p. 215) tested whether the reduction in pulmonary arterial pressure resulting from sildenafil improved exercise performance at a simulated altitude of approximately 3500 m in a low-pressure chamber. There were some differences between subjects, but in general sildenafil had little influence on cardiovascular hemodynamics, arterial oxygen saturation, or exercise performance.
D-dimer is not elevated in asymptomatic high altitude climbers after descent to 5340 meters: The Mount Everest Deep Venous Thrombosis Study (Ev-DVT)
Thromboembolism is a potential danger at high altitude and in this study Zafren and colleagues (p. 223) determined the prevalence of D-dimer, a marker for deep venous thrombosis at the Everest Base Camp, altitude 5340 m. In none of the 76 high altitude climbers was the test positive, suggesting that there is a low prevalence of deep venous thrombosis in asymptomatic climbers.
High altitude sleep disturbances monitored by actigraphy and polysomnography
It is well known that lowlanders ascending to high altitude frequently have sleep disturbances, including periodic breathing. In this study, Nussbaumer-Ochsner and collaborators (p. 229) studied 14 subjects at an altitude of 4559 m using a combination of actigraphy (device to measure movement) and polysomnography. It was found that actigraphy, which is a relatively simple test, accurately estimates sleep efficiency and duration.
Poor sleep quality predicts decreased cognitive function independently of CMS score in young soldiers with polycythemia stationed in Tibet
It is known that when lowlanders ascend to high altitude they have impaired sleep and also impaired cognitive function, though the relation between the two is not clear. Kong and colleagues (p. 237) studied 230 soldiers stationed at altitudes between 3658 and 3996 m. Impaired sleep was more likely in subjects with polycythemia and this group also had a significantly lower score for cognitive function, especially verbal short term memory.
Intermittent hypoxia mobilizes hematopoietic progenitors and augments cellular and humoral elements of innate immunity in adult men
Intermittent hypoxia is known to alter many features of normal physiology, and in this study Serebrovskaya and colleagues (p. 243) studied its effect on cellular and humoral elements of innate immunity. In a total of 15 subjects, they reported that intermittent hypoxia enhances innate immunity by mobilizing hematopoietic stem and progenitor cells, activating neutrophils, and increasing circulating complement and immunoglobulins.
Preservation of serotonin-mediated contractility in adult sheep pulmonary arteries following long-term, high-altitude hypoxia
Papamatheakis and colleagues (p. 253) studied features of hypoxic pulmonary vasoconstriction in adult sheep exposed to an altitude of 3801 m for over 100 days. It was found that there was no increase in arterial medial wall thickness, but aspects of calcium-dependent contraction were altered.
Brief Reports
Intravenous iron supplementation may protect against acute mountain sickness: A randomized, double-blinded, placebo-controlled trial
Robbins et al. (p. 265) reasoned that as iron influences cellular oxygen pathways, iron supplementation may reduce the incidence of AMS. This study suggests that this may be true.
Freezing and frostbite on Mount Everest: New insights into wind chill and freezing times at extreme altitude
Cold injury is common at extreme altitudes. In this study, Moore and Semple (p. 271) used meteorological data sets to determine factors related to wind chill and facial frostbite time. They suggest that barometric pressure is a useful predictor of cold injury that is often associated with storms.
Historical Article
Mountain Research and Rescue on Denali: A Short History from the 1980s to Present Day
Rodway and collaborators (p. 277) note that over 1000 climbers have attempted to reach the summit of Mt. McKinley (altitude 6194 m) every climbing season for the last 20 years. They describe how the National Park Service and a seasonal high altitude camp established in 1982 have reduced the morbidity and mortality on the mountain.
Meeting Report
Hypoxia 2011
Anholm and Foster (p. 285) describe the highly successful meeting held in Lake Louise in February 2011. This is one of a continuing series that is a landmark in high altitude medicine.
Letter To The Editor
UIAA/ICAR/ISMM Diploma of Mountain Medicine
Hillebrandt (p. 291) describes a new course that combines medical and mountaineering skills to be developed in Nepal.