Abstract
Editorial: Special topic: Central nervous system and high altitude (p. 97)
The Special Topic in this issue is the central nervous system at high altitude. This is an area of intense research. There are reviews of recent work on high altitude cerebral edema, intracranial pressure, cerebral blood flow, and cognitive function.
Sightings, Edited by Erik Swenson and Peter Bärtsch (p. 100)
Clinician's Corner, Edited by Andrew Luks
Pre-hospital core temperature measurement in accidental and therapeutic hypothermia
Strapazzon and colleagues (p. 104) emphasize that core temperature measurement is critical in the management of patients with hypothermia and this review discusses measurement techniques and how to tailor management using this information.
Special Topic: Central Nervous System and High Altitude
Update on high altitude cerebral edema including recent work on the eye
High altitude cerebral edema is a disease of great importance at high altitude and recent work on the retina and optic nerve shows promise of clarifying the pathology. Willmann and colleagues (p. 112) discuss the relative importance of a possible increase in capillary pressure on the one hand and the possible role of increased vascular permeability on the other.
Intracranial pressure at altitude
Wilson and colleagues (p. 123) review the controversial topic of intracranial pressure and its suggested role in high altitude headache, acute mountain sickness, and high altitude cerebral edema. The review discusses evidence for and against the importance of a rise in intracranial pressure.
Cerebral blood flow at high altitude
Ainslie and Subudhi (p. 133) review recent advances on this topic where most measurements are indirect and difficult to make. The role of arterial
Cognitive impairments at high altitudes and adaptation
Yan (p. 141) reviews the present state of knowledge on this important subject. While it is clear that lowlanders have reduced cognitive performance at high altitude, the issue for permanent residents is far from settled.
Other Scientific Articles
Vascular endothelial growth factor-A is associated with chronic mountain sickness in Andean population
Chronic mountain sickness is a common and debilitating disease especially among permanent residents of the South American Andes. Here Espinoza and colleagues (p. 146) describe work suggesting that a genetic change affecting Vascular Endothelial Growth Factor-A may be an important contributor to the disease.
Ischemic pre-conditioning improves oxygen saturation and attenuates hypoxic pulmonary vasoconstriction at high altitude
Ischemic pre-conditioning is a procedure carried out on an extremity that protects other organ systems from future injury. Foster and colleagues (p. 155) provide evidence that this intervention can reduce the fall in arterial oxygen saturation and limit the rise in pulmonary artery pressure following ascent to altitude.
Exercise capacity and selected physiological factors by ethnicity and residential altitude—cross-sectional studies of 9–10-year-old children in Tibet
This study by Bianba and colleagues (p. 162) compared exercise capacity and other physiological factors in a group of Tibetan children compared with Han Chinese at high altitude. The Tibetan children had a higher exercise capacity than Han Chinese. In addition Tibetan children at an altitude of 3700 m had a higher exercise capacity than children living at 4300 m.
Alterations in different indices of skeletal health after prolonged residency at high altitude
Basu and colleagues (p. 170) studied indices of bone health in sea level residents and those who spent from four months to a year at an altitude of 3450 m. A number of physical characteristics and biochemical markers were studied. It was concluded that the hypoxia associated with high altitude reduced bone strength as measured by indirect techniques, and altered various bone-related biochemical markers.
Anthropometric and body composition changes during expeditions at high altitude
Zaccagni and colleagues (p. 176) studied the physical adaptations of lowlanders in scientific expeditions to altitudes of 5050 m or 5300 m. Body height and mass, girth, and skinfold thickness were measured. Both sexes lost an average of 4% of body mass corresponding to 7.6 % of fat mass and 3.5% of fat free mass in males with the corresponding figures being 5.0% and 3.6% in females. The adaptations were faster in males than females. These changes occurred regardless of the amount of physical activity.
Acute effects of normobaric hypoxia on hand-temperature responses during and after local cold stress
Keramidas and coworkers (p. 183) looked at the effects of normobaric hypoxia on hand temperature responses as a result of a cold-water hand immersion. It was found that hypoxia did not aggravate the cold-induced fall in hand temperature but it did impair the re-warming response of the hand.
Effects of acute systematic hypoxia on human urinary metabolites using LC-MS based metabolomics
Lou and colleagues (p. 192) used liquid chromatography time-of-flight mass spectrometry to study metabolic responses during normobaric hypoxia. Over 1000 changes were seen and about 10% of these were significant. However there was great variability among the six subjects. One conclusion was an increase in purine metabolic products caused by the hypoxia.
Exposure to high altitude alters tear film osmolarity and breakup time
Eye problems caused by the dry air and cold temperatures at high altitude are common. This study by Willmann and colleagues (p. 203) at an altitude of 4559 m showed changes in tear film properties including an increased tear film osmolarity and a reduced tear film break-up time.
Letters to The Editor
Should sleep quality be part of the Lake Louise AMS score?
Milledge (p. 208) points out that many subjects at high altitude have poor sleep quality in the absence of acute mountain sickness (AMS). He supports the conclusion of MacInnis et al. in a previous issue of the Journal (14: 334–337, 2013) that the scoring of AMS should be changed.
Legionella pneumophila was isolated at high altitude in Tibetan plateau
Ryota and others (p. 209) found Legionella pneumophila, the culprit of Legionnaires' disease, in a number of samples of water at altitudes of 3000 to 4200 m in Qinghai Province, China. Apparently Legionella has not previously been reported at high altitude.