Showing papers on "Altitude Hypoxia published in 2009"

Altitude hypoxia increases glucose uptake in human heart.

Abstract: Chen, Chi-Hsien, Yuh-Feng Liu, Shin-Da Lee, Wen-Chih Lee, Ying-Lan Tsai, Chien-Wen Hou, Chih-Yang Huang, and Chia-Hua Kuo. Altitude hypoxia increases glucose uptake in human heart. High Al...

Disequilibrium Between Alveolar and End-Pulmonary-Capillary O2 Tension in Altitude Hypoxia and Respiratory Disease: An Update of a Mathematical Model of Human Respiration at Altitude

Abstract: We have previously formulated and validated a mathematical model specifically designed to describe human respiratory behavior at altitude. In that model, we assumed equality of alveolar and end-pulmonary-capillary oxygen tensions. However, this equality may not hold true during rapid and prolonged changes to high altitudes producing severe hypoxia as can occur in aircraft cabin decompressions and in some respiratory diseases. We currently investigate this possibility by modifying our previous model to include the dynamics of oxygen exchange across the pulmonary capillary. The updated model was validated against limited experimental data on ventilation and gas tensions in various altitude-decompression scenarios. The updated model predicts that during rapid and sustained decompressions to high altitudes the disequilibrium of gas tensions between alveolar gas and capillary blood could be 10 Torr, or larger. Neglecting this effect underestimates the severity of a decompression and its potential to produce unconsciousness and subsequent brain damage. In light of these results, we also examined the effect of this disequilibrium on the diminished oxygen diffusion capacity that can occur in some respiratory diseases. We found that decreases in diffusion capacity which would have minimal effects at sea level produced significant disequilibrium of gas tensions and a large fall in hemoglobin oxygen saturation at a cabin altitude of 4000–8000 ft. As demonstrated, this new model could serve as an important tool to examine the important physiological consequences of decompression scenarios in aircraft and the pathophysiological situations in which the equilibrium of gas tensions along the pulmonary capillary are particularly critical.

Progress in researches for compound Danshen Dropping Pill in treating altitude hypoxia

Abstract: The anti-oxidative effects of compound Danshen Dropping Pill(DSP) have been widely studied in the aspects of traditional Chinese medicine,biochemical pharmacology,molecular pharmacology and clinical pharmacology.The adaptor-like effects of DSP have been gradually revealed,including its anti-hypoxia,anti-aging,anti-oxidative,anti-fatigue,anti-radiation and immunoregulation effects.Up-to-date it has been found that DSP attenuated histopathological damage in rats,regulated biochemical materials in blood,and improved cardiovascular responses,basic physiological indicators and hemorrheology in the high altitude acclimatization.DSP is applied in the treatments of plateau response,high altitude cerebral edema,chronic high altitude disease,plateau myocardial ischemia,plateau hyperviscosity syndrome and plateau acclimatization,as well as in health care,prevention,and rehabilitation.These effects of DSP need to be further verified by introducing evidence-based medicine.

Does high altitude increase risks of the elderly patients with coronary artery disease

Abstract: Corresponding author: Tian-Yi Wu, MD. State Key Laboratory of High Altitude Medicine, High Altitude Medical Research Institute, Nanchua West Road #344, Xining, Qinghai 810012, China. Tel:86971-6250870. E-mail: wutianyiqh@hotmail.com Objective To assess the effect of altitude hypoxia on the elderly patients with coronary artery disease (CAD). Methods Three subject groups were surveyed during their train trip on the highest railroad——the Qinghai-Tibet Railway: 22 elderly individuals with documented CAD, 20 healthy elderly controls, and 20 healthy young controls, all of whom from Beijing near the sea level (76 m). Survey questions addressed clinical features of their healthy conditions and aspects of their coronary disease. The baseline study was performed at Xining at an altitude of 2261m, and then during acute exposure to altitudes of 2808 m, 4768m, 5072 m and 4257 m by train for 24 hours. Resting pulse rate, blood pressure, oxygen saturation, electrocardiograph (ECG), and cardiac work estimated by the heart rateblood pressure double product were obtained five times in each subject at different altitudes. Results On arrival to altitudes between 4768 m and 5072 m, the older passengers, especially those with preexisting coronary disease, had higher HR, higher BP, and lower SaO 2 , as well as more frequent abnormalities on ECG, as compared to the younger healthy subjects. As compared with the healthy elderly controls, incomplete right bundle branch block, left ventricular hypertrophy, and ST segment depression were more frequently seen in the elderly coronary patients (P<0.01). Cardiac work in group 1 was increased by 13% 12 hours after arrival to altitudes between 2808 m and 5072 m. Oxygen saturation decreased significantly with the altitude increasing by train ascent but improved after inhalation of oxygen. Most of the older subjects tolerated their sojourn at high altitude well except one who developed angina repeatedly with a significant ST segment depression. Conclusions Coronary events and ECG signs of myocardial ischemia are rare in elderly individuals with CAD who travel from sea level to moderate altitudes of 1500m to 2800 m. Patients with CAD who are well compensated at sea level generally tolerate this moderate altitude well. However, it would be prudent for patients with CAD going to altitude above 3000 m. The patients should consult their physician before undertaking a trip to such altitude (J Geriatr Cardiol 2009; 6:137-141) .