scholarly journals The Effect of Ambient Temperature on the Use of Supplemental Oxygen at High Altitude

2008 ◽  
Vol 19 (2) ◽  
pp. 143-144
Author(s):  
Jeremy S. Windsor ◽  
James S. Milledge ◽  
George W. Rodway
Keyword(s):  
Ambient Temperature ◽  
High Altitude ◽  
Supplemental Oxygen

Acute hypoxia in a simulated high-altitude airdrop scenario due to oxygen system failure

2017 ◽  
Vol 123 (6) ◽  
pp. 1443-1450 ◽  
Author(s):  
William Ottestad ◽  
Tor Are Hansen ◽  
Gaurav Pradhan ◽  
Jan Stepanek ◽  
Lars Øivind Høiseth ◽  
...  
Keyword(s):  
High Altitude ◽  
Acute Hypoxia ◽  
Supplemental Oxygen ◽  
Cerebral Oximetry ◽  
Arterial Oxygen ◽  
Hypoxic Exposure ◽  
System Failure ◽  
Oxygen System ◽  
Simulated High Altitude ◽  
Oxygen Tensions

High-Altitude High Opening (HAHO) is a military operational procedure in which parachute jumps are performed at high altitude requiring supplemental oxygen, putting personnel at risk of acute hypoxia in the event of oxygen equipment failure. This study was initiated by the Norwegian Army to evaluate potential outcomes during failure of oxygen supply, and to explore physiology during acute severe hypobaric hypoxia. A simulated HAHO without supplemental oxygen was carried out in a hypobaric chamber with decompression to 30,000 ft (9,144 m) and then recompression to ground level with a descent rate of 1,000 ft/min (305 m/min). Nine subjects were studied. Repeated arterial blood gas samples were drawn throughout the entire hypoxic exposure. Additionally, pulse oximetry, cerebral oximetry, and hemodynamic variables were monitored. Desaturation evolved rapidly and the arterial oxygen tensions are among the lowest ever reported in volunteers during acute hypoxia. PaO2 decreased from baseline 18.4 (17.3–19.1) kPa, 138.0 (133.5–143.3) mmHg, to a minimum value of 3.3 (2.9–3.7) kPa, 24.8 (21.6–27.8) mmHg, after 180 (60–210) s, [median (range)], N = 9. Hyperventilation with ensuing hypocapnia was associated with both increased arterial oxygen saturation and cerebral oximetry values, and potentially improved tolerance to severe hypoxia. One subject had a sharp drop in heart rate and cardiac index and lost consciousness 4 min into the hypoxic exposure. A simulated high-altitude airdrop scenario without supplemental oxygen results in extreme hypoxemia and may result in loss of consciousness in some individuals. NEW & NOTEWORTHY This is the first study to investigate physiology and clinical outcome of oxygen system failure in a simulated HAHO scenario. The acquired knowledge is of great value to make valid risk-benefit analyses during HAHO training or operations. The arterial oxygen tensions reported in this hypobaric chamber study are among the lowest ever reported during acute hypoxia.

scholarly journals High-altitude Pulmonary Edema in Emergency Department: A Review

2021 ◽  
pp. 113-118
Author(s):  
Hisham Mohammed Sonbul ◽  
Abdu Saleh Alwadani ◽  
Bader Aziz Alharbi ◽  
D. Almaymuni, Saleh Mohammed ◽  
Abdulrazaq Abdulmohsen Alkhalaf ◽  
...  
Keyword(s):  
Pulmonary Edema ◽  
High Altitude ◽  
Supplemental Oxygen ◽  
Severe Form ◽  
Physical Effort ◽  
Disease Etiology ◽  
Salt Consumption ◽  
Pulmonary Vasodilator ◽  
High Altitude Pulmonary Edema ◽  
High Altitude Disease

High altitude pulmonary Edema (HAPE) is a severe form of high-altitude disease that, if left untreated, can result in death in up to half of those who are affected. Lowlanders who rapidly go to elevations more than 2500-3000 m are more likely to develop high altitude pulmonary Edema (HAPE). Individual sensitivity owing to a low hypoxic ventilatory response (HVR), quick pace of climb, male sex, usage of sleep medicine, high salt consumption, chilly ambient temperature, and intense physical effort are all risk factors. HAPE may be totally and quickly reversed if caught early and correctly treated. Slow climb is the most effective technique of prevention. A fall of at least 1000 meters, is the best and most certain treatment choice in HAPE. Supplemental oxygen, portable hyperbaric chambers, and pulmonary vasodilator medications (nifedipine and phosphodiesterase-5 inhibitors) may be beneficial. In this article we’ll be looking at the disease etiology, epidemiology, diagnosis and management.

scholarly journals Isolated psychosis during exposure to very high and extreme altitude – characterisation of a new medical entity

2017 ◽  
Vol 48 (11) ◽  
pp. 1872-1879 ◽  
Author(s):  
Katharina Hüfner ◽  
Hermann Brugger ◽  
Eva Kuster ◽  
Franziska Dünsser ◽  
Agnieszka E. Stawinoga ◽  
...  
Keyword(s):  
High Altitude ◽  
Acute Mountain Sickness ◽  
Supplemental Oxygen ◽  
Status Change ◽  
Statistical Manual ◽  
Medical Diagnoses ◽  
Diagnostic And Statistical Manual ◽  
Extreme Altitude ◽  
Medical Entity ◽  
Very High

BackgroundPsychotic episodes during exposure to very high or extreme altitude have been frequently reported in mountain literature, but not systematically analysed and acknowledged as a distinct clinical entity.MethodsEpisodes reported above 3500 m altitude with possible psychosis were collected from the lay literature and provide the basis for this observational study. Dimensional criteria of the Diagnostic and Statistical Manual of Mental Disorders were used for psychosis, and the Lake Louise Scoring criteria for acute mountain sickness and high-altitude cerebral oedema (HACE). Eighty-three of the episodes collected underwent a cluster analysis to identify similar groups. Ratings were done by two independent, trained researchers (κ values 0.6–1).FindingsCluster 1 included 51% (42/83) episodes without psychosis; cluster 2 22% (18/83) cases with psychosis, plus symptoms of HACE or mental status change from other origins; and cluster 3 28% (23/83) episodes with isolated psychosis. Possible risk factors of psychosis and associated somatic symptoms were analysed between the three clusters and revealed differences regarding the factors ‘starvation’ (χ2 test, p = 0.002), ‘frostbite’ (p = 0.024) and ‘supplemental oxygen’ (p = 0.046). Episodes with psychosis were reversible but associated with near accidents and accidents (p = 0.007, odds ratio 4.44).ConclusionsEpisodes of psychosis during exposure to high altitude are frequently reported, but have not been specifically examined or assigned to medical diagnoses. In addition to the risk of suffering from somatic mountain illnesses, climbers and workers at high altitude should be aware of the potential occurrence of psychotic episodes, the associated risks and respective coping strategies.

scholarly journals Cognitive function and mood at high altitude following acclimatization and use of supplemental oxygen and adaptive servoventilation sleep treatments

PLoS ONE ◽  
2019 ◽  
Vol 14 (6) ◽  
pp. e0217089 ◽  
Author(s):  
Erica C. Heinrich ◽  
Matea A. Djokic ◽  
Dillon Gilbertson ◽  
Pamela N. DeYoung ◽  
Naa-Oye Bosompra ◽  
...  
Keyword(s):  
Cognitive Function ◽  
High Altitude ◽  
Supplemental Oxygen ◽  
Adaptive Servoventilation

Effect of High Altitude Ambient Temperature on Crisping Quality of Potatoes in Kenya

1981 ◽  
Vol 47 (1-4) ◽  
pp. 38-42
Author(s):  
J. N. Kabira ◽  
P. Saint-Hilaire ◽  
M. J. R. Nout
Keyword(s):  
Ambient Temperature ◽  
High Altitude

scholarly journals Autonomic cardiovascular function in high-altitude Andean natives with chronic mountain sickness

2003 ◽  
Vol 94 (1) ◽  
pp. 213-219 ◽  
Author(s):  
C. Keyl ◽  
A. Schneider ◽  
A. Gamboa ◽  
L. Spicuzza ◽  
N. Casiraghi ◽  
...  
Keyword(s):  
Beneficial Effect ◽  
High Altitude ◽  
Baroreflex Sensitivity ◽  
Cardiovascular Function ◽  
Supplemental Oxygen ◽  
Arterial Oxygen ◽  
Control Group ◽  
Chronic Mountain Sickness ◽  
Mountain Sickness ◽  
Spontaneous Baroreflex

We evaluated autonomic cardiovascular regulation in subjects with polycythemia and chronic mountain sickness (CMS) and tested the hypothesis that an increase in arterial oxygen saturation has a beneficial effect on arterial baroreflex sensitivity in these subjects. Ten Andean natives with a Hct >65% and 10 natives with a Hct <60%, all living permanently at an altitude of 4,300 m, were included in the study. Cardiovascular autonomic regulation was evaluated by spectral analysis of hemodynamic parameters, while subjects breathed spontaneously or frequency controlled at 0.1 and 0.25 Hz, respectively. The recordings were repeated after a 1-h administration of supplemental oxygen and after frequency-controlled breathing at 6 breaths/min for 1 h, respectively. Subjects with Hct >65% showed an increased incidence of CMS compared with subjects with Hct <60%. Spontaneous baroreflex sensitivity was significantly lower in subjects with high Hct compared with the control group. The effects of supplemental oxygen or modification of the breathing pattern on autonomic function were as follows: 1) heart rate decreased significantly after both maneuvers in both groups, and 2) spontaneous baroreflex sensitivity increased significantly in subjects with high Hct and did not differ from subjects with low Hct. Temporary slow-frequency breathing may provide a beneficial effect on the autonomic cardiovascular function in high-altitude natives with CMS.

The growth of children at different altitudes in Ethiopia

1972 ◽  
Vol 264 (864) ◽  
pp. 403-437 ◽  
Keyword(s):  
Infectious Disease ◽  
Ambient Temperature ◽  
High Altitude ◽  
Sea Level ◽  
The Other ◽  
Skeletal Maturation ◽  
Early Puberty ◽  
Other Hand ◽  
The World ◽  
Different Altitudes

In this study were observed the effects of two widely differing environments on the growth and maturation of children from a presumed genetically homogeneous Ethiopian population. Major environmental differences included altitude above sea level, temperature, probably rainfall and humidity, together with the incidence of infectious disease. The results indicate that highland children, particularly boys, are taller, heavier and bigger in most physical dimensions than are lowland children. In both groups skeletal maturation is retarded (by American White standards) during later childhood; this retardation is more marked in lowlanders. In both groups, however, there is marked acceleration of skeletal maturation during early puberty. Haemoglobin values increase much more rapidly in highland children, but surprisingly, differences in chest dimensions are not particularly marked. It is concluded that hypoxia of the degree found in the high-altitude group (approximately 3000 m) is not sufficient to affect adversely the growth of children. On the other hand, the increased incidence of infectious disease in the ‘lowlands’ (approximately 1500 m) and possibly the raised ambient temperature, may restrict growth and maturation of children living in this environment. Thus, in contrast to the situation in other high-altitude parts of the world, the highlands in Ethiopia appear to be more favourable to growth than the lowlands.

scholarly journals Interactions Among Rumen Fermentation Characteristics, the Microbiota, and Host Gene Expression in Response to Ambient Temperature Fluctuations in Tibetan Sheep

2021 ◽  
Author(s):  
Weibing Lv ◽  
Xiu Liu ◽  
Yuzhu Sha ◽  
Hao Shi ◽  
Hong Wei ◽  
...  
Keyword(s):  
Gene Expression ◽  
Ambient Temperature ◽  
High Altitude ◽  
Rumen Fermentation ◽  
Host Gene ◽  
Tibet Plateau ◽  
Host Gene Expression ◽  
Microbial Composition ◽  
Fermentation Products ◽  
Tibetan Sheep

Abstract Background: As an important ruminant on the Qinghai-Tibet Plateau, Tibetan sheep can maintain their population reproduction rate in the harsh high-altitude environment of low temperature and low oxygen, which is related to their special adaptations to the plateau. Microbes (known as “second genomes”) play an important role in the host adaptations. However, there have been no reports on the effects of the interactions among rumen fermentation, the microbiota, and host gene expression on the adaptation of Tibetan sheep to high altitude.Results: Rumen fermentation characteristics, the microbiota, and rumen epithelial gene expression of Tibetan sheep in various months (February, April, June, August, October, and December) were analyzed. The results show that the rumen fermentation characteristics of Tibetan sheep differed in different months. The total SCFA, acetate, propionate, and butyrate concentrations were highest in Oct and lowest in Jun. The Cellulase (CL) activity was highest in Feb (when it was significantly higher than in Aug and Oct), while the acidic xylanase (ACX) activity was highest in Apr, followed by Jun (and it was significantly higher in both Apr and Jun than in Feb, Aug, and Oct). In addition, the diversity and abundance of rumen microbes differed in different months. Bacteroidetes (53.4%) and Firmicutes (27.4%) were the dominant phyla. Prevotella_1 and Rikenellaceae_RC9_gut_group were the dominant genera. The abundance of Prevotella_1 was highest in Jun (27.8%) and lowest in Dec (17.8%). Random forest analysis showed that Lachnospiraceae_NK3A20_group and Rikenellaceae_RC9_gut_group played important roles in rumen microbial composition in different months. In addition, the expression of CLAUDIN4 and ZO1 (ruminal epithelial barrier-related genes) was significantly higher in Apr than in Aug and Dec, while the expression of SGLT1 (nutrient absorption-related gene) was highest in Aug, but were significantly lower than CLAUDIN4 and ZO1 expression in the corresponding month. Correlation analysis showed that there were interactions among rumen fermentation characteristics.Conclusions: There was a certain correlation between rumen fermentation products, the microbiota, and host gene expression. The microbiota, and host gene expression, and the host adjusted the rumen fermentation and microbiota structure according to changes in ambient temperature, to adapt to the plateau environment.

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