Tissue weights and adaptation response of the toad after 96 hours of exposure to simulated high altitude — A body fluid and hematological study

1985 ◽  
Vol 29 (4) ◽  
pp. 347-352 ◽  
Author(s):  
H. M. Biswas ◽  
M. C. Boral
Keyword(s):  
High Altitude ◽  
Body Fluid ◽  
Simulated High Altitude ◽  
Adaptation Response

Body fluid and hematologic changes in the toad exposed to 48 h of simulated high altitude

1981 ◽  
Vol 51 (4) ◽  
pp. 794-797 ◽  
Author(s):  
H. M. Biswas ◽  
P. B. Patra ◽  
M. C. Boral
Keyword(s):  
High Altitude ◽  
Plasma Volume ◽  
Body Fluid ◽  
Extracellular Fluid ◽  
Control Group ◽  
Bufo Melanostictus ◽  
Simulated High Altitude ◽  
Volume Blood ◽  
Total Body ◽  
Toad Bufo

Body fluid and hematologic changes were found in three groups of adult male toads that had been exposed to 48 h of continuous simulated altitudes of 12,000, 18,000, and 24,000 ft, respectively. Erythrocyte counts and hematocrit ratios were increased significantly in all the high-altitude-exposed animals compared with the control group of animals kept at sea level, whereas the hemoglobin concentrations were significantly increased only in the 18,000- and 24,000-ft-exposed animals. Exposure to high altitude generally caused a reduction of plasma volume, blood volume, extracellular fluid volume, and total body water. These reductions were markedly lower in the animals exposed to 24,000 ft. These simulated high-altitude effects on body fluids and hematology in the toad (Bufo melanostictus) were compared with those of the rat, birds, and humans acutely acutely exposed at various high altitudes and were found to be qualitatively similar.

Reduction of ICa,Land Ito1Density in Hypertrophied Right Ventricular Cells by Simulated High Altitude in Adult Rats

1997 ◽  
Vol 29 (1) ◽  
pp. 193-206 ◽  
Author(s):  
Christophe Chouabe ◽  
Leon Espinosa ◽  
Pierre Megas ◽  
Abderrazak Chakir ◽  
Oger Rougier ◽  
...  
Keyword(s):  
Right Ventricular ◽  
High Altitude ◽  
Adult Rats ◽  
Ventricular Cells ◽  
Simulated High Altitude

Relationship between Behavior in a Stress Situation and Later Separation from Flight Training with Expressed Anxiety toward Flying

1956 ◽  
Vol 2 (3) ◽  
pp. 393-397
Author(s):  
Robert B. Voas ◽  
John T. Bair ◽  
Rosalie K. Ambler
Keyword(s):  
High Altitude ◽  
Training Program ◽  
Flight Training ◽  
Stress Situation ◽  
Simulated High Altitude ◽  
Development Of Anxiety ◽  
The Relationship

The purpose of this research was to determine the relationship between reactions of cadets during simulated high altitude in a decompression chamber and the later development of anxiety toward flying as reported in terminal interviews. The results for 1540 cadets indicated that significantly more of those who withdrew because of anxiety toward flying had anxiety reactions in the decompression chamber than of those who completed the Naval Air Training Program.

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.

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