HYPOXIA 1 Hypoxia - Def i ciency in the amount of oxygen reaching the tissue. This can be led by a decrease of oxygen in the atmosphere or by means of physiological/pathological issues regarding the circulation of blood. This condition was noted by balloonists and alpinists during the early 1800's while reaching heights greater than 13000ft. After conducting some tests, it was soon found that the solution to reach higher altitudes was to obtain a supply of oxygen to suf f i ciently saturate the bloodstream. As the aviation industry was starting to grow during world war 2, the f i rst pressurized aircraft (Lockheed XC -35) was designed by the U.S Army Air Corps in the year 1937, to allow the cabin crew to breath without the need for oxygen masks at high altitudes. Three years later Boeing's 307 Stratoliner was transporting passengers in pressurised cabins at an altitude of 20000ft. From then to now, aircrafts have been designed to of fer the safest and most comfortable experience of pressurised cabins and have implemented actions to be taken during the onset of a pressurisation failure through several testing and accident investigations. This essay will explore the hazards that are present in all forms of aviation, the symptoms and ef f ects that occur and precautionary actions that can be and are taken to prevent the onset of hypoxia and examples of incidents where hypoxia was a major contributing factor. How does hypoxia occur: At sea level atmospheric pressure, the average human has around 103 mm Hg of Oxygen with a total of 760 mm Hg gas molecules inside the alveoli. However, after 10000ft the amount of saturated oxygen in the haemoglobin begins to decrease exponentially, where there is now only 55 mm Sea level 10,000 ft Hg of oxygen in the alveoli with a total of 523 mm Hg of total 103 02 55 particles at 10000ft. The saturation is around 90% at this altitude. This is due to the reduction in ambient air pressure with an increase in altitude which directly af f ects the partial pressure of No 381 oxygen getting into your body. By 20000ft the concentration of Ng 570 saturation of the blood would have been decreased to around CO2 40 65%. Other causes of hypoxia which are not common in aviation H2O 47 include Lung diseases (COPD, emphysema, etc.), Anemia, strong 523 mm Hg pain medications and drugs. Factors that would determine the CO2 40 H2O 47 severity of hypoxia are cabin temperature, altitude, physical 760 mm Hg Alveolar Gases fitness, rate of decent, smoking, stress, fatigue and the individual's ability to withstand hypoxia. Types of Hypoxia: 18,000 ft 39 N2 264 CO2 30 H2O 47 Air 380 mm Hg 1) Hypoxic Hypoxia - also known as Altitude Hypoxia is as its name suggests is caused by a reduction in the partial pressure of oxygen in the atmosphere due to a higher altitude. 2) Anaemic - occurs when the capacity of the oxygen in