Clinical Trial: Effects of Aircraft Cabin Altitude on Passenger Comfort and Discomfort
Study Status: Completed
Recruit Status: Completed
Study Type: Interventional
Official Title: Investigation to Determine the Effects of Aircraft Cabin Altitudes on Passenger Comfort and Discomfort
Brief Summary:
Commercial aircraft passengers are exposed to atmospheric pressures ranging from the pressure found at ground level to that encountered in the external environment at 8,000 feet. There is some evidence in the medical literature that symptoms of acute mountain sickness can result from ascent to altitudes of 6,300 to 10,000 feet by unacclimated persons during the first few days following ascent, probably due to the hypoxia that results from breathing air at the reduced ambient pressures at altitude. The logical hypothesis that follows is that exposure to 8,000 feet could cause hypoxia sufficient to adversely affect the comfort and well being of some commercial aircraft passengers on prolonged flights. There is insufficient data in the literature to validate this hypothesis.
Exercise at sea level and at altitude reduces arterial oxygen levels. The logical hypothesis that follows is that the combination of moderate exercise and exposure to altitude could cause hypoxia sufficiently severe to adversely affect the comfort and well being of some people and that the combined effect of exercise and altitude on comfort and well being is greater than the effect of exercise or altitude alone. Again, there is insufficient evidence in the literature to substantiate this possibility.
The purpose of this investigation is to test these hypotheses.
Detailed Summary:
Altitude affects human health and well being through its effect on tissue oxygenation by altering the partial pressure of oxygen in the gas that enters the lungs. The partial pressure of any component of a mixed gas is equal to the total pressure of the gas multiplied by the fraction of the gas that is made up by the component--approximately 78% for nitrogen and 21% for oxygen in air at all altitudes. As altitude increases, total air pressure decreases and consequently, the partial pressures of all component gases, including oxygen, decrease. As air is inhaled, it becomes saturated with water vapor from body tissues, further reducing its partial pressure of oxygen. Tissue oxygenation, measured in terms of partial pressure of oxygen in arterial blood (paO2), is directly related to the partial pressure of oxygen in the gas entering the lungs.
The United States Federal Aviation Agency requires that commercial aircraft be designed so that the barometric pressure in the cabin at maximum cruise altitude exceeds that found in the external atmosphere at 8,000 feet (565 mm Hg).1 The scientific basis for this limit is unclear. Although there is a large body of knowledge concerning the effects of altitude on humans, most of it involves healthy young people at altitudes higher than 8,000 feet. An investigation of the effects of altitude on commercial airline passengers performed by McFarland in 1937 found “…older persons up to 72 years of age respond to moderate altitudes, i.e., up to 16,000 feet, without unusual difficulties.” However, the same author went on to conclude, “The human factors analysis presented here would suggest that the comfort and well-being of airline passengers would be significantly benefited by as near sea level conditions as possible. In any event, cabin altitudes of 3,000 – 5,000 feet should not be exceeded.” 2, 3 In 1986,
Sponsor: The Boeing Company
Current Primary Outcome:
- ESQ IV factor scores measured at 2 hour intervals
- Oxygen Saturation measured at 2 hour intervals
Original Primary Outcome: Same as current
Current Secondary Outcome:
Original Secondary Outcome:
Information By: The Boeing Company
Dates:
Date Received: May 15, 2006
Date Started: October 2002
Date Completion: April 2003
Last Updated: October 16, 2006
Last Verified: May 2006
