EFFECTS OF PRESSURE
When in flight, atmospheric pressure changes have many effects on the human body. Although the cabin of an aircraft is pressurized, imitating the pressure on the ground is nearly impossible. When an aircraft is pressurized at cruising altitude, oxygen pressure is reduced by about 15-20%. This equates to between 5,000 and 8,000 AMSL. This decrease can create complications to our bodies such as hypoxia, pressure in the sinuses and ears as well as trapped air in the gastrointestinal system.
Sinuses are cavities in the skull filled with air. They are sensitive to pressure changes, as well as infection and foreign bodies. Sinuses are located on both sides of your nose, between the eyes and in your forehead. Pressure changes can create pain in these areas, perhaps even radiating to your upper dental arch. For this reason, flying with a respiratory infection can create discomfort.
Pressure in the eustachian tubes of the ears manifests itself most commonly on take off and landing. You may feel pressure, pain, a plugged feeling and may hear a squealing or echo sound.
This pressure can usually be relieved by swallowing. Swallowing can open the eustachian tubes, allowing the pressure in the ears to equalize. Infants should be offered a pacifier or, preferably, liquid to force the act of swallowing. Adults and children can equalize this pressure by swallowing, yawning or chewing gum.
When these techniques fail, the Valsalva maneuver may be used. Valsalva is performed by moderately forcing air out through a closed airway. This can be accomplished by closing your lips and pinching your nose. Attempt to gently but forcefully blow out your closed nose. If it doesn’t work, wait a few minutes and repeat the process of swallowing, yawning and utilizing the Valsalva maneuver.
Your gastrointestinal system also contains air. This air will react similarly to pressure changes and can create a feeling of bloating, discomfort and the need to pass gas. This can be worsened by the intake of gas-producing foods and drinks such as legumes, carbonated soft drinks or sparkling wines.
The effects of pressure changes can also create a condition known as barodontalgia. “Flyer’s toothache” is a relatively uncommon event. The problem is exacerbated when recent dental treatment has been completed or when dental treatment due to decay is needed. This can also occur as a result of a pulpitis (inflamed nerve of a tooth).
There is little that can be done; symptoms will subside upon landing. The use of over- the-counter anti-
Other Medical Emergencies 81
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