Under conditions of stress and anxiety, a person's body reacts automatically to such stimuli whether the danger be imaginary or real
One of these automatic reactions is a marked increase in breathing rate which results in a significant decrease in the carbon dioxide content of the blood which is necessary to automatically regulate the breathing process
Hyperventilation Symptoms:
As hyperventilation "blows off" excessive carbon dioxide from the body, a pilot can experience symptoms of
Lightheadness
Nausea
Suffocation
Drowsiness
Tingling in the extremities
Coolness
Dry mouth
Blurred vision
Rapid pulse and breathing rate
Early symptoms of hyperventilation are similar to those of hypoxia and some to ordinary airsickness
Symptoms of both are not unique and several can occur at the same time
Therefore, if a pilot is using an oxygen system when symptoms are experienced, the oxygen regulator should immediately be set to deliver 100% oxygen and the system checked to assure that it has been functioning effectively before giving attention to rate and depth of breathing
Symptoms can easily cause confusion and panic which only aggravates the problem by further increasing anxiety, and thus the breathing rate
Effects of Hyperventilation:
First and foremost, hyperventilation can be a significant distraction to the safe operation of the aircraft
Incapacitation can eventually result from lack of coordination, disorientation, and painful muscle spasms
Eventually, unconsciousness can occur
Recovering from Hyperventilation:
The symptoms of hyperventilation subside within a few minutes after the rate and depth of breathing are consciously brought back under control
The buildup of carbon dioxide in the body can be hastened by talking loudly, or controlled breathing in and out of a paper bag held over the nose and mouth
This method does not force you to breathe carbon dioxide but rather forces you to think about your breathing rate
This method is not recommended unless absolutely necessary as it may increase carbon dioxide levels too quickly
Recovery will occur within a few minutes
Remove cause of stress, panic, or anxiety, as able
If the source is an emergency which must be dealt with immediately, take a moment and remember your emergency procedure training
If incapacitation occurs then the body will naturally recover from the situation and slow the breathing rate
Case Studies:
NTSB Identification: ATL90LA025 The National Transportation Safety Board determines the probable cause(s) of this accident to be: Pilot's temporary physical condition (possible hyperventilation or anxiety attack). Soft terrain in the emergency landing was considered to be a related factor
NTSB Identification: DEN82DA125 The National Transportation Safety Board determines the probable cause(s) of this accident to be: Physical impairment (other organic problem of the pilot in command
NTSB Identification: MIA78DLA01 The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot in command's misjudgment of distance and speed and physical impairment from hyperventilation
Airman Certification Standards:
Determine that the applicant exhibits knowledge of the elements related to aeromedical factors by explaining:
