Hyperventilation

Introduction:

WARNING:
All aeromedical topics are GENERALIZED.
Always consult with a doctor or physician to understand your specific situation

Possible Causes of Hyperventilation:

  • Hyperventilation
    Encyclopedia Britannica, Hyperventilation
  • Hyperventilation is an abnormal increase in the volume of air breathed in and out of the lungs [Figure 1]
    • Stress
    • Panic
    • Anxiety
    • Hypoxia
    • Decreased carbon dioxide in blood
    • 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 regulate the breathing process automatically
  • Hyperventilation
    Encyclopedia Britannica, Hyperventilation

Hyperventilation Symptoms:

  • As hyperventilation "blows off" excessive carbon dioxide from the body, a pilot can experience symptoms of:
    • Lightheadedness
    • 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 experiencing symptoms, the oxygen regulator should immediately be set to deliver 100%, and the system should be checked to ensure that it has been functioning effectively before giving attention to the 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 a 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 instead forces you to think about your breathing rate
      • This method may increase carbon dioxide levels too quickly, leaving it as a last resort
    • Recovery will occur within a few minutes
  • Remove the cause of stress, panic, or anxiety as able
    • If the source is an emergency that 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

Hyperventilation 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

Private Pilot - Human Factors Airman Certification Standards:

  • Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with personal health, flight physiology, and aeromedical and human factors related to safety of flight
  • References: AIM; FAA-H-8083-2, FAA-H-8083-3, FAA-H-8083-25
  • Private Pilot - Human Factors Lesson Plan

Human Factors Knowledge:

The applicant demonstrates understanding of:

Human Factors Risk Management:

The applicant demonstrates the ability to identify, assess and mitigate risks encompassing:

  • PA.I.H.R1:

    Aeromedical and physiological issues

  • PA.I.H.R2:

    Hazardous attitudes

  • PA.I.H.R3:

    Distractions, task prioritization, loss of situational awareness, or disorientation

  • PA.I.H.R4:

    Confirmation and expectation bias

Human Factors Skills:

The applicant exhibits the skill to:

Hyperventilation Knowledge Quiz:

Conclusion:

  • Hyperventilation is simply a matter of breathing too rapidly
  • It is seldom completely incapacitating, but it does produce one or more of the symptoms that are disturbing, if not alarming, to the uninformed pilot
  • Hyperventilation can look just like hypoxia, depending on the symptoms displayed, and has resulted in numerous fatal accidents
  • Understand the symptoms and how you will recognize them in yourself and your passengers, along with the appropriate recovery method
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