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Carbon Monoxide Poisoning

Introduction:

  • Carbon Monoxide, chemically abbreviated as "CO," is one of the most common and toxic of substances in the aviation environment
  • Due to its properties as a colorless, odorless, and tasteless gas, it can quietly build, resulting in deadly consequences
  • It is therefore critical that pilots are able to recognize carbon monoxide poisoning
  • If discovered, pilots must apply immediate action to treat those symptoms before they get worse

Sources of Carbon Monoxide:

  • CO is a by-product of the incomplete combustion of carbon-containing materials, such as aviation fuel
  • While Carbon Monoxide poisoning can occur with or without environmental control operating, heating units are the most likely source of the problem
    • Most heaters in light aircraft work by air flowing over the manifold
    • Use of these heaters while exhaust fumes are escaping through manifold cracks and seals is responsible every year for several nonfatal and fatal aircraft accidents from carbon monoxide poisoning
  • It is possible to have a large amount of CO in your blood just by your environment to include polluted air and being around smokers, thereby reducing your tolerance before takeoff
Carbon Monoxide Symptoms
Carbon Monoxide Symptoms

Recognizing Carbon Monoxide Poisoning:

  • Carbon Monoxide Poisoning Symptoms:

    • Compounded with additional cues, knowing the symptoms, and recognizing them in your passengers, can be a key indicator
    • Carbon Monoxide has an affinity of 240 times that of oxygen which means it will more readily attach itself to your blood cells
    • Low concentrations over time can produce high blood concentration impeding the bloods ability to transport oxygen
      • As little as 10% Carboxyhemoglobin (Carbon Monoxide in the blood) can decreased peripheral and night vision
    • Symptoms will mirror that of hypoxia as an increase of CO in the blood implies you are actually suffering from hypemic hypoxia
    • Victims could expect: [Figure 1]
      • Sense of pressure in the head
      • Drowsiness
      • Dizziness
      • Roaring/ringing sensation of the ears
      • Confused and unable to think clear
      • Drunk appearance
      • Vomiting
      • Incontinent
      • Convulsions
      • Bounding pulse
      • Cherry red lips
      • Dilated pupils
      • Incapacitation
  • Aircraft Carbon Monoxide Detector
    Carbon Monoxide Detector
    Aircraft Carbon Monoxide Detector
    Hand-Held Carbon Monoxide Detector

    Carbon Monoxide Detection:

    • Due to its result from incomplete combustion, there will usually be odors or colors which can provide cues
      • Example: smelling exhaust is an indication of a leak and possible contamination
    • Since Carbon Monoxide is odorless it may be difficult to detect Carbon Monoxide until you or your passengers are experiencing symptoms, at which point any delay can be life threatening
    • Therefore, Carbon Monoxide detectors are cheap insurance which you would rather have and not need, than need and not have
      • Choosing a Carbon Monoxide Detector:

        • As demonstrated in the case studies, carbon monoxide is a life threatening poison
        • Carbon Monoxide detectors come in many designs but generally speaking you'll have the choice of either passive or electronic detectors
        • Passive Detectors:
          • A passive detector, such as the Quantum Eye Carbon Monoxide Detector are the most basic choice [Figure 2]
            • Advantages of Passive Detectors:
              • Low cost
              • Works independent of electrical power
            • Passive Detector Disadvantages:
              • Indicator must be monitored as it will not produce an alarm
              • Must be attached to something in view
        • Electronic Detectors:
          • Electronic detectors such as the Pocket CO Carbon Monoxide Detector are the more advanced types of detectors [Figure 3]
            • Advantages:
              • Audible alarms when carbon monoxide rises
              • Convenient enough to be carried at home or in a vehicle
            • Disadvantages:
              • Generally more expensive than passive detectors
              • Requires batteries

Immediate Action and Treatment:

  • Identify possible sources and attempt to isolate them
    • After removal from CO source, only about 0.5% is removed from blood every 4 hours
  • Use 100% oxygen and open windows to circulate fresh air
  • Monitor for further respiratory distress
    • Tell ATC that you suspect CO poisoning
    • Declare an emergency if you feel the situation warrants
  • Land as soon as possible!
  • If symptoms are severe or continue after landing, medical treatment should be sought
  • Once the situation has been resolved, have the aircraft inspected by a certified mechanic before its next flight

Carbon Monoxide Prevention:

  • The easy statement is to follow appropriate maintenance procedures
  • Carry a personal carbon monoxide detector, especially when renting
  • Pay special attention to the sources of carbon monoxide in the fall and winter months as damage may have occurred months before, but it does not manifest itself until cold weather arrives
  • More than that however, is to check potential sources prior to every flight

Carbon Monoxide Case Studies:

Conclusion:

  • Carbon Monoxide Poisoning in a silent killer who's risk can be mitigated through a few simple steps
  • It is incumbent on the pilot to conduct a thorough preflight which includes the exhaust/heating components to spot irregularities
  • After CO poisoning, it can take up to 24 hours to recover
  • Especially in winter months, refresh your knowledge on Carbon Monoxide and conduct an extra thorough preflight
    • Remember, the heater system may have gone unused for months
  • Additionally, ensure the Carbon Monoxide detector is in serviceable condition
  • For more information, see the Federal Aviation Administration (FAA) brochure called Carbon Monoxide: A Deadly Menace

Carbon Monoxide Poisoning Knowledge Quiz:

  1. What is the most common source of Carbon Monoxide poisoning in the aviation environment?
  2. Altitude
    Incomplete combustion
    Hyperventilation
    Alcohol usage

  3. What is NOT an expected symptom of Carbon Monoxide Poisoning?
  4. Drowsiness
    Vomiting
    Hyperventilation
    Cherry Red Lips

  5. Carbon Monoxide is a colorless, odorless, and tasteless gas
  6. True
    False

  7. It is possible to have a large amount of CO in your blood just by your environment
  8. True
    False

References: