1 Aviation Medicine CHAPTER 05 TOXIC FUMES 71

  1. CHAPTER 5. TOXIC FUMES
  2. There are many sources of toxic gases in aviation including the following:
    • a) combustion products from engines, b) fuels,
    • c) lubricants,
    • d) hydraulic fluids, e) anti?icing fluid, f) coolants,
    • g) fire extinguishers, h) refrigerants,
    • i) ozone, and
    • j) agricultural chemicals.
  3. CHAPTER 5. TOXIC FUMES
    • -all fumes detected in the aircraft are potentially lethal
    • -commonest sources of fumes in transport aircraft
  4. -Fuel spilled from engines or machinery carried on board.
    -additional hazard of explosion and fire.
  5. CHAPTER 5. TOXIC FUMES
    • -Fumes usually arise during combustion
    • - with many types of chemicals being produced.
    • - Particularly hazardous fumes are given off when
    • - hydrocarbons,
    • -plastics,
    • -polystyrene and
    • -other synthetic products
  6. all these substances are common in aircraft interiors.
  7. CHAPTER 5. TOXIC FUMES
    • Fumes may contain
    • -carbon monoxide,
    • -carbon dioxide,
    • -hydrogen cyanide,
    • -aldehydes,
    • - ammonia,
    • -benzene, -
    • -phenol, -sulphur dioxide, and
    • acrolein. Some of these gases may be lethal or at best, irritating and incapacitating.
  8. CHAPTER 5. TOXIC FUMES
    • Symptoms of toxic gases or fumes
    • -may mimic those of either hypoxia or hyperventilation
    • - some toxic fumes directly causing hypoxia.
  9. CHAPTER 5. TOXIC FUMES
    • Other symptoms include:
    • a) eye and mucous membrane irritation, b) nausea,
    • c) vomiting, d) confusion,
    • e) disorientation, and f) headache.
  10. CHAPTER 5. TOXIC FUMES
    • Onset of symptoms
    • -may be insidious (eg. carbon monoxide) and may be confused with hypoxia.
    • - can cause incapacitation without warning,
    • - cause subtle impairment of the aircrew?s ability to fly the aircraft.
  11. CHAPTER 5. TOXIC FUMES
    • If toxic fumes are involved,
    • -odour and eye or throat irritation may be present.
    • -These are not typical symptoms when exposed to hypobaric (hypoxic) hypoxia.
  12. CHAPTER 5. TOXIC FUMES
    • smoke
    • -will also impair vision
    • - unable to read instruments or fly visually.
  13. CHAPTER 5. TOXIC FUMES
    • CARBON MONOXIDE
    • - is extremely hazardous
    • - insidious nature and incapacitating effects.
    • -Like hypoxic hypoxia, its onset can be very subtle.
    • -binds to haemoglobin
  14. CHAPTER 5. TOXIC FUMES
    • CARBON MONOXIDE
    • Why Carbon monoxide more toxic
    • -200 ? 300 times the affinity of oxygen and forms a molecule called carboxyhaemoglobin.
    • - CO displaces oxygen from the Hb binding sites,
    • - the oxygen carrying capacity of blood is reduced.
  15. CHAPTER 5. TOXIC FUMES
    • CARBON MONOXIDE
    • What other effects of CO.
  16. have a histotoxic effect on the nervous system with neurological symptoms being common.
  17. CHAPTER 5. TOXIC FUMES
    • CARBON MONOXIDE
    • Symptoms of CO poisoning may include:
    • CNS Sx
    • a) headache, b) weakness, c) dizziness,
    • d) confusion,
    • e) unconsciousness,
  18. f)shortness of breath
    g) cherry?red flushing of the skin may also be noticed.
  19. CHAPTER 5. TOXIC FUMES
    • CARBON MONOXIDE
    • Continued exposure to carbon monoxide
  20. will often be fatal with treatment of severe poisoning usually requiring hyperbaric oxygen therapy.
  21. CHAPTER 5. TOXIC FUMES
    • HYDROCARBONS
    • -Fuels are made of many different types of hydrocarbons
    • - carry the risk of explosion and fire.
    • - greatest risk is on the ground during refueling operations.
    • - can result in chemical burns.
    • - Susceptible individuals can develop contact dermatitis.
  22. CHAPTER 5. TOXIC FUMES
    • HYDROCARBONS
    • Inhalation of fuel fumes
    • -neurological effects,
    • - usually headache and narcosis.
    • -large doses can result in coma, convulsions and death.
  23. CHAPTER 5. TOXIC FUMES
    • HYDROCARBONS
    • Hydraulic fluids
    • -are not as volatile as fuels.
    • -can be aerosolized at high pressure and leak into the cabin after a system failure.
    • - Most are non?toxic unless burnt,
  24. CHAPTER 5. TOXIC FUMES
    • HYDROCARBONS
    • Castor oil based fluid
    • - Inhalation of these results in headache, dizziness, impaired vision and confusion.
  25. CHAPTER 5. TOXIC FUMES
    • HYDROCARBONS
    • Leaks due to mechanical failures
    • = can contaminate cabin air with oil vapors or mists.
    • -irritation of the eyes and respiratory tract,
    • -headache, nausea,
    • - pneumonitis(chemical inflammation of the lungs)
  26. CHAPTER 5. TOXIC FUMES
    • HYDROGEN CYANIDE
    • - extremely potent histotoxic agent.
    • - produced in fires when plastics and synthetic materials burn.
    • - interfere with all cells? ability to utilize oxygen in the mitochondria to produce energy (ATP) (oxidative phosphorylation).
  27. CHAPTER 5. TOXIC FUMES
    • OZONE
    • - tri?atomic form of oxygen, O3.
    • - is a blue, unstable oxidant gas
    • - toxic to humans.
    • - occurs naturally in the stratosphere between 40 ? 140,000 feet.
  28. CHAPTER 5. TOXIC FUMES
    • Ozone
    • How is it produced
    • Function
    • -produced when UV ight reacts with molecular oxygen
    • -protects the surface of the earth form UV radiation by absorption
  29. CHAPTER 5. TOXIC FUMES
    • Ozone
    • How else can Ozone be -can also be produced artificially by electrical discharges, such as electric motors and by lightening
  30. CHAPTER 5. TOXIC FUMES
    • Ozone
    • toxic effects mainly the respiratory tractjQuery110107462365925755379_1487673832556
    • causes lung irritation
    • - decreased lung function and coughing at just 1.0 ppm
    • -10 ppm is enough to causes fatal leakage of fluid into the lungs (pulmonary oedema)?
    • --is unstable and breaks down when heated
    • - Air drawn from the engines in pressurised aircraft therefore has very little ozone in it
  31. CHAPTER 5. TOXIC FUMES
    EMERGENCY ACTIONS FOR TOXIC FUMES
  32. - same as the corrective actions for hypoxia
    • -Ventilate the cabin
    • -Select emergency pressure on the regulator (ward flow of O2 preventing toxic gases from entering the mask.
    • -Declare an emergency
    • -Land as soon as possible.
  33. CHAPTER 5. TOXIC FUMES
    • EMERGENCY ACTIONS FOR TOXIC FUMES
    • Actions if you suspect toxic fumes in the cabin are:
    • a) Select 100 % oxygen,
    • b) Select emergency pressure, c) Toggle down,
    • d) Check connections?push,
    • e) Breathe at normal rate and depth, f) Declare an emergency,
    • g) Descend and land ASAP, and h) Ventilate cabin.
  34. Unpressurised Aircraft not fitted with oxygen systems eg( CT?4B training aircraf, the following is recommended:
  35. ? BOLD TYPE ACTIONS (AL2)
    • ? Hot and cold air control knobs ? closed,
    • ? Punkah louvres ? closed,
    • ? Land as soon as practicable, and
    • ? CO Indicator ? continue to monitor.
  36. ? If CO indicator darkens further, heater used, or if fumes are present:
    • ? Hot air control knob ? closed,
    • ? Cold air control knob ? open,
    • ? Punkah louvers ? open, and
    • ? Land as soon as practicable.
  37. ? Be alert for signs of Hypoxia.
  38. Figure 5?1 summarises the actions that should be taken following a smoke and fumes incident.
  39. FIGURE 5?1. SMOKE AND FUMES ACTION SUMMARY
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1 Aviation Medicine CHAPTER 05 TOXIC FUMES 71
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1 Aviation Medicine CHAPTER 05 TOXIC FUMES 71
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