Aviation Medicine

Question 1

What is hypoxia? How to recognise and manage it?

Answer 1

• A condition where supply of Oxygen to body’s cells is inadequate

Recognition

• Mild: fatigue, listlessness, lack of concentration
• Moderate: lack of self-criticism, mood changes & confusion, breathlessness
• Severe: cyanosis (blue tinge to fingers & lips), unconsciousness, death

Management

1. Provide oxygen at 4L per min (HI)
2. Loosen tight clothing around neck, chest and waist
3. Monitor pax

Question 2

What is hyperventilation? How to recognise and manage it?

Answer 2

• Act of rapid / deep breathing most commonly due to anxiety or panic
• Excessive breathing often leaves person feeling breathless

Recognition

• rapid / over breathing
• numbness & tingling of body extremities (pins & needles)
• spasms in hands & feet
• agitation, dizziness, panic
• vision disturbances
• fainting

Management

1. Reassure pax with calmness, ask them to take slower but deeper breaths
2. Give oxygen at 4L rate (HI)

Question 3

Gas expansion and the effects (body parts) with altitude?

Answer 3

• The inverse relationship between atmospheric pressure and gas volume affects gases within the body at altitude
• Common body parts affected by gases:

a) Ears
- pressure equalisation is regulated by the Eustachian tube
- if tube is blocked (usually by URTI), ears can experience severe discomfort including pain and lead to possible rupture of eardrums
- symptoms of URTI: cold / flu, sinus or throat infection, hay fever

Recognition
- pax complaining of increasing ear pain during descent

Management

1. Instruct pax to chew, yawn or move lower jaw to try and open up bottom end of Eustachian tube
2. If unsuccessful, ask pax to perform “Valsalva” manoeuvre by taking deep breath in and closing the mouth. Immediately pinch the nostrils, blow hard and swallow the air; repeat action during descent
3. Infants to be encouraged to suck on a bottle or dummy, or allowed to cry vigorously
4. If pain persists with descent, apply warmth to outer ear and advise pax to seek medical attention. ** DO NOT USE PAPER CUPS & PLACE OVER EAR

b) Sinuses
- air pockets situated in the facial bones; the narrow canals opening into the nose control pressure equalisation
- blocked sinuses due to cold and infections can cause severe pain with changing pressure i.e. sinus barotrauma

Management

1. Instruct pax to blow nose forcibly one side at a time

c) Alimentary canal (bowel)
- gases produced during digestion expand with increasing altitude
- bowel discomfort rarely occurs during in-flight, however the exception is if a cabin decompression event occurs

d) Teeth
- tooth decay (hollow cavity) can affect trapped gases in the body from escaping during ascent; great pressure is applied on the nerve endings causing teeth pain and discomfort

Management

1. Apply ice pack to area (constricts blood vessels to limit inflammation & swelling)
2. Provide pax with Panadol or aspirin for pain relief if requested

Question 4

What is decompression sickness? How to recognise and manage it?

Answer 4

• A condition where gas bubble formation occurs in the body as a result of atmospheric pressure changes
• Nitrogen (present in body fluids & tissues) that is forced to leave too rapidly due to the decrease in atmospheric pressure will cause bubble formation in different areas of the body

Recognition

• The Bends = painful joints i.e. elbow, shoulder, hip, wrist, knee, ankle
• The Chokes = pain in chest; dry hacking cough
• The Creeps = itching sensations of the skin, sometimes accompanied by red rash

** other symptoms include “nervous system effects” and “collapse”

Management

1. Inform FD to emergency descend
2. Administer oxygen
3. Keep warm and restrict body movement (prevents air embolism i.e. nitrogen bubbles from moving towards other parts of the body)
4. If pax conscious - lie flat; if unconscious - recovery position
5. Divert to nearest airport with hyperbaric chamber (for oxygen therapy) and seek medical attention