High Altitude Physiology and Human Factors

1. High Altitude Physiology and Human Factors Audio required make sure your volume is tuned up! October 4, 2006

2. Introduction • Define the atmosphere in terms of its characteristics and human adaptability. • Describe how gases in our bodies will respond to changes in the environment, and how this impacts our performance. • Review causes and hazards of hypoxia and hyperventilation

4. As we ascend • The combination of pressure and oxygen percentage determine our ability to perform. • What altitudes do you first notice effects? • Our environment changes… • predictably, • gradually, • to the point where we are in a hostile environment, • and well beyond our ability to adapt and survive.

5. HYPOXIA

6. Types of Hypoxia and Causes • Hypoxic • Histotoxic • Hypemic • Stagnant

7. Hypoxic Hypoxia • A lack of oxygen partial pressure in the lungs or a reduction in the gas exchange area caused by: • Altitude • Drowning • Pneumonia • Chronic Lung Disease • Location of Impediment • Lungs • Hypoxic hypoxia is the most common cause of hypoxia for a pilot due to an oxygen deficiency associated with high altitude operations

8. Effective Performance Times Effective Performance Times should always be a consideration. At 25,000 feet, the maximum altitude of the Cirrus, the time of useful consciousness is about 3-5 minutes. It is extremely important to continually monitor the oxygen system at be prepared to deal immediately with any oxygen malfunction.

9. Histotoxic Hypoxia • The lack of oxygen intake into the cell (tissue poisoning) caused by: • Alcohol • Narcotics • Location of Impediment • Cells • Histotoxic hypoxia is dependent on factors other than altitude.

10. Hypemic Hypoxia • Inability of the blood to carry oxygen caused by: • Carbon Monoxide Poisoning • Smoking • Fire creates toxins that can irritate and incapacitate • Anemia • Location of Impediment • Blood • Carbon monoxide and smoking create an oxygen carrying deficiency which will degrade pilot performance

11. Stagnant Hypoxia • Lack of proper blood distribution caused by: • “G” forces • Shock, fainting, etc. • Heart Failure • Cold Temperature • Location of Impediment • Blood Transportation Problem • Steep turns at FL250 may not be a good idea

12. Air Hunger Headache Nausea Hot & Cold Flashes Euphoria Tingling Apprehension Dizziness Fatigue Blurred Vision Tunnel Vision Numbness Mental Confusion Increase in rate and depth of breathing Cyanosis Belligerence Poor Judgment Loss of muscle coordination Euphoria Unconsciousness Subjective Symptoms Objective Signs

13. Altitude Individual Tolerance Environmental Temperature Psychological Factors Alcohol/Smoking Rate of Ascent Physical Activity Duration of Exposure Physical Fitness Medications Rate of Decompression Factors influencing hypoxia

14. Prevention • Use oxygen in compliance with the regulations 15,000 MSL:Crew must use Oxygen, and must be provided to each occupant 14,000 MSL:Crew must use Oxygen for flights duration 12,500 MSL:Crew must use Oxygen after 30 min

15. Prevention and Considerations • Use of pulse oximeter • Adjust the flow of oxygen to maintain saturation levels above 90% • Cannulas vs Masks • Cannulas can not be used above FL180 as per FAR part 23 • Remember where the source of oxygen is from when using a cannula. Eating and talking will decrease the amount of oxygen that is available to your lungs

16. Prevention and Considerations • Passengers • Monitor passengers for signs of hypoxia and treat accordingly • Passengers should be briefed on the use of oxygen during preflight • When to use start using oxygen?

17. Treatment for Hypoxia • Recognition of hypoxia • 100% Oxygen • Return Rate and Depth of Breathing to Normal • Check Connections • Check adjustment and size of mask • Descend Below 10,000 feet • Terrain permitting • SCREAM • Supply • Connections • Regulator • Emergency connection • Adjustment • Mask condition

18. Hyperventilation

19. An abnormal increase in the rate and depth of breathing. Results in exhaling too much Carbon Dioxide. Voluntary Emotional Fear Anxiety Stress Tension Pain Pressure Breathing Hypoxia Hyperventilation

20. Dizziness Faintness Visual Problems Tingling Nausea Light Headedness Muscle Twitching Cold, clammy skin Muscle Tightness Paleness Unconsciousness Subjective Symptoms Objective Signs

21. Hypoxic Hypoxia - Hyperventilation Comparison

22. 100% Oxygen Return Rate and Depth of Breathing to Normal Check Connections Paper Bag Method Used at altitude where supplemental oxygen is not required or needed Talk or sing to control the rate of breathing. Treatment for Hyperventilation

23. Other Physiological Affects of Altitude/Pressure Change • Decompression sickness • Caused by the formation of nitrogen bubbles in the blood and tissues following a sudden drop in the surrounding pressure, as when ascending rapidly. • Characterized by severe pains in the joints and chest, skin irritation, cramps, and paralysis • Treatment • Decompression sickness is a medical emergency, respond appropriately. • NOTE: Time between scuba diving on non-decompression stop dives and flying is 12 hours. The minimum time between decompression stop diving and flying is 24 hours.

24. Other Physiological Affects of Altitude/Pressure Change • Sinus/inner ear blockage • Caused by the difference in pressure from the middle ear and the outside world, most likely due to a cold, ear infection or a sore throat. • Treatment • On descent, level off and Valsalva • Reverse direction of pressure change • Retry Valsalva • Use reduced rates of descent and land The eustachian tube allows air pressure to equalize in the middle ear.

25. Conclusion • Remember the atmosphere that we live in is much different up at altitude than it is down on the surface. • As a pilot you must be prepared for any physiological situation that may arise. • You must be able to recognize the symptoms of Hypoxia and Hyperventilation as well as be able to take the appropriate action in order to prevent conditions from getting worse.

26. UNDAF Altitude Chamber FAA Physiological Training Highly recommended Experience conditions that can lead to hypoxia Learn to recognize hypoxia Learn about other physiological limitations when flying Physiological Training