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

Introduction Define the atmosphere in terms of its characteristics and human adaptability. 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. 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 Review causes and hazards of hypoxia and hyperventilation

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

HYPOXIA

Types of Hypoxia and Causes Stagnant Hypemic Histotoxic Hypoxic

Hypoxic Hypoxia A lack of oxygen partial pressure in the lungs or a reduction in the gas exchange area caused by: A lack of oxygen partial pressure in the lungs or a reduction in the gas exchange area caused by: AltitudeAltitude DrowningDrowning PneumoniaPneumonia Chronic Lung DiseaseChronic Lung Disease Location of Impediment Location of Impediment LungsLungs Hypoxic hypoxia is the most common cause of hypoxia for a pilot due to an oxygen deficiency associated with high altitude operations Hypoxic hypoxia is the most common cause of hypoxia for a pilot due to an oxygen deficiency associated with high altitude operations

Effective Performance Times Time of Useful Consciousness FL minutes FL minutes FL minutes FL minutes FL seconds FL seconds FL500 and above 9-12 seconds 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.

Histotoxic Hypoxia The lack of oxygen intake into the cell (tissue poisoning) caused by: The lack of oxygen intake into the cell (tissue poisoning) caused by: AlcoholAlcohol NarcoticsNarcotics Location of Impediment Location of Impediment CellsCells Histotoxic hypoxia is dependent on factors other than altitude. Histotoxic hypoxia is dependent on factors other than altitude.

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

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

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

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

Prevention Use oxygen in compliance with the regulations 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

Prevention and Considerations Use of pulse oximeter Use of pulse oximeter Adjust the flow of oxygen to maintain saturation levels above 90%Adjust the flow of oxygen to maintain saturation levels above 90% Cannulas vs Masks Cannulas vs Masks Cannulas can not be used above FL180 as per FAR part 23Cannulas 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 lungsRemember 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

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

Treatment for Hypoxia Recognition of hypoxia Recognition of hypoxia 100% Oxygen 100% Oxygen Return Rate and Depth of Breathing to Normal Return Rate and Depth of Breathing to Normal Check Connections Check Connections Check adjustment and size of mask Check adjustment and size of mask Descend Below 10,000 feet Descend Below 10,000 feet Terrain permittingTerrain permitting SCREAM SCREAM SupplySupply ConnectionsConnections RegulatorRegulator Emergency connectionEmergency connection AdjustmentAdjustment Mask conditionMask condition

Hyperventilation

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

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

Hypoxic Hypoxia - Hyperventilation Comparison SignsHyperventilationHypoxia OnsetGradual Varies with altitude Muscle Activity SpasmFlaccid Skin Appearance Pale, Clammy Cyanosis TetanyPresentAbsent DizzinessXX EuphoriaXX FatigueXX HeadacheXX Poor Judgment XX Light headiness XX TinglingXX

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

Other Physiological Affects of Altitude/Pressure Change Decompression sickness 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.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 paralysisCharacterized by severe pains in the joints and chest, skin irritation, cramps, and paralysis Treatment Treatment Decompression sickness is a medical emergency, respond appropriately.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.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.

Other Physiological Affects of Altitude/Pressure Change Sinus/inner ear blockage 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.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. TreatmentTreatment On descent, level off and Valsalva On descent, level off and Valsalva Reverse direction of pressure change Reverse direction of pressure change Retry Valsalva Retry Valsalva Use reduced rates of descent and land Use reduced rates of descent and land The eustachian tube allows air pressure to equalize in the middle ear.

Conclusion Remember the atmosphere that we live in is much different up at altitude than it is down on the surface. 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. 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. 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.

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