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

High Altitude Physiology High Altitude Physiology and Human Factorsand Human Factors

October 4, 2006

Audio required make sure your volume is tuned up!

IntroductionIntroduction

Define the atmosphere in terms of its Define the atmosphere in terms of its characteristics and human characteristics and human adaptability.adaptability.

Describe how gases in our bodies will Describe how gases in our bodies will respond to changes in the respond to changes in the environment, and how this impacts environment, and how this impacts our performance.our performance.

Review causes and hazards of Review causes and hazards of hypoxia and hyperventilationhypoxia and hyperventilation

As we ascendAs we ascend The combination of The combination of

pressure and oxygen pressure and oxygen percentage determine our percentage determine our ability to perform.ability to perform.

What altitudes do you first What altitudes do you first notice effects?notice effects?

Our environment Our environment changes…changes…• predictably,predictably,• gradually, gradually, • to the point where we are to the point where we are

in a hostile environment,in a hostile environment,• and well beyond our ability and well beyond our ability

to adapt and survive.to adapt and survive.

HYPOXIAHYPOXIA

Types of Hypoxia and CausesTypes of Hypoxia and Causes

• Stagnant

• Hypemic

• Histotoxic

• Hypoxic

Hypoxic HypoxiaHypoxic Hypoxia A lack of oxygen partial pressure in the lungs or a reduction A lack of oxygen partial pressure in the lungs or a reduction

in the gas exchange area caused by:in the gas exchange area caused by:• AltitudeAltitude• DrowningDrowning• PneumoniaPneumonia• Chronic Lung DiseaseChronic Lung Disease

Location of ImpedimentLocation of Impediment• LungsLungs

Hypoxic hypoxia is the most common cause of hypoxia for Hypoxic hypoxia is the most common cause of hypoxia for a pilot due to an oxygen deficiency associated with high a pilot due to an oxygen deficiency associated with high altitude operationsaltitude operations

Effective Performance TimesEffective Performance Times

Time of Useful ConsciousnessTime of Useful ConsciousnessFL180FL180 20-30 minutes20-30 minutes

FL220FL220 8-10 minutes8-10 minutes

FL250FL250 3-5 minutes3-5 minutes

FL300FL300 1-2 minutes1-2 minutes

FL350FL350 30-60 seconds30-60 seconds

FL430FL430 9-12 seconds9-12 seconds

FL500 and FL500 and aboveabove

9-12 seconds9-12 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 HypoxiaHistotoxic Hypoxia

The lack of oxygen intake into the cell (tissue The lack of oxygen intake into the cell (tissue poisoning) caused by:poisoning) caused by:• AlcoholAlcohol• NarcoticsNarcotics

Location of ImpedimentLocation of Impediment• CellsCells

Histotoxic hypoxia is dependent on factors other Histotoxic hypoxia is dependent on factors other than altitude. than altitude.

Hypemic HypoxiaHypemic Hypoxia Inability of the blood to carry oxygen caused by:Inability of the blood to carry oxygen caused by:

• Carbon Monoxide PoisoningCarbon Monoxide Poisoning SmokingSmoking Fire creates toxins that can irritate and incapacitateFire creates toxins that can irritate and incapacitate

• AnemiaAnemia

Location of ImpedimentLocation of Impediment• BloodBlood

Carbon monoxide and smoking create an oxygen Carbon monoxide and smoking create an oxygen carrying deficiency which will degrade pilot carrying deficiency which will degrade pilot performanceperformance

Stagnant HypoxiaStagnant Hypoxia Lack of proper blood distribution caused by:Lack of proper blood distribution caused by:

• ““G” forcesG” forces• Shock, fainting, etc.Shock, fainting, etc.• Heart FailureHeart Failure• Cold TemperatureCold Temperature

Location of ImpedimentLocation of Impediment• Blood Transportation ProblemBlood Transportation Problem

Steep turns at FL250 may not be a good ideaSteep turns at FL250 may not be a good idea

Subjective SymptomsSubjective Symptoms

Air HungerAir Hunger HeadacheHeadache NauseaNausea Hot & Cold FlashesHot & Cold Flashes EuphoriaEuphoria TinglingTingling ApprehensionApprehension DizzinessDizziness FatigueFatigue Blurred VisionBlurred Vision Tunnel VisionTunnel Vision NumbnessNumbness

Mental ConfusionMental Confusion Increase in rate and Increase in rate and

depth of breathingdepth of breathing CyanosisCyanosis BelligerenceBelligerence Poor JudgmentPoor Judgment Loss of muscle Loss of muscle

coordinationcoordination EuphoriaEuphoria UnconsciousnessUnconsciousness

Objective SignsObjective Signs

Factors influencing hypoxiaFactors influencing hypoxia AltitudeAltitude Individual ToleranceIndividual Tolerance Environmental Environmental

TemperatureTemperature Psychological FactorsPsychological Factors Alcohol/SmokingAlcohol/Smoking

Rate of AscentRate of Ascent Physical ActivityPhysical Activity Duration of ExposureDuration of Exposure Physical FitnessPhysical Fitness MedicationsMedications Rate of DecompressionRate of Decompression

PreventionPrevention

Use oxygen in compliance with the Use oxygen in compliance with the regulationsregulations

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 ConsiderationsPrevention and Considerations

Use of pulse oximeterUse of pulse oximeter• Adjust the flow of oxygen Adjust the flow of oxygen

to maintain saturation to maintain saturation levels above 90%levels above 90%

Cannulas vs MasksCannulas vs Masks• Cannulas can not be used Cannulas can not be used

above FL180 as per FAR above FL180 as per FAR part 23part 23

• Remember where the Remember where the source of oxygen is from source of oxygen is from when using a cannula. when using a cannula. Eating and talking will Eating and talking will decrease the amount of decrease the amount of oxygen that is available to oxygen that is available to your lungsyour lungs

Prevention and ConsiderationsPrevention and Considerations

PassengersPassengers• Monitor passengers for Monitor passengers for

signs of hypoxia and signs of hypoxia and treat accordinglytreat accordingly

• Passengers should be Passengers should be briefed on the use of briefed on the use of oxygen during preflightoxygen during preflight

When to use start When to use start using oxygen?using oxygen?

Treatment for HypoxiaTreatment for Hypoxia Recognition of hypoxiaRecognition of hypoxia 100% Oxygen100% Oxygen Return Rate and Depth of Return Rate and Depth of

Breathing to NormalBreathing to Normal Check ConnectionsCheck Connections Check adjustment and size of Check adjustment and size of

maskmask Descend Below 10,000 feetDescend Below 10,000 feet

• Terrain permittingTerrain permitting SCREAMSCREAM

• SupplySupply• ConnectionsConnections• RegulatorRegulator• Emergency connectionEmergency connection• AdjustmentAdjustment• Mask conditionMask condition

HyperventilationHyperventilation

An abnormal An abnormal increase in the rate increase in the rate and depth of and depth of breathing.breathing.

Results in exhaling Results in exhaling too much Carbon too much Carbon Dioxide.Dioxide.

VoluntaryVoluntary EmotionalEmotional

• FearFear• AnxietyAnxiety• StressStress• TensionTension

PainPain Pressure BreathingPressure Breathing HypoxiaHypoxia

HyperventilationHyperventilation

Subjective SymptomsSubjective Symptoms

DizzinessDizziness FaintnessFaintness Visual ProblemsVisual Problems TinglingTingling NauseaNausea Light HeadednessLight Headedness

Muscle TwitchingMuscle Twitching Cold, clammy skinCold, clammy skin Muscle TightnessMuscle Tightness PalenessPaleness UnconsciousnessUnconsciousness

Objective SignsObjective Signs

Hypoxic Hypoxia - Hyperventilation Hypoxic Hypoxia - Hyperventilation ComparisonComparison

SignsSigns HyperventilationHyperventilation HypoxiaHypoxia

OnsetOnset GradualGradual Varies with altitudeVaries with altitude

Muscle Muscle ActivityActivity

SpasmSpasm FlaccidFlaccid

Skin Skin AppearanceAppearance

Pale, ClammyPale, Clammy CyanosisCyanosis

TetanyTetany PresentPresent AbsentAbsent

DizzinessDizziness XX XX

EuphoriaEuphoria XX XX

FatigueFatigue XX XX

HeadacheHeadache XX XX

Poor JudgmentPoor Judgment XX XX

Light Light headinessheadiness

XX XX

TinglingTingling XX XX

Treatment for Treatment for HyperventilationHyperventilation

100% Oxygen100% Oxygen Return Rate and Return Rate and

Depth of Breathing to Depth of Breathing to NormalNormal

Check ConnectionsCheck Connections

Paper Bag MethodPaper Bag Method• Used at altitude where Used at altitude where

supplemental oxygen is supplemental oxygen is not required or needednot required or needed

Talk or sing to control Talk or sing to control the rate of breathingthe rate of breathing..

Other Physiological Affects of Other Physiological Affects of Altitude/Pressure ChangeAltitude/Pressure Change Decompression sicknessDecompression sickness

• Caused by the formation of Caused by the formation of nitrogen bubbles in the blood and nitrogen bubbles in the blood and tissues following a sudden drop in tissues following a sudden drop in the surrounding pressure, as when the surrounding pressure, as when ascending rapidly. ascending rapidly.

• Characterized by severe pains in Characterized by severe pains in the joints and chest, skin irritation, the joints and chest, skin irritation, cramps, and paralysiscramps, and paralysis

TreatmentTreatment• Decompression sickness is Decompression sickness is

a medical emergency, a medical emergency, respond appropriately.respond appropriately.

• NOTE: Time between scuba diving NOTE: Time between scuba diving on non-decompression stop dives on non-decompression stop dives and flying is 12 hours. The and flying is 12 hours. The minimum time between minimum time between decompression stop diving and decompression stop diving and flying is 24 hours.flying is 24 hours.

Other Physiological Affects of Other Physiological Affects of Altitude/Pressure ChangeAltitude/Pressure Change

Sinus/inner ear Sinus/inner ear blockageblockage• Caused by the differenceCaused by the difference in in

pressure from the middle pressure from the middle ear and the outside world, ear and the outside world, most likely due to a cold, most likely due to a cold, ear infection or a sore ear infection or a sore throat.throat.

• TreatmentTreatment On descent, level off and On descent, level off and

ValsalvaValsalva Reverse direction of Reverse direction of

pressure changepressure change Retry ValsalvaRetry Valsalva Use reduced rates of Use reduced rates of

descent and landdescent and land

The eustachian tube allows air pressure to equalize in the middle ear.

ConclusionConclusion

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

As a pilot you must be prepared for any As a pilot you must be prepared for any physiological situation that may arise.physiological situation that may arise.

You must be able to recognize the symptoms of You must be able to recognize the symptoms of Hypoxia and Hyperventilation as well as be able Hypoxia and Hyperventilation as well as be able to take the appropriate action in order to prevent to take the appropriate action in order to prevent conditions from getting worse.conditions from getting worse.

Physiological TrainingPhysiological Training

UNDAF Altitude Chamber

FAA Physiological Training

Highly recommendedHighly recommended Experience conditions Experience conditions

that can lead to that can lead to hypoxiahypoxia

Learn to recognize Learn to recognize hypoxiahypoxia

Learn about other Learn about other physiological physiological limitations when flyinglimitations when flying