ALTITUDE PHYSIOLOGY. Physiological Zones of the Atmosphere. Composition of the Air AIR ATTENDANTS COURSE. Sea Level Pressure

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AIR ATTENDANTS COURSE ALTITUDE PHYSIOLOGY Physical Divisions of the Atmosphere 1200 miles 600 miles EXOSPHERE Physiological Zones of the Atmosphere 50 miles

FEET TROPOSPHERE Sea level to flight level 300-600 depending on temperature, latitude and season.

1 AIR ATTENDANTS COURSE ALTITUDE PHYSIOLOGY Physical Divisions of the Atmosphere 1200 miles 600 miles EXOSPHERE Physiological Zones of the Atmosphere 50 miles IONOSPHERE SPACE EQUIVALENT ZONE: 50,000 feet and above 63,000 ft STRATOSPHERE DEFICIENT ZONE: 10,000 to 50,000 feet Tropopause 18,000 ft MOUNT EVEREST 29,028 FEET TROPOSPHERE Sea level to flight level depending on temperature, latitude and season. EFFICIENT ZONE: Sea level to 10,000 feet Composition of the Air Sea Level Pressure 78 Percent Nitrogen N2 21 Percent Oxygen 1 Percent Other.03 percent CO PSI 760 mm Hg OR in. Hg lbs Scale Barometer / Altimeter 1 1

PERCENT COMPOSITION OF THE ATMOSPHERE REMAINS CONSTANT BUT PRESSURE DECREASES WITH ALTITUDE SIGNIFICANT PRESSURE ALTITUDES ALTITUDE PRESSURE FEET mm/hg ATMOSPHERES 0 760 1 18,000 380 1/2 34,000 190

2 PERCENT COMPOSITION OF THE ATMOSPHERE REMAINS CONSTANT BUT PRESSURE DECREASES WITH ALTITUDE SIGNIFICANT PRESSURE ALTITUDES ALTITUDE PRESSURE FEET mm/hg ATMOSPHERES , /2 34, /4 48, /8 63, / mm Hg 21% O 2 78% N mm/hg Partial Pressure (Dalton s Law) (Dalton s Law) The pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each gas in the mixture. Pt = P 1 P 2... Pn FUNCTIONS OF THE CIRCULATORY SYSTEM Oxygen and nutrient (fuel) transport to the cells. Components of the Circulatory System Transport of metabolic waste products to organ removal sites. Assists in temperature regulation. 2 2

Blood transport of O 2 and CO 2 CO2 O2 Plasma CO2 FUNCTIONS OF THE RESPIRATORY SYSTEM Intake of Oxygen [O 2 ] Removal of Carbon Dioxide [CO 2 ] O2 CO2 O2 Maintenance of body heat balance hemoglobin

Nasal/Oral pharynx Trachea Bronchi Alveoli Active Phase INHALATION Passive Phase EXHALATION Law of Gaseous Diffusion Gas molecules of higher pressure move in the direction of gas molecules of a lower

3 Blood transport of O 2 and CO 2 CO2 O2 Plasma CO2 FUNCTIONS OF THE RESPIRATORY SYSTEM Intake of Oxygen [O 2 ] Removal of Carbon Dioxide [CO 2 ] O2 CO2 O2 Maintenance of body heat balance hemoglobin molecule O2 molecule Maintenance of body acid base balance [ph] Red Blood Cell Breathing in Phases of Respiration Breathing out COMPONENTS OF THE RESPIRATORY SYSTEM Bronchiole Alveolar Ducts Nasal/Oral pharynx Trachea Bronchi Alveoli Active Phase INHALATION Passive Phase EXHALATION Law of Gaseous Diffusion Gas molecules of higher pressure move in the direction of gas molecules of a lower pressure PO 2 = 100mmHg PO 2 = 40mmHg Blood Gas Exchange CO 2 PCO 2 = 46 mm PO 2 = 1-60 mm PCO 2 = 46 mm Venous Capillary Hemoglobin Saturation 75% Tissue PO 2 = 40 mm Alveoli PO 2 = 100 mm O 2 PCO 2 = 40 mm O 2 CO 2 O 2 PO 2 = 70 mmhg PO 2 = 70 mmhg O 2 PCO 2 = 40 mm PO 2 = 100 mm Arterial Capillary Hemoglobin Saturation 98% 3 3

4 Oxygen transport in the blood: dependent on the partial pressure of oxygen. po 2 Correction of Altitude, Alveolar O 2, Hb saturation ambient air ALTITUDE BAROMETRIC ALVEOLAR HEMOGLOBIN (FEET) PRESSURE OXYGEN SATURATION (mmhg) ( PAO 2 ) % (Hb) Sea level , , , , , Correction of Altitude, Alveolar O 2, Hb saturation % Oxygen ALTITUDE BAROMETRIC ALVEOLAR HEMOGLOBIN (FEET) PRESSURE OXYGEN SATURATION (mmhg) ( PAO 2 ) % (Hb) Sea level , , , , , Hypoxia State of oxygen [O 2 ] deficiency in the blood cells and tissues sufficient to cause impairment of function. Types of Hypoxia Hypemic Stagnant Histotoxic Hypoxic A deficiency in Alveolar oxygen exchange Hypoxic Hypoxia Reduced po 2 in the lungs (high altitude) Red blood cells Body tissue 4 4

5 Hypemic Hypoxia An oxygen deficiency due to reduction in the oxygen carrying capacity of the blood Adequate oxygen Blood moving slowly Stagnant Hypoxia Reduced blood flow Red blood cells not replenishing tissue needs fast enough Adequate oxygen Poisoned tissue Histotoxic Hypoxia Inability of the cell to accept or use oxygen Red blood cells retain oxygen Hypoxia Symptoms what you feel (subjective) Air hunger Apprehension Fatigue Nausea Headache Dizziness Denial Hot & Cold Flashes Euphoria Belligerence Blurred Vision Numbness Tingling Hypoxia Signs what we see in you (objective) Hyperventilation Cyanosis Mental confusion Poor Judgment Lack of muscle coordination Stages of Hypoxia Indifferent Stage Compensatory Stage Disturbance Stage Critical Stage 5 5

Altitudes: Indifferent Stage Air: 0-10,000 feet 100% O 2 : 34,000-39,000 feet Symptoms: decrease in night vision @ 4000 feet acuity color perception Altitudes: Compensatory Stage Air: 10,000-15,000

6 Altitudes: Indifferent Stage Air: 0-10,000 feet 100% O 2 : 34,000-39,000 feet Symptoms: decrease in night 4000 feet acuity color perception Altitudes: Compensatory Stage Air: 10,000-15,000 feet 100% O 2 : 39,000-42,000 feet Symptoms: impaired efficiency, drowsiness, poor judgment and decreased coordination CAUTION!!!! Failure to recognize your signs and symptoms may result in an aircraft mishap. Disturbance Stage Altitudes Air: 15,000-20,000 FEET 100% O 2 : 42,000-44,800 FEET Disturbance Stage symptoms Time of Oxygen depletion Memory Judgment Reliability Understanding Coordination Flight Control Speech Handwriting 1 Minute 2 Minutes 3 Minutes 4 Minutes 5 Minutes 6 Minutes Put Back on Oxygen 6 6

Disturbance Stage Signs Hyperventilation Cyanosis Critical Stage Altitudes Air:

consciousness, convulsions and death Factors modifying hypoxia symptoms Pressure

Individual factors Physical fitness Self-imposed stresses DEATH Drugs Exhaustion

ALCOHOL Expected performance time for a crew member flying in a pressurized

7 Disturbance Stage Signs Hyperventilation Cyanosis Critical Stage Altitudes Air: 20,000 feet and above 100% O 2 : 44,800 feet and above Signs: loss of consciousness, convulsions and death Factors modifying hypoxia symptoms Pressure altitude Rate of ascent Time at altitude Temperature Physical activity Individual factors Physical fitness Self-imposed stresses DEATH Drugs Exhaustion Alcohol Tobacco Hypoglycemia keep self imposed stresses out of the aircraft ALCOHOL Expected performance time for a crew member flying in a pressurized cabin is reduced approximately one-half following loss of pressurization such as in a: RD Rapid Decompression 7 7

8 Expected Performance Times FL 430 & above 9-12 seconds FL seconds FL seconds FL minutes FL /2-3 minutes Hypoxia Prevention Limit time at altitude 100% O 2 FL minutes FL minutes FL minutes Hypoxia Treatment 100% O 2 Descend to a safe altitude Hyperventilation (definition) An excessive rate and depth of respiration leading to the abnormal loss of CO 2 from the blood. Hyperventilation (causes) Emotional (fear, anxiety, apprehension) Pressure breathing Hypoxia Hyperventilation Symptoms tingling sensations muscle spasms hot and cold sensations visual impairment dizziness unconsciousness 8 8

Hyperventilation reason for symptoms: loss of carbon dioxide [CO 2 ] shift in ph balance Hyperventilation significance incapacitation of an otherwise outstanding, healthy air crewmember confusion

9 Hyperventilation reason for symptoms: loss of carbon dioxide [CO 2 ] shift in ph balance Hyperventilation significance incapacitation of an otherwise outstanding, healthy air crewmember confusion with hypoxia Hyperventilation (distinguishing factors) Hyperventilation (corrective actions) above 10,000 feet possible hypoxia below 10,000 feet probably hyperventilation Don t Panic Control your breathing Check your oxygen equipment - it may be hypoxia Dysbarism Boyle s Law Syndrome resulting from the effects, excluding hypoxia, of a pressure differential between the ambient barometric pressure and the pressure of gases within the body. The volume of a gas is inversely proportional to its pressure; temperature remaining constant. 9 9

10 10 6.0X Gas Expansion 43,000 9.5X Gas Expansion (prevention of gas pain) 4.0X 34,000 5.0X 2.5X 25,000 3.0X 1.8X 18,000 2.

Anatomy of the Ear Pressure Effect Semicircular canal Cochlea Auditory nerve Tympanic Membrane External Ear Middle Ear Cavity Atmospheric Pressure Clear Eustachian Tube Ear drum

10 X Gas Expansion 43, X Gas Expansion (prevention of gas pain) 4.0X 34, X 2.5X 25, X 1.8X 18, X Watch your diet, don t eat too fast Avoid soda and large amounts of water just prior to going to altitude Don t chew gum during ascent Keep regular bowel habits; eat your fiber Anatomy of the Ear Pressure Effect Semicircular canal Cochlea Auditory nerve Tympanic Membrane External Ear Middle Ear Cavity Atmospheric Pressure Clear Eustachian Tube Ear drum External ear Middle ear Eustachian tube Opening to throat Middle Ear Cavity Tympanic Membrane External Ear Eustachian Tube Blocked / Infected Atmospheric Pressure Ear Block Tympanic membrane, (ear drum), normal Tympanic membrane, (ear drum), inflamed

11 11 The Sinuses Tympanic membrane, (ear drum), infected Frontal Ethmoid Maxillary Sphenoid Treatment of an Sinus/Ear Block Stop the descent of the aircraft and attempt to clear by valsalva.

11 11 11 The Sinuses Tympanic membrane, (ear drum), infected Frontal Ethmoid Maxillary Sphenoid Treatment of an Sinus/Ear Block Stop the descent of the aircraft and attempt to clear by valsalva. If unable to clear, climb back to altitude until clear by pressure or valsalva. Descend slowly and clear ear frequently during descent. Barodontalgia Tooth pain due to: Gum abscess: dull pain on ascent Inflamed pulp: sharp pain on ascent Inflamed maxillary sinus: pain primarily on descent TREATMENT of Barodontaliga Descend aircraft/chamber to sea level. Seek dental help Decompression Sickness (evolved gas dysbarism) Results due to the reduction in atmospheric pressure. As pressure decreases, gases dissolved in body fluids are released as bubbles.

12 12 12 Henry s Law Evolved Gas Disorders The amount of gas dissolved in solution is directly proportional to the pressure of the gas over the solution. The Bends N2 bubbles become trapped in the joints. Onset is mild, but eventually painful! Evolved Gas Disorders Evolved Gas Disorders Paresthesia N2 bubbles form along nerve tracts. Tingling and itchy sensation and possibly a mottled red rash. The Chokes N2 bubbles block smaller pulmonary vessels. Burning sensation in sternum. Uncontrollable desire to cough. Sense of suffocation ensues. Evolved Gas Disorders Evolved gas factors CNS N2 bubbles affect spinal cord. Visual disturbances, paralysis, one sided tingling. Rate of ascent Altitude Body fat content Age Exercise Duration of exposure Repeated exposure

13 13 120 100 80 60 40 20 0 Decompression Sickness Denitrogenation 0 1 2 3 4 5 TIME IN HOURS prevention Denitrogenation Maintain cabin pressurization Decompression Sickness treatment Descend 100%

Altitude Restrictions and Oxygen Requirements Altitude Restrictions and Oxygen Requirements Unpressurized 14,000 Supplemental Oxygen Required 25,000 30 Min Total 12,000 10,000 Crew O2 masks readily

13 Decompression Sickness Denitrogenation TIME IN HOURS prevention Denitrogenation Maintain cabin pressurization Decompression Sickness treatment Descend 100% Oxygen Land at nearest location where qualified medical assistance is available. Compression greater than 1 atmosphere (absolute). Altitude Restrictions and Oxygen Requirements Altitude Restrictions and Oxygen Requirements Unpressurized 14,000 Supplemental Oxygen Required 25, Min Total 12,000 10,000 Crew O2 masks readily available 1 Hour Total Pressurized If pressurization is lost above 14,000, an immediate descent will be made to a cabin pressure altitude of 10,000 or below. Then unpressurized restrictions apply 10 Min Supply of O2 for all occupants 14,000 10,000 Maintain Cabin PA at or below 10,000 Flight Restrictions Due to Exogenous Factors Flying duty is prohibited for 24 hours after SCUBA diving Aircrew members will not be regular blood donors. After blood donation, aircrew members will be restricted from flying for 72 hours Conclusion The challenge is NOT to be innovative in a crisis. The challenge is to be well-trained and well-disciplined enough to FOLLOW THE RULES! Performance of flying duty is prohibited for 12 hours after any altitude chamber flight

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American College of Occupational and Preventive Medicine 2011 Annual Meeting, Orlando, Florida, November 2, 2011

American College of Occupational and Preventive Medicine 2011 Annual Meeting, Orlando, Florida, November 2, 2011 Administrative Information Risk Assessment: Low AEROSPACE/ OCCUPATIONAL MEDICINE BAROMETRIC CONCERNS Dr. John Campbell, MFS Environmental Considerations: None Safety Considerations: None Evaluation: 50