Types of Hypoxia hypoxic hypoxia hypemic hypoxia stagnant hypoxia histotoxic hypoxia

Hypoxic Hypoxia (Altitude Hypoxia) A deficiency in Alveolar oxygen exchange Reduced O2 in the lungs (high altitude) Red blood cells Body tissue

Hypoxic Hypoxia Most common type of Hypoxia occur in aviation. Hypoxic hypoxia occurs when not enough oxygen is in the air or when decreasing atmospheric pressures prevent the diffusion of O2 from the lungs to the bloodstream. This is the type that is most likely to be encountered at altitude. The partial pressure of oxygen as it is presented to the blood within the lungs is too low to effectively carry and transfer enough oxygen to the cells of the tissues. Hypoxic hypoxia occurs when not enough oxygen is in the air or when decreasing atmospheric pressures prevent the diffusion of O2 from the lungs to the bloodstream. The partial pressure of oxygen as it is presented to the blood within the lungs is too low to effectively carry and transfer enough oxygen to the cells of the tissues.

Hypoxic Hypoxia Can be resulted from: Altitude exposure Strangulation (compression of air passage cause the respiration arrest) Other: Failure of oxygen system in aircraft Improper use of equipment Failure of depressurization system

Stagnant Hypoxia Occurs at circulatory level. A condition that interferes within the normal circulation of blood arriving at the cells. An arm or leg going to sleep because the blood flow has accidentally been shut off is one form of stagnant hypoxia.

Stagnant Hypoxia Can occur as the result of: G forces from maneuvers (mostly aerobatic aircraft) Disease of the blood vessels Cardiac (Heart) Arrest Shock Exposure to Cold Sudden change in posture

Stagnant Hypoxia The g-force, on something is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces. Accelerations not produced by gravity are termed proper accelerations, and cause stresses and strains on objects. Because of these strains, large g-forces may be destructive.

Where can we find hemoglobin? What is the function of hemoglobin? Think out of the box!! What is hemoglobin? Where can we find hemoglobin? What is the function of hemoglobin? What are the risks if the amount of hemoglobin inside our body is low?

Hypemic Hypoxia Occurs at blood level. An oxygen deficiency due to reduction in the oxygen carrying capacity of the blood (Low Hemoglobin)

Hypemic Hypoxia Caused by: Anemia (A deficiency of red blood cells) Bleeding Taking some prescription drug. *Blood donation Other: Smoking ; cabin contamination with engine exhaust fume Carbon Monoxide interferes with oxygen binding to the blood

Hypemic Hypoxia *Blood Donation: Symptoms of hypoxia at lower altitudes Most airlines: No flight for 72 hours after donation of whole blood No flight for 12 hours after donation of plasma

Histotoxic Hypoxia Occurs at cell level Interferes with the normal utilization of oxygen into the cells. plenty of oxygen is being transported to the cells that need it, but they are unable to make use of it. Tissue cells are poisoned and unable to use oxygen Caused by Alcohol and Drug

Why Important to recognize? If hypoxia is prolonged, serious problems develop with ultimate death. In extreme cases (prior to death), some brain cells are actually killed, and they cannot be regenerated. The single most dangerous characteristic of hypoxia is that if the crewmember is hypoxic and engrossed (complete attention) in flight duties, the pilot might not even notice the impairment.

Indifferent Stage Compensatory stage Disturbance stage Critical Stage Stage of Hypoxia Indifferent Stage Compensatory stage Disturbance stage Critical Stage

Stage of Hypoxia INDIFFERENT STAGE This is the mildest stage of hypoxia. People are not generally aware of the effects of hypoxia at this stage. The primary is effect on the eye such as loss of night vision or color vision. The only significant effect of mild hypoxia in this stage is that night vision deteriorates at about 4,000 feet. The retina of the eye and the central nervous system have a great requirement for oxygen. To begin compensating for this, the heart rate and breathing rate increase at about 4000 feet to improve circulation to brain and heart. Decrease of visual sensitivity of up to 28% at 10,000 feet, varying among individuals. NOTE: Symptoms of hypoxia become evident at 87% hemoglobin saturation.

Stage of Hypoxia COMPENSATORY STAGE The circulatory system, and to a lesser degree, the respiratory system, provide some defense against hypoxia in this stage. Symptoms: poor judgement, drowsiness(sleepy state) impaired efficiency. Pulse rate increases circulation rate increases In healthy people, this stage may occur at altitudes between 10,000 and 15,000 feet. The body generally has the ability to stave off further effects of hypoxia by increasing the rate and depth of ventilation and cardiac output. Arterial oxygen saturations during this phase are typically between 80 and 90 percent. The circulatory system, and to a lesser degree, the respiratory system, provide some defense against hypoxia in this stage.

Stage of Hypoxia DISTURBANCE STAGE In this stage the physiological compensations do not provide adequate oxygen for the tissues. Chance of recovery greatly diminished. Symptoms: impaired in flight control, handwriting, speech, coordination, cyanosis, poor judgments and difficulty with simple tasks          CRITICAL STAGE Unconsciousness (e.g: blackout, faint) In the critical stage consciousness is lost. Death follows shortly. In this stage, the physiological responses can no longer compensate for the O2 deficiency in the organ systems of the body. Symptoms: Hypoxia symptoms become severe at this stage. Sensory - Vision - peripheral and central vision are impaired and visual acuity is diminished. - Touch and pain - diminished or lost. Hearing - one of the last senses to be lost. Mental - intellectual impairment is an early sign that often prevents an individual from recognizing disabilities. - Memory - Judgment and reliability - Understanding - Decision making/problem solving Personality - may be a release of basic personality traits and emotions as with alcohol intoxication. - Euphoria - Aggressiveness - Overconfidence - Depression Performance (psychomotor functions): Coordination, flight control, speech and handwriting suffer

Sign of Hypoxia Increase in depth and rate of breathing Cyanosis (A blurry effect of the skin, most noticeable on the lips and the fingernail) Delayed in reaction time Poor Judgment

Symptoms of hypoxia Air Hunger ( a feeling not enough breathable air) Feeling of fearful or anxiety (nervousness) Mental confusion Fatigue Nausea (just before vomit) Headache Dizziness Hot and cold flashes Visual Impairment (colour vision, night vision, blurred)

How to prevent?? Reduce tolerance to altitude (descends) Don’t fly to high altitude By enriching the inspired air with oxygen from an appropriate oxygen system (Oxygen Tank & Mask) By maintaining a comfortable, safe cabin pressure altitude (Cabin Pressurization)

How to prevent?? Avoid alcohol and smoking Healthy Diet Good physical condition Lower altitudes Avoid temperature extremes Slower Climb rates

Corrective action Once the symptoms/sign are identified, the corrective action must be taken (based on FAR): Wear oxygen mask Turn on Oxygen Make sure all connection secure Slow down your breath rate Descend to altitude where supplementary oxygen no longer required.

Effective Performance Time (EPT) EPT is the period of time that a pilot has from the time oxygen become less available until the time when he or she loses the ability to recognize and take action EPT is the time a crewmember has from the interruption of the O2 supply to the time when the ability to take corrective action is lost. What does it mean?

Effective Performance Time (EPT) If someone goes beyond EPT, then he or she isn’t even aware of the problem and will not take corrective action The keyword is EFFECTIVE or USEFUL (He or she might be conscious but not making expected useful or effective decision).

Conclusion The danger of hypoxia is that the pilot is probably unsuspecting that he/she is hypoxic. The key to flying safe at high altitude is to recognize: The conditions under which you could be hypoxic. The physical and mental symptoms that indicate you are hypoxic. When a crewmate is susceptible to hypoxia in those conditions.