Stresses of Transport• Hypoxia• Trapped Air• Thermal changes• Decreased Humidity• Noise• Vibration• Fatigue• Gravitational,

acceleration/deceleration forces

Hypoxia

An oxygen deficiency sufficient to cause an impairment of function

• Causes– Inadequate supply of oxygen– Inadequate oxygen transport

capability– Inability of body to use oxygen

Stages of Hypoxia• Indifferent Stage

– Physiologic zone: 0 – 10 K feet– Increased HR and RR– Decrease in night vision @ around 5 K

Stages of Hypoxia

• Compensatory Stage– 10 K – 15 K feet– Increased HR, RR, BP, Respiration

Depth– Drowsiness– Poor judgement– Impaired coordination– Impaired efficiency

Stages of Hypoxia

• Disturbance Stage– 15 K – 20 K feet– Characterized by

• Dizziness, sleepiness, tunnel vision, cyanosis, slowed thinking and decreased muscle coordination.

– Which can cause…• Impaired flight control• Impaired handwriting• Impaired speech• Decreased coordination

Stages of Hypoxia

• Critical Stage– 20 K - 30 K feet– Mental confusion and incapacitation– Unconsciousness– Circulatory failure– Cardiovascular collapse– Death

Types of Hypoxia• Hypoxic Hypoxia• Anemic Hypoxia• Stagnant Hypoxia• Histotoxic Hypoxia

Hypoxic Hypoxia

• Deficiency in alveolar oxygen exchange.

• Causes– Reduction of pO2 in inspired air

– Ineffective gas exchange in an area of the lung

• Result– Inadequate oxygen supply in arterial

blood

Hypoxic Hypoxia

Altitude Pressure Oxygen

sea level 760mmHg 160mmHg

1000 ft. 732 132 8000 ft. 564 11818000 ft. 380 8034000 ft. 187 39

• Reference Protocol:– Atmospheric Pressure, Limits for Specific Disease

Processes

Hypoxic Hypoxia

• Treatment– Supplemental 02– Altitude restriction– BIPAP– Advanced airway management– Fix problem

Anemic Hypoxia

• Reduction of 02 carrying capacity – Decrease in circulating Hgb– Reduction of functional / avail Hgb

• Treatment– Maximize available 02– Consider transfusion

Stagnant Hypoxia

• 02 deficiency secondary to poor circulation– Heart failure– Hypovolemia– Shock (any source)

• Treatment– Maximize 02 supply– Maximize 02 delivery

• Consider volume• Consider pump

Histotoxic Hypoxia

• Inability to utilize 02 at cellular level– “Poisoned tissue”

• Causes– Sepsis– Alcohol– Cyanide– Carbon monoxide

• Treatment– Cause specific