FP-C #4 Flashcards by Ben McCarlson

Hypoxia between 0 and 10,000 ft

Indifferent stage

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Define: Hypemic hypoxia

The type of hypoxia characterized by an inability to carry oxygen on the red blood cell despite its abundance of oxygen

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Mneumonic: Dalton’s law

“Dalton’s gang” - on the ground, the molecules are ganged up

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Define: Dalton’s law

Total pressure of a gas mixture is the sum of the individual pressures

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Define: Barometric pressure

Direct result of the weight of the air and related to air density

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The three physiological zones of the atmosphere

Physiologic zone, physiologically deficient zone, space equivalent zone

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How high above sea level the atmosphere extends

348 miles (the edge of space)

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Define: Henry’s law

The amount of gas in solution varies directly with partial pressure of a gas over the solution

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Define: Charles’ law

Volume and temperature are proportional at constant pressure - as air heats up, gas expands

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Define: Time of useful consciousness (TUC)

Period between a person’s sudden deprivation of oxygen at a given altitude and the onset of physical or mental impairment to the point where deliberate function is lost

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Temperature variance in the troposphere

62°F to -68.8°F

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This is one of the earliest sign of hypoxia in a flight paramedic or flight nurse

Impaired judgment

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Concept: Henry’s law

As the pressure over a gas decreases, or gas escapes from the solution (ex: opening a soda can)

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Define: Fick’s law

States the rate of diffusion of a gas is proportional to the difference in partial pressure, proportional to the area of the membrane, inversely proportional to the thickness of the membrane

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EPT at TUC depend on these 7 factors

Individual tolerance, method of hypoxia, environment before hypoxia, amount of exertion undertaken, percent of oxygen prior to hypoxia, speed of cabin depressurization, higher altitude acclimatization

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An alternative name for Dalton’s law

The law of partial pressures

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Trapped gas in the chest will expand approximately this much at 18,000 feet

Twice it’s original size

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Define: Stagnant hypoxia

The type of hypoxia that occurs when there is a failure to transport oxygenated blood

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Boyle’s law

Inverse proportion of volume and pressure - as volume increases pressure decreases

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The percent composition that nitrogen accounts for in the atmosphere

78%

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This can happen to a pneumothorax at altitude

Pneumothorax can become tension pneumothorax

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Effects: Indifferent stage of hypoxia

Night vision deterioration (5000 feet), ECG changes (5000 feet), tachycardia, slight increase in alveolar ventilation

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Altitude will usually not become significant until this altitude

3000 feet

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Most people (except those with significant respiratory disorders) tolerate altitudes of ____

5000 feet

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The densest portion of the atmosphere

Troposphere

Define: Gay-Lussac's law

States there is a correlation between pressure and temperature with volume is close

Properties: Physiologic zone

Sea level--\> 10,000ft - barometric pressure of 760 mmHg--\> 523 mmHg

Define: Graham's law

The rate at which a gas moves through a pore is inversely related to the square root of the mass of one mole of its molecules

The four stages of hypoxia (related to altitude)

Indifferent stage, compensatory stage, disturbance stage, critical stage

Poor blood flow - as in CHF and in acute MIs

Causes: Hypemic hypoxia

Blood loss, anemia, excessive smoking, carbon monoxide, sickle cell disease

Below ___ feet, unhealthy people can experience significant side effects

below 10,000 feet

Define: Histotoxic hypoxia

A type of hypoxia characterized by a cell's inability to adequately use oxygen

These devices are considered unreliable and IV pumps should be used instead while at altitude

Dial-a-flow

The first two layers of the atmosphere

Troposphere and tropopause

Application of Dalton's law to critical care

Supplemental oxygen will be required typically at about 5000 feet in sick patients

Trapped gas in the chest will expand approximately this much when going from sea level to 8000 feet

35%

The altitude that the compensatory stage of hypoxia is experienced while on 100% oxygen

39 to 42,000 feet

Reduction of hemoglobin by half reduces the body's transport ability by \_\_\_

Half

The percent composition that argon accounts for in the atmosphere

0.93%

This is the flight level that FAR Part 135 specifies commercial pilots must begin using supplemental oxygen

Above 10,000 ft

These three gases make up 99% of the atmosphere

Nitrogen, oxygen, argon

Mnemonic for Charles' Law

C for Charles, C for Celsius (of course, Celsius temperature)

Oxygen saturation range: Compensatory stage of hypoxia

87 to 80%

You should do this with nasogastric or orogastric tubes frequently while at altitude

Frequently vent

Locations in the body where gases can be trapped and expand with altitude

Thorax, middle ear, sinuses, stomach, intestines

The four types of hypoxia

Hypoxic hypoxia, histotoxic hypoxia, stagnant hypoxia, hypemic hypoxia

The altitude range where endotracheal tube cuffs will double in size

5000 to 10,000 feet

At altitude, increases in flow rate of fluids in ___ \_\_\_ occurs because of an inability for the bottle to expand or contract

Glass bottles

Mnemonic: Boyle's law

Boil very prudently

Level where night vision impairment occurs without supplemental oxygen

5000 feet

Causes: Histotoxic hypoxia

Poisoning (carbon monoxide, cyanide)

This is the main medical hazard in flight aviation

Hypoxia

Define: Effective performance time (EPT)

The limited timeframe during which a person can't function without an adequate level of oxygen

The depth of the troposphere

Sea level to 26,400 feet over the poles, sea level to 52,800 feet over the equator

Causes: Hypoxic hypoxic

Lung disease, airway obstruction, low oxygen delivery, decreased altitude

Properties: Space equivalent zone

Extends beyond 50,000 feet to 120 miles, 100% supplemental oxygen required, requires pressure suits and sealed cabins

Patients with an open skull fracture are at risk for \_\_

Pneumocephalus

Application of Henry's law in critical care

Ascending for a dive too fast resulting in decompression sickness

Define: Hypoxic hypoxia

A type of hypoxia characterized by lack of oxygen entering the blood - formulation or reduction in PO2

The stage of hypoxia experienced at 10 to 15,000 feet

Compensatory stage

Oxygen saturation range: Indifferent stage

98-87%

Finding: High venous oxygen concentration

Confirms histotoxic hypoxia

Concept: Gay-Lussac's law

As you go up in altitude, the pressure is lower

Properties: Deficient Zone

1: Barometric pressure decreases to levels that will result in hypoxic hypoxia