Flight Physiology

Question 1

Boyle’s Law

Answer 1

As altitude increases, the atmospheric pressure decreases, and gas in an enclosed space will expand.

P1V1=P2V2

For every 1500 feet in altitude increase, about 5% change in atmosphere. ie - 1500 feet = .95 ATM 3000 ft = .90 ATM

Question 2

Charles Law

Answer 2

The relationship between temperature and volume is proportional to constant atmospheric pressure. As the temperature goes up, the volume of gas expands. As the temperature goes down, the volume of gas decreases.

For every 1000 feet ascended, temperature decrease 2 degrees celcius.
For every 150 meters, temperature decreases 1 degree celcius.

Wet lapse rate = 0.6 degrees celcius for every 100 meters of increase or decrease

Question 3

Gay Lussac’s Law

Answer 3

For a given mass and constant volume of a gas, the pressure exerted on the sides of its container is directly proportional to its absolute temperature.

Question 4

Dalton’s Law

Answer 4

The total pressure of a gas mixture is the sum of the partial pressures of all gases. In addition, it describes how pressure is exerted by gas at various altitudes and how that pressure affects the partial pressure of the said gas.

760mmgh x .21 = 159.6 mmgh of 02
Increasing Fi02 overcomes daltons law
18,000 ft = .5 ATM

Question 5

Henry’s Law

Answer 5

The amount of gas dissolved in a solution is directly proportional to the pressure exerted above the gas over the solution OR The amount of oxygen dissolved in capillary blood is directly proportional to the pressure of the oxygen over the capillary blood.

Increasing Pressure (NIIV, vapotherm)
Henry’s Law is the most important gas law per test questions

Question 6

Fick’s Law

Answer 6

The rate of diffusion of a gas across a permeable membrane is determined by the chemical nature of the membrane itself, the surface area of the membrane, the partial pressure gradient of the gas across the membrane, and the thickness of the membrane.

Increases surface tension
Adding PEEP

Question 7

Graham’s Law

Answer 7

The rate of diffusion of a gas is inversely proportional to the square root of its molecular weight. This means that diffusion will happen at a faster rate if the gas is thinner and at a slower rate if the gas is heavier.

**Higher concentrations to lower concentrations until equilibrium is reached. **

Question 8

Barotitis Media

Answer 8

Trapped air and fluids in the inner ear expanding as the eustachian tubes narrows as your ascent altitude. Extreme pain on descent. Only cavity problem with pain on descent.

Question 9

Barosinusitis

Answer 9

Sinus inflammation that prevents the equalization of pressure within the sinus cavities.

Pain on ascent

Question 10

Barobariatrauma

Answer 10

Nitrogen narcosis as a result of the affinity of nitrogen in relation to adipose tissue.

As we ascend, in morbidly obese patients nitrogen to attach to lipid stores.

High flow oxygen can help move nitrogen off of lipids.

Question 11

Bedside Pa02 Calculation

Answer 11

(700 torr x Fi02) -50

Question 12

Stressor Acronym

Answer 12

Drugs
Exhaustion
Alcohol
Tobacco
Hypoglycemia

Question 13

Stages of Hypoxia

Answer 13

Indifferent - Night vision reduced at or above 4000 ft 0-10
Compensatory - headache 10-15
Disturbance - blurred vision, congitive decline 15-20
Critical - Dead 20-25

Question 14

Explosive Decompression Question Rule

Answer 14

Time of useful conciousness will be single digit seconds. Most likely the least amount of time available in answers.