What does Fick’s Law state?
The volume of gas diffusing per minute across a membrane is directly proportional to the membrane area, diffusion coefficient of the gas, and the partial pressure difference of the gas and diffusion of the gas is inverse to the membrane thickness (Vgas=AD(P1-P2)/T)
What is hypercapnea?
Excessive carbon dioxide in the blood
What is hypopnea?
Diminished depth and rate of respiration
What is hyperpnea?
Abnormal increase in depth and rate or respiration
What occurs when a Type I pneumocytes is damaged?
It is replace by a Type II which then differentiates into a Type I
What is the purpose of the Pore of Kahn?
Connects alveoli to allow movement from one alveoli to another
How do alveoli grow as we do?
Grow in number til age 8 and only decrease in size from there
Normal tidal volume:
500mL
Anatomic dead space volume:
150mL
Amount that make it to alveoli:
350mL
Difference between anatomic and alveolar dead space?
Anatomic: air does not touch alveoli for gas exchange
Alveolar: alveoli are not exchanging gas (no perfusion)
Is V/Q greater or less than 1 in the apex?
Greater (nondependent region)
Is V/Q greater or less than 1 in the base?
Less (dependent region)
Is the base or the apex more compliant?
Base (apex is already expanded because gravity)
What occurs to the V/Q ratio in patients with a emphysema?
It decreases because ventilation decreases but blood flow remains normal
What is the ultimate goal of ventilation?
To keep alveolar respiratory gas partial pressures as close to atmospheric as possible
What is the respiratory duty cycle?
One respiratory cycle of inspiration and expiration
What costs more energy inspiration or expiration?
Inspiration
What occurs to Tv as a diseased patient increases frequency of breathing?
Tv decreases
What is the most energetically favorable breathing pattern for pulmonary fibrosis?
Shallow and rapid breathing (increased Tv means increase ATP)
How to calculate mechanical ventilation for patients without pre-existing lung disease?
8mL/kg x 12 times a minute
How to calculate mechanical ventilation for patients with chronic pre-existing lung disease?
10-10 rule 10mL/kg x 10 a minute
How to calculate mechanical ventilation for patients with acute lung disease?
6mL/kg x 10-12 times a minute
How many kg are in a lb?
.454 kg/lb
What effect does resistance have on frequency of breathing?
Increased resistance leads to increased frequency
