Airway Resistance Flashcards
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Reynold’s number
Predicts whether flow will be laminar or turbulent
Formula for Reynolds number
Vpd/n
Hagen poiselle eqn
/_\P.pie.r4/8.l.u
Change in pressure equals
Flow x resistance
Therefore resistance varies inversely with fourth power of radius
Which airways have the highest resistance
Medium sized airways
Greatest resistance in?
Upper airways, first 7 generations
In regulation of airway diameter, parasympathetic innervation…?
Mediates bronchoconztriction
Sympathetic innervation?
Mediates bronchodilation,
Beta 2 adregenic receptors
Beta 2 agonists eg salbutamol/ salmeterol
Epinephrine
Why you should apply selective beta blockers to asthmatic pstirnyd bc it can block beta 2 receptors will will block respiratory airways
Histamine in regulation of airways works how?
H1 stimulation leads to bronchoconstrivyion
H2 stilumayion leads to bronchodilation
You should not administer beta 2 blockers to asth
Density of gas has no effect on resistance when airflow is..
Laminar
Patients with upper airway obstruction have more
Turbulence than laminar flow
Heliox useful than regular air because it has low density and since density is important in turbulent flow and turbulent flow in upper airway extraction
Volume flow rate equals
Cross sectional area × velocity
Area increases down tracheobronvhial trea. Velocity therefore drops since volume glow rate is nearly constant
At generation 16/17 gas movement is by
Diffusion(terminal bronchioles and alveoli)
Compliance is
Change is lung volume per unit pressure