MANDATORY CPAP exam 2 info Flashcards
Daltons Law
total atmospheric pressure is equal to the sum of the partial pressure of all the gases
Why can’t you breath as easy at higher elevation?
The O2 levels are still the same, however, the decrease in atmospheric pressure is what makes it harder to breath.
Diffusion
Random movement of gases across the AC membrane
PA02 (O2 in the alveoli) pressure
100mmHg
How long does it normally take blood to pass through the capillary while someone is at rest?
0.75 sec
On spontaneous inspiration, what pressures change?
Both the intra alveolar and intra pleural pressures DECREASE
Pleural pressure change in normal breathing vs deep inspiration
Normal: pleural pressure changes 3-6cmH2O(2-4mmHg)
Deep: pleural pressure drops to -50cmH2O
Pleural pressur change in forced exhalation
+70 to +100cmH2O
Lung Compliance on ventilator equation
Tidal Volume/ (plat-PEEP)
Surface tension makes the alveoli stay open or closed?
Surface tension wants to pull the alveolus closed while the surfactant helps decrease this force.
Normal dead space/tidal volume ratio
25%-35%
Best position for increasing ventilation
Fowler’s (sitting up)
Bohr equation and what it solves
Paco Peco formula and it helps find the dead space ratio
If the RAW is increased, what will the ventilatory pattern look like?
decreased RR with increased tidal volume
If lung compliance is decreased what will the ventilatory pattern look like?
increased RR with lower tidal volume
Normal RAW range
0.5-1.5cmH20/L/sec
Normal lung compliance
50 to 100mL/cmH20
If you decrease minute ventilation by 50% what will happen to the CO2
CO2 will double
In diffusion, the PaO2 level reflects what?
shows
In diffusion, the PaCO2 level reflects what?
ventilation
What happens to diffusion rates during exercise?
Blood passes through the capillary at a quicker rate than the normal 0.75 sec, but its okay because it only takes the gas 0.25 sec to diffuse.
Which gas is used during the DLCO test?
Carbon monoxide, and its used because it diffuses across the AC membrane 200 times faster than O2 and CO2
The pressure of water vapor is always what?
PH2O is always 47mmHg in the venous, arterial, and lung
PvCO2 level
46mmHg
PACO2 level
40mmHg
under normal conditions, the diffusion of oxygen is perfusion limited or diffusion limited
normally O2 is perfusion limited
The DLCO is the primary test to diagnose what disorder?
Emphysema
Example of diffusion limited
Emphysema
Ficks Law
diffusion rate directly proportional to surface area
water vapor pressure
Always 47mmHg
Alveolar minute ventilation
(VT-VD) x RR
When can static compliance be obtained?
During a breath hold, which is found by plateau-PEEP (PEEP is also called baseline)
Poiseuille Law- radius vs flow
If a tubes radius increases by 1/2, the flow will increase 16 times. Has a positive correlation*
Poiseuille Law-radius vs pressure
decrease radius by 1/2, pressure required would be 16 times more to maintain the same flow
