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O2 from LUNGS to BLOOD and CO2 from BLOOD to LUNGS
Cellular Level..O2 from BLOOD to CELLS and CO2 from CELLS to BLOOD
Gas flow from
high pressure to low pressure
Units of Pressure
mmHg, cmH2O(vents) kPa (kiipascal)
Airway Pressure (Paw)
Alveolar pressure AKA
Pressure at BODY SURFACE
Pta..pressure gradient between mouth and alveoli..Produce air movement
Transairway Pressure Formula
Pressure gradient between alveoli and body surface...expands the lung and chest wall
Transthoracic Pressure Formula
Pressure gradient between alveoli and pleural space..maintains alveolar inflation.
Transpulmonary Pressure Formula
Ease with which the lungs distent...opposite of elastance...Think, big red balloon.
C or Cl
Cl=change in V/change in P Cl=ml(volume) / cmH20 (pressure)
Normal Cl in spontaneous breathing pt.
Normal Cl in Ventilator pt
Increase in Compliance....good or bad?
Good...Less pressure required to inflate lung.
decrease Compliance...good or bad?
Bad..More pressure required to inflate lung.
Frictional resistance to gas flow...(the size of the airway)
Things that decrease diameter of airway
bronchospasm..inflammation(edema)..increase in secretions,,ET tube
Increase in resistance...good or bad?
Bad...more pressure required to inflate lung (small straw)
decrease in resistance...good or bad?
Good...Less pressure rrequired to inflate lung (big straw)
Normal resistance for spont. breathing pt
normal resistance for vent breathing pt
How many seconds are needed to fill
How many part Inspiratory to expiratory (Total Cycle Time)
Negative Pressure Ventilators(Iron Lung)
INHALE mouth pressure > Alveolar pressure...Gas flows into lungs EXHALE Negative pressure removed, passive exhalation
Positive Pressure Ventilators
ET Tube, CPAP, Mouth Piece, Trach
High Freq. Ventilation
Ventilator that provides High Resp. Rate, Low Volumes..PISTON pushes gas in on I...draws gas out on E
High Frequency Jet Ventilator...Rates 100-600 bpm
High Frequency Ocillatory Ventilator...Rates up to 4000 bpm
Indications for High Freq. Vent
ARDS..and infants with surfactant issues
Where Inspiratory starts and Expiratory ends
Peak Pressure (PIP)
The highest pressure of the breath, I
Increase in PIP
Increase in Resistance, Decrease in compliance
Decrease in PIP
Decrease in resistance, Increase in compliance
Plateau Pressure (Pplateau)
Set for one sec. Breath hold at the end of Inspiration...measures pressure with NO gas flow .TRUE PICTURE OF LUNG COMPLIANCE(STIFFNESS)
Settings for Pplateau on VENT
Inspiratory Pause, Inspiratory Hold, Plateau
disease that leads to INCREASED compliance
4 factors that change the ability of air to flow through the conducting airways
1 gas viscosity, 2 gas density 3 diameter of the tube 4 flow rate of the gas
increased resistance of 13-18
indicates disease such as emphysema and asthma and other obstructive disorders
less pressure in alveoli, smaller volume of gas available for gas exchange. Accessory muscle use, for breathing.
A stiff lung..
fills and empties quickly, but gets less volume
A lung with increased resistance..
fills slowly, if normal amount of time is allowed, the lung will receive less volume
Recorded when there is no movement of air
Static Compliance Formula
Cs=Vt / Pplateau-Peep
Recorded with movement of air
Dynamic Compliance Formula
Cd=Vt / PIP-Peep
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