(VERSION A, TEST SCORE 94%) RESP 1220 - UNIT
2 Physiology of Ventilatory Support
Pressure at airway opening
What does Pawo mean?
(Zero @ end-exhalation)
Alveolar pressure
What does Palv mean? - Zero @ end-exhalation
- When diaphragm contracts, becomes negative
Intrapleural pressure
What does Ppl mean? - @ end-exhalation, slightly negative
- when diaphragm contracts, becomes more negative
Atmospheric or pressure at body surface
What does Pbs mean?
(Zero @ end-exhalation)
Under normal - Decreased Palv (alveolar pressure)
cicumstances, a - Increased Ptaw (transairway pressure) & Inspiration
decreased Ppl (intrapleura of Vt (Tidal Volume)
pressure) results in...
What is NPV? Negative-Pressure Mechanical Ventilation
What is PTP? transpulmonary pressure
What is PTA? Transthoracic airway pressure
What is PPV? Positive Pressure Mechanical Ventilation
, Minute ventilation
What is VE? - The amount of air entering (or exiting) the lung
each minute
What is VA? Alveolar Ventilation
*What is indicated by a Respiratory Acidemia by inadequate VA (alveolar
PaCO2 (greater than) >45 ventilation)
& pH (less than) <7.35? - to correct it, increase VE (Minute ventilation)
How would you correct it?
What is indicated by a Respiratory Alkalemia, VA (alveolar ventilation) is
PaCO2 (less than) <35 & too high
(greater than) >7.45? - to correct, decrease VE (minute ventilation)
Positive End-Expiratory Pressure
What is PEEP and CPAP? Continuous Positive Airway
Pressure
(Interchangeable, means the same)
Tissue Oxygen Delivery
What is DO2?
Normal: 990 ml/min
Peak Inspiratory Pressure (AKA Peak Pressure or Peak
Airway Pressure)
*What is PIP? - Pressure necessary to overcome airway resistance
& lung and chest wall compliance.
- less than (<) 40 cmH2O
Plateau pressure
- pressure observed during a period of inflation hold
*What is Pplat?
or end inspiratory pause
- less than (<) 30 cmH2O
Quasistatic lung-thorax compliance
What is Cstatic? VT/(Pplat-PEEP)
Normal: 0.2 L/cmH2O
Airway
resistance (PIP-
What is Raw? Pplat)/flow
Normal: 0.5-2.25 cmH2O/L/sec
*Pplat should be kept less than 30 cmH2o, if needed..
decrease pressure or VT
2 Physiology of Ventilatory Support
Pressure at airway opening
What does Pawo mean?
(Zero @ end-exhalation)
Alveolar pressure
What does Palv mean? - Zero @ end-exhalation
- When diaphragm contracts, becomes negative
Intrapleural pressure
What does Ppl mean? - @ end-exhalation, slightly negative
- when diaphragm contracts, becomes more negative
Atmospheric or pressure at body surface
What does Pbs mean?
(Zero @ end-exhalation)
Under normal - Decreased Palv (alveolar pressure)
cicumstances, a - Increased Ptaw (transairway pressure) & Inspiration
decreased Ppl (intrapleura of Vt (Tidal Volume)
pressure) results in...
What is NPV? Negative-Pressure Mechanical Ventilation
What is PTP? transpulmonary pressure
What is PTA? Transthoracic airway pressure
What is PPV? Positive Pressure Mechanical Ventilation
, Minute ventilation
What is VE? - The amount of air entering (or exiting) the lung
each minute
What is VA? Alveolar Ventilation
*What is indicated by a Respiratory Acidemia by inadequate VA (alveolar
PaCO2 (greater than) >45 ventilation)
& pH (less than) <7.35? - to correct it, increase VE (Minute ventilation)
How would you correct it?
What is indicated by a Respiratory Alkalemia, VA (alveolar ventilation) is
PaCO2 (less than) <35 & too high
(greater than) >7.45? - to correct, decrease VE (minute ventilation)
Positive End-Expiratory Pressure
What is PEEP and CPAP? Continuous Positive Airway
Pressure
(Interchangeable, means the same)
Tissue Oxygen Delivery
What is DO2?
Normal: 990 ml/min
Peak Inspiratory Pressure (AKA Peak Pressure or Peak
Airway Pressure)
*What is PIP? - Pressure necessary to overcome airway resistance
& lung and chest wall compliance.
- less than (<) 40 cmH2O
Plateau pressure
- pressure observed during a period of inflation hold
*What is Pplat?
or end inspiratory pause
- less than (<) 30 cmH2O
Quasistatic lung-thorax compliance
What is Cstatic? VT/(Pplat-PEEP)
Normal: 0.2 L/cmH2O
Airway
resistance (PIP-
What is Raw? Pplat)/flow
Normal: 0.5-2.25 cmH2O/L/sec
*Pplat should be kept less than 30 cmH2o, if needed..
decrease pressure or VT
