NURS 6901 RESPIRATORY EXAM
2024-2025
What is peak inspiratory pressure (PIP)? - ANSWER This is the pressure required
to overcome both the airway and alveolar resistance (aka both the lungs and the
airway)
PIP = (Resistance x flow) + (elastance of respiratory system + TV) + PEEP
-As flow increases, turbulence increases, therefore increasing PIP
What are the causes of high PIP? - ANSWER 1. Bronchospasm
2. Retained secretions
3. Mucus plus
4. ETT tip occlusion
What is plateau pressure? - ANSWER This is the end-inspiratory distending
pressure of the lungs and occurs when the lungs are fully inflated (so it measures
the pressure of just the lungs)
-Helpful in measuring static compliance, airway resistance, and the initial pressure
support setting (if you know how much pressure the lungs can take in, that is your
max pressure)
What is static compliance? - ANSWER The compliance in the lungs when they are
fully extended
What are causes of high plateau pressure? - ANSWER This means there is a
problem with compliance of the lungs
1. Pneumothorax
2. Pulmonary edema
,3. ARDS
4. Pneumonia
What is the driving pressure? - ANSWER Driving pressure = plateau pressure -
PEEP
This is the pressure above the PEEP applied to the entire respiratory system to
achieve tidal ventilation
-Measures true compliance of the lungs, or what it takes to max inflate them
without PEEP
What is compliance? - ANSWER Compliance is always being addressed when you
see a change in volume/change in pressure
-It demonstrates the elastic forces of the lung
When is compliance the lowest? - ANSWER During inspiration; the elastic force
are overcome by transpulmonary pressure
When is compliance the highest? - ANSWER During expiration
What is hysteresis? - ANSWER The difference between transpulmonary pressure
of inhalation (increasing volume) and the pressure of exhalation (decreasing
volume)
Dynamic changes in airflow resistance can also contribute to hysteresis and overall
work of breathing
What is the Law of Laplace? - ANSWER This is a law that describes the
relationship between tension, pressure, and radius
For a spherical shape (like an alveoli):
P = 2T/R
Radius makes a huge difference
What is dead space? - ANSWER passageways that transport air but are not
available for gaseous exchange
How do you calculate minute ventilation? - ANSWER Min. ventilation - tidal
, volume x RR
Mve = TV x RR
How do you calculate alveolar ventilation? - ANSWER Alveolar Ventilation =
(Tidal Volume - Dead Space) x (Respiratory Rate)
= (TV - Vd) x RR
What is Bohr's equation? - ANSWER -This is an equation we use to calculate dead
space
Vd/Vt = (PaCO2 - PeCO2) / PaCO2
So figure out dead space....
Vd = TV (PaCO2 - PeCO2) / PaCO2
EtCO2 can be used instead of PeCO2
The greater the difference between arterial CO2 and exhaled CO2, the greater
amount of dead space
What is anatomic dead space? - ANSWER This is air that is confined to the
conducting airways
What is alveolar dead space? - ANSWER Alveoli that are ventilated but not
perfused
What is physiologic dead space? - ANSWER This = anatomic dead space +
physiologic (alveolar dead space)
2024-2025
What is peak inspiratory pressure (PIP)? - ANSWER This is the pressure required
to overcome both the airway and alveolar resistance (aka both the lungs and the
airway)
PIP = (Resistance x flow) + (elastance of respiratory system + TV) + PEEP
-As flow increases, turbulence increases, therefore increasing PIP
What are the causes of high PIP? - ANSWER 1. Bronchospasm
2. Retained secretions
3. Mucus plus
4. ETT tip occlusion
What is plateau pressure? - ANSWER This is the end-inspiratory distending
pressure of the lungs and occurs when the lungs are fully inflated (so it measures
the pressure of just the lungs)
-Helpful in measuring static compliance, airway resistance, and the initial pressure
support setting (if you know how much pressure the lungs can take in, that is your
max pressure)
What is static compliance? - ANSWER The compliance in the lungs when they are
fully extended
What are causes of high plateau pressure? - ANSWER This means there is a
problem with compliance of the lungs
1. Pneumothorax
2. Pulmonary edema
,3. ARDS
4. Pneumonia
What is the driving pressure? - ANSWER Driving pressure = plateau pressure -
PEEP
This is the pressure above the PEEP applied to the entire respiratory system to
achieve tidal ventilation
-Measures true compliance of the lungs, or what it takes to max inflate them
without PEEP
What is compliance? - ANSWER Compliance is always being addressed when you
see a change in volume/change in pressure
-It demonstrates the elastic forces of the lung
When is compliance the lowest? - ANSWER During inspiration; the elastic force
are overcome by transpulmonary pressure
When is compliance the highest? - ANSWER During expiration
What is hysteresis? - ANSWER The difference between transpulmonary pressure
of inhalation (increasing volume) and the pressure of exhalation (decreasing
volume)
Dynamic changes in airflow resistance can also contribute to hysteresis and overall
work of breathing
What is the Law of Laplace? - ANSWER This is a law that describes the
relationship between tension, pressure, and radius
For a spherical shape (like an alveoli):
P = 2T/R
Radius makes a huge difference
What is dead space? - ANSWER passageways that transport air but are not
available for gaseous exchange
How do you calculate minute ventilation? - ANSWER Min. ventilation - tidal
, volume x RR
Mve = TV x RR
How do you calculate alveolar ventilation? - ANSWER Alveolar Ventilation =
(Tidal Volume - Dead Space) x (Respiratory Rate)
= (TV - Vd) x RR
What is Bohr's equation? - ANSWER -This is an equation we use to calculate dead
space
Vd/Vt = (PaCO2 - PeCO2) / PaCO2
So figure out dead space....
Vd = TV (PaCO2 - PeCO2) / PaCO2
EtCO2 can be used instead of PeCO2
The greater the difference between arterial CO2 and exhaled CO2, the greater
amount of dead space
What is anatomic dead space? - ANSWER This is air that is confined to the
conducting airways
What is alveolar dead space? - ANSWER Alveoli that are ventilated but not
perfused
What is physiologic dead space? - ANSWER This = anatomic dead space +
physiologic (alveolar dead space)
