Ventilation Flashcards
Which of the following pressure gradients is responsible for maintaining alveolar inflation?
Transpulmonary pressure gradient
What happens during normal inspiration?
Transpulmonary pressure gradient widens
Palv drops below that at the airway opening
The pp increases further
What is vital capacity
Maximum volume of air that can be exhaled following a maximum inspiration or inhaled following a maximum expiration (4800) (IRV + VT + ERV)
Laminar flow found in nose, mouth, trachea
False
Which pressure normally remains negative during quiet breathing
Ppl (pleural pressure)
The presence of pulmonary surfactant in the alveoli tends to do which of the following
Increase compliance
Elastic forces which must be overcome to move air into the respiratory system includes
Elasticity of the lung
Surface tension in the alveoli
What is the calculated measurement of a lung compliance?
0.2L
Mechanical WOB
Change in pressure x change in volume
In healthy lungs total WOB can be attributed to frictional forces
1/3
Which is a single indicator of the adequacy of alveolar ventilation
PaCO2
Characteristic that could result from a lung that loses elastic fibers
Increased compliance
What is normal Raw?
0.5-2.5
What is hysteresis?
An air filled lung shows a difference between inspiratory lung volume and expiratory lung volume at any given pressure
In normal individuals approximately what fraction of the VT is water during ventilation
1/3
The presence of surface tension forces in the air filled lung decreases the elastic recoil of the lung
False
What is the normal range of minute ventilation (Ve) in a healthy adult
5-10 L/min
All the following statements are true concerning Poiseuilles Law
In order to maintain specific flow as the radius of a tube increases, the driving pressure must increase
Total lung-thorax compliance in normal individuals is about what level
0.1 L/cm H2O
Which pulmonary conditions can cause an increase in airway resistance
Bronchospasm
Partial obstruction
Mucosal edema
Not fibrosis (red volume)
In individuals with disorders characterized by an increased frictional WOB such as emphysema which breathing pattern results in the minimum work?
Slow and deep breathing
For healthy individuals at rest which of the following statements about exhalation is true
Exhalation will be passive, due to inspiratory stored potential energy
On inspecting a volume pressure curve of a restrictive lung disease below, which of the following characteristics Parrish to this condition
Decreased lung compliance
Approximately what % of the total resistance to gas flow occurs in the small airway less than 2mm
20%
At the EPP pressure inside the airway exceeds the PPI
False
A patient has a tidal volume of 525 ml with RR at 14 his Vd/Vt is 0.4. What’s the patient’s approximate alveolar ventilation
4.4L/min
Which of the following formulas are used to compute the time constant of a lung unit
Resistance x compliance
How does gravity affect the pleural pressure in an upright lung
The Ppl in the apex is more negative
If a patient has a 6mm et tube and was replaced with a 8mm
Less pressure to ventilate
Respiration is the process of moving air in and out of the lungs
False
In the person lying flat on their back which conditions would be true
The posterior portion of the lungs would o receive the most ventilation
What’s condition is an example that presents alveolar dead space
Pulmonary embolus
On inspecting a volume pressure curve what type of condition is shown
Obstructive
