1) Cardiopulm Physiology Flashcards
Goals of CPPT?
- Prevent
- Mitigate
- Reverse CP dysfxn
What can any insult to the O2 transport system cause?
Impairments & decr exercise tol
What can abn’s of CV & pulm systems cause?
Limitations in physical fxning
Minute Ventilation
Movement of air in & out of the lungs as a result of respiratory muscle activity
Normal minute ventilation?
21%
Where does gas exchange occur?
Between alveoli & blood in pulmonary capillaries
Where must blood have sufficient transit time to allow for diffusion?
Pulmonary Capillary
On which side of the heart does oxygenated blood enter?
Left side
During what phase of the cardiac cycle does blood enter the heart?
Diastole
When blood enters the L ventricle, what is the myocardium up to?
Its relaxed & compliant
W/what conditions is myocardial compliance low?
MI & LVH
What does decr myocardial compliance cause?
- Impaired ability to fill L ventricle
- Decr CO
- Dyspnea
What will factors that alter the oxyhemoglobin dissociation curve affect?
O2 delivery to skeletal muscle
What happens w/a shift to the left of the oxyhemoglobin dissociation curve?
Impairs the amount of O2 extracted by muscle
What happens w/a shift to the right of the oxyhemoglobin dissociation curve & why?
Acidosis & incr body temp bc it facilitates O2 unloading from hemoglobin
Steps of O2 transport pathway
1) Fully O2-ed blood gets delivered to peripheral tissues
2) Cells uptake O2 from blood
3) Cells use O2
4) Partially desaturated blood is returned to the lungs
If a pt can’t generate (-) pressure, what might need to happen?
Night time ventilation
During inspiration, is alveolar or thoracic pressure greater & why?
Alveolar–>Bc of respiratory muscle contraction
Does the heart like positive pressures?
No
During exhalation, is alveolar or thoracic pressure smaller?
Alveolar
True or False: A healthy lung resists enlargement during inspiration.
True
Is a normal lung very compliant?
Yes
What happens to lungs of pt’s who have diseases that cause alveolar, interstitial, or pleural fibrosis & edema?
Lungs become rigid–>Decr compliance
What incr compliance?
Emphysema & age
What percent of RAW is the upper A/W responsible for?
45%
Laminar Flow
Streamlined flow of air molecules
Turbulent Flow
High AW resistance caused by frequent molecular collisions from mucus, exudate, tumor, & other obstructions
True or False: Healthy lungs should have a mix of laminar & turbulent flow
True
If a pt’s lungs have incr compliance, what does that mean for their chest & lungs?
Chest moves out & there’s decr recoil of lungs
In what region of the lungs is ventilation favored?
Lower lungs
Should O2 diffusion be a fast or slow process?
Fast
Perfusion
Blood in pulmonary circulation that’s available for gas exchange
What is perfusion dependent on?
- Pulmonary vascular resistance
- Ejection fraction
- Gravity
True or False: Pulmonary circulation operates at a low pressure compared to systemic circulation.
True
Normal PAP Range
10-20mmHg
What has a big effect on lung perfusion?
Hydrostatic Pressure
What does hydrostatic pressure have a big effect on?
Lung Perfusion
Hypoxia Vasoconstriction
Pulmonary blood vessels constriction in response to low arterial O2 pressure & low pH
*Protective reflex of moving blood away from underventilated/poorly oxygenated areas of the lung
What can hypoxia vasoconstriction cause?
Pulmonary HTN
What areas have the most optimal gas exchange?
Areas w/greatest amount of perfusion & ventilation
What can affect the VQ ratio?
Postural changes
Areas w/low VQ ratio (Q
A shunt
Areas w/high VQ ratios (V
Dead space
In what position is the VQ ratio best?
Upright
In what part of the lung does optimal VQ ratio occur?
Mid Lung
What problems can mess w/O2 transport?
- Respiratory muscle dysfxn
- Chest wall deformities
- VQ mismatching
- Diffusion abn’s
- Inadequate CO
- Peripheral blood flow limitations
- Low O2-carrying capacity
