Ventilation
- Total ventilation / respiratory minute volume = Tidal volume (TV) ×
Respiratory rate (RR)
- Amount of air that reach the alveoli is called alveolar
ventilation
- Alveolar ventilation = ( Tidal volume – Dead space volume ) ×
Respiratory rate
- VA = ( TV – DSV ) ×
RR
Dead space
- Anatomical dead space – airways proximal to respiratory
bronchioles
- Physiological dead space – total volume of air not
equilibrating with
- In the healthy individual two dead spaces are almost
identical
Reginal difference
In upright position
- Lower regions are ventilated better than upper zones
In supine position
- Apical regions are better ventilate than basal regions
- Lowermost regions are better ventilate than basal regions
- Alveolar ventilation is more efficiently increased by doubling
the TV than doubling than respiratory rate
- Increasing PIO2 is better than increasing
alveolar ventilation in the treatment for hypoxia
Oxygen Cascade
Factors affecting PAO2( arterial partial pressure
of oxygen )
- PIO2
- RR
- TV
- DSV
- O2 consumption
Labels: Revision, RS, RS Revision