Non invasive positive pressure ventilation (NIPPV) using pressure support mode (bi-level nasal positive pressure) is effective in restoring
alveolar ventilation during sleep (110).
Indeed, this artificial carbon dioxide removal was so efficient that, when extracorporeal carbon dioxide removal approximated carbon dioxide production,
alveolar ventilation could almost be ceased (37).
While this pattern of breathing will reduce the work of breathing, dead space ventilation is increased and
alveolar ventilation reduced (24).
Of the studied physiologic factors, the blood:air partition coefficient and
alveolar ventilation were most significant in determining the respiratory uptake (p < 0.
2]-free gas expired from the large airway and tracheal tube dead space, Phase H represents a mixture of gas from both the large airway dead space and alveolar dead space and Phase III (or alveolar plateau) represents
alveolar ventilation (13,14).
Ventilator dyssynchrony can cause increased intrathoracic pressure, decreased
alveolar ventilation, and increased work of breathing for the patient.
Assuming the anatomical deadspace in intubated patients to be approximately 70 ml (12), the reduction of
alveolar ventilation during PC ventilation would be close to 40% which could be expected to increase the [P.
They likewise stimulate increase
alveolar ventilation and acute respiratory alkalosis.
8 in the equation immediately following; getting 'A' and 'a' confused as subscripts when referring to alveolar and arterial partial pressures; the partial pressure of carbon dioxide is certainly proportional to the ratio of production to
alveolar ventilation, but it is certainly not equal to this ratio.
Hypoxia through a chemoreceptor mechanism increases the depth of
alveolar ventilation, which can be increased by as much as 60 percent at higher elevations.
If stimuli increase or decrease the volume of air inspired and/or the rate of breathing, this decides the amount of
alveolar ventilation, which determines the PaCO2 measured in arterial blood.
