Respiratory Physiology Flashcards
What is the most common etiology of hypoxemia in the PACU?
V/Q Mismatch
Intrapleural pressure becomes positive during:
forced exhalation
Transpulmonary pressure
is the pressure inside of the airway (it keeps the airway open) aka intrathoracic pressure, intrapulmonary pressure
What is the transpulmonary pressure equation?
TPP = alveolar pressure - intrapleural pressure
During tidal breathing, ___ is always positive and ___ is always negative.
transpulmonary pressure (+), intrapleural pressure (-)
Which muscles provide the most significant contribution to forced exhalation?
Abdominal muscles (rectus abdominis, transverse abdominis, internal obliques, external obliques)
The best ventilated alveoli:
are the most compliant: they exchange more gas because their volumes change more throughout the respiratory cycle
What is dead space?
Ventilation without perfusion
What is shunt?
Perfusion without ventilation
What is the most common cause of deadspace under general anesthesia?
A reduction in cardiac output
How do COPD and PE contribute to deadspace?
They increase deadspace
They increase deadspace
What are some causes of deadspace?
anticholinergics, mechanical ventilation, neck extension, adding a heat and moisture exchanger between the y-piece and the OETT, and an incompetent unidirectional valve
Where does deadspace begin on the breathing circuit?
the y-piece; increasing the length of the inspiratory or expiratory limb of the anesthesia circuit does NOT affect deadspace
Assuming MV is held constant, what does is the consequence of adding a heat and moisture exchanger between the OETT and the y-piece?
PaCO2 increase, PaO2 decrease
