Respiratory physiologic changes during pregnancy Flashcards
Parturients are likely to have upper airway swelling affecting nasal passages oropharynx, epiglottis, larynx and trachea. This is due to?
- Increased progesterone, estrogen and relaxin causing vascular engorgement and hyperemia.
- Increased intracellular volume.
Airway edema in parturients is made worse by?
- Preeclampsia
- tocolytics
- prolonged trendelenburg position
How is mallampati score affected during pregnancy?
It increases during pregnancy
Difficult intubation is _________ times higher in full term patients
8
A downsized ett 6-7 is recommended in parturients because?
The glottic opening is narrowed
_______ relaxes the ligaments in the rib cage during early pregnancy leading to an increased anterior posterior diameter of the rib?
Relaxin
AS the gravid uterus grows, it shifts the diaphragm in a cephalad direction. These changes affect the lungs in what ways?
- FRC (RV+ERV) is reduced
- Increased O2 consumption + decreased FRC = hypoxemia during apnea => brain death of mother and fetus.
- FRC falls below closing capacity at tidal breathing.
Minute ventilation is increased by ________ due to________
Increased O2 consumption and CO2 production
Respiratory stimulant effect of progesterone
____________ explains the increased PO2 in the parturient.
A small reduction in physiologic shunt
The increased PO2 increases __________
driving pressure of oxygen across the placenta
What is the normal PaCO2 during pregnancy?
28-32
Renal compensation maintains pH by eliminating bicarb
What is the normal bicarb during pregnancy
20
Compensated decreased pH caused by increased minute ventilation
How is tidal volume and respiratory rate affected during pregnancy?
Vt increases by 40%
RR increases by 10%
How is total lung capacity affected
It decreases by 5%
Increased rib cage diameter compensated for increased diaphragm position.
How is vital capacity affected
No change
