Changes in Pregnancy

Question 1

What are the major changes in pregnancy?

Answer 1

1. Elevated diaphragm
2. Increased AP and transverse chest diameter
3. Increased respiratory drive (dec PaCO2)

Question 2

Discuss the Fetal blood supply

Answer 2

PO2 26-32 mmHg, saturation 80-90%, PCO2 28-42, pH 7.3-7.35

Question 3

Discuss the Maternal Arterial Blood Gases

Answer 3

pH 7.4-7.45, HCO3 18-21 mEq/L, PCO2 31mmHg

PO2: 106-108 mmHg (1st trimester)
PO2: 101-104 mmHg 3rd trimester

Question 4

What in particular changes in the mother’s respiratory drive?

Answer 4

1. Inc minute ventilation/VT/RR
2. Dec FRC/airway resistance
3. No Δ in VC/TLC
4. FRC decreases 10-20% in supine position
5. Possible atelectasis

Question 5

Management and Tx of Asthma in Pregnancy

Answer 5

1. Most common respiratory condition to complicate pregnancy

Budesonide, Beta 2 agonists
AVOID decongestants, and teratogenic drugs

Question 6

Pulmonary Embolism in Pregnancy

Answer 6

Virchow’s triad: Hemodynamic change (stasis, turbulence) + Endothelial Injury + Hypercoagulability

1. obstruction of blood flow a pulmonary a., usually precipitated by DV
2. Tx with unfractioned heparin or subcutaneous LMWH