OB ANESTHESIA PRACTICE QUESTIONS
2025 WITH CORRECT ANSWERS
CV changes that accompany a normal pregnancy include an increased: (Select 3)
a. SVR
b. HR
c. plasma volume
d. SV
e. SBP
f. DBP - ....ANSWER ...-Answer: b, c, d
Rationale:
-SVR decreases
-CO increases
-DBP decreases
-SBP unchanged
-SV increases
-HR increases
-Plasma volume increases
....FOR STUDY PURPOSES...©️2025 ALL RIGHTS RESERVED... 1
,-Erythrocyte volume increases
A pregnant mother has a history of mitral stenosis. When is she at GREATEST risk of
hemodynamic compromise?
a. second trimester
b. third trimester
c. second stage of labor
d. third stage of labor - ....ANSWER ...-Answer: third stage of labor
Rationale: CO is 80-100% over prelabor value during third stage of labor (after delivery).
Patients w/ a history of valvular stenosis or pulmonary HTN are at greatest risk of
compromise when CO is highest.
P50:
a. increases in the mother and decreases in the fetus
b. decreases in the mother and increases in the fetus
c. remains constant in the mother and decreases in the fetus
d. remains constant in the mother and increases in the fetus - ....ANSWER ...-
Answer: increases in the mother and decreases in the fetus
Rationale: The OxyHgb curve tells us the tendency of hgb to bind to oxygen and P50 is
the PaO2 where hgb is 50% saturated by O2. A high P50 reflects a right shift (right =
release). A lower P50 reflects a left shift (left = love)
....FOR STUDY PURPOSES...©️2025 ALL RIGHTS RESERVED... 2
, To ensure fetal oxygenation, there has to be an O2 concentration gradient from mother
to fetus. Mother P50 is higher = 30 mmHg, Fetal P50 is lower = 19 mmHg. The higher
P50 in mother & lower P50 in fetus ensures O2 offloading across placenta.
Which arterial blood gas is MOST likely to occur in a pregnant patient's first trimester?
a. 7.42/30/101/20
b. 7.36/36/97/22
c. 7.33/44/96/19
d. 7.45/31/85/19 - ....ANSWER ...-Answer: a.
Rationale: Progesterone is a respiratory stimulant, increasing MV up to 50%. PaCO2
decreases ~30 (respiratory alkalosis), renal compensation - HCO3 decreases ~20
(metabolic acidosis), pH unchanged.
All of the following increase the risk of pulmonary aspiration before the onset of labor
EXCEPT:
a. increased gastrin secretion
b. decreased gastric emptying
c. decreased gastroesophageal barrier pressure
d. increased progesterone production - ....ANSWER ...-Answer: decreased gastric
emptying
....FOR STUDY PURPOSES...©️2025 ALL RIGHTS RESERVED... 3
2025 WITH CORRECT ANSWERS
CV changes that accompany a normal pregnancy include an increased: (Select 3)
a. SVR
b. HR
c. plasma volume
d. SV
e. SBP
f. DBP - ....ANSWER ...-Answer: b, c, d
Rationale:
-SVR decreases
-CO increases
-DBP decreases
-SBP unchanged
-SV increases
-HR increases
-Plasma volume increases
....FOR STUDY PURPOSES...©️2025 ALL RIGHTS RESERVED... 1
,-Erythrocyte volume increases
A pregnant mother has a history of mitral stenosis. When is she at GREATEST risk of
hemodynamic compromise?
a. second trimester
b. third trimester
c. second stage of labor
d. third stage of labor - ....ANSWER ...-Answer: third stage of labor
Rationale: CO is 80-100% over prelabor value during third stage of labor (after delivery).
Patients w/ a history of valvular stenosis or pulmonary HTN are at greatest risk of
compromise when CO is highest.
P50:
a. increases in the mother and decreases in the fetus
b. decreases in the mother and increases in the fetus
c. remains constant in the mother and decreases in the fetus
d. remains constant in the mother and increases in the fetus - ....ANSWER ...-
Answer: increases in the mother and decreases in the fetus
Rationale: The OxyHgb curve tells us the tendency of hgb to bind to oxygen and P50 is
the PaO2 where hgb is 50% saturated by O2. A high P50 reflects a right shift (right =
release). A lower P50 reflects a left shift (left = love)
....FOR STUDY PURPOSES...©️2025 ALL RIGHTS RESERVED... 2
, To ensure fetal oxygenation, there has to be an O2 concentration gradient from mother
to fetus. Mother P50 is higher = 30 mmHg, Fetal P50 is lower = 19 mmHg. The higher
P50 in mother & lower P50 in fetus ensures O2 offloading across placenta.
Which arterial blood gas is MOST likely to occur in a pregnant patient's first trimester?
a. 7.42/30/101/20
b. 7.36/36/97/22
c. 7.33/44/96/19
d. 7.45/31/85/19 - ....ANSWER ...-Answer: a.
Rationale: Progesterone is a respiratory stimulant, increasing MV up to 50%. PaCO2
decreases ~30 (respiratory alkalosis), renal compensation - HCO3 decreases ~20
(metabolic acidosis), pH unchanged.
All of the following increase the risk of pulmonary aspiration before the onset of labor
EXCEPT:
a. increased gastrin secretion
b. decreased gastric emptying
c. decreased gastroesophageal barrier pressure
d. increased progesterone production - ....ANSWER ...-Answer: decreased gastric
emptying
....FOR STUDY PURPOSES...©️2025 ALL RIGHTS RESERVED... 3
