Obstetrics

Question 1

When is maternal cardiac output the highest?

Answer 1

Immediately following delivery: this is because venous compression is relieved, there is some auto transfusion from uterine contraction, and there is no longer fetal dependence on mother’s circulation

It will fall rapidly and be back to normal around 2 weeks

Question 2

What are the two hemodynamic parameters that either do not change, or decrease in pregnancy?

Answer 2

CVP remains the SAME, and venous capacitance increases, meaning that SVR DECREASES. Everything else, including HR, SV, volume, plasma volume, RBC mass increase

Question 3

What are the respiratory changes seen during ACTIVE LABOR?

Answer 3

1. Increased MV due to Increased TV and RR
2. Decreased PaCO2, leading to a L shift in the O2 dissociation curve
3. Increased O2 consumption
4. Decreased alveolar dead space due to an increase in CO

Question 4

What are the two HR cutoffs for fetal bradycardia and their interventions?

Answer 4

1. < 100 bpm: provide PPV

2. < 60 bpm: perform chest compressions at a rate of 3:1 (3 compressions, 1 breath)

Question 5

What happens to coagulation factors in pregnancy? Which 2 are affected the most?

Answer 5

1. Increase in factors
2. Factor VII and fibrinogen are increased the most
3. Resistance to protein C and levels of protein S decrease
4. Factors XIII and XI, AT III and tPa decrease

Question 6

What is the first line treatment for uterine atony? What treatment should you avoid in a patient with pre-eclempsia?

Answer 6

1. Oxytocin given as a slow infusion. Do not give as a bolus or a rapid infusion, as this will cause uterine relaxation
2. Avoid methylergotamine in patients with pre-eclempsia, as this causes massive vasoconstriction and can worsen HTN

Question 7

What are the signs of amniotic fluid embolism?

Answer 7

Cardiogenic shock, consumptive coagulopathy, pulmonary HTN, and fetal bradycardia

Question 8

What intervention should you use for cerclage placement with bulging cervix vs. prophylactic cerclage?

Answer 8

1. Cerclage with bulging cervix requires uterine relaxation –> perform a GA, this will relax the uterus
2. Prophylactic cerclage would be best performed under neuraxial technique (aka Spinal)

Question 9

What places a person at a higher risk for PDPH?

Answer 9

Female gender

Question 10

What mediates FHR variability?

Answer 10

PS tone

Question 11

What causes early, late, and variable decelerations?

Answer 11

1. Early: benign finding, due to compression of the head
2. Late: due to hypoxia, seen with placental insufficiency
3. Variable: due to umbilical cord compression –> the relationship to the contraction is variable

Question 12

What factor is increased in pre-eclempsia?

Answer 12

1. Thromboxane A2

Question 13

What determines the low placental transfer of Bupivicaine?

Answer 13

High protein binding

Question 14

What values indicate an AKI in a pregnant woman?

Answer 14

Serum Cr > 0.8 mg/dl

BUN > 13

Question 15

What are the respective blocks available for stage 1 or stage 2 labor?

Answer 15

1. Stage 1: Paracervical block – though this can lead to fetal bradycardia
2. Stage 2: Pudendal block

Question 16

What are the two placental abnormalities associated with Breech presentation?

Answer 16

1. Cornual placenta

2. placenta previa

Question 17

Describe the risks and benefits of performing a CS vs. a vaginal birth.

Answer 17

1. CS: Decreased risk of INITIAL uterine rupture and maternal hemorrhage
2. However, CS has more risks and a longer hospital stay than vaginal births

Question 18

What is the MOA of Terbutaline?

Answer 18

B2 agonist that binds to the uterine muscle to activate adenylyl cyclase, which leads to decreased Ca
- can cause tachycardia and pulmonary edema

Question 19

What medication is used to facilitate fetal version, vaginal delivery of breech kiddo, or removal of retained placental contents?

Answer 19

Nitroglycerine

Question 20

What two therapies are recommended for pre term labor?

Answer 20

1. Corticosteroids: reduces morbidity and mortality

2. Magnesium: neuroprotective in kids in pre term labor

Question 21

What are some causes of Polyhydramnios?

Answer 21

Duodenal atresia, TE fistula, inhibition of fetal swallowing

Question 22

What effect does lisinopril have on amniotic fluid production?

Answer 22

It causes oligohydramnios

Question 23

What metabolic derangement is seen with high dose Oxytocin use? Why?

Answer 23

Hyponatremia. This is because high doses of oxytocin lead to decreased renal excretion of fluid. This fluid overload then stimulates natriuresis.

Question 24

What is the major disadvantage to doing a paracervical block during labor?

Answer 24

It causes fetal bradycardia, possibly due to vasoconstriction of local anesthetic injection

Question 25

What is the electrolyte abnormality seen with Terbutaline?

Answer 25

Hypokalemia

Question 26

What gas is LEAST likely to cause uterine relaxation in a GA for a pregnant woman?

Answer 26

N20

Question 27

What effect does Nitrous Oxide have on pulmonary pressures?

Answer 27

It increases PVR

Question 28

What is the structure of Glycopyrrolate? Does it cross the placental barrier?

Answer 28

1. Quaternary amine 2. It does NOT cross the placenta * In general, things that cross the BBB will cross the placental barrier

Question 29

What are the characteristics of drugs that cross the placental barrier?

Answer 29

1. Small 2. Uncharged 3. Unionized 4. Low protein binding 5. High concentration of free drug

Question 30

What will PTT and PT show in Antiphospholipid antibody syndrome?

Answer 30

1. PTT: prolonged | 2. PT: normal

Question 31

What is the most common cause of postpartum hemorrhage?

Answer 31

Uterine atony

Question 32

What are the criteria that indicate severe pre-eclampsia?

Answer 32

1. BP > 160/110 2. Thrombocytopenia 3. Liver impairment 4. Renal impairment 5. CNS or visual disturbances 6. Pulmonary edema

Question 33

What are the criteria to diagnose Pre-eclampsia?

Answer 33

BP > 140/90 on two separate occasions in a pregnant woman > 20 weeks who did NOT have HTN before

Question 34

What two agents are used for uterine relaxation in Inversion? How about for retained placenta?

Answer 34

1. For inversion: use magnesium and terbutaline | 2. For retained placenta: use NG

Question 35

What effect does neuraxial anesthesia have on temperature?

Answer 35

It causes vasodilation below the level of the block. This leads to a redistribution of blood that lowers the core temperature. Additionally, the levels below the block cannot sense the cold, and the threshold for shivering is lowered. When patients start to shiver, they shiver above the level of the block, which cannot generate enough heat to cover the levels below the block. Non-thermogenic shivering is also a possibility. AKA is not related to the actual core temperature

Question 36

What effect does Terbutaline have on fetal insulin levels?

Answer 36

Causes hyperinsulinemia: This is because the mother is hyperglycemic and the glucose transfers to the fetus, but the insulin does not. The fetus then compensates by increasing production of insulin

Question 37

What is the most common cause of maternal mortality in labor?

Answer 37

Cardiovascular diseases

Question 38

What levels are targeted when doing neuraxial analgesia for a C-section?

Answer 38

T4-S4

Question 39

What is the treatment for pruritic associated with neuraxial opioids?

Answer 39

Nalbuphine

Question 40

What is the MOA of Ritrodine?

Answer 40

B2 agonist used for uterine relaxation. It increases uterine blood flow

Question 41

When might prostaglandins be CI in patients with uterine atony?

Answer 41

If they have asthma. Carboprost can lead to increased PVR, that can lead to pulm HTN and bronchoconstriction. In general, prostaglandins cause bronchoconstriction

Question 42

What pH and lactate levels define fetal acidemia?

Answer 42

1. pH < 7.20 | 2. Lactate > 4.8

Question 43

What value on an ABG is increased in a pregnant woman vs. a healthy woman?

Answer 43

PaO2: this is due to increased MV

Question 44

According to the ASA, what is the difficult airway algorithm?

Answer 44

If the baby is not in distress, wake up the patient. If the baby is distressed and you CAN mask ventilate, either continue masking, or throw in an LMA. If you CANNOT mask, put in an LMA or perform a surgical airway.

Question 45

When is vWD a CI to neuraxial anesthesia?

Answer 45

If disease is severe (and sometimes moderate can be CI). It is all based upon Factor VIII levels, so a patient should undergo lab testing prior to neuraxial anesthesia if it is not an emergency

Question 46

What are the cut offs for APGAR scores?

Answer 46

< 3 means necessary resuscitation 4-7 moderate, requires observation 8-10 is normal

Question 47

When is it safest to perform non-obstetric surgery in a pregnant woman?

Answer 47

In the second trimester. No anesthetic technique has been shown to reduce the risk of pre-term labor or miscarriage