OB Specialty Exam

Question 1

What is uterine blood flow a term pregnancy?

Answer 1

700-800 ml/min

Question 2

When is the fetus most susceptible to teratogenic effects?

Answer 2

3-8 weeks

Question 3

How should you treat respiratory depression in an infant born to a heroin addict?

Answer 3

Controlled ventilation

NOT naloxone - don’t want withdrawal

Question 4

What is the dose of naloxone for a non-addicted newborn?

Answer 4

0.1 mg/kg

Question 5

When do amniotic fluid embolisms occur?

Answer 5

During labor, delivery, c-section or postpartum

Question 6

Symptoms of amniotic fluid embolism

Answer 6

Tachypnea, respiratory distress, cyanosis, shock, generalized bleeding (DIC), CV collapse, seizure, pulmonary edema, coma, decreased BP

Question 7

What are 3 major pathophysiological manifestations of AFE?

Answer 7

Acute pulmonary embolism
DIC
Uterine atony

Question 8

What 4 clinical features are you likely to see in an AFE?

Answer 8

Dyspnea
Hypoxemia
CV collapse
Coma

Question 9

Why is morphine not routinely used for labor epidurals?

Answer 9

Long onset time (30-60 minutes)

Question 10

Why are high doses of epidural morphine not used?

Answer 10

Increased risk of delayed respiratory depression

Analgesia only effective for first stage of labor

Question 11

What is placenta previa?

Answer 11

The placenta covers the opening to the cervix

Question 12

When does onset of hemorrhage usually begin with placenta previa?

Answer 12

Near end of 2nd trimester or beginning of 3rd

Question 13

What is the incidence of placenta previa?

Answer 13

1 in 200 pregnancies

Question 14

What is the major symptom of placenta previa?

Answer 14

Painless vaginal bleeding

Question 15

How is placenta previa diagnosed?

Answer 15

Ultrasound

Question 16

What is the appropriate anesthetic plan for a primipara with placenta previa, active bleeding, and active labor?

Answer 16

C section + GETA

consider intubating with ketamine 0.5-1.0 mg/kg for hemodynamic stability

Question 17

What kind of regional anesthesia is inefficient at covering 2nd stage labor pain?

Answer 17

Pudendal block

Question 18

What events occur in 1st stage labor? 2nd? 3rd?

Answer 18

1st - dilation of cervix
2nd- delivery of baby
3rd-delivery of placenta

Question 19

What causes first stage labor pain?

Answer 19

Visceral pain from uterine contractions and cervical dilation

Question 20

Sensory dermatomes for labor pain (stages 1-3)?

Answer 20

1- T10-L1
2- T10-S4
3- T10-S4

Question 21

What causes second stage labor pain?

Answer 21

Stretching and compression of pelvic and perineal structures

Question 22

What sensory level is needed for a c-section?

Answer 22

T4

Question 23

What level is needed for a tubal ligation?

Answer 23

T4-5

Down to T10 can be adequate unless it doesn’t cover traction on viscera

Question 24

What is a normal fetal scalp PaCO2?

Answer 24

40-50 mmHg (same as mom)

Question 25

What is a normal fetal scalp pH?

Answer 25

7.25-7.35

Question 26

What is a normal fetal scalp SO2?

Answer 26

30-50%

Question 27

What is a normal fetal scalp PO2?

Answer 27

18-22 mmHg

Question 28

What is the most common direct cause of pregnancy related deaths?

Answer 28

Hypertensive disorders of pregnancy

Question 29

What are the most common morbidities encountered in obstetrics?

Answer 29

Severe hemorrhage and severe preeclampsia

Question 30

What are the categories scored for APGAR?

Answer 30

``` A- activity (muscle tone) P- pulse G- grimace A- appearance (skin color) R- respirations ```

Question 31

What APGAR scores are considered normal?

Answer 31

7-10

Question 32

What is average expected blood loss for a vaginal birth?

Answer 32

600 mL

Question 33

What is average expected blood loss for a c-section?

Answer 33

1000 mL

Question 34

What procedures generally require general anesthesia?

Answer 34

Bimanual massage of the uterus, manual extraction of retained placenta, reversion of inverted uterus, repair of a major laceration T6 level

Question 35

What three drugs are commonly used to treat uterine atony?

Answer 35

Pitocin 20-30 Units/L Methergine 0.2 mg IM Hemabate (carboprost) 0.25 mg IM

Question 36

Which muscle relaxants are safe to give to pregnant women?

Answer 36

Sux - undetectable in baby Most are fine (highly ionized) Atracurium and vecuronium are next best

Question 37

Do inhalational agents cross the placenta?

Answer 37

Yes - a lot. However, little fetal depression occurs when <1 MAC and delivery occurs within 10 minutes

Question 38

Do induction agents cross the placenta?

Answer 38

Yes! Thiopental, ketamine, propofol, benzos. | Usual induction doses not very detrimental/little fetal effects

Question 39

Do opiates cross the placenta?

Answer 39

Definitely! Can cause fetal respiratory depression. Morphine does this more than fentanyl. Don't give to mom until baby is out. Demerol - bad!! Toxic metabolite not cleared by baby - seizures

Question 40

Do local anesthetics cross the placenta?

Answer 40

Yes, to some degree. Some ion trapping if fetus is acidotic. Esp. with lidocaine. Highly protein bound LAs (bupivacaine, Ropivacaine) don't cross much.

Question 41

Which anticholinergics cross the placenta?

Answer 41

Atropine, scopolamine Glycopyrrolate - NO!

Question 42

Which first line vasopressor is recommended for pregnant women?

Answer 42

Phenylephrine

Question 43

How is pregnancy induced hypertension defined?

Answer 43

Systolic >140 or diastolic >90. Or Increase sbp by 30 or dbp by 15 above patient's baseline

Question 44

What is the classic triad of symptoms in pre-eclampsia?

Answer 44

Proteinuria, HTN, edema

Question 45

When does pre-eclampsia typically occur? When does it resolve?

Answer 45

Occurs after 20 weeks, resolves 48 hours after delivery

Question 46

What EKG changes are seen with excessive magnesium administration?

Answer 46

Widened QRS Also - PQ interval prolongation, SA and AV block, cardiac arrest

Question 47

What is used to treat magnesium toxicity?

Answer 47

Calcium

Question 48

What percentage of pregnancies are affected by preeclampsia?

Answer 48

7%

Question 49

What is the therapeutic range for MgSO4?

Answer 49

4-8 mEq/L

Question 50

Which of the following anti HTN drugs used to treat severe PIH is not capable of causing increased postpartum hemorrhage? Nitroprusside, nifedipine, NTG, labetalol, diazoxide

Answer 50

Labetalol

Question 51

What does HELLP stand for?

Answer 51

Hemolysis Elevated Liver enzymes Low Platelets

Question 52

What does VBAC stand for?

Answer 52

Vaginal birth after c-section

Question 53

What is a normal maternal PaCO2 in the third trimester?

Answer 53

27-32 mmHg

Question 54

What is the most common cause of breech presentation?

Answer 54

Prematurity

Question 55

What percent of maternal peripartum deaths are attributable to anesthesia?

Answer 55

2-3%

Question 56

What is a normal fetal heart rate?

Answer 56

120-160 bpm

Question 57

What is a normal fetal heart rate variability?

Answer 57

5-10 bpm

Question 58

What is the incidence of gestational diabetes?

Answer 58

2-3%

Question 59

What are two indications for magnesium in pregnant patients?

Answer 59

Anticonvulsant for preeclampsia Tocolytic agent (prevent preterm delivery)

Question 60

What is the therapeutic blood level for magnesium?

Answer 60

4-8mEq/L

Question 61

What are the side effects of magnesium?

Answer 61

Sedation, respiratory paralysis, increased sensitivity to nondepolarizng NMBD, antagonism of alpha adrenergic agonists, antagonism of NMDA receptors

Question 62

Are early decelerations in fetal HR a problem? What causes them?

Answer 62

No. Caused by head compression -> Vagal response (NOT hypoxia)

Question 63

Are late decelerations in fetal HR a problem? What causes them?

Answer 63

Yes! Caused by uteroplacental insufficiency -> hypoxia -> central chemoreceptors -> Vagal discharge

Question 64

What is a normal oxyhemoglobin p50 for a healthy person? A pregnant woman? A fetus?

Answer 64

- 27 mmHg normal - 30 mom - 19 baby

Question 65

What causes a rightward shift in the oxyhemoglobin dissociation curve?

Answer 65

Increase in - CO2 - H+ ions - 2,3 DPG - elevation - temperature

Question 66

What is an appropriate volume of hyperbaric bupivacaine (0.75%) for a spinal for c-section? How long will it last?

Answer 66

1.6-1.8 mL (12-13.5 mg) | Lasts 120-180 minutes

Question 67

What is an appropriate volume of local anesthetic solution for an epidural for c-section?

Answer 67

15-25 mL

Question 68

What are 3 commonly used LAs for use in epidurals for c-section?

Answer 68

3% chloroprocaine 2% lidocaine + epi 1:200,000 0.5% bupivacaine or Ropivacaine

Question 69

Name 4 side effects of intrathecal opioids

Answer 69

- pruritus - nausea/vomiting - sedation - respiratory depression

Question 70

FDA drug classification for use during pregnancy: Controlled studies show no risk.

Answer 70

Category A

Question 71

FDA drug classification for use during pregnancy: No evidence of risk in humans. Either animal findings show risk but human findings do not; or no adequate human studies have been done, animal findings are negative

Answer 71

Category B

Question 72

FDA drug classification for use during pregnancy: Risk cannot be ruled out. Human studies are lacking, potential benefits may justify potential risk

Answer 72

Category C

Question 73

FDA drug classification for use during pregnancy: Positive evidence of risk. Investigational or post-marketing data show risk to the fetus. Potential benefits may outweigh the potential risk.

Answer 73

Category D | warfarin, valproic acid, lithium

Question 74

FDA drug classification for use during pregnancy: Contraindicated in pregnancy. Studies in animals or humans have shown fetal risks which clearly outweigh any possible benefits to the patient

Answer 74

Category X | thalidomide

Question 75

How does Rh- incompatibility occur?

Answer 75

When the woman is Rh negative and the baby inherits Rh positive blood from the father

Question 76

When does maternal sensitization to Rh positive blood occur?

Answer 76

Very late in pregnancy or during childbirth. (mixing of baby's and mom's blood) Also: miscarriage, induced abortion, or ectopic pregnancy, or amniocentesis

Question 77

What is Rh iso-immunization?

Answer 77

Development of antibodies against Rh positive proteins following a blood transfusion

Question 78

Is Rh incompatibility bad for mom, baby, or both?

Answer 78

Baby.

Question 79

What are 3 major symptoms of Rh incompatibility in the newborn?

Answer 79

1) anemia 2) swelling of the body (associated with heart failure and respiratory problems) 3) kernicterus (neurologic syndrome)

Question 80

How is Rh incompatibility prevented?

Answer 80

Immune globulin injection (RhoGam) at week 28 of pregnancy

Question 81

How are newborns treated for Rh incompatibility?

Answer 81

If mild: aggressive hydration, phototherapy If swelling present: amniocentesis, intrauterine fetal transfusion, early induction of labor, treatment for congestive failure and fluid retention If kernicterus: exchange transfusion, phototherapy

Question 82

Under what weight is considered low birth weight?

Answer 82

Under 2500 grams (5.5 lbs)

Question 83

What is the extra risk with bupivacaine in regional anesthesia?

Answer 83

High potential for local anesthetic toxicity if injected IV. Difficult resuscitation due to high protein binding and lipid solubility

Question 84

Which opioid produces the worse fetal respiratory depression?

Answer 84

Morphine

Question 85

Before what week is birth defined as preterm?

Answer 85

37 weeks

Question 86

What kind of labor pain is covered by a pudedal block?

Answer 86

2nd stage labor pain

Question 87

Wha are 3 complications of a pudendal nerve block?

Answer 87

1) hit the fetus with a needle 2) IV injection 3) retro peritoneal hematoma

Question 88

What are the top 6 risk factors for maternal morbidity?

Answer 88

1) advanced maternal age (>34) 2) non-white ethnic group 3) multiple pregnancies 4) history of HTN 5) previous postpartum hemorrhage 6) emergency C-section