Obstetrics II

Question 1

How does pregnancy effect WBC count?

Answer 1

Causes benign leukocytosis, so WBC count isn’t a reliable indicator of infection

Question 2

Are parturients at higher or lower risk for intraoperative awareness?

Answer 2

Oddly enough, higher. Because RSI for OB patients doesn’t include versed or opiods, for the baby’s sake

Question 3

How are plasma cholinesterases impacted by pregnancy?

Answer 3

They decrease by 25%, but increased blood volume offsets this decrease and prolonged NMB is uncommon

Question 4

How does pregnancy impact protein binding levels?

Answer 4

Decreases it, due to lower albumin and alpha glycoprotein concentrations. Results in a larger fraction of unbound, free drug -> increased risk of drug toxicity

Question 5

Do pregnant women need a higher or lower loading dose of a medication?

Answer 5

Usually has to be higher, because clearance is dramatically increased and the volume of distribution is larger

Question 6

Most structural abnormalities from teratogens occur when exposure falls between which days?

Answer 6

31-71, during organogenesis

Question 7

Which infections are teratogenic?

Answer 7

CMV, Herpes, Parvo, Rubella, Syphilis, Toxoplasmosis, VEEV

Question 8

What is the etiology of most developmental defects?

Answer 8

Genetic transmission and chromosomal abnormality

Question 9

Airway edema in parturients is made worse by:

Answer 9

Pre-E
Tocolytics
Prolonged Tburg

Question 10

Why is FRC reduced in pregnancy?

Answer 10

As the rib cage widens and tidal volume increases, the volume at end expiration is much lower

Question 11

How does a decrease in FRC impact airway closure?

Answer 11

In pregnant women, the FRC is BELOW the closing capacity, which means the airways close off during tidal breathing

Question 12

How does progesterone impact tidal volume?

Answer 12

It’s a respiratory stimulant
It increases minute ventilation by 50%

Question 13

What increases more: tidal volume or respiratory rate?

Answer 13

Vt increases by about 40%
RR increases by about 10%

Question 14

What hormones contribute to vascular engorgement and hyperemia in pregnancy?

Answer 14

Estrogen
Progesterone
Relaxin

Question 15

What type of laryngoscope handle is useful in pregnant women?

Answer 15

Datta handle (short)

Question 16

How does progesterone impact vasculature?

Answer 16

It causes nitric oxide release, leading to vasodilation

Question 17

Does PT/PTT increase or decrease during pregnancy?

Answer 17

Decrease (takes less time to form a clot)

Question 18

What is the most common cause of thrombocytopenia in pregnancy?

Answer 18

Gestational thrombocytopenia

Question 19

How is BP effected during pregnancy?

Answer 19

MAP and SBP stay the same. DBP decreases.

Question 20

What % of CO goes to the uterus?

Answer 20

10%

Question 21

What is uterine blood flow in ml/min?

Answer 21

700ml/min

Question 22

Is uterine blood flow autoregulated?

Answer 22

No. Almost entirely dependent on MAP and CO.

Question 23

Is uterine blood flow reduced by phenylephrine?

Answer 23

No

Question 24

How efficiently a drug will traverse any given membrane is determined by which principle?

Answer 24

Fick’s Principle

Question 25

What are drug characteristics that favor maternal transfer?

Answer 25

Molecular Weight < 500 High Lipid Solubility Non-ionized Non-polar

Question 26

Which drugs have no placental transfer?

Answer 26

NMBAs Heparin Glycopyrrolate Insulin

Question 27

Does phenylephrine cause more or less fetal acidosis than ephedrine?

Answer 27

Less

Question 28

What afferent pathway innervates the uterus and cervix?

Answer 28

Visceral C fibers from the hypogastric plexus

Question 29

Which LA reduced the efficacy of spinal morphine?

Answer 29

2-Chloroprocaine It antagonizes mu and kappa receptors in the spinal cord

Question 30

How are bupivacaine, ropivacaine, and levobupivacaine related?

Answer 30

Ropivacaine is the R-enantiomer of bupivacaine, which is a racemic mixture of both the R and S enantiomer Levobupivacaine is just the S enantiomer

Question 31

Compare ropivacaine to bupivacaine in terms of spinal anesthesia

Answer 31

Decreased risk of CV tox Decreased potency Decreased motor block

Question 32

Why isn't lidocaine frequently used in labor epidurals?

Answer 32

It causes high degree of muscle blockade (which makes it ideal for C/S) Also, it crosses the placenta to a greater degree than the alternatives

Question 33

Can you use lidocaine for a Spinal?

Answer 33

No. Its associated with neurotoxicity in the intrathecal space

Question 34

Which opioid possesses LA properties?

Answer 34

Meperidine

Question 35

There are three ways you can get a total spinal:

Answer 35

1. Epidural dose in the subarachnoid space 2. Epidural dose in the subdural space 3. Single shot spinal after a failed epidural

Question 36

How can you rule out subdural catheter placement during an epidural placement?

Answer 36

You can't. It's just bad luck.

Question 37

How does a subdural epidural catheter placement manifest?

Answer 37

Within 10-25 min the patient will experience symptoms of a total spinal

Question 38

Why do subdural catheters result in higher sensory blocks?

Answer 38

Because its a very low volume space. An epidural dose will fill the entire space up to the cervical level

Question 39

What are the symptoms of a total spinal?

Answer 39

Dyspnea, difficulty phonating, hypotension, loss of consciousness from hypotension

Question 40

What is the initial treatment for a total spinal?

Answer 40

pressors, fluids, leg raise, uterine displacement

Question 41

What are some differential diagnoses for a total spinal?

Answer 41

Anaphylaxis, eclampsia, AFE

Question 42

Why is magnesium a smooth muscle relaxant?

Answer 42

It antagonizes calcium, interfering with muscle contraction and hyperpolarizing membranes in excitable tissues

Question 43

What is the first clinical sign of magnesium toxicity?

Answer 43

Loss of DTRs

Question 44

How does magnesium impact NMBA?

Answer 44

Potentiates them

Question 45

What are the initial treatments for hypermagnesemia?

Answer 45

Calcium gluconate Diuretics (to speed up excretion) Supportive Measures

Question 46

What is the second line uterotonic?

Answer 46

Methergine

Question 47

What is the third line uterotonic?

Answer 47

Hemabate

Question 48

What is the correct methergine dose?

Answer 48

0.2mg IM

Question 49

What is the correct dose of hemabate?

Answer 49

250mcg IM

Question 50

Which uterotonic should be avoided in asthmatics?

Answer 50

Hemabate A is for Asthma

Question 51

Which uterotonic causes diarrhea?

Answer 51

Hemabate

Question 52

What can happen if you give oxytocin too quickly?

Answer 52

CV Collapse

Question 53

What can happen if you give methergine IV?

Answer 53

Vasoconstriction, hypertension, cerebral hemorrhage

Question 54

What is another name for Hemabate?

Answer 54

Prostaglandin F2, Carboprost

Question 55

How does general anesthesia impact maternal mortality?

Answer 55

17x higher!!!!

Question 56

What are some situations where a general anesthetic is necessary for a C/S?

Answer 56

Hemorrhage Fetal Distress Coagulopathy Refusal of regional Contraindications to regional

Question 57

Does general anesthesia result in greater or less hemodynamic stability?

Answer 57

More stability than neuraxial

Question 58

Triple prophylaxis against aspiration includes which three drugs?

Answer 58

Bicitra (neutralizes gastric acid) Ranitidine (reduces gastric acid secretion) Reglan (increases emptying and LES tone)

Question 59

Does pregnancy increase or decrease the incidence of myalgia from Succinylcholine?

Answer 59

Decreases it. A defasciculating dose usually isn't needed

Question 60

Normal amniotic fluid volume is approximately:

Answer 60

700 ml

Question 61

What is the best gestational age to perform a non-obstetric surgery?

Answer 61

Ideally the 2nd trimester Less chance of teratogenicity than 1st T Less chance of PTLD than 3rd T

Question 62

What is a normal maternal PaCO2?

Answer 62

30

Question 63

How long after delivery should elective surgery be delayed?

Answer 63

2-6 weeks

Question 64

Define chronic hypertension

Answer 64

Occurs before 20 wks At risk of developing Pre-E

Question 65

Define gHTN

Answer 65

Develops after 20 wks with no s/s of pre-E

Question 66

When is proteinuria not required for a diagnosis of Pre-E?

Answer 66

Severe features: RUQ pain CNS s/s IUGR Thrombocytopenia Elevated Liver Enzymes

Question 67

What maternal age is most susceptible to pre-E?

Answer 67

<20 and >35

Question 68

On a molecular level, what is so different about a pre-E placenta vs a normal one?

Answer 68

Normal placentas produce thromboxane and prostacyclin in equal amounts Pre-E placentas produce 7x more thromboxane than prostacyclins

Question 69

An increase in thromboxane causes:

Answer 69

Increased Platelet Aggregation Vasoconstriction Increased uterine irritability Decreased placental blood flow

Question 70

What is the labetalol regimen for severe HTN?

Answer 70

20mg IV initially Then 40-80 mg q10min Max dose 220mg

Question 71

What is the hydralazine regimen for severe HTN?

Answer 71

5mg IV q20 min Max 20mg

Question 72

What is the Nifedipine regimen for mild hypertension?

Answer 72

10mg PO q20 min Max dose 50mg

Question 73

Patients with severe Pre-E have an exaggerated response to _______ and _______

Answer 73

sympathomimetics methergine

Question 74

How does magnesium protect end organs?

Answer 74

Fibrin deposits reduce organ perfusion. Magnesium decreases the rate of deposition

Question 75

What is Cocaine's MOA?

Answer 75

It inhibits NE reuptake in the synaptic cleft, increasing SNS tone throughout the body

Question 76

Cocaine is associated with what blood dyscrasia?

Answer 76

Low platelets

Question 77

Risks for uterine atony include:

Answer 77

Multiple gestation Pitocin use Multiparity Polyhydramnios

Question 78

DIC is associated with an increased incidence of:

Answer 78

AFE Abruption IUFD