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Flashcards in Obstetrics Deck (86):
1

Preeclampsia risk factors (6)

Hydatidiform mole, multiple gestational, obesity, polyhydramnios, diabetes, primigravidas

2

Define mild preeclampsia

Systolic > 140, diastolic > 90, proteinuria >2 gm/day, edema

3

What vasopressor should be used with mag toxicity and why?

Ephedrine, magnesium antagonizes the effects of alpha agonists

4

What happens to cardiac output at term, during labor, and immediately after delivery?

40% increase at term, 45% during labor, 60-80% increase following delivery

5

How much does plasma volume increase? Red cell volume?

40% plasma, 20% red cell volume

6

During pregnancy, what H&H signifies true anemia?

7

What 3 changes happen to the GI system during pregnancy?

Acidity and gastric volume increase, gastric motility decrease (2/2 progesterone), GE sphincter tone decreases

8

When does aortocaval compression occur?

20 weeks

9

What happens in supine position after 20 weeks and why?

Aortocaval compression 2/2 a 50% increase in femoral venous pressure that causes a 10-15% decrease in SV and CO

10

During pregnancy, when is the H&H lowest and why?

30-34 weeks 2/2 plateau in volume expansion

11

What changes happen to RBF, GFR, and BUN/Cr? When?

They increase by 50% leading to a decrease in BUN and creatinine; 16 weeks

12

What happens to total protein and albumin/globulin ratio during pregnancy and its importance

Decreased; lower albumin may result in higher free blood levels of substances

13

Why happens to pseudocholinesterase levels during pregnancy? Does this affect your anesthetic?

Decreased, response to moderate doses of succinylcholine is not prolonged

14

What happens to SV, HR, and SVR during pregnancy?

SV increases by 25%, HR increases less, SVR decreases by 20%

15

What CNS changes occur during pregnancy?

40% decrease in MAC, 30-50% decrease in local requirements

16

What 3 changes occur to the airway during pregnancy?

Capillary swelling leads to mucosal enlargement, tissues become more friable, breast enlargement can cause head positioning difficulty

17

What happens to minute ventilation during pregnancy and why?

Increases by 50%; progesterone increased tidal volume with little change in RR

18

What acid/base changes occur during pregnancy?

PaCO2 is ~32 but pH is unchanged because of compensatory metabolic acidosis (HCO3 25 --> 21)

19

How does inhalational induction change during pregnancy and why?

Increased ratio of minute ventilation to FRC causes rapid induction and emergence

20

What happens to FRC during pregnancy?

Decreases 20% due to decrease in residual volume; closing capacity exceeds FRC in ~50% of supine women late in pregnancy

21

What happens to vital capacity during pregnancy?

Unchanged as inspiratory capacity increases and expiratory reserve volume decreases

22

What happens to PaO2 during pregnancy?

Increases by 10

23

What happens to airway resistance during pregnancy?

Decreases 2/2 progesterone

24

What happens to tidal volume during pregnancy?

Increase by 45%

25

What happens to oxygen consumption and CO2 production during pregnancy?

Consumption increase 30-40%, CO2 production increase 30-40%

26

What coagulation factors increase during pregnancy?

Factors I (fibrinogen), II, VII, VIII, IX, X

27

What is the range for leukocytosis after 12 weeks?

10500-16000

28

Which coagulation factors decrease during pregnancy?

Factors XI, XIII

29

What is the non-pregnant UBF?

50-200 ml/min

30

What is pregnant UBF?

10% of CO, 600-700 ml/min

31

How much must UBF decrease to see fetal distress?

50%

32

Name drugs that do not cross the placenta (5)

heparin, insulin, glycopyrrolate, non-depolarizing relaxants, succinylcholine

33

What is the 1st stage of labor?

start of contractions to complete cervical dilation

34

What nerves are involved in 1st stage of labor and what do they innervate?

T10-L1 visceral pain of contractions and cervical dilation --> uterus, cervix, upper vagina

35

What is the 2nd stage of labor

complete cervical dilation up until delivery

36

What nerves are involved in the 2nd stage of labor and what do they innervate?

S2-S4 (pudendal) somatic pain of distention of birth canal, vulva, and perineum--> perineal area

37

What are the complications associated with paracervical block, what is the incidence, and when can it be used?

10-40% of fetal bradycardia and acidosis because high fetal blood levels cause cardiotoxicity; can be used in 1st stage of labor

38

What are aortocaval compression symptoms?

n/v, tachycardia, hypotension, sweating; may not have symptoms if uterine artery hypoperfusion and hypotension is present without compromise of maternal CO

39

What is frank/complete/incomplete breech?

buttocks presenting, buttocks and feet presenting, one or both feet presenting

40

Breech presentation increases maternal risk of...

maternal mortality 2/2 hemorrhage, infection, and retained placenta

41

Breech presentation increases risks to fetus...

asphyxia due to cord compression and intracranial hemorrhage due to trauma

42

Define severe preeclampsia

>/= 160/110, >5 gm proteinurea/day, edema (can include pulmonary edema leading to CHF)

43

What are the characteristics of eclampsia?

Hypovolemia, thrombocytopenia, DIC, CNS changes

44

What CNS changes can be seen with eclampsia?

Convulsions, coma, hypoxic cerebral encephalopathy

45

When does preeclampsia present and end?

24 weeks and ends within 48 hours of delivery

46

What is the treatment for preeclampsia?

3-5 gm loading dose of magnesium given over 15 min and 1gm/hr maintenance

47

What is the magnesium goal for preeclampsia treatment?

4-6 mEq/L

48

What are magnesium side effects?

Skeletal muscle relaxation, anticonvulsant, sedation, tocolytic, vasodilator

49

What does magnesium cause skeletal muscle relaxation?

It decreases the release of acetylcholine and decreases the sensitivity of the motor end plate to acetylcholine

50

What are the magnesium side effects for the infant?

Flaccidity, respiratory depression, apnea

51

How does magnesium treatment change your anesthetic

Increased sensitivity to depolarizing and non-depolarizing relaxants; decrease succinylcholine does by 50%

52

How is preeclampsia treated?

Bed rest, magnesium, hydralazine

53

Benefits of hydralazine vs SNP for treatment of preeclampsia

Hydralazine increases uterine and renal blood flow, starts to work in 15-20 min, lasts for 2 hours; SNP decreases uterine blood flow and increases risk of fetal CN toxicity (crosses placenta)

54

What is placenta previa and what is the incidence?

When the placenta is located over or very near the internal cervical os; 0.1%-1.0% incidence that increases with age

55

What is abruptio placenta and what is the presentation?

Separation of placenta from uterine wall after 20 weeks; presents as hypotension and fetal distress

56

What are the symptoms of uterine rupture?

Severe abdominal pain, hypotension, loss of fetal heart tones

57

Risk factors for uterine atony (4)

Retained placenta, multiparity, large infants, polyhydramnios

58

What is the treatment for uterine atony?

Uterine massage, oxytocin, prostaglandin F2-alpha, ergots, misoprostol, hysterectomy with ligation of internal iliac artery

59

What is placenta acreta?

Abnormal adherence of placenta to myometrium

60

What are the risks to fetus with benzodiazepines and nitrous?

Cleft palate; inhibits methionine synthetase impairing DNA synthesis

61

What is ritodrine/terbutaline? Uses? Side effects?

Beta agonists used for tocolysis; increased HR and CO (b1) & hyperglycemia and hypotension (b2) also causes pulmonary edema, hypokalemia, arrhyhmias

62

Why is ethanol used during pregnancy? What is its use associated with?

It's a tocolytic that works by inhibiting oxytocin; increases the risk of gastric aspiration; administered in D5W

63

What side effect is ritodrine and magnesium use associated with?

Chest pain

64

What is prostaglandin synthetase used for? Side effects?

Used for tocolysis; can cause premature closure of PDA, primary pulmonary HTN, and inhibits cyclooxygenase which may lead to bleeding problems

65

What is normal FHR variability and what does it indicate?

Normal variability is 7-14 beats/min; it is best indication of fetal well being --> absence happens with prematurity,sleeping baby, CNS damage, hypoxia, drug effects

66

Early deceleration

FHR slowing begins at onset of contraction and ends at the conclusion, caused by fetal head compression leading to bagel stimulation, benign

67

Late deceleration

FHR dip starts after onset if contraction an persists after he conclusion, indicate uteroplacental insufficiency

68

Variable deceleration

FHR dips not associated with contractions, due to umbilical cord compression, if last more than 1 minute indicative of severe fetal acidosis with imminent in utero death

69

What is scalp pH normal range?

7.20-7.25

70

When and how is L/S ratio helpful?

L/S ratio is = until 35 weeks, if L/S ratio is >/= 2 respiratory distress syndrome is unlikely

71

APGAR

A - appearance, P - pulse, G - grimace, A - activity, R - respirations

72

Most common nerve injury during pregnancy and symptoms

Common peroneal nerve compressed between head of fibula and stirrups; foot drop, loss of extension of toes, loss of eversion

73

Mechanism of sciatic nerve injury during labor and symptoms

External rotation of legs (distance between sciatic notch and fibula is increased); decreased strength in muscles below the knee and decreased sensation of lateral 1/2 of leg and all foot except arch

74

Mechanism of femoral nerve injury during labor and symptoms

Excessive angulation of thigh; unable to flex the hip or extend the knee, decreased sensation to superior aspect of thigh and antero-medial aspect of leg

75

What drugs increase/decrease FHR variability?

Increase - ephedrine; decrease with fetal CNS depressants (benzos, barbs, opioids, anesthetics) and block parasympathetic (atropine)

76

Define "ion trapping"

If the fetus becomes acidotic local anesthetic (weak bases) gets trapped in the ionized form on the fetal side

77

With a maternal PaO2 of 600 mm Hg what will the fetal PaO2 be?

No more than 50 mm Hg

78

How much will an FiO2 of 21% --> 100% change the venous O2? Arterial O2?

Umbilical venous 28 --> 47, umbilical arterial 15 --> 25

79

Pathophysiology of preeclampsia

Thromboxane over production causes vasoconstriction, platelet aggregation, increased uterine activity and impaired uteroplacental blood flow; uterine ischemia causes release of renin which promotes angiotensinogen to angiotensin I

80

Drugs increasing uterine tone (5)

PGF2 alpha, ergots, oxytocin, ketamine, amide local anesthetics

81

Drugs that decrease uterine tone (5)

Beta 2 agonists, ethanol, magnesium, methylxanthines, potent anesthetics

82

Incidence of PDPH

40-50% in the first week PP

83

Modalities for diagnosing central venous thrombosis

MRV/CTV

84

PDPH risk factors

Young, female, pregnant, non-smoker, dural thickness

85

PDPH conservative treatment

Caffeine (increase CSF production and vasoconstricts), theophylline, hydrocortisone, gabapentin

86

Full stomach

12 weeks