Obstetrical Anesthesia Flashcards

1
Q

RSI, application of cricoid pressure, and a cuffed ETT is needed for pregnant women receiving general anesthesia after the __________.

A

first trimester

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are 3 lung capacities that do not change during pregnancy?

A

vital capacity, total lung capacity, and inspiratory capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Would you expect PaO2 to be higher in pregnant or non-pregnant state?

A

pregnant

*CO2 would be higher in the non-pregnant state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens to the diaphragm in pregnancy?

A

displaced cephalad about 4 cm by the expanding uterus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

An increase in oxygen consumption produces a ______% increase in alveolar ventilation at term.

A

70

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why do pregnant pt’s desat quickly?

A

they have a decreased FRC and increased alveolar ventilation resulting in faster desaturation
*an increased maternal oxygen consumption and any episodes of apnea will lead to maternal hypoxia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When is airway edema most evident?

A

airway edema d\t engorgement is most evident during the third trimester

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What central hemodynamics increase at term?

A
increase:
\+50% in CO
\+25% in SV
\+25% in HR
LVEDV
EF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What central hemodynamics decrease at term?

A

decrease:

-20% in SVR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens to CVP in the parturient at term?

A

no change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens to LVESV in the parturient at term?

A

no change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens to PCWP in the parturient at term?

A

no change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens to pulmonary artery diastolic pressure in the parturient at term?

A

no change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What two changes result in a dilutional anemia in the parturient at term?

A

a +45 % increase in blood volume, but another +55% in plasma volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a typical H&H in the parturient at term?

A

11.6/35.5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is maternal supine hypotensive syndrome?

A

compression of IVC decreases venous return and this will result in decreased SV and hypotension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is another name for maternal supine hypotensive syndrome?

A

aortocaval syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How can you treat maternal supine hypotensive syndrome?

A

LUD–> left side with wedge under right hip 15%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Blood flow to uterine vasculature is approximately _______.

A

700-800ml/minute

must keep maternal SBP >100mmHg to ensure perfusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why does the increase in blood volume not cause an increase in BP?

A

due to a decrease in peripheral vascular resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

A healthy parturient will tolerate up to _____ml of blood loss.

A

1500mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

A high Hgb of >14 can indicate a low volume state caused by ________. (3)

A

1) preeclampsia
2) HTN
3) inappropriate diuretics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why do women with cardiac and pulmonary disease remain at risk after delivery?

A

b\c CO remains high in the first few hours following postpartum (80%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Cardiac output during labor:

Latent Phase - increases ________%

A

15%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Cardiac output during labor:

Active Phase - increases ________%

A

30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Cardiac output during labor:

Second Stage - increases ________%

A

45%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Cardiac output during labor:

Postpartum - increases ________%

A

80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Always avoid aortocaval compression: _______% of supine parturients with a T4 sympathectomy develop significant hypotension.

A

70-80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What clotting factors increase at term?

A

1, 7, 8, 9, 10, 12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What clotting factors decrease at term?

A

11, 13 (thromboplastin and fibrin stabilizing factor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What happens to LES tone and gastric emptying during pregnancy? What causes this change?

A

decreased; d\t circulating progesterone

*also decreased GI motility, food absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Elevated _____ from the placenta increases intragastric pressure, making the patient prone to ______.

A

gastrin; reflux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What do narcotics, valium, and atropine d\t LES tone and gastric emptying time?

A

decrease LES tone and prolong gastric emptying time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

_________ increases LES tone and increases gastric emptying.

A

metoclopramide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What happens to BUN and creatinine during normal maternal changes?

A

decreased d\t increases in renal blood flow and GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What happens to renal blood flow and GFR by the fourth month of gestation?

A

increases by 50-60%, but slowly returns to normal during third trimester; GFR remains elevated until delivery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Describe how maternal blood circulates through the placenta.

A

maternal blood is carried initially in the uterine arteries—> blood is spurted into intervillous space—> blood in this space passes fetal villi before draining back to veins of the uterine wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How many microscopic layers are found in the placental membrane?

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

General Anesthesia Changes During Pregnancy:

MAC is reduced by ______.

A

15-40%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

General Anesthesia Changes During Pregnancy:

What are some considerations for ETT choice and intubation?

A

use small tube, aspiration risk, RSI, cricoid, engorgement, increased risk of failed intubation, increased MV required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Regional Anesthesia Changes During Pregnancy:

The curvature of the spine is the parturient is increased and termed as ______.

A

lumbar lordosis is increased

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Regional Anesthesia Changes During Pregnancy:

Does subarachnoid dosing change for the parturient?

A

reduce subarachnoid dose by 25%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Regional Anesthesia Changes During Pregnancy:

Does epidural dosing change for the parturient?

A
epidural dose (large dose) unaltered
epidural dose (small dose) reduced
44
Q

Name 3 things that result in an increase in uterine blood flow.

A

1) pain relief
2) decreased sympathetic activity; no pain
3) decreased maternal hyperventilation; no pain

45
Q

Name 3 things that result in an decrease in uterine blood flow.

A

1) hypotension (maternal SBP <100)
2) unintentional IV injection of local anesthetic and/or EPI
3) absorbed local anesthetic (little effect)

46
Q

What is the first stage of labor?

A

from onset of contractions to complete dilation of the cervix
1) latent- little dilation of cervix, but becomes softer
2) active- regular cervical dilation
pain T10-L1—-> “First Four”

47
Q

What is the second stage of labor?

A

begins at full cervical dilation (10cm) and ends with delivery of infant
pain T10-S4 dermatomes–> “Second Sacrum”

48
Q

What signals the start of the second stage of labor?

A

onset of perineal pain at the end of the first stage of labor is the signal of fetal descent and the beginning of the second stage

49
Q

Sensory innervation of the perineum is provided by the ______ nerve (S2-S4).

A

pudendal nerve

50
Q

What is the third stage of delivery?

A

delivery of the placenta

51
Q

What is the most commonly used opioid for parturients?

A

meperidine 10-25mg IV or 25-50mg IM

52
Q

This drug is most useful prior to delivery or as an adjunct to regional anesthesia.

A

ketamine 10-15mg IV with good analgesia in 2-5min

53
Q

Why are NSAIDs such as Ketorolac not recommended for the parturient?

A

d\t suppression of uterine contractions; promotes closure of fetal ductus arteriosus

54
Q

What are benzodiazepines not recommended for the parturient?

A

strong potential to cause prolonged neonatal depression

55
Q

What are 3 advantages of spinal opioids?

A

1) preservative free
2) useful in high risk patients
3) they do not impair mom from pushing the baby out

56
Q

What are 3 disadvantages to spinal opioids?

A

1) less complete analgesia
2) lack of perineal relaxation
3) pruritus, nausea, vomiting, sedation, and respiratory depression

57
Q

What is the most common side effect of regional anesthesia?

A

hypotension= 20-30% decline in BP or a SBP <100

58
Q

What is the most common cause of hypotension in regional anesthesia?

A

d\t decreased sympathetic tone with aortocaval compression in the upright position

59
Q

What is the treatment for hypotension associated with regional anesthesia?

A

1) ephedrine boluses (25-50mg)
2) oxygen
3) LUD
4) IV fluids
* small doses of phenylephrine (25-50mcg) may also be used

60
Q

Regional Anesthesia:

What do you do in the event of an unintentional IV injection?

A

1) avoid head up position
2) LUD
3) treat seizures if manifested (thio, prop, midaz)
4) Bupivacaine induced cardio collapse can be treated with 20% intralipid 1.2-2ml/kg
5) intubate and ventilate

61
Q

Regional Anesthesia:

What do you do in the event of an unintentional intrathecal injection?

A

1) supine with LUD
2) treat hypotension with ephedrine and fluids
3) high spinal may need intubation

62
Q

Regional Anesthesia:

What do you do in the event of a PDPH with mild h\a?

A

1) bed rest
2) hydration
3) oral analgesics
4) epidural saline injection (50-100ml)
5) caffeine sodium benzoate (500mg)

63
Q

Regional Anesthesia:

What do you do in the event of a PDPH with moderate to severe h\a?

A

1) epidural blood patch (10-30cc)

2) prophylactic EBP not recommended

64
Q

What is considered to be nonreassuring fetal heart rate patterns?

A

1) repetitive LATE decelerations
2) loss of beat-to-beat variability
3) sustained FHR <80

65
Q

What are signs of fetal distress?

A
  • NRFHT’s
    1) repetitive LATE decelerations
    2) loss of beat-to-beat variability
    3) sustained FHR <7.20
  • meconium stained amniotic fluid
  • oligohydramnios (too little fluid)
  • intrauterine growth restriction
66
Q

What 4 P’s go with placenta previa?

A

P-painless vaginal bleeding (2nd or 3rd tri)
P-Preterm bleeding
P-Planned (known about it in most cases)
P-Pass on pushing

67
Q

When do fetal lungs mature?

A

37 weeks

68
Q

What is the initial treatment for placental previa?

A

bedrest and observation

*avoid vaginal exams–> placenta is covering vaginal opening

69
Q

What is the goal for placental previa?

A

delay the delivery until the fetus is mature–> c-section (urgency based on maternal hypotension)

70
Q

When is the first episode of bleeding for placenta previa?

A

usually preterm and there are no contractions with the bleeding

71
Q

_______ lying placenta previa increases the risk of excessive bleeding for c-section.

A

anterior

72
Q

What can be used for confirmation of diagnosis of placenta previa?

A

ultrasonography

73
Q

What is placental abruption?

A

like an O2 tank getting ripped off a scuba divers back–> separation of the placenta from the deciduas basalis before delivery of the fetus—> acute bleeding, which is often hidden

74
Q

What is the cause for fetal distress with placental abruption?

A

loss of area for maternal fetal gas exchange–> late decels

75
Q

What is the classic presentation of placental abruption?

A

1) painful bleeding
2) uterine tenderness
3) increased uterine activity
4) atypical presentation

76
Q

With a placental abruption, the uterus can contain up to how much blood?

A

2500mL

77
Q

What are some risk factors for placental abruption?

A

1) HTN
2) advanced age
3) parity
4) tobacco or cocaine use
5) trauma
* so basically vascular paths

78
Q

Is regional more appropriate with placental previa or abruption?

A

PREVIA…. but still based on patient

NO REGIONAL FOR ABRUPTION (coagulopathy and uncertain uteroplacental BF)

79
Q

What is the treatment for placental abruption?

A

NO DELAYS–> continued placental separation may lead to fetal death

80
Q

What is the etiology of placental abruption?

A

unknown

81
Q

What are the 3 abnormal placental implantation defects?

A

1) Placenta Accreta Vera
2) Placenta Increta
3) Placenta Percreta

82
Q

List the 3 abnormal placental implantation defects in order from most to least prevalent?

A

1) Placenta Accreta Vera 78%
2) Placenta Increta 17%
3) Placenta Percreta 5%

83
Q

What is Placenta Accreta Vera?

A

ADHERES to the myometrium without invasion of or passage through the uterine muscle

84
Q

What is Placenta Increta?

A

INVADES and is confined to the myometrium

85
Q

What is Placenta Percreta?

A

invades and may PENETRATE the myometrium, the uterine serosa, or other pelvic structures

86
Q

KNOW

A

PREVIA– playing peek a boo
ABRUPTION– there’s an “abruption” that is… “eruption” of blood

IMPLANTATION DEFECTS= AIP (accreta, increta, percreta)
Adhere, INVADE, and PROTRUDE the myometrium

87
Q

If mom has had a placenta previa, previous c-section or had uterine trauma, she is at risk for developing _______.

A

placenta accreta

88
Q

State whether regional anesthesia in a parturient with one of the following is wise:

  • mitral valve disease
  • aortic insufficiency
  • congenital lesions with left to right shunting
A

yes its fine—> decreased preload, decreased afterload, reduced pulmonary congestion…. together the above may increase CO

89
Q

State whether regional anesthesia in a parturient with one of the following is wise:

  • aortic stenosis
  • congenital lesions with right to left shunting
  • primary pulmonary HTN
A

regional anesthesia is detrimental–> the decreased preload and afterload are detrimental
-best managed with intraspinal opioids alone, systemic medications, pudendal nerve blocks, and possibly general anesthesia

90
Q

What is pre-eclampsia?

A

syndrome of HTN, proteinuria, and generalized edema occurring after the 20th week of gestation

91
Q

What is eclampsia?

A

occurrence of convulsions superimposed on pre-eclampsia

92
Q

What do you give for pre-eclampsia?

A

magnesium is for pre-eclampsia–> attenuates smooth muscle contraction by competing with calcium at the cell membrane level and preventing an increase in free intracellular calcium
*tocolysis–> improves uterine BF and antagonizes uterine hyperactivity (but this also prolongs labor and increases postpartum hemorrhage)

93
Q

What is the normal plasma level of Magnesium?

A

1.5-2

94
Q

What is the therapeutic plasma level of Magnesium for pre-eclampsia?

A

4.0-8.0

95
Q

What are the neonatal effects of magnesium administration?

A
  • lower APGAR scores

- decreased muscle tone (only with maternal overdose)

96
Q

What type of deceleration is seen with cord compression?

A

variable decels

97
Q

What type of deceleration is normal and results from head compression or stretching of neck during uterine contractions (vagal stimulation)?

A

early decels (Type I)

98
Q

What type of deceleration is caused from uteroplacental insufficiency and fetal compromise with a decrease in HR?

A

late decels (Type II)

99
Q

What position should be avoided in the parturient?

A

supine

100
Q

This level of block is needed to be secured for a c-section.

A

T4

101
Q

Is hyperglycemia a problem associated with infant prematurity?

A

No…. but the following is:

1) hypoglycemia
2) respiratory distress
3) hypocalcemia
4) hyperbilirubinemia

102
Q

Which of the following is not a cause of neonatal depression at birth?

a) maternal HTN
b) trauma
c) drugs
d) prematurity

A

TRAUMA is not a cause

103
Q

Is normal delivery of the placenta a common cause of postpartum hemorrhage?

A

No

104
Q

What level of neural blockade is required for optimal anesthesia during the second stage of labor?

A

T10-S4

105
Q

How much of the total uterine blood flow goes into the intervillous space (ml/min)?

A

550ml