OB Flashcards
1
Q
Lung Patho: the gravid uterus shifts the diaphragm cephalad. What 3 things does this do?
A
FRC reduced (d/t decreased ERV and RV)
Increased O2 consumption with decreased FRC = hastens hypoxemia
FRC falls below closing capacity = airway closure during TV breathing
2
Q
Progesterone is a respiratory
A
stimulant
3
Q
What does progesterone do to minute ventilation?
A
MV increased up to 50% = moms PaCO2 falls and developed respiratory alkalosis. Renal compensation to normalize bicarb.
4
Q
ABG: pH PaO2 PaCO2 HCO3
A
pH - no change
PaO2 - increase (104-108)
PaCO2 - decrease (28-32)
HCO3 - decrease (20)
5
Q
How does the oxyHGB dissociation curve change with pregnancy?
A
shifts to the right (increased P50)
facilitates O2 transfer to fetus
6
Q
Minute ventilation = TV X RR
how to each change?
A
MV - Increased by 50%
TV - Increased by 40%
RR - increased by 10%
7
Q
Lung Volumes:
TLC
A
decreased (5%)
8
Q
Lung Volumes:
Vital capacity
A
No change
VC = TV + ERV + IRV
9
Q
Lung Volumes:
FRC
A
Decreased (20%)
diaphragm compresses lungs
10
Q
Lung Volumes:
ERV
A
Decreased (20-30%)
11
Q
Lung Volumes:
Residual volume
A
Decreased (15-20%)
12
Q
Lung Volumes:
Closing capacity
A
No change
13
Q
O2 consumption @
- TERM
- 1st stage labor
- 2nd stage labor
A
- TERM - increased 20%
- 1st stage - increased 40%
- 2nd stage - increased 75%
14
Q
What happens to mallampati score
A
increases d/t vascular engorgement and soft tissue edema
15
Q
CV O2 consumption
A
increases 20%
16
Q
CO = HR X SV
CO -
A
CO - increases 40%
Uterus receives 10% CO
Uterine contraction causes autotransfusion/increased preload
17
Q
CO = HR X SV
HR
A
Increased 15%
18
Q
CO = HR X SV
SV
A
increased 30%
19
Q
Compared to prelabor values, CO during labor
1st stage
2nd stage
3rd stage
A
1st stage - increased 20%
2nd stage - increased 50%
3rd stage - increased 80%
20
Q
CO returns to preLABOR values in ______
CO returns to prePREGNANCY values in ______
A
24-48 hours
~2 weeks
21
Q
Blood Pressure
MAP
SBP
DBP
A
MAP - no change
SBP - no change
DBP - decreased
22
Q
SVR
A
decrease 15%
progesterone causes vascular muscle relaxation
23
Q
PVR
A
Decrease 30%
progesterone causes vascular muscle relaxation
24
Q
Filling pressures
CVP
PAOP
A
CVP - no change
PAOP - no change
25
How does the cardiac axis change?
left deviation
gravid uterus pushes diaphragm cephalad and heart pushed up/left
26
intravascular fluid volume
- plasma volume
- erythrocyte volume
intravascular fluid volume - increased 35%
plasma - increased 45%
erythrocyte - increased 20%
(creates dilution anemia)
27
Clotting factors that are increased
I, VII, VIII, IX, X, XII
pregnancy creates hypercoaguable state
28
Anticoagulants that are decreased
C & S
DVT 6X more likely
29
Fibrinolytics that are increased
increased fibrin breakdown
| counteracts hypercoagulability
30
Anti-fibrinolytics that are decreased
XI and XIII
31
How does MAC change?
Decreased 30-40%
| begins at 8-12 weeks
32
How does sensitivity to LAs change?
Increased
| d/t increased progesterone
33
How does epidural vein volume change?
Decreased
| decrease volume of subarachnoid space and epidural space - compressive effect
34
How does ICP change?
No change
35
How does gastric volume change?
Increased
give H2 receptor blocker to decrease volume --> ranitidine
(d/t increased gastrin)
36
How does gastric pH change
Decreased
this means more acidic --> give citrate
(d/t increased gastrin)
37
How does LES tone change?
Decreased
reglan increases LES
(d/t increased progesterone, estrogen and cephalad displacement of diaphragm)
38
How does gastric emptying change?
No change before onset of labor, DECREASED after labor begins
reglan hastens gastric emptying
39
How does GFR change?
Increased
| d/t increased blood volume and CO
40
How does creatine clearance change?
Increased
| d/t increased blood volume and CO
41
How does glucose in urine change?
Increased
| d/t increased GFR and decreased renal absorption
42
How does Cr and BUN change?
Decreased
| d/t increased CrCl
--> if Cr and BUN are unchanged, they are actually elevated
43
How does uterine blood flow change?
Increased
| 500-700 ml/min
10% CO
44
How does serum albumin change?
Decreased
| = increased free fraction of highly protein bound drugs
45
How does pseudocholinesterase change?
Decreased
| no meaningful effects of Succs on metabolism
46
What are the drug characteristics that favor placental transfer
low molecular weight (<500 daltons)
most anesthetic drugs are <500 daltons
47
Drugs with significant placental transfer
```
LAs (except chloroprocaine)
IV anesthetics
Volatile Anesthetics
Opioids
Benzos
Atropine
Beta-blockers
Mag (no lipophilic but its small)
```
48
Drugs with no placental transfer
NMBs
Heparin
Insulin
Glyco
49
What is stage 1 of labor
Beginning of regular contractions to full cervical dilation (10cm)
50
What is stage 2 of labor
Full cervical dilation (10cm) to delivery of fetus
Pain in perineum begins during stage 2
51
What is stage 3 of labor
Delivery of placenta
52
Active and latent phase are part of which stage?
Stage 1
Latent phase - 2-3 cm dilated
Active phase full dilation
53
What are NPO guidelines during labor
Drink moderate amount of clear liquids throughout labor
Eat solid foods until neuraxial block is placed
54
1st stage of labor pain begins where? Which nerve roots?
Pain begins in lower uterine segment and cervix
T10-L1 posterior nerve roots
55
1st stage of labor pain afferent pathway --> starts in what fibers and goes where?
visceral C fibers --> hypogastric plexus
| dull, diffuse, cramping pain
56
Regions techniques for 1st stage labor pain
Neuraxial (spinal, epidural, CSE)
Paravertebral lumbar sympathetic block
Paracervical block
57
What is the risk with paracervical blocks?
high risk of fetal bradycardia!
58
2nd stage pain adds pain impulses from where?
Vagina, perineum, pelvic floor
59
2nd stage pain impulses travel from perineum to which nerve roots?
S2-S4 posterior nerve roots
| sharp, well localized pain
60
Regions techniques for 2nd stage labor pain
Neuraxial (spinal, epidural, CSE)
Pudendal nerve block
61
Normal Fetal HR
- Fetal causes
- Maternal causes
110-160
Fetal: Intact CNS/ANS & normal acid base balance
Maternal: normal uteroplacent blood flow
62
Bradycardic Fetal HR
- Fetal causes
- Maternal causes
<110
Fetal: Asphyxia & Acidosis
Maternal: Hypoxia & drugs that reduce placental blood flow
63
Tachycardic Fetal HR
- Fetal causes
- Maternal causes
>160
Fetal: hypoxia & arrhythmias
Maternal: Fever, Chorioamnionitis, Atropine, Ephedrine, Terbuterline
64
Evaluation of FHR
| Category 1
- Baseline HR 110-160
- Moderate variability
- Accelerations absent or present
- Early decels absent or present
- NO late or variable decels
65
Evaluation of FHR
| Category 2
- Bradycardia w/o absence of baseline FHR variability
- Tachycardia
- Variable variability
- Absent/minimal acceleration with fetal stimulation
- Recurrent variable decels
66
Evaluation of FHR
| Category 3
- Bradycardia
- Absent baseline variability
- Recurrent late decels
- Recurrent variable decels
- Sinusoidal pattern
67
Complications of premature delivery
```
Resp distress syndrome
Intraventricular hemorrhage
NEC
HYPOglycemia
HYPOcalcemia
Hyperbilirubinemia
```
68
What drug is given to hasten fetal lung maturity and when does it begin to work
betamethasone
begins to take effect within 18 hours and peak benefit at 48 hours
69
What is a tocolytic and what are some examples
Used to delay labor by suppressing uterine contractions up to 24-48 hours (provide bridge to allow corticosteroids to work)
Beta 2 agonists
mag
Ca Channel blockers
Nitric oxide donors
70
What are examples of beta 2 agonists
ritodrine and terbutaline
71
What are side effects of beta 2 agonists
Hyperglycemia (mother)
Hypoglycemia (infant)
Hypokalemia
Can cross placenta and increase FHR
72
What patient population should you use mag cautiously in?
kidneys eliminate mag, so caution in renal insufficiency
73
What is the first sign of mag toxicity?
If deep tendon reflexes are present - risk of toxicity is low
Deep tendon reflexes are the first sign of mag toxicity
74
What is the normal mag level
1.8-2.5 mg/dL
75
Hypomag symptoms
<1.2
Tentany, seizure, dysrhythmia
1.2-1.8
neuromuscular irritability, hypokalemia, hypocalcemia
76
What mag level typically has no symptoms
2.5-5 mg/dL
77
symptoms of mag level 5-7 mg/dL
Diminished deep tendon reflexes
lethargy/drowsiness
flushing
N/V
78
symptoms of mag level 7-12 mg/dL
Loss deep tendon reflexes
hypotension
EKG changes
somnolence
79
symptoms of mag level >12 mg/dL
```
Resp depression --> apnea
complete heart block
cardiac arrest
coma
paralysis
```
80
Side effects of mag toxicity
Pulmonary edema
hypotension
skeletal muscle weakness (potentials NMB)
CNS depression
Reduced response to ephedrine and phenylephrine
81
What is the first line agent for tocolysis
PO nifedipine
82
Co-admin of nifedipine with what other agent can contribute to skeletal muscle weakness
magnesium
83
what mag level is considered tocolysis
4-8 mg/dL
84
What are uterotonic drugs used for? what are examples
stimulate uterine contraction
Oxytocin
Methergine (ergot alkaloid)
Prostaglandin F2
85
indicators for use of oxytocin/pitocin
to induce or augment labor, stimulate uterine contraction, combat uterine hypotonia or hemorrhage
86
when do you admin oxytocin
during c/s, admin after delivery of placenta
87
side effects of oxytocin
water retention, hyponatremia, hypotension, reflex tachycardia, coronary vasoconstricton
88
Methergine (ergot alkaloid) is a second line uterotonic, what is the dose & how is it administered
0.2mg IM
| IV admin can cause significant vasoconstriction, HTN and cerebral vasoconstriction
89
Prostaglandin F2 is a 3rd line uterotonic, what is the dose & how is it administered
250mcg IM or injected into uterus
90
Side effects of prostaglandin F2
N/V
Diarrhea
Hyper or hypotension
91
ideally, nonobstretical surgery is delayed until _____ weeks after delivers. Otherwise, when is the best time to perform surgery in the pregnant patient
2-6 weeks
second trimester
92
Why should you avoid NSAIDs in the pregnant patient?
they may close the ductus arteriosis
93
What the difference between gestation HTN, pre-eclampsia, and eclampsia
Gestational HTN
- occurs after 20 weeks
- HTN
Pre-eclampsia
- occurs after 20 weeks
- HTN
- protenuria
- edema
Eclampsia
- occurs after 20 weeks
- HTN
- protenuria
- edema
- Seizures
94
A healthy placenta produces thromboxane and prostacyclin in equal amounts, however, the pre-eclamptic patient produces 7X more ____
more thromboxane than prostacyclin
thromboxane favors increased vasoconstriction, platelet aggregation, uterine activity
&
decreased uteroplacental blood flow
95
What is SBP and DBP for mild and severe disease
mild
= 160
= 110
severe
>/= 160
>/=110
no need to medicate with antihypertensives until BP > 160/110
96
What is the preferred anesthetic management for the pre-eclamptic patient
neuraxial anesthesia assists with BP control and provided better uteroplacental perfusion. BE SURE TO RULE OUT THROMBOCYTOPENIA (<100,000)
97
maternal cocaine use will cause HTN, what is best choice for treatment
labetalol (Blocks alpha and beta - NEED BOTH)
Vasodilators
98
hypotension from maternal cocaine use will not respond to _____, what should be used instead?
ephedrine (becuase this is indirect acting - dependent on catecholamine stores, which are depleted)
give phenylephrine
99
What is chronic cocaine use associated with?
thrombocytopenia
100
With placenta accreta, increata, and percreta - what is the preferred anesthetic technique
although RA is safe, GA is preferred
101
APGAR Score
normal
moderate distress
impending demise
APGAR Score
normal: 8-10
moderate distress: 4-7
impending demise: 0-3
102
KNOW HOW TO CALCULATE AN APGAR SCORE
look at chart (all pretty easy to figure out..)
HR >100 = 2
HR<100 = 1
HR absent = 0
103
Newborn HR, RR , SPO2
HR 120-160 (HR <60 = CPR)
RR 30-60
SPO2 immediately after delivery is 60% and should rise to 90 after 10 min
