E2 OB Flashcards by Sara Knight

Define the following terms
Parturient
Gravida/Para
FHT/FHR

Parturient=pregnant patient
Gravida=number of times parturient has been pregnant
Para=number of times parturient has delivered
FHT/FHR=fetal heart tones/rate

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Define the following terms
1st stage labor
2nd stage labor
3rd stage labor

1st stage:
Begins-w/ onset of true labor (regular contractions)
Ends-when 10 cm dilated

2nd stage:
Begins-when 10 cm dilated (complete)
Ends-when fetus delivered

3rd stage:
Begins-when fetus delivered
Ends-with delivery of placenta

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Describe changes to heart size

Ventricular hypertrophy (ECCENTRIC)
By term--50% INC in LV mass

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How can INC LV mass affect the parturient CV physiology

DEC LV compliance affects LV fxn

Can DEC diastolic filling rate

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Describe diastolic changes in the parturient

Dysfxn causes INC dependence on ATRIAL contraction for VENT filling

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What can previous heart problems contribute to during pregnancy

Thromboembolism
PIH
HELPP
Amniotic fluid embolism

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Describe how the location of the heart is affected by pregnancy?
How can this present on EKG?
How does this affect PMI?

SHIFTED:
ANTERIOR & LEFT

EKG:
Left axis deviation
-QRS in V1 positive
-QRS in aVF negative

PMI:
Displaced CEPHALAD & LEFT
To 4th ICS & midclav line
-NORM = 5th ICS & MCL

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How is the first heart sound affected by pregnancy

Exaggerated splitting of mitral & tricuspid valve (more fluid)

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How is the 3rd HS affected by pregnancy and why?

Can be heard in THIRD trimester
Ventricular gallop
Result of INC vent size
-INC BV
-INC contraction force
-INC stretch

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How is the 4th HS affected by pregnancy?

disappears at term

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What are normal HS for TERM gestation parturient

1st, 2nd, 3rd
-NO 4th HS at term
Systolic ejection murmur

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Describe the pregnancy related heart murmur and cause

Grade II SEM @ upper sternal border & right side of heart
-benign
Cause = INC BV & flow through valve

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What types of valve problems are common in parturient

Tricuspid & pulmonic regurg
Mitral regurg (less common)

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How does pregnancy affect a pre-existing murmur from AV/MV regurg

-Intensity will DEC d/t DEC SVR

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How can phenylephrine affect a pre-existing murmur during pregnancy

Can INC intensity of murmur

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How does the development of PIH affect pre-existing murmur from AVR/MVR

INC intensity

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How does pregnancy affect a pre-existing murmur from AS & why

INC intensity

-d/t INC FLOW through stenotic valve

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What are normal QRS EKG variants during pregnancy
During 1st trimester
During 3rd trimester

QRS axis shift
1st trimester = RIGHTWARD (QRS negative in lead I)
3rd trimester = LEFTWARD
(QRS in V1 positive; QRS in aVF negative)

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What are ST-T wave EKG variants during pregnancy?
Why?
What is done?

DEPRESSION

during labor w/ pitocin
nothing is done

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What is done if a parturient develops ST-T wave elevation

REFER to CARDS because this is a pathologic finding and is NOT normal variant

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Describe the clinical implications of altered PR intervals & uncorrected QT intervals during pregnancy

DEC risk of QT prolongation complications d/t INC HR

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When is the parturient at highest risk for complications r/t long QT syndrome

40 weeks POST-delivery

high risk for VT

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How may parturients with prolong QT syndrome be treated

beta-adrenergic antagonist during & post-delivery

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What is the most common parturient CV abnormality and causes (4)

Tachydysrhythmias

Causes:

change in cardiac ion channel conduction
INC cardiac size
Changes in autonomic tone
Hormones

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What is the treatment for tachydysrhythmias in the parturient

beta-adrenergic antagonist

How does pregnancy affect cardiac output and why

INCREASES - result of INC HR in 1st trimester - d/t INC SV by 2nd trimester

When does CO increase peak in pregnancy and by what %

Around 32 weeks (by end of 2nd trimester) | Peak ~50% of baseline

A parturients pre-pregnancy CO is 5 L/min. What would her CO be by the end of the 2nd trimester

7.5 L/min INC by 50% 5 x 1.5 = 7.5

Pre-pregnancy CO is 5, what is the CO by the end of 1st trimester.

6.75 - 7 l/m

How does pregnancy affect stroke volume by 1st & 2nd trimester

INCREASES 1st=20% 2nd=25 - 30%

The parturients pre-pregnancy SV is 60 - 110 ml. What is the estimated SV by the end of 1st and 2nd trimester?

1st: 72 - 132 ml 2nd: 78 - 154 ml

How can CO alter during the 3rd trimester and why

Can DECREASE | d/t venous compression impeding VR

How does peripheral distribution (blood flow) change during pregnancy and to where

Distribution INCREASES - UBF is INCREASED - INC skin blood flow (3-4x baseline)

How does labor alter CO in between contractions

There is an additional 40% INCREASE by 2nd stage labor

Which increases more, SV or HR, to increase CO during 2nd stage labor

INC SV >> INC HR

How is CO affected by the 1st stage of labor. What factor may affect the CO

Latent phase = INC 10% Active phase = INC 25% INC VR & altered SNS activity can INC CO

How is distribution of BF affected by contractions and why

300 - 500 ml of blood is autotransfused via redistribution from UBF into central circulation d/t INC uterine pressure during contractions

When is the greatest INC in CO during pregnancy and why

Immediately following delivery (3rd stage) D/t autotransfusion of BF from uterus during contractions - INC VR - altered SNS activity - Pressure relief on VC - DEC LE venous pressure - DEC venous capacitance

Describe CO 24 hrs postpartum

24 hrs = Returns to pre-LABOR values 12 - 24 wks = CO return to pre-pregnancy baseline

How does SVR change during pregnancy

DEC of 35% at 20 weeks INC ~20% from baseline when NEAR TERM

**What factors alter SVR during pregnancy (4)**

1. Low resistance placental circulation 2. Progesterone, prostacyclin, estrogen 3. DEC blood viscosity 4. Vasculature loses responsiveness to ANGIOTENSIN

How does the low resistance of placental circulation affect SVR and why

- DEC SVR d/t 1. parallel systemic circulation 2. DEC afterload

How do hormones (progesterone, prostacyclin, estrogen) alter SVR and why

DECREASES | -increased levels cause vasodilation and relax vasculature

Is is blood viscosity altered and how does it affect SVR

DECREASED - INC in plasma vol vs RBC - Causes decreased viscosity d/t dilutional anemia

What 4 factors impact BP during pregnancy

Positioning Gestational age Maternal age Parity

How do positioning and gestational age affect BP during pregnancy

Positioning: SUPINE leads to aorto-caval HoTN Gestational age: SVR INC by end of pregnancy

How do maternal age and parity affect BP during pregnancy

Maternal age: Old parturient can have more comorbidities Parity Higher parity = higher HTN incidence

How is EF altered during pregnancy and why

Alteration: INCREASED Why: INC volume INC HR DEC SVR

How are LVEDV & EF affected by pregnancy

``` LVEDV = INCREASE EF = INCREASE ```

How are CVP, PA diastolic pressure, PCWP altered during pregnancy

All are unchanged or DECREASED

**What CV parameters are increased during pregnancy (5)**

EF, LVEDV, CO, SV, HR

**What CV parameters are unchanged or decreased during pregnancy (4)**

CVP, PA diastolic pressure, PCWP, SVR

**The initial increase in CO is d/t ____**

an INCREASE in HR

**Left axis deviation can be seen on 3rd trimester EKG because **

-Heart shifted ANTERIOR & LEFT

What is aortocaval compression & why does it happen

IVC compression against vertebral column by enlarged uterus when supine Due to: - DEC VR - DEC SV & CO b/c DEC RA filling - DEC uteroplacental perfusion

What does aortocaval compression lead to and when can it be appreciated

Supine Hypotensive syndrome Seen as early as 13 - 16 weeks gestation Biggest problem @36 - 38 weeks

When can aortocaval incidence decrease and why

After 38 weeks | D/t fetal head descent into pelvis

How is aortocaval compression avoided or treated

1Do not lay term gravid pt flat on back | 1Place in left uterine displacement position

**What happens to VR when the pregnant patients lies supine**

``` DEC VR d/t compression DEC RA filling DEC CO/SV DEC uteroplacental perfusion DEC fetal perfusion/HR ```

**Will the BP in the upper extremity INC or DEC when the abdominal aorta is compressed**

INCREASE (similar to cross-clamping)

How is LE BP affected by aortocaval compression

Will DECREASE LE BP

What are symptoms of aortocaval compression (5)

1. Tachycardia (initially) 2. Bradycardia (late) 3. N/V 4. Pallor 5. LOC

Methods to avoid aortocaval compression

- Do not lie flat - Tilt 15* left - Do not sit up (leg flexion rotates uterus & compresses IVC)

**What position would you place the term parturient experiencing tachycardia, n/v, and pallor**

Left uterine displacement position

**How is aortocaval compression fixed**

Left uterine displacement position

**What respiratory anatomic change occurs d/t INC intraabdominal volume**

- Elevated diaphragm displaces lungs cephalad - Widened AP/Transverse diameter - INC diaphragmatic excursion - DEC chest wall excursion

What hormone leads to pulmonary anatomic changes & why

Relaxin - Relaxes ligamentous attachments to lower ribs - Progressively widens subcostal angle

How does the widened AP & transverse diameter of thoracic cage alter chest wall excursion

DECREASES

Is FRC INC or DEC in parturient? | **Why is this important to anesthesia provider?**

DECREASED Importance = little apneic reserve, desat quickly on induction etc?

What factors lead to SOB of the parturient (6)

1. INC respiratory drive 2. DEC PaCO2 3. Large uterus 4. Larger pulmonary BV 5. Anemia 6. Nasal congestion

How is tidal volume altered during pregnancy? | When is majority of change?

Vt + 45% | Majority during 1st trimester

How are the following volumes affected by pregnancy IRV ERV RV

IRV + 5% ERV - 25% RV - 15%

Which volumes are increased and decreased

Increased: Vt, IRV Decreased: ERV, RV

Calculate the pregnancy changes in volume for the following baseline values Vt 500 ml IRV 3100 ml ERV 1200 ml RV 1000 ml

Pregnancy values ``` Vt = 725 ml IRV = 3,255 ml ERV = 900 ml RV = 850 ml ```

How is FRC altered during pregnancy? | When does the decrease begin?

FRC - 20% | Decreases around 5th month

How are the following capacities affected by pregnancy IC VC TLC

IC + 15% VC = unchanged TLC - 5%

Which capacities are increased, decreased, or unchanged.

Increased: IC Decreased: TLC, FRC Unchanged: VC

Calculate the pregnancy changes in capacities for the following baseline values IC 2,050 ml VC 60 - 70 ml/kg TLC 6,000 ml FRC 2,400 ml

IC + 15% = 2,385 ml VC = unchanged TLC - 5% = 5,700 ml FRC - 20% = 1,920 ml