What is the p50O2 in mmHg? Fetal Normal Parturient (mom)

19 27 30 Note: P50 = 50% of Hb is saturated with oxygen.

Pregnancy: Physiologic Changes and Pathophysiology Flashcards by Cindy Ehret

What is the average healthy weight gain during pregnancy?

25 - 35 lbs, or 12 kg

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What causes increase in body weight during pregnancy?(3)

Increased size of uterus (4kg)

Increased blood volume and interstitial fluid (4kg)

Increased fat and protein deposit (4kg)

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How much weight is gained in the 1st, 2nd, and 3rd trimesters?

1st: 1-2 kg

2nd, 3rd: 5-6 kg

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How much is VO2 increased during pregancy and what is the primary cause?

Note: VO2 is oxygen consumption.

~ 60%

Primarily: Needs of fetus, uterus, and placenta
Secondarily: Increased work of mom

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What are anatomical physiological changes during pregancy? (4)

Thoracic cage circumference increases

Vertical measurement of chest decreases

Capillary engorgement of oropharynx, nasal mucosa, larynx

Dilation of large a/w to allow more ventilation

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What can we expect with nasal instrumentation to a pregnant patient?

increased epistaxis

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What are respiratory mechanics in pregnant women? (2)

More diaphragmatic excursion

Less thoracic cage movement

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What are cardiovascular changes in a pregnant woman? (5)

increased blood volume

increased cardiac output

increased HR

increased stroke volume

right shift of oxyhemoglobin dissociation curve

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How much is blood volume increased at full-term?

~1 liter

Note: BV increase mostly due to plasma.

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Most CO output changes is due to stroke volume. True or false?

True

Note how CO increases 125% at birth.

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What are the hemodynamic changes at full-term gestation relating to:

CO
SV
HR
Contractility
SVR
PVR

Cardiac Output +40%

Stroke Volume +30%

Heart Rate +15 (15-20 bpm)

Contractility negligible

SVR - 20%

PVR - 30%

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What is the p₅₀O₂ in mmHg?

Fetal
Normal
Parturient (mom)

Note: P₅₀ = 50% of Hb is saturated with oxygen.

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What are uterine blood flow increases at full-term gestation?

Normal 50 ml/min to 600-700 ml/min

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What are other hemodynamic changes at term gestation besides increased uterine blood flow?

Renal plasma flow increase

Skin blood flow increases 3-4 times

Blood pressure falls

Systolic 6-8%
Diastolic 20-25% early, normal at full-term

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What are factors that impair uterine blood flow? (5)

Decreased perfusion pressure
Decreased uterine arterial pressure
Increased uterine venous pressure
Increased uterine vascular resistance
Exogenous vasoconstrictors

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What is important to know regarding uterine blood flow?

It is pressure dependent and not auto-regulated!

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What factors decrease uterine arterial pressure? (3)

Supine position due to aortocaval compression

Hemorrhage, hypovolemia

Hypotension from drugs or sympathetic blockade

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What factors cause increased uterine venous pressure, which in turn impairs uterine flow? (4)

Vena caval compressions

Uterine contractions

Drug-induced hypertonus (oxytocin, local anesthetics)

Skeletal muscle hypertonus (seizures, Valsava)

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What factors cause increased uterine vascular resistance which in turn impair uterine blood flow?

Endogenous vasoconstrictors

Catecholamines (stress)
Vasopressin (in response to hypovolemia)

Exogenous vasoconstrictors

Epi
Phenyl > ephedrine
Local anesthetics in high conc.

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What is of greater concern, aortic or caval compression?

caval compression

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What position results in complete caval compression?

How much does it decrease CO?

supine, begins at 13 weeks

25-40%

Note: lateral decubitus partially obstructs the vena cava, but collateral circulation can compensate.

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Lateral decubitus causes little aortic compression. True or false?

True.

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At what spinal levels does significant compression of the aorta occur?

L3-L5

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What are the greatest changes in lung volumes at full-term?

Tidal volume increases 40%

FRC decreases 20%

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What changes in respiratory physiology occur at full-term? (3)

Respiratory Rate +0-15% Minute ventilation + 40% Alveolar ventilation + 40%

What is PaCO2 in a non-pregnant vs. a pregnant woman?

Normal: 40mmHg Pregnant (all trimesters): 30mmHg

How does HCO3 change in a non-pregnant vs. pregnant womam?

Normal HCO3: 24 mmHg Pregnant (full-term): 20 mmHg

What happens to pH in a pregnant woman?

Slightly increases

What causes CNS depression in a pregnant woman?

progesterone ## Footnote Note: As a result, less local anesthetics are needed for spinals and epidurals.

Because the CNS is depressed, MAC and amount of local anesthetics needed is decreased as much as \_\_\_-\_\_\_\_%

30 (LA)-40 (MAC)%

What are special considerations for spinals and epidurals in pregnant women? (2)

Engorged venous plexus can increase risk of puncturing epidural vein or intravascular injection Decreased CSF volume causes enhanced cephalad spread of LA

What are renal changes relating to: Blood flow GFR BUN/Cr

BF increases GFR increases BUN/Cr decrease

What are hepatic changes in pregnant women relating to: Blood flow Plasma cholinesterase

Hepatic function and blood flow remain largely unchanged Plasma cholinesterase decreases, but not signicantly for our purposes

What are hepatic related issues that may present to the pregnant woman?

Acute fatty liver Gallstone formation more likely due to concentration of bile

What are changes in colloid (a portion of plasma proteins) osmotic pressures in the pregnant pt?

Decreases by 5mmHg at term

What are coagulation changes that occur with pregnant women relating to: platelet turnover clotting fibrinolysis

all increase

By how much does PT and PTT change during pregnancy?

both decrease by 20% Note: Normal PT is 10-14 sec and PTT is 25-38 sec.

What are changes to the endocrine system with pregnant women relating to the: thyroid parathyroid insulin

Hyper or hypo-thyroidism Increased PTH Insulin-resistance in 3rd trimester

What are GI changes during pregnancy? (7)

Delayed gastric emptying Decreased GI mobility Decreased gastric pH **Decreased gastric acid secretion** Silent regurgitation Increased gastric volume INCREASED ASPIRATION RISK

What are general anesthesia concerns relating to the pregnant pt? (4)

Smaller ETT required Increased shunt when supine Increased rate of denitrogenation Increased rate of decline of PaO2 during apnea

When should you proceed with surgery in the pregnant pt?

If elective, postpone until postpartum. If greater than minimal increased risk to mother, proceed with surgery.

What are the phases in Stage 1 labor? What are the cervical dilations for each?

Latent phase: onset of labor, 2-4 cm Active phase: increased frequency of contractions, up to 10 cm

What is Stage 2 of labor?

Full cervical dilation→Fetal descent→delivery of fetus

What is Stage 3 of labor?

Delivery of the placenta

How much blood is dispaced from the uterus to the central circulation with each contraction?

300-500ml

What drug is given to induce labor?

Pitocin (Oxytocin)

What drugs are given after delivery to contract the uterus back down to prevent hemorrhage?

Methergine Hemabate

What drug is given for pre-eclampsia?

Magnesium

What are pregnancy induced diseases? (6)

* Pre-eclampsia (pregnancy-induced HTN) * Eclampsia (severe preg-induced HTN) * Acute fatty liver * Amniotic fluid embolism * Thromboembolic disease * DVT/pulmonary embolus

What is preeclampsia?

BP \> 140/90, or \>20% above baseline Proteinuria and/or Edema Usually presents 20 weeks after gestation

What is HELLP syndrome?

**_H_**emolysis **_E_**levated **_L_**iver Enzymes **_L_**ow **_P_**latelets Note: Only 2 of 3 conditions are needed.

What is eclampsia?

Preeclampsia with seizures

Preeclampsia and HELLP syndrome is an _______ situation.

emergent

What is the treatment for preeclampsia?

Generally resolves after delivery, but others may require ICU if pulmonary/renal issues.

What are the symptoms of eclampsia? (5)

profound HTN headache double vision hyperreflexia convulsions

What is the differential diagnosis for eclampsia?

Amniotic fluid embolism which leads to hypoxia and seizures IV injection of LA but no HTN will be present in this instance

What are anesthetic considerations for pts with eclampsia?

Secure the a/w in event of seizure! Smaller tube RSI

What are neurological complications of PIH (pregnancy-induced HTN)? (5)

Headache Visual disturbances Hyperexcitability Seizures Intracranial hemorrhage

What are cardiovascular complications of PIH? (3)

decreased intravascular volume increased arteriolar resistance heart failure

What are hepatic complications of PIH? (3)

elevated liver enzymes hematoma hepatic rupture

What are renal complications of PIH? (4)

Proteinuria Na retention Decreased GFR Renal failure

What are hematologic complications of PIH? (2)

Coagulopathy Microangiopathic hemolysis

Acute Fatty Liver is common/rare.

Rare, 1/12,000 of deliveries but deadly.

What are the symptoms of acute fatty liver?

N/V Epigastric pain Jaundice Decreased serum glucose Increased liver enzymes Note: Presents in 3rd trimester.

What is the treatment of acute fatty liver? (3)

Supportive FFP, platelets, albumin Give vitamin K Note: Hope that pts do not go into DIC (excessive thrombin).

When is the onset of amniotic fluid embolism? What are the symptoms? (6)

During delivery Sudden CV collapse Profound hypotension Cyanosis Seizures, Coma DIC Presents as anaphylaxis Note: Rare, but deadly.

What is the treatment of amniotic fluid embolism?

Deliver the baby Provide supportive care

What is DIC (disseminated intravascular coagulation)?

Widespread systemic activation of coagulation, resulting in intravascular formation of fibrin and ultimately thrombotic formation occlusion of small and mid-sized vessels.

What are the causes of DIC?

Sepsis Trauma Obstretics Note: Treatment is supportive and treat underlying cause.

What is thromoembolic disease?

Pregnancy causes an increase in most clotting factors. Gravid uterus causes venous stasis.

What are risk factors for thromboembolic disease? (4)

Smoking Obesity Age Genetics

How do we diagnose DVTs? What can they ultimately cause? What is the treatment?

Doppler Pulmonary embolus Massage, heparin therapy Note: Heparin is OK for the baby.

What are anesthetic considerations for respiratory patients with asthma and cystic fibrosis, for example?

Do not go above T8 with the epidural due to effects on breathing!

Is synthroid OK for the pregnant woman?

Yes

Is glucophage OK for the pregnant woman?

Yes, oral hypoglycemics are fine.

What are anesthetic considerations for pregnant women with renal disease?

Increased risk for HTN Decreased fluid clearance

What are anesthetic considerations for epileptic pregnant patients?

More seizures Decrease meds due to increased risk of cleft lip/palate

What are anesthetic considerations for myasthenia gravis pregnant pts?

Some pts get better, worse, or stay about the same Stress can exacerbate MG Resistance to anticholinesterases?

What are the anesthetic considerations for pregnant women that are morbidly obese?

GI issues A/w issues Diabetes

Pregnancy: Physiologic Changes and Pathophysiology Flashcards

(79 cards)