OB Anesthesia Flashcards
What are the causes of early changes in the pregnant woman?
Effects of progesterone, estrogen and prostaglandins
Increased metabolism demands of the fetus, placenta and uterus
What is the major cause of changes later in pregnancy?
Caused my mechanical displacement by the uterus
What cardiovascular changes are seen during pregnancy/
CO increases by 40%
HR increases
Blood flow increases to major organs
What organs does blood flow increase during pregnancy?
Uterus
Kidneys
Breast
Skin
What do ninety percent of pregnant develop?
Systolic ejection murmur, not pathologic unless greater than class III
What causes CO to increase during pregnancy?
Increase in chamber volume and increase in size of the ventricular wall
Why is there an increased risk of intravascular injection with regional anesthesia in pregnant women?
The extradural veins are distended
How do local anesthetic requirements change during pregnancy?
Decrease LA by 30%
Why does the both the SBP and DBP decrease slightly in the second trimester?
Due to decrease SVR, will return to baseline in third trimester
Why might EKG changes be seen during pregnancy?
The size of the heart increase by 12% and the heart is displaced up to the left and rotates laterally
What type of EKG changes may been seen with pregnancy?
Left axis deviation and ST & T wave changes in lead III
How is blood volume affected with pregnancy?
40-50% increase in plasma volume with an increased volume of distribution
Why might a pregnant patients labs show a low HH?
Hemodilution from a smaller change in blood components than plasma volume
How is clotting affected during pregnancy?
Fibrinogen and Factors VII, IX and X increase markedly
Increased in platelet count
After the second trimester, what can cause a decrease in CO?
Aortocaval compression, when the uterus compresses the aorta and IVC
What position is known to cause aortocaval compression?
The supine position
What can prolonged aortocaval compression cause?
Supine hypotension syndrome
How does supine hypotension syndrome affect the fetus?
Decreased uterine blood flow can result in fetal acidosis during labor
What are symptoms of supine hypotension syndrome?
N/V
Diaphoresis
Possible changes in cerebration
Fetal bradycardia
If a pregnant patient reports nausea while in the supine position what should be assumed?
HoTN and the provider should treat immediately
How should supine hypotension syndrome be treated?
Left uterine displacement:
Wedge under right hip
Tilting OR tabel 15-30 degrees to the left
Using a mechanical uterine displacing device
What is the thought to cause a decrease in airway resistance in the pregnant patient?
Progesterone mediated relaxation of bronchial musculature
Why do pregnant women often complain about having a stuffy nose?
Vascular engorgement of the nasopharynx, larynx, trachea and bronchi
Vocal cord changes and difficulty breathing through the nose
What is the compensatory mechanism for the diaphragm being displaced?
Increased in transverse and AP chest diameters and rib flaring due to hormonal ligament loosening effects