ITE OB 2 Flashcards
Bupivacaine has (high/low) placental transfer
low
- bc it is highly protein bound
Determinants of local anesthetic placental transfer (2)
- degree of ionization at physiological pH
2. amt of protein binding
Protein bound drugs are (readily/unable) to cross the uteroplacental barrier
unable to cross
the ___ is the pH at which a drug has equal [ ] of ionized (protonated) and nonionized (nonprotonated) forms
pKa
drugs can freely pass the placenta in the (ionized/nonionized) state
nonionized
____ fetal drug accumulation d/t pH differences btwn maternal and fetal blood, esp in fetal acidosis
ion trapping
Bupivacaine has a pKa of ___, so at physiological pH of ___ (lower than the drugs pKa), there is more drug in the (ionized/unionized) state
8.1, 7.4
ionized form
- unable to cross placenta
Most amide local anesthetics are (highly/poorly) lipid soluble
highly
Why is lidocaine and 2-chloroprocaine not used for maintenance of epidural anesthesia?
tachyphylaxis
- rapidly diminishing response to successive doses, making it less effective
*use bupi and ropi instead
Preeclampsia is associated with (increase/decrease) thromboxane A2 levels and (increase/decrease) prostacyclin levels
increase
- hypercoagulability
decrease
- vasoconstricted state
Preeclampsia is characterized by global vascular hyperreactivity leading to ___ (4)
- intravascular volume depletion
- high systemic vascular resistance
- uterine vasoconstriction
- decreased uterine and placental blood flow
amniotic fluid embolism leads to pulmonary (vasoconstriction/vasodilation) and generally causes ____ shock
intense pulmonary vasoconstriction
cardiogenic from RHF
Two stages of amniotic fluid embolism
- pulmonary vasospasm and RHF
2. pulmonary edema and LHF
a healthy fetus has a relatively (high/low) pH when compared to its mother
low (7.35) vs 7.43
a (acidic/basic) drug (ie. local anesthetic) that crosses the placenta in the unionized form accepts a H+ and becomes ionized and trapped
basic
- ie: lidocaine as pKa of 7.8 and more will exist in its ionized (charged, non-lipophilic) fraction as pH decreases below 7.8
Drugs that do not cross the placenta
He Is Going Nowhere Soon
- Heparin
- Insulin
- Glycopyrrolate
- Nondepolarizing muscle relaxants
- Succinylcholine
(Glycopyrrolate/Neostigmine) does not cross the placenta
Glycopyrrolate
- neostigmine will and fetus can become bradycardic
- use atropine instead
Loss of fetal heart rate variability is an early sign of _____
fetal hypoxia
Head compression can ppt _______, which require which type of intervention?
early decels
none
what FHT is a response to hypoxemia?
late decels
- lag 10-30 sec behind uterin contractions
DIC is associated with elevated ____ with decreased _____ and ____
PTT
platelets, fibrinogen
*other factors like fibrin, fibrinogen are already elevated in pregnancy
Most common causes of DIC
preeclampsia placental abruption sepsis postpartum hemorrhage Amniotic fluid embolism