OB- Clow Flashcards
What 2 things need to be considered starting at 20 weeks?* 14 weeks (2nd trimester)
- LUD
- RSI
Rob said for both - LUD & RSI start in the second trimester. 14 weeks
LUD anywhere between 14-26 weeks
(MAC decreases ~ 8-12 weeks)
Mom vs baby on oxyghemoglobin curve
Normal P50
mom = shifted right (right = release to baby) [30]
baby = left (left=love) [10]
27
CO2 goals for pregnant patient
normocarbic 35-45
hyperventilating reduces maternal CO and uterine blood flow and can compromise fetus
how does dead space change in mom?
increases 40%
T/F- TV/dead space ratio increases with pregnancy
false its unchanged - both increase 40%
How many cc’s of LA does it take to get to a T4 level on a pregnant patient for an epidural
what if they aren’t pregnant?
pregnant = 20cc
non-pregnant = 30cc
T/F- estrogen is the main stimulatory hormone in pregnancy
true - increases CO, NV, and angiotensin
what hormone is responsible for 3rd spacing?
aldosterone - increases total body water
path of blood flow from mom to baby
which deliver oxygenated blood vs return deoxygenated blood?
mom > uterine arteries > placenta > 1 umbicial vein (oxygenated) > baby > 2 umblical arteries (deoxygenated) > placenta > uterine veins > mom
uterine blood flow is inversely proportional to what?
what would cause this
uterine vascular resistance (increase resistance, decreased blood flow)
catecholamines (alpha stimulation: epi, neo, ephedrine)
why should you try and give IV meds to mom during contractions?
bc uterine contraction → decreased UBF → less to baby → more to mom
about how much blood gets autotransfused to mom during a contraction
500mls
T/F- acceleration of fetal HR in response to stimualtion is a good sign
TRUE
Pregnancy drug category:
in controlled human studeis, drug does not demonstrate risk to fetus in any trimester
3 examples
A - safe
folic acid, levothyroxine, doxylamine (unisom, but can actually treat pregnancy induced NV)
Pregnancy drug category
Use of drug in pregnant women demonstrates risk to human fetus, but potential benefit to mother may outweigh risk to fetus
4 examples
Category D - ONLY used in serious/lifethreating condidtion when alternatives are unavailable
+evidence of fetal risk, but benefits may outweigh risks
Lisinopril, Losartan, Lithium, Phenytoin
Pregnancy drug category
In animal studies, drug is associated with adverse effect and there are no controlled human studies
or
there are no animal or human studies
3 examples
Category C
only use if potential benefit outweighs potential risk
fluconazole, metoprolol, sertraline
*sertraline = zoloft = SSRI (enzyme inhibition)
*fluconazole = azole antifungal (enzyme inhibition)
what pregnancy drug catagory would it be if there are no animal or human studies for the drug
Category C
or animal studies +adverse effect but no human studies
What pregnancy drug category details a drug that is contraindicated in women who are pregnant or may become pregnant
X
methotrexate (chemo), simvastatin, warfarin
Pregnancy drug category
In animal studies, drug does NOT demonstrate risk to fetus and there are no controlled human studies
or
in animal studies, drug is associated with adverse effect but in controlled human studies, drug does not demonstrate risk to fetus in any trimester
3 examples
B “should be ok”
zofran, amoxicillin, loratadine
Radation is safe up to what?
50mGy
Whats the test dose for epidurals
45mg lido (3cc of 1.5% (15mg x 3)
+/- 15mcg epi (3cc of 1:200,000 [5mcg x 3 = 15mcg]
What’s the first thing you should do if your called to treat breakthrough pain for a laboring mom with an epidural
check the catheter site to see if it migrated before bolus’ing/increasing rate
If need to convert to surgical anesthesia and someone asks you to pull up”fast lido” what’s that ?
20mls lido/2mls bicarb
some might ad a swirl of epi and/or opioids
Spinal level for PPTL
T5-T6
2 characteristics of tetracaine that make it not a great option in OB
slow onset and stonger motor block
Why does bicarb speed the onset?
it makes the drug less ionized at phisologic pH , therefore speeding the onset
mneumonic for amides that cross the placenta from highest to lowest
MELRUB
Mepivacaine
Etidocaine
Lidocaine
Ropivacaine
Bupivacaine (most protein bound)
which local anesthetic crosses the placenta the least of any?
chloroprocaine (metabolized in blood by esters before it can get to baby)
Say you have a T10 level and need to get to a T4- how much LA should you inject into the epidural?
1-2cc/ level
6 levels x 1.5cc = 9ccs
when is mom most likely to have symptoms of a PDPH?
usually 2nd day PP
If mom cardiac arrests, the fetus should be delivered within how many minutes of arrest
2 adjustments u need to make compared to non-pregnant
5 mins
LUD and compressions with hands slightly above center of sternum
(CPR will be more effective once baby is out due to less aortocaval compression → better blood return/volume)
What 2 structures does the epidural space lay between?
ligamentum flavum → epidural space → dura matter
→ subdural space → arachnoid membrane → subarachnoid space → pia matter → spinal cord
What 2 structures does the subarachnoid space lay between?
arachnoid membrane → SA space → pia matter
→spinal cord
why should you wait to continue doing spinal if mom starts a contraction?
bc contraction will elevate the spina llevel
50%nitrous increases your MAC by how much?
2x (50%nitrous doubles your MAC)
Crash section- baby should be out in what time frame
3 minutes or less
If you cant intubate and have to result to an LMA (proseal) to secure airway - what do you need to consider?
they will have to avoid fundal pressure (increased risk of aspiration)
If pt can’t dorsiflex their foot (footdrop) after vaginal hysterectomy, what nerve is injured
what is compressed in what position?
Common peroneal
head of the fibula is compressed by the strap in lithtomy position
what nerve injury if after vag hyster, lateral thigh has decreased sensation?
lateral fem cutaneous
How does pitocin work?
what is the mechanism that causes hypotension?
increases permeability to calcium ions, increasing the number of contracting fibrils and increases uterine tone post delivery (increases contraction strength and frequency if used for induction)
well pitocin increases the conductance of calcium and calcium can stimulate the nitric oxide pathway and result in vascualr relaxation- BAM
What should you never give pitcoin with?
D5W - never give with water (water intoxication)
how does methergin work?
who should it be avoided in?
it increases uterine tone by direct alpha adrenergic stimulation
HTN, pre-eclamptic, pulm htn
*light sensitive
dose of methergine
0.2mg IM
comes in 0.2mg/mL vial - give whole CC - IM!!!
methergine
onset:
duration:
1/2 life:
can it be repeated? when?
onset 2-4 mins
duration 2-4 hours
1/2 life 2 hours
can be repeated in 2-4 hours
Dosing of hemabate (Carboprost)
can you repeat?
who should you avoid it in?
0.25mg (250mcg) IM
repeat q 15-30 mins - max of 2mg (8 doses total)
asthmatics (bronchospasm)
How does mag sulfate relax the uterus?
it competes with calcium for entry into the SR → less calcium = uncoupling of the acin-myosin unit → muscle relaxation
*hyperpolarizes the neurons and reduces seizure risk for preeclamptic patients
antidote for mag toxicity
calcium gluconate
mnumonic for treatin amniotic fluid embolism
AOK for AFE
Atropine 1mg (tx vagal response)
Odansetron 8mg (suppress serotonin effects [vagal] from platelet degrandulation)
Ketorolac 30mg (inhibit thromboxane A2 which is ultimately causing pulm vasoconstriction)
platelets degranulate and rlease serotonin (vagal) and thromboxane A2 (pulm vasoconstriction)
What’s etopic pregnancy?
when the fetus implants outside of the uterus (in a fallopian tube)
risk of doing non-ob surgery in the 1st trimester
misscarriage 30-50%
What is puerperium
the time period after placental delivery to 6 weeks post partum
2 most common causes of OB mortality (non-anesthesia related)
PE & PrEeclampsia (24%/20%)
