OB (4/10) Flashcards
oxygen uptake in fetus is ________x that of the adult, but decreases significantly with hypoxemia
2
fetal circulation directs oxygenated blood to the _______________ & ___________ and deoxygenated blood to the ____________ & ________
Brain; heart; umbilical circulation; placenta
describe the flow of fetal circulation starting at the placenta
(oxygenated) placenta –> liver –> portal sinus and ductus sinus –> IVC –> right atrium –> foramen ovale –> L. atrium –> L ventricle –> aorta –> brain and myocardium (ensuring they get the highest concentration of O2 blood)
(deoxygenated blood) coming in from lower extremities and SVC –> R. ventricle –> pulmonary trunk –> ductus arteriosus –> descending Ao –> lower extremities and hypogastric arteries –> returns to placenta via umbilical arteries
the fetal oxyhgb dissociation curve is shifted to the ______________ with respect to the adult (non-pregnant) form and the pregnant womans oxyhgb curve lies to the ____________ of the nonpregnant
left; right
what would you expect to happen to the pregnant mothers oxy-hgb dissociation curve with hyperventilation
move left
why does fetal blood have higher affinity for O2 than the mothers
fetal hgb has no B-chain so has higher affinity
what are the 3 major shunts of fetal circulation
- ductus venosus
- foramen ovale
- ductus arteriosus
the fetal circulatory shunt bypasses the liver via the ________________
ductus venosus
_________________ is the shunt in fetal circulation which bypasses pulmonary circulation
ductus arteriosus
what is the purpose of oxytocin (“pitocin”)
- induce or augment labor
- induce uterine contractions
- maintains uterine tone
- given postpartum to increase uterine tone and stop bleeding
dose of oxytocin when used to augment/induce labor
3-40 miliunits/min titrated to achieve normal contraction pattern
dose of oxytocin postpartum to decrease hemorrhage
10-40 units per IVF bag or 10 units IM
common s/e of pitocin
- uterine hypertonicity
- N/V
_______________ are what change the size of the cervix
contractions
what is the black box warning for oxytocin
not indicated for elective labor
(but this is what we primarily use it for…)
serious side effects of pitocin
- anaphylaxis
- SIADH
- HTN
- arrhythmias
- postpartum hemorrhage
- pelvic hematoma
- vaginal or cervical laceration
- abruption
- uterine rupture
- uterine tetany
what is the laboring dose of oxytocin
0.5-1 mU/min
what dose of pitocin is equivalent to spontaneous labor
6 mU/min
what are the different drugs used for uterine atony
- oxytocin
- methylergonovine (methergine)
- hemabate
- misoprostol (cytotec)
if you have given pitocin for uterine atony after delivery, but the uterus is still boggy what drug should you give
methergine
dose of methergine
0.2 mg IM
can be repeated x1 after 1 hour
contraindications to using methergine for uterine atony
- htn
- preeclampsia
- CAD
________________ is a drug used for uterine atony, has a long duration of action and may be repeated 1x after 1 hour
methergine
if pt has htn you would not give methergine you would instead give hemabate
s/e of methergine
- thromboembolic sequelae
- severe N/V
- arteriolar constriction
dose of hemabate
250 mcg IM or IU for uterine atony
can be repeated q15min up to 2 mg
c/i to using hemabate
- reactive airway dz
- pulmonary htn
- hypoxic pts
s/e of hemabate
- bronchoconstriction
- shivering
- Temp increase
- diarrhea
dose of misoprostol (cytotec) for uterine atony
800-1000 mcg PR
s/e of misoprostol (cytotec)
- shivering
- temp increase
- N/V/D
what is the rule of 3’s to guide pitocin administration
- 3 units of pitocin given IVP
- assesment of uterine tone at 3 minute intervals, redosing if needed with 3 unit boluses up to a total of 3
what are the different ways to administer pitocin
- 200 mU/min for several minutes until uterus remains fimr then 1-2 mL/min until discharge
- 20 units in 1 L LR wide open then add 20 U to next IV bag
- 30 units in 500 mL of LR wide open
- 10 units IVP then 20 units in > 500 mL, add 20 more units per surgeon request
- 30 u/500 mL on pump at 333 mL/hr x 1 hour then 42 mL/hr after that til bag is complete
what is the third line drug for uterine atony?
hemabate
_____________ is a synthetic prostaglandin that stimulates uterine contraction
hemabate
what is the common on label use of misoprostol (cytotec)
cervical ripening
cytotec is administered via what route for cervical ripening? what route for post partum uterine atony?
- ripening = oral or vaginally
- postpartum atony = rectal
_______________ is a synthetic analogue of lysine
TXA
MOA of TXA
prevents fibrin degradation
use of TXA
- postpartum bleeding
- trauma
- surgery
- tooth removal
- nose bleeds
- being used in prophylaxis for high risk pregnant moms before C-section
dose of TXA
1000 mg IV over 30 minutes, can be repeated once
T/F: if mom has covid 19, you should avoid TXA
true - increased risk of clot
use of cervidil
cervical ripening
dose/administration of cervidil
10 mg via vaginal suppository - leave in x12 hours
under what circumstance would you remove the vaginal suppository cervidil from the pt before 12 hours
- if pt cervix dilates > 4 cm
- rupture of membrane
- non reassuring fetal heart tones.
after placing cervidil, what positioning instructions should you give the pt
must lie flat for 2 hours
what are the s/e of cervidil
cramping
_______________ is a stick poked in the cervix for cervical ripening, mother is sent home and then next morning comes to the hospital for induction of labor
dilapan-S
______________ initates endogenous prostaglandin release causing collagen degradation –> cervical softening
dilapan-S
______________ is a catheter with 2 large ballons inserted into cervix, every few hours nurse tugs on catheter, once comes out pt is dilated to _________ cm
cook catheter; 4-5 cm
______________ is a beta adrenergic agonist that is used a tocolytic
terbutaline
dose of terbutaline for tocolysis
0.25 mg SQ
