FINAL Flashcards
When does aortocaval compression become significant in pregnancy?
18-20 weeks
-if uterus is larger than normal (multiple gestations/polyhydramnios) aortocaval compression may appear earlier
What are the signs and symptoms of supine hypotension syndrome?
-Hypotension
-Sweating
-Bradycardia
-Pallor
-Nausea
-Vomiting
What is the best vasoactive for treating hypotension in the parturient?
Phenylephrine
What is ion trapping, and how does fetal pH affect transfer of medications across the placenta?
Fetal pH is lower than maternal pH, so that weak bases become more ionized in the fetus, thus limiting their transfer back across the placenta. Normally, the difference in pH is only 0.1 and this “ion trapping” is irrelevant, but fetal acidosis can significantly increase the fetal concentration of drugs such as local anesthetics.
Significant maternal stress or lack of BF can cause fetal acidosis. Basic drugs are more likely to get trapped. Fetal acidosis can increase the concentration gradient which leads to ion trapping
Which medications do not cross the placenta?
NMBs
Heparin
Insulin
Glycopyrrolate*** answer to red book question
Which medications do cross the placenta?
Local anesthesthetics (except chloroprocaine d/t rapid metabolism)
IV anesthetics
Volatile anesthetics
Opioids
Benzodiazepines
Atropine
Beta-blockers
Magnesium
What are the symptoms of magnesium toxicity?
HYPOmagnesium 1mg/dL= seizures
HYPERmagnesium
-8-10mg/dl= decreased deep tendon reflexes
-10-15mg/dL= Widened QRS and PR interval (cardiac conduction defects), respiratory depression
-20+ = cardiac arrest
Treat with calcium gluconate or CaCl
Prostaglandin F2: Carboprost (Hemabate) indications, contraindications, and dosage:
3rd line uterotonic
Dose: 250mcg IM or injected into the uterus
(0.25mg IM) - can be given intrauterine
DO NOT GIVE TO ASTHMATIC PTS= BRONCHOSPASM
Side effects:
-N/V
-diarrhea
-hypotension
-hypertension
-bronchospasm
Methergine indications, contraindications and dosage:
Methergine: Second-line uterotonic
-Dose : 0.2mg IM
DO NOT GIVE IV= HTN/VASOCONSTRICTION
-IV administration can cause significant vasoconstriction, hypertension, and cerebral hemorrhage
-Hepatic metabolism half-life: 2 hrs.
Normal uterine blood flow:
700-900 mL /min at term
Uterine blood flow does NOT autoregulate – therefore, it’s dependent on MAP, CO, and uterine vascular resistance. It’s a low-resistance system, uterine blood flow is primarily dependent on MAP and CO
UBF = UAP-UVP/UVR
(uterine blood flow = Uterine arterial pressure- uterine vascular pressure/uterine vascular resistance)
What CV changes are increased in pregnancy?
Increased HR (15%)
Increased SV
Increased PaO2
Increased CO (highest just after delivery, returns to normal after 14 days)
Increased P50 (right shift, facilitated O2 delivery to fetus)
What CV parameters don’t change in pregnancy?
SBP-No change
MAP- No change
CVP- no change
PAOP- no change
What CV parameters decrease in pregnancy?
Decreased DBP
Decreased SVR
Decrease PVR (decreased response to angiotensin and NE)
Decreased PaCO2 (28-32)
Decreased HCO3
What axis deviation will you see in pregnancy?
Left axis deviation
What medications should not be used in reproductive technology?
Some lab studies suggest suggested that local anesthetic agents, nitrous oxide, and the volatile halogenated agents interfere with some aspects of reproductive physiology in vitro. However, avoid multimodal anesthesia, keep it clean, utilize sedation and perhaps avoid neuraxial analgesia.
Which of the following drugs should NOT be used during transvaginal oocyte retrieval (TVOR) for assisted reproductive technology (ART)?
A. Propofol
B. Ketamine
C. Midazolam
D. All are safe and can be used
D. All are safe and can be used
What are the symptoms of aspiration?
Bronchospasm, high airway pressures, hypoxemia, wheezing, HoTN and tachycardia
Other: sudden coughing, dyspnea/tachypnea, chest wall retraction, cyanosis not relieved by oxygen supplementation, in the development of pink frothy exudate
Tx: supplemental oxygen w/ positive pressure ventilation, peep, or continuous positive airway pressure and suctioning
Risk of aspiration greatly increases after 1st trimester
A 24-year-old gravida 2, para 1 parturient is anesthe- tized for emergency cesarean section. On emergence from general anesthesia, the endotracheal tube is removed and the patient becomes cyanotic. Oxygen is administered by positive-pressure bag and mask ven- tilation. High airway pressures are necessary to venti- late the patient, and wheezing is noted over both lung fields. The patient’s blood pressure falls from 120/80 to 60/30 mm Hg, and heart rate increases from 105 to 180 beats/min. The MOST likely cause of these manifestations is
A. Amniotic fluid embolism
B. Mucous plug in trachea
C. Pneumothorax
D. Aspiration
D. Aspiration
What are the consequences of general anesthesia on the fetus?
Neonatal respiratory & CNS depression
Non-obstetric surgery during pregnancy:
growth restriction
low birth weight
demise
↑incidence of preterm labor (highest during intraabdominal + pelvic surgery)
c. No anesthetic agent is a proven teratogen in humans.
d.Nitrous oxide has been shown to have teratogenic effect in rats during 1st trimester. Typically avoided during first 2 trimesters
When is the fetus most susceptible to the effects of teratogenic agents?
A. 1 to 2 weeks of gestation
B. 3 to 8 weeks of gestation
C. 9 to 14 weeks of gestation
D. 15 to 20 weeks of gestation
B. 3 to 8 weeks of gestation
What is placenta previa?
Typically presents as painless vaginal bleeding.
Considered complete previa when cervical os is entirely covered by placenta or can be some variation of partial cover
What places pts at risk for placenta accreta?
Pts with a previous history of c-section
Current placenta previa
What kind of previa is this?
COMPLETE
What kind of previa is this?
Partial
What kind of previa is this?
Marginal
What kind of previa is this?
Low-lying