Obstetrics Flashcards
Why do most parturients have mild respiratory alkalosis?
Progesterone increases Mv up to 50%
Airway edema in OB patients is made worse by:
Pre-Eclampsia
Tocolytics
Reverse T (duh)
FRC is reduced in pregnant women as a function of:
Decreased expiratory reserve
Decreased residual volume
How is closing volume impacted by pregnancy?
Increases above FRC, causing airway closure during tidal breathing
How does an ABG differ in a pregnant woman?
PaO2 increases
PaCO2 decreases
Bicarb decreases
In pregnancy the oxyhemoglobin dissociation curve shifts to the:
Right
How is closing capacity impacted by pregnancy?
Remains unchanged, because although the closing volume increases, the residual volume decreases
Respiratory rate increases by:
10%
Minute ventilation increases by:
50%
Why does minute ventilation increase?
Mostly because tidal volume increases by 40%
The increase in rate is small (10%)
All of the lung volume decrease except:
closing capacity and vital capacity
Oxygen consumption is increased by _____% in a term pregnant woman
20%
Oxygen consumption is increased by _____% in the first stage of labor
40%
Oxygen consumption is increased by _____% in the second stage of labor
75%
What hormones contribute to vascular engorgement and hyperemia?
Progesterone
Estrogen
Relaxin
In the 1st stage of labor, CO increases by ___%
20%
In the 2nd stage of labor, CO increases by ___%
50%
In the 3rd stage of labor, CO increases by ____%
80%
Which hemodynamic parameters are unchanged during pregnancy?
MAP and SBP
Which hemodynamic parameters are altered during pregnancy?
DBP, SVR, and PVR DECREASE
How long does it take for CO to return to PRE-LABOR values postpartum?
24-48 hours
How long does it take for CO to return to PRE-PREGNANCY values postpartum?
2 weeks
The cardiac axis on a maternal ECG may show what abnormality?
A L axis deviation, because the gravid uterus pushes it up and to the L
Why are parturients so prone to consumptive coagulopathies?
The have increased clotting factors (hence the hypercoagulable state)
BUT
They also have more fibrin breakdown, meaning they clot easier AND break down clots faster
Coag in pregnant women will show:
Decreased PT (20%) and decreased PTT (20%)
Normal-ish platelets
Pregnant women are more sensitive to which drugs?
Local Anesthetics
Volatile Anesthetics
(because of increased progesterone)
How is gastric emptying impacted by pregnancy?
It isn’t, but it does decrease after onset of labor
Uterine blood flow accounts for ____% of cardiac output
10
What is a normal uterine bloodflow at term?
700-900 ml/min
Which drug characteristics favor placental transfer?
LMW (<500 daltons)
High lipid solubility
Non-Ionized
Non-Polar
Which drugs do NOT cross the placenta?
Paralytics, Glyco, Heparin, Insulin
Which LA reduces the efficacy of epidural morphine?
2-Chloroprocaine
Which opioid has LA properties?
Demerol
Why isn’t lidocaine preferred for epidurals?
It produces a strong motor block, and can cause neurotoxicity if inadvertently injected intrathecally
What is the dose range for spinal bupivacaine?
1.5 - 2.5 MILLIGRAMS
What is the dose range for spinal ropivicaine?
2 - 3.5 MILLIGRAMS
There are three ways to develop a total spinal:
- Epidural dose injected intrathecally
- Epidural dose injected subdural (delayed s/s)
- Spinal injection after failed epidural
How can you prevent a subdural injection?
You really can’t. Neither aspiration or a test dose will rule it out
What is the classic presentation of a subdural injection?
Symptoms of excessive cephalad spread 10-25 min after epidural placement
Why do subdural injections cause total spinals?
Because the potential space is so much small, so the LA rapidly travels up and down
What is the treatment for mag toxicity?
Diuretics
1g Calcium
What are the side effects of pitocin?
Water intoxication
Hypotension
Reflex Tachycardia
Coronary Vasoconstrict.
What is the half life of pitocin?
4-17 min
What are the side effects of methergine?
Vasoconstriction
Hypertension
Cerebral Hemorrhage
What is the half life of methergine?
2 hours
What is the dose of Methergine?
0.2mg
What is the dose of hemabate?
0.25 mg
What are the side effects of Hemabate?
N/V
Diarrhea
Hypotension
HTN
Bronchospasm
How much higher is the mortality from general anesthesia in pregnancy?
17x higher than the general population
During a general anesthetic, the risk of neonatal acidosis increases when the time from incision to delivery exceeds:
3 min
Triple prophylaxis against aspiration includes:
Bicitra
Reglan
Ranitidine
Should a defasciculating dose be given in pregnancy?
Surprisingly no. Myalgia is reduced in pregnancy
What is normal amniotic fluid volume?
700ml
When should NSAIDs be avoided in pregnancy?
After the first trimester
Which surgeries have the highest incidence of preterm labor?
Intraabdominal and Pelvic
What is the best time for a pregnant patient to have surgery?
The second trimester
At what gestational age are women considered a full stomach?
18-20 weeks
Chronic cocaine use is associated with which blood dyscrasia?
Thrombocytopenia
Which obstetric pathologies are associated with DIC?
AFE
Placental Abruption
Intrauterine Demise
What is the neonatal IV dose of epinephrine?
10-30mcg/kg
What is the neonatal intratracheal dose of epinephrine?
0.05 - 0.1 MG/kg
What is the bolus dose of IVF for a neonate?
10 ml/kg
Includes PRBCs
Which local anesthetic DOES NOT cross the placenta
2-Chloroprocaine because it’s metabolized so quickly
Immediately after delivery, neonatal SpO2 should be:
> 60%
After ten minutes, neonatal SpO2 should be:
90%
