OB Flashcards
Which of the following values on an arterial blood gas measurement is MOST LIKELY INCREASED in a healthy pregnant patient compared with a healthy nonpregnant patient?
Increased minute ventilation occurs as early as the first trimester of pregnancy and leads to a respiratory alkalosis with a compensatory metabolic acidosis. On arterial blood gas analysis, this is represented by a normal to slightly increased pH, decreased PaCO2, decreased serum bicarbonate level and decreased base excess. Increased alveolar ventilation also leads to an increase in PaO2.
Which of the following sets of data BEST represents an umbilical arterial blood gas analysis from a normal, healthy fetus immediately following delivery?
Data presented as: pH / PaCO2 (mm Hg) / PaO2 (mm Hg) / Bicarbonate (mEq/L) / Base excess (mEq/L)
The normal average values of an umbilical artery blood gas sample are approximately: pH 7.2-7.3, PaCO2 50-55 mm Hg, PaO2 18-25 mm Hg, bicarbonate 22-25 mEq/L, base excess -2.7 to -4.7 mEq/L.
A woman who is 37 weeks pregnant comes to the operating room for an emergency cesarean section after a motor vehicle crash and significant blood loss. Fetal heart rate monitoring shows persistent fetal bradycardia. Compared with a nondistressed fetus, the risk of fetal toxicity from which of the following drugs is INCREASED in this scenario?
Drug characteristics that facilitate placental transfer include small size (<500 Da), nonionized/lipid soluble, poorly protein bound, and high maternal concentration. Drugs that undergo ion trapping (most importantly local anesthetics) can accumulate more quickly in the setting of fetal acidosis.
TrueLearn Insight : The inability of glycopyrrolate to cross the placenta is important to consider when reversing neuromuscular blockade in a pregnant woman. Neostigmine also has a quaternary structure but does cross the placenta to a small degree. If glycopyrrolate is administrated with neostigmine, the fetus will accordingly be exposed to more neostigmine than glycopyrrolate and can become bradycardic. For this reason, atropine may be preferred in combination with neostigmine to antagonize nondepolarizing neuromuscular blockade in pregnant patients.
Which of the following is the MOST common sign of uterine rupture during labor?
Uterine rupture typically presents with vaginal bleeding, maternal tachycardia plus hypotension, cessation of labor, abdominal pain, and non-reassuring FHR patterns. The latter is the most reliable sign for diagnosis. Common risk factors include prior cesarean section, grand multiparity, and induction of labor with oxytocin or prostaglandin
Which of the following changes occurring during pregnancy increases the risk for deep vein thrombosis?
Pregnancy is a prothrombotic state with increased levels of many clotting factors. Factors VII, VIII, IX, X, and XII levels are all increased. In addition there is a decrease in factor C & S levels. This causes shorter PT and PTT times. However, not all factors are increased during pregnancy with factors XI and XIII levels decreasing slightly.
TrueLearn Insight : When initiating warfarin therapy in the nonparturient, low molecular weight heparin is typically coadministered until the INR has reached a therapeutic level. This is done in order to prevent warfarin-induced paradoxical thrombosis. This may occur since warfarin also inhibits production of the anticoagulant protein C. Warfarin is contraindicated in the parturient due to teratogenicity.
During which of the following times is maternal cardiac output the highest?
Maternal cardiac output progressively increases during pregnancy and throughout labor, reaching its peak immediately following delivery (2.5x prepregnancy values). Cardiac output then quickly declines postpartum and begins to approach prepregnant values by two weeks postpartum.
At one minute of life after emergency cesarean delivery for prolonged fetal bradycardia, a neonate is cyanotic, has some extremity flexion, and has a feeble cry following oropharyngeal suctioning. The heart rate is 110 and respirations are slow and irregular. What is the neonate’s Apgar score?
0 1 2
Skin color Cyanotic Acrocyanotic (pink chest, cyanotic extremities) Pink
Heart rate Absent < 100 bpm >100 bpm
Reflex irritability No response to stimulation Grimace and/or feeble cry when stimulated Active, strong response to stimulation
Muscle tone Absent, limp Some extremity flexion Active movement
Breathing Absent Weak, irregular, slow, shallow, or gasping Strong, regular, crying
