Adjunct Fetal Assessment Flashcards

A patient's EFM tracing shows a persistent Category II pattern with minimal variability and no spontaneous accelerations for 40 minutes. Intrauterine resuscitation measures have not resolved the pattern. Which adjunct assessment method is most appropriate to evaluate for fetal acidemia?

Answer: Fetal scalp stimulation

Fetal scalp stimulation (FSS) is used to elicit a fetal heart rate acceleration. The presence of an FHR acceleration after stimulation is a reassuring sign that reliably predicts the absence of fetal metabolic acidemia. Amnioinfusion is used for recurrent variable decelerations, terbutaline is a tocolytic for tachysystole, and Montevideo units quantify uterine contraction strength, none of which directly assess for acidemia in this context.

At birth, a clamped segment of the umbilical cord is collected for blood gas analysis. Which vessel provides the most accurate information regarding the fetal metabolic state at the time of delivery?

Answer: Umbilical artery

The umbilical artery carries deoxygenated blood and metabolic waste products away from the fetus to the placenta. Therefore, its blood gas values most accurately reflect the fetal acid-base status at the moment of birth. The umbilical vein carries oxygenated blood from the placenta to the fetus and is more reflective of placental function.

Amnioinfusion is an appropriate intervention for which of the following clinical scenarios?

Answer: Recurrent severe variable decelerations

Amnioinfusion involves instilling a sterile, warmed isotonic fluid into the uterine cavity. Its primary indication is to relieve recurrent variable decelerations caused by umbilical cord compression, as the fluid provides cushioning. It is not indicated for late decelerations, tachycardia, or sinusoidal patterns, which are related to uteroplacental insufficiency or severe fetal anemia.

A clinician performs vibroacoustic stimulation (VAS) on the maternal abdomen for a term fetus with a nonreactive non-stress test. What response on the EFM tracing would be considered reassuring?

Answer: An acceleration of at least 15 bpm for 15 seconds

A reassuring response to vibroacoustic stimulation (VAS) is a fetal heart rate acceleration. For a fetus at or beyond 32 weeks gestation, this is defined as a visually apparent increase in the FHR of at least 15 beats per minute (bpm) above the baseline, lasting for at least 15 seconds. This response indicates an intact and non-acidotic central nervous system.

Analysis of an umbilical artery cord blood gas sample yields the following results: pH 7.15, pCO2 70 mmHg, Base Deficit -4 mmol/L. How should these findings be interpreted?

Answer: Respiratory acidemia

This blood gas shows a low pH (acidemia) and a high pCO2 (respiratory component), with a normal base deficit (no significant metabolic component). This combination is characteristic of respiratory acidemia, which is caused by the accumulation of carbon dioxide.

Which of the following is a recognized contraindication for performing fetal scalp stimulation?

Answer: Maternal active genital herpes infection

Fetal scalp stimulation is contraindicated in the presence of maternal infections that can be transmitted to the fetus through a break in the skin, such as active genital herpes or HIV. Other contraindications include significant prematurity, placenta previa, and fetal bleeding disorders. Moderate variability and a term, cephalic fetus are normal findings and not contraindications.