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Exam 3 Knowledge Checks (Intrapartum, Perfusion, Preeclampsia)

Terms in this set (114)

Intermittent auscultation promotes the laboring woman's mobility and creates a more natural atmosphere. However, assessment of the fetus is intermittent—significant events may not be detected, periodic and nonperiodic changes in fetal heart rate (FHR) cannot be determined, the patient may be intolerant of the clinician's touch during contractions, and contractions cannot be assessed objectively. Continuous electronic fetal monitoring provides more data, is often expected by parents, and can assist the nurse to better observe more than one woman. It allows the nurse to devote more time to coaching the woman and her partner. Its primary drawbacks are reduced maternal mobility, adjustments to the equipment, and its technical atmosphere. When using external transducers (ultrasound/tocotransducer), the FHR may be doubled or halved in cases of fetal bradycardia or tachycardia, the maternal heart rate may be recorded as fetal data if the ultrasound transducer is placed over maternal arterial vessels, obese women and preterm or multifetal gestations may be difficult to monitor, and the tocotransducer does not accurately assess the intensity of contractions or resting tone of the uterus between contractions. Internal monitors (fetal scalp electrode [FSE]/intrauterine pressure catheter [IUPC]) are not usually affected by maternal position changes (although the IUPC needs to be recalibrated with maternal position changes) and accurately measure all parameters of uterine activity. However, they require cervical dilatation, and ruptured fetal membranes can cause trauma and infection.
Late decelerations are visually apparent and usually symmetric in shape, with a gradual decrease and return of the fetal heart rate (FHR) to baseline. Late decelerations occur when the onset of the deceleration to the nadir is equal to or greater than 30 seconds, and the nadir of the deceleration occurs after the peak of the contraction. Late decelerations that occur in the presence of fetal heart rate variability indicate transient fetal hypoxia caused by an interruption along the oxygen pathway. Once corrective measures are initiated, they will typically resolve. Late decelerations are more concerning when they are recurrent and associated with tachycardia and a loss of variability. If uncorrected, hypoxic stress will lead to acidemia and neonatal depression.
Early decelerations are visually apparent, are symmetric in shape, and have a gradual decrease and return to FHR baseline that mirrors a uterine contraction. The deceleration onset, nadir, and recovery coincide with the beginning, peak, and ending of a contraction. The onset of the deceleration to the nadir is equal to or greater than 30 seconds. Early decelerations are thought to represent a vagal response during fetal head compression. Early decelerations are benign and not associated with an interruption of fetal oxygenation.
Variable decelerations are visually apparent, abrupt decreases from onset to nadir of a deceleration. The onset of the deceleration to the nadir is less than 30 seconds. The decrease is at least 15 bpm below the baseline, with the deceleration lasting at least 15 seconds and no longer than 2 minutes from onset to the return to baseline. Deceleration shape, depth, duration, and timing in relationship to contractions may vary. Variable decelerations are suggestive of an interruption of oxygenation at the level of the umbilical cord where cord vessels may be compressed. Generally, variable decelerations are not associated with significant hypoxia or acidosis as long as they are intermittent and accompanied by normal baseline rate and variability. If cord compression is recurrent or prolonged, interruption in fetal oxygenation can progress to hypoxemia, hypoxia, metabolic acidosis, and final metabolic acidemia if corrective measures are not successful.