Free NP Neonatal Practice Test
1. A neonate receiving mechanical ventilation has a PaCO2 rate of 33 mm Hg with pH of 7.5 from a blood sample obtained from the umbilical artery. These values indicate:
a. metabolic acidosis from decreased tissue perfusion
b. respiratory acidosis from hypoventilation
c. respiratory alkalosis from hyperventilation
2. If a patient's membranes rupture and meconium-stained amniotic fluid is noted, the next step should be:
a. fetal scalp blood sampling
c. increased fetal monitoring
3. A full-term neonate fails to pass meconium in the first 48 hours of life. The infant exhibits abdominal distension, poor feeding, and bilious vomiting. An x-ray of the abdomen shows dilated loops of bowel. The diagnostic procedure used both to confirm a diagnosis of meconium plug syndrome and to treat is:
c. contrast enema
4. If a mother suffers from pregnancy-induced hypertension (pre-eclampsia) during pregnancy, the primary detrimental effect on the fetus is:
a. intrauterine growth retardation (IUGR)
b. placental abruption
c. spontaneous abortion
5. On examining the neonate, the neonatal nurse practitioner notes 9 cafe au lait spots with a diameter greater than 5 mm and freckles on the axilla and inguinal area. The infant should be tested for:
a. neurofibromatosis type 1
b. Sturge-Weber syndrome
c. Addison's disease
Answers & Explanations
1. C: These values indicate respiratory alkalosis from hyperventilation associated with excessive mechanical ventilation, which decreases the level of carbon dioxide. Respiratory alkalosis occurs with PaCO2 <35 and pH >7.45. Normal PaCO2 is 35-45 mm Hg and normal pH 7.35-7.45. Arterial blood gas (ABG) is the most informative measurement of blood gas status. Venous blood gas (VBG) is easier to obtain if an arterial catheter is not in place. To compare the values in the VBG with an ABG, add .05 to the pH of the VBG. Subtract 5-10 mm/Hg from the PCO2 of the VBG. Capillary blood gas (CBG) can be obtained with a heel stick, but the values obtained are the least accurate and rarely useful.
2. B: Meconium-stained amniotic fluid is an indication for immediate Caesarean to decrease the risk of meconium aspiration. Immediately following birth: If the infant is crying and showing no signs of distress, the mouth, nose and throat should be suctioned. If the infant shows signs of respiratory distress in the presence of meconium-stained fluid, the infant should be immediately intubated with an endotracheal tube for the purpose of suctioning the trachea. Once the airway has been adequately suctioned and cleared, the stomach may need to be suctioned as well in order to prevent the regurgitation of the swallowed meconium.
3. C: A contrast enema is used to confirm a diagnosis of meconium plug syndrome and helps differentiate that from other causes of intestinal obstruction. The contrast enema also is often therapeutic and helps the plug to pass. Meconium plug syndrome usually occurs in full-term infants, infants of diabetic mothers, or infants with hypermagnesemia. A small percentage of infants initially identified as having meconium plug syndrome (5 to 10%) have Hirschsprung disease. The cause of meconium plug syndrome is thought to be immaturity of the ganglion cells of the colon.
4. A: Pregnancy-induced hypertension (also called pre-eclampsia or toxemia) is a disorder that develops in approximately 5% of all pregnancies. Its main features are elevated blood pressure and proteinuria that develop around 20 weeks of gestation. The main detrimental effect on the fetus occurs because of longstanding hypertension that leads to utero-placental vascular insufficiency, which impairs the transfer of nutrients and oxygen to the fetus, resulting in intra-uterine growth retardation (IUGR). The IUGR is usually asymmetric (fetal head size is normal for gestational age). Placental abruption also occurs more frequently.
5. A: Cafe au lait spots (CAL) are flat skin lesions with increased melanin content and regular or irregular borders. If the CAL spots are faint, one can use a Wood lamp to make them easier to see. Fewer than 3 cafe au lait spots have no clinical significance. However, 6 or more cafe au lait spots with a diameter larger than 5 mm occur in 95% of patients with neurofibromatosis type 1 (NF1), a disorder of chromosome 17. Lisch nodules on the child's iris and Crowe's sign (freckles on the axilla and inguinal area) corroborate the diagnosis of NF1.
Last Updated: 07/05/2018