Answer to Question 1
ANS: B
A newborn with tachypnea, nasal flaring, a PaCO2 of 50 mm Hg, a PaO2 of 50 mm Hg, and an FIO2 of 0.6 meets the criteria for nasal CPAP. A newborn with these findings has adequate mi-nute ventilation, as evidenced by the PaCO2 of 50 mm Hg, but also has hypoxemia that is not be-ing corrected by an FIO2 of 0.6. The newborn in option A (substernal retractions, PaCO2 = 65 mm Hg, PaO2 = 48 mm Hg, FIO2 = 0.4) does not have an adequate minute ventilation and requires some ventilatory assistance. Mechanical ventilation is indicated for the newborn in option C (grunting, substernal retractions, pH = 7.20, PaCO2 = 70 mm Hg, PaO2 = 40 mm Hg, FIO2 = 0.7), because this patient has respiratory acidosis and uncorrected hypoxemia. The newborn in option D (tachypnea, pale skin, pH = 7.32, PaCO2 = 45 mm Hg, PaO2 = 75 mm Hg, FIO2 = 0.21) has two of the physical indications for CPAP, but the ABG findings demonstrate adequate oxygenation.
Answer to Question 2
ANS: B
The short binasal prongs are the most commonly used interface for infants receiving nasal CPAP. Nasal masks are slowly becoming more popular. The least popular method of administering CPAP is through nasopharyngeal or endotracheal tubes, because they are invasive.