Chapter 22 - Vicky - Fall 16

How should the therapist interpret a lecithin-to-sphingomyelin (L:S) ratio of 2:1? a. The presence of lung maturity b. A gestational age of less than 28 weeks c. The likelihood of RDS d. Laboratory error

ANS: A Lecithin, also known as dipalmitoyl phosphatidylcholine, is the most abundant phospholipid found in surfactant. RDS is unlikely if the L:S ratio is 2.0 or greater. REF: p. 412

Blood samples are simultaneously obtained from both the right radial artery and the umbilical artery, and the arterial partial pressure of oxygen (PaO2) value from the right radial artery is 20 mm Hg greater than that analyzed from the umbilical artery sample. On the basis of this finding, which of the following conditions does the neonate likely have? a. PPHN b. MAS c. Neonatal pneumonia d. RDS

ANS: A A PaO2 gradient between a preductal (right radial artery) and a postductal (umbilical artery) site of blood sampling >20 mm Hg suggests right-to-left shunting through the ductus arteriosus, as does an oxygenation saturation gradient >5% between preductal and postductal sites on pulse oximetry. REF: p. 435

Which of the following medications should the therapist recommend for an infant with apnea of prematurity experiencing episodes of apnea? a. Caffeine b. Benzodiazepines c. Antibiotics d. Doxapram

ANS: A Caffeine's proposed mechanisms include stimulation of skeletal and diaphragmatic muscle contraction, increase in the respiratory center's sensitivity to carbon dioxide, and stimulation of the central respiratory drive. Caffeine appears to be a safer drug, can be given less frequently than aminophylline or theophylline, and is more effective in treating apnea. REF: p. 438

When should a therapist consider CPAP for a newborn with respiratory distress? a. FiO2 > 40% to 70% and SpO2 < 85% b. FiO2 > 90% and SpO2 < 95% c. Respiratory rate of 40 breaths per minute d. PaO2 50 to 60 mm Hg

ANS: A If oxygen saturation cannot be kept > 85% at inspired oxygen concentrations of 40% to 70% or greater, continuous positive airway pressure (CPAP) via nasal prongs or nasopharyngeal tube using a continuous-flow ventilator may be instituted. REF: p. 415

What is the typical type of airway obstruction that occurs with MAS? a. Ball valve b. Complete c. No obstruction d. Airway inflammation

ANS: A If the infant has a large amount of thick meconium within the airways at the time of delivery, complete bronchiole obstruction with subsequent alveolar collapse will result. The more typical picture, however, is that of smaller amounts of meconium within amniotic fluid, causing a ball-valve effect because of partial obstruction of the airways. REF: p. 429

The therapist is assessing a newborn on the mechanical ventilator. The neonate shows clear signs of respiratory distress, and lung auscultation reveals shifting of the PMI towards the left and breath sounds decreased on the right. What should the therapist suspect this newborn developed? a. Right-sided pneumothorax b. Severe right lung atelectasis c. Right pleural effusion d. Left-sided atelectasis

ANS: A Neonates with spontaneous pneumothorax are usually asymptomatic or have mild signs of tachypnea with an oxygen requirement. Occasionally, severe respiratory distress (grunting, nasal flaring, and intercostal retractions) may occur. In the ventilated neonate, pneumothorax may lead to a rapid clinical deterioration, resulting in cyanosis, hypotension, hypoxemia, hypercapnia, and respiratory acidosis. In unilateral pneumothorax, the cardiac apex can be shifted away from the affected side and breath sounds decreased over that side. REF: p. 439

What is the significance of an infant with RDS demonstrating a grunt during each exhalation? a. Resolution of the RDS b. An effort to maintain its functional residual capacity (FRC) c. An attempt to overcome increased airway resistance d. Impending death

ANS: B A characteristic grunt during expiration is an attempt to maintain the FRC. REF: p. 412

In addition to Group B Streptococcus, which of the following microorganisms are responsible for nosocomial pneumonia acquired after delivery? a. RSV b. Escherichia coli c. Pseudomona spp. d. Haemophilus influenza

ANS: B Bacteria that should be considered when pneumonia is acquired in utero or in the immediate perinatal period include Escherichia coli, Klebsiella spp., Group D Streptococci, Listeria monocytogenes, and pneumococci acquired via transmission from the mother. REF: p. 425

What ventilator settings should a therapist select for a newborn with respiratory distress syndrome? I. PIP 25-30 cm H2O II. PEEP 3-6 cm H2O III. VT 5-6 mL/kg IV. Frequency 60 breaths per minute a. I and II only b. II only c. I, II, and III only d. I, II, III, and IV

ANS: B Generally, once the infant is stabilized and in the NICU, a pressure-limited ventilator utilizing a sinusoidal flow pattern is used. Peak inspiratory pressures (PIPs) generally begin at 15 to 25 cm H2O, depending on the size of the infant and the severity of the disease, to establish a tidal volume (VT) between 3 and 5 mL/kg. Positive end-expiratory pressure (PEEP) levels of 3 to 6 cm H2O are used to prevent further alveolar collapse, and rates of 20 to 50 breaths per minute are used to treat hypercapnia. Inspiratory times should be initiated at 0.3 to 0.4 second. If a longer inspiratory time is required before surfactant administration, it should be lowered to 0.3 second after surfactant is administered. REF: p. 415

The therapist is reviewing the chest radiograph of a newborn, preterm infant and observes diffuse, fine, reticulogranular densities, which provide a ground-glass appearance. On the basis of these radiographic findings, which of the following conditions should the therapist suspect is present? a. Persistent pulmonary hypertension of the newborn b. Respiratory distress syndrome c. Bronchopulmonary dysplasia d. Pulmonary interstitial emphysema

ANS: B The chest radiograph in RDS typically reveals diffuse, fine, granular (reticulogranular) densities, which present a ground-glass appearance. The heart may be slightly enlarged, and the thymus is nearly always visible. REF: p. 412

Which of the following therapeutic interventions is generally needed to treat transient tachypnea of the newborn (TTN)? a. Endotracheal intubation b. 40% oxygen hood c. Bronchial hygiene therapy d. Bronchodilator therapy

ANS: B Treatment is largely supportive. The objectives of treatment of TTN are to maintain adequate oxygenation and ventilation. Supplemental oxygen via oxygen hood (usually < 40%) is indicated when signs of respiratory distress are present. CPAP levels of 3 to 5 cm H2O may be needed when higher FiO2 levels are required. REF: p. 425

Which of the following blood gas parameters should the therapist target when managing patients with PPHN? I. SaO2 > 95% II. PaCO2 35-45 mm Hg III. pH 7.35-7.45 IV. PaO2 > 95 mm Hg a. I only b. II and III only c. I, II, and III only d. II, III, and IV only

ANS: C Adjust ventilators to maintain adequate oxygenation and mild hyperventilation, until stability is achieved for 12 to 24 hours after initially attempting to keep the oxygen saturation above 95%, arterial carbon dioxide tension (PaCO2) at 35 to 45 mm Hg, and pH at 7.35 to 7.45. REF: p. 436

What is the incidence of respiratory distress syndrome (RDS) among infants born at less than 28 weeks of gestation? a. 30% to 40% b. 40% to 50% c. 60% to 80% d. >80%

ANS: C In the United States, respiratory distress syndrome (RDS) has been estimated to occur in 20,000 to 30,000 newborn infants each year and is a complication in about 1% of pregnancies. Its incidence is inversely related to gestational age and birth weight. It occurs in 60% to 80% of infants < 28 wk of gestational age, in 15% to 30% of those between 32 and 36 wk, and rarely in those > 37 wk. REF: p. 409

Why does meconium staining occur predominantly in infants older than 36 weeks of gestational age? a. Because these infants can generate strong inspiratory efforts b. Because infants this age have significant cardiac outputs c. Because these infants demonstrate strong peristalsis d. Because these newborns have weak anal sphincter tone

ANS: C Meconium passage into the amniotic fluid requires strong peristalsis and anal sphincter tone, which is not common in preterm infants. Meconium aspiration syndrome rarely occurs in infants born at less than 36 weeks of gestation. The longer a pregnancy is allowed to continue past 42 weeks, the greater the chances are of the passage of meconium. REF: p. 429

A newborn suspected of having a pneumothorax is rapidly deteriorating. What should the therapist suggest at this time? a. Intubation and mechanical ventilation b. Mask CPAP c. Needle aspiration d. Confirm air leak with a chest X-ray and place a chest tube afterwards

ANS: C Needle aspiration: In a rapidly deteriorating clinical situation, thoracentesis or pericardiocentesis may confirm the diagnosis and be therapeutic in pneumothorax and pneumopericardium, respectively. REF: p. 441

Which of the following risk factors contribute to the pathogenesis of BPD? I. Lung immaturity II. Respiratory failure III. Oxygen supplementation IV. Positive-pressure ventilation a. I and II only b. IV only c. I, II, III, and IV d. III and IV only

ANS: C Northway and colleagues proposed four major factors in BPD pathogenesis: (1) lung immaturity, (2) respiratory failure, (3) oxygen supplementation, and (4) positive-pressure mechanical ventilation. REF: p. 417

How should the therapist interpret the lack of supernatant foam appearing during the shake test? a. The test needs to be redone. b. The unborn infant's lungs have matured. c. The infant's lungs are immature. d. The patient has a 50% chance of developing RDS.

ANS: C Other tests for lung maturity have been developed; in the foam stability test, amniotic fluid is mixed with different volumes of 95% ethanol. When this mixture is shaken with air, a foam develops that can be seen for several hours at room temperature. If no surfactant is present, the foam will not appear or will appear only briefly, indicating the strong possibility of immature lungs. The shake test is not as specific as a low L:S ratio. REF: p. 412

Eight hours after being born, a baby presents with cyanosis despite administration of adequate ventilation, tachypnea, and retractions. Which of the following conditions should the therapist suspect is affecting this newborn? a. RDS b. BPD c. PPHN d. GBS pneumonia

ANS: C PPHN should be suspected in all term infants who have cyanosis that may occur despite adequate ventilation. The recognition of risk factors for PPHN is one of the major diagnostic tools to differentiate babies with PPHN from those with structural heart disease, keeping in mind that idiopathic PPHN can present without signs of acute perinatal distress. Marked lability in oxygenation is frequently part of the clinical history. The infant with PPHN usually presents within the first 12 hours of life with cyanosis, tachypnea, and hypoxia that are refractory to oxygen therapy, as well as signs of respiratory distress, including retractions, grunting, and nasal flaring. REF: p. 434

A neonate diagnosed with a pneumothorax was treated with a chest tube. After 36 hours, the therapist noticed that bubbling is present in the chest tube system. What should the therapist do at this time? a. Suggest removal of the chest tube in 24 hours b. Clamp the tube and obtain a CXR c. Keep the chest tube until bubbling stops d. Remove the chest tube and obtain a follow-up CXR

ANS: C Suction should be maintained until fluctuation of air in the tube and active bubbling have ceased. At this time the tube should be clamped and removed within 24 hours if there has been no reaccumulation of air in the pleural cavity. REF: p. 442

While reviewing the chest X-ray of a newborn, the therapist observes the following features: Pulmonary vascular congestion Prominent perihilar streaking Fluid in the interlobular fissures Hyperexpansion Flat diaphragm Which of the following conditions does this patient likely have? a. RDS b. Persistent pulmonary hypertension of the newborn c. Transient tachypnea of the newborn d. Barotrauma

ANS: C The chest radiograph shows pulmonary vascular congestion, prominent perihilar streaking, fluid in the interlobular fissures, hyperexpansion, and a flat diaphragm (see Figure 22-4 in the textbook). Mild cardiomegaly and pleural effusions may also be present. REF: p. 424

The therapist is contemplating the possibility of intubating and suctioning a nonvigorous newborn with MAS. Which of the following clinical parameters confirms the indication for the procedure? a. Good muscle tone b. Presence of dark green meconium on the skin c. Heart rate < 100 beats per minute d. Presence of coarse crackles on auscultation

ANS: C The guidelines are under continuous review and are revised as new evidence-based research becomes available. The current guidelines are as follows: If the baby is not vigorous (defined as depressed respiratory effort, poor muscle tone, and/or heart rate < 100 beats/min), use direct laryngoscopy, intubate, and suction the trachea immediately after delivery. Suction for no longer than 5 seconds. If no meconium is retrieved, do not repeat intubation and suction. If meconium is retrieved and no bradycardia is present, reintubate and suction. If the heart rate is low, administer positive pressure ventilation and consider suctioning again later. REF: p. 431

Which of the following conditions increase the risk for developing RDS? I. Maternal diabetes II. Cesarean delivery III. Multiple births IV. Premature rupture of membranes a. I only b. II and III only c. I, II, and III only d. II, III, and IV only

ANS: C The risk for development of RDS increases with maternal diabetes, multiple births, cesarean delivery, precipitous delivery (delivery of infant anywhere unintended), asphyxia, cold stress, and a maternal history of previously affected infants. REF: p. 409

While reviewing the chest X-ray of a newborn, the therapist observes the following features: continuous diaphragm sign and linear bands of air paralleling the left side of the heart and the descending aorta with extension superiorly along the great vessels into the neck. Which of the following conditions does this patient likely have? a. Pneumothorax b. Cardiac tamponade c. Pneumomediastinum d. Pneumopericardium

ANS: C Typical radiological signs of pneumomediastinum include the continuous diaphragm sign (interposition of air between the pericardium and the diaphragm, which becomes visible in the central mediastinal part) and linear bands of mediastinal air paralleling the left side of the heart and the descending aorta (pleura appears as a fine opaque line) with extension superiorly along the great vessels into the neck. REF: p. 440

When neonatal pneumonia is suspected, how long does an infant generally receive broad-spectrum antibiotics? a. 24 hours b. 48 hours c. 72 hours d. 96 hours

ANS: C Whenever neonatal pneumonia is suspected, broad-spectrum antibiotics are given for at least 72 hours, or until definitive culture results are obtained. If results prove that infection is present, antibiotics are continued for 14 to 21 days. REF: p. 428

When should a therapist consider intubation and mechanical ventilation for a newborn with respiratory distress? I. FiO2 > 40% to 70% II. SpO2 < 85% III. CPAP of 5-10 cm H2O IV. pH < 7.20 a. I and II only b. II and III only c. I, II, and III only d. I, II, III, and IV

ANS: D Classic indications for endotracheal intubation and mechanical ventilation are infants with respiratory failure or persistent apnea. Reasonable measures of respiratory failure are: (1) arterial blood pH < 7.20, (2) arterial blood PaCO2 of 60 mm Hg or higher, and (3) oxygen saturation <85% at oxygen concentrations of 40% to 70% and CPAP of 5 to 10 cm H2O. REF: p. 415

What radiographic features is the therapist likely to see on a typical chest X-ray of an infant with MAS? a. Ground-glass appearance b. Complete whiteout c. Decreased lung volume d. Patchy areas of atelectasis

ANS: D The typical chest radiograph shows patchy areas of atelectasis due to obstruction, as well as hyperexpansion from air trapping with flattening of the diaphragm sometimes noted on the radiograph. REF: p. 431