Chapter 1: Fetal Lung Development Test Bank
MULTIPLE CHOICE 1. Which of the following phases of human lung development is characterized by the formation
of a capillary network around airway passages? Pseudoglandular Saccular Alveolar Canalicular
a. b. c. d.
ANS: D
The canalicular phase follows the pseudoglandular phase, lasting from approximately 17 weeks to 26 weeks of gestation. This phase is so named because of the appearance of vascular channels, or capillaries, which begin to grow by forming a capillary network around the air passages. During the pseudoglandular stage, which begins at day 52 and extends to week 16 of gestation, the airway system subdivides extensively and the conducting airway system develops, ending with the terminal bronchioles. The saccular stage of development, which takes place from weeks 29 to 36 of gestation, is characterized by the development of sacs that later become alveoli. During the saccular phase, a tremendous increase in the potential gasexchanging surface area occurs. The distinction between the saccular stage and the alveolar stage is arbitrary. The alveolar stage stretches from 39 weeks of gestation to term. This stage is represented by the establishment of alveoli. REF: pp. 3-5 2. Regarding postnatal lung growth, by approximately what age do most of the alveoli that will be present in the lungs for life develop? a. 6 months b. 1 year c. 1.5 years d. 2 years ANS: C
Most of the postnatal formation of alveoli in the infant occurs over the first 1.5 years of life. At 2 years of age, the number of alveoli varies substantially among individuals. After 2 years of age, males have more alveoli than do females. After alveolar multiplication ends, the alveoli continue to increase in size until thoracic growth is completed. REF: p. 6 3. The respiratory therapist is evaluating a newborn with mild respiratory distress due to
tracheal stenosis. During which period of lung development did this problem develop? a. Embryonal b. Saccular c. Canalicular d. Alveolar
ANS: A
The initial structures of the pulmonary tree develop during the embryonal stage. Errors in development during this time may result in laryngeal, tracheal, or esophageal atresia or stenosis. Pulmonary hypoplasia, an incomplete development of the lungs characterized by an abnormally low number and/or size of bronchopulmonary segments and/or alveoli, can develop during the pseudoglandular phase. If the fetus is born during the canalicular phase (i.e., prematurely), severe respiratory distress can be expected because the inadequately developed airways, along with insufficient and immature surfactant production by alveolar type II cells, gives rise to the constellation of problems known as infant respiratory distress syndrome. REF: p. 6 4. Which of the following mechanisms is (are) responsible for the possible association between
oligohydramnios and lung hypoplasia? I. Abnormal carbohydrate metabolism II. Mechanical restriction of the chest wall III. Interference with fetal breathingIV. Failure to produce fetal lung liquid a. I and III only b. II and III only c. I, II, and IV only d. II, III, and IV only ANS: D
Oligohydramnios, a reduced quantity of amniotic fluid present for an extended period of time, with or without renal anomalies, is associated with lung hypoplasia. The mechanisms by which amniotic fluid volume influences lung growth remain unclear. Possible explanations for reduced quantity of amniotic fluid include mechanical restriction of the chest wall, interference with fetal breathing, or failure to produce fetal lung liquid. These clinical and experimental observations possibly point to a common denominator, lung stretch, as being a major growth stimulant. REF: pp. 6-7 5. What is the purpose of the substance secreted by the type II pneumocyte? a. To increase the gas exchange surface area b. To reduce surface tension c. To maintain lung elasticity d. To preserve the volume of the amniotic fluid ANS: B
The primary role of mammalian surfactant is to lower the surface tension within the alveolus, specifically at the air–liquid interface. This allows the delicate structure of the alveolus to expand when filled with air. Without surfactant, the alveolus remains collapsed because of the high surface tension of the moist alveolar surface. Surfactant is composed predominantly of an intricate blend of phospholipids, neutral lipids, and proteins.
REF: p. 8 6. Which of the following tests of the amniotic fluid have been shown to be sensitive indicators
of lung maturity? a. Levels of prednisone b. Levels of epidermal growth factor c. Levels of prostaglandins d. Levels of phosphatidylglycerol and phosphatidylcholine ANS: D
Of clinical relevance during late gestation, analysis of amniotic fluid for the concentration of phosphatidylglycerol and phosphatidylcholine has been shown to be a sensitive indicator of the state of fetal lung maturity. REF: p. 8
Chapter 2: Fetal Gas Exchange and Circulation Test Bank
MULTIPLE CHOICE 1. Which of the following embryonic germ layers gives formation to the respiratory system? a. Endoderm b. Mesoderm c. Ectoderm d. Periderm ANS: A
The respiratory system—pharynx, lungs, and epithelial lining of the trachea and lungs— originates in the endoderm. Refer to Box 2-1 in the textbook to see the list of various tissue systems found in the three embryonic layers. REF: p. 13 2. What is the function of Wharton’s jelly inside the umbilical cord? a. To help provide nutrition to the fetus b. To prevent the vessels inside the cord from kinking c. To help protect the fetus d. To regulate the temperature between the fetus and the mother ANS: B
Wharton's jelly, a gelatinous substance inside the umbilical cord, helps protect the vessels of the fetus and may prevent the cord from kinking. REF: p. 13 3. Which of the following organs is considered to be the first to form? a. Heart b. Brain c. Lungs d. Kidneys ANS: A
The heart is considered to be the first complete organ formed. By 8 weeks of gestation, the normal fetal heart is fully functional, complete with all chambers, valves, and major vessels. REF: p. 14 4. A pregnant woman is coming for an early prenatal evaluation and wants to know if she can
listen to the baby’s heartbeat. How early can the fetal heartbeat be detected? a. Day 8 b. Day 22
c. Day 45 d. Day 60 ANS: B
By day 22 cardiac contractions are detectable and bidirectional tidal blood flow begins. REF: p. 14 5. Which of the following anatomic structures is a (are) fetal shunt(s)?
I. Foramen ovale II. Sinus venosus III. Ductus venosusIV. Ductus arteriosus a. b. I, III, and IV only c. I, II, and IV only d. II, III, and IV only
III only
ANS: B
Figure 2-6 in the textbook illustrates fetal circulation and the three shunts present in the fetus that close soon after birth. They include (1) the foramen ovale, the opening between the right atrium and the left atrium, which enables oxygenated blood to flow to the left side of the fetal heart; (2) the ductus venosus, which appears continuous with the umbilical vein and shunts 30% to 50% of oxygen-rich blood around the liver; and (3) the ductus arteriosus, which allows most of the pulmonary arterial blood flow to bypass the nonfunctioning fetal lungs and enter the aorta. REF: p. 17 6. Which of the following events causes cessation of right-to-left shunt through the
foramen ovale? a. Increased levels of PO2 in the blood of the neonate b. Decreased levels of PCO2 in the blood of the newborn c. Increased systemic vascular resistance d. Removal of the placenta, causing lowered blood volume returning to the right side of the fetal heart ANS: C
Once the cord is clamped and the PVR decreases, pressures in the right side of the heart decrease and pressures in the left side increase. Because the foramen ovale flap allows blood to flow only from right to left, it closes when the pressures in the left atrium become greater than those in the right atrium. Closing the foramen ovale further facilitates the increase of blood flow to the lungs during the transitional period and is necessary to maintain normal extrauterine circulation. REF: p. 18 7. How long after birth should it take for the ductus arteriosus to close completely? a. 24
hours b. 48 hours
c. 96 hours d. 1 week ANS: C
Because the pressure in the aorta also increases and becomes greater than the pressure in the pulmonary artery, the amount of shunting through the ductus arteriosus decreases. The functional closure of the ductus arteriosus occurs as a result of being exposed to an increased PO2, a decrease in PVR leading to the reduction in blood pressure within the ductal lumen, a decrease in the local production of prostaglandins, and a reduction in the number of prostaglandin receptors within the tissue of the ductus arteriosus. Normally, constriction of the ductus arteriosus starts to occur at birth, and 20% of the ductus closes within 24 hours, with 80% closed in 48 hours, and 100% by 96 hours after birth. REF: p. 18
Chapter 3: Antenatal Assessment and High Risk Delivery Test Bank
MULTIPLE CHOICE 1. A pregnant woman has been diagnosed with pregestational diabetes. Which of the following risk factors should the therapist be aware at the time of delivery? a. Unexplained abruption
placenta b. Oligohydramnios c. Microcephaly d. Fetal malformations ANS: C
Adverse fetal outcomes include unexplained fetal death in the third trimester of pregnancy and major fetal structural malformations. Close surveillance of the maternal metabolism and close fetal biophysical evaluation have significantly decreased the risk of fetal death as well as the necessity of delivering a fetus prematurely because of abnormal test results. The rate of fetal structural malformations in infants born to pregestational diabetic women can be as high as 10% to 15% compared with a rate of 1% to 2% for infants of otherwise normal women. The most frequently encountered defects include malformations of the cardiovascular system, including both the heart and great vessels, and the central nervous system, including the brain and spinal cord. No amount of maternal metabolic surveillance or fetal biophysical assessment after the period of fetal organogenesis will decrease this risk. Therefore, it is recommended strongly that women with diabetes mellitus receive counseling and treatment with the goal of achieving optimal glycemic control before they become pregnant. REF: p. 22 2. The respiratory therapist is attending a term labor of a woman diagnosed with gestational
diabetes. The baby is very large for gestational age. What other metabolic disturbances should be considered? I. Hyperglycemia II. Hypocalcemia III. Hyperkalemia IV. Hypoglycemia a. II and IV only b. I, II, and III only c. I and III only d. II, III, and IV only ANS: D
Poor blood sugar control in these women is associated with an increased risk of macrosomia (birth weight greater than 4000 g), traumatic vaginal delivery, preterm delivery, and a small
risk of fetal death in some women. After delivery, the infants are at increased risk for metabolic disturbances in the neonatal period; these include hypoglycemia, hypocalcemia, hyperkalemia, hyperbilirubinemia, and idiopathic respiratory distress syndrome. REF: p. 22 3. Which of the following microorganisms often affect pregnancy outcome? a. Group B Streptococcus b. Haemophilus influenzae c. Mycobacterium tuberculosis d. Hepatitis C virus ANS: A
A number of infectious agents can affect pregnancy outcome. Among the most important in the United States are group B Streptococcus (GBS), herpes simplex virus (HSV), human immunodeficiency virus (HIV), and hepatitis B virus (HBV). As many as 10% to 40% of pregnant women are colonized with GBS. Their infants are at risk for death or severe morbidity if they are born prematurely or after prolonged rupture of the fetal membranes. REF: p. 23 4.
What is generally accepted as a safe limit for alcohol consumption during pregnancy to avoid the development of fetal alcohol syndrome? a. One to two 8-ounce drinks per day are considered acceptable. b. Four to five 8-ounce drinks per week are considered safe. c. Three to four 12-ounce drinks per week are considered reasonable. d. No safe range of alcohol consumption is deemed safe during pregnancy. ANS: D
Alcohol is a potent teratogen, an agent or factor that causes malformation in the fetus. Fetal alcohol syndrome, associated with maternal use of alcohol in pregnancy, is characterized by mental retardation and prenatal and postnatal growth restriction, as well as by brain, cardiac, spinal, and craniofacial anomalies. It is usually seen among children of women who consume four to six alcoholic drinks daily throughout pregnancy. However, no safe range of alcohol consumption during pregnancy exists. REF: p. 24 5.
What is the average birth weight difference between infants born of mothers who smoke and those born of nonsmoking mothers? a. Infants born of mothers who smoke tend to be about 200 g lighter than infants born of mothers who do not smoke. b. Infants born of mothers who smoke are generally about 400 g lighter than infants born of nonsmoking mothers. c. Infants born of mothers who smoke are predisposed to weigh approximately 600 g less than infants born of mothers who do not smoke. d. Infants of mothers who smoke are likely to be born about 800 g lighter than those born of mothers who do not smoke.
ANS: A
The mean birth weight of infants of women who smoke during pregnancy is about 200 g less than that of infants of nonsmokers. REF: p. 24 6.
A woman with a long history of smoking is now in the last part of the third trimester of her pregnancy. She is at high risk for which of the following conditions? I. Premature rupture of membranes II. Placental abruption III. Placenta previa IV. Sudden infant death syndromea. II and IV only b. I, II, and III only c. I and III only d. I, II, III, and IV ANS: D
Smoking is associated with a higher incidence of preterm premature rupture of membranes (rupture of the membranes before the onset of labor—before 37 weeks of gestation), placental abruption (separation of the placenta before birth of the newborn), and placenta previa (the placenta partially or completely covers the cervix), and risk of infant death from sudden infant death syndrome, (the unexplained death of an infant under 1 year of age). REF: p. 24 7.
Which of the following conditions are associated with preeclampsia? I. Multiparity II. Proteinuria III. Generalized edemaIV. Hypertension a. b. I, II, and III c. I, III, and IV d. II, III, and IV
II and III
ANS: D
Preeclampsia is a pregnancy-specific multisystem disorder traditionally diagnosed as the onset or exacerbation of hypertension, proteinuria, and edema in the second half of pregnancy. It complicates approximately 5% to 8% of pregnancies. REF: p. 24 8.
What is the main potential problem associated with the premature rupture of membranes? a. Fetal dehydration b. Fetal infection c. Maternal hypotension d. Maternal renal failure ANS: B
In utero, the fetus is contained in the sterile fluid-filled amniotic sac. If the membranes that compose the external lining of the amniotic sac rupture before term (before 37 weeks of gestation) or before the onset of normal labor at term, the fetal environment is no longer sterile, increasing the risk of fetal infection. REF: p. 25 9.
Which of the following conditions is responsible for up to 40% of the preterm births in the United States? a. Cervical insufficiency b. Premature rupture of the fetal membranes c. Obstetrical intervention mandated by fetal jeopardy d. Hormonal treatment during pregnancy ANS: B
The causes of premature rupture of the fetal membranes are generally not known but are responsible for 35 percent to 40 percent of preterm births in the United States. Preterm rupture of the fetal membranes can be seen as being responsible for all of the problems faced by most prematurely born infants. REF: p. 25 10. How should the therapist interpret an amniotic fluid index of 5 cm? a. Polyhydramnios b. Multihydramnios c. Oligohydramnios d. Anhydramnios ANS: C
The amniotic fluid index (AFI) is calculated by measuring the largest vertical pockets of fluid in each of the four uterine quadrants at the time of ultrasound examination. Oligohydramnios, too little amniotic fluid or an AFI below 5 cm, is usually associated with congenital anomalies (especially renal agenesis or urinary tract obstruction), fetal growth restriction or demise, postterm pregnancy, ruptured membranes, uteroplacental insufficiency, and use of prostaglandin synthase inhibitors. REF: p. 25 11. Once preterm labor is diagnosed, which of the following medications should be considered as
tocolytic? a. Magnesium sulfate b. Sodium bicarbonate c. Calcium carbonate d. Epinephrine ANS: A
Once preterm labor is diagnosed, prompt measures should be taken to try to stop labor and prevent an early delivery. Intravenous hydration is commonly the first approach used. However, it does not seem to be of clinical significance in a well-hydrated patient. Excessive
hydration should be avoided because it might exacerbate the risk of pulmonary edema that is usually associated with use of tocolytics. The most commonly used tocolytics are magnesium sulfate, beta-mimetic agents, and indomethacin (a prostaglandin inhibitor). Less commonly used are nifedipine (calcium channel blocker), nitroglycerin (nitric oxide donor drug), atosiban (oxytocin antagonist), and combination therapy. REF: p. 27 12. A pregnant woman at 30 weeks of gestation with premature rupture of membranes has been
admitted to the hospital with preterm labor. The physician has ordered betamethasone. When does the maximal benefit of antenatal corticosteroid occur to reduce RDS? a. After 12 hours b. After 24 hours c. After 48 hours d. After 1 week ANS: C
All women between 24 and 34 weeks of gestation with preterm labor and intact membranes are candidates for antenatal corticosteroid therapy. Patients with preterm labor and ruptured membranes benefit from corticosteroid therapy between 24 and 32 weeks of gestation. Betamethasone and dexamethasone are most commonly used for antenatal corticosteroid therapy. Maximal benefit occurs 48 hours after initiation of therapy and lasts for 7 days. REF: p. 27 13. Which of the following conditions is a significant problem in postterm pregnancy? a.
Infection b. Fetal anencephaly c. Meconium aspiration d. Obesity ANS: C
Meconium aspiration is a significant problem. Meconium passage in utero is common after 42 weeks of gestation. It is frequently associated with fetal hypoxia. Meconium becomes more concentrated in the amniotic fluid when associated with oligohydramnios. Aspiration of meconium may lead to obstruction of the respiratory passages and interference with surfactant function. REF: p. 28 14. A woman 41-weeks pregnant is at high risk for complication in the postpartum period. Which of the following agents will be more appropriate to induce labor? a. Magnesium sulfate b. Aspirin c. Terbutaline d. Oxytocin ANS: D
Labor induction can be achieved with various medications when the cervix is favorable for induction. Intravenous infusion of oxytocin, a hormone secreted from the posterior pituitary that stimulates uterine contractions and milk letdown, is most commonly used. REF: p. 29 15. What is the most common invasive procedure to assess the fetal condition? a. Amniocentesis b. Scalp fetal pH c. Stress test d. Needle ultrasound ANS: A
The most commonly performed invasive procedure to assess fetal condition is amniocentesis. In this procedure, under sterile conditions a needle is inserted through the skin and uterine wall to obtain a sample of fluid from the amniotic sac (see Figure 3-3 in the textbook). Depending on the reason for performing the procedure, the concentration of many substances in the fluid can be measured. For example, as the fetal lung matures, pulmonary surfactant is secreted from the fetal lung into the amniotic fluid, where its concentration can be measured. Fetal cells isolated from amniotic fluid can be used to assess for fetal chromosomal abnormalities (e.g., trisomy 21), fetal enzyme deficiencies (e.g., Tay-Sachs), and certain discrete genetic mutations (e.g., sickle cell disease). REF: p. 29 16. The respiratory therapist is called to assist in the labor of a pregnant woman whose NST
reported two accelerations in fetal heart rate, each of at least 15 beats per minute and lasting at least 15 seconds, associated with maternal perception of fetal movement over a period of 20 minutes. What is the best course of action? a. A C-section should be scheduled as soon as possible. b. No action is required because this reactive NST is associated with normal uteroplacental function. c. A CST should be performed before fetal stress is confirmed. d. Oxytocin should be to be administered to prevent more fetal stress. ANS: B
A reactive NST requires at least two accelerations in fetal heart rate, each of at least 15 beats per minute and lasting at least 15 seconds, associated with maternal perception of fetal movement over a period of 20 minutes. A reactive NST is highly correlated with normal uteroplacental function. REF: p. 30 17. A fetus is undergoing a contraction stress test. Uterine contractions are stimulated by the
intravenous infusion of oxytocin into the mother. The fetal PO2 drops below 12 mm Hg and causes the fetal heart rate to slow. Which of the following conditions is likely indicated by this occurrence? a. Placenta abruption