PEDS

Question 1

567. A 1-month-old infant with a strong family history of sickle-cell anemia is brought to the emergency room with an incarcerated inguinal hernia. Which of the following should be carried out before surgery?
     A. Sickle cell prep
     B. Hemoglobin electrophoresis
     C. Peripheral smear
     D. Hematology consultation E. Noneoftheabove

Answer 1

567. (E)
     Answers, References, and Explanations
     At birth, the concentration of hemoglobin F (fetal hemoglobin) is about 80% and reaches its lowest level by 2 to 3 months of age. Sickle-cell anemia (hemoglobin SS) is an inherited disorder of the β-chain of the adult hemo- globin molecule caused by a single amino acid substitution. It has an incidence of about 0.2% in the African- American population, in contrast to the relatively benign heterozygous condition, sickle cell trait (hemoglobin AS), which affects 8% to 10% of the same group. Sickling can occur in homozygous patients who become hypoxic, acidotic, hypothermic, or dehydrated. The predominant hemoglobin in this 1-month-old infant is hemoglobin F, which would temporarily protect the infant from the manifestations of sickle-cell anemia were he or she homozygous for hemoglobin S. The patient should, however, be worked up for sickle-cell anemia at some point in early life, but such a workup is not a prerequisite for surgery at 1 month of age (Miller: Anesthesia, ed 6, pp 1112-1113; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 49, 397-398; Stoelting: Anesthesia and Co-Existing Disease, ed 5, pp 411-412).

Question 2

568. In the newborn, the cricoid cartilage is at which level relative to the cervical spine? A. C3
     B. C4 C. C5 D. C6 E. C7

Answer 2

(B)The anatomy of the oropharynx and larynx of the newborn is different from that of the adult in many aspects. These differences may make it more difficult for a successful direct laryngoscopy and tracheal intubation. New- borns have larger arytenoids and tongue, and the lower border of the cricoid cartilage is at the level of the fourth cervical vertebra. (At age 6 years the cricoid cartilage is opposite the fifth cervical vertebra and in adults the cricoid cartilage is opposite the sixth cervical vertebra.) Additionally, the epiglottis of the infant is relatively larger and stiffer compared with the adult (Barash: Clinical Anesthesia ed 5, p 1186; Miller: Anesthesia, ed 6, pp 1646-1647; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 339).

Question 3

569. A 5-month-old infant is scheduled for an elective operative reduction of a right inguinal hernia. Spinal anesthesia is performed. The first sign of a high spinal in this patient would be
     A. Hypotension
     B. Tachycardia
     C. Hypoxia D. Bradycardia E. Asystole

Answer 3

569. (C)Spinal anesthesia can be administered safely to children of all ages. Hypotension secondary to a loss of sympa- thetic tone, common in the adult, is rare in the child younger than 5 years even with levels of T-3. Because of this hemodynamic stability, some pediatric anesthesiologists start an IV line after the spinal anesthetic is admin- istered to the infant. Respiratory depression including apnea and hypoxia will likely be the initial symptom asso- ciated with a high spinal anesthetic in the infant (Barash: Clinical Anesthesia, ed 5, pp 1191-1192; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 465-468).

Question 4

570. What percentage of a term newborn’s total body weight consists of water? A. 25%
     B. 40% C. 60% D. 75% E. 90%

Answer 4

570. (D)The body compartment volumes change with age. Muscle contains about 75% water, whereas adipose tissue contains only 10% water. Total body water (TBW) decreases with age as muscle and fat content increases. The fraction of total body weight that consists of water is 80% to 85% in premature newborns, 75% in term new- borns, and 60% in 6-month-old infants and in adults. These alterations in body composition have implications on the volume of distribution and redistribution of drugs (Miller: Anesthesia, ed 6, pp 1764, 2371; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 115-116).

Question 5

571. What is the maximum Fio2 that can be administered to the mother without increasing the risk of retinopathy of pre- maturity in the fetus in utero?
     A. 0.35 B. 0.50 C. 0.65 D. 0.80 E. 1.0

Answer 5

571. (E)The fetal Pao2 does not increase above 45 mm Hg when 100% O2 is administered to the mother because of the high O2 consumption of the placenta and uneven distribution of the maternal and fetal blood flow in the placenta. For these reasons, the Fio2 administered to the mother is not a factor in the etiology of retinopathy of prematurity in utero (Hughes: Shnider and Levinson’s Anesthesia for Obstetrics, ed 4, p 222).

Question 6

572. Which of the following patients is LEAST likely to develop retinopathy of prematurity?
     A. A term infant, 46 weeks postconceptual age, exposed to 100% oxygen for 6 hours
     B. A premature infant 29 weeks postconceptual age exposed to a Pao2 of 150 mm Hg for 1 hour
     C. A premature infant 28 weeks postconceptual age never exposed to supplemental oxygen
     D. A cyanotic infant with tetralogy of Fallot, 34 weeks postconceptual age, receiving supplemental oxygen E. Aterminfantat39weekspostconceptualagereceiving100%oxygenfor2hoursafterbirth

Answer 6

572. (A)Retinopathy of prematurity (ROP), formally called retrolental fibroplasia, typically occurs in newborns who are born at less than 35 weeks of gestational age. The risk of ROP is inversely related to age and birth weight, with a significant risk occurring in infants weighing less than 1500 g. The risk is negligible after 44 weeks postcon- ceptional age. The mechanism for retrolental fibroplasia is complex and is related to the complicated process of retinal development and maturation. Under normal circumstances, retinal vasculature develops from the optic disk toward the periphery of the retina. This process is typically complete by 40 to 44 weeks of gestation. Hyperoxia causes constriction of the retinal arterioles, resulting in swelling and degeneration of the endothe- lium that disrupts normal retinal development. Vascularization of the retina resumes in an abnormal fashion when normoxic conditions return, resulting in neovascularization and scarring of the retina. In the worst-case scenario, this process can lead to retinal detachment and blindness. Consequently, hyperoxia should be avoidedwhen anesthetizing preterm infants. Exposure of preterm infants to Pao2 greater than 80 mm Hg for prolonged periods may be associated with increased incidence and severity of retinopathy. To reduce this risk, it is recom- mended that the oxygen saturation be maintained between 93% and 95% (about Pao2 of 70 mm Hg) during anesthesia. On the other hand, one must never compromise O2 delivery to the neonate’s brain to protect the eyes. Although oxygen has been associated with ROP, other factors are also important. In fact, newborns with cyanotic congenital heart disease who have not been exposed to supplemental oxygen therapy have also devel- oped ROP (Barash: Clinical Anesthesia, ed 5, p 1193; Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 588-589; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 781-782).

Question 7

573. A 5-week-old male infant is brought to the emergency room with projectile vomiting. At the time of admission the patient is lethargic with a respiratory rate of 12 breaths/min and has had no urine output in the preceding 3 hours. A diagnosis of pyloric stenosis is made and the patient is brought to the operating room (OR) for pyloromyotomy. The most appropriate anesthetic management would be
     A. Induction with IM ketamine, glycopyrrolate, and succinylcholine with cricoid pressure followed by immediate intubation
     B. Inhalation induction with halothane with cricoid pressure
     C. Awake intubation
     D. Awake saphenous IV catheter followed by rapid sequence induction with ketamine, atropine, and succinylcholine
     E. Postponesurgery

Answer 7

573. (E)This patient has signs consistent with severe dehydration and needs resuscitation with fluid and electrolytes before surgery. Surgery should be delayed until there is thorough evaluation and treatment of the fluid and electrolyte imbalances. Pyloric stenosis occurs in approximately 1 in every 500 live births, making it the most common cause of gastrointestinal obstruction in pediatric patients. Pyloric stenosis occurs as frequently in preterm as in term neonates and there is a predilection for male infants. Persistent vomiting usually manifests itself between the second and sixth weeks of age and can result in dehydration, hypokalemia, hypochloremia, and metabolic alkalosis. Fluid resuscitation should be initiated with isotonic saline. If an IV line catheter cannot be established, an intraosseous needle should be placed. After the patient voids, potassium then can be safely added to the IV fluids. Once there has been adequate hydration and correction of the electrolyte and acid-base abnormalities, the patient can undergo surgery. Although several days may be required to restore normal fluid and electrolyte balance in some children, most respond within 12 to 48 hours (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 599-600; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 690-691).

Question 8

574. Which figure of esophageal atresia or tracheoesophageal fistula is the most common?

Answer 8

574. (C)Esophageal atresia (EA) and tracheoesophageal fistulas (TEFs) result from failure of the esophagus and the trachea to completely separate during development. This lesion occurs with an incidence of approximately 1 in 4000 live births. Although each of the listed answers is possible, the most common type is esophageal atresia with the lower segment of the esophagus communicating with the back of the trachea. This occurs in about 90% of all TEFs. In the delivery room, one is unable to pass a suction catheter into the stomach and if an x-ray is taken, the presence of air in the stomach suggests a fistula between the trachea and the stomach. If it is not detected in the delivery room, the newborn tends to have excessive oral secretions and is unable to feed. Note: 20% to 25% of patients with EA or TEF have associated cardiovascular anomalies (e.g., ventricular septal defect (VSD), atrial septal defect (ASD), tetralogy of Fallot, atrioventricular (AV) canal, coarctation of the aorta) (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 595-596; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 550-552).

Question 9

575. A 4-year-old boy is scheduled for completion of a hypospadias repair. The child is anxious. He has a history of a viral illness with a cough 2 weeks before surgery that has resolved. Anesthesia is induced with halothane, nitrous oxide, and oxygen. During the inhalation induction the patient’s rhythm changes from sinus tachycardia to multifocal ventricu- lar ectopy. The most likely explanation for this patient’s heart rhythm is
     A. Undiagnosed viral myocarditis B. Hypoxia
     C. Halothane irritability
     D. Pheochromocytoma
     E. ProlongedQTsyndrome

Answer 9

575. (C)Volatile anesthetics, particularly halothane, can have significant adverse effects on cardiac heart rate and rhythm. Halothane may cause direct depression of the sinoatrial node and has been shown to increase the refractory period of the atrioventricular conduction system. Both bradydysrhythmias and tachydysrhythmias have been reported during inhalation induction of anesthesia with halothane. These include sinus bradycardia, nodal or junctional rhythms, and ventricular dysrhythmias. Whereas cardiac dysrhythmias after inhalation induction with halothane are common in children, they are usually benign and do not represent a disease state. Halothane “sensitizes” the myocardium to catecholamines, particularly in the presence of hypoxia, acute hypercarbia, and acidosis. Under these conditions, ventricular rhythms such as bigeminy, multifocal ventricular ectopic beats, and even ventricular tachycardia may occur (Miller: Anesthesia, ed 6, pp 2373-2374).

Question 10

576. Preterm neonates are at an increased risk for retinopathy of prematurity until what postconceptual age? A. 36 weeks
     B. 38 weeks C. 42 weeks D. 44 weeks E. 60weeks

Answer 10

576. (D)The risk of developing ROP is negligible after 44 weeks postconceptional age. Thus, a preterm neonate born at 36 weeks gestational age remains at risk until after 8 weeks of age. See also explanation to question 572 (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 588-589; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 781-782).

Question 11

577. Reasons for selecting a cuffed endotracheal tube over an uncuffed endotracheal tube include all of the following EXCEPT
     A. Fewer intubations and endotracheal tubes are needed B. Lower gas flows can be used
     C. Less chance for airway fires
     D. Spontaneous breathing is easier
     E. Aspirationofgastriccontentsislesslikely

Answer 11

577. (D)Since cuffed endotracheal tubes are often chosen to be a size smaller (i.e., 0.5 mm) than uncuffed endotracheal tubes, the lumen is narrower and therefore spontaneous breathing is more difficult. Because a smaller endo- tracheal tube can be used with a cuff, fewer intubations are needed to select the correct tube size. Also because of the cuff, less leakage of gas exists from the trachea into the pharynx, allowing administration of lower gas flows with potential cost savings as well as less environmental pollution. The gases are less likely to leak into the pharynx and should decrease the chance of an airway fire if high oxygen or nitrous oxide concentrations are used and cautery is used in the oral cavity. The chance of aspiration of gastric contents should also be less likely (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 334-336, 343-346).

Question 12

578. An otherwise healthy 4-year-old male patient is undergoing elective tonsillectomy. Before induction of general anes- thesia, the patient is breathing at a rate of 20 breaths/min. An inhalation induction is begun with sevoflurane, nitrous oxide, and oxygen. Sixty seconds later, the patient is noted to breathe at a rate of 40 breaths/min. This rapid respira- tory rate most likely represents
     A. Hypoxia
     B. Hypercarbia
     C. The excitement stage of anesthesia D. Malignant hyperthermia
     E. Pulmonaryembolism

Answer 12

578. (C)Inhalation agents are respiratory depressants. In general, they increase the respiratory rate and decrease the Vt of respirations and are associated with an increase in Paco2. When inducing a child with an inhalation agent, especially below the MAC level, the respiratory pattern can vary and include breath holding, excessive hyper- ventilation and laryngospasm. Although the stages of inhalation anesthesia were classically described with ether, similar stages are seen with the newer inhalation agents, but because the signs are less pronounced they are rarely described anymore. The classic stages of depth of ether anesthesia include the first stage of anesthesia (analge- sia). Patients in the first stage can respond to verbal stimulation, have an intact lid reflex, have normal respira- tory patterns, and intact airway reflexes and have some analgesia. The second stage of anesthesia (delirium or excitement stage) is associated with unconsciousness, irregular and unpredictable respiratory patterns (including hyperventilation), nonpurposeful muscle movements, and the risk of clinically important reflex activity (e.g., laryngospasm, vomiting, cardiac arrhythmias). The third stage of anesthesia (surgical anesthesia) is associated with a return to more regular periodic respirations and is the level associated with the achievement of MAC. MAC is noted by the absence of movement (in 50% of patients) in response to a surgical incision. As anesthesia is deepened, stage four (respiratory paralysis) is associated with respiratory and cardiovascular arrest. In the case cited in this question, the second stage of anesthesia is demonstrated. Note: Malignant hyperthermia triggered by the sole use of volatile anesthetics (especially halothane) produces an elevation of carbon dioxide levels with tachypnea and tachycardia, but this is rare during the first 20 minutes of an anesthetic (Miller: Anesthesia, ed 6, p 706; Morgan: Clinical Anesthesiology, ed 4, pp 934-935).

Question 13

579. A healthy 1-month-old neonate is anesthetized for an inguinal hernia repair. An inhalation induction with sevoflurane is carried out and the patient is intubated. Before making the surgical incision the systolic blood pressure is noted to be 65 mm Hg and the heart rate is 130 beats/min. The most appropriate intervention for this patient’s blood pressure would be
     A. Administration of ephedrine
     B. Administration of phenylephrine C. 50-mL fluid bolus
     D. Administration of epinephrine E. Noneoftheabove

Answer 13

579. (E)The hemodynamic indices described in this question are normal for healthy 1-month-old neonates (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 89-91; Stoelting: Basics of Anesthesia, ed 5, pp 508-509).

Question 14

580. A 5-year-old boy is anesthetized for elective repair of an umbilical hernia. General anesthesia is induced and main- tained with sevoflurane, nitrous oxide, and oxygen via an anesthesia mask. At the conclusion of the operation, the patient is taken to the recovery room and subsequently discharged to the outpatient ward. Before discharge, the patient’s mother noted that the urine was dark brown in appearance. The most appropriate action at this time would be
     A. Discharge the patient with instructions to return if urine color does not normalize
     B. Discharge the patient in 3 hours if no other signs or symptoms are manifested
     C. Obtain serum creatinine and blood urea nitrogen (BUN) levels and discharge the patient if they are normal
     D. Admit the patient to rule out acute tubular necrosis
     E. Evaluatethepatientformalignanthyperthermia

Answer 14

580. (E)The presence of dark brown urine (i.e., myoglobinemia) may be caused by rhabdomyolysis, a possible sign of malig- nant hyperthermia. More typical signs and symptoms include tachycardia, tachypnea, acidosis, increased sympa- thetic activity, and increased temperature. Accordingly, this patient should be evaluated for malignant hyperthermia. Supportive laboratory tests for malignant hyperthermia include elevated serum creatine phosphokinase (CPK); myo- globin in the serum and urine; increased serum potassium, calcium, and lactate levels; and a metabolic/respiratory acidosis on an arterial blood gas. If the presumed diagnosis is malignant hyperthermia, therapy should be initiated (Barash: Clinical Anesthesia, ed 5, pp 531-532; Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 620-622).

Question 15

581. At what inspiratory pressure should an endotracheal tube leak in an infant? A. 5to15cmH2O
     B. 15to25cmH2O C. 25to35cmH2O D. 35to45cmH2O E. 45to55cmH2O

Answer 15

581. (B)In infants and young children, there should be a small air leak around the endotracheal tube at peak infla- tion pressures of approximately 15 to 25 cm H2O. This test can be performed by slowly increasing the airway pressure and listening with a stethoscope over the larynx to hear when a leak develops. An air leak within this pressure range allows for adequate ventilation and reduces the incidence of postintubation croup (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 335-337).

Question 16

582. A premature newborn delivered at 32 weeks of gestation is brought to the OR for repair of a left-sided congenital diaphragmatic hernia. After awake tracheal intubation, general anesthesia is maintained with halothane, O2, and fen- tanyl. Shortly thereafter, the anesthesiologist notes difficulty with ventilation. The Sao2 subsequently falls to 65% and the heart rate decreases to 50 beats/min. What would be the most appropriate step to take at this time?
     A. Pull the endotracheal tube from the right mainstem bronchus
     B. Ventilate with positive end-expiratory pressure (PEEP) and administer furosemide C. Passanoralgastrictubetodecompressthestomach
     D. Place a chest tube on the right side
     E. Pullouttheendotrachealtubeandreintubatethepatient

Answer 16

582. (D)A congenital diaphragmatic hernia (CDH) is the herniation of abdominal viscera into the chest cavity through a defect in the diaphragm and occurs in approximately 1 in every 4000 live births. Approximately 90% of CDHs occur through a defect in the left side of the diaphragm. Symptoms depend upon the degree of herniation and the amount of respiratory compromise. Some newborns deteriorate in the delivery room whereas others dete- riorate hours later. Immediate intubation of the trachea and decompression of the stomach are needed. Because CDH is associated with hypoplastic lungs, current ventilatory support aims at maintaining a preductal oxygen saturation above 90% using airway pressure below 35 cm H2O and allowing the Paco2 to rise to 60 to 65 mm Hg. If a patient experiences sudden oxygen desaturation during positive-pressure ventilation, a tension pneu- mothorax should be suspected and, if confirmed, a chest tube should be placed on the side contralateral to the congenital diaphragmatic hernia. Despite intensive treatments, about 40% to 50% of these newborns will die in the newborn period (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 593-594; Miller: Anesthesia, ed 6, pp 2396-2397; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 545-550).

Question 17

583. Symptoms of infantile pyloric stenosis occur most frequently between the ages of A. 1 and 2 weeks
     B. 2and6weeks
     C. 6 and 12 weeks D. 3 and 6 months E. 6and12months

Answer 17

583. (B)Infantile pyloric stenosis is one of the most common surgical diseases of neonates and infants. It occurs in about 1 of every 500 live births. Symptoms usually appear between 2 and 6 weeks of age, but they have been diagnosed as early as the first week and as late as the fifth month of life (Miller: Anesthesia, ed 6, p 2395; Motoyama: Smith’s Anes- thesia for Infants and Children, ed 7, pp 690-691; Stoelting: Anesthesia and Co-Existing Disease, ed 5, pp 599-600).

Question 18

584. In a 12-year-old child, the length of an oral endotracheal tube (from the lips to the midtrachea) should be A. 12 cm
     B. 14cm C. 16cm D. 18 cm E. 20cm

Answer 18

584. (D)The depth of insertion of an oral endotracheal tube from the lips to the midtrachea is approximately 7 cm for a 1-kg newborn, 8 cm for a 2-kg, 9 cm for 3-kg and 10 cm for a typical 3.5-kg term newborn. There are many ways to estimate the appropriate depth of insertion of an oral endotracheal tube (in cm) for infants and children.
     One method is age (>3 years): (Age in years)/2 + 12 = tube length
     In this 12-year-old child: 12/2 + 12 = 18 cm.
     Another way is to multiply the tube size by 3. For example when you use a size 4.0 ID endotracheal tube, insert it 12 cm; a size 6.0 endotracheal tube is inserted 18 cm (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 337-338).

Question 19

585. In which of the following conditions would a preoperative evaluation of the heart with echocardiogram be indicated before anesthesia and surgery?
     A. Necrotizing enterocolitis B. Pyloric stenosis
     C. Gastroschisis
     D. Omphalocele
     E. Hypospadias

Answer 19

585. (D)The preanesthetic assessment of neonates with an omphalocele or an imperforate anus should include an assess- ment for other abnormalities including congenital heart disease. Omphalocele is associated with a 20% inci- dence of congenital heart disease, as well as several other congenital anomalies. Conversely, the other conditions in this question are rarely associated with other congenital anomalies. Recall that children with tracheal esopha- geal fistulas also have a 20% incidence of major cardiovascular anomalies (see answer 574) (Miller: Anesthesia, ed 6, pp 2395-2396, 2864).

Question 20

586. An otherwise healthy 14-day-old neonate is transported to the OR well hydrated for surgery for a bowel obstruction. A rapid sequence induction is planned. Compared with the adult dose, the dose of succinylcholine administered to this patient should be
     A. Diminished because of the immature nervous system
     B. The same as the adult dose
     C. Increased because of increased acetylcholine receptors D. Decreased because of decreased acetylcholine receptors E. Increasedbecauseofagreatervolumeofdistribution

Answer 20

586. (E)Neonates and infants (

Question 21

587. The most common cause of neonatal bradycardia (heart rate less than 100 beats/min) is A. Congenital heart disease
     B. Maternal drug intoxication (narcotics, alcohol, magnesium, barbiturates, digitoxin) C. Fever
     D. Postpartum cold stress
     E. Hypoxemia

Answer 21

587. (E)Heart rates less than 100 beats/min are poorly tolerated in the neonate because of the reduced cardiac output and poor tissue perfusion that develops. Congenital heart disease, such as congenital heart block or congenital heart failure, is rare and can be diagnosed by neonatal electrocardiogram and echocardiogram. Maternal medica- tions during labor and delivery rarely cause bradycardia, however, fetal distress as a result of hypoxia may. Fever tends to cause tachycardia. Cold stress of the neonate may lead to hypoxemia, which will promote persistence of the fetal circulation, which is why a neutral thermal environment to minimize heat loss is important. However, the most common cause of neonatal bradycardia in the delivery room is respiratory failure resulting in hypoxia and acidosis. In the operating room, bradycardia results from hypoxia, vagal stimulation and the depressant effects of anesthetic agents (e.g., halothane), which can lead to cardiac arrest (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 1128-1131).

Question 22

588. A 10-week-old infant born at 31 weeks of gestation is anesthetized for repair of an inguinal hernia. General anesthesia is induced by mask with sevoflurane, an endotracheal tube is placed, and anesthesia is maintained with isoflurane, nitrous oxide, and oxygen. At the end of the procedure, the endotracheal tube is removed and the patient is trans- ported to the recovery room. What is the best postoperative pain management for this patient?
     A. Ilioinguinal-iliohypogastric nerve block and discharge home with instructions to parents
     B. Caudal block with 0.25% bupivacaine, 1 mL/kg, and admit to a pediatric ward for overnight observation C. Caudal block with 0.25% bupivacaine, 2 mL/kg, and admit to a pediatric ward for overnight observation D. Oral pain medication and discharge home with instructions to the parent
     E. Fentanyl,1mLIV,andadmittoapediatricwardforovernightobservation

Answer 22

588. (B)Apnea spells are defined as cessation of breathing for at least 20 seconds and are often accompanied by bradycardia and/or cyanosis. Infants (especially former premature newborns) younger than 60 weeks postconceptual age are at risk for apnea after general anesthesia. These patients should be admitted to the hospital and have at least 12 apnea-free hours of monitoring before discharge. This child was born at 31 weeks estimated gestational age and is now 10 weeks old or is 41 weeks postconceptual age and needs to be admitted. Of the postoperative analgesia plans listed with overnight observation, answer B is the most appropriate. Answers C and E include analgesic doses that are too high (Barash: Clinical Anesthesia, ed 5, pp 1192-1193; Miller: Anesthesia, ed 6, pp 1732-1736, 2397-2399).

Question 23

589. A 6-year-old, 20-kg girl develops pulseless ventricular tachycardia after induction of anesthesia with halothane, nitrous oxide, and oxygen for a tonsillectomy. The anesthesiologist intubates the child, administers 100% oxygen, and starts chest compressions. When the defibrillator quickly arrives in the OR the defibrillator should be charged to what energy level for the initial shock?
     A. 20 joules (J) B. 40 joules (J) C. 60 joules (J) D. 80 joules (J) E. 120joules(J)

Answer 23

589. (B)The treatment for documented ventricular fibrillation or pulseless ventricular tachycardia is electrical defibril- lation as soon as possible. Cardiopulmonary resuscitation is performed until the defibrillator arrives, then defi- brillation is attempted. With manual defibrillators (monophasic or biphasic) the initial dose should be 2 J/kg, increasing to 4 J/kg for subsequent shocks. In this 20-kg child the initial dose is 20 × 2 J/kg = 40 J. Automated external defibrillators (AEDs) can be safely used in children 1 to 8 years of age. If using an AED, it is best to use one with a pediatric attenuator system, which decreases the delivered energy to doses appropriate for children (2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 112, pp IV 172-IV 175).

Question 24

590. The spinal cord of newborns extends to the A. L1 vertebra
     B. L2 vertebra C. L3 vertebra D. L5 vertebra E. S1vertebra

Answer 24

590. (C)The position of the inferior end of the spinal cord in relation to the vertebral column and meninges at various stages of development: A, Eight weeks; B, 24 weeks; C, newborn; D, 8-year-old child and adult. The spinal cord of newborns can extend as far down as L3. Therefore, lumbar puncture should be performed in these patients no higher than the L4-L5 interspace (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 465-468).

Question 25

591. The most common initial symptom of esophageal atresia (EA) and tracheoesophageal fistula (TEF) is A. Respiratory distress at delivery (e.g., retractions, tachypnea)
     B. Pneumonia
     C. Hypoxia
     D. Regurgitation during feeding E. Projectilevomiting

Answer 25

591. (D)Esophageal atresia (EA) and TEF are frequently suspected soon after birth when excessive oral secretions, drooling, or coughing are noted and an oral suction catheter cannot be passed into the stomach. Because passage of an oral gastric tube is not routine in many centers, the first manifestation of esophageal atresia occurs when the newborn has trouble breathing (e.g., coughing) and regurgitates with the first feeding. After the diagnosis is made, these patients should be placed in the head-up position and the blind upper pouch of the esophagus should be decompressed with a suction tube immediately to reduce pulmonary aspiration of secretions. Other abnormalities associated with EA and TEF include VACTERL (Vertebral abnormalities, imperforate Anus, Congenital heart disease, Tracheoesophageal fistula, Renal abnormalities, Limb abnor- malities) (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 595-596; Miller: Anesthesia, ed 6, p 2396).

Question 26

592. A 4-kg, 3-hour-old newborn with macrosomia and large fontanelles is scheduled for surgical repair of an omphalocele. Physical examination reveals macroglossia but no other anomalies are found. Which of the following is likely to occur in this patient? A. Hypokalemia
     B. Hyperkalemia
     C. Metabolic acidosis D. Hypoxemia
     E. Hypoglycemia

Answer 26

592. (E)Omphalocele is the external herniation of abdominal viscera through the base of the umbilical cord. It occurs in about 1 of 5000 cases. Thirty percent of these newborns will die in the neonatal period, primarily from cardiac defects or prematurity. Some of these newborns with omphalocele have a syndrome called Beckwith-Wiede- mann syndrome. This syndrome is characterized by omphalocele, organomegaly, macrosomia, large fontanelles, macroglossia, polycythemia, and hypoglycemia. These patients may be very difficult to intubate because of their significant macroglossia (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, p 596; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 1215).

Question 27

593. Which of the following is the LEAST appropriate technique for induction of general anesthesia in a newborn for surgical repair of TEF?
     A. Awake tracheal intubation
     B. Inhalation induction with spontaneous ventilation and tracheal intubation
     C. Inhalation induction using positive-pressure bag and mask ventilation and tracheal intubation D. Rapid IV induction and tracheal intubation
     E. Intramuscularinductionwithhigh-doseketamineandtrachealintubation

Answer 27

593. (C)Anesthesia for patients with EA and TEF can be safely induced with either an intravenous or volatile anesthetic. However, positive-pressure bag and mask ventilation will force gas into the stomach, potentially making ventila- tion of the lungs more difficult and should be avoided. A frequently used technique to facilitate correct place- ment of the endotracheal tube is to advance the tube into a bronchus. While listening over the stomach, slowly withdraw the tube until breath sounds are heard over the stomach. Advance the tube until these sounds become diminished (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, p 596; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 551-552).

Question 28

594. Each of the following statements concerning side effects of succinylcholine when used to paralyze neonates is true EXCEPT
     A. It seldom causes muscle fasciculation
     B. It can cause bradycardia
     C. Dysrhythmias frequently occur following intramuscular injections D. It can cause myoglobinuria
     E. Itcancausehyperkalemia

Answer 28

594. (C)Unlike adults, neonates and infants seldom have muscle fasciculations with succinylcholine. The most frequently encountered side effect associated with succinylcholine in neonates and infants is bradycardia, especially when succinylcholine is given intravenously. The incidence of bradydysrhythmias is significantly decreased when the succinylcholine is administered intramuscularly. Other side effects include rhabdomyolysis, myoglobinuria, hyperkalemia, and malignant hyperthermia (Miller: Anesthesia, ed 6, pp 2378-2379; Motoyama: Smith’s Anesthe- sia for Infants and Children, ed 7, pp 219-220).

Question 29

595. The predicted blood volume in a 4-kg neonate is A. 240 mL
     B. 280 mL C. 340 mL D. 400 mL E. 440mL

Answer 29

595. (C)The estimated blood volume (EBV) of healthy full-term neonates is approximately 80 to 90 mL/kg. For this 4-kg neonate the volume is 320 to 360 mL. Premature newborns have an EBV of 90 to 100 mL/kg, whereas the 3- to 12-month-old infant has an EBV of 75 to 80 mL/kg (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 367; Stoelting: Basics of Anesthesia, ed 5, p 510).

Question 30

596. The pulmonary vascular resistance in newborns decreases to that of adults by age A. 1 day
     B. 1 week C. 2 months D. 2 years E. 5years

Answer 30

596. (C)In the fetus, pulmonary vascular resistance is extremely high. Most of the right ventricular output in utero bypasses the lungs and flows into the descending aorta through the ductus arteriosus. With the onset of ventila- tion at birth the pulmonary vascular resistance suddenly decreases, enabling blood to flow more easily through the lungs. Pulmonary vascular resistance continues to decrease after birth reaching adult levels by 2 to 3 months of life. This is when children with left-to-right cardiac shunts increase their shunts making symptoms of conges- tive heart failure (CHF) more apparent. The increase in Pao2 not only acts as a pulmonary artery vasodilator (along with the lowering of the Paco2) but also acts as a vasoconstrictor to the ductus arteriosus (thus further assisting the change from the fetal to the adult circulation) (Miller: Anesthesia, ed 6, pp 2833-2834; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 73).

Question 31

597. A 10-month-old infant is undergoing elective repair of a left testicular hydrocele under general anesthesia with isoflu- rane, nitrous oxide, oxygen, and fentanyl. All of following are effective and reasonable means of preventing hypother- mia in this patient EXCEPT
     A. Placement of an infrared heater over the operating table and prewarming the OR
     B. Covering the OR table with a heating blanket
     C. Wrapping the extremities with sheet wadding and covering the head with a cloth cap D. Ventilating the patient with a Mapleson D circuit at low gas flows (e.g., 50 mL/kg/min) E. Warmingandhumidifyingtheinspiredanestheticgases

Answer 31

597. (D)A comprehensive understanding of thermoregulation and meticulous attention to details during the anesthetic care of infants are necessary to minimize intraoperative heat loss. In anesthetized infants, the heat loss occurs through the transfer of heat from the patient to the environment in one of four ways: radiation, conduction, convection and evaporation. For this reason, placement of an infrared heater over the OR table and prewarm- ing the OR atmosphere are the most effective means of preventing hypothermia in these patients. Covering the OR table with a heating blanket; ventilating the patient with warm, humidified anesthetic gases; wrapping the extremities of the patient with sheet wadding; and covering the patient’s head with a cloth or plastic cap can also reduce heat loss and prevent hypothermia. Convective forced-air warmers can help prevent a decrease in body temperature and also have been effective in rewarming hypothermic patients. A Mapleson D breathing circuit is not a circle system and does not preserve heat or moisture. To prevent rebreathing of expired gases spontaneous breathing flow rates need to be 2 to 3 times the minute ventilation and for controlled ventilation fresh gas flows need to be greater than 90 mL/kg/min. Low flows such as 50 mL/kg/min with Mapleson circuits are inadequate and will result in respiratory acidosis (Miller: Anesthesia, ed 6, pp 1584-1586; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 170-173).

Question 32

598. Central postoperative depression of ventilation in a full-term neonate is most likely to occur after surgery for which of the following?
     A. Gastroschisis
     B. Omphalocele
     C. Tracheoesophageal fistula D. Diaphragmatic hernia
     E. Pyloricstenosis

Answer 32

598. (E)Although all of the conditions can produce ventilatory depression in the postoperative period, only pyloric ste- nosis produces central nervous system (CNS) depression of respiration. Patients with pyloric stenosis have protracted vomiting that leads to dehydration, hypokalemia, hyponatremia, hypochloremia, and metabolic alkalosis. Postoperative ventilatory depression frequently occurs in infants with pyloric stenosis, thought to be related to cerebrospinal fluid (CSF) alkalosis that is worsened by intraoperative hyperventilation of the lungs. Thus, these patients should be fully awake with a normal rate and pattern of respiration before extubation is considered. This is one reason infants with pyloric stenosis should be stabilized and hydrated before coming to the OR. The other conditions listed can lead to mechanical, not central, causes of respi- ratory difficulty in the postoperative period (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 599-600).

Question 33

599. A premature male neonate born at 32 weeks of gestation is scheduled to undergo emergency repair of a left-sided diaphrag- matic hernia. Which of the following vessels could be cannulated for preductal arterial blood sampling?
     A. Femoral artery
     B. Umbilical artery
     C. Dorsalis pedis artery D. Right radial artery E. Leftradialartery

Answer 33

599. (D)Newborns with diaphragmatic hernia have significant respiratory difficulty. In addition to their hypoplastic lungs, persistent pulmonary hypertension is present, producing right-to-left shunting through the patent ductus arteriosus. To more appropriately administer the anesthetic, a preductal (ductus arteriosus) artery should be cannulated to monitor arterial blood gases and blood pressure. The right radial or temporal arteries arise from vessels that originate from the aorta proximal to the ductus arteriosus. The oxygen saturation monitors should be placed on the right arm as well (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 593-594).

Question 34

600. In which of the following patients would the minimum alveolar concentration (MAC) for halothane or isoflurane be the greatest?
     A. A premature infant 30 weeks postconceptual age B. Full-term neonate
     C. 3-month-old infant
     D. 19-year-old male bodybuilder
     E. 35-year-oldwomanwithhyperthyroidism

Answer 34

600. (C)The MAC for halothane and isoflurane is greatest at age 3 months. The MAC is lower in preterm neonates com- pared with term neonates. The low MAC in the newborns may be related to the immaturity of the CNS and/orrelated to the elevated levels of progesterone and β-endorphins. The increase in MAC in the first few weeks after birth seems to be related to the falling progesterone levels. After age 3 months, the MAC of these volatile anes- thetics steadily declines with aging except for a slight increase at puberty. For reasons that are unclear, the MAC for sevoflurane is similar in neonates and infants younger than 6 months (3.2%). The MAC of sevoflurane then decreases with age, 6 months to 12 years (2.5%) (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, p 584; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 211).

Question 35

601. A 40-kg, 10-year-old child sustains a thermal injury to his legs, buttocks, and back. The estimated area involved is 50%. How much fluid should be administered during the first 24 hours?
     A. 2.5 L
     B. 4.0L
     C. 5.5L D. 8.0 L E. 10.0L

Answer 35

601. (D)
     Intravascular fluid-volume deficits in patients with burn injuries are roughly proportional to the extent and depth of the burn. For reasons that are unclear, the vascular compartment, particularly in the area of the burn, becomes hyperpermeable to plasma proteins, such as fibrinogen and albumin. These proteins subsequently exert an osmotic pressure gradient that favors the translocation of intravascular fluid into the extravascular third space. Therefore, during this period (approximately first 24 hours), administration of colloid solutions would be of no benefit to the patient and might exacerbate third-space translocation of fluids. As a rule of thumb, an estimated 4 mL/kg of fluid is lost for each percent of body surface area burned. Thus, in this case: 4 × 40 (kg) × 50 (%) = 8000 mL. Approximately two thirds of this fluid should be replaced with isotonic crystalloid solutions during the first 8 hours after the injury. This estimate is modified clinically by the patient’s clinical response as noted by the vital signs and urine output (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 630-635).

Question 36

602. An otherwise healthy 3-month-old black female infant with a hemoglobin of 19 mg/dL at birth presents for elective repair of an inguinal hernia. Her preoperative hemoglobin is 10 mg/dL. Her father has a history of polycystic kidney disease. The most likely explanation for this patient’s anemia is
     A. Sickle cell trait
     B. Sickle-cell anemia
     C. Iron deficiency
     D. Undiagnosed polycystic kidney disease E. Itisanormalfinding

Answer 36

602. (E)The most likely explanation for the “falling” hemoglobin level in this patient is that this is a normal physiologic finding. At birth, a full-term infant has a hemoglobin level of approximately 15 to 20 g/dL. A physiologic ane- mia occurs by age 2 to 3 months, resulting in hemoglobin concentrations of approximately 10 to 12 g/dL. After 3 months, there is a progressive increase in hemoglobin concentration, which reaches levels similar to that of adults by age 6 to 9 months (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, p 583; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 397).

Question 37

603. The anesthesiologist is called to the emergency room by the pediatrician to help manage a 3-year-old boy with a high fever and upper airway obstruction. His mother states that earlier that afternoon, he complained of a sore throat and hoarseness. The patient is sitting erect and leaning forward, has inspiratory stridor, tachypnea, and sternal retractions, and is drooling. Which of the following is the most appropriate management of airway obstruction in this patient? A. Aerosolized racemic epinephrine
     B. Awaketrachealintubationintheemergencyroom
     C. Transfer to the OR and awake tracheal intubation
     D. Transfer to the OR, inhalation induction, and tracheal intubation
     E. TransfertotheOR,IVinduction,paralysiswithsuccinylcholine,andtrachealintubation

Answer 37

603. (D)This history is consistent with an acute life-threatening cause of upper airway obstruction called epiglottitis (or more appropriately supraglottitis because other supraglottic structures are involved as well). In the past it was caused most often by Haemophilus influenzae. With widespread immunization against H. influenzae this condi- tion has become much less frequent and the primary causes now are Neisseria meningitidis, group A Streptococ- cus, and Candida albicans. This condition is a medical emergency that can progress to respiratory obstruction in just a few hours. When suspected, the anesthesiologist and otolaryngologist should be notified and the child immediately transferred to the OR (with the parent if appropriate) before complete upper airway obstruction ensues. In the OR, anesthesia should be induced with halothane or sevoflurane and oxygen with the child in a sitting position. Halothane or sevoflurane are less likely to induce laryngospasm than isoflurane, or desflurane. IV access should be established as soon as the child is deeply anesthetized. Atropine should be administered to block vagally mediated bradycardia induced by direct laryngoscopy. Muscle relaxants are contraindicated because they can cause complete obstruction of the upper airway in these patients. The trachea should be intu- bated under direct laryngoscopy when the depth of anesthesia is sufficient to blunt laryngeal reflexes (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 614-616; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 810-812).

Question 38

604. A 2-year-old child with cerebral palsy and known severe gastroesophageal reflux (with frequent nightly aspiration) is scheduled to undergo iliopsoas release under general anesthesia. Which of the following would be the most appropri- ate technique for inducing general anesthesia in this patient?
     A. Inhalation induction with sevoflurane followed by mask anesthesia with cricoid pressure
     B. Inhalation induction with sevoflurane followed by tracheal intubation
     C. IV induction with propofol followed by laryngeal mask airway
     D. IV induction with propofol followed by tracheal intubation
     E. Rapid-sequenceinductionwiththiopentalandsuccinylcholinefollowedbytrachealintubation

Answer 38

604. (E)Cerebral palsy is a CNS symptom complex. The most common clinical manifestation is skeletal muscle spastic- ity. It is usually classified according to the extremity affected (e.g., monoplegia, hemiplegia, diplegia, or quad- riplegia) and the characteristics of the neurologic dysfunction (spastic, hypotonic, dystonic, athetotic). Other manifestations include cerebellar ataxia, seizure disorders, varying degrees of mental retardation, and speech deficits. Gastroesophageal reflux is also common. For this reason, the preferred induction of general anesthesia in these patients should include a rapid-sequence IV induction followed by immediate tracheal intubation. Even though these patients have skeletal muscle spasticity, there have been no reports of succinylcholine-induced hyperkalemia. The response to nondepolarizing muscle relaxants is normal (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, p 603).

Question 39

605. A 7-week-old male infant is admitted to the pediatric intensive care unit (ICU) with a bowel obstruction. His labora- tory values are sodium 120 mEq/L, chloride 85 mEq/L, glucose 85 mg/dL, and potassium 2.0 mEq/L. Respiratory rate is 20 breaths/min, and according to the patient’s mother, urine output has been 0 for the last 4 hours. The most appropriate fluid for resuscitation of this patient would be
     A. D5W
     B. D5W with 0.45 sodium chloride and 20 mEq/L potassium chloride C. 0.45% sodium chloride
     D. 0.9% sodium chloride with 30 mEq/L potassium chloride
     E. 0.9%sodiumchloride

Answer 39

605. (E)The symptoms described in this patient are consistent with severe dehydration. Thus, the vascular volume should be expanded initially with an isotonic saline solution or a colloid solution until the patient voids. When the urine output increases, potassium can be added to the IV fluids. Although glucose administration for long procedures may prevent hypoglycemia, D5W alone or with a crystalloid solution should not be used to replace fluid deficits (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 119-121).

Question 40

606. An 8-hour-old, 1600-g neonate, 30 weeks postgestational age, is noted in the ICU to begin making twitching move- ments. Blood pressure is 45 mm Hg systolic, blood glucose 50 mg/dL, and urine output 10 mL/hr. The O2 saturation on pulse oximeter is 88%. The most appropriate course of action to take at this point would be
     A. Administer calcium gluconate 250 mg (2.5 mL of 10% solution)
     B. Glucose 10 mg IV over 5 minutes (2 mL of D5W) C. Hyperventilate with 100% O2
     D. Administer a 20-mL bolus of 5% albumin
     E. Beginadopamineinfusion

Answer 40

606. (A)Preterm infants have very limited calcium reserves and are very susceptible to hypocalcemia. Hypocalcemia (serum ionized calcium level less than 1.5 mEq/L) manifests itself in a number of nonspecific ways, including irritability, twitching, hypotension, and seizure. A dose of 100 to 200 mg/kg of calcium gluconate administered over 2 to 3 minutes will be appropriate and repeated every 6 to 8 hours until the calcium levels stabilize. Some of the signs of hypoglycemia are similar to those of hypocalcemia and include seizure, irritability, hypotension, and sometimes bradycardia and apnea. In the patient described in this question, the glucose has already been measured at 50 mg/dL, which is acceptable for a preterm infant. An O2 saturation of 88% is also acceptable because the patient is at risk for retinopathy of prematurity (i.e., younger than 44 weeks postconceptual age). Hyperventilation would cause alkalosis, which would decrease the unbound fraction of calcium and make the patient more susceptible to seizures. Furthermore, calcium binds to albumin, which would further reduce the free calcium. Because the urine output is more than adequate, it is unlikely that the patient needs a fluid bolus to correct hypotension (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 590-592).

Question 41

607. An Eutectic Mixture of the Local Anesthetics (EMLA) cream is a mixture of which local anesthetics? A. Lidocaine and prilocaine
B. Lidocaine and benzocaine
C. Prilocaine and benzocaine
D. Mepivacaine and lidocaine
E. Prilocaine,benzocaine,andlidocaine

Answer 41

607. (A)An Eutectic Mixture of the Local Anesthetics (EMLA) cream is lidocaine (2.5%) and prilocaine (2.5%). When the 5% EMLA cream is applied to dry intact skin and covered with an occlusive dressing for at least 1 hour, topical anesthesia to a depth of 5 mm is obtained. Eutectic mixture of the local anesthetics (EMLA) appears to be relatively safe in neonates, and methemoglobinemia is exceeding rare (Miller: Anesthesia ed 6, pp 589-590; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 500).

Question 42

608. Advantages of catheterization of the umbilical artery versus the umbilical vein in a newborn include all of the following EXCEPT
     A. It allows assessment of oxygenation
     B. Hepatic damage from hypertonic infusion is avoided C. It permits assessment of systemic blood pressure
     D. It is easier to cannulate
     E. Therearetwovesselstochoosefrom

Answer 42

608. (D)Although the umbilical vein (UV) is larger and easier to cannulate than the umbilical artery (UA), the UV will not allow for adequate assessment of arterial blood gases or systemic blood pressure. Additionally, administra- tion of drugs or hypertonic solutions into the umbilical vein may be hazardous, because the catheter can become wedged in a portal radicle and may lead to hepatic necrosis or portal vein thrombosis. To prevent this, the umbilical vein catheter tip is advanced only 2 to 3 cm into the umbilical vein (to a point where blood can first be aspirated). Careful placement of an umbilical artery catheter is equally important. The tip of the umbilical artery catheter should be placed just above the bifurcation of the aorta and below the celiac, renal, and mesen- teric arteries (i.e., ideally between L3 and L4). Dislocation may be hazardous because improper placement may be associated with thrombosis or embolism in these major vessels. As there are two arteries and only one vein, difficulty with one artery gives another artery to use (Miller: Anesthesia, ed 6, pp 2356-2357, 2843-2844).

Question 43

609. The true statement concerning thermoregulation in neonates is which of the following?
     A. A significant proportion of their heat loss can be accounted for by their small surface area-to-weight ratio B. They compensate for hypothermia by shivering
     C. The principal method of heat production is metabolism of brown fat
     D. Heat loss through conduction can be reduced by humidification of inspired gases
     E. Heatlossbyconvectionisreducedwiththeuseofawarmingblanket

Answer 43

609. (C)Because of the large surface-area-to-weight ratio, the thin layer of insulating subcutaneous fat, and the limited ability to compensate for cold stress, neonates and infants are at greater risk for intraoperative hypothermia than adults. Infants younger than 3 months do not produce heat by shivering; their principle method of thermo- genesis is metabolism of brown fat. Heat loss can occur by radiation, conduction, convection and evaporation. Heat loss through evaporation (not conduction) can be reduced by humidification of inspired gases. Heat loss by conduction (not convection) is reduced with the use of a warming blanket (Miller: Anesthesia, ed 6, pp 1576, 2371).

Question 44

610. Normal values for a healthy 6-month-old, 7-kg infant include A. Hemoglobin 17 g/dL
     B. Heart rate 90 beats/min
     C. Respiratory rate 20 breaths/min
     D. O2 consumption at rest 35 mL/min E. Systolicbloodpressureof70

Answer 44

610. (D)In a 6-month-old infant, a normal hemoglobin value is approximately 11 to 12 gm/dL. The normal heart rate is about 120 beats/min, systolic blood pressure is 90 to 95, and the respiratory rate is about 24 to 30 breaths/min. O2 consumption in infants is 5 mL/kg/min (5 mL/kg × 7 kg = 35 mL/min), approximately two times that of adults (Stoelting: Basics of Anesthesia, ed 5, pp 508-510).

Question 45

611. A 5-year-old child undergoing strabismus surgery under general anesthesia suddenly develops sinus bradycardia and inter- mittent ventricular escape beats, but is hemodynamically stable. Which therapy is appropriate for treating this arrhythmia? A. Tell the surgeon to stop pulling on the eye muscle
     B. Tell the surgeon to do a retrobulbar block
     C. Change from halothane to sevoflurane
     D. Decrease the depth of the volatile anesthetic E. Administeratropine

Answer 45

611. (A)The oculocardiac reflex (OCR) is commonly defined as a 10% to 20% decrease in heart rate that is sustained for more than 5 seconds. It can be induced by traction on extraocular muscles, pressure on the eye, orbital hematoma, ocular trauma, or eye pain. It is commonly seen with strabismus operations and may produce a wide variety of cardiac arrhythmias, including sinus bradycardia, nodal bradycardia, ectopic beats, ventricular fibrilla- tion, and, rarely, asystole (1 in 2200 strabismus operations). The initial treatment of this is to stop the stimulus (i.e., tell the surgeon to stop what he or she is doing). This reflex quickly responds and future similar stimulation typically gives less of a response. In many cases no further treatment is necessary. Other manipulations that can be done include increasing the depth of general anesthesia, changing from halothane to sevoflurane (which has a lower incidence of the reflex), and reassessing the adequacy of ventilation (as hypercarbia decreases the thresh- old to elicit the OCR). A retrobulbar block with prevent the reflex. Infiltrating lidocaine locally into the recti muscles may be effective in preventing and treating the OCR. Atropine or glycopyrrolate can be administered if the arrhythmia persists. Some advocate the prophylactic use of atropine or glycopyrrolate during strabismus surgery, especially in children (Miller: Anesthesia, ed 6, pp 2535-2536; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 778-780).

Question 46

612. Which of the following respiratory indices is increased in neonates compared with adults? A. Tidal volume (Vt) (mL/kg)
     B. pH
     C. Alveolar ventilation (mL/kg/min)
     D. Functional residual capacity (mL/kg) E. Paco2

Answer 46

612. (C)There is no difference in Vt between neonates and adults. Neonates have a high O2 consumption (about twice the adult). To compensate for the increased oxygen demand alveolar ventilation is increased (also about twice the adult). The increase in alveolar ventilation explains the slightly lower Paco2. Of note, however, is that the pH is slightly lower as well. The reduced functional residual capacity with the increased O2 consumption places the neonate at an increased risk for hypoxia during general anesthesia if there is any difficulty with ventilation (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 582-583; Stoelting: Basics of Anesthesia, ed 5, pp 508-509).

Question 47

613. A 14-year-old girl with neurofibromatosis is anesthetized for resection of an acoustic neuroma. Each of the following may potentially complicate the anesthetic management of this patient EXCEPT
     A. Presence of a pheochromocytoma
     B. Upper airway obstruction from a laryngeal neurofibroma
     C. Intracranial hypertension
     D. Increased risk for malignant hyperthermia
     E. Abnormalresponsetoneuromuscularblockingagents

Answer 47

613. (D)Neurofibromatosis (von Recklinghausen’s disease) is an autosomal dominant genetic disorder characterized by multiple neurofibromas involving the skin and peripheral and central nervous systems. The clinical features of this disease are diverse and always progress with time. The anesthetic management of patients with neurofibro- matosis can be complicated by the associated clinical manifestations of this disease. For example, a pheochromo- cytoma may be present in approximately 1% of patients. If this is unrecognized, severe hypertension can occur during anesthesia. Intracranial tumors occur in 5% to 10% of patients and signs and symptoms of intracranial hypertension may develop. If intracranial pressure is elevated, efforts to reduce intracranial pressure should be initiated. Finally, airway patency may become compromised by an enlarging laryngeal neurofibroma. Abnor- mal responses to both depolarizing neuromuscular blocking agents (sensitive or resistant) and nondepolarizing neuromuscular blocking agents (sensitive) have been described. There is no evidence that these patients are at increased risk for malignant hyperthermia (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 1221; Hines: Stoelting’s: Anesthesia and Co-Existing Disease, ed 5, pp 226-227).

Question 48

614. Retinopathy of prematurity
     A. Occurs only after exposure to high concentrations of O2 for 12 or more hours
     B. Cannot occur in patients who have never received supplemental O2
     C. Is caused by obliteration of immature retinal arteries
     D. Is most commonly seen in newborns younger than 44 weeks postconceptual age
     E. Ismorecommoninnewbornswhenanesthesiaisadministeredfornon-ophthalmologicprocedures

Answer 48

614. (D)Retinopathy of prematurity (ROP) is an abnormal proliferation of immature retinal vessels, which usually occurs after exposure to hyperoxia. The most significant risk factor for ROP is prematurity and is inversely related to birth weight. More than 50% of premature infants who weigh 750 to 1000 g and survive develop ROP; fortunately, many of these infants have spontaneous regression of the retinal changes. The most recog- nized risk of ROP in premature infants is elevated oxygen concentrations (i.e., Pao2 > 80 to 90 mm Hg for prolonged periods) in neonates younger than 44 weeks postconceptual age. It is possible to develop ROP with exposures as short as 1 to 2 hours to a Pao2 of 150 mm Hg. However, ROP has also occurred in patients who have never received supplemental oxygen and in some newborns who have cyanotic heart disease, making the etiology a bit unclear. Other associated factors include hypoxia, hypercarbia, hypocarbia, sepsis, and apnea. Retinopathy of prematurity (ROP) is clearly a multifactorial disease that cannot be explained simply by expo- sure to high concentrations of oxygen. At one time, the administration of anesthesia for non-ophthalmologic procedures was believed to cause an increase incidence of ROP, but further studies have revealed no increased incidence. When administering anesthesia to infants younger than 44 weeks postconceptual age, the goal of oxygen therapy is to maintain a Pao2 of 60 to 90 mm Hg (oxygen saturation of 90% to 95%) (Miller: Anesthesia, ed 6, pp 2534-3535; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 781-782).

Question 49

615. The most reliable method of determining mild dehydration in a child is by the observation of A. Dryness of mucous membrane
B. Skin turgor
C. Urine output
D. Fontanelles
E. Bloodpressure

Answer 49

615. (C)The amount of dehydration that children have can be assessed by a variety of observations. For mild dehydra- tion (5% weight loss) the only abnormal finding of the listed answers is urine output which would be less than 2 mL/kg/hr. With moderate dehydration (10% weight loss) mucous membranes would be dry, skin turgor would be decreased, urine output would be less than 1mL/kg/hr, the anterior fontanel would be depressed andblood pressure would be normal to low. With severe dehydration (15% weight loss) mucous membranes would be very dry, skin turgor would be greatly decreased, urine output would be less than 0.5 mL/kg/hr, the anterior fontanel would be markedly depressed and blood pressure would be reduced and orthostatic (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 119-120).

Question 50

616. Postoperative bleeding following tonsillectomy occurs most commonly A. By the first 6 hours
     B. 6-24 hours postop
     C. On third postoperative day D. On seventh postoperative day E. Ontenthpostoperativeday

Answer 50

616. (A)Postoperative bleeding after a tonsillectomy occurs in 0.1% to 8% of cases. The bleeding is defined as primary if it occurs within 24 hours and secondary if more than 24 hours after surgery. Most fatal cases are due to primary bleeding. Because of the risk of significant bleeding most often occurs within the first 6 hours after the surgery (75% of bleeding cases), most units keep patients for at least 6 to 8 hours after the surgery is completed. Sixty- seven percent of bleeding occurs in the tonsillar fossa alone, 27% in the nasopharynx alone, and the rest in both the tonsillar fossa and the nasopharynx (Barash: Clinical Anesthesia, ed 5, pp 998-1001; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 798-799).

Question 51

617. A 9 year old undergoing sinus surgery is treated with an unmeasured amount of 0.5% phenylephrine by the surgeon and the patient develops a blood pressure of 250/150. The most appropriate treatment for this would be
A. Administer verapamil
B. Administer esmolol
C. Administer labetalol
D. Administer atropine
E. Administerphentolamine

Answer 51

617. (E)Ear, nose and throat surgeons often use vasoconstrictors (e.g., phenylephrine, cocaine or oxymetazoline) to control bleeding in pharyngeal and nasal surgery. For adults, the initial dose of phenylephrine is up to 0.5 mg (4 drops of a 0.25% solution). For children, the initial dose is up to 0.20 μg/kg. When excessive doses are used, severe hypertension and cardiovascular decompensation may develop due to the marked increase in peripheral vascular resistance. This also shifts blood from the peripheral site into the pulmonary vasculature (which is less sensitive to vasoconstrictors) and increases left ventricular filling pressure. In this case, the use of labetalol and deepening the anesthesia has been associated with severe pulmonary edema, cardiac arrest, and death. If labetalol or a β blocker (e.g., esmolol) is used and CHF develops, consider using high dose glucagon (5-10 mg) to counteract the loss of cardiac contractility. This may also occur with the use of calcium channel blockers. Baroreceptor-induced bradycardia may not occur in the pediatric patient who has been pretreated with atropine or glycopyrrolate during the anesthetic. The hypertension may be short lived and deepening the inhalation anesthetic may help; however, treatment of severe hypertension is best with direct vasodilators or α adrenergic receptor antagonists (Miller: Anesthesia, ed 6, pp 2547-2548; Groudine SB et al. New York State Guidelines on the topical use of phenylephrine in the operating room. Anesthesiology, 92:859-864, 2000).

Question 52

618. A 6-kg, 3-month-old male infant undergoes a left inguinal herniorrhaphy with a spinal anesthetic. How long would 0.5 mL of a 0.5% bupivacaine solution be expected to last?
     A. Less than 30 minutes
     B. 30 to 60 minutes
     C. 60 to 90 minutes
     D. 90 minutes to 2 hours E. Cannotbepredicted

Answer 52

618. (C)Tetracaine and bupivacaine are the most commonly used drugs for spinal anesthesia in infants. For infants who weigh 5 to 15 kg, a dose of 0.4 mg/kg of 1% tetracaine will last about 80 minutes, 0.4 mg/kg of 0.5% bupivacaine would last about 70 to 80 minutes. For infants less than 5 kg, the dose is larger, i.e., 0.5 mg/kg for tetracaine and 0.5 mg/kg for bupivacaine, and the duration of the anesthetic is about 5 minutes shorter. If epinephrine is added, the duration of a tetracaine spinal anesthetic is about 30% to 50% longer. Epinephrine added to bupivacaine has little effect (Miller: Anesthesia, ed 6, pp 1737-1738).

Question 53

619. In addition to inspiratory stridor, which sign or symptom is consistent with epiglottitis? A. Rapid onset in less than 24 hours
     B. Mild temperature elevation (

Answer 53

619. (A)About 80% of children with inspiratory stridor have laryngotracheobronchitis (croup) and about 5% have epiglottitis (also called acute supraglottitis). All of the answers listed except A, as well as a “barking cough,” refer to signs and symptoms of laryngotracheobronchitis, a viral illness that usually presents in children between 6 months and 6 years of age. Patients with acute epiglottitis (or supraglottitis) are usually 2 to 7 years of age. The onset of signs and symptoms of acute epiglottitis is typically rapid, less than 24-hours. They present with difficulty swallowing, a high fever (often > 39° C), and inspiratory stridor. Other signs and symptoms include drooling, lethargy, cyanosis, tachypnea, neutrophilia, and a propensity to sit up and lean forward (in an attempt to main- tain their airway). Total upper airway obstruction can occur in these children at any time because of the rapid progression of the disease. For this reason, attempts to visualize the epiglottis should not be undertaken until the patient is in the OR and appropriate preparations are completed for direct laryngoscopy and tracheal intubation, and possible emergency tracheostomy. The definitive treatment of acute epiglottitis includes appropriate antibi- otic therapy and a secured airway. Also see explanation to question 603 (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 810-812; Hines: Stoelting’s: Anesthesia and Co-Existing Disease, ed 5, pp 614-617).

Question 54

620. Which technique for resuscitation of a 6-month-old by a lay single rescuer is correct
     A. Mouth-to-mouth or mouth-to-nose ventilation at a rate of 12 to 20 breaths/min with good chest expansion B. Chestcompressionswithtwofingersontheupperhalfofthesternumjustabovetheintermammaryline
     C. Sternalcompressiondepthofnomorethan1⁄2cm
     D. Lay rescuer should check the carotid pulse every minute
     E. Compressiontoventilationratioof5:1

Answer 54

620. (A)The technique for cardiopulmonary resuscitation of infants (younger than 1 year) and children (ages 1 to 8 years) is different from that of adults. Ventilation is begun for adults at a rate of 10 to 12 breaths/min, whereas for children and infants, the rate is 12 to 20 breaths/min. For adults, sternal compressions should be performed with the heel of one hand placed on top of the other hand and compressing the lower half of the sternum 4 to 5 cm (1.5 to 2 inches). For children, sternal compressions should be performed with the heel of one hand compressing the lower half of the sternum 2.5 to 4 cm (1 to 1.5 inches; or about one third to one half the depth of the chest). For infants, sternal compressions should be performed by depressing the lower half of the sternum just below the intermammary line. This is done with either two or three fingers or by encircling the chest withboth hands and depressing the sternum with the thumbs. Sternal compressions are performed to a depth of 1 to 2.5 cm (0.5 to 1 inch; or about one third to one half the depth of the chest). The compression rate is the same for adults, children and infants, approximately 100 compressions/min. Lay rescuers should not check for pulses in infants or children as they often feel a pulse that is not present. When health care providers palpate for pulses, the brachial artery is preferred in the infant and the carotid or femoral is preferred in the child. A universal compression to ventilation ratio of 30:2 is used for (infants, children and adults) by single rescuers. Earlier it was taught to use a 5:1 ratio, but more recent evidence shows 30:2 to be more effective. For newborns however, a ratio of 3:1 (90 compressions and 30 ventilations/minute) is used (2005 American Heart Association Guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation 112: IV15, IV157-IV161, IV 192, 2005).

Question 55

621. All of the following are true statements concerning physiology of newborns compared with that in adults EXCEPT A. Newborns have a greater percentage of total body water compared with adults
     B. Newbornshaveaprolongedeffectwiththiopental
     C. Newborns have a higher glomerular filtration rate than adults
     D. Newborn hearts are relatively non-compliant compared with adults
     E. NewborndiaphragmshavealowerproportionoftypeImusclefibers(i.e.,fatigueresistant,highlyoxidativefibers)

Answer 55

621. (C)Body composition changes dramatically during the first year of life. Total body water is about 80% for a term newborn compared with 55% for an adult woman and 60% for an adult man. Drugs that are water soluble (such as many antibiotics) will need to have higher mg/kg dose to achieve the desired blood concentrations. With the corresponding lower fat content of the preterm newborn (

Question 56

622. Which of the following statements concerning the anatomy of the infant airway compared with the adult airway is true?
     A. The larynx is at the C5-C6 level in infants and C6-C7 in adults
     B. The epiglottis is relatively small in infants compared with adults
     C. The glottic opening is more anterior in infants than in adults
     D. The vocal cords are in a more horizontal position within the larynx in infants than in adults
     E. The vocal cords are the narrowest part of the larynx in infants, whereas the cricoid cartilage is the narrowest part
     of the larynx in adults

Answer 56

622. (C)The anatomy of the infant’s airway is different from the adult’s anatomy in several respects. The head and tongue are relatively larger in the newborn. The larynx and glottic opening are more anterior and cephalad in the infant (infant’s C3-C4, adult’s C4-C5). The infant’s larynx is funnel shaped compared with the adult’s. The narrowest part of the adult larynx is at the vocal cord level, whereas in the child (younger than 10 years) the narrowest part is at the cricoid ring. The infant’s epiglottis is relatively large, stubby and “U” shaped. The vocal cords of the infant are in a diagonal (not horizontal) position within the larynx. This diagonal position makes it more likely to have the endotracheal tube lodge in the anterior commissure rather than slide down the trachea (Miller: Anesthesia, ed 6, pp 2369-2370; Stoelting: Basics of Anesthesia, ed 5, p 507).

Question 57

623. Which of the following operations would be associated with the LEAST incidence of postoperative nausea and vomit- ing (PONV) in a 5-year-old boy?
     A. Tonsillectomy
     B. Strabismus surgery
     C. Myringotomy tube placement D. Orchiopexy
     E. Inguinalherniorrhaphy

Answer 57

623. (C)Children at the highest risk for PONV include patients with a history of previous PONV and/or motion sick- ness, strabismus corrections and cases where narcotics are routinely needed, such as tonsillectomy, orchiopexy and herniorrhaphy. Brief procedures with minimal pain such as myringotomy tube placements have a low inci- dence of PONV. In cases where PONV is likely, prophylaxis is recommended (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, p 867).

Question 58

624. Anomalies and features associated with Down syndrome include A. Smaller tracheas
     B. Atlanto-occipital instability C. Thyroid hypofunction
     D. Endocardial cushion defect E. Alloftheabovearecorrect

Answer 58

624. (E)Down syndrome (trisomy 21) occurs in 1 in 700 to 1000 live births. There are many significant associated conditions. Congenital cardiac lesions are seen in about 40% of these patients (about one half are endocardial cushion defects; one fourth are ventricular septal defects; other lesions include patent ductus arteriosus, atrial sep- tal defects, tetralogy of Fallot) and commonly necessitate prophylactic antibiotics. Other findings include short neck, small mouth, narrow nasopharynx, large tongue, thyroid hypofunction (50%), atlanto-occipital instabil- ity (15% to 20% that is most often asymptomatic), and smaller airways. Despite these abnormalities, tracheal intubation is usually not difficult in the hands of an experienced anesthesiologist. The size of the endotracheal tube used to create an air “leak” with increasing airway pressure should be one to two sizes smaller because of the smaller trachea (e.g., in children age 18 months to 8 years the endotracheal tube size is 1 mm smaller) (Miller: Anesthesia, ed 6, p 1099; Shott, SR: Down syndrome: Analysis of airway size and a guide for appropriate intubation, Laryngoscope, 110:585-592, 2000; Hines: Stoelting’s: Anesthesia and Co-Existing Disease, ed 5, pp 611-612).

Question 59

625. Congenital syndromes frequently associated with cardiac abnormalities include all of the following EXCEPT A. Tracheoesophageal fistula
B. Meningomyelocele
C. Omphalocele
D. Gastroschisis
E. Congenitaldiaphragmatichernia

Answer 59

625. (D)Congenital cardiac abnormalities frequently occur in association with congenital diaphragmatic hernias, tra- cheoesophageal fistulas, meningomyeloceles, and omphaloceles. Gastroschisis is rarely associated with other congenital anomalies (Hines: Stoelting’s: Anesthesia and Co-Existing Disease, ed 5, pp 593-598, 608-609).

Question 60

626. Appropriate management of a neonate born with congenital diaphragmatic hernia (CDH) should include A. Ventilation of the lungs with a bag and mask to keep saturation greater than 95%
     B. Insertion of an orogastric tube
     C. Expansion of the hypoplastic lung with positive-pressure ventilation
     D. Hyperventilation to keep the PaCO2 below 40 and pH greater than 7.40 E. Rapidtransporttotheoperatingroomforsurgicalcorrection

Answer 60

626. (B)Newborns with CDH present with respiratory distress immediately after birth. They often have a flat (scaphoid) abdomen because some of the intestines herniate into the chest and are therefore not in the abdomen. Immedi- ate care includes endotracheal intubation for ventilatory support and placement of an orogastric or nasogastric tube to evacuate the stomach. Ventilation of the lungs with a bag and mask may cause more respiratory com- promise by producing gastric and intestinal distention and is contraindicated. When ventilating the newborn with an endotracheal tube, you must remember not to try to expand the lungs to normal size because the lungs are hypoplastic and prone to rupturing and producing a pneumothorax. Although at one time hyperventila- tion was recommended, more recently better outcomes have been found when permissive hypercarbia has been used (Paco2 45-55 mm Hg range). Associated congenital anomalies include CNS anomalies (e.g., spina bifida, hydrocephalus, anencephaly), cardiovascular (e.g., hypoplastic left heart syndrome, atrial and ventricular septal defects, coarctation, tetralogy of Fallot), gastrointestinal (e.g., malrotation, atresia), and genitourinary (e.g., hypospadias). Rushing the child to the operating room does not increase survival. It appears better to stabilize the child and look for associated congential anomalies (seen in up to 50% of these children) before proceeding with surgery (Fleisher: Anesthesia and Uncommon Diseases, ed 5, pp 626-630; Hines: Stoelting’s: Anesthesia and Co-Existing Disease, ed 5, pp 593-594).

Question 61

627. Factors associated with an increased incidence of laryngospasm include all of the following EXCEPT A. Younger age (

Answer 61

627. (E)Respiratory adverse events (RAE) are common in children undergoing noncardiac surgeries. They are more often associated with younger children (5 years of age), in children with a recent URI (although a few studies question this), in children with airway anomalies (e.g., cleft palate, subglot- tic stenosis, Pierre Robin syndrome), and when a laryngeal mask airway is used, compared with the use of mask anesthesia (Flick et al. Risk factors for laryngospasm in children during general anesthesia. Pediatric Anesthesia, 18:289-296, 2008; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 1161-1162).

Question 62

628. Which of the following statements regarding perioperative cardiac arrest in children is NOT CORRECT? A. Cardiac arrest is more common in neonates than infants or older children
     B. “Equipment related” causes occur in more than 25% of cardiac arrests
     C. Resuscitation is more often successful if the cause is anesthesia-related rather than non-anesthesia related D. Many cases of cardiac arrest occur in children with concomitant congenital heart disease
     E. Emergencysurgeryisassociatedwithgreaterthan5timesthechanceofacardiacarrest

Answer 62

628. (B)Perioperative cardiac arrest is often defined as the need for cardiopulmonary resuscitation or death during anes- thesia care (OR and postanesthesia care unit [PACU]). It is more than 4 times greater in neonates (0-30 days) than infants or children. Causes of cardiac arrest vary from study to study and often include medication related (e.g., inhalation or intravenous overdosage, succinylcholine-induced dysrhythmia, medication “swaps”), drug related (e.g., high spinal anesthesia, local anesthetic toxicity, opioid-induced respiratory depression, inadequate reversal of muscle relaxants), cardiovascular related (e.g., hemorrhage, hyperkalemia, vagal reflexes, embolism, sepsis), respiratory related (e.g., inadequate ventilation, loss of the airway, aspiration, pneumothorax), and equipment related (e.g., disconnects, stuck valves). Equipment-related causes are relatively rare causes of car- diac arrest (about 4% of cases). About 90% of cardiac arrests due to anesthesia-related episodes are reversed (adequate native heartbeat and blood pressure for at least 20 minutes after the arrest). If the cardiac arrest is not anesthesia-related, outcome is worse (only about 50%-60% are reversed). Regardless of surgical procedure, children with congenital heart disease have a greater chance of a cardiac arrest. Emergency surgery is associated with a six times greater incidence of cardiac arrest than elective surgery (Flick et al: Perioperative cardiac arrests in children between 1988 and 2005 at a tertiary referral center. Anesthesiology, 106:226-237, 2007; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 1110-1116).

Question 63

629. Klippel-Feil syndrome is associated with A. Kyphoscoliosis
     B. Renal anomalies
     C. Congenital heart abnormalities D. Cervical spine instability
     E. Allarecorrect

Answer 63

629. (E)Klippel-Feil syndrome (1 in 42,000 births) is characterized by musculoskeletal abnormalities (short neck which results from reduction in the number of cervical vertebra due to cervical vertebral fusion, kyphoscoliosis in 50%of patients, micrognathia, spinal canal stenosis), renal anomalies (33%), congenital heart disease (most commonly VSD), and hearing impairment. The most important consideration in the anesthetic management of these patients is a possibility of cervical spine instability, which can result in neurologic damage during direct laryngoscopy. Lateral and anteroposterior flexion-extension neck radiographs should be performed to assist in the evaluation of the stabil- ity of the cervical spine. Cervical MRI should be considered to assess neurologic function. Evaluation for congenital heart disease, as well as assessment of current respiratory and renal function should be done (Fleisher: Anesthesia and Uncommon Diseases, ed 5, pp 294-296; Hines: Stoelting’s: Anesthesia and Co-Existing Disease, ed 5, p 465).

Question 64

630. Which of the following statements regarding the Mapleson D breathing circuit is FALSE?
     A. It is an semi-open breathing system
     B. It has a proximal fresh gas inflow and a distal overflow valve
     C. With an inspiratory to expiratory (I:E) breathing ratio of 1:2, rebreathing is eliminated with spontaneous ventila-
     tion when the fresh gas flow is 3 times the minute ventilation
     D. To eliminate rebreathing, higher fresh gas flows are needed with controlled ventilation than with spontaneous
     ventilation
     E. TheMaplesonDcircuitisthemostwidelyusedoftheMaplesoncircuitsforpediatricanesthesia

Answer 64

630. (D)All of the statements are correct except for D. To eliminate rebreathing, higher fresh gas flows are needed with spontaneous ventilation than with controlled ventilation (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 276-278).

Question 65

631. Which of the following is LEAST likely to reduce the incidence of postoperative apnea in preterm infants undergoing surgery for inguinal hernia repair?
     A. Delaying operation until 60 weeks post conception
     B. Preoperative correction of anemia
     C. Caffeine administration
     D. Ketamine administration
     E. Spinalanestheticwithoutsedation

Answer 65

631. (D)At birth, the respiratory center of newborns is not fully developed. Newborns not uncommonly show two types of pauses in respiration. Periodic breathing exists if the pauses are short (i.e., 5-10 seconds) and not associated with a decrease in heart rate or oxygen saturation. Episodes of central apnea of infancy, also called apnea and bradycardia (A&B) spells, are longer and more significant. With A&B spells, the respiratory pauses are usu- ally greater than 15 to 20 seconds and are associated with a decrease in heart rate (38 weeks GA) who have not reached 44 weeks PCA and healthy preterm infants (

Question 66

632. Air should not be used to identify the epidural space in children because of the risk of A. Venous air embolism
     B. Infection
     C. Epidural hematoma
     D. Subcutaneous emphysema E. Neurologiccomplications

Answer 66

632. (A)The loss of resistance technique used when placing an epidural needle into the epidural space of a child should be done with saline and not air to decrease the risk of an air embolism. Note that the loss of resistance is much more subtle in the child, compared with the adult, when the epidural space is located (Motoyama: Smith’s Anes- thesia for Infants and Children, ed 7, p 476).

Question 67

633. Induction of general anesthesia for an elective operation should be delayed how many hours after breast feeding? A. 2 hours
B. 4 hours
C. 6 hours
D. 8 hours
E. NofastingneededbecausebreastmilkisOK

Answer 67

633. (B)The fasting recommendations to reduce the risk of pulmonary aspiration is commonly called the 2-4-6-8 rule.(ASA task force on preoperative fasting: Practice guidelines for preoperative fasting and the use of pharmaco- logic agents to reduce the risk of pulmonary aspiration: Application to healthy patients undergoing elective pro- cedures, Anesthesiology 90:896-905, 1999; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 265, 321, 882).

Question 68

634. In the infant, hypothermia can be manifested as A. Metabolic acidosis
     B. Prolonged duration of action of nondepolarizing muscle relaxants C. Hypoglycemia
     D. Respiratory depression
     E. Allarecorrect

Answer 68

634. (E)In neonates or infants, hypothermia can result in increased total body O2 consumption, metabolic acidosis, hypoglycemia, delayed awakening, prolonged duration of action of nondepolarizing muscle relaxants, and depression of ventilation. Therefore, monitoring the body temperature and maneuvers to minimize or eliminate significant loss of body heat during anesthesia for neonates and small infants are essential during the periopera- tive period (Miller: Anesthesia, ed 6, pp 516, 2371, 2862; Morgan: Clinical Anesthesiology, ed 4, p 924).

Question 69

635. Necrotizing enterocolitis has all of the following characteristics EXCEPT
     A. Most have thrombocytopenia (

Answer 69

635. (D)Necrotizing enterocolitis (NEC) classically occurs in premature infants and in infants with low birth weight (typically less than 2500 g) and carries a high mortality rate (10%-30% and higher in severely affected very low birth weight infants). In newborns less than 1500 g, the incidence is 10% to 20%. These children may be aci- dotic, hypoxic, and in shock. Most have thrombocytopenia (50,000-70,000/mm3) and prolonged prothrombin time (PT) and activated partial thromboplastin time (aPPT). Necrotizing enterocolitis (NEC) follows intestinal mucosal injury from ischemia. It is most commonly associated with decreased cardiac output in the presence of fetal asphyxia or postnatal respiratory complications in the early postnatal period. Other factors associated with the pathogenesis of necrotizing enterocolitis include a history of umbilical artery catheterization, enteral feeding of small preterm infants, bacterial infection, polycythemia, and gram-negative endotoxemia. Although umbilical artery catheters are often used in the newborn period, these should be removed if NEC develops, because they may compromise mesenteric blood flow. Unless there is evidence of intestinal necrosis or perfora- tion, nonoperative therapy should be instituted. This includes cessation of enteral feeding, decompression of the stomach, administration of broad-spectrum antibiotics, fluid and electrolyte therapy, parenteral nutrition, and correction of hematologic abnormalities. Inotropic drugs may be needed in the presence of shock (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 600-601; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 552-555).

Question 70

636. The LEAST useful analgesic for prevention/treatment of tonsillar pain A. Acetaminophen
     B. Ropivacaine infiltration C. Dexmedetomidine
     D. Codeine
     E. Ketorolac

Answer 70

636. (C)For the treatment of postoperative pain, regional anesthesia including local infiltration, narcotics and nonopioid analgesics such as acetaminophen and ketorolac are useful. Ketorolac should not be given to patients when you are concerned about postoperative bleeding, such as after a tonsillectomy. Although dexmedetomidine could provide analgesia, it is not commonly used for postoperative analgesia because of its expense and the need for an IV (See also answer to question 616) (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 866-867).

Question 71

637. Which of the following statements concerning sudden infant death syndrome (SIDS) is true
     A. SIDS most frequently occurs from 1 to 3 years of age
     B. Risk of SIDS is the same with lower birth weight infants as with normal birth weight infants C. Maternal smoking is associated with a higher incidence of SIDS
     D. The risk of SIDS is increased with a recent general anesthetic
     E. SleepinginthepronepositionhasalowerfrequencyofSIDSthansleepinginthesupineposition

Answer 71

637. (C)Sudden infant death syndrome (SIDS) is the unexplained death of an infant that is younger than 1 year of age. The peak age of SIDS is 3 to 4 months and is rare during the first month of life. Epidemiologic studies show an increased chance of SIDS with low birth weight infants, maternal smoking, maternal cocaine use, low socio- economic status, and with African Americans. There is no association with general anesthesia. Recently it has been noted that infants that sleep in the supine position have a lower rate of SIDS than infants who sleep in the prone position (Barash: Clinical Anesthesia, ed 5, pp 1193-1194).

Question 72

638. A 5-year-old girl with hemolytic-uremic syndrome is brought to the OR for placement of a dialysis catheter. Medical issues typical for this disease include
     A. Anemia
     B. Thrombocytopenia
     C. Increased intracranial pressure D. Pancreatitis
     E. Allarecorrect

Answer 72

638. (E)Hemolytic-uremic syndrome (HUS) is a commonly acquired cause of acute renal failure in children. Patients present with abdominal cramping, bloody diarrhea and vomiting; it is often caused by the toxin from Esch- erichia coli O157. About 10% of children with bloody diarrhea caused by E. coli O157 progress to HUS. Hemolytic-uremic syndrome (HUS) is characterized by a triad of microangiopathic hemolytic anemia (Hgb levels around 4-5 g/dL), thrombocytopenia (platelet destruction as well as sequestration of platelets in the liver and spleen), and acute nephropathy. Although the age of children most frequently affected by this disease is between 6 months and 4 years, HUS can occur from the neonatal period through adulthood. Occasion- ally CNS abnormalities develop (e.g., decreased levels of consciousness, seizures, and at times cerebral edema and increased intracranial pressure [ICP]). Pancreatitis is common and CHF may develop as a result of fluid overload, hypertension and myocardial depression from the toxins. Treatment is supportive and many of these children will require dialysis. The mortality rate is less than 5% (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, p 424; Miller: Anesthesia, ed 6, pp 2859-2861).

Question 73

639. A 3-year-old child status postresection of Wilms’ tumor at age 2 years is receiving doxorubicin (Adriamycin) and cyclophosphamide for metastatic disease. The patient is scheduled for placement of a Hickman catheter for continued chemotherapy. Anesthetic concerns related to this patient’s chemotherapeutic treatment include all of the following EXCEPT
     A. Thrombocytopenia
     B. Inhibition of plasma cholinesterase C. Cardiac depression
     D. Pulmonary fibrosis
     E. Hypertension

Answer 73

639. (D)Wilms’ tumor, also called nephroblastoma, is a common malignant abdominal malignancy of children. Children commonly present with increasing abdominal girth and have a palpable mass. Peak age of diagnosis is 1 to 3 years of age. Renal function is usually preserved but hypertension, often mild, is common (60%). Treatment consists of surgery, radiation, and chemotherapy. Chemotherapeutic drugs used in this tumor include actinomycin, doxo- rubicin (Adriamycin), vincristine, and cyclophosphamide (Cytoxan). Bone marrow suppression (e.g., anemia, thrombocytopenia) can occur with all cytotoxic drugs. Because cardiomyopathy can occur with cyclophospha- mide (>100 mg/m2) and with doxorubicin (>220 mg/m2), preoperative echocardiography should be considered even in asymptomatic patients. Late cardiac dysfunction may develop 7 to 14 years after treatment. Alkylating agents, such as cyclophosphamide, inhibit plasma cholinesterases, which may affect the metabolism of succinyl- choline. Pulmonary fibrosis and/or pneumonitis can occur in patients who have received bleomycin (the patient in this case did not receive bleomycin). This pulmonary toxicity may be related to high inspired oxygen concen- trations and excessive fluid administration. Vincristine has several CNS side effects, including peripheral neu- ropathy, impaired sensorium, and encephalopathy and renal toxicity (Hines: Stoelting’s Anesthesia and Co-Existing Disease, ed 5, pp 628-629; Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 691-692, 1064-1067).

Question 74

640. Preoperatively, hypotension (i.e., decompensated shock) is characterized by a systolic blood pressure (SBP) A. Less than 60 mm Hg for the term neonate (0 to 28 days old)
     B. Less than 70 mm Hg for infants 1 to 12 months old
     C. Less than 70 mm Hg + (2 × age in years) for children 1 to 10 years old
     D. Less than 90 mm Hg for children 10 years or older E. Alloftheabovearecorrect

Answer 74

640. (E)Shock occurs when perfusion to vital organs is inadequate to meet the organ’s metabolic demands. When shock is developing, cardiac output is initially well maintained by increasing the heart rate and myocardial contrac- tility. When cardiac output falls, blood pressure can only be maintained by a compensatory vasoconstriction. Shock is classified as compensated shock (systolic blood pressure in the normal range) or decompensated shock (systolic blood pressure less than the fifth percentile for age). If hypotension is present, one must be vigorous in treatment. Treatment is often begun with volume expansion; however, other causes of hypotension must be considered and treated as necessary (e.g., tension pneumothorax, pericardial tamponade, neurologic injury). The median (50th percentile) systolic blood pressure in children 1 to 10 years old is approximated by the formula: 90 mm Hg + (2 × age in years). Hypotension (i.e., decompensated shock) is based on systolic blood pressures and is correctly described in each of the choices in the question (2005 American Heart Association Guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation, 112:167, 2005).

Question 75

641. During peanut retrieval from the left mainstem bronchus, the foreign body becomes lodged in the trachea and is pushed back, but goes now into right mainstem bronchus. Air movement is impossible with bag and mask and the patient’s heart rate falls to 30 beats per minute. The most appropriate next step would be to
     A. Intubate the left mainstem
     B. Intubate the right mainstem
     C. Attempt the Heimlich maneuver D. Institute cardiopulmonary bypass E. Performanemergenttracheostomy

Answer 75

641. (A)In this life-threatening situation, the anesthesiologist should intubate the child immediately and advance the endotracheal tube into the left mainstem bronchus. Bradycardia is the most common antecedent rhythm to cardiac arrest in the pediatric population. The most common cause of bradycardia in infants and children is hypoxia, vagal stimuli, or a side effect of medication. In the present case, the child is bradycardic from severe hypoxia, caused by a complete obstruction of the airway. The mucosa in the left mainstem bronchus where the peanut was originally embedded most likely became sufficiently edematous to completely obstruct the lumen of the left mainstem bronchus. The patient might not have become hypoxic from this alone, but after attempting retrieval, the foreign became lodged in the trachea and had to be pushed back. Unfortunately, the peanut made its way into the right mainstem bronchus, effectively obstructing all airflow to the lungs.To avoid the problem of losing a foreign body before retrieval is complete, the forceps and the bronchoscope should be withdrawn simultaneously. Performing an emergency tracheostomy would not bypass the distal airway obstructions in the left mainstem bronchus or the peanut in the right mainstem bronchus and is thus a useless measure. Attempting the Heimlich maneuver would only bring the peanut into the trachea, where it could again become trapped and create more airway obstruction and irritation. Intubating the right mainstem will not relieve the airway obstruction from the peanut, but intubating the left mainstem and using a smaller sized tube to get past the swollen portion would be the most rapid and effective way of rescuing the child. Instituting cardiopul- monary bypass might be an option; however, it would take considerable time and would increase the child’s morbidity if not mortality (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 816-817, 1128).

Question 76

642. Each of the following results in a reduction of the incidence of nausea and vomiting in children undergoing strabismus surgery EXCEPT
     A. Withholding oral intake
     B. Premedication with clonidine 4 mg/kg orally
     C. Dexamethasone 0.15-1 mg/kg IV
     D. Ondansetron 50-200 μg/kg IV
     E. Gastriccontentevacuationbeforeemergencefromanesthesia

Answer 76

642. (E)Prophylaxis for PONV is recommended for patients undergoing strabismus surgery, because untreated, the incidence is 40% to 90% of patients. No benefit was demonstrated with the use of anticholinergic medications or with gastric content evacuation before emergency from anesthesia. Benefits were demonstrated with all of the other answers and with the use of droperidol, metoclopramide and by avoiding narcotic analgesics. Avoiding the maintenance use of nitrous oxide is controversial (Motoyama: Smith’s Anesthesia for Infants and Children, ed 7, pp 780-781).