Pediatric

Question 1

How does the oxygen consumption of a neonate compare with that of an adult?

Answer 1

1. The oxygen consumption of a neonate is about twice that of an adult. In neonates
   the oxygen consumption increases from 5 mL/kg per minute at birth to about
   7 mL/kg per minute at 10 days of life and 8 mL/kg per minute at 4 weeks of
   life. Oxygen consumption gradually declines over the subsequent months.

Question 2

2. How does the cardiac output of a neonate compare with that of an adult?

Answer 2

2. The cardiac output of a neonate is 30% to 60% higher than that of adults. This helps
   to meet the increase in oxygen demand neonates have as compared with
   adults.

Question 3

3. Are changes in the cardiac output of a neonate more dependent on changes in the
   heart rate or stroke volume?

Answer 3

3. Changes in the cardiac output of a neonate or infant are dependent on changes
   in the heart rate, because stroke volume is relatively fixed by the lack of
   distensibility of the left ventricle in this age group. The neonate’s myocardium
   depends heavily on the concentration of ionized calcium, such that hypocalcemia
   can significantly depress myocardial function.

Question 4

4. How does the position of the oxyhemoglobin dissociation curve in a neonate
   compare with that of an adult? Describe how this affects the affinity of oxygen for
   hemoglobin. At what age does the curve approximate that of an adult?

Answer 4

4. In neonates, the oxyhemoglobin dissociation curve is shifted to the left. This
   reflects a P50 lower than 26 mm Hg, meaning that less of a PaO2 is required for a
   50% saturation of hemoglobin. Conversely, the oxygen is more tightly bound to
   hemoglobin in neonates, necessitating a lower PaO2 for release of oxygen to the
   tissues. This occurs as a result of fetal hemoglobin. The position of the
   oxyhemoglobin dissociation curve becomes equal to that of adults by 4 to 6
   months of age

Question 5

5. How does the hemoglobin level of a neonate compare with that of an adult? How
   does the hemoglobin level change as the infant progresses to 2 years old?

Answer 5

5. The hemoglobin level of a neonate is approximately 17 g/dL. This, along with the
   increase in cardiac output, helps to offset the increase in oxygen requirements
   characteristic of neonates. At 2 to 3 months of age the hemoglobin of infants
   decreases to about 11 g/dL during the time period when fetal hemoglobin is being
   replaced by adult hemoglobin. This is termed the physiologic anemia of infancy,
   which may persist for a few months. During the remainder of the first year of
   life the hemoglobin level gradually increases and continues to do so until puberty,
   when hemoglobin levels approach adult hemoglobin levels

Question 6

6. What hemoglobin level is worrisome in the newborn? What hemoglobin level is
   worrisome in infants older than 6 months of age?

Answer 6

6. A hemoglobin level of 13 g/dL or less is worrisome in the newborn. In infants older
   than 6 months of age, a hemoglobin level less than 10 g/dL is worrisome.

Question 7

7. At what age does the foramen ovale close? What percent of adults have a probe
   patent foramen ovale?

Answer 7

7. The foramen ovale closes between 3 and 12 months of age. Twenty to thirty percent
   of adults have a probe patent foramen ovale

Question 8

8. How well do neonates reflexively respond to hemorrhage as compared with adults?

Answer 8

8. Because of the decreased ability of neonates to vasoconstrict in response to
   hypovolemia, neonates are less able to tolerate hemorrhage with vasoconstrictive
   responses

Question 9

9. How does alveolar ventilation in neonates compare with that of adults?

Answer 9

9. Alveolar ventilation in neonates is 4 to 5 times higher than that of adults.

Question 10

10. How does the tidal volume per weight in neonates compare with that of adults?

Answer 10

10. Tidal volume per weight in neonates is similar to that of adults.

Question 11

11. How does the respiratory rate in neonates compare with that of adults?

Answer 11

11. The respiratory rate in neonates is three to four times higher than that of adults.

Question 12

12. How does carbon dioxide production in neonates compare with that of adults?
    How does the PaCO2 in neonates compare with that of adults?

Answer 12

12. Carbon dioxide production in neonates is higher than that of adults. The PaCO2
    in neonates is similar to that of adults, despite the increase in production.
    This is due to the increase in alveolar ventilation in neonates when compared with
    adults. (

Question 13

13. How does the PaO2 change in the first few days of life?

Answer 13

13. The PaO2 in the first few days after birth increases rapidly. The initially low PaO2 is due
    to a decrease in the functional residual capacity and to the perfusion of alveoli
    filled with fluid. The functional residual capacity of neonates increases over the first
    few days of life until it reaches adult levels at about 4 days of age

Question 14

14. How predictable is the neonate’s response to hypoxia?

Answer 14

14. The neonate’s response to hypoxia is somewhat unpredictable, owing to the
    immaturity of the central nervous system’s regulatory centers for ventilation in
    this age group. Neonates have decreased ventilatory responses to hypoxemia and
    hypercarbia.

Question 15

15. What percent body weight in neonates is contributed by the extracellular fluid
    volume? How does this compare with an adult?

Answer 15

15. Extracellular fluid volume accounts for approximately 40% of the body weight of
    the neonate at birth. This compares with approximately 20% of body weight in
    adults being accounted for by extracellular fluid volume. The proportion of
    extracellular fluid volume to body weight in neonates approaches the adult
    proportion by 18 to 24 months of age.

Question 16

16. What are some ways in which infants and children maintain normal body
    temperature? Why is maintenance of normal body temperature more difficult in
    neonates and children than in an adult?

Answer 16

16. Some ways in which infants and children maintain normal body temperature
    include the metabolism of brown fat, crying, and vigorous movements. The
    metabolism of brown fat is stimulated by circulating norepinephrine. Children and
    infants, unlike adults, do not shiver to maintain their body temperature.
    Maintenance of normal body temperature is more difficult in neonates and infants
    than in adults because of their larger body surface area-to-volume ratio, as well
    as the relative lack of fat for insulation. (556)

Question 17

17. How effective is kidney function at birth? When does kidney function become
    approximately equivalent to that of an adult?

Answer 17

17. Kidney function at birth is immature. There is a decreased glomerular filtration
    rate, decreased sodium excretion, and decreased concentrating ability relative
    to that of an adult. Kidney function progressively matures over the first 2 years of
    life. Initially, in the first 3 months of life, kidney function increases rapidly to
    double or triple the glomerular filtration rate possible at birth. Kidney function
    then matures more slowly from 3 months to 24 months, when adult levels of
    kidney function are reached

Question 18

18. After fluid restriction, what is the maximum urine osmolarity possible for term
    neonates at birth? At what age are adult levels of urine concentrating abilities
    achieved?

Answer 18

18. After fluid restriction, the term neonate at birth can only concentrate urine to
    a maximum osmolarity of about 525 mOsm/kg. After 15 to 30 days of age,
    neonates are able to concentrate their urine to a maximum osmolarity of about
    950 mOsm/kg. Adult levels of urine concentrating ability are achieved by 6 to
    12 months of age. (550)

Question 19

19. What are some physiologic characteristics of neonates that explain the
    pharmacologic differences between pediatric and adult responses to drugs?

Answer 19

19. Some physiologic characteristics of neonates that explain the pharmacologic
    differences between pediatric and adult responses to drugs include an increased
    extracellular fluid volume, increased metabolic rate, decreased renal function,
    and decreased receptor maturity

Question 20

20. How is the uptake and distribution of inhaled anesthetics different in neonates and
    infants when compared with adults?

Answer 20

20. The uptake and distribution of inhaled anesthetics is more rapid in neonates than
    in adults. This is most likely due to a smaller functional residual capacity per
    body weight in neonates, as well as to greater tissue blood flow to the vessel-rich
    group. The vessel-rich group of tissues includes the brain, heart, kidneys, and
    liver. This group comprises approximately 22% of total body volume in neonates,
    as compared with the 10% of total body volume in adults.

Question 21

21. How does the minimum alveolar concentration (MAC) of inhaled anesthetics
    change from birth to puberty?

Answer 21

21. The minimum alveolar concentration (MAC) of inhaled anesthetics changes
    from birth to puberty. Preterm neonates have a lower MAC than term neonates,
    whose MAC is approximately 0.87% that of adults. The MAC of inhaled
    anesthetic agents is highest in infants 1 to 6 months old. The MAC is 30% less in
    full-term neonates for isoflurane and desflurane. Sevoflurane MAC at term is
    the same as at age 1 month.

Question 22

22. What is the effect of intracardiac shunting on the rapidity of anesthesia induction
    with halogenated anesthetic gases?

Answer 22

22. Patients with right-to-left intracardiac shunting have a slower inhaled induction
    of anesthesia, due to the volume of blood bypassing the lungs and not increasing
    its anesthetic level. This results in a slower rise in the arterial level of the
    anesthetic and a slower induction. This effect is most pronounced with
    less-soluble agents, such as desflurane and sevoflurane, and less pronounced with
    more-soluble agents, such as halothane and isoflurane. Left-to-right intracardiac
    shunts have little or no effect on the rapidity of induction

Question 23

23. What physiologic factors increase the sensitivity of neonates to the effects of
    intravenous anesthetics?

Answer 23

23. Physiologic factors that make neonates more sensitive to the effects of
    intravenous anesthetics include an immature blood-brain barrier and a decreased
    ability to metabolize drugs. They are more sensitive to highly protein-bound
    drugs because of the lower serum albumin and protein concentrations in
    neonates. In many cases the increased extracellular fluid volume and volume
    of distribution present in neonates offsets the increased sensitivity to intravenous
    drugs when compared with adults, thereby approximately equalizing the dose
    of initial intravenous injection of drug to achieve a given result. (

Question 24

24. How does the dose of thiopental change between neonates and adults?

Answer 24

24. The dose of thiopental required to produce loss of lid reflex is similar in neonates,
    children, and adults.

Question 25

25. How does the rate of plasma clearance of opioids differ between neonates and adults?

Answer 25

25. The rate of plasma clearance of opioids is decreased in neonates when compared with adults. (55

Question 26

26. Are neonates more or less sensitive to nondepolarizing neuromuscular blocking drugs than adults? How does the initial drug dose differ between these two groups?

Answer 26

26. Neonates are more sensitive than adults to nondepolarizing neuromuscular blocking drugs. This means that a lower plasma concentration of drug is required to produce similar pharmacologic results. Because of an increased extracellular fluid volume and increased volume of distribution in neonates when compared with adults, the initial dose of nondepolarizing neuromuscular blocking drug in these two age groups is similar. This is true despite the increased sensitivity to the drug for neonates.

Question 27

27. How does the duration of action of nondepolarizing neuromuscular blocking drugs differ between neonates and adults?

Answer 27

27. The duration of action of nondepolarizing neuromuscular blocking drugs in neonates may be prolonged while the mechanisms for clearance are still immature in the neonate. For example, the clearance of d-tubocurarine parallels the glomerular filtration rate at various ages. There exists a great deal of variability among pediatric patients with regard to the duration of effect of nondepolarizing neuromuscular blocking drugs. Monitoring of the neuromuscular junction with a peripheral nerve stimulator is recommended when nondepolarizing neuromuscular blocking drugs are administered to this population

Question 28

28. How does the dose of neostigmine necessary to antagonize neuromuscular blockade in the neonate compare with the dose necessary in the adult? How does this affect clinical practice?

Answer 28

28. The dose of neostigmine necessary to antagonize neuromuscular blocking drugs in the neonate is less than that of adults, although clinically the same dose may be used. (

Question 29

29. How does the dose of succinylcholine necessary to produce neuromuscular blockade in the infant and neonate compare with the dose necessary in the adult?

Answer 29

29. The dose of succinylcholine per body weight necessary to produce neuromuscular blockade in the neonate and infant is increased from the adult dose. This is presumed to be due to the increase in extracellular fluid volume and increase in volume of distribution in neonates and infants. (551)

Question 30

30. What is the recommendation for fluid maintenance and replacement in the pediatric population?

Answer 30

30. Fluid maintenance and replacement in the pediatric population is based on the patient’s age and metabolic rate, underlying disease process, type and extent of surgery, and anticipated fluid translocation. The maintenance rate of pediatric patients is related to their metabolic demand, which in turn is related to the ratio of body surface to weight. Hourly fluid requirements are estimated to be 4 mL/kg for children up to 10 kg, an additional 2 mL/kg for each kilogram of body weight between 10 kg and 20 kg, and an additional 1 mL/kg for each kilogram of body weight above 20 kg. Additional fluid replacement may be required for the patient’s initial fluid deficit, third-space losses, or other losses. Fluid replacement can be guided by the patient’s systemic blood pressure, tissue perfusion, and urine outpu

Question 31

31. What is the goal for urine output when monitoring the intraoperative volume status of the pediatric patient

Answer 31

31. A goal for urine output when monitoring the intraoperative volume status in the pediatric patient is 0.5 to 1 mL/kg/hr. (

Question 32

32. When should glucose administration be considered in the pediatric population?

Answer 32

32. Glucose administration in the pediatric patient can be considered in patients who are at a high risk for hypoglycemia. Pediatric patients at a high risk for hypoglycemia include newborns of diabetic mothers or neonates whose hyperalimentation has been discontinued. Maintenance fluids of 5% dextrose in 0.45 normal saline can be administered to these patients intraoperatively as a piggy-back infusion by pump with care not to bolus glucose-containing solutions.

Question 33

34. What is a reasonable approach to replace preoperative fluid deficits in pediatric patients?

Answer 33

33. Nonglucose containing isotonic fluids are most appropriate to replace losses. These include lactated Ringer solution and Plasma-lyte A, which both contain physiologic levels of sodium and potassium. Normal saline can be used, but with supraphysiologic levels of sodium and chloride, a hyperchloremic, hypernatremic, metabolic acidosis can occur with the administration of large volumes.

Question 34

34. What is a reasonable approach to replace preoperative fluid deficits in pediatric patients?

Answer 34

34. Preoperative fluid deficits in the pediatric patient can be estimated by multiplying the number of hours the patient has been NPO by the hourly maintenance fluid requirement based on the 4-2-1 rule. Replace 50% of this deficit in the first hour, and the remaining 50% in the second hour. Minimizing preoperative fluid deficits by allowing clear liquids to be ingested orally up to 2 hours before surgery is an effective strategy to minimize preoperative deficits

Question 35

35. How are third-space losses and fluid replacement estimated according to the degree of invasiveness of the surgery? How does this contribute to an overall fluid management strategy for pediatric patients?

Answer 35

35. For minimally invasive surgery, third-space losses are estimated to be 0 to 2 mL/kg/hr. This includes superficial surgery such as strabismus repair. For mildly invasive surgery such as ureteral reimplantation, these losses are estimated at 2 to 4 mL/kg/hr. For moderately invasive surgery such as elective bowel reanastomosis, fluid losses are estimated at 4 to 8 mL/kg/hr; and for maximally invasive surgery such as bowel resection for necrotizing enterocolitis, fluid losses are estimated to be 8 to 10 mL/kg/hr or greater. To this hourly fluid administration is added the maintenance fluid requirement according to the 4-2-1 rule, the preoperative fluid deficit as noted previously, and replacement for blood loss. The latter is replaced with 3 mL of isotonic crystalloid for each milliliter of estimated blood loss, or 1 mL of colloid such as 5% albumin for each milliliter blood loss, or milliliter for milliliter of blood product such as packed red blood cells

Question 36

36. What formula can be used to help guide the anesthesiologist with blood loss replacement?

Answer 36

36. A formula that may be used by the anesthesiologist to help guide blood loss replacement is: MABL mL ð Þ¼ EBVðmLÞðpatient Hct minimum acceptable HctÞ=patient Hct MABL, maximum allowable blood loss; EBV, estimated blood volume; Hct, hematocrit. The estimated blood volume is between 70 mL/kg at about 5 years of age to 100 mL/kg in the premature newborn. This formula should be applied to the pediatric patient prior to surgery so that when the threshold is reached, it is immediately recognized and the transfusion initiated.

Question 37

37. What is the transfusion threshold for packed red blood cells (PRBC) in pediatric patients? What is the expected hemoglobin increase with PRBC transfusion? What special precautions are needed for PRBC transfusion in neonates and young infants?

Answer 37

37. The pediatric patient’s transfusion threshold varies greatly according to the patient’s underlying physiology, age, nature of the surgery, and anticipated ongoing blood loss, and must be individualized. For patients with cyanotic heart disease, a hemoglobin threshold of 12 to 13 g/dL is often used. For otherwise healthy acyanotic patients, a lower threshold of 7 to 8 g/dL is often used; 10-15 mL/kg of PRBC should increase hemoglobin by 2 to 3 g/dL. Leukocyte reduction and irradiation of PRBCs minimizes the risk of cytomegalovirus transmission, graft versus host reaction, and HLA allosensitization. These procedures are used for infants less than 4 months, immunocompromised patients, and transplant or potential transplant recipients

Question 38

38. What is the indication for a platelet transfusion in pediatric patients, and what is the expected response to platelet transfusion?

Answer 38

38. The usual indication for platelet transfusion in a pediatric patient is a platelet count below 50,000 to 100,000/dL, accompanied by surgical bleeding; 5 to 10 mL/kg of platelet concentrate transfusion should increase platelet count by 50,000 to 100,000/dL.

Question 39

39. What is the usual indication for transfusion of fresh frozen plasma (FFP) in pediatric patients? What is the expected response to FFP administration?

Answer 39

39. Indications for FFP administration in pediatric patients include massive transfusion resulting in markedly reduced levels of coagulation proteins and hemodilution from cardiopulmonary bypass in small infants. Ten to fifteen milliliters per kilogram of FFP will increase most coagulation factors by 15% to 20%, which is often sufficient to improve hemostasis

Question 40

40. What is the usual indication for administration of cryoprecipitate in pediatric patients? What is the expected response to cryoprecipitate administration?

Answer 40

40. Indications for cryoprecipitate administration in pediatric patients most often are low fibrinogen concentrations from massive hemorrhage or dilution from cardiopulmonary bypass. One unit of cryoprecipitate administered per 5 kg of patient weight is normally sufficient to restore adequate fibrinogen levels

Question 41

41. What are some other pharmacologic agents that will either reduce blood loss or help achieve hemostasis with major blood loss surgery in pediatric patients?

Answer 41

41. The lysine analogs E-aminocaproic acid and tranexamic acid reduce fibrinolysis by inhibiting plasmin. Recombinant factor VIIa is used for patients with factor VII deficiency or hemophiliacs with inhibitors to factors VIII and IX. It is also used in cases of massive hemorrhage such as cardiac surgery or trauma, as a life- saving measure to reduce bleeding. This agent causes a “thrombin burst” when exposed to tissue factor, resulting in massive activation of the coagulation cascade. Thrombotic complications have been reported with recombinant factor VIIa.

Question 42

42. What is the leading cause of difficult airway management in infants and young children? What are some genetic syndromes that cause this condition?

Answer 42

42. Micrognathia is the single most common cause of difficult mask ventilation and tracheal intubation in young pediatric patients. The preoperative airway assessment in children should involve visual inspection for micrognathia, as well as midface hypoplasia or other cranio-facial abnormalities. Pierre-Robin sequence, Goldenhar, and Treacher-Collins syndromes are the most commonly encountered conditions resulting in micrognathia.

Question 43

43. What is the general approach to the difficult pediatric airway, and how does it differ from the adult difficult airway?

Answer 43

spontaneous respiration; use adjuncts such as the laryngeal mask airway, videolaryngoscope, or fiber-optic bronchoscope to secure the airway; awaken the patient if possible if the airway cannot be secured; avoid neuromuscular blockade until the airway is secured; and have surgical backup for emergency tracheostomy for particularly difficult cases. The major difference between managing the pediatric versus adult airway is that young pediatric patients will not tolerate an “awake” intubation with topical anesthesia of the airway; they must have some level of moderate to deep sedation or general anesthesia. Also, cricothyrotomy is technically difficult in small patients and ventilation via this method ineffective. Thus, this method cannot be used in young pediatric patients.

Question 44

44. What history should be obtained from a preoperative evaluation of a pediatric patient? What are some considerations that are specific to the pediatric population with regard to the history and physical examination?

Answer 44

44. The preoperative history in the pediatric patient often comes from a parent. The history obtained should include such things as congenital anomalies, allergies, bleeding tendencies, and any recent exposure to communicable diseases. A special consideration for the pediatric population is whether the patient has had any recent upper respiratory tract infection, which makes it more likely that the patient will have increased secretions and airway hyperreactivity with anesthesia. Elective surgeries may be delayed in the presence of an upper airway infection. With regard to the airway examination, the presence of loose teeth should be evaluated, and removal of the loose tooth or teeth before airway manipulation should be considered.

Question 45

45. What preoperative laboratory data may be important in the pediatric population?

Answer 45

45. Laboratory data are typically unnecessary in the routine pediatric patient. Laboratory data should be ordered based on abnormalities in the history and physical examination. Urine pregnancy testing is practiced for menstruating females in many institutions.

Question 46

46. What are the recommendations for the preoperative ingestion of solids and clear liquids for pediatric patients?

Answer 46

46. The recommendations for the preoperative consumption of solids and clear liquids are now standardized. Clear liquids are generally allowed up to 2 hours before induction of anesthesia, breast milk up to 4 hours before induction, and milk or formula allowed up to 6 hours before induction. Solid foods should not be ingested sooner than 6 to 8 hours before anesthesia. These guidelines apply to all ages of pediatric patients.

Question 47

47. What are some considerations regarding the choice of premedicant in the pediatric patient? What are some drugs and their routes of administration for preoperative medication in the pediatric population?

Answer 47

47. Premedication of the pediatric patient should take into consideration the age of the patient, the patient’s underlying medical condition, the length of surgery, the mode of induction of anesthesia, and whether the patient will be staying in the hospital after the procedure. Infants younger than 6 months old typically do not require premedication, whereas patients between 9 months and 5 or 6 years old may benefit from premedication before separation from their parents. Premedicants may be administered orally, intravenously, intramuscularly, rectally, sublingually, transmucosally, or intranasally; however, the oral route is strongly preferred. One drug available and commonly used for premedication in the pediatric population is oral midazolam

Question 48

48. How can the induction of anesthesia be achieved in pediatric patients without an intravenous catheter in place?

Answer 48

48. In the pediatric patient without an intravenous catheter, anesthesia can be induced via inhalation. An inhalation induction can be achieved by initially having the child breathe 70% nitrous oxide and 30% oxygen, followed by incremental increases in the concentration of a volatile anesthetic. The only volatile anesthetic available for inhalation induction in the United States is sevoflurane, because it is much less pungent than the other volatile anesthetics. Other adjuncts that may be used to decrease patient anxiety and facilitate the induction of anesthesia under these circumstances include having the parents present during the time of induction, flavoring the anesthesia mask with pleasant scents, and maintaining a constant monotone conversation with the patient. A story can be told by the anesthesiologist to distract the patient during induction.

Question 49

49. What are some risks of an inhaled induction of anesthesia?

Answer 49

49. An inhaled induction of anesthesia has some inherent risks. First, while the pediatric patient is being induced, the anesthesiologist often increases concentrations of the volatile anesthetic to dangerous inspired concentrations of volatile anesthetic if maintained. Once anesthesia is induced it is important to reduce the inspired concentrations of volatile anesthetic to routine maintenance levels. This is especially true just before intubating the trachea, because connection of the circuit and ventilating the intubated patient with high inspired concentrations of volatile anesthetic while potentially distracted with endotracheal tube positioning is a risk. High inspired concentrations of volatile anesthetic, if continued, can lead to myocardial depression that is difficult to reverse. Another risk of an inhaled induction of anesthesia is that of laryngospasm. Laryngospasm, along with coughing, vomiting, and involuntary movement, can occur in stage 2 (the excitement phase) of induction of anesthesia. Laryngospasm is accompanied by a rocking-boat motion of the chest and abdomen as the patient attempts to inspire against a closed glottis. Laryngospasm should be treated by closing the pop-off valve and creating positive-pressure of about 10 cm H2O against the glottis. If necessary, positive pressure ventilation can be attempted. In most circumstances these will reverse the laryngospasm and the patient will spontaneously ventilate. Should these two interventions not reverse the laryngospasm, succinylcholine can be administered intravenously or intramuscularly. Succinylcholine is the neuromuscular blocking drug of choice under these circumstanc

Question 50

50. What is the indication for the placement of an intravenous catheter in the pediatric patient undergoing a surgical procedure?

Answer 50

50. The placement of an intravenous catheter should be done in every pediatric patient undergoing a surgical procedure other than for very short surgical procedures.

Question 51

51. How can the anesthesiologist regulate the intravenous fluids to be administered in the pediatric patient?

Answer 51

51. The administration of intravenous fluids in pediatric patients can be regulated by the use of a calibrated drip chamber yielding 60 drops/mL, and filled with only 50 to 100 mL of IV fluid, so as to minimize the risk that excessive amounts of fluid are accidentally administered

Question 52

52. How can the induction of anesthesia be achieved in pediatric patients with an intravenous catheter in place?

Answer 52

52. In the pediatric patient with an intravenous catheter, the induction of anesthesia can be achieved by the intravenous administration of an induction agent such as thiopental or propofol. This is the induction method of choice in patients at risk for the aspiration of gastric contents

Question 53

53. How can the induction of anesthesia be achieved in pediatric patients without an intravenous catheter in place and in whom an inhalation induction is not possible?

Answer 53

53. Another method of induction in the pediatric patient without an intravenous catheter and in whom an inhalation induction is not possible is by the intramuscular administration of ketamine. This method of induction is used most commonly in developmentally delayed or severely uncooperative children

Question 54

54. What is the concern regarding the use of succinylcholine in pediatric patients? What are some alternatives that may be used?

Answer 54

54. There are multiple concerns regarding the use of succinylcholine in pediatric patients. First, the administration of succinylcholine can result in cardiac arrhythmias, including bradycardia and, rarely, cardiac sinus arrest. The pretreatment of pediatric patients with atropine may reduce succinylcholine- induced bradycardia. Second, it is believed that in patients who have been administered succinylcholine and have subsequent masseter muscle rigidity, there may be impending malignant hyperthermia. Finally, there have been reports of pediatric patients who were otherwise healthy and went into irreversible cardiac arrest after the administration of succinylcholine. Many of these patients had hyperkalemia, rhabdomyolysis, and acidosis. It is postulated that these pediatric patients may have had undiagnosed myopathies. Postmortem muscle biopsies have shown many of them to have muscular dystrophy. The group at highest risk of this catastrophic event are males 8 years of age or younger. Because of these concerns, there is now a “black box warning” by the U.S. Food and Drug Administration prohibiting routine use of succinylcholine in pediatric patients. It is only indicated for airway emergencies, such as laryngospasm or rapid sequence induction. Some alternatives that may be used are the nondepolarizing neuromuscular blocking drugs, such as larger doses of vecuronium or rocuronium.

Question 55

55. Under what circumstances is succinylcholine accepted for use for neuromuscular blockade in the pediatric population?

Answer 55

55. Succinylcholine is accepted for use for rapid onset neuromuscular blockade in pediatric patients for the treatment of laryngospasm and in patients at high risk for aspiration of gastric contents in whom rapid sequence induction/intubation is indicated. (

Question 56

56. What are some physiologic characteristics of the pediatric airway that differ from the adult airway?

Answer 56

56. There are multiple physiologic differences between the pediatric airway and the adult airway. Pediatric patients tend to have a larger tongue relative to the size of their mouths. Particularly true in neonates is that the occiput is larger, so that placing the head in the neutral position naturally places the head in a position favorable for direct laryngoscopy. Extending the head can make direct laryngoscopy difficult. Thelarynx is more cephalad in pediatric patients, with the cricoid cartilage opposing the C4 vertebra rather than the C6 vertebra as in adults. The larynx is also more anterior. The epiglottisislonger, stiffer, andU shaped and hasmore of a horizontallie. The narrowest point of the airway is at the level of the cricoid cartilage in the presence of neuromuscular blockade. These differences between the pediatric airway and the adult airway are present until about the age of 8 years, after which the difference between the pediatric airway and the adult airway is mainly just a difference in size.

Question 57

57. Why has the classic teaching that uncuffed endotracheal tubes should be used for intubating the trachea of pediatric patients under the age of 8 years changed?

Answer 57

57. Because the narrowest point of the pediatric airway is at the level of the cricoid cartilage, it was believed that an endotracheal tube that passes easily through the larynx may cause ischemia or damage to the trachea distally. However, recent imaging studies challenge this notion, and the difference in diameter between the larynx and subglottis in younger children is minimal. Historically, uncuffed tubes were the standard of care in children younger than 8 years of age owing to concerns about subglottic stenosis and postextubation stridor. However, with the introduction of tubes with high volume–low pressure cuffs, recent studies suggest that there is no increased risk of airway edema with cuffed endotracheal tubes and that the use of cuffed endotracheal tubes may decrease the number of laryngoscopies and intubations due to inappropriate tube size. The risk of postintubation tracheal edema is greatest in children between 1 and 4 years of age, whether a cuffed or uncuffed ETT is used. Postintubation tracheal edema/croup can be treated with humidified gases and aerosolized racemic epinephrine. Dexamethasone has also been administered intravenously for the treatment of postintubation tracheal edema.

Question 58

58. What is the benefit of the administration of heated and humidified gases or using a condenser humidifier in children undergoing prolonged operations?

Answer 58

58. Because of their larger surface area to weight ratio, infants tend lose body heat much more rapidly than adults. This is particularly true in a cold operating room environment. The administration of heated and humidified gases or use of a condenser humidifier in children undergoing prolonged operations is useful in decreasing intraoperative heat loss and in avoiding decreases in body temperature. Warming the operating room, the use of radiant warmers, and warmed intravenous fluids are other methods of maintaining normothermia

Question 59

59. What are some signs the clinician may use to determine the adequacy of the depth of anesthesia for surgery in the pediatric population?

Answer 59

59. Signs for the adequacy of depth of anesthesia for surgery are the same for neonates, infants, and children as they are in adults. Those signs include blood pressure, heart rate, and skeletal muscle movement. Processed electroencephalographic technologies may be used as in the adult population, but are less reliable in younger children. (556

Question 60

60. When hypotension accompanies the administration of volatile anesthetics to neonates, what is it likely to be indicative of?

Answer 60

60. Hypotension in the neonate that accompanies the administration of volatile anesthetics is likely to be indicative of hypovolemia. (552)

Question 61

61. How does intraoperative monitoring in the pediatric population differ from intraoperative monitoring in the adult population?

Answer 61

61. Intraoperative monitoring in the pediatric population is not any different from intraoperative monitoring in the adult population undergoing comparable surgical procedures. Routine monitors should include blood pressure, heart rate, electrocardiogram, peripheral oxygen saturation, capnography, anesthetic gas concentration, and temperature monitoring. (5

Question 62

62. What problem may be encountered with the monitoring of end-tidal carbon dioxide concentrations in pediatric patients?

Answer 62

62. The monitoring of end-tidal carbon dioxide concentrations in small children, infants, and neonates may be complicated by large dead space introduced between the CO2 sampling line and the trachea by endotracheal tube connectors, condenser humidifiers, and elbow connectors at the end of the Y-piece of the anesthesia circuit. The small tidal volumes of these patients exacerbate the problem and can result in falsely low end-tidal CO2 readings. In addition, congenital heart disease patients with right-to-left shunting will have a falsely low end-tidal CO2 due to the blood bypassing the lungs. (556)

Question 63

63. How should the size of a blood pressure cuff be selected? What errors in blood pressure measurement may be encountered with an erroneously sized cuff?

Answer 63

63. An appropriately sized blood pressure cuff is one that is greater than one third of the circumference of the limb. A blood pressure cuff that is too small will result in artificially high blood pressures. The opposite is also true, that a blood pressure cuff that is too large will result in artificially low blood pressures. (556)

Question 64

64. What veins may be used to monitor the central venous pressure in the neonate? In infants? In children?

Answer 64

64. Central venous pressure can be monitored in the neonate via an umbilical vein catheter. The internal jugular vein, femoral vein, or subclavian vein can be used for central venous pressure monitoring in neonates, infants, and children. (549)

Question 65

65. What are some regional anesthetic blocks that can be administered in the pediatric population?

Answer 65

65. There are several procedures in which regional anesthetic techniques can be considered in the pediatric population. For circumcision or hypospadias repair, a penile block may be used. For inguinal hernia repair an ilioinguinal and iliohypogastric block may be used. For femur surgery, a fascia iliaca compartment block may be used. For arm and wrist surgery a brachial plexus block may be used. Intravenous regional anesthesia may also be used in the pediatric patient for tendon laceration repairs or extremity fractures. Caudal anesthesia is a common form of anesthesia and is used for postoperative pain relief in the pediatric population in whom the surgical site is below the level of the diaphragm. Conversely, a lumbar epidural anesthetic may also be used in the pediatric patient. (557, 558)

Question 66

66. What local anesthetic and what dose is commonly used in a caudal anesthetic? What is the approximate duration of the postoperative pain relief obtained from this caudal anesthetic? How is the length of the dural sac different in children and adults?

Answer 66

66. For caudal epidural anesthesia, the local anesthetic most commonly used is bupivacaine at a concentration of 0.125% to 0.25%, and ropivacaine at 0.1% to 0.2%. The volume is 0.5 to 1 mL/kg, up to a maximum of 20 mL. The duration of pain relief provided by this dose of local anesthetic in the caudal epidural space is 4 to 6 hours, therefore possibly providing some postoperative pain relief. The dural sac extends more caudad in children than in adults, making inadvertent intrathecal injection a possibility. The risks of caudal epidural anesthesia are minimal. (557)