Pediatric Anatomy, Physiology, Growth and Development, and Normal Vital Signs Practice Questions

25 multiple-choice questions on Pediatric anatomy, physiology, growth and development, and normal vital signs for paramedic and EMT students, from Chapter 44 (Pediatric Emergencies). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. Infants often breathe irregularly. To get an accurate respiratory rate in a calm 3-month-old, you should count for:

   1. A. 15 seconds, then multiply by 4
   2. B. 30 to 60 seconds, while calm
   3. C. 6 seconds, then multiply by 10
   4. D. While she cries on the cot
   Show answer

   Answer: B. 30 to 60 seconds, while calm

   Infants normally breathe irregularly, with short pauses, so a brief count multiplied up can badly overestimate or underestimate the rate; count for at least 30 seconds (and double it) or a full minute, ideally while the infant is calm. A 15-second count times 4 multiplies any pause or burst fourfold. A 6-second count times 10 is even less reliable. Counting during crying measures agitation, not the resting rate. A pause of 20 seconds or more, or a shorter pause with color change or bradycardia, is apnea. (AHA PALS provider manual; Caroline 9th ed.)

2. When you hold a mask on an infant with the E-C clamp, the fingers forming the 'E' should rest on the:

   1. A. Bony ridge of the lower jaw
   2. B. Soft tissue under the chin
   3. C. Front of the neck at the larynx
   4. D. Cheeks just beside the nose
   Show answer

   Answer: A. Bony ridge of the lower jaw

   The fingers of the 'E' lift the bony mandible into the mask, which pulls the tongue forward and opens the airway. Pressing on the soft tissue under the chin pushes the tongue up against the palate and squeezes the soft infant airway closed. Pressure on the front of the neck compresses the pliable trachea. The cheeks give no grip for lifting the jaw and the mask leaks. (AHA PALS provider manual; Caroline 9th ed.)

3. When opening the airway of an unresponsive infant, overextending the neck can:

   1. A. Open the airway more fully
   2. B. Lift the epiglottis off the glottis
   3. C. Kink the soft trachea and block it
   4. D. Keep the tongue from falling back
   Show answer

   Answer: C. Kink the soft trachea and block it

   An infant's trachea is short, soft and easily compressed, so hyperextension can kink it and obstruct the airway; aim for a neutral (sniffing) position with padding under the shoulders if needed. Extension beyond neutral does not open it further. The epiglottis is not lifted by neck extension. The tongue is managed with a jaw thrust or an airway adjunct, and overextension does not reliably hold it forward. (AHA PALS provider manual; Caroline 9th ed.)

4. Compared with an adult's, a young child's larynx is positioned:

   1. A. Lower and more posterior
   2. B. Lower and more anterior
   3. C. At the same level as an adult's
   4. D. Higher and more anterior
   Show answer

   Answer: D. Higher and more anterior

   The child's larynx sits higher (about C3 to C4) and more anteriorly, which makes the glottis harder to see during laryngoscopy. It descends to the adult position with growth, so lower positions describe the adult, not the child.

5. A pink, well-perfused 4-month-old is asleep in her crib with a heart rate of 95 beats/min. This rate is best interpreted as:

   1. A. Bradycardia needing compressions
   2. B. A sign of rising intracranial pressure
   3. C. Normal for a sleeping infant
   4. D. A sign of hypoxia needing a BVM
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   Answer: C. Normal for a sleeping infant

   Heart rates fall during sleep; the PALS table gives about 100 to 180 beats/min for an awake infant and about 90 to 160 asleep, so 95 with good color and perfusion is normal (recheck once she wakes). Compressions are for a rate below 60 with poor perfusion despite oxygenation and ventilation. Bradycardia from raised intracranial pressure comes with altered responsiveness, irregular breathing and rising blood pressure. Hypoxic bradycardia comes with poor color and perfusion, which she does not have. (AHA PALS provider manual.)

6. Because an infant's chest wall is soft and compliant, increased work of breathing typically shows as:

   1. A. Intercostal and sternal retractions
   2. B. A barrel-shaped, hyperinflated chest wall
   3. C. Pursed-lip breathing on exhalation
   4. D. Tripod positioning with the arms braced
   Show answer

   Answer: A. Intercostal and sternal retractions

   The pliable chest wall is pulled inward when the infant generates high negative pressure, producing visible retractions. A barrel chest reflects chronic lung disease in adults, and pursed-lip breathing and tripod positioning are learned postures of older children and adults rather than the result of a soft chest wall.

7. A child's mediastinum is more mobile than an adult's. As a result, a tension pneumothorax in a child:

   1. A. Is prevented by flexible ribs
   2. B. Rarely affects venous return
   3. C. Cannot develop during BVM ventilation
   4. D. Shifts the heart and vessels sooner
   Show answer

   Answer: D. Shifts the heart and vessels sooner

   The mobile mediastinum swings easily toward the opposite side, kinking the great veins and cutting venous return, so a child with a tension pneumothorax can decompensate quickly. Flexible ribs transmit force to the lungs but do not prevent a pneumothorax. Reduced venous return is the central problem, not a rare one. Positive-pressure ventilation can create or worsen a tension pneumothorax. (ATLS 10th ed., pediatric trauma.)

8. The anterior fontanelle typically closes by about:

   1. A. About 6 weeks after birth
   2. B. 9 to 18 months of age
   3. C. 3 to 4 years of age
   4. D. 5 to 6 years of age
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   Answer: B. 9 to 18 months of age

   The anterior fontanelle usually closes between 9 and 18 months, so it can be assessed for bulging or sinking throughout infancy. The posterior fontanelle is the one that closes early, by about 2 to 4 months.

9. A toddler weighed 10.0 kg at a clinic visit last week and now weighs 9.4 kg after 2 days of diarrhea. This weight loss suggests:

   1. A. About 0.6%, too small to matter
   2. B. About 6%, moderate dehydration
   3. C. About 15%, severe dehydration
   4. D. About 60%, beyond survival
   Show answer

   Answer: B. About 6%, moderate dehydration

   Acute weight loss approximates fluid loss: 0.6 kg out of 10 kg is 6%, which falls in the moderate range (roughly 6% to 9%; mild is under about 5% and severe is 10% or more). A recent weight is the most objective estimate when available. 0.6% and 60% are decimal-place errors. 15% would require a loss of 1.5 kg. (CDC MMWR 2003 gastroenteritis guidance; Caroline 9th ed.)

10. In a house fire, young children absorb toxic gases such as carbon monoxide faster than adults mainly because they have:

    1. A. A larger total lung capacity
    2. B. Lower hemoglobin affinity for CO
    3. C. Slower breathing rates at rest
    4. D. Higher minute ventilation per kg
    Show answer

    Answer: D. Higher minute ventilation per kg

    Children breathe more air per kilogram each minute, so they take in more carbon monoxide and other toxic gases for their size and show toxicity sooner. Their total lung capacity is smaller, not larger. Fetal and infant hemoglobin binds CO at least as avidly as adult hemoglobin, not less. Children breathe faster, not slower, than adults. (Caroline 9th ed.; AHA PALS provider manual.)

11. Because a child's chest wall is thin, breath sounds carry across the chest. When you listen for a pneumothorax in a child, you should:

    1. A. Compare both sides in the axillae
    2. B. Listen over the upper sternum
    3. C. Trust breath sounds over vital signs
    4. D. Skip auscultation in children
    Show answer

    Answer: A. Compare both sides in the axillae

    Sounds from the good lung transmit across a small, thin chest and can mask a pneumothorax, so listen high in the axillae, compare sides, and correlate with chest rise, SpO2, ETCO2 and perfusion. The upper sternum mostly carries tracheal sounds. Breath sounds can mislead in children and should not outrank vital signs. Auscultation is still useful when done in the right places. (AHA PALS provider manual; Caroline 9th ed.)

12. An infant's cardiac output depends largely on heart rate because the infant:

    1. A. Cannot raise the heart rate above 160
    2. B. Has a much lower resting heart rate
    3. C. Cannot raise stroke volume very much
    4. D. Has a ventricle that stretches easily
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    Answer: C. Cannot raise stroke volume very much

    The small, less compliant infant ventricle cannot increase stroke volume much, so cardiac output rises mainly through tachycardia, and bradycardia sharply reduces it. The infant ventricle is stiff rather than easily stretched, and the resting heart rate is higher, not lower, than an adult's. Infants readily reach heart rates well above 160 when compensating.

13. Children maintain a normal blood pressure in early shock mainly through:

    1. A. Bradycardia and larger stroke volume
    2. B. Tachycardia and vasoconstriction
    3. C. Tachypnea and vasodilation
    4. D. Tachycardia and higher stroke volume
    Show answer

    Answer: B. Tachycardia and vasoconstriction

    Strong compensation through a fast heart rate and peripheral vasoconstriction keeps blood pressure normal until late, so hypotension in a child is an ominous sign. Children cannot raise stroke volume much, so the tachycardia, not a bigger stroke volume, carries cardiac output, and the vessels constrict rather than dilate. Bradycardia lowers output in children and signals decompensation rather than compensation.

14. A calm, afebrile 3-year-old has a resting heart rate of 165 beats/min. You should:

    1. A. Record it as a normal toddler rate
    2. B. Give adenosine for presumed SVT
    3. C. Ignore it unless BP is low
    4. D. Look for a cause such as shock
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    Answer: D. Look for a cause such as shock

    An awake toddler normally runs about 98 to 140 beats/min, so 165 at rest without fever is tachycardia; look for hypovolemia, sepsis, hypoxia, pain or a toxin. It is not normal for age. SVT in a child is usually above about 220 beats/min with a fixed rate, so 165 does not fit. Blood pressure falls late in children, and waiting for hypotension means treating shock late. (AHA PALS provider manual vital-sign tables.)

15. For an infant aged 1 to 12 months, hypotension is a systolic blood pressure below about:

    1. A. 50 mm Hg
    2. B. 90 mm Hg
    3. C. 70 mm Hg
    4. D. 100 mm Hg
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    Answer: C. 70 mm Hg

    PALS defines hypotension as a systolic pressure below 60 mm Hg in term neonates (0 to 28 days), below 70 mm Hg in infants 1 to 12 months, below 70 + (2 x age) for children 1 to 10 years, and below 90 mm Hg from age 10. 50 mm Hg is well below the threshold, so it would miss hypotension. 90 mm Hg is the threshold for children 10 and older. 100 mm Hg is a normal pressure, not a cutoff. (AHA PALS provider manual.)

16. A 12-year-old has a systolic blood pressure of 86 mm Hg after a bicycle crash. Using PALS limits, he is:

    1. A. Hypotensive for his age
    2. B. Normal for a school-age child
    3. C. Hypertensive for his age
    4. D. Normal once over age 10
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    Answer: A. Hypotensive for his age

    From age 10 the PALS hypotension threshold is a systolic pressure below 90 mm Hg, so 86 mm Hg is hypotension, a late and dangerous sign in an injured child. It is not normal for a school-age child. It is low, not high. Turning 10 raises the threshold to the adult-like 90 mm Hg; it does not make 86 acceptable. (AHA PALS provider manual.)

17. Which respiratory rate is normal for a resting 2-year-old?

    1. A. 12 breaths/min
    2. B. 50 breaths/min
    3. C. 30 breaths/min
    4. D. 60 breaths/min
    Show answer

    Answer: C. 30 breaths/min

    A toddler normally breathes about 22 to 37 times per minute. A rate of 12 breaths/min is normal for an adult but represents dangerous bradypnea in a 2-year-old.

18. A 9-month-old clings to her mother and screams when you approach, but she is pink and moving all extremities. This behavior is most consistent with:

    1. A. Early signs of hypoxia
    2. B. Normal stranger anxiety
    3. C. Meningeal irritation
    4. D. An altered mental status
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    Answer: B. Normal stranger anxiety

    Stranger anxiety normally begins around 6 to 9 months, and vigorous crying with good color reassures you about appearance. An infant with hypoxia or altered mental status is more often listless and poorly interactive.

19. The best way to assess a 9-month-old who is crying but alert is to:

    1. A. Separate her from the parent first
    2. B. Lay her on the cot by herself
    3. C. Start the exam at the face and head
    4. D. Examine her on the parent's lap
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    Answer: D. Examine her on the parent's lap

    Keeping the infant with the caregiver reduces fear and gives a calmer, more accurate assessment. Starting at the face is the most upsetting approach; infants and toddlers tolerate a trunk-first or toe-to-head exam better.

20. Before listening to the chest of an anxious 4-year-old, a useful way to gain his cooperation is to:

    1. A. Let him hold and try the stethoscope
    2. B. Hold him still while you listen
    3. C. Tell him he will get a shot if he cries
    4. D. Send the parent out to calm him
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    Answer: A. Let him hold and try the stethoscope

    Preschoolers fear what they do not understand; letting them touch and 'try' the equipment, or listen on a doll or parent first, turns it into play and gains cooperation. Holding him down increases fear and crying, which spoils the exam. Threats destroy trust and make later care harder. A caregiver's presence calms a young child, so sending the parent away backfires. (AAP pediatric pain and anxiety statement; Caroline 9th ed.)

21. A 14-year-old with a forearm fracture asks you not to cut off her shirt in front of her classmates. You should:

    1. A. Protect her privacy while you work
    2. B. Cut the shirt off right where she sits
    3. C. Have her remove the shirt herself
    4. D. Leave the shirt on and skip the arm exam
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    Answer: A. Protect her privacy while you work

    Adolescents are very sensitive about privacy, modesty and body image, so shield her from peers or move her to the ambulance before exposing the arm; a stable, isolated fracture allows this. Cutting the shirt off in front of classmates ignores a reasonable request without clinical need. Having her pull the shirt off herself moves the injured arm, and leaving the arm covered means the injury and distal circulation are never assessed. (Caroline 9th ed.)

22. While you start an IV on a frightened 6-year-old, the best nondrug way to reduce his pain and fear is:

    1. A. Saying the needle will not hurt
    2. B. Distraction with a video or game
    3. C. Asking the parent to leave the room
    4. D. Keeping him from watching anything
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    Answer: B. Distraction with a video or game

    Distraction (a video, game, bubbles or counting) is an evidence-based way to reduce procedural pain and anxiety in children and works well alongside honest preparation. Promising that it will not hurt destroys trust as soon as it does. Parent presence usually calms a child, so sending the parent out tends to make it worse. Blocking all activity removes a useful distraction rather than helping. (AAP, Relief of pain and anxiety in pediatric patients in EMS, 2012.)

23. A 5-year-old with abdominal pain lies very still and quiet and refuses to move. This behavior most likely means:

    1. A. His pain is probably mild
    2. B. He is simply tired and sleepy
    3. C. He may be in significant pain
    4. D. He is being uncooperative on purpose
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    Answer: C. He may be in significant pain

    Young children in severe pain, especially peritoneal pain, often lie still, quiet and guarded rather than crying, so use an age-appropriate pain scale and look for the cause. Quiet behavior does not mean mild pain. Tiredness does not explain refusing to move. Labeling the behavior as defiance leads to undertreated pain and a missed diagnosis. (AAP pediatric pain statement; Caroline 9th ed.)

24. Since 2020, the leading cause of death in US children and adolescents aged 1 to 19 years has been:

    1. A. Motor vehicle crashes
    2. B. Drowning
    3. C. Childhood cancers
    4. D. Firearm injuries
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    Answer: D. Firearm injuries

    CDC mortality data show firearm injuries (homicide, suicide and unintentional) overtook motor vehicle crashes in 2020 as the leading cause of death for ages 1 to 19 and stayed first through at least 2022 and 2023. Motor vehicle crashes are now second. Drowning leads among children 1 to 4 years but not across the whole 1-to-19 range. Cancer is the leading disease-related cause, not the leading cause overall. (Goldstick et al., NEJM 2022; AAP firearm policy statement 2022.)

25. Even slight swelling of the airway lining sharply narrows an infant's airway because:

    1. A. Infant airway cartilage is already calcified
    2. B. The trachea is longer than an adult's
    3. C. The larynx sits lower in the neck
    4. D. Its small diameter magnifies resistance
    Show answer

    Answer: D. Its small diameter magnifies resistance

    Resistance rises dramatically as airway radius shrinks, so 1 mm of edema in a tiny infant airway causes far more obstruction than in an adult. Infant airway cartilage is soft and the larynx is high, not calcified or low.