Airway Anatomy and Physiology Practice Questions

32 multiple-choice questions on Airway anatomy and physiology for paramedic and EMT students, from Chapter 16 (Airway Management). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

32 practice questions

1. A cuffed 4.5-mm tube passes a 3-year-old's vocal cords easily but meets firm resistance just below them. What is the best response?

   1. A. Twist and push it past the resistance
   2. B. Inflate the cuff to stretch the area
   3. C. Leave the tip above the cords and bag
   4. D. Change to a tube a half size smaller
   Show answer

   Answer: D. Change to a tube a half size smaller

   In young children the subglottic (cricoid) region is a functional narrow point, so a tube that clears the cords can still be too large below them. Swap to a tube a half size smaller. Twisting or pushing through tears the mucosa and leads to subglottic edema or stenosis. Inflating a cuff inside the narrowing adds pressure injury and does not dilate it. A tip left above the cords is not in the trachea and will dislodge or ventilate the stomach.

2. While inserting a lubricated nasopharyngeal airway, you aim the tip upward toward the eye and meet resistance. What should you do?

   1. A. Push firmly through the point of resistance
   2. B. Aim it further upward and rotate
   3. C. Aim it straight back along the floor
   4. D. Switch to a longer nasal airway
   Show answer

   Answer: C. Aim it straight back along the floor

   The nasal passage runs straight back along its floor, parallel to the hard palate, not upward. Aiming up drives the tip into the turbinates, which bleed easily. Pushing harder or aiming further up adds trauma (and near the cribriform plate, more risk). A longer airway does not fix the wrong direction. Redirect along the floor, and if it still resists, try the other nostril.

3. You tilt a 9-month-old's head far back to open her airway, and chest rise during bag-mask breaths gets worse. What is the most likely reason?

   1. A. Her soft trachea kinks or compresses
   2. B. Her tongue falls further into the pharynx
   3. C. Her epiglottis lifts clear of the glottis
   4. D. Her larynx drops lower in the neck
   Show answer

   Answer: A. Her soft trachea kinks or compresses

   An infant's trachea is soft and short, so hyperextension can kink or compress it and worsen obstruction. Infants do best in a neutral (sniffing-neutral) position. Extension pulls the tongue forward rather than back. Lifting the epiglottis clear would open, not close, the airway. Head position does not move the larynx lower; the infant larynx sits high.

4. On an obese neck you cannot feel the thyroid prominence. Which approach best locates the cricothyroid membrane?

   1. A. Feel just below the hyoid bone
   2. B. Go one fingerbreadth below the cricoid ring
   3. C. Feel up from the sternal notch to the cricoid
   4. D. Pick the deepest skin crease on the front of the neck
   Show answer

   Answer: C. Feel up from the sternal notch to the cricoid

   When the thyroid prominence is hidden, find the trachea above the sternal notch and walk upward to the first firm ring that stands out, the cricoid; the membrane lies just above it. The space below the hyoid is the thyrohyoid membrane, which is above the vocal cords. Below the cricoid lies the trachea and thyroid isthmus. Skin creases on an obese neck do not mark the larynx; if landmarks stay unclear, a vertical skin incision lets you find it by touch.

5. You insert a curved blade in the midline, and the tongue bulges over both sides of the blade and blocks your view. What was the technique error?

   1. A. Holding the laryngoscope handle in the left hand
   2. B. Not hyperextending the neck fully
   3. C. Choosing a blade that was too long
   4. D. Not entering on the right and sweeping left
   Show answer

   Answer: D. Not entering on the right and sweeping left

   A Macintosh blade enters at the right side of the mouth and sweeps the tongue to the left into the blade's flange, which clears the line of sight. Entering midline leaves tongue on both sides. The laryngoscope is correctly held in the left hand. Full neck hyperextension is not the goal; the sniffing or ramped position is. A long blade can go too deep, but it would not make the tongue bulge over both sides.

6. During laryngoscopy of an infant, the glottis seems to sit 'anterior' and is hard to bring into view. What anatomic feature mainly explains this?

   1. A. The trachea is longer than an adult's
   2. B. The epiglottis is short and stiff
   3. C. The tongue is small for the mouth
   4. D. The larynx sits higher in the neck
   Show answer

   Answer: D. The larynx sits higher in the neck

   An infant's larynx lies higher (about C2-C4 versus C4-C6 in adults), so it appears anterior, which is one reason a straight blade and slight neutral positioning help. The infant trachea is short, not long. The infant epiglottis is long and floppy, not short and stiff. The tongue is large relative to the mouth, not small.

7. At approximately what surface landmark does the carina lie in an adult?

   1. A. The suprasternal notch
   2. B. The sternal angle
   3. C. The xiphoid process
   4. D. The cricoid cartilage
   Show answer

   Answer: B. The sternal angle

   The carina lies at about the level of the sternal angle (angle of Louis), roughly T4 to T5.

8. A patient in acute pulmonary edema has an SpO2 of 84%, but his EtCO2 is 32 mmHg. Why is CO2 not elevated while oxygen is so low?

   1. A. Edema fluid absorbs CO2 from the blood
   2. B. Hypoxia slows the body's CO2 production
   3. C. The capnograph reads falsely low in pulmonary edema
   4. D. CO2 crosses the fluid barrier far more easily
   Show answer

   Answer: D. CO2 crosses the fluid barrier far more easily

   Carbon dioxide is about 20 times more diffusible than oxygen, so a thickened, fluid-filled membrane limits oxygen uptake first, and the fast breathing of distress blows off CO2. A rising EtCO2 in this patient would signal tiring. Edema fluid does not act as a CO2 sink. Hypoxia does not meaningfully cut CO2 production. The capnograph is not falsely low; it reflects real ventilation.

9. A submersion victim has crackles and an SpO2 of 85% despite good bag-mask breaths with 100% oxygen. Which addition is most likely to improve oxygenation?

   1. A. A faster bagging rate of 30 per minute
   2. B. A PEEP valve on the bag-valve mask
   3. C. Larger, more forceful breaths
   4. D. Abdominal thrusts to drain water
   Show answer

   Answer: B. A PEEP valve on the bag-valve mask

   Aspirated water washes out surfactant, so alveoli collapse and blood shunts past them. PEEP (about 5 to 10 cmH2O) keeps those alveoli open and improves oxygenation. A faster rate does not reopen collapsed alveoli and adds gastric inflation. Forceful breaths raise barotrauma and gastric risk. Abdominal thrusts are not recommended in drowning; they delay ventilation and cause vomiting.

10. You are bagging an intubated overdose patient at 30 breaths per minute. He had weak breaths of his own, but they stop, and his EtCO2 is 24 mmHg. What is the most likely explanation?

    1. A. His opioid level is climbing again
    2. B. Your rate has removed his CO2 drive to breathe
    3. C. The tube has slipped into the esophagus
    4. D. He has developed a tension pneumothorax from bagging
    Show answer

    Answer: B. Your rate has removed his CO2 drive to breathe

    Rising CO2 is the main stimulus to breathe. Bagging at 30 per minute drives EtCO2 down to 24, so his own effort stops. Slow to about 1 breath every 6 seconds and aim for a normal EtCO2. A rising opioid level would not explain a low CO2. An esophageal tube would show no waveform, not a reading of 24. A tension pneumothorax causes rising airway pressure, hypotension, and falling SpO2, not apnea from low CO2.

11. A man with significant carbon monoxide poisoning is breathing at a normal rate. Why don't his peripheral chemoreceptors drive faster breathing?

    1. A. CO directly depresses the medulla
    2. B. Carboxyhemoglobin lowers his CO2
    3. C. They respond to the SpO2 rather than the PaO2
    4. D. They sense PaO2, which stays near normal
    Show answer

    Answer: D. They sense PaO2, which stays near normal

    The carotid and aortic bodies respond to the partial pressure of dissolved oxygen (PaO2), which stays near normal in CO poisoning even though oxygen content is low. So there is little drive to breathe faster despite tissue hypoxia. CO does not primarily depress the medulla at this stage. Carboxyhemoglobin does not lower CO2. The receptors do not read saturation; they read PaO2.

12. A patient has a tidal volume of 500 mL, a respiratory rate of 12, and an anatomic dead space of 150 mL. What is the alveolar minute volume?

    1. A. 5,400 mL/min
    2. B. 3,600 mL/min
    3. C. 6,000 mL/min
    4. D. 4,200 mL/min
    Show answer

    Answer: D. 4,200 mL/min

    Alveolar minute volume = (tidal volume - dead space) x rate = (500 - 150) x 12 = 4,200 mL/min. 6,000 mL/min is total minute volume.

13. A patient breathes 20 times per minute with a tidal volume of 400 mL. What is the minute volume?

    1. A. 5,000 mL
    2. B. 4,200 mL
    3. C. 8,000 mL
    4. D. 10,000 mL
    Show answer

    Answer: C. 8,000 mL

    Minute volume = tidal volume x respiratory rate = 400 x 20 = 8,000 mL per minute.

14. You add a 15-cm extension and a filter between a 10-kg infant's ET tube and the bag. EtCO2 then climbs steadily despite the same rate. Why?

    1. A. The extra equipment adds dead space
    2. B. The filter lowers the delivered oxygen
    3. C. The extension raises airway resistance
    4. D. The infant's metabolism has sped up
    Show answer

    Answer: A. The extra equipment adds dead space

    A 10-kg infant's tidal volume is only about 60 to 80 mL, so tubing and a filter between the tube and the bag can add a large share of rebreathed dead space, and CO2 rises. Remove unneeded attachments. A filter does not lower FiO2. Added length barely changes resistance at these flows and would not by itself raise CO2. Nothing in the scenario suggests a metabolic change.

15. A patient with severe right lower lobe pneumonia must ride on his side during transport. Which position will most likely improve his oxygenation?

    1. A. Right side down, diseased lung lowest
    2. B. Prone with the head turned to the left
    3. C. Left side down, healthy lung lowest
    4. D. Flat on the back with legs raised
    Show answer

    Answer: C. Left side down, healthy lung lowest

    Gravity sends more blood to the lower lung. With the healthy left lung down, more blood flows past ventilated alveoli and V/Q matching improves ('good lung down'). Putting the diseased right lung down sends more blood past consolidated alveoli and worsens shunt. Prone positioning is not a field option for a transport like this. Supine with legs raised does not improve matching and may worsen breathing.

16. During an intubation attempt the finger probe still shows an SpO2 of 94%, though the patient has been apneic for some time. Why can it lag?

    1. A. Pulse oximeters average over about 5 minutes
    2. B. Apnea increases blood flow to the fingers
    3. C. The probe is counting carboxyhemoglobin
    4. D. Finger readings lag behind the lungs
    Show answer

    Answer: D. Finger readings lag behind the lungs

    Blood takes time to travel from the lungs to a finger, and the lag is longer with poor perfusion, so a finger SpO2 can still look normal while the arterial level is already falling. Watch the time and stop early; ear or forehead sites respond faster. Oximeters average over a few seconds, not minutes. Apnea does not raise finger blood flow. There is no reason here to suspect carboxyhemoglobin from carbon monoxide.

17. A patient with a total laryngectomy has thick, crusted secretions at his neck stoma during a long transport. Why is this common?

    1. A. The stoma lining produces more mucus than the nose
    2. B. Oxygen thickens airway secretions
    3. C. Inhaled air bypasses the nose's humidification
    4. D. Laryngectomy weakens the cough muscles
    Show answer

    Answer: C. Inhaled air bypasses the nose's humidification

    The nose warms, filters, and humidifies air. A neck breather inhales directly into the trachea, so secretions dry and crust. Use humidified oxygen or a moist stoma cover, and suction gently. The stoma lining does not make more mucus than the nose. Dry oxygen makes it worse, but oxygen itself does not thicken mucus. Cough strength comes from the chest and abdomen; it is the loss of the closed glottis, not weak muscles, that changes coughing.

18. A patient with COPD breathes out slowly through pursed lips. How does this help him?

    1. A. It slows CO2 loss to keep up his drive
    2. B. It splints his small airways open
    3. C. It filters dry air before he breathes in
    4. D. It strengthens his diaphragm over time
    Show answer

    Answer: B. It splints his small airways open

    Exhaling against pursed lips creates back pressure that keeps floppy small airways from collapsing, so more trapped air empties and work of breathing falls. It is not done to hold CO2 for respiratory drive. It happens on exhalation and filters nothing on the way in, so it does not filter dry air. It is a breathing pattern, not a training exercise for the diaphragm.

19. A transport ventilator is set with an inspiratory-to-expiratory (I:E) ratio of about 1:2. Why is exhalation given more time?

    1. A. Inspiration needs time to fill the bag
    2. B. A long exhalation raises the FiO2
    3. C. It prevents air from entering the stomach
    4. D. Exhalation is passive and takes longer
    Show answer

    Answer: D. Exhalation is passive and takes longer

    Exhalation depends on the passive recoil of the lungs and chest wall, so it needs more time than the pushed inspiration. In bronchospasm it needs even longer (1:3 or 1:4) to avoid air trapping. Bag refill has nothing to do with the patient's I:E ratio. Exhalation time does not change FiO2. Air entering the stomach is limited by low inspiratory pressure, not by exhalation time.

20. As the diaphragm contracts during spontaneous inspiration, intrathoracic pressure:

    1. A. Falls below atmospheric
    2. B. Rises above atmospheric
    3. C. Stays equal to atmospheric
    4. D. Rises, then equalizes
    Show answer

    Answer: A. Falls below atmospheric

    Contraction expands the thoracic cavity, dropping intrathoracic pressure below atmospheric so air flows in. Positive-pressure ventilation reverses this.

21. You begin bag-mask ventilation on a hypotensive patient and bag rapidly and forcefully. The blood pressure drops further. What is the most likely mechanism?

    1. A. Reduced venous return
    2. B. Vagal reflex from the mask
    3. C. Increased afterload
    4. D. Increased cardiac preload
    Show answer

    Answer: A. Reduced venous return

    Positive pressure raises intrathoracic pressure, which impedes venous return and lowers cardiac output. Excessive rate and volume make this worse.

22. A term newborn is crying with a heart rate of 140, and her preductal SpO2 is 72% at 3 minutes of age on room air. What is appropriate?

    1. A. Routine care; this is expected
    2. B. Start positive-pressure ventilation
    3. C. Give 100% oxygen to reach 95%
    4. D. Suction her trachea deeply
    Show answer

    Answer: A. Routine care; this is expected

    SpO2 rises slowly after birth. NRP targets are about 70% to 75% at 3 minutes and 85% to 95% by 10 minutes, so 72% in a crying baby with a good heart rate is expected. Positive-pressure ventilation is for apnea, gasping, or a heart rate below 100. Pushing oxygen to 95% this early causes hyperoxia. Deep suctioning is not routine and can cause bradycardia.

23. In an intubated patient in shock, the EtCO2 reads 28 mmHg while the arterial PaCO2 is 45 mmHg. What best explains the gap?

    1. A. Shock raises CO2 production sharply
    2. B. The capnograph reads high in shock
    3. C. Acidosis turns CO2 into bicarbonate
    4. D. Low lung blood flow widens the gap
    Show answer

    Answer: D. Low lung blood flow widens the gap

    EtCO2 normally runs only a few mmHg below PaCO2. When lung perfusion falls, ventilated alveoli with little blood flow dilute the exhaled CO2, so EtCO2 underestimates PaCO2. Do not hyperventilate to a 'normal' EtCO2 in shock. CO2 production does not rise sharply; it usually falls. The capnograph does not read high; the gap goes the other way. Acidosis and bicarbonate buffering do not make EtCO2 lower than PaCO2.

24. Why does gastric distension during bag-mask ventilation compromise breathing more in an infant than in an adult?

    1. A. Infant stomachs empty much faster
    2. B. Infants rely mainly on the diaphragm
    3. C. Infant chest walls are very stiff
    4. D. Infant lungs hold more air per kilogram
    Show answer

    Answer: B. Infants rely mainly on the diaphragm

    Infants breathe mostly with the diaphragm because their horizontal ribs and weak intercostals add little, so a distended stomach pushing up on the diaphragm quickly limits ventilation. Faster gastric emptying would help, not hurt. The infant chest wall is soft and compliant, not stiff. Infant lungs do not hold more air per kilogram; their reserve is small.

25. A woman at 36 weeks' gestation is resting comfortably with an EtCO2 of 30 mmHg. How should you interpret this?

    1. A. Early respiratory failure is developing
    2. B. The uterus is causing hypoventilation
    3. C. It is normal for late pregnancy
    4. D. The capnograph needs recalibration
    Show answer

    Answer: C. It is normal for late pregnancy

    Progesterone raises minute ventilation in pregnancy, so a resting PaCO2 and EtCO2 around 28 to 32 mmHg are normal. A 'normal' 40 mmHg can mean she is tiring. Respiratory failure would raise CO2, not lower it. The uterus reduces FRC but does not cause hypoventilation; CO2 runs low, not high. Nothing suggests the capnograph needs recalibration.

26. A 180-cm (5 ft 11 in), 130-kg man is placed on a transport ventilator. Using 6 to 8 mL/kg of ideal body weight (about 75 kg), which tidal volume range fits?

    1. A. About 780 to 1,040 mL
    2. B. About 450 to 600 mL
    3. C. About 225 to 300 mL
    4. D. About 900 to 1,200 mL
    Show answer

    Answer: B. About 450 to 600 mL

    Lung size follows height, not weight. Ideal body weight here is about 75 kg (50 + 2.3 x 11 inches), so 6 to 8 mL/kg gives about 450 to 600 mL. 780 to 1,040 mL uses his actual 130 kg and overdistends the lungs. 225 to 300 mL is 3 to 4 mL/kg, too small. 900 to 1,200 mL is 12 to 16 mL/kg, an old and harmful range.

27. Bag-mask ventilation becomes very stiff in a patient with severe pulmonary edema. What best explains the stiffness?

    1. A. The bag's one-way valve is sticking shut
    2. B. Pulmonary edema widens the airways
    3. C. Fluid-filled lungs have low compliance
    4. D. The stomach is filling with fluid
    Show answer

    Answer: C. Fluid-filled lungs have low compliance

    Fluid in the alveoli and interstitium makes the lungs stiff (low compliance), so more pressure is needed for each breath; PEEP or CPAP helps. A sticking valve is possible but is not the best explanation in this setting. Edema narrows rather than widens airways. Fluid does not fill the stomach in pulmonary edema; air from high-pressure bagging might.

28. A hypercapnic COPD patient on a nonrebreather becomes drowsy as his CO2 rises. Which mechanism explains most of the CO2 rise?

    1. A. Oxygen being converted to CO2 in the lungs
    2. B. Worse V/Q matching and the Haldane effect
    3. C. More CO2 made by his breathing muscles
    4. D. Suppression of a hypoxic drive by itself
    Show answer

    Answer: B. Worse V/Q matching and the Haldane effect

    High oxygen releases hypoxic vasoconstriction, so blood flows to poorly ventilated areas, and oxygenated hemoglobin carries less CO2 (Haldane effect). Together these explain most of the rise; loss of hypoxic drive plays a smaller part. Oxygen is not converted to CO2 in the lungs. CO2 made by the breathing muscles does not explain drowsiness after oxygen. The practical answer is the same: titrate to 88% to 92%.

29. Why does 1 mm of airway swelling cause much more distress in an infant than in an adult?

    1. A. Infant mucosa swells less than adult mucosa does
    2. B. Infant tracheas are more rigid than adults'
    3. C. Resistance rises steeply as the radius falls
    4. D. Infants breathe more slowly than adults
    Show answer

    Answer: C. Resistance rises steeply as the radius falls

    Airway resistance rises roughly with the fourth power of a falling radius, so 1 mm of edema in a 4-mm infant airway raises resistance many times more than in a 20-mm adult airway. Infant mucosa swells easily, not less. The infant trachea is soft, not rigid. Infants breathe faster, not more slowly.

30. Why can a small head movement easily dislodge an infant's endotracheal tube?

    1. A. The infant tongue pushes it out
    2. B. The infant neck is stiff and fixed
    3. C. The infant vocal cords are wider
    4. D. The infant trachea is very short
    Show answer

    Answer: D. The infant trachea is very short

    An infant's trachea is only about 4 to 5 cm long, so a little flexion or extension moves the tip into a bronchus or out through the cords. Secure the tube, note the depth, and recheck after every move. The infant neck is mobile, not stiff. The infant glottis is small, not wide. The tongue does not push a secured tube out; the depth changes because head movement acts on a very short trachea.

31. Why is a nasopharyngeal airway more likely to cause heavy bleeding in a 6-year-old than in an adult?

    1. A. Children's blood clots more slowly
    2. B. Large adenoid tissue lines the nasopharynx
    3. C. Children have no nasal turbinates
    4. D. The nasal floor slopes steeply upward in children
    Show answer

    Answer: B. Large adenoid tissue lines the nasopharynx

    Children have prominent adenoids in the nasopharynx that bleed easily when scraped, so NPAs are used with care and a well-lubricated, correctly sized device. Children's clotting is normal. Children do have turbinates. The nasal floor runs straight back in children too.

32. A trauma patient with a small pneumothorax now needs bag-mask ventilation. What must you watch for?

    1. A. Progression to a tension pneumothorax
    2. B. Faster resolution of the air leak
    3. C. A falling airway pressure on bagging
    4. D. Better venous return with each breath
    Show answer

    Answer: A. Progression to a tension pneumothorax

    Positive pressure can push more air through the lung injury into the pleural space, turning a small pneumothorax into a tension pneumothorax. Watch for rising bag resistance, falling SpO2, hypotension, and absent breath sounds on one side. Positive pressure does not speed healing of the leak. Airway pressure rises, not falls. Venous return falls with positive pressure and tension.