Inhalation Injury and Smoke Exposure Practice Questions

25 multiple-choice questions on Inhalation injury and smoke exposure for paramedic and EMT students, from Chapter 33 (Burns). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. Thermal injury from breathing hot dry air is usually limited to the area above the vocal cords because:

   1. A. Hot air cannot pass the epiglottis
   2. B. The upper airway absorbs the heat
   3. C. The lungs are cooled by high blood flow
   4. D. Smoke particles block the upper trachea
   Show answer

   Answer: B. The upper airway absorbs the heat

   The moist mucosa of the nose, mouth, and pharynx dissipates heat before it reaches the glottis. Reflex laryngospasm also helps, but the epiglottis does not fully block airflow.

2. Superheated steam is more likely than hot dry air to burn the airway below the glottis because steam:

   1. A. Carries far more heat energy
   2. B. Is too cold to trigger laryngospasm
   3. C. Contains toxic combustion gases
   4. D. Is absorbed directly into blood
   Show answer

   Answer: A. Carries far more heat energy

   Water vapor holds many times more heat than dry air and releases it as it condenses deep in the airway. It is not a toxic gas.

3. Injury to the lower airways and alveoli in smoke inhalation is caused mainly by:

   1. A. Heat from the flames
   2. B. Particles of burned skin
   3. C. Oxygen deprivation alone
   4. D. Toxic smoke chemicals
   Show answer

   Answer: D. Toxic smoke chemicals

   Irritant gases and soot cause chemical injury below the glottis. Heat rarely reaches the lungs, except with steam.

4. The three broad categories of inhalation injury are:

   1. A. Thermal, chemical, and electrical
   2. B. Thermal, toxic, and mechanical
   3. C. Acute, chronic, and recurrent
   4. D. Thermal, chemical, and systemic
   Show answer

   Answer: D. Thermal, chemical, and systemic

   Thermal injury affects the upper airway, chemical irritants affect the lower airway, and asphyxiants such as CO and cyanide cause systemic toxicity. Electrical and mechanical injury are not categories of inhalation injury, and inhalation injury is not classified by its time course.

5. Which history most strongly suggests inhalation injury?

   1. A. Burn in an enclosed space
   2. B. Burn from a hot stove top
   3. C. Scald from spilled coffee
   4. D. Sunburn after a day at the beach
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   Answer: A. Burn in an enclosed space

   Being trapped in a closed space with smoke greatly raises the risk of inhaling heat and toxins. Contact burns and scalds rarely involve the airway.

6. A smoke inhalation victim is hypotensive and confused. His SpO2 reads 99% on oxygen. Regarding cyanide toxicity, this reading:

   1. A. Makes cyanide toxicity unlikely
   2. B. Does not rule it out
   3. C. Confirms good tissue oxygenation
   4. D. Shows his CO level is normal
   Show answer

   Answer: B. Does not rule it out

   Cyanide blocks the cells' use of oxygen; hemoglobin can still be fully saturated, so pulse oximetry may be normal. Carbon monoxide also falsely raises standard SpO2 readings. A normal reading does not make cyanide unlikely, does not show that tissues are using oxygen, and cannot show the CO level.

7. A burned patient has a mildly hoarse voice but is breathing comfortably, and the decision is made to transport without intubation. During the 40-minute trip you should:

   1. A. Check the airway only on hospital arrival
   2. B. Lay her flat to keep the airway open
   3. C. Reassess the airway often; be ready
   4. D. Give fluids rapidly to reduce the swelling
   Show answer

   Answer: C. Reassess the airway often; be ready

   Airway edema can progress over hours, so voice, stridor, drooling, and work of breathing must be rechecked frequently, with intubation equipment ready. Keeping the head elevated (if no spinal concern) helps limit swelling. Large fluid volumes worsen edema, and waiting until arrival risks a lost airway.

8. An intubated smoke inhalation patient develops rising ventilation pressures and falling SpO2. The tube is in place and breath sounds are equal. A likely cause is:

   1. A. A right mainstem intubation
   2. B. Too little oxygen left in the tank
   3. C. Soot and mucus blocking the tube
   4. D. Esophageal placement of the tube
   Show answer

   Answer: C. Soot and mucus blocking the tube

   Inhalation injury causes thick secretions, sloughed lining, and soot that can plug the endotracheal tube and bronchi. Suction the tube, check for obstruction with DOPE (displacement, obstruction, pneumothorax, equipment), and ventilate carefully. Equal breath sounds with the tube confirmed in place argue against mainstem or esophageal placement, and an empty tank would not raise pressures.

9. Airway swelling after an inhalation injury typically:

   1. A. Peaks within the first 10 minutes
   2. B. Worsens over the first 24 hours
   3. C. Resolves within 1 hour
   4. D. Is prevented by oxygen therapy
   Show answer

   Answer: B. Worsens over the first 24 hours

   Edema increases over hours and is worsened by fluid resuscitation. A patient who looks fine at first can obstruct later, which is why serial reassessment is essential.

10. You are preparing to intubate a 70-kg man with an inhalation injury. The endotracheal tube should ideally be:

    1. A. As small as possible, 5.0 mm or less
    2. B. Placed nasally for comfort
    3. C. Uncuffed to protect the trachea
    4. D. As large as possible, 7.5 mm or more
    Show answer

    Answer: D. As large as possible, 7.5 mm or more

    A large tube allows bronchoscopy and clearing of thick soot and secretions. In practice, swelling may force a smaller tube, so have several sizes and a surgical airway kit ready.

11. Before intubating a patient with an airway burn, you should be prepared for:

    1. A. A difficult airway and surgical backup
    2. B. A routine airway with good views
    3. C. Spontaneous resolution of swelling
    4. D. Easy bag-mask ventilation every time
    Show answer

    Answer: A. A difficult airway and surgical backup

    Edema distorts landmarks and narrows the glottis. The most experienced provider should intubate, with backup devices and cricothyrotomy equipment ready.

12. You have intubated a man with burned, weeping skin across his face. The tube is best secured with:

    1. A. Adhesive tape on the cheeks
    2. B. Cloth ties or a tube holder
    3. C. Sutures through the lips
    4. D. No device, holding it by hand
    Show answer

    Answer: B. Cloth ties or a tube holder

    Tape will not stick to burned, weeping skin, and tube loss in a swollen airway can be fatal. Ties must be checked as facial swelling increases.

13. A 40-year-old man with 50% TBSA burns from 3 hours ago needs rapid sequence intubation. Regarding succinylcholine:

    1. A. It can be used, since the burn is recent
    2. B. It is contraindicated after any burn
    3. C. It is safe only after 72 hours have passed
    4. D. It is safe only with full-thickness burns
    Show answer

    Answer: A. It can be used, since the burn is recent

    Hyperkalemia risk from upregulated acetylcholine receptors develops after the first day or two and lasts for months. In the first 24 hours after the burn, succinylcholine can be used.

14. Not every patient with facial burns needs intubation. Which patient is the best candidate for close observation without immediate intubation?

    1. A. Stridor and drooling after the fire
    2. B. Hoarseness with deep facial burns
    3. C. Unresponsive with a GCS of 6
    4. D. Singed eyebrows, clear voice
    Show answer

    Answer: D. Singed eyebrows, clear voice

    Isolated singed hair with a normal voice and no distress warrants monitoring, oxygen, and burn center evaluation. Unnecessary intubation carries real risks, but stridor, hoarseness with deep burns, or a GCS of 6 needs a definitive airway.

15. A firefighter who inhaled smoke is wheezing and short of breath 20 minutes after the fire. Besides high-flow oxygen, you should give:

    1. A. IV furosemide
    2. B. IM epinephrine 1 mg
    3. C. Inhaled albuterol
    4. D. Oral antihistamines
    Show answer

    Answer: C. Inhaled albuterol

    Smoke irritants cause bronchospasm that responds to bronchodilators. Epinephrine is for anaphylaxis, and the 1 mg IM dose would be dangerous.

16. A patient with smoke inhalation who seems well at the scene may develop pulmonary edema and ARDS:

    1. A. Hours to days later
    2. B. Within the first 15 minutes
    3. C. After about 1 to 2 weeks
    4. D. Once the burns begin to heal
    Show answer

    Answer: A. Hours to days later

    Chemical injury to the lower airway evolves over 12 to 36 hours or more. Patients with a significant smoke exposure should be evaluated even if they look well. Lung injury does not appear within minutes or wait until the burns heal or weeks have passed.

17. A 70-year-old with severe COPD was pulled from a smoky house. He is confused, and CO exposure is likely. Regarding oxygen, you should:

    1. A. Give 2 L/min to protect his breathing drive
    2. B. Withhold oxygen until his SpCO is known
    3. C. Give oxygen only if his SpO2 is below 88%
    4. D. Give high-flow oxygen despite his COPD
    Show answer

    Answer: D. Give high-flow oxygen despite his COPD

    Suspected CO poisoning calls for the highest oxygen concentration available, because oxygen speeds CO elimination and SpO2 readings are falsely high. Concern about hypercapnia in COPD does not justify withholding it; monitor ventilation and assist if needed. Low-flow oxygen or SpO2-guided titration undertreats CO.

18. In a burn patient pulled from a house fire, the best field tool to detect carbon monoxide exposure is:

    1. A. A standard pulse oximeter
    2. B. A CO-oximeter reading SpCO
    3. C. Capnography waveform shape
    4. D. Checking for cherry-red skin
    Show answer

    Answer: B. A CO-oximeter reading SpCO

    A CO-oximeter distinguishes carboxyhemoglobin from oxyhemoglobin. Cherry-red skin is a late, unreliable sign, and standard oximetry reads carboxyhemoglobin as oxygenated hemoglobin.

19. In a structure fire, hydrogen cyanide is produced mainly by burning:

    1. A. Clean, dry hardwood
    2. B. Paper and cardboard only
    3. C. Nylon, foam, wool, and silk
    4. D. Natural gas in a home furnace
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    Answer: C. Nylon, foam, wool, and silk

    Nitrogen-containing materials such as polyurethane foam, nylon, wool, and silk release cyanide. Gas furnaces are a classic source of CO, not cyanide.

20. In a smoke inhalation victim, which finding most strongly suggests significant cyanide toxicity?

    1. A. Severe lactic acidosis and hypotension
    2. B. A cherry-red color of the lips and face
    3. C. Mild headache with nausea only
    4. D. Soot in the mouth with a hacking cough
    Show answer

    Answer: A. Severe lactic acidosis and hypotension

    Cyanide halts aerobic metabolism, so a markedly high lactate (about 8 mmol/L or more) with hypotension, altered mental status, or seizures is the strongest marker of serious cyanide toxicity in fire victims. Cherry-red color is rare and unreliable, mild headache fits mild CO exposure, and soot shows smoke exposure but not cyanide severity.

21. In smoke inhalation victims, sodium nitrite is avoided as a cyanide antidote because it:

    1. A. Is not effective against cyanide
    2. B. Adds methemoglobin to CO hypoxia
    3. C. Causes severe rebound hypertension
    4. D. Must be given by inhalation only
    Show answer

    Answer: B. Adds methemoglobin to CO hypoxia

    Nitrites induce methemoglobin to bind cyanide, but a smoke victim already has carboxyhemoglobin, so oxygen delivery falls further. Hydroxocobalamin binds cyanide directly without this problem.

22. You are giving hydroxocobalamin to a smoke inhalation victim who also needs diazepam for seizures. Regarding IV lines, you should:

    1. A. Mix the diazepam into the antidote bag
    2. B. Push the diazepam into the same tubing
    3. C. Stop the antidote to give the diazepam
    4. D. Give the antidote through its own line
    Show answer

    Answer: D. Give the antidote through its own line

    Hydroxocobalamin is physically or chemically incompatible with many drugs (including diazepam, dopamine, and some others), so the manufacturer recommends a separate IV line. Mixing or pushing through the same tubing risks precipitation, and interrupting the antidote delays treatment of cyanide toxicity.

23. A 60-year-old man was rescued from a smoky bedroom. He is alert with no burns, normal vital signs, and a clear voice, but an SpCO of 22%. The most appropriate care is:

    1. A. Release after 10 minutes of oxygen
    2. B. Immediate intubation for airway burns
    3. C. High-flow oxygen and transport
    4. D. Hydroxocobalamin as the first step
    Show answer

    Answer: C. High-flow oxygen and transport

    He has significant CO exposure that needs high-flow oxygen and hospital evaluation, possibly for hyperbaric therapy. With a clear voice and no burns, he does not need airway intubation.

24. During fluid resuscitation of a patient with a known inhalation injury, you should anticipate that:

    1. A. Fluids will shrink airway edema
    2. B. Airway edema can worsen with fluids
    3. C. Fluid needs are lower than the formula
    4. D. Fluids should be cut to half the formula
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    Answer: B. Airway edema can worsen with fluids

    Resuscitation fluid adds to airway and lung edema, so the airway must be watched closely. Inhalation injury tends to increase, not decrease, fluid needs, so fluids are titrated to urine output rather than cut below the formula.

25. A child pulled from a house fire is drooling and refuses to swallow, with a muffled voice. These signs suggest:

    1. A. Normal anxiety after a frightening fire
    2. B. A swallowed foreign body in the esophagus
    3. C. Simple dehydration from the heat exposure
    4. D. Supraglottic swelling from a thermal burn
    Show answer

    Answer: D. Supraglottic swelling from a thermal burn

    Drooling and painful swallowing point to swelling above the glottis, which can close a child's narrow airway quickly. Anxiety does not cause a muffled voice or drooling.