Critical Airway Decisions and the Physiologically Difficult Airway Practice Questions

25 multiple-choice questions on Critical airway decisions and the physiologically difficult airway for paramedic and EMT students, from Chapter 41 (Management and Resuscitation of the Critical Patient). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. A 'physiologically difficult' airway is one in which:

   1. A. The anatomy makes the vocal cords hard to see on laryngoscopy
   2. B. The patient has a short neck and a small mouth opening
   3. C. Shock, hypoxemia, or acidosis raise the risk of arrest
   4. D. The laryngoscope view is obscured by blood or vomit
   Show answer

   Answer: C. Shock, hypoxemia, or acidosis raise the risk of arrest

   A physiologically difficult airway is one where hypotension, hypoxemia, acidosis, or right heart failure make the patient likely to deteriorate or arrest around intubation, even if the view is easy. Poor visualization from anatomy describes an anatomically difficult airway.

2. The 'HOp killers' of emergency airway management are:

   1. A. Hypothermia, obesity, and pharyngeal edema
   2. B. Hyperkalemia, opioid use, and a simple pneumothorax
   3. C. Head injury, obstruction, and poor dentition
   4. D. Hypotension, hypoxemia, and metabolic acidosis
   Show answer

   Answer: D. Hypotension, hypoxemia, and metabolic acidosis

   Hypotension, oxygenation failure, and low pH are the physiologic derangements most associated with peri-intubation cardiac arrest. Each should be corrected or mitigated before induction whenever time allows.

3. During an intubation attempt on a patient in shock with cold hands, the finger SpO2 still reads 95%, but his lips are turning dusky. You should keep in mind that:

   1. A. Cyanosis cannot occur at a saturation of 95%
   2. B. A finger probe can lag behind the true value
   3. C. A reading of 95% rules out hypoxemia
   4. D. Finger probes read faster in shock than in health
   Show answer

   Answer: B. A finger probe can lag behind the true value

   With vasoconstriction and low output, blood takes longer to reach a finger probe, so the displayed SpO2 can trail the real central saturation by many seconds and miss a rapid fall during apnea; an ear or forehead probe responds faster, and clinical signs such as central cyanosis should be believed. Cyanosis appearing at the lips means the true saturation is already low, whatever the finger shows. One reading cannot rule out hypoxemia when the probe is lagging. Poor perfusion slows, rather than speeds, the probe's response.

4. A shock index of 0.9 or higher before intubation predicts:

   1. A. Post-intubation hypotension and cardiac arrest
   2. B. A difficult laryngoscopic view of the vocal cords
   3. C. Rapid desaturation from a small lung volume
   4. D. Improved hemodynamics after paralysis
   Show answer

   Answer: A. Post-intubation hypotension and cardiac arrest

   A pre-intubation shock index of 0.9 or more is associated with post-intubation hypotension and arrest, signaling a need for fluids, blood, or a pressor first. It does not predict the laryngoscopic view, which depends on anatomy.

5. A 61-year-old septic patient needs intubation for worsening mental status. HR 128, BP 88/50 mmHg, SpO2 90% on a nonrebreather. The best preparation is:

   1. A. Immediate induction with a full dose of midazolam
   2. B. Fluid, a pressor ready, and better preoxygenation
   3. C. Intubation without any medication to avoid hypotension
   4. D. Hyperventilation with a BVM at 30 breaths per minute
   Show answer

   Answer: B. Fluid, a pressor ready, and better preoxygenation

   With a shock index of about 1.5 and marginal saturation, she is at high risk of arrest; giving fluid, having push-dose epinephrine ready, and improving preoxygenation reduce that risk. Full-dose midazolam is a strong vasodilator and myocardial depressant in shock.

6. For induction in a hypotensive patient, which strategy is most appropriate?

   1. A. Propofol at the full standard dose
   2. B. Midazolam at twice the usual dose
   3. C. Fentanyl at a high dose pushed rapidly IV
   4. D. Ketamine or etomidate at a reduced dose
   Show answer

   Answer: D. Ketamine or etomidate at a reduced dose

   Ketamine and etomidate are the most hemodynamically stable induction agents, and in shock their doses are reduced because the patient needs less drug and circulation is slow. Propofol causes vasodilation and myocardial depression that can precipitate arrest.

7. Why is a higher dose of rocuronium often recommended for rapid sequence intubation in shock?

   1. A. The drug is cleared by the kidneys much faster in shock
   2. B. Acidosis makes the receptors resist the drug
   3. C. Low cardiac output slows its arrival at the muscles
   4. D. Catecholamines in shock compete at the receptor
   Show answer

   Answer: C. Low cardiac output slows its arrival at the muscles

   Poor circulation delays the drug's onset, and a larger dose, about 1.2 to 1.6 mg/kg, provides faster, more reliable paralysis. Clearance falls rather than rises in shock, acidosis tends to potentiate rather than resist nondepolarizing blockade, and catecholamines do not compete with rocuronium at the receptor. Rocuronium has no meaningful effect on blood pressure.

8. You are preparing to intubate a 54-year-old with pneumonia whose SpO2 is 89% on a nonrebreather. Before induction, the saturation you should aim for, if achievable, is at least:

   1. A. 80% to 85%
   2. B. 85% to 88%
   3. C. 88% to 90%
   4. D. 93% to 95%
   Show answer

   Answer: D. 93% to 95%

   Starting near 95% provides a buffer, because once saturation drops below about 90% it falls rapidly down the steep part of the oxyhemoglobin curve. Starting at 88% leaves almost no safe apnea time.

9. You are preoxygenating a patient who is breathing 32 times a minute with a nonrebreather mask. The best way to bring his inspired oxygen closer to 100% is to:

   1. A. Turn the oxygen up to flush rate
   2. B. Lower the flow so the reservoir collapses
   3. C. Remove the reservoir bag from the mask
   4. D. Switch to a simple face mask at 10 L/min
   Show answer

   Answer: A. Turn the oxygen up to flush rate

   A rapidly breathing patient pulls in more air than 15 L/min can supply, so room air leaks in around the mask and dilutes the oxygen; running the flowmeter at flush rate (often 40 L/min or more) keeps up with demand and raises the inspired fraction, which is why many airway guides recommend it for preoxygenation. A collapsing reservoir means the patient is outbreathing the supply. Removing the reservoir lowers the oxygen delivered. A simple face mask delivers less oxygen than a nonrebreather.

10. A patient in prolonged septic shock on high-dose norepinephrine becomes more hypotensive right after a ketamine induction dose. The most likely reason is that:

    1. A. It is a strong direct vasodilator
    2. B. Its direct heart depression is unmasked
    3. C. It blocks norepinephrine receptors
    4. D. It releases histamine, causing anaphylaxis
    Show answer

    Answer: B. Its direct heart depression is unmasked

    Ketamine usually supports blood pressure by releasing catecholamines, but it also directly depresses the myocardium. In a patient whose catecholamine stores are exhausted by prolonged shock, the indirect support is lost and the direct depression shows, so even ketamine is given at a reduced dose with a pressor ready. Ketamine is not a strong vasodilator. It does not block adrenergic receptors. It does not cause meaningful histamine release or anaphylaxis.

11. A patient with ARDS-like pneumonia does not reach an SpO2 above 88% with a nonrebreather mask. To improve preoxygenation, you should next consider:

    1. A. A nasal cannula at 4 L/min alone
    2. B. A simple face mask at 6 L/min
    3. C. A BVM with a PEEP valve or CPAP
    4. D. Waiting 10 more minutes on the NRB
    Show answer

    Answer: C. A BVM with a PEEP valve or CPAP

    Shunt physiology from fluid-filled alveoli responds to positive end-expiratory pressure, which recruits alveoli, so a BVM with PEEP or noninvasive ventilation is more effective than more mask oxygen. Simple masks deliver less oxygen than the NRB.

12. A 60-year-old with cancer has JVD, muffled heart sounds, a BP of 84/66 mmHg, and worsening mental status. Before any intubation attempt, the main hazard to plan for is that positive pressure will:

    1. A. Raise his blood pressure too far after induction
    2. B. Cause a tension pneumothorax in most patients
    3. C. Increase venous return and overload the ventricles
    4. D. Further limit filling of the compressed heart
    Show answer

    Answer: D. Further limit filling of the compressed heart

    In cardiac tamponade the heart can fill only while venous pressure exceeds the pericardial pressure. Positive-pressure breaths raise chest pressure and cut venous return further, which can cause arrest right after induction. Keep him breathing on his own if possible, give fluid, and get pericardial drainage. Positive pressure lowers venous return; it does not increase it.

13. Shortly after intubation, a patient's blood pressure falls from 98/60 to 62/40 mmHg. Which cause should you consider first?

    1. A. Less venous return from positive pressure
    2. B. Rocuronium's direct vasodilating effect
    3. C. Hypoglycemia from the stress of induction
    4. D. Increased sympathetic tone from the laryngoscopy
    Show answer

    Answer: A. Less venous return from positive pressure

    Positive pressure raises intrathoracic pressure and reduces venous return, while induction drugs remove the sympathetic drive that was supporting the pressure. Laryngoscopy usually causes a transient rise in pressure, not a fall. Rocuronium has no meaningful effect on blood pressure, and induction does not cause hypoglycemia that would drop the pressure this fast.

14. A bleeding trauma patient becomes more hypotensive after intubation. He is being bagged at 24 breaths/min with a PEEP valve set at 10 cmH2O. A helpful change is to:

    1. A. Raise the PEEP valve to 15 cmH2O
    2. B. Bag faster to clear more CO2
    3. C. Slow the rate and lower the PEEP
    4. D. Use larger breaths of 10 mL/kg
    Show answer

    Answer: C. Slow the rate and lower the PEEP

    Positive pressure raises intrathoracic pressure and reduces venous return, and the effect is largest in a hypovolemic patient; fast rates, large breaths, and high PEEP all add to it. Slowing the rate (about 10 per minute), using modest tidal volumes, and keeping PEEP low while blood is given improves venous return. Raising PEEP or bagging faster increases intrathoracic pressure further. Larger tidal volumes do the same and risk lung injury.

15. A patient with a pH of 7.05 and RR 36 before intubation is placed on a ventilator at 12 breaths/min. The most likely result is:

    1. A. Improved oxygenation and a rising blood pressure
    2. B. Worsening acidosis that can cause cardiac arrest
    3. C. Better clearance of lactate through the lungs
    4. D. A gradual normalization of the pH over hours
    Show answer

    Answer: B. Worsening acidosis that can cause cardiac arrest

    The patient was compensating with a very high minute ventilation; a lower rate allows CO2 to build up and the pH to fall further, risking arrest. Ventilation should initially match the pre-intubation minute ventilation.

16. Before RSI for a 45-year-old found with a GCS of 8 and snoring respirations, which quick check could avoid the need for intubation altogether?

    1. A. A 12-lead ECG
    2. B. A core body temperature
    3. C. A peak flow reading
    4. D. A blood glucose level
    Show answer

    Answer: D. A blood glucose level

    Hypoglycemia is a common, quickly reversible cause of a depressed level of consciousness, and treating it with dextrose can restore mentation and protective reflexes within minutes, making intubation unnecessary; other reversible causes, such as opioid toxicity, should be considered in the same way. A 12-lead ECG does not reveal a cause that reverses coma on the spot. A core temperature matters but does not usually make intubation unnecessary. A peak flow needs a cooperative patient and has no role in a comatose one.

17. Induction drug doses are reduced in patients in shock mainly because:

    1. A. Shock speeds up drug clearance by the kidneys
    2. B. Shock makes the brain less sensitive to drugs
    3. C. A larger share of each dose reaches the brain
    4. D. Low albumin leaves less drug free in plasma
    Show answer

    Answer: C. A larger share of each dose reaches the brain

    In shock, blood flow is redirected to the brain and heart, and the circulating volume that dilutes a drug is smaller, so a standard dose produces a higher brain concentration and a greater fall in blood pressure; reduced doses of ketamine or etomidate give adequate effect with less hemodynamic harm. Kidney clearance falls, rather than rises, in shock. The brain becomes more, not less, sensitive to the drug, and low albumin raises rather than lowers the free fraction of protein-bound drugs.

18. A 46-year-old woman with a massive pulmonary embolism is hypotensive and hypoxic. Why is intubation especially dangerous in her?

    1. A. Positive pressure can push the failing right ventricle into arrest
    2. B. Her airway is likely to be swollen and anatomically difficult to see
    3. C. Pulmonary emboli cause severe laryngospasm during intubation
    4. D. Induction drugs dissolve the clot and cause a rapid bleed
    Show answer

    Answer: A. Positive pressure can push the failing right ventricle into arrest

    Raised intrathoracic pressure increases right ventricular afterload and lowers preload, which can cause collapse of a right ventricle already strained by the clot. If intubation is needed, it is done with pressors ready and minimal ventilation pressures.

19. During bag-mask preoxygenation of a hypotensive patient, a capnography adapter is placed between the mask and the bag. A good square waveform mainly confirms that:

    1. A. The patient's blood pressure is adequate
    2. B. Air is moving in and out of the lungs
    3. C. The oxygen saturation is above 94%
    4. D. The tube will be easy to place
    Show answer

    Answer: B. Air is moving in and out of the lungs

    A square ETCO2 waveform during bag-mask ventilation shows that CO2 is coming out of the lungs, so the mask seal and airway are open and gas exchange is happening; a flat line suggests a leak or obstruction. The waveform can reflect perfusion over time, but it does not show that the blood pressure is adequate. It says nothing about oxygen saturation, which needs a pulse oximeter. It does not predict how difficult laryngoscopy will be.

20. Your partner suggests intubating a hypotensive patient with sedation alone and no paralytic, 'to protect the pressure.' The main problem with this approach is:

    1. A. Rocuronium is needed to prevent awareness
    2. B. Ketamine given alone stops spontaneous breathing
    3. C. Lower first-pass success and more complications
    4. D. Sedation alone is barred in cardiac arrest
    Show answer

    Answer: C. Lower first-pass success and more complications

    NAEMSP recommends that drug-assisted intubation use both an induction agent and a neuromuscular blocker, because sedation alone gives poorer views, more attempts, more vomiting and aspiration, and lower first-pass success; the hypotension is handled by resuscitating first and reducing the induction dose, not by withholding the paralytic. A paralytic provides no sedation or protection from awareness, and ketamine given alone usually preserves spontaneous breathing rather than stopping it. Cardiac arrest does not need drugs for intubation at all, so that is not the issue here.

21. After intubation with rocuronium, a septic patient's BP is 86/50 mmHg. The best approach to post-intubation sedation is:

    1. A. Titrated small doses, pressor at hand
    2. B. Withhold sedation until the BP is normal
    3. C. A large fentanyl bolus pushed rapidly IV
    4. D. A second dose of rocuronium instead
    Show answer

    Answer: A. Titrated small doses, pressor at hand

    Rocuronium lasts far longer than the induction agent, so the patient will be paralyzed and possibly aware unless sedation and analgesia are started; in a hypotensive patient they are given in small, repeated doses (for example, fentanyl or ketamine) while the pressure is supported with fluid or a vasopressor. Withholding sedation risks awareness under paralysis. A large rapid bolus can drop the pressure sharply. More paralytic adds no sedation and hides signs of awareness.

22. During your first intubation attempt, the patient's SpO2 falls from 96% to 91%. You should:

    1. A. Keep trying, since the tube is almost in position
    2. B. Switch to a larger blade and keep the scope in place
    3. C. Wait until the saturation reaches 70% before stopping
    4. D. Stop and reoxygenate with a BVM, then retry
    Show answer

    Answer: D. Stop and reoxygenate with a BVM, then retry

    Saturation falls rapidly once it drops below about 90%, so the attempt should be aborted and the patient reoxygenated. Pressing on with a falling saturation risks hypoxic bradycardia and arrest.

23. A 70-year-old with GI bleeding is vomiting blood and is hypotensive with a GCS of 9. Which approach best reduces the risk of peri-intubation arrest?

    1. A. Rapid intubation before any resuscitation is attempted
    2. B. Blood first, suction ready, and a pressor drawn up
    3. C. Prolonged BVM ventilation at a high rate before induction
    4. D. Full-dose propofol to provide smooth induction conditions
    Show answer

    Answer: B. Blood first, suction ready, and a pressor drawn up

    He has both anatomic (blood) and physiologic (hypotension) difficulty, so resuscitation, large-bore suction, and a pressor ready address both. Aggressive BVM ventilation inflates the stomach and increases the risk of aspiration.

24. The main reason first-pass success matters in critical patients is that:

    1. A. A second attempt is not allowed by most EMS protocols
    2. B. Each added attempt raises the risk of hypoxia and arrest
    3. C. The first attempt gives the best laryngoscopic view
    4. D. A failed attempt makes the airway easier on the next try
    Show answer

    Answer: B. Each added attempt raises the risk of hypoxia and arrest

    Multiple attempts are associated with desaturation, aspiration, airway trauma, and cardiac arrest, so preparation focuses on getting it right the first time. Protocols generally allow more than one attempt, so the risk to the patient, not a rule, is the reason. The first view is not reliably the best, since repositioning or a bougie can improve later views. Edema and bleeding from failed attempts make later attempts harder, not easier.

25. Which patient is the best candidate to avoid intubation and use a supraglottic airway as the initial advanced airway?

    1. A. An alert patient having an asthma attack with loud wheezing
    2. B. A patient with facial burns and stridor
    3. C. An unresponsive patient in cardiac arrest during CPR
    4. D. A patient with a foreign body in the larynx
    Show answer

    Answer: C. An unresponsive patient in cardiac arrest during CPR

    A supraglottic airway is quick to place, does not interrupt compressions, and performs well in cardiac arrest. It is contraindicated in a responsive patient and offers little protection when the obstruction or swelling is at the glottis.