Airway Management, Ventilation, and Capnography During Cardiac Arrest Practice Questions

25 multiple-choice questions on Airway management, ventilation, and capnography during cardiac arrest for paramedic and EMT students, from Chapter 40 (Responding to the Field Code). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. A 30-year-old man is found hanging and is cut down pulseless and apneic. Compared with a witnessed VF arrest, his resuscitation should especially stress:

   1. A. Compression-only CPR for 6 minutes
   2. B. Spinal immobilization before CPR
   3. C. Holding breaths until he is intubated
   4. D. Early oxygenation and ventilation
   Show answer

   Answer: D. Early oxygenation and ventilation

   Hanging causes an asphyxial arrest, in which the heart stops because of hypoxia, so effective ventilation with oxygen is a key part of CPR from the start, along with compressions. Compression-only CPR is acceptable for bystanders in a sudden cardiac arrest but omits what this patient needs most. Cervical fractures are uncommon in suicidal hangings that do not involve a long drop, and immobilization must never delay CPR; manual stabilization can be used if injury is suspected. Waiting for intubation before ventilating wastes minutes of oxygenation that a bag-mask can provide now. (AHA 2020 and 2025 adult BLS; ERC 2021 special circumstances.)

2. Feedback confirms excellent compressions, yet an intubated patient's ETCO2 stays at 7 mmHg with a good waveform. The most useful step is to:

   1. A. Stop CPR, since ROSC is now impossible
   2. B. Look for a low-flow cause, such as PE
   3. C. Raise the ventilation rate to 20/min
   4. D. Pull the tube back 2 cm and recheck
   Show answer

   Answer: B. Look for a low-flow cause, such as PE

   When compressions are known to be good, a persistently low ETCO2 with a normal waveform suggests very low pulmonary blood flow, so look for causes such as massive pulmonary embolism, severe hypovolemia, or tamponade, and recognize that the outlook is poor. A low ETCO2 alone is not a reason to stop; AHA allows it only as one part of a multimodal decision after 20 minutes of ALS. Faster ventilation lowers ETCO2 further and reduces venous return. A good waveform means the tube is in the trachea, so pulling it back is not indicated. (2025 AHA Part 9.)

3. Bag-mask ventilation is difficult in an obese man in cardiac arrest despite a two-person seal and an OPA. The positioning change most likely to help is:

   1. A. Lay him flat and turn his head well to one side
   2. B. Ramp him so the ear is level with the sternum
   3. C. Tilt him head-down into Trendelenburg
   4. D. Place a pillow under his shoulders alone
   Show answer

   Answer: B. Ramp him so the ear is level with the sternum

   In obesity, ramping the head and upper chest with towels or blankets until the external ear canal is level with the sternal notch aligns the airway, lifts the weight of the chest and abdomen off the diaphragm, and makes mask ventilation and intubation easier, while compressions continue on a firm surface. Turning the head to the side kinks the airway and is avoided if spinal injury is possible. Trendelenburg pushes the abdomen against the diaphragm and worsens ventilation. A shoulder roll alone extends the neck too far in an adult and does not raise the chest and head together. (AHA 2025 adult ALS airway management; NAEMSP airway statement.)

4. Six minutes into a VF arrest, two-rescuer bag-mask ventilation is producing good chest rise and a capnography waveform. The best airway plan is to:

   1. A. Stop CPR now to intubate before more drugs
   2. B. Place an SGA now, pausing CPR to insert it
   3. C. Keep the BVM and place an airway when it fits
   4. D. Bag at 20 per minute until the next rhythm check
   Show answer

   Answer: C. Keep the BVM and place an airway when it fits

   When bag-mask ventilation is working, there is no urgency to place an advanced airway; AHA accepts BVM, a supraglottic airway, or intubation, and the priority in VF is continuous compressions and early defibrillation. An airway can be placed when it will not interrupt CPR. Stopping CPR to intubate creates a harmful pause, and drugs do not require an advanced airway. Pausing compressions to insert a supraglottic airway brings back the very interruption the working BVM avoids. Bagging at 20 per minute is hyperventilation, which raises intrathoracic pressure and reduces venous return. (2025 AHA Part 9; PART and AIRWAYS-2 trials.)

5. After an i-gel is placed during CPR, your partner is squeezing the bag about 25 times per minute. You should:

   1. A. Praise him, since faster breaths add oxygen
   2. B. Have him pause compressions for each breath
   3. C. Switch to a larger adult bag-mask unit
   4. D. Coach him to slow to 1 breath every 6 s
   Show answer

   Answer: D. Coach him to slow to 1 breath every 6 s

   Hyperventilation is common in real resuscitations and reduces blood flow, so the rate should be corrected to 10 per minute; a metronome or the capnograph rate display helps. Pausing compressions for breaths is unnecessary once an advanced airway is in.

6. Current AHA guidance on advanced airways in adult out-of-hospital cardiac arrest states that:

   1. A. SGA or ETT is reasonable, based on crew skill
   2. B. ETT placement is required before epinephrine
   3. C. An SGA should not be used if an ETT is available
   4. D. BVM ventilation is not acceptable once ALS arrives
   Show answer

   Answer: A. SGA or ETT is reasonable, based on crew skill

   AHA allows BVM, supraglottic airway, or intubation in out-of-hospital arrest; intubation is reasonable where providers have high success rates, and an SGA is reasonable where intubation success or training is limited. No airway is required before drugs are given.

7. In the large PART trial of adult out-of-hospital cardiac arrest, initial laryngeal tube placement compared with intubation was associated with:

   1. A. Lower rates of ROSC
   2. B. No difference in outcomes
   3. C. Higher 72-hour survival
   4. D. More aspiration deaths
   Show answer

   Answer: C. Higher 72-hour survival

   PART found higher 72-hour survival and better survival to discharge with an initial laryngeal tube, likely because SGAs are placed faster with fewer interruptions. The AIRWAYS-2 trial found an i-gel noninferior to intubation, which supports choosing the airway that fits the crew's skill.

8. A paramedic and an EMT arrive to find a 60-year-old man in VF. The highest priorities are:

   1. A. Endotracheal intubation and ventilation
   2. B. Compressions and early defibrillation
   3. C. IV access and amiodarone 300 mg
   4. D. Supraglottic airway and capnography
   Show answer

   Answer: B. Compressions and early defibrillation

   Compressions and defibrillation are the only interventions with strong survival evidence in VF, so a small crew must focus on them first. Advanced airways and drugs can follow without interrupting CPR or delaying shocks.

9. After you confirm endotracheal tube placement in an adult in cardiac arrest, which record most helps the team detect later tube movement?

   1. A. The size of laryngoscope blade used
   2. B. The time the cuff was first inflated
   3. C. The color of the patient's lips
   4. D. Tube depth at the teeth or lips
   Show answer

   Answer: D. Tube depth at the teeth or lips

   Recording the centimeter mark at the teeth or lips gives a reference that can be checked after every move; a change in depth warns of migration into a mainstem bronchus or out of the trachea, alongside continuous capnography. The blade size and the time the cuff was inflated do not change as the tube moves and cannot detect migration. Lip color is a late, unreliable sign during CPR, when perfusion is poor anyway. (2025 AHA Part 9; ch40 airway section.)

10. After intubating an adult in cardiac arrest during good CPR, the capnography waveform is flat at 0 mmHg. The most likely cause is:

    1. A. Esophageal tube placement
    2. B. Very high-quality compressions
    3. C. Return of spontaneous circulation
    4. D. Hyperventilation by the bagger
    Show answer

    Answer: A. Esophageal tube placement

    Even during CPR, a tracheal tube shows some CO2 waveform; a flat line suggests esophageal placement, dislodgment, or disconnection and requires immediate reassessment. Hyperventilation lowers ETCO2 but does not flatten the waveform to zero.

11. You cannot get a good mask seal on an arrested man with a thick beard. The best approach is to:

    1. A. Give fewer breaths and accept leaks
    2. B. Use two-person BVM or place an SGA
    3. C. Stop compressions to reposition the mask
    4. D. Rely on compressions alone for an hour
    Show answer

    Answer: B. Use two-person BVM or place an SGA

    Beards commonly prevent a mask seal. A two-person technique with a jaw thrust often improves the seal, and a supraglottic airway can be placed early without stopping compressions. Accepting large leaks gives inadequate ventilation, and pausing compressions should be avoided.

12. Thirty seconds after sodium bicarbonate is pushed during CPR, the ETCO2 jumps from 14 to 30 mmHg and then drifts back down within a minute. This most likely reflects:

    1. A. Return of spontaneous circulation
    2. B. Dislodgment of the ET tube
    3. C. A sudden drop in cardiac output
    4. D. CO2 released by the bicarbonate
    Show answer

    Answer: D. CO2 released by the bicarbonate

    Bicarbonate buffers acid by forming carbon dioxide, which is exhaled and causes a brief rise in ETCO2 that fades as it is cleared. ROSC causes a sustained rise, usually to near-normal levels, and does not fade back to the prior value within a minute; still, check for a pulse at the next rhythm check if the rise persists. A dislodged tube makes the waveform disappear rather than rise. A drop in cardiac output lowers ETCO2. (2025 AHA Part 9 supportive text on ETCO2; ch40 capnography section.)

13. With the same person compressing, the ETCO2 falls from 22 to 9 mmHg over 2 minutes. The most likely cause is:

    1. A. Compressor fatigue
    2. B. Return of circulation
    3. C. Rising cardiac output
    4. D. Improved ventilation
    Show answer

    Answer: A. Compressor fatigue

    Because ETCO2 reflects CPR-generated blood flow, a steady decline usually means compressions are getting shallower; switch compressors and recheck. ROSC causes a rise in ETCO2, not a fall.

14. An adult in cardiac arrest is being ventilated with a bag-mask, and the capnograph at the mask reads 6 mmHg after 20 minutes. Regarding a termination decision, this value:

    1. A. Is enough on its own to stop
    2. B. Proves that ROSC cannot occur
    3. C. Should not be used as a cutoff
    4. D. Must be raised to 10 before stopping
    Show answer

    Answer: C. Should not be used as a cutoff

    The 2025 AHA guidelines allow a failure to reach an ETCO2 above 10 mmHg after 20 minutes of ALS to be one part of a multimodal termination decision only in intubated patients; in nonintubated patients, a specific ETCO2 cutoff should not be used at any time (Class 3: Harm), because no studies have tested it and readings during bag-mask ventilation may not be as reliable as with an advanced airway. No single value is enough on its own to stop, and no value proves that ROSC cannot occur. There is no rule that ETCO2 must be raised to a set number before resuscitation can end; TOR is based on validated rules and medical direction. (2025 AHA Part 9.)

15. During CPR with an i-gel in place, the abdomen becomes steadily more distended and ventilation is getting harder. A helpful next step is to:

    1. A. Pass a gastric tube through its gastric channel
    2. B. Push on the abdomen to force the trapped air back out
    3. C. Raise the ventilation rate to 20 per minute
    4. D. Deflate its cuff to let the air escape
    Show answer

    Answer: A. Pass a gastric tube through its gastric channel

    Second-generation supraglottic airways such as the i-gel have a gastric channel; passing a gastric tube through it decompresses the stomach, improves ventilation, and lowers the risk of regurgitation, while you also check for excessive rate or volume. Pressing on a distended abdomen can force gastric contents up into the airway. A faster rate adds more air and hyperventilation without fixing the problem. The i-gel has no inflatable cuff; its gel seal is not deflated. (Manufacturer instructions for use; 2025 AHA Part 9 airway management.)

16. During adult CPR, supplemental oxygen should be delivered at:

    1. A. A level titrated to SpO2 94% to 98%
    2. B. Room air until ROSC is achieved
    3. C. The highest concentration available
    4. D. 2 L/min by nasal cannula only
    Show answer

    Answer: C. The highest concentration available

    Blood flow is so low during CPR that maximal inspired oxygen is reasonable, and pulse oximetry is unreliable during an arrest. Titrating to an SpO2 target begins after ROSC, when hyperoxia becomes a concern.

17. During CPR, your first intubation attempt fails, and the patient's SpO2 waveform is lost. The best next step is to:

    1. A. Keep trying until the tube is placed
    2. B. Stop compressions for a better view
    3. C. Retry right away without ventilating first
    4. D. Insert a supraglottic airway or use BVM
    Show answer

    Answer: D. Insert a supraglottic airway or use BVM

    After a failed attempt, the priority is oxygenation and ventilation without long pauses, so move to a supraglottic airway or effective bag-mask ventilation; AHA accepts an SGA where intubation success is low, and airway guidance limits the number of attempts. Repeated attempts prolong interruptions and hypoxia and raise the chance of airway trauma. Stopping compressions for a better view creates a long pause in perfusion. Going straight back in without reoxygenating between attempts lets hypoxia deepen. (2025 AHA Part 9; NAEMSP airway position statement.)

18. Some EMS systems use minimally interrupted cardiac resuscitation (MICR) for witnessed shockable arrests. In that approach, early airway care consists of:

    1. A. Immediate intubation before the first shock
    2. B. Passive oxygen by mask with an OPA
    3. C. Bag-mask breaths at 30:2 from the start
    4. D. No airway care of any kind until ROSC
    Show answer

    Answer: B. Passive oxygen by mask with an OPA

    MICR, used by protocol in some systems, gives an initial period of continuous compressions with passive oxygen insufflation through a nonrebreather mask and an oral airway, delaying positive-pressure ventilation and advanced airways so compressions and shocks are not interrupted; Bobrow 2008 reported better survival in witnessed shockable arrests. Immediate intubation before the first shock is the opposite of the MICR approach. Bag-mask breaths at 30:2 are standard CPR, not MICR. MICR still opens the airway and gives oxygen; it does not withhold all airway care, and ventilation begins after the initial cycles. Follow local protocol. (Bobrow 2008; AHA 2015 and 2020 adult BLS.)

19. Excessive gastric inflation during bag-mask ventilation in cardiac arrest increases the risk of:

    1. A. Alveolar rupture from lung overinflation
    2. B. A fall in intrathoracic pressure
    3. C. Improved diaphragm motion
    4. D. Regurgitation and aspiration
    Show answer

    Answer: D. Regurgitation and aspiration

    Air in the stomach raises intragastric pressure, pushes up the diaphragm, and makes regurgitation and aspiration more likely. It raises rather than lowers intrathoracic pressure, restricts rather than improves diaphragm motion, and reduces lung compliance. Alveolar rupture comes from overinflating the lungs themselves, not from air sent into the stomach.

20. Once a supraglottic airway is placed in an adult in arrest, chest compressions should:

    1. A. Pause for 2 breaths after every 30 compressions
    2. B. Stop after each 15 for 2 breaths
    3. C. Continue without pauses for breaths
    4. D. Slow to about 80 per minute
    Show answer

    Answer: C. Continue without pauses for breaths

    With an advanced airway, compressions are continuous at 100 to 120 per minute and breaths are given asynchronously every 6 seconds. Continuing to pause at 30:2 lowers the compression fraction for no benefit, provided the SGA seals well.

21. After i-gel placement during CPR, you hear a large air leak and see poor chest rise. You should:

    1. A. Accept it, since SGA leaks are expected
    2. B. Reposition or replace it, or use BVM
    3. C. Raise the ventilation rate to 20/min
    4. D. Stop compressions so the leak can seal
    Show answer

    Answer: B. Reposition or replace it, or use BVM

    A large leak with poor chest rise means the SGA is not ventilating, so it must be adjusted, resized, or abandoned for BVM or another airway. A faster rate only adds hyperventilation risk without fixing the leak.

22. During cardiac arrest, the ETCO2 value mainly reflects:

    1. A. Pulmonary blood flow generated by CPR
    2. B. Arterial oxygen saturation in the blood
    3. C. The depth of the patient's coma
    4. D. Tidal volume delivered alone
    Show answer

    Answer: A. Pulmonary blood flow generated by CPR

    With a constant ventilation rate, ETCO2 rises and falls with the blood flow CPR pushes through the lungs, which makes it a real-time gauge of compression quality. It does not measure oxygenation.

23. Besides confirming tube placement, the capnograph's respiratory rate display during CPR helps the team:

    1. A. Measure the depth of compressions
    2. B. Confirm the tidal volume of each breath
    3. C. Catch excessive ventilation rates
    4. D. Count the compression rate per minute
    Show answer

    Answer: C. Catch excessive ventilation rates

    The capnograph counts each exhaled breath, so a displayed rate of 20 or 30 instantly shows the bagger is hyperventilating. Compression depth and compression rate require a CPR feedback device, and the capnograph does not measure the volume of each breath.

24. While you are ventilating an adult in arrest with a bag-mask, he vomits. You should:

    1. A. Suction, then resume ventilating
    2. B. Continue bagging through the vomitus
    3. C. Stop CPR until an ETT is in place
    4. D. Slow the bag rate and keep ventilating
    Show answer

    Answer: A. Suction, then resume ventilating

    Vomitus must be cleared by suction, or by briefly turning the patient, before ventilation continues, or it will be forced into the lungs; compressions continue except for the brief pause needed. Bagging through it causes aspiration, and slowing the bag rate still pushes the vomitus into the lungs. Holding compressions until intubation creates a long, harmful pause. (2025 AHA Part 9 airway management.)

25. During an arrest, ET tube position should be reconfirmed with capnography:

    1. A. Only at the time of placement
    2. B. After every patient move
    3. C. Only if the SpO2 begins to drop
    4. D. Once on arrival at the hospital
    Show answer

    Answer: B. After every patient move

    Tubes are easily dislodged when the patient is moved to a stretcher, carried, or loaded, so placement should be rechecked after every move and monitored continuously. SpO2 is unreliable during CPR and would detect dislodgment late.