📊 Capnography Quiz

Paramedic-level waveform interpretation and clinical decision-making based on real NREMT topics

🎯 NREMT Focus Areas

This quiz covers high-yield capnography topics frequently tested on the Paramedic NREMT:

Shark fin waveform - Bronchospasm recognition and treatment escalation
Medication interactions - Beta-blockers (metoprolol) and bronchodilators
ROSC detection - Using ETCO2 during cardiac arrest
Treatment algorithms - When home medications fail

💡 NREMT Tip: The exam loves scenarios where a patient's home medications aren't working. When you see asthma + failed home nebs + shark fin capnography = escalate to CPAP, epinephrine, and methylprednisolone.

Question 1 of 10

A 28-year-old female with known asthma is having a severe attack. She received 3 home nebulizer treatments without improvement. She can only speak single words, has diminished breath sounds bilaterally, and SpO2 is 85%. Her capnography shows this waveform:

In addition to CPAP and bronchodilators, what medication should be considered for this patient?

A. Adenosine
B. Epinephrine IM or SQ
C. Diphenhydramine
D. Naloxone

✅ Explanation

In severe, refractory asthma (status asthmaticus) where standard bronchodilators fail, epinephrine (IM 0.3-0.5mg or SQ) provides additional bronchodilation through alpha and beta effects. The shark fin waveform confirms severe bronchospasm. CPAP, albuterol, ipratropium, and methylprednisolone are also indicated. This combination of failed home treatment + severe presentation + shark fin capnography = escalate to epinephrine.

Question 2 of 10

During CPR on a cardiac arrest patient, you notice the ETCO2 suddenly increases from 14 mmHg to 42 mmHg and the waveform changes as shown:

What is the MOST likely cause of this change?

A. The endotracheal tube has become displaced
B. Return of spontaneous circulation (ROSC)
C. Tension pneumothorax developing
D. Hyperventilation by the BVM operator

✅ Explanation

A sudden, significant rise in ETCO2 during CPR (typically to 35-40+ mmHg) is one of the earliest indicators of ROSC - often appearing before a palpable pulse. This occurs because restored circulation delivers more CO2 to the lungs. Stop CPR and check for pulse/rhythm. This is a HIGH-YIELD NREMT topic.

Question 3 of 10

You are ventilating an intubated patient and notice the ETCO2 has dropped to 22 mmHg with this waveform pattern:

What is the MOST appropriate intervention?

A. Increase the ventilation rate
B. Decrease the ventilation rate
C. Check for tube displacement
D. Suction the airway

✅ Explanation

Low ETCO2 with a normal-shaped but frequent waveform indicates hyperventilation - you are blowing off too much CO2. This is harmful in head injury patients (causes cerebral vasoconstriction) and can cause respiratory alkalosis. Slow the ventilation rate to 10-12/min for adults. Target ETCO2 of 35-45 mmHg in most patients.

Question 4 of 10

A 55-year-old male with altered mental status has slow, shallow respirations. ETCO2 is 58 mmHg. You observe this waveform:

This waveform pattern with elevated ETCO2 indicates:

A. Hyperventilation - decrease oxygen flow
B. Hypoventilation - assist ventilations
C. Normal ventilation - continue monitoring
D. Equipment malfunction

✅ Explanation

Elevated ETCO2 (>45 mmHg) with slow, wide waveforms indicates hypoventilation - the patient is not breathing adequately to eliminate CO2. This requires assisted ventilations with BVM. Common causes include opioid overdose, sedation, head injury, or respiratory muscle fatigue. Consider naloxone if opioid overdose is suspected.

Question 5 of 10

You have intubated a cardiac arrest patient. After 2 minutes of CPR, you check the capnography and see this waveform with ETCO2 of 12 mmHg:

What does this capnography reading indicate?

A. Tube is in the esophagus - reintubate immediately
B. Normal reading - continue current resuscitation efforts
C. ROSC has occurred - check for pulse
D. Hyperventilation - slow the ventilation rate

✅ Explanation

During CPR, ETCO2 of 10-20 mmHg with a normal square waveform indicates proper tube placement and adequate chest compressions. The waveform confirms CO2 is being exhaled (tube is in trachea). ETCO2 < 10 suggests poor perfusion/compressions. ETCO2 suddenly rising to 35-40+ during CPR suggests ROSC.

Question 6 of 10

A 62-year-old male with COPD is in severe respiratory distress. He takes metoprolol at home for hypertension. His home nebulizer and oxygen are not improving his condition. Capnography shows this waveform with ETCO2 of 65 mmHg:

This patient is on metoprolol. Which bronchodilator consideration is MOST important?

A. Metoprolol will enhance the effects of albuterol
B. Beta-blockers like metoprolol may reduce bronchodilator effectiveness
C. Metoprolol is contraindicated with any nebulizer treatment
D. Metoprolol has no interaction with respiratory medications

✅ Explanation

Beta-blockers (metoprolol, atenolol, propranolol) can reduce the effectiveness of beta-agonist bronchodilators like albuterol because they compete for the same receptors. This is a key NREMT concept - patients on beta-blockers may require higher doses or additional interventions (CPAP, epinephrine for severe cases, steroids) when standard bronchodilators are less effective. The shark fin waveform confirms ongoing bronchospasm.

Question 7 of 10

You respond to a 45-year-old female with severe shortness of breath. She has a history of asthma and states her home nebulizer treatments are not helping. She is sitting in tripod position, speaking in 2-word sentences. SpO2 is 88% on room air. You attach capnography and observe this waveform:

Based on this waveform and presentation, what is the MOST appropriate treatment?

A. Albuterol nebulizer only
B. CPAP with albuterol and consider methylprednisolone
C. Bag-valve mask ventilation
D. High-flow oxygen via non-rebreather only

✅ Explanation

The "shark fin" waveform indicates bronchospasm with obstructed exhalation - classic for severe asthma/COPD exacerbation. When home medications fail and the patient is in respiratory distress, escalate treatment: CPAP helps splint airways open, nebulized albuterol addresses bronchospasm, and methylprednisolone (Solu-Medrol) reduces inflammation. This is a common NREMT scenario testing your ability to recognize when standard treatments are insufficient.

Question 8 of 10

You are transporting an intubated patient on a ventilator. You notice a "notch" or dip in the plateau phase of the capnography waveform:

This "curare cleft" pattern indicates:

A. The patient needs more sedation - they are trying to breathe
B. The ventilator is malfunctioning
C. Esophageal intubation
D. Bronchospasm is developing

✅ Explanation

The "curare cleft" (dip in the plateau) occurs when the patient attempts to breathe against the ventilator - indicating inadequate sedation or paralysis wearing off. The patient's inspiratory effort causes the dip. Consider additional sedation to improve ventilator synchrony and patient comfort. Named after curare, an early paralytic agent.

Question 9 of 10

You notice the capnography baseline is not returning to zero between breaths as shown:

What does an elevated baseline on capnography typically indicate?

A. Proper tube placement confirmed
B. Rebreathing of exhaled CO2
C. Cardiac arrest is imminent
D. The patient is hyperventilating

✅ Explanation

When the capnography baseline does not return to zero, the patient is rebreathing their own exhaled CO2. Common causes include inadequate fresh gas flow, exhausted CO2 absorber, or a faulty expiratory valve. Check equipment, increase oxygen flow, and ensure proper ventilator/BVM function.

Question 10 of 10

You intubate a patient and attach capnography. After 6 ventilations, you observe this waveform:

What does this waveform pattern indicate?

A. Proper endotracheal tube placement
B. Esophageal intubation - remove tube and reoxygenate
C. Bronchospasm requiring treatment
D. Right mainstem intubation

✅ Explanation

A rapidly diminishing or absent waveform after intubation indicates esophageal placement. Gastric CO2 may produce small initial waveforms that quickly disappear. Proper tracheal placement shows consistent square waveforms that persist. Remove the tube immediately, reoxygenate with BVM, and reattempt intubation. Never leave a misplaced tube.

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📊 Capnography Quiz

🎯 NREMT Focus Areas

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