NREMT Paramedic Cognitive ExamCardiology & ResuscitationMedium
A 60-year-old male presents with sudden onset of substernal chest pressure, radiating to his left arm and jaw. He is diaphoretic and dyspneic. His vital signs are BP 140/90 mmHg, HR 98 bpm, RR 20 bpm, SpO2 94% on room air. An ECG shows ST elevation in leads II, III, and aVF. Which of the following medications is MOST likely to be contraindicated in this patient due to the ECG findings?
- AMorphine
- BOxygen
- CNitroglycerin
- DAspirin
Show answer & explanationAnswer & explanation
Correct answer: C. Nitroglycerin
The ECG findings of ST elevation in leads II, III, and aVF indicate an inferior wall myocardial infarction. Nitroglycerin is relatively contraindicated in inferior MIs due to the risk of profound hypotension and worsening cardiac output, especially if there is associated right ventricular involvement.
Why the other options are wrong
- A. Morphine is used for pain relief in acute coronary syndrome if nitroglycerin is ineffective or contraindicated.
- B. Oxygen is indicated for hypoxemia (SpO2 < 94%) or respiratory distress in acute coronary syndrome.
- D. Aspirin is indicated for suspected myocardial infarction to inhibit platelet aggregation.
Nitroglycerin Contraindications in Inferior MI
Nitroglycerin is relatively contraindicated in patients with acute inferior myocardial infarction due to potential for profound hypotension, especially if right ventricular involvement is suspected.
- Inferior MI often affects the right ventricle, which is preload dependent.
- Nitroglycerin causes vasodilation, reducing preload.
- Reduced preload in a preload-dependent right ventricle can lead to severe hypotension and cardiogenic shock.
Memory trick: Inferior MI, Think Right Heart, Don't Drop the Pressure!