A 65-year-old male presents to the emergency department with complaints of severe shortness of breath and chest pain. He has a history of myocardial infarction and congestive heart failure. On physical exam, he is diaphoretic, hypotensive with a blood pressure of 80/50 mmHg, heart rate of 120 bpm, and jugular venous distension. His lungs reveal crackles bilaterally. An ECG shows ST-segment elevation in the anterior leads, and troponin levels are significantly elevated. Bedside echocardiography reveals an ejection fraction of 25% with global hypokinesis.
Which of the following is the most appropriate immediate treatment?
A) Intravenous fluids bolus
B) Nitroglycerin infusion
C) Norepinephrine infusion
D) Non-invasive positive pressure ventilation
Answer: C) Norepinephrine infusion
Explanation:
This patient is in cardiogenic shock, likely secondary to acute myocardial infarction (AMI) based on his history, clinical presentation, and ECG findings.
Norepinephrine is widely recommended as a front-line agent for cardiogenic shock. Norepinephrine will improve the blood pressure, but there is a risk that excessive afterload could drop the cardiac output. The cath team should be notified ASAP if MI is the suspected cause of cardiogenic shock. Early consultation of the heart failure team can help guide further management if available at your institution.
Key Points:
- Cardiogenic shock occurs when there is inadequate tissue perfusion due to the failure of the heart as a pump. It is typically characterized by hypotension, signs of poor perfusion (cold extremities, altered mental status), and pulmonary congestion.
- The most common cause is an acute myocardial infarction (AMI), leading to severe left ventricular dysfunction. Other causes include Takotsubo, Peripartum Cardiomyopathy, Myocarditis, and Tachymyopathy
Choices:
- A) Intravenous fluids bolus: Fluid boluses are generally avoided in cardiogenic shock because the failing heart cannot effectively pump the excess fluid, which can worsen pulmonary edema. This patient already shows signs of volume overload (crackles in the lungs and jugular venous distension).
- B) Nitroglycerin infusion: Although nitroglycerin can reduce preload and improve ischemia in stable patients with myocardial infarction, it is contraindicated in this case due to the patient’s hypotension. Reducing preload or blood pressure further would worsen the shock.
- C) Norepinephrine infusion: This is the correct answer. In cardiogenic shock, vasopressors such as norepinephrine are used to maintain perfusion by increasing systemic vascular resistance and cardiac output. Norepinephrine is often preferred because it has strong vasoconstrictive effects and some inotropic support, making it suitable for patients in cardiogenic shock with hypotension.
- D) Non-invasive positive pressure ventilation (NIPPV): While NIPPV can help manage pulmonary edema and improve oxygenation, it does not address the underlying hypotension or poor cardiac output, which are the primary concerns in this case. This may be useful in conjunction with vasopressors but is not the initial definitive treatment for shock.
Takeaway: In patients with cardiogenic shock, the first-line treatment often includes vasopressors, such as norepinephrine, to stabilize blood pressure and ensure adequate organ perfusion while addressing the underlying cause (e.g., revascularization in myocardial infarction).
References:
- Tintinalli’s Emergency Medicine Manual, 9th Edition
- Internet Book of Critical Care
