CCI Cardiac Pharmacology and Hemodynamic Monitoring 2 — Questions and Answers
Question 1: Which invasive hemodynamic measurement is obtained by the thermodilution technique using a pulmonary artery (Swan-Ganz) catheter?
- Systemic arterial pressure
- Cardiac output (Correct answer)
- Left ventricular end-diastolic pressure
- Coronary artery pressure gradient
Correct answer: Cardiac output
Thermodilution cardiac output is measured by injecting cold saline into the right atrium and detecting the temperature change downstream in the pulmonary artery to calculate flow.
Question 2: In the Fick method for cardiac output calculation, what three variables are required?
- Heart rate, stroke volume, and PCWP
- Oxygen consumption, arterial O₂ content, and mixed venous O₂ content (Correct answer)
- Systolic BP, diastolic BP, and heart rate
- CVP, PCWP, and mean PAP
Correct answer: Oxygen consumption, arterial O₂ content, and mixed venous O₂ content
The Fick principle states CO = VO₂ / (CaO₂ – CvO₂), requiring whole-body oxygen consumption, arterial oxygen content, and mixed venous oxygen content.
Question 3: Which pharmacologic agent is a phosphodiesterase-3 inhibitor used for short-term IV support in decompensated heart failure?
- Digoxin
- Milrinone (Correct answer)
- Dopamine
- Vasopressin
Correct answer: Milrinone
Milrinone inhibits phosphodiesterase-3, increasing cAMP, leading to positive inotropy and vasodilation (inodilator), used for short-term support in acute decompensated heart failure.
Question 4: What is the primary indication for using adenosine during cardiac catheterization for fractional flow reserve (FFR) measurement?
- To increase heart rate and detect wall motion abnormalities
- To induce maximal coronary hyperemia for accurate pressure gradient measurement (Correct answer)
- To reverse the effect of heparin anticoagulation
- To treat contrast-induced allergic reactions
Correct answer: To induce maximal coronary hyperemia for accurate pressure gradient measurement
Adenosine induces maximal coronary hyperemia by maximally dilating the coronary microvasculature, which is required to accurately calculate FFR from the pressure gradient across a stenosis.
Question 5: Which hemodynamic profile best describes cardiogenic shock?
- Low PCWP, low SVR, high cardiac output
- High PCWP, high SVR, low cardiac output (Correct answer)
- Normal PCWP, low SVR, low cardiac output
- Low PCWP, high SVR, normal cardiac output
Correct answer: High PCWP, high SVR, low cardiac output
Cardiogenic shock presents with elevated PCWP (congestion), compensatory high SVR (vasoconstriction), and low cardiac output reflecting pump failure.
Question 6: What is the therapeutic target INR range for patients with mechanical heart valves requiring warfarin anticoagulation (mitral position)?
- 1.5–2.0
- 2.0–3.0
- 2.5–3.5 (Correct answer)
- 3.5–4.5
Correct answer: 2.5–3.5
For mechanical mitral valve prostheses, the AHA/ACC recommended INR target is 2.5–3.5 due to higher thromboembolic risk compared to aortic position valves.
CCI Cardiac Pharmacology and Hemodynamic Monitoring 2
Which invasive hemodynamic measurement is obtained by the thermodilution technique using a pulmonary artery (Swan-Ganz) catheter?