CSC Hemodynamic Monitoring & Assessment 2 — Questions and Answers
Question 1: Cardiac index is calculated by dividing cardiac output by:
- Heart rate
- Body surface area (Correct answer)
- Stroke volume
- Mean arterial pressure
Correct answer: Body surface area
Cardiac index normalizes cardiac output to body surface area (L/min/m²), allowing comparison across patients of different sizes.
Question 2: Which condition is most likely when pulmonary artery diastolic pressure significantly exceeds PCWP?
- Left ventricular failure
- Pulmonary hypertension (Correct answer)
- Mitral stenosis
- Aortic regurgitation
Correct answer: Pulmonary hypertension
Elevated pulmonary artery diastolic–PCWP gradient (>5 mmHg) indicates increased pulmonary vascular resistance, as seen in pulmonary hypertension.
Question 3: Mixed venous oxygen saturation (SvO₂) measured via pulmonary artery catheter normally ranges from:
- 30–40%
- 50–55%
- 60–75% (Correct answer)
- 85–95%
Correct answer: 60–75%
Normal SvO₂ is 60–75%, reflecting the oxygen remaining in venous blood after tissue extraction; values below 60% suggest increased oxygen extraction or reduced delivery.
Question 4: A patient has CO 2.5 L/min, HR 110 bpm. What is the stroke volume?
- 17 mL
- 23 mL (Correct answer)
- 275 mL
- 44 mL
Correct answer: 23 mL
Stroke volume = CO / HR = 2500 mL/min ÷ 110 bpm ≈ 23 mL, which is severely reduced (normal ~70 mL).
Question 5: Which non-invasive technique uses changes in thoracic electrical impedance to estimate cardiac output?
- Thermodilution
- Impedance cardiography (Correct answer)
- Pulse oximetry
- Echocardiographic Doppler
Correct answer: Impedance cardiography
Impedance cardiography (bioimpedance) measures changes in thoracic electrical resistance caused by aortic blood flow to non-invasively estimate cardiac output.
Question 6: Afterload is best represented clinically by:
- Preload (PCWP)
- Systemic vascular resistance (SVR) (Correct answer)
- Stroke volume
- Central venous pressure
Correct answer: Systemic vascular resistance (SVR)
Afterload is the resistance the ventricle must overcome to eject blood; clinically it is best represented by systemic vascular resistance.
Question 7: Elevated PCWP with normal CO and normal SVR is most consistent with:
- Hypovolemic shock
- Diastolic dysfunction / isolated LV filling abnormality (Correct answer)
- Distributive shock
- Right ventricular infarction
Correct answer: Diastolic dysfunction / isolated LV filling abnormality
High PCWP with preserved cardiac output and normal SVR suggests diastolic dysfunction, where the stiff ventricle requires higher filling pressures to maintain output.
CSC Hemodynamic Monitoring & Assessment 2
Cardiac index is calculated by dividing cardiac output by: