CCS CCS Hemodynamics & Cardiac Monitoring 1 — Questions and Answers
Question 1: Normal cardiac output (CO) in a resting adult is approximately:
- 1–2 L/min
- 2–3 L/min
- 4–8 L/min (Correct answer)
- 10–12 L/min
Correct answer: 4–8 L/min
Normal resting cardiac output is 4–8 L/min, calculated as heart rate multiplied by stroke volume.
Question 2: Which hemodynamic parameter best reflects left ventricular preload?
- Pulmonary artery wedge pressure (PAWP) (Correct answer)
- Systemic vascular resistance (SVR)
- Cardiac index (CI)
- Mean arterial pressure (MAP)
Correct answer: Pulmonary artery wedge pressure (PAWP)
Pulmonary artery wedge pressure (PAWP) reflects left atrial pressure and is the best bedside estimate of left ventricular end-diastolic pressure (preload).
Question 3: A patient's arterial waveform shows pulsus paradoxus greater than 10 mmHg. This finding is most consistent with:
- Aortic stenosis
- Cardiac tamponade (Correct answer)
- Mitral regurgitation
- Hypertrophic cardiomyopathy
Correct answer: Cardiac tamponade
Pulsus paradoxus >10 mmHg is a classic sign of cardiac tamponade, caused by exaggerated respiratory variation in ventricular filling due to pericardial constraint.
Question 4: Mean arterial pressure (MAP) is calculated using which formula?
- MAP = (SBP + DBP) / 2
- MAP = DBP + 1/3 (SBP – DBP) (Correct answer)
- MAP = SBP – DBP
- MAP = CO × SVR / 80
Correct answer: MAP = DBP + 1/3 (SBP – DBP)
MAP = DBP + 1/3 (pulse pressure), reflecting that diastole comprises approximately two-thirds of the cardiac cycle.
Question 5: Elevated systemic vascular resistance (SVR) in a patient with low cardiac output most likely indicates:
- Septic shock
- Cardiogenic shock (Correct answer)
- Anaphylactic shock
- Distributive shock
Correct answer: Cardiogenic shock
Cardiogenic shock presents with low CO and high SVR (compensatory vasoconstriction), distinguishing it from distributive shock where SVR is low.
Question 6: Which waveform component on a pulmonary artery catheter tracing represents atrial contraction?
- a wave (Correct answer)
- c wave
- v wave
- x descent
Correct answer: a wave
The 'a' wave on the CVP or PAWP tracing corresponds to atrial contraction and the resulting rise in atrial pressure.
CCS CCS Hemodynamics & Cardiac Monitoring 1
Normal cardiac output (CO) in a resting adult is approximately: