Cardiac output monitoring for nursing practice and exams. Thermodilution technique, Fick principle, non-invasive CO estimation, cardiac index interpretation, and clinical application in ICU hemodynamic management.
Principle: Cold saline injected into RA; temperature change measured at PA thermistor. CO inversely proportional to temperature change area.
Values: 4–8 L/min; average 3 measurements for accuracy
Limitations: Errors: injection technique, timing to respiration, tricuspid regurgitation, intracardiac shunts
Principle: CO = VO2 / (CaO2 − CvO2). Uses measured oxygen consumption and arteriovenous O2 difference. Most accurate in steady state.
Values: Same targets as thermodilution; most accurate with direct VO2 measurement
Limitations: Requires arterial and PA blood sampling; assumed VO2 introduces error
Principle: PiCCO (pulse contour analysis + transpulmonary thermodilution), FloTrac/Vigileo (arterial waveform analysis), bioreactance (NICOM), echocardiography.
Values: Validated against thermodilution in hemodynamically stable patients
Limitations: Accuracy reduced in arrhythmias, high vasopressor requirements, poor A-line quality
CI = CO ÷ BSA (normal: 2.5–4.0 L/min/m²)
Cardiac index corrects for body surface area. A CO of 4 L/min is adequate for a 50 kg patient but inadequate for a 100 kg patient. CI <2.2 L/min/m² with signs of hypoperfusion defines cardiogenic shock.
Hemodynamics Fundamentals
Preload, afterload, MAP, shock (included with RN/NP)
Advanced Hemodynamics
Swan-Ganz, SVR, PAOP, ICU simulations ($149 add-on)
Pulmonary Artery Catheter
Swan-Ganz waveforms and parameters
Shock & Perfusion
Apply CO data to shock management
