Cardiac Output (Fick Method)
Calculates cardiac output using the Fick principle: VO₂ divided by arteriovenous O₂ difference.
Score interpretation
Cardiac output < 4.0 L/min: Reduced. Normal range is 4–8 L/min.
→ Assess for cardiogenic shock, tamponade, or severe valvular disease. Consider cardiac index (CO/BSA).
Cardiac output 4–8 L/min: Within normal range.
→ Cardiac index (CI) = CO / BSA. Normal CI 2.5–4.0 L/min/m².
Cardiac output > 8 L/min: Elevated. Consider high-output states.
→ Consider: anaemia, sepsis, hyperthyroidism, AV fistula, liver failure.
Interpretation bands for the CO (Fick). Apply clinical judgement and local guidance.
References
- Fick A. Ueber die Messung des Blutquantums in den Herzventrikeln. Sitzungsberichte der Physikalisch-medizinischen Gesellschaft zu Würzburg. 1870.
Related
Curated clinical cross-links plus same-class fallbacks.
- Lidocaine IV (Cardiac Arrhythmia) · Antiarrhythmic
- Protamine Sulphate (Heparin Reversal) · Heparin Reversal / Cardiac Surgery
- Mavacamten · Cardiac myosin inhibitor
- Digoxin · Cardiac Glycoside
- Aprotinin · Antifibrinolytic — Cardiac Surgery
- Protamine Sulphate · Heparin Antidote — Vascular / Cardiac Surgery
- Acute Heart Failure · ESC 2021 Heart Failure Guidelines; NICE NG106
- NSTEMI / Unstable Angina · ESC 2020 NSTEMI Guidelines; NICE NG185
- New-Onset Atrial Fibrillation · ESC 2020 AF Guidelines; NICE NG196
- Hypertensive Emergency · ESC/ESH 2018 Hypertension Guidelines; NICE NG136
- Bradycardia Management · Resuscitation Council UK ABCDE; ESC 2021 Pacing Guidelines
- Ventricular Tachycardia / Fibrillation · Resuscitation Council UK ACLS; ESC 2022 Ventricular Arrhythmia Guidelines
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.