Cardiac Output by Thermodilution (Fick Principle) Calculator
Calculates cardiac output, cardiac index, and stroke volume from invasive haemodynamic measurements. Uses the Fick principle (O2 consumption) or thermodilution (Swan-Ganz catheter).
Score interpretation
CI < 2.2 -- cardiogenic shock or severely reduced output; haemodynamic support required
→ Cardiogenic shock management: vasopressors (noradrenaline first-line: 0.1-1 mcg/kg/min); inotropes (dobutamine 2.5-20 mcg/kg/min or milrinone 0.375-0.75 mcg/kg/min) if low CO persists; avoid excessive noradrenaline (worsens afterload); mechanical circulatory support: IABP (augments diastolic pressure, reduces afterload), Impella (axial flow pump), VA-ECMO (full cardiopulmonary support); fluid challenge only if preload responsive (PCWP < 15 mmHg); target CI > 2.2 L/min/m2; mixed venous O2 saturation (SvO2) target > 65%; ICU level care; cardiology/cardiac surgery team review.
CI 2.2-2.4 -- borderline cardiac output; monitor closely and optimise
→ Close haemodynamic monitoring; optimise preload (PCWP target 15-18 mmHg for failing ventricle); rate control (HR 60-90 bpm optimal for CO); vasodilators if afterload elevated (systemic vascular resistance > 1200 dyn.sec.cm-5): GTN infusion or nitroprusside; inodilator (levosimendan or milrinone) if low CO + high filling pressures; daily fluid balance; daily echo for LV function; SGLT2 inhibitor if HFrEF (EMPEROR-Reduced, DAPA-HF); diuretics for decongestion.
CI >= 2.5 -- adequate cardiac output; haemodynamic stability maintained
→ Continue monitoring; ensure haemodynamic targets met: MAP > 65 mmHg, ScvO2/SvO2 > 70%; vasopressor/inotrope weaning if on support; target CI 2.8-3.5 L/min/m2 in severe sepsis/distributive shock (high CO state); wean monitoring lines when haemodynamically stable > 24-48 hours; reassess clinically (end-organ perfusion: mental status, urine output, skin perfusion, lactate); echocardiographic correlation.
Interpretation bands for the CO Thermodilution. Apply clinical judgement and local guidance.
References
- Forsberg S et al. Cardiac output measurement methods. Acta Anaesthesiol Scand. 2022;66(2):163-173.
- Vincent JL et al. The pulmonary artery catheter consensus statement. Crit Care Med. 2003;31(10):2803-2809.
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
- Aspirin (Loading Dose) · Antiplatelet — ACS / Ischaemic Stroke
- Alteplase (tPA) · Thrombolytic — Ischaemic Stroke / Massive PE
- Gelatin (succinylated) · Colloid plasma volume expander
- 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.