Hemodynamics · Cath Lab Tools

Cardiac output — Fick

Hgb, weight, and height come from the shared patient. Sats as %.

Arterial sat SaO₂ (%)

Mixed venous SvO₂ (PA, %)

VO₂ estimate (mL/min/m²)

Measured VO₂ (mL/min, overrides)

Thermodilution CO (L/min, optional)

BSA (Mosteller)

— m²

Fick CO

— L/min

CO in use · —

— L/min

Cardiac index

— L/min/m²

Fick CO = VO₂ ÷ (1.36 × Hgb × 10 × (SaO₂ − SvO₂)). VO₂ estimated at 125 mL/min/m² unless measured (consider ~110 in elderly). Thermodilution, if entered, is used for downstream calculations. CI normal 2.5–4.0; <2.2 with congestion suggests cardiogenic shock.

Resistances & PH assessment

Uses CO from above.

Systemic BP (mmHg)

RA mean (mmHg)

PA pressure (mmHg)

PCWP mean (mmHg)

SVR

— dyn·s·cm⁻⁵

PVR

— WU

TPG / DPG

— mmHg

SVR normal 800–1200 dyn·s·cm⁻⁵ (10–15 WU); PVR normal <2 WU. PH = mPAP > 20 mmHg: pre-capillary if PCWP ≤ 15 & PVR > 2 WU; isolated post-capillary if PCWP > 15 & PVR ≤ 2; combined if both elevated (ESC/ERS 2022 definitions).

Valve area — Gorlin & Hakki

Uses CO from above.

Valve

Mean gradient (mmHg)

Heart rate (bpm)

SEP (s/beat)

Gorlin

— cm²

Hakki (CO ÷ √ΔP)

— cm²

SEP = systolic ejection period (aortic); DFP = diastolic filling period (mitral), in seconds per beat. Severe AS: AVA < 1.0 cm² (mean ΔP ≥ 40); severe MS: MVA ≤ 1.5 cm². Gorlin underestimates area in low-flow states.

Shunt run — Qp:Qs

Enter sats (%). Mixed venous auto-computes from SVC/IVC (Flamm) or enter directly.

SVC sat

IVC sat

Mixed venous (auto Flamm)

PA sat

PV sat (or SaO₂ if no R→L)

Aortic / LV sat

— Qp : Qs

Qp:Qs = (SaO₂ − MV) ÷ (PV − PA). Flamm MV = (3×SVC + IVC)/4. Significant O₂ step-up: ≥7% at atrial level, ≥5% at ventricular/PA level. Qp:Qs ≥ 1.5 generally significant L→R; <1.0 suggests net R→L.