Swan-Ganz Cath

Swan-Ganz Calculator
INPUTS Invasive Hemodynamics OUTPUT Units Normal Values
MAP
 Cardiac Output (CO) -- L/min 4-6 L/min
SpO2
 Cardiac Index (CI) -- L/min/m^2 2-4 L/min/m^2
ScvO2
 SvO2 (%) -- % 65-75%
Hgb
 SaO2 (%) -- % 94-100%
BSA
 SVR -- (dynes*sec/cm^5) 900-1400 dynes*sec/cm^5
ABPs
 PVR -- Woods Units <2.8 Woods Units
ABPd
 RA (Mean) -- mmHg 1-6 mmHg
ABPm
 PA (S/D/Mean) -- mmHg 25/10/15 mmHg
PAPs
 PCWP (Mean) -- mmHg 6-11 mmHg
PAPd
 AO (S/D/Mean) -- mmHg mean >60 mmHg
PAPm
 CPO -- W If <0.6, LV failure
PAWP
 PAPI -- If <0.9, RV failure
CVP

Swan Interpretation

Pattern CVP PCWP CI SVR PVR PAPI CPO
Right HF ↑ Normal or ↑ ↓ ↑ ↑ <0.9 Normal or ↓
Left HF Normal or ↑ ↑ ↓ ↑ Normal or ↑ Normal or ↓ <0.6
Tamponade ↑ ↑ ↓ ↑ Normal or ↑ ↓ ↓
Hypovolemia ↓ ↓ ↓ ↑ Normal or ↓ Normal or ↑ ↓
Cardiogenic shock ↑ ↑ ↓ ↑ ↑ ↓ ↓
Sepsis / distributive ↓ ↓ ↑ ↓ ↓ or Normal Normal or ↑ Normal or ↑

Swan Basics

CXR Placement

  • Path: SVC → RA → RV → PA → branch
  • Ideal tip: Proximal R/L pulmonary artery, ~3–5 cm beyond carina, near hilum
  • Too proximal: In RV → arrhythmia risk
  • Too distal: In segmental PA → rupture risk

Equations

Cardiac output (CO)

  • CO (L/min) = (125 × BSA) / [(SaO2 − ScvO2) × 1.36 × 10 × Hgb]

Cardiac index (CI)

  • CI (L/min/m²) = CO / BSA

Systemic vascular resistance (SVR)

  • SVR (dynes·sec/cm^5) = 80 × (MAP − CVP) / CO

Pulmonary vascular resistance (PVR)

  • PVR (Wood units) = (PAmean − PCWP) / CO

Cardiac power output (CPO)

  • CPO = (MAP × CO) / 451

Pulmonary artery pulsatility index (PAPI)

  • PAPI = (PAPs − PAPd) / CVP