A 50-year-old man on ICU is monitored with a pulmonary artery catheter. His thermodilution cardiac output measurements are performed using iced saline...

Question

A 50-year-old man on ICU is monitored with a pulmonary artery catheter. His thermodilution cardiac output measurements are performed using iced saline injectate. The first measurement gives CO of 4.0 L/min. However, if the injectate were inadvertently warmer than intended (room temperature instead of iced), how would this affect the measured CO?

Accepted Answer

The measured CO would be falsely elevated - a warmer injectate produces a smaller temperature change (smaller thermodilution curve area), which the computer interprets as a higher cardiac output

Answer

No effect - injectate temperature does not affect the measurement

Answer

The measured CO would be falsely low

Answer

The measurement would be identical regardless of injectate temperature

Answer

Warm injectate is always preferred

uk-fficm MCQ (SBA): PA Catheter - Thermodilution Errors