Principles of Measurement and Parameters
Page B-2
Operator’s Manual PiCCO
2
Version 3.1
2
Transpulmonary Thermodilution Technique
2.1
Principle
To accomplish thermodilution determination a known volume of a suitable indicator (at least 10°C below blood
temperature) is injected intravenously as quickly as possible. The recorded downstream temperature change
is dependent on the flow and the volume through which the cold indicator has passed. As a result, a
thermodilution curve can be recorded. The PiCCO
2
detects the cold indicator in the arterial system (preferably
in the femoral artery).
Figure 1: Heart-lung circulation and resulting thermodilution curve
2.2
Transpulmonary Cardiac Output
Cardiac Output (CO) is the volume of blood being pumped by the heart in one minute.
Cardiac output by thermodilution is calculated according to the Stewart-Hamilton formula (see Appendix)
using the area under the thermodilution curve.
Absolute Parameters
Indexed Parameters
Parameter
Abbr.
Unit
Abbr.
Unit
Cardiac output, transpulmonary
CO
l/min
CI
l/min/m
2
