Continuous measurement of cardiac output by inert gas throughflow: comparison with thermodilution.

Objective: The throughflow method is a new technique for continuous and minimally invasive measurement of cardiac output by the Fick principle, which uses ventilation of the 2 lungs with unequal inspired gas concentrations by means of a double-lumen endobronchial tube. It exploits steady-state gas exchange and thus permits rapid repetition of measurement.

Design: Comparison of paired measurements by the throughflow method using N(2)O exchange with bolus thermodilution.