Intraoperative assessment of the Lawrence 3000 Doppler Cardiac Output Monitor.

Transoesophageal Doppler cardiac output measurement was evaluated against the thermodilution method in eleven patients undergoing elective cardiac surgery. A total of 106 pairs of Doppler and thermodilution values were obtained. Cardiac output was measured over a range of 2.3 l.min-1. to 11.51 l.min-1. The mean difference between the Doppler and thermodilution measures was -1.0 l.min-1 (thermodilution minus Doppler). Standard deviction was 1.8 l.min-1. This is a significant difference. It is concluded that these techniques do not agree when measuring cardiac outputs.