Methods of estimating cardiac output in the field

Simultaneous estimation of cardiac output (CO) by thoracic electrical bioimpedance (TEB) and thermodilution (TD) confirmed the results of a previous study which showed good agreement between these methods in selected, principally non-septic, patients. Poor agreement was found between simultaneous TEB and oesophageal Doppler monitoring (ODM) estimates of baseline and acute changes in CO. Taken with the results of previous studies, this implies that although isolated ODM estimates of CO, which tend to underestimate, are less reliable, ODM is the preferred method to monitor acute changes in CO. For many reasons, not least the speed with which a large number of seriously injured soldiers could be assessed, ODM is probably the better method if a non-invasive estimate of CO is required in field hospitals.