Cardiac output measurement

Cardiac output measurement has become increasingly important in anaesthesia and critical care, particularly with the growing emphasis on perioperative medicine. Flow cannot be measured by any direct means and therefore models are employed to deduce useful information from other parameters. Numerous techniques are available, each with advantages and disadvantages in terms of invasiveness and validity. Often a balance is struck between invasiveness and validity of the measurements, with acceptance of trends monitoring in some cases, rather than absolute values of cardiac output.