Bedside assessment of myocardial performance in the critically ill.

No measurement of myocardial performance currently available in the ICU can be regarded is ideal. Table 2 summarises the main features of the major monitoring techniques. As many of the indices of myocardial performance are interdependent, quantifying the contribution of each component to overall cardiac function is not possible currently, and the clinical utility of monitoring each individually is not therefore established. Bedside measurements of LV dimensions, volumes and ejection fraction, and the other indices of systolic and diastolic function can now be made, but the case for their routine use in influencing clinical practice remains unproven. Transoesophageal echocardiography has an important and established diagnostic role and has been used successfully for continuous monitoring during surgery, but practical considerations seriously limit its potential for routine use. Radionuclide techniques allow the measurement of many of the same parameters and have the potential for continuous use, but practical problems and the additional risk of radiation exposure may limit this application in the critical care environment. Doppler techniques are non-invasive, provide continuous data and are simple to operate, but the data provided has important limitations. Although the pulmonary artery catheter has been in use for over twenty years, questions regarding the information is provides concerning myocardial function remain and the extent to which it should influence therapeutic decisions is still controversial. However with the development of additional facilities, particularly the continuous measurement of cardiac output the pulmonary artery catheter seems likely to remain the mainstay of bedside monitoring of myocardial performance in the critically ill in the immediate future.