OBJECTIVE: To review the reliability and validity estimates of impedance cardiography to assess its empirical precision and clinical usefulness.
DATA SOURCE: Empirical and theoretical literature mainly within the last 10 years.
DATA SYNTHESIS: Descriptive statistics used to summarize the accuracy and use of impedance cardiography to estimate stroke volume.
CONCLUSIONS: Estimation of cardiac output is presently a core component of optimizing cardiac function in many patient populations. Impedance cardiography, which initially used a formula developed by Kubicek et al. and recently a formula developed by Sramek and Bernstein, remains controversial with regard to its accuracy and use in research and clinical practice.