This method of measuring CO was shown to correlate well with the trend of CO measured using the pulmonary artery catheterisation method7, 8. It has also been shown to correlate well with the echo Doppler during exercise9. Bataille et al (2012) compared the esCCO monitor with transthoracic echocardiography for CO measurement in intensive care patients10. The authors deemed the esCCO to be clinically unacceptable in critically ill patients, although there were questions about the validity of this study11, 12. This is primarily because of extensive vasoconstriction and peripheral shut down with the critically ill septic patients. Use of this device in obstetrics is acceptable.