This is the first of a two-part series that reviews advanced critical care echocardiography (CCE) techniques designed for critical care physicians. In this section, we review training in basic and advanced CCE. This is followed by a review of Doppler principles, including pulsed wave, continuous wave, and color flow Doppler. Included are Doppler measurement techniques that are useful for assessing the patient with cardiopulmonary failure and the common pitfalls of Doppler. This section ends with a review of the quantitative and semiquantitative measurements of stroke volume, as well as problems with measurement of stroke volume in the ICU and its useful clinical applications. Video-based examples will help demonstrate the techniques that are described in the text.