Cerebral Doppler sonography of the neonate. A résumé after 20 years and future aspects.

Up until recently the evaluation of CVR (analysis of pulsatility) had been a priority in Doppler sonography. In preterm and term infants with open fontanels and sutures this information is restricted despite its value in extreme situations. Continuous Doppler sonography allows a new approach to monitoring pathophysiologic processes. In connection with improved data recording and processing as well as progress in monitoring blood pressure and central venous pressure, new noninvasive methods of surveillance become possible. Thanks to these methods experimental and clinical research has increasingly gained insight on the autonomic nervous system over the last few years (e.g., m- and r-wave analysis during continuous measurement of arterial blood pressure and heart rate). Already well-known and newly developed functional tests (e.g., tilting test, CO2-reactivity, phase shift, and so forth) will further improve our understanding of physiologic processes and help us develop individual therapy concepts for the newborn.