The Doppler ultrasound: A bedside tool to understand cerebral autoregulation in neonates

Cerebral blood flow is a unique circulation in the human body, constituting around 15% of cardiac output with the brain comprising 2% of the total body weight. The cerebral autoregulation is maintained physiologically to keep the oxygen extraction constant from the brain cells. There are different ways to measure cerebral circulation, including near-infrared spectroscopy and diffuse optical spectroscopy. The limitation of using such equipment is because of the cost and nonavailability. The bedside Doppler ultrasound because of its easy availability it is used in the assessment of cerebral blood flow. There are many factors that contribute to cerebral blood flow. Understanding the variation in the cerebral blood flow by calculating the resistive index of play in the cerebral vessels will help the physician to understand the autoregulation – compensated or uncompensated.