Advances in newborn intensive care have lead to dramatic improvements in survival for the most premature infants—often weighing 1 pound at birth. Unfortunately, cerebral palsy, mental retardation, and developmental delay affect more than 10,000 of these premature infants in the U.S. annually. In his studies, Dr. Jeffrey R. Kaiser is trying to understand why these premature infants are at such high risk of brain injury, and to learn ways to prevent injury. Experts believe that disturbances of brain blood flow regulation are important in causing these injuries. Using a novel continuous monitoring system, Dr. Kaiser is able to determine an infant's capacity for normal brain blood flow regulation. Contrary to previous thinking, he has shown that many of these babies in fact due have normal regulation of their brain blood flow. He has observed that brain blood flow may be disturbed during suctioning of the breathing tube. Further, he has also shown that infants with high carbon dioxide, those not breathing well, have impaired regulation of their brain blood flow. Thus, even stable infants are prone to disturbed brain regulation during routine intensive care, which may lead to bleeding in the brain and long-term neurologic problems. Dr. Kaiser will study up to 200 infants to determine 1) the developmental pattern of normal regulation of cerebral blood flow; 2) in those with impaired regulation, determine when it develops during the first week of life; and 3) determine the relationship between impaired brain blood flow regulation and brain injury. Results from this study will help us recognize when premature infants are most vulnerable to developing brain injury, allowing prevention and intervention strategies to be initiated in a timely fashion.