Pathophysiology of perinatal asphyxia.

Following a severe asphyxial episode many cells can recover metabolically, and a cascade of processes are triggered in which intervention, even some hours later, can allow rescue of some cells that would otherwise die. A number of principles, however, needs to be carefully considered before extrapolating from animal to human trials. In particular, the effects on long-term outcome and on those who are compromised by intrauterine growth retardation need to be determined. It is critical to be able to identify rapidly those infants in terms of nature and severity of injury who are most likely to benefit from treatment. The dimension of time and phase of injury or recovery are key factors to effective intervention. Novel continuous cerebral function monitoring techniques such as those based on real-time spectral analysis of the EEG activity, cortical impedance monitoring, and near-infrared spectroscopy have considerable potential for determining the severity and pathophysiologic phase of injury on line.