It is tried to evaluate if common procedures theorically associated with alteration of the cerebral flow, in extreme premature babies affect the Amplitude- Integrated Electroencephalography record. It will measure up if changes happen to relation to the application of Surfactant, Indomethacin in 3 rate of application and Aminophyline's infusion. The effect of desaturation will measure up, bradycardias and apneas in the extent of voltage.