Controlled hypercapnia and neonatal cerebral artery Doppler ultrasound waveforms

Eleven normal term infants undergoing respiratory assessment involving rebreathing to produce progressive hypercapnia were studied by Doppler ultrasound examination of an anterior cerebral artery during the procedure. A linear increase in end tidal carbon dioxide concentration from 4.5% to a maximum of 8.5% was documented during a period of 4-5 min rebreathing. A corresponding elevation of transcutaneous carbon dioxide tension was shown in the two infants monitored in this way. In all cases the Pourcelot index fell with rising end tidal carbon dioxide concentration. This fall in Pourcelot index was due to an increase in the diastolic frequency of the Doppler waveform. These results are consistent with the view that Pourcelot index correlates with cerebral vascular resistance distal to the site of recording

Predictive value of early continuous amplitude integrated EEG recordings on outcome after severe birth asphyxia in full term infants.

The background pattern in single channel amplitude integrated EEG recordings (aEEG) was recorded in 47 infants within the first six hours after birth to see if this could predict outcome after birth asphyxia. The aEEG background pattern during the first six hours of life was continuous and of normal voltage in 26 infants. All these infants survived; 25 were healthy, one had delayed psychomotor development. A continuous but extremely low voltage pattern was present in two infants, both of whom survived with severe handicap. Five infants had flat (mainly isoelectric) tracings during the first six hours of life; four died in the neonatal period, and one survived with severe neurological handicap. Burst-suppression pattern was identified in 14 infants, of whom five died, six survived with severe handicap, and three were healthy at follow up. The type of background pattern recorded within the first six postnatal hours in the aEEG tracings predicted outcome correctly in 43 of 47 (91.5%) infants. Use of aEEG monitoring can predict outcome, with a high degree of accuracy, after birth asphyxia, within the first six hours after birth. The predictive value of a suppression-burst pattern was, however, somewhat lower than the other background patterns. The aEEG seems to be a feasible technique for identifying infants at high risk of subsequent brain damage who might benefit from interventionist treatment after asphyxia