Nucleated red blood cells and early EEG: predicting Sarnat stage and two year outcome.

AIMS: Hypoxic Ischaemic Encephalopathy (HIE) causes characteristic changes of the electroencephalogram (EEG), and a raised Nucleated Red Blood Cell (NRBC) count compared to controls. We wished to examine whether combining these markers could improve their ability to predict HIE severity in the first 24h.

METHODS

Term infants with HIE were recruited. NRBC count and continuous multi-channel EEG were recorded within the first 24h. Neurological assessment was carried out at 24 months. A control population with NRBC counts in the first 24h was recruited.

RESULTS

44 infants with HIE and 43 control infants were recruited. Of the HIE population 39 completed a 2 year follow-up. The median NRBC count differed significantly between the controls and those with HIE (3/100 WBC [range of 0-11] vs 12.3/100 WBC [0-240]) (p<0.001). Within the HIE population the median NRBC count was significantly greater in infants with moderate/severe HIE than mild (16/100 WBC [range of 0-240] vs 8/100 WBC [1-23]) (p=0.016), and among infants with abnormal outcome compared to normal (21.3/100 WBC [1-239.8] vs 8.3/100 WBC [0-50])(p=0.03). The predictive ability of EEG changed with time post-delivery, therefore results are given at both 12 and 24h of age. At both time points the combined marker had a stronger correlation than EEG alone; with HIE severity (12h: r=0.661 vs r=0.622), (24h: r=0.645 vs r=0.598), and with outcome at 2 years (12h: r=0.756 vs r=0.652), (24h: r=0.802 vs r=0.746).

CONCLUSION

Combining early EEG and NRBC count to predict HIE severity and neurological outcome, improved the predictive ability of either in isolation.