Free oxygen radicals--predictors of neonatal outcome following perinatal asphyxia

The study was undertaken to evaluate the role of free oxygen radicals in asphyxiated neonates. Thirty term neonates appropriate for gestational age and with severe birth asphyxia (Apgar score of 3 or less at 1 minute of life) formed the study subjects. The levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), creatine phosphokinase (CPK) and lipid peroxidase (LPO) in the CSF of these neonates were estimated between 12 and 48 hrs of life. Enzyme estimation was performed by standard methods and the results were analysed statistically using Multivariate Logistic Regression analysis and non parametric tests namely Kruskal Wallis test and Wilcoxon's rank sum test. Out of the thirty babies, 14 were observed to be neurologically normal, 9 had significant morbidity and 7 died. The SOD levels ranged from 12.4 to 140 units/ml, GPx from 128 to 1933 nmol/min/dl, CPK from 2 to 2098 IU/dl and LPO from 5.4 to 30.8 umol/hr/dl. The SOD and GPx levels had an inverse relationship whereas rise in LPO and CPK levels were directly proportional to the extent of neurological damage and ultimate clinical outcome. CPK levels higher than 140 IU/ml were lethal and associated with 100% mortality whereas all normal neonates had CPK below 37 IU/ml. The levels of antioxidant enzymes can reliably and significantly predict mortality and morbidity whereas level of an enzyme cannot confidently confer normalcy. Hence antioxidant enzyme levels with a cut off value can be a useful marker and serve as a prognostic indicator in times to come.