Early Predictive Value Of The Urinary Lactate To Creatinine Ratio For Subsequent Development Of HIE In Full-term Asphyxiated Neonates

Background and Objectives: Perinatal asphyxia is a common cause of neonatal morbidity and mortality and neurologic disabilities among survivors. Hypoxic-ischemic encephalopathy (HIE) develops in one third of asphyxiated infants. Neuroprotective interventions are increasingly in the forefront of interest and have been shown to be effective in animal models. It is important to identify infants at high risk for HIE soon after birth .Various scoring systems based on clinical data also proved to be limited prediction rates .In recent years, highly accurate predictions were reported using advanced techniques such as cerebral function minitorization ,magnetic resonance spectroscopy. Nevertheless, those are costly ,and far from being widely available, especially in the basic units. To find widely available , inexpensive, and non-invasive parameters, we measured the ratio of urinary lactate to creatinine(L/C), and determined the sensitivity and specificity of the ratio of L/C for the early prediction of neonates in whom HIE is likely to develop and those who will have a severe adverse outcomes [classified as developmental quotient (DQ)<80 at 6 months].Methods: We examined the ratio of L/C in urine by biochemical methods within 6 hours after birth in 31 normal infants and 72 asphyxiated neonates(further divided into the HIE and the simple asphyxia groups in which the neonates without HIE).At the 14th day after birth ,20-item neonatal behavioral neurological assessment(NBNA) was taken for each asphyxiated infant. The results were correlated with the subsequent presence or absence of HIE and the DQ values (Taken for each HIE subject at 6 months of age).Results : HIE did not develop in any of the normal infants but did develop in 31 of the 72 neonates with asphyxia .Within 6 hours after birth, themean( SD)ratio of urinary L/C was 3.38 4.20 in the HIE groups -a value that was 109 times as high as the ratio in the normal infants (0.031 0.008,.P<0.001)and 37 times as high as that in the simple asphyxia groups (0.091 0.025,P<0.001).A ratio of 0.22, or higher had a sensitivity of 96.8 percent and a specificity of 100 percent for predicting the development of HIE. There were significant differences in the ratios among the mild, the moderate and the severe HIE groups (P<0.001).The ratio of urinary L/C was negatively correlated with the score of NBNA(r=-0.965,P<0.001).The mean ratio of urinary L/Cwas siginficantly higher in the HIE neonates who had adverse outcomes at 6 months (8.28 5.05) than those with favorable outcomesConclusions: Our study shows that determination of urinary L/C ratio soon after birth in asphyxiated infants could be used to identify or predict the development of HIE. Our methods are readily available, inexpensive, and non-invasive and could be widely used in basic hospitals.