Date:
Sep 01, 1999

A large proportion of full term or nearly full term infants who have oxygen supply difficulties at the time of birth (perinatal hypoxia) demonstrate no indication of developmental brain damage. However a small proportion of them will subsequently demonstrate brain damage (e.g. cerebral palsy). At the time of birth or shortly thereafter, there are no reliable methods for indicating which hypoxic newborns are in danger of developing brain damage. It is important to be able to identify newborns at risk of brain damage as soon as possible if interventions are to be used early enough to safeguard the threatened developing brain.

A recent research paper1 describes the results of a chemical analysis of the newborn’s urine that had oxygen insufficiency during the birthing period. Studies of urine taken within 6 hours of birth were very indicative of the danger of the infant developing brain damage. The urine was tested for two products of energy metabolism, lactate and creatine.

Comment:

About 25% of full term infants who demonstrated signs of fetal distress during birthing (the perinatal period) subsequently develop developmental brain damage; the other 75% do not. How to tell them apart so as to take advantage of the window of opportunity in which an intervention (e.g. cooling) might protect the threatened brain? Most clinical evaluations and laboratory tests presently available have been poor predictors. The report summarized above would seem to be a valuable tool for helping to make that prediction.

However, having identified the newborn at risk of developmental brain damage, the remaining issue is how to protect the infants brain–neuroprotection. The methods presently available are still far from satisfactory. A number of experimental drugs have not worked out; head cooling is again being evaluated; increased oxygen is also again being considered but its potential usefulness is clouded by its sometimes disastrous side effects. Entirely new approaches to the repair of the brain injury are being explored and their very early use may prove effective.

Despite the above, being able to identify the newborn at risk is an important step forward. The success of this laboratory evaluation will undoubtedly lead to even more accurate means of making this assessment. It also opens up possibilities to far better understand what is happening in the threatened brain and thus what might be done to protect it.

1 Huang, C-C et al. Measurement of the Urinary Lactate-Creatinine Ratio for the Early Identification of Newborn/Infants at Risk for Hypoxic-Ischemic Encephalapathy. NEJM 1999; 341:328-335
© UCP Research & Educational Foundation, September 1999