BLOOD GLUTATHIONE REDOX RATIO AS A PARAMETER OF OXIDATIVE STRESS IN PREMATURE-INFANTS WITH IRDS

Oxygen toxicity is thought to play an important pathogenic role in sev eral neonatal diseases, including idiopathic respiratory distress synd rome (IRDS). Therefore, the development of a reliable measure of the a ctual oxidative stress status of patients would be of great clinical s ignificance. In order to obtain information about the oxidative stress during the first week of life in premature infants with IRDS, the blo od concentrations of oxidized and reduced glutathione, as well as thei r molar ratios, were determined by a highly sensitive, specific enzymi c assay: The fractional inspired oxygen concentrations needed to maint ain adequat arterial oxygen tension and the arterio-alveolar oxygen ra tios were chosen as parameters indicating the severity of illness in p remature infants at a given time. There was a highly significant posit ive correlation between the glutathione redox ratios and the fractiona l inspired oxygen concentrations. A maturity-related difference was al so found; the oxidized glutathione concentrations were the highest in the least mature infants, accompanied by a pronounced compensatory ris e in the reduced glutathione concentrations as well. A significant neg ative correlation was found between the arterio-alveolar oxygen ratio and the glutathione redox ratio: i.e., an improvement in oxygenation w as accompanied by a decrease in the glutathione redox ratio. The effic ient recycling of reduced glutathione in erythrocytes providing antiox idant protection for premature infants, permits the use of the blood g lutathione redox ratio as a noninvasive measure of in vivo oxidative s tress.