Low antithrombin III: accurate predictor of idiopathic respiratory distress syndrome in premature neonates.

A prospective study was performed in premature neonates to determine the predictive values of antithrombin III (AT III) deficiency immediately after birth, for the subsequent development of idiopathic respiratory distress syndrome (IRDS), intraventricular haemorrhage (IVH) and death. Of the 81 premature infants studied, 24 developed IRDS (30%). Of these 24 premature infants, 8 also developed IVH and 9 infants died within the follow-up period of 7 days. The mean plasma AT III level was significantly lower in the infants developing IRDS (0.23 U/ml vs 0.35 U/ml, P less than 0.0005). Within this study group 33 neonates of less than 30 weeks' gestation showed a prevalence for IRDS of 48%. In this group, AT III activity levels below 0.30 U/ml were 8.5 times as likely to result from infants with IRDS than from infants without IRDS. The diagnostic accuracy indices of criteria for the development of IRDS were: a sensitivity of 100%, a specificity of 88%, a positive predictive value of 89% and a negative predictive value of 100%. The predictive values for the development of IVH and occurrence of death were insignificant. Therefore, in premature neonates the combination of less than 30 weeks' gestation and an AT III below 0.30 U/ml is highly suggestive of IRDS and may facilitate the evaluation of early treatment.