Initial systolic time intervals as predictors of the severity of transient tachypnea in term neonates.

42 term neonates with transient tachypnea (TTN) underwent echocardiography and determination of systolic time intervals before the age of 4 hours. Based on initial measurement of right ventricular systolic time intervals (RVSTIs) the patients were divided in two groups: neonates with RVSTI ratios less than or equal to 0.50 (Group I) (n = 35) and neonates with RVSTI ratios greater than 0.50 (Group II) (n = 7). Group II neonates also had significantly more prolonged left ventricular systolic time intervals (LVSTIs) than Group I neonates. Group II neonates developed markedly more severe form of TTN than Group I neonates. Initially prolonged RVSTI was best predictor of the development of severe TTN (relative risk ratio 17.5, p less than 0.001): clinical characteristics and oxygen requirements at the admission had limited predictive value.