Utility of the rapid B-type natriuretic peptide assay for detection of cardiovascular problems in newborn infants with respiratory difficulties

Background: Because the major problems of respiratory difficulties in newborn infants are due to cardiopulmonary problems, improving the early detection and referral of newborn infants with cardiovascular problems has been considered one of the primary goals of care in the neonatal intensive care unit. Objective: To evaluate whether rapid plasma B-type natriuretic peptide (BNP) assay could be used as a screening test to detect the cardiovascular problems in newborn infants with respiratory difficulties. Methods: We studied 73 newborn infants ≥34 weeks gestational age presenting with respiratory difficulties during the first few days after birth; they were divided into a cardiovascular problem group (CP group, n = 32) and a noncardiac problem group (NP group, n = 41) according to the presence of cardiovascular problems by clinical and/or echocardiographic studies in newborn infants with respiratory difficulties. Results: On admission, the median (25-75%) BNP concentration of the CP group was significantly higher than that of the NP group [1,038 (578-1,435) vs. 240 (118-388) pg/ml, p < 0.001]. The best cutoff BNP values for differentiating the CP group were 346.0, 421.0, 570.5 and 191.5 pg/ml within 18 h, at 18-36 h, at 36-60 h and after 60 h of life, respectively. Although the plasma BNP measurement was not a single confirmative test, it was found to have a high sensitivity and a high negative predictive value for rapidly ruling out serious cardiovascular problems in neonatal respiratory difficulties. Conclusion: A rapid plasma BNP assay may be useful for detection of cardiovascular problems in newborn infants with respiratory difficulties during the first few days after birth.