ATRIAL NATRIOURETIC FACTOR (ANF) PLASMA LEVELS IN NEONATES TREATED WITH MULTIPLE DOSES OF SURFACTANT(S)

Abstract

In order to test the hypothesis that changes in pulmonary compliance affect ANF levels, we measured the concentrations of ANF sequentially in 24 neonates. All infants were mechanically ventilated for severe HMD and received multiple doses (3-5) of porcine S (Curosurf). The BW was 1654±570gr (mean ±SD) and the GA 31±2.8 weeks. ANF concentrations were high on day 1 (206±198pgr/ml) before S administration, but decreased on day 2(192±123pgr/ml), in contrast to statistically significant elevations seen in neonates with HMD not treated or treated with a single dose of S.ANF further declined on day 4(93±82pgr/ml). There were not significant differences in ANF levels between neonates receiving high (600mg/kgr) and low (300ng/kgr)doses of S. Our results suggest that as lung compliance increased, after S administration,intrathoracic pressure increased, thereby decreasing venus return, atrial strech and ANF secretion. Before S administration, the ANF concentrations increased from a level of 98pgr/ml 1-2hours after birth to a maximum of 426 pgr/ml at the age of 12-24hours, as seen by others. Factors associated with higher ANF levels were the presence of PDA, and water retention (p<.05). However, we were unable to detect any significant correlation between ANF levels and creatinine clearance, FeNa, RFI or ratio water intake to urine output in this population.