Title:
Is there a necessity for multiple doses of surfactant for respiratory distress syndrome of premature infants?

Abstract:
Both prophylactic and early surfactant (SF) replacement therapy reduce pulmonary complications and mortality in ventilated infants with respiratory distress syndrome (RDS). The effectiveness of one or more doses and the impact on morbidity and mortality of premature neonates with RDS need to be further clarified. The objective of this study was to investigate the necessity of repeated surfactant replacement therapy in premature infants ≤32 weeks of gestational age and the possibility of an underlying pathology. This study included 126 premature neonates of 24-32 weeks of gestation. We used 200 mg/kg per dose of porcine surfactant (Curosurf®) as primary treatment and 100 mg/kg in cases that required retreatment. The subjects were classified into two groups: the first group (Group 1) received a single dose of surfactant (n=98) and the second group (Group 2) included infants who required more than one dose (n=28). The 1st dose was administered in the first 20 minutes after birth while the second was given six hours later. In four cases, a 3rd dose was required, that was provided 12 hours after birth. Recorded data included: clinical and radiological classification of RDS, extubation time, oxygenation estimation indexes (OI: oxygenation index, A-aDO2: alveolar-arterial oxygen difference, a/APO2: arterial-alveolar ratio of partial oxygen pressure), requirement and duration of oxygen administration, total duration of mechanical ventilation, and survival rate. Patient Group 1 did not present any radiological findings of RDS of grade 3 or 4 six hours after SF administration, whereas such findings were recorded in three neonates of Group 2. Therefore, we assumed that failure of a single-dosing treatment indicates a more severe RDS and might reflect an underlying pathology. The impact of maternal chorioamnionitis in the neonates that necessitated further replacement therapy was statistically significant (p=0.045); moreover, infection markers were positive in the majority of the patient population of the second group. Twenty-two neonates (22%) of the first group needed intubation in the delivery room compared to 16 (57%) of the second group (p=0.0001). In conclusion, premature infants treated with a single dose of surfactant can usually be successfully extubated. Requirement of retreatment could be attributed to other pathogenetic mechanisms. A positive history of maternal chorioamnionitis was the commonest reason.