Holding breath

The physical properties of surfactant were identified in the early 1950s from research on warfare chemicals by Pattle in Britain and by Radford and Clements in the US. The causal relationship between respiratory distress syndrome and surfactant deficiency was established in Boston by Avery and Mead in 1959. The Australian obstetrician Liggins induced lung maturity with glucocorticoids in 1972, but his discovery was not fully accepted for another 20 years. When the major surfactant compound was identified as dipalmitoyl-phosphatidylcholine, this substance was nebulized with little effect and it became clear that there were other components of natural surfactant required besides phospholipids. A century of basic research was rewarded when Fujiwara introduced bovine surfactant substitution in Japan in 1980 to treat and prevent respiratory distress syndrome in preterm infants. Surfactant substitution greatly alleviated respiratory distress syndrome and increased the preterm infant’s chance of survival. In addition, it has set high scientific standards for the introduction of new therapies for neonates and made the randomized multicentre trial the favoured tool for clinical innovations.

Association Between Neonatal Care Practices and Efficacy of Exogenous Human Surfactant: Results of a Bicenter Randomized Trial

The purpose of this study was to analyze the impact of neonatal care practices on the efficacy of exogenous human surfactant. Two hundred newborns (gestational age 24.0 to 29.9 weeks, lecithin-sphingomyelin ratio less than 2 or absent phosphatidylglycerol, and requirement of mechanical ventilation at birth) participated in a randomized bicenter trial of human surfactant substitution. In only one of the two sites (site 2) surfactant substitution decreased the severity of respiratory failure and increased neonatal survival without bronchopulmonary dysplasia. For analysis of three-way association, continuous variables describing patient characteristics and treatment were dichotomized at the median. The following variables were significantly associated with good outcome in site 1 and 2 and with surfactant substitution in site 2: low oxygen requirement during first three neonatal days, low mean airway pressure during second and third day, low Paco2 during first two neonatal days, and no ligation of ductus arteriosus. Low fluid intake during the first three days and low colloid intake during the first two days of life were associated with good outcome in both sites. The ratio between mean airway pressure and the oxygen requirement was higher in site 2 than in site 1 during the first day of life. Fluid intake and ventilatory management may influence the efficacy of exogenous surfactant.