Neonatal respiratory distress: changes over 30 years in a geographically defined population

Objective: To document trends in the incidence of respiratory distress (RD), related interventions and mortality in neonates in a geographically defined population over 30 years.

Method: RD was defined as the presence of at least 2 of the following symptoms persisting for 15 minutes or more: tachypnea >60/min, central cyanosis in room air, nasal flaring, retractions and expiratory grunting. In 1974, 1984, 1994 and 2004 a questionnaire was sent to all neonatal units in Switzerland to collect information about the number of infants admitted, infants with RD, needing surfactant, mechanical ventilation or CPAP and mortality.

Results: In the three decades the proportion of infants with RD increased from 1.8% to 3.9% of the whole neonatal population and from 30% to 50% of all infants admitted to a neonatal unit.

The proportion of infants with hyaline membrane disease (HMD) remained stable around 0.5% or 10% of admissions. Treatment of RD changed significantly from 1974 to 2004: Mechanical ventilation decreased from 30% to 15%, nasal CPAP increased from almost 0% to 50% and surfactant administration increased from 0% to 11% in all infants admitted to hospital and from 0% to 53% in infants with hyaline membrane disease. Mortality decreased in infants with RD from 15% to 3%.

Conclusion: The introduction of efficient means to prevent and control RD in neonates such as prenatal steroids, surfactant and nasal CPAP could stabilize the incidence of HMD, but not avoid an increase of RD due to other causes.