Spontaneous respiratory effort during mechanical ventilation in infants with and without acute respiratory distress.

Respiratory interactions of 27 ventilated preterm infants were recorded daily during the first 14 days of life to assess the effect on respiratory efforts of recovery from acute respiratory distress syndrome (RDS). Active expiration and persistent asynchrony only occurred during acute RDS (P less than 0.01). Throughout the 14-day period, in the majority of infants making respiratory efforts, a ventilator rate could be found from a standard sequence 30, 60, 90, 120 breaths/min which provoked a synchronous interaction, but with increasing postnatal age apnoea became more common (P less than 0.01). We conclude that the preterm infants' spontaneous respiratory efforts are a less important influence on the outcome of mechanical ventilation following recovery from acute RDS.