Non-invasive ventilation was among the earliest forms of respiratory support used in infants with respiratory failure in the early seventies.1 Its use in preterm infants, however, subsided to the use of nasal continuous positive airway pressure (N-CPAP). Continuous distending pressure provided by N-CPAP improves oxygenation by stabilising lung volume in infants with respiratory distress syndrome (RDS), reduces apnoea of prematurity and attenuates distortion of the chest wall during inspiration. The use of N-CPAP as a primary mode of respiratory support to avoid invasive ventilation and facilitate weaning from the ventilator has become standard practice. Although successful in a large proportion of infants, N-CPAP is not always effective in avoiding the need for intubation or preventing extubation failure.2–5 This is most evident in the more immature infants who are the ones at a higher risk of developing complications associated with invasive mechanical ventilation.

Nasal intermittent positive pressure ventilation (N-IPPV) is being increasingly used in preterm infants with respiratory failure in lieu of or to facilitate removal from invasive mechanical ventilation. N-IPPV consisting of positive pressure cycles delivered on top of the continuous distending pressure delivered by N-CPAP is used as an intermediate mode of respiratory support between N-CPAP and invasive mechanical ventilation.

Several investigations have explored the physiological and clinical effects of N-IPPV in preterm infants. This manuscript describes the evidence provided by these studies and discusses the areas where further research is needed.

Physiological effects

The proposed mechanisms by which N-IPPV may enhance the support provided by N-CPAP include increased ventilation, higher mean airway pressure, washout of the upper airway anatomical dead space and a possible stimulatory effect of intermittent cycling on the respiratory drive.

Although it is difficult to determine what portion of the positive pressure is transmitted to the distal airways during N-IPPV, physiological data from studies involving …