Despite strong evidence of important benefits of volume-targeted ventilation, many high-risk extremely preterm infants continue to receive traditional pressure-controlled ventilation in the United States and elesewhere. Reluctance to abandon one's comfort zone, lack of suitable equipment and a lack of understanding of the subtleties of volume-targeted ventilation appear to contribute to the relatively slow uptake of volume-targeted ventilation. This review will underscore the benefits of using tidal volume as the primary control variable, to improve clinicians’ understanding of the way volume-targeted ventilation interacts with the awake, breathing infant and to provide information about evidence-based tidal volume targets in various circmstances. Focus on underlying lung pathophysiology, individualized ventilator settings and tidal volume targets are essential to successful use of this approach thereby improving important clinical outcomes.

Two fundamentally different approaches to controlling gas flow during positive pressure ventilation are possible. In pressure-controlled ventilation (PCV), sometimes also referred to as pressure-limited ventilation(PLV), the primary control variable is inflation pressure and the volume of gas entering the lungs (tidal volume,VT) is the dependent variable that changes as the baby breathes more vigorously or lung mechanics change. The basic functionality of PCV devices is that of a T-piece resuscitator, providing a fixed inflation pressure with every breath regardless of the tidal volme delivered to the lungs. In volume-controlled ventilation (VCV), gas delivery into the ventilator circuit is the primary control variable and pressure becomes the dependent variable, changing as necessary to compensate for the baby breathing and to overcome resistive and elastic forces of the lungs. An innovative third option is volume-targeted ventilation that combines advantages of both modalities by automatically adjusting inflation pressure to maintain a target tidal volume, as will be described in detail later in this paper.

Technological limitations of mechanical ventilation devices available in the early days of neonatal intensive care made it difficult to precisely regulate tidal volume delivery to the tiny lungs of newborn infants. Regulating inflation pressue was much easier and consequently pressure-controlled, time-cycled ventilation became the standard of care in the neonatal intensive care unit (NICU). In addition, the use of uncuffed endotracheal tubes with variable amounts of gas leakage around them meant that accurate tidal volume measurement was unavailable and clinicians had to rely on auscultation and visual assessment of chest rise to judge adequacy of ventilation. Despite these limitations, neonatologists became accustomed to this approach and many continue to employ pressure-controlled ventilation despite compelling evidence that volume-targeted ventilation reduces adverse consequences of mechanical ventilation.1 The ability to control the inflation pressure and time, and tolerance of large leaks around uncuffed endotracheal tubes continue to be seen by some as the major advantages of PCV. The belief that inflation pressure is the main factor in lung injury (we refer to this as ‘barophobia’) has persisted to this day, despite clear evidence that pressure by itself does not injure the lung unless it results in excessively large tidal volume.2