Optimal Strategies of Mechanical Ventilation: Can We Avoid or Reduce Lung Injury?

Abstract

Background: Despite the increasing use of non-invasive support modalities, many preterm infants still need invasive mechanical ventilation. Mechanical ventilation can lead to so-called ventilator-induced lung injury, which is considered an important risk factor in the development of bronchopulmonary dysplasia. Understanding the concepts of lung protective ventilation strategies is imperative to reduce the risk of BPD.

Summary: Overdistension, atelectasis, and oxygen toxicity are the most important risk factors for VILI. A lung protective ventilation strategy should therefore optimize lung volume (resolve atelectasis), limit tidal volumes, and reduce oxygen exposure. Executing such a lung protective ventilation strategy requires basic knowledge on neonatal lung physiology. Studies have shown that volume-targeted ventilation (VTV) stabilizes tidal volume delivery, reduces VILI, and reduces BPD in preterm infants with respiratory distress syndrome. High-frequency ventilation (HFV) also reduces BPD although the effect is modest and inconsistent. It is unclear if these benefits also apply to infants with more heterogeneous lung disease.

Key messages: Understanding basic physiology and the concept of ventilator-induced lung injury is essential in neonatal mechanical ventilation. Current evidence suggests that the principles of lung protective ventilation are best captured by VTV and HFV.

Keywords: Bronchopulmonary dysplasia; High-frequency ventilation; Lung protective ventilation; Preterm infants; Volume guarantee; Volume-targeted ventilation.

Fig. 1.

Basic principles of HFV. A continuous distending pressure (CDP) is applied to the lungs and on top of this pressure swings are delivered with a preset delta pressure. Each oscillation has an inspiration time (Ti) and expiration time (Te) and the sum of these is the cycle time. As indicated in the figure, at a frequency of 10 Hz (600/min) the cycle time will be 0.1 s.