Non-invasive ventilatory support and patient self-induced lung injury: Pathophysiology

Abstract

Respiratory support is an essential component in patients with respiratory failure in whom hypoxemia and/or hypercapnia cannot be controlled with medical treatment. The positive pressure ventilation (PPV) indicated in such a clinical scenario can be applied invasively or noninvasively. The application of non-invasive ventilation (NIV) mitigates the risk of developing complications, especially from intubation. It also reduces the mortality risk associated with invasive mechanical ventilation (IMV). The oxygenation improvement coupled with lung and diaphragm protection produced by NIV may help to prevent complications. However, in recent years, the phenomenon of patient self-induced lung injury (P-SILI), i.e., the possibility of lung injury induced or worsened by the patient's own inspiratory effort, has emerged. In patients with lung injury leading to an increased inspiratory effort, spontaneous breathing entails the risk of generating high transpulmonary pressure fluctuations and local lung overstrain. Although no studies have yet demonstrated that a ventilation strategy to limit the risk of P-SILI can improve outcome, the concept of P-SILI is based on sound physiological judgment, the accumulation of clinical observations, and consistent experimental data. Further research, needed to determine the best non-invasive strategy during de novo hypoxemic respiratory failure.In this chapter, we discuss the ways to identify the conditions at risk for ventilation-dependent lung injury during NIV in a clinical setting and the extent to which this can help personalize treatment strategies.