Non-invasive mechanical ventilation to prevent ICU-acquired infection

Several forms of supportive techniques for respiration in intensive care units (ICU) are currently available. The most widely used is invasive mechanical ventilation through the use of an endotracheal tube (ETT). ETTs are proved to be important contributors to the pathogenesis and development of ventilator-acquired pneumonia (VAP) as artificial airways interfere with a number of respiratory tract defence mechanisms and facilitate bacterial colonisation of the tracheobronchial tree. The occurrence of VAP is known to be one of the leading cause of morbidity and mortality in ICUs. On that basis, non-invasive techniques have been developed through the use of patient-ventilator interfaces in the form of facial masks which allow the development of ventilatory modalities working in synchrony with the patient. The purpose of this review is to examine the impact of non-invasive ventilation on the occurrence of ICU-acquired infections, most likely VAP, when used as an alternative for endotracheal intubation or when applied after early extubation. Regarding the reduction of endotracheal intubation, many studies have confirmed the net benefit of using non-invasive ventilation, mostly in chronic obstructive pulmonary diseases with acute hypercapnic ventilatory failure, in cardiogenic pulmonary edema, and in selected populations such as immunocompromised patients. Additionally, some studies have demonstrated a substantial benefit on hospital mortality. Early extubation with immediate application of non-invasive ventilation as a method to wean patients from invasive ventilation has shown a significant effect on hospital mortality. Overall, in our experience, patients with chronic obstructive pulmonary disease with hypercapnic acute respiratory failure are most likely benefiting from non-invasive ventilation either in the acute setting or during the immediate post-extubation phase. Acute cardiogenic patients must also receive primary respiratory non-invasive support. For immunocompromised patients, given the broad range of immunosuppression settings, the underlying condition should guide the decision of applying non-invasive support or not in a case by case approach.