Noninvasive ventilation for acute respiratory failure: state of the art (I part)

Background: In the last years Non-Invasive Ventilation (NIV) has been playing an important role in the treatment of Acute Respiratory Failure (ARF). A lot of trials have shown improvements in clinical features (respiratory rate, neurological score), pH and arterial blood gases.
Methods: In particular clinical conditions, such as Acute Cardiogenic Pulmonary Edema (ACPE) and acute exacerbation of Chronic Obstructive Pulmonary Disease (COPD), systematic reviews and meta-analysis show a reduction in the need for intubation and in-hospital mortality compared to standard medical treatment. In other clinical conditions, such as acute asthma, Acute Lung Injury (ALI)/Acute Respiratory Distress Syndrome (ARDS) and severe pneumonia, NIV does not show significant improvements in term of avoided intubations or mortality rate. Although the first important data on NIV comes from studies performed in Intensive Care Units (ICUs), subsequently these methodologies of ventilation have been used with increasing frequency in Emergency Departments (ED) and medical wards.
Results: Studies developed in ICU sometimes report slightly worse outcomes compared to studies performed in general wards due to the need to treat more severe patients in ICU. Aetiology remains one of the most important factor determining prognosis: different pathological mechanisms substain different clinical conditions and not in all cases the application of positive pressures to the airways is useful. NIV for ARF due to COPD and ACPE is feasible, safe and effective also in a general medical ward if selection of patients, staff training and monitoring are appropriate: its early application improves clinical parameters, arterial blood gases, prevents endotracheal intubation, decreases mortality and hospitalisation. This should encourage the diffusion of NIV in this specific setting.