Diaphragmatic Ultrasound in Acute Hypoxic - Hypercapnic Respiratory Failure (ARF)

Mortality of acute hypoxic - hypercapnic respiratory failure (ARF) patients underwent invasive mechanical ventilation is demonstrated to be higher than in patients who underwent only non invasive mechanical ventilation (NIV). There is an increased need to detect more predictive factors for NIV failure, in order to better identify patients most at risk of facing negative outcomes. The aim of this experimental pilot study is to evaluate the feasibility of the ultrasound of diaphragm in ARF patients underwent non invasive mechanical ventilation ( primary endpoint ). Furthermore the secondary aim is to observe any relationship between diaphragmatic function (excursion), diaphragmatic thickening and the timing of arterial blood gases (ABGs) compensation in patients with ARF undergoing NIV treatment; additional outcomes are: correlation with dyspnea level, time of mechanical ventilation, NIV failure, rate of tracheostomy, length of stay in ICU and in-hospital and 90-day mortality.