The aim of the study is to evaluate in patients with severe acute respiratory failure requiring non invasive mechanical ventilation BNP levels at admission and during the following 24 hours during non invasive mechanical ventilation (Non Invasive Positive Pressure Ventilation or Continuous positive airway pressure).~Because in patients affected by acute respiratory failure it is often difficult to distinguish if the disease precipitating the respiratory failure is a cardiac disease or a lung disease, aim of the present study is to evaluate the discriminating role that BNP could have in this group of patients; evaluation will be completed, once obtained clinical stabilisation, with an echocardiography and respiratory functional test.
The purpose of the study is to evaluate variation of BNP in non invasive mechanical ventilated patients with severe acute respiratory failure.