Patients admitted to Intensive Care Unit often are affected by acute respiratory failure at admission or during hospital stay, with a mortality of 30%.

Treatment remains largely supportive with mechanical ventilation as the mainstay of management by improving the hypoxemia and reducing the work of breathing; however, the mechanical forces generated during ventilation can further enhance pulmonary inflammation and edema, a process that has been termed ventilator induced lung injury (VILI). Consequently, in clinical practice the lung protective ventilation is mainly based on the reduction of the tidal volume, the airway and the transpulmonary plateau pressure. A good clinical practice is based on the assessment of changes in respiratory mechanics.

Aim of the study is to determine the accuracy of the OPTIVENT system in measuring transpulmonary pressure, comparing it with the systems currently in use in our Operative Unit.

Inclusion Criteria:

• acute respiratory failure
• invasive mechanical ventilation.

Exclusion Criteria:

• haemodynamic instability
• presence of barotrauma
• esophageal disease.

Adult patients admitted to our Intensive Care Unit affected by acute respiratory failure, mechanically ventilated.