Dinamic intrinsic PEEP is

Dynamic intrinsic positive end-expiratory pressure (PEEPi dyn) play an important pathophysiology role in many acute respiratory pathologies.

The most accurate method to quantify PEEPi dyn is to measure the rise in transdiaphragmatic pressure (Pdi) at end expiration at the point of the contraction of the inspiratory muscles until inspiratory flow starts.

Such method, however, is invasive, poor comfortable and require patient active collaboration.

The purpose of this study is describe a new non-invasive method for estimate PEEPi dyn and validate this method with gold-standard-one.

Inclusion Criteria:

• Acute or chronic respiratory failure
• Age >=18 y

Exclusion Criteria:

• Lack of informed consent
• Controindication to the placement of oesophageal and gastric catheter:

esophageal varices, gastric or oesophageal bleeding in the previous 30 days, gastric or oesophageal surgery in the preceding year.

• Cardiac arrest
• Severe emodinamic instability (> 1 vasoacttive drug)
• Acute coronary syndrome (AMI/UA)
• Inability to protect airway
• Respiratory arrest
• Pregnancy suspected or confirmed
• Diaphragm palsy
• Curarization in the preceding five hours
• Mechanical ventilation in controlled mode.

Patients with both acute or chronic respiratory insufficiency, who required respiratory mechanics measurements for clinical purpose.