Diaphragmatic dysfunction (DD) is one of the main risk factors for post operative respiratory distress syndrome. Ultrasonography is a diagnosis tool for DD but few studies have been published. The aim of this prospective study is to compare the achievement of diaphragmatic function depending on the type of surgery (abdominal and head and neck surgery).

Inclusion Criteria:

• Age>18 years
• Upper abdominal or head and neck surgery
• written consent

Exclusion Criteria:

• Age <18 years
• Pregnancy
• History of neuropathy or myopathy,
• History of diaphragm paralysis, thoracic surgery, pneumothorax, pneumomediastinum