Acute dyspnea is a common disease in emergency medicine. Mortality remains high is estimated at 15%. One third of initial diagnoses before paraclinical examination are estimated to be inaccurate. Lung ultrasound is a quick and immediate examination. Also, it is provided and performed at the bedside. The " Blue protocol " was designed by Daniel A. Lichtenstein as a diagnostic aid in dyspneic patients. It allows to obtain a diagnostic in more than 90% of acute dyspnea. However there is no validation in emergency medicine.

The main purpose is to evaluate the interest of the " Blue protocol "in the management and orientation of the dyspneic patient

Inclusion Criteria:

• age over 18 years
• dyspneic patient requiring management by an emergency physician
• information given and no patient opposition.

Exclusion Criteria:

• patient under a legal protection measure
• lack of social security

Each dyspneic patient meeting the inclusion criteria and admitted in emergency room will be included in the protocol.