Left ventricular failure (LVF) is a common cause of acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

This association is frequently underestimated with regard to the difficulty of clinical diagnosis .

The investigators expect that the application of pressure support under NIV could be useful in this issue.

Acute heart failure (AHF) is a common cause of COPD exacerbation however its role is very often underestimated. Until now, the use of echocardiography and some invasive hemodynamic exploration techniques such as the Swan-ganz catheter has been stated as reference. Other noninvasive diagnostic methods have been studied, such as systolic time intervals and Valsalva maneuver, but their application still difficult in patients with COPD exacerbation, especially in emergency department (ED) settings. the study aimed to evaluate the performance of a new diagnostic technique based on the measurement of the PAR using non invasive ventilation (NIV) for the early identification of left ventricular failure (LVF) in patients presenting to the ED with acute COPD exacerbation

Inclusion Criteria:

• patients with a history of COPD
• consulted the emergency department for AECOPD defined by a respiratory rate >25c/min, SaO2 <90%, pH <7.35 and PaCO2 >6kPa were included.

Exclusion Criteria:

• hemodynamic instability requiring the use of vasoactive drugs
• patients with contraindications to NIV (Glasgow score <12, swallowing disorder or severe bronchial obstruction, vomiting, and those with upper airway obstruction or ongoing upper gastrointestinal bleeding and altered bronchial clearance)
• non cooperative patients
• who refused to give consent.

all patients presenting to the ED with an acute COPD exacerbation