To evaluate the sensitivity, specificity and diagnostic accuracy of bedside transthoracic ultrasound examination in the diagnosis and follow up of ventilator associated pneumonia.

VAP is the most frequent hospital-acquired infection in intensive care units. Depending on the diagnostic criteria used, its incidence ranges from 5% to 67%. The risk of acquiring VAP is 3% per day during the first 5 days on mechanical ventilation, and it is decreased to 1% per day for the following days.

VAP is suspected when subject shows high grade fever, increase in leukocyte count, change in color of sputum and tachypnea. It's a leading cause of mortality in 15- 65% of the cases.

Serial chest x-ray for diagnosis and follow up, done at time of diagnosis, after 5 days and after 10 days. Chest radiography is consistently carried out after LUS , LUS is done every other day, measuring the largest area of consolidation according to the intercostal space and direction of the probe . Chest radiography is read by two physicians.

Inclusion Criteria:

• Mechanical ventilation for at least 48 hours.
• New or evolving infiltrate on chest radiograph (CXR).
• Clinical pulmonary infection score more than or equal 6

Exclusion Criteria:

• Patients who are less than 18 years old.
• Patients who have evidence of pneumonia before or prior to being mechanically ventilated.
• Patients with pulmonary infarction.