Atelectasis and poorly ventilated lung areas are negative consequences of general anesthesia observed in adult as well as in children. The reported incidence of this anesthesia-induced atelectasis is high and comes from 83 % to almost 100 %. The diagnosis of this entity is difficult to do at the bedside; they are commonly small and mostly invisible to standard chest X-ray images. Several methods have been suggested to reduce the impact of atelectasis during surgery. However, few intraoperative modalities for the diagnosis and monitoring of atelectasis are available. Lung ultrasound imaging is a promising non-invasive, non-radiant, portable and easy to use tool that as yet to be studied in the intraoperative setting. 80 adult patients with different ventilation strategies were divided into four groups, 20 patients were included in the 1st group conventional ventilation with large tidal volume 10ml/kg, with FiO2 1 with neither PEEP nor recruitment, 20 patients were included in the 2nd group conventional ventilation with large tidal volume 10ml/kg, with FiO2 0.6 with neither PEEP nor recruitment, 20 patients were included in the 3rd group protective lung ventilation with tidal volume 6ml/kg, with FiO2 1 plus recruitment and PEEP, and 20 patients were included in the 4th group protective lung ventilation with tidal volume 6ml/kg, with FiO2 0.6 plus recruitment and PEEP comparative study between lung ultrasound atelectasis score (LUS), the median and Interquartile range (IQR) of lung ultrasound score was done. There was statistically significant difference between the four groups of the study at all times except for baseline reading (P