The study aims to compare the staircase alveolar recruitment maneuver with PEEP titration versus sustained inflation alveolar recruitment maneuver by using lung ultrasound score as an indicator of improving lung atelectasis in bariatric surgery

Weight loss surgery, often known as bariatric surgery, is an effective obesity treatment. Most people undergoing such surgery may show an improvement in, or the resolution of, conditions such as diabetes, dyslipidemia, hypertension, and obstructive sleep apnea.

Currently, there is no standard ventilation strategy has been established for obese patients. However, there is some evidence that recruitment maneuvers (RM) combined with protective lung ventilation strategy improve oxygenation and compliance compared to other strategies.

Alveolar recruitment maneuver refers to the periodic hyperinflation of the lungs that has been utilized to open up the lung and keep the lung open in anesthetized patients. The use of recruitment maneuvers has been shown to reduce the incidence and extent of atelectasis during general anesthesia by different methods.

Lung ultrasonography is considered a useful tool in perioperative care. Recent research showed that lung ultrasound could assess lung aeration and diagnose anesthesia-induced atelectasis accurately in the perioperative period by measuring the extent of atelectasis by the scoring system; also, the response to recruitment manoeuver for each patient can be evaluated easily. Thus, it has great potential as a bedside non-invasive, sensitive tool for guiding effective recruitment manoeuvers to reduce the formation of pulmonary atelectasis in the surgical setting

Inclusion Criteria:

• Adult morbidly obese patients (Body mass index < 40kg / m2 or Body mass index < 35kg / m2 with obesity-related comorbidities such as hypertension, diabetes, and sleep apnea)
• undergo elective bariatric laparoscopic surgery with an expected duration of at least one hour under general anesthesia.

Exclusion Criteria:

• Patient refusal to participate in the study.
• Patients with a previous history of thoracic surgery.
• Patients with a history of chest disease (COPD, emphysema, or pneumothorax).
• Patients with abnormal pre-operative chest radiographs such as pneumonia, pleural effusion.
• Patients with heart failure or impending failure.
• Patients with known hypovolemia.
• Patients with increased intracranial pressure.

The data will be available upon reasonable request from the principal investigator

For one year after completion of the study