Deep Breathing With and Without Pressure Support and PEEP for Preoxygenation in Obese Patients

Effects of Pressure Support and Positive End-Expiratory Pressure Added to Deep Breathing Preoxygenation on Gastric Distension in Obese Patients: A Randomized Controlled Trial

Obese patients are at increased risk of low oxygen levels during the induction of general anesthesia. Preoxygenation with a face mask before anesthesia is routinely used to increase oxygen reserves. This study compares three preoxygenation techniques: deep breathing alone, deep breathing with pressure-supported ventilation, and deep breathing with pressure-supported ventilation plus positive end-expiratory pressure (PEEP).

The main goal of the study is to determine how quickly each technique allows patients to reach an adequate level of oxygen in the lungs. In addition, the study evaluates whether these techniques cause gastric distension, which could increase the risk of regurgitation. Gastric ultrasound is used to assess stomach size before and after preoxygenation.

The results of this study will help identify the most effective and safest method of preoxygenation in obese patients undergoing elective surgery.

Inclusion Criteria:

• Age ≥ 18 years
• Obesity
• Scheduled for elective surgery under general anesthesia
• Able to cooperate with deep breathing during preoxygenation

Exclusion Criteria:

• Hemodynamic instability
• Poor cooperation
• Preoperative oxygen therapy requirement
• Conditions in which positive pressure ventilation may be harmful (e.g., increased intracranial or intraocular pressure)
• Pregnancy
• Emergency surgery
• Beard (preventing adequate face mask seal)
• Previous gastric surgery
• Inability to visualize the gastric antrum by ultrasonography