Monitoring Lung Recruitment Maneuver in Anesthetized Morbidly Obese

Morbid obese patients present changes in respiratory physiology caused by weight overload. Intraoperative atelectasis is a pulmonary complication that affects not only gas exchange but also respiratory mechanics. The present study was aimed to test the role of different parameters for monitoring the treatment of atelectasis by a lung recruitment maneuver.

This is a prospective study perform in 30 anesthetized morbidly obese undergoing bariatric surgery. Lung mechanics and volumetric capnography will be non-invasively assessed during laparoscopy. Esophageal pressure will be measured by an esophageal balloon to measure transpulmonary pressure. A lung recruitment maneuver will be done. The optimum level of positive end-expiratory pressure (PEEP) is defined as the PEEP level when transpulmonary pressure remains positive during the PEEP titration trial of the recruitment maneuver. Lung collapse is detected when transpulmonary pressure becomes negative. The behavior of the studied volumetric capnography and lung mechanics parameters will be compared with the reference transpulmonary pressure signal.

Morbidly obese patients undergoing bariatric surgery (single-arm study) will receive a Lung recruitment maneuver to treat atelectasis..

A Lung recruitment maneuver is aimed to resolve atelectasis during mechanical ventilation. It consists in a brief and controlled increment in airways pressure using pressure control ventilation. Positive end-expiratory pressure (PEEP) is increases every 5 centimeters of water (cmH2O), from 0 to 20 cmH2O keeping a fixed driving pressure of 20 cmH2O. A final step of 40 cmH2O of plateau pressure was maintained for 10 breaths, returning then to standard ventilatory settings.

Inclusion Criteria: Body mass index (BMI) > 40 kg/m2 Written inform consent Scheduled for bariatric surgery American Society of Anesthesia physical status II-III Exclusion Criteria: Acute pulmonary disease Emergency surgery