Physiological Effects of Lung Recruitment During General Anesthesia and Low-tidal Volume Ventilation

Physiological Effects of Positive End-expiratory Pressure With or Without Recruiting Maneuvers in Patients Receiving Low-tidal Volume Ventilation During General Anesthesia for Open Abdominal Surgery. A Randomized, Cross-over Study

Low-tidal volume ventilation is arising as a tool to optimize the ventilatory management and to improve clinical outcome in patients undergoing general anesthesia for abdominal surgery.

A recent large randomized controlled trial failed to detect a significant difference between two different approaches for ensuring adequate lung recruitment (PEEP=12 cmH2O + scheduled recruiting maneuvers vs. PEEP 2 cmH2O) during protective ventilation. Thus, in patients undergoing open abdominal surgery and receiving low-tidal volumes, the effects of different positive end-expiratory pressure (PEEP) levels and recruiting maneuvers remain to be established.

Design: prospective, cross-over, physiological trial.

PURPOSE To assess the physiological effects of different PEEP levels with or without scheduled recruiting maneuvers in patients undergoing general anesthesia for open abdominal surgery and receiving low-tidal volume ventilation.

Inclusion Criteria:

• ASA physical status I-II patients
• scheduled for open abdominal surgery (major gastrointestinal surgery: duodeno-cephalo-pancreatectomy, gastrectomy, hemi-colectomy; gynecological surgery; oncologic surgery)
• Expected duration of surgery >= 150 minutes

Exclusion Criteria:

• Pregnancy
• BMI>30 kg/m^2
• hepatic surgery
• Cardiac failure NYHA>2
• History of chronic respiratory failure