During minimally invasive surgery, a pneumoperitoneum is created to facilitate surgical visualization. Although effective in facilitating the procedure, there are respiratory consequences of the pneumoperitoneum, which significantly increases intra-abdominal pressure (IAP) up to 20 cmH2O. The increased IAP can decrease functional residual capacity and increase closing capacity resulting in increased resistance, decreased compliance, and increased ventilation-perfusion mismatch. In a randomized, cross-over design, this study will evaluate in sequential order, 3 modes of ventilation during laparoscopic bariatric surgery to determine which is better able to support oxygenation and ventilation while limiting the peak inflating pressure (PIP).

Inclusion Criteria:

• Laparoscopic bariatric surgery requiring intra-arterial blood pressure monitoring, age 14-20 years.

Exclusion Criteria:

• None

Bariatric surgery patients