Effect of pneumoperitoneum on hemodynamics and inspiratory pressures during natural orifice transluminal endoscopic surgery (NOTES): An experimental, controlled study in an acute porcine model - Delius, S von; Huber, W; Feussner, H; Wilhelm, D; Karagianni, A; Henke, J; Preissel, A; Schneider, A; Schmid, R M; Meining, A (Endoscopy, 2007)