METHODS	1 ) The lightwand was bent at 20 degrees , 40 degrees , 60 degrees , or 80 degrees with 0 cm extruded from the endotracheal tube ; 2 ) the lightwand was exposed from the endotracheal tube with -0.5 , 0 , 1 , 2 , 3 , or 4 cm with 40 degrees angle ; and 3 ) the effect of obesity was tested with 40 degrees angle and 0-cm extrusion .\