0° of Trendelenburg Tilting Position 10° of Trendelenburg Tilting Position Degree of HR 0° 30° 60° 0° 30° 60° Group I 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 1 (2.9%) Group II 1 (2.9%) 1 (2.9%) 2 (5.9%) 3 (8.8%) 5 (14.7%) 6 (17.6%) Group III 0 (0%) 7 (20.6%) 7 (20.6%) 3 (8.8%) 2 (5.9%) 6 (17.6%)

Table 2: Number (percentages) of common carotid artery to sit directly underneath the internal jugular vein Values are numbers (percentages). Group I, BMI< 25 kg/m2; Group II, 25 kg/m2 ≤BMI< 30 kg/m2; Group III, BMI ≥ 30 kg/m2; BMI, body mass index; HR, head rotation.