Fig. 6

Ratio of S_U/S_R and PSV_U/PSV_R. a Compared with T0, the ratio of S_U/S_R increased significantly at T1 and T2 on the side ipsilateral to the cannulation (p < 0.001 and p = 0.002, respectively). Compared with T1, the ratio of S_U/S_R decreased significantly at T3 (p = 0.01). No difference in the ratio of S_U/S_R was found among the four time points on the side contralateral to the cannulation. S_U: cross-sectional area of ulnarartery; S_R: cross-sectional area of radialartery. b Compared with T0, the ratio of PSV_U/PSV_R increased significantly at T1 and T2 on the side ipsilateral to the cannulation (both p < 0.001); compared with T1, the ratio of PSV_U/PSV_R decreased significantly at T2 and T3 (both p < 0.001); compared with T2, the ratio of PSV_U/PSV_R decreased significantly at T3 (p < 0.001). No difference in the ratio of PSV_U/PSV_R was observed among the four time points in the side contralateral to the cannulation