Carotid sinus nerve blockade (CSNB) has been shown to be effective for management of post-carotid endarterectomy (CEA) hypotension. The underlying hemodynamic changes are unknown. We retrospectively analyzed a recorded arterial blood pressure (ABP) waveform using a Modelflow technique. After declamping, total peripheral resistance (TPR) decreased (-65% of predeclamping value), but cardiac output (CO) and stroke volume (SV) increased (+60 and +57% of predeclamping value, respectively). CSNB abruptly increased blood pressure (BP) and TPR (75 and 95% of nadir, respectively), while CO and SV gradually decreased to -21 and -16% of maximum value, respectively). In conclusion, we found that severe decline of TPR was a cause of severe hypotension after declamping and CSNB increased BP mainly through increase in TPR, with little change in CO and SV.