To evaluate the development of cerebral anoxia during controlled hypotension with nicardipine or urapidil after carotid endarterectomy in patients.

Forty-four patients of either sex, aged 48-64 yr, scheduled for elective carotid endarterectomy under general anesthesia, requiring controlled hypotension after operation, were divided into nicardipine group (group N) and urapidil group (group U) using a random number table method, with 22 patients in each group. Nicardipine at 2.5 μg·kg^-1·min^-1 was intravenously infused in group N, and urapidil 2 μg·kg^-1·min^-1 was intravenously infused in group U. After systolic blood pressure was decreased to 130-140 mmHg, the consumption of nicardipine was adjusted to 0.2-0.5 μg·kg^-1·min^-1 and the consumption of urapidil to 1-2 μg·kg^-1·min^-1 in group N and group U, respectively, to maintain systolic pressure at 130-140 mmHg. Heart rate (HR), cardiac index (CI), bispectral index (BIS) value, regional cerebral oxygen saturation (rSO₂) and end-tidal pressure of carbon dioxide (P_ETCO₂) were recorded after entering the operating room (baseline), at the beginning of controlled hypotension (T₁), and at 5, 10, 20, 30, 60 and 120 min after systolic blood pressure was decreased to the target hypotension (T_2-7). Development of cerebral anoxia (the relative decrease in rSO₂ >12% of the baseline value) was recorded in controlled hypotension period.

Compared with the value at T₁, the HR at T_{2, 3} and CI at T_3-7 were significantly increased (P<0.05), and no significant change was found in rSO₂, P_ETCO₂ or BIS value at the other time points in group N (P>0.05), and rSO₂ was significantly decreased at T_3-7 (P<0.05), and no significant change was found in HR, CI, P_ETCO₂ or BIS value at the other time points in group U (P>0.05). Compared with group N, the HR at T_{2, 3}, CI at T_3-7 and rSO₂ at T_3-7 were significantly decreased in group U (P<0.05). The incidence of cerebral anoxia was significantly higher in group U than in group N (P<0.05).

Controlled hypotension with nicardipine is recommended after carotid endarterectomy in order to avoid the development of cerebral anoxia in the patients.

Nicardipine; Hypotension, controlled; Endarterectomy, carotid; Urapidil