Objective To observe the effects of transcutaneous electrical acupoint stimulation(TEAS) at different times on the stress response during anesthesia and operation in the patients undergoing open posterior lumbar surgery. Methods A total of 94 patients undergoing open posterior lumbar surgery were randomly assigned to preoperative TEAS group(32 cases)

intraoperative TEAS group(31 cases) and sham-TEAS group(31 cases). The same anesthetic method was used in the patients of 3 groups. Four electrodes were attached to the bilateral Hegu(LI4) and Neiguan(PC6) and connected to the electronic acupuncture instrument when patients entered the operation room. In the preoperative TEAS group

the patients received TEAS(10 to 20 mA) for 30 min before the anesthetic induction. TEAS(15 mA) was provided immediately when the operation starts till the end of ope-ration for the patients of the intraoperative TEAS group. In the sham-TEAS group

the electronic acupuncture instrument was switched on during the whole procedure of operation

but no electric current was output. Separately

at the moment of entering the operation room(T_0)

before endotracheal intubation(T_1)

at the time of endotracheal intubation(T_2)

10 min after skin resection(T_3)

at the end of surgery(T_4)

recovery from anesthesia(T_5) and at the time of extubation(T_6)

the heart rate(HR) and mean arterial pressure(MAP) were recorded. Using ELISA

the concentrations of epinephrine(E)

norepinephrine(NE)

dopamine(DA)

cortisol(Cor) in serum were assayed at T_0

T_3

and T_4; and blood glucose was tested with blood sugar paper at the same time points. Results Compared with T_0 of the same group

HR was increased at T_2 and decreased at T_3 of the patients in the sham-TEAS group and the intraoperative TEAS group(P<0.05). Compared with the sham-TEAS group at the same time points

HR was decreased at T_2 and increased at T_3 of the patients in the preoperative TEAS group(P<0.05)

and it was decreased at T_6 of patients in the intraoperation TEAS group(P<0.05). HR was reduced at T_2 in the preoperative TEAS group when compared with the intraoperative TEAS group. Compared with T_0 of the same group

MAP was elevated at T_2 and reduced at T_3 and T_4 in the sham-TEAS group(P<0.05); it decreased at T_3

T_4 and T_5 in the preoperative TEAS group(P<0.05); it rose at T_2 and was reduced at T_3

T_4 and T_5 in the intraoperative TEAS group(P<0.05). When compared with the sham-TEAS group at the same time points

MAP decreased at T_2 in the preoperative TEAS group(P<0.05)

and at T_6 in the intraoperative TEAS group(P<0.05). MAP was reduced at T_2 and elevated at T_6 in the preoperative TEAS group in comparison with the intraoperative TEAS group(P<0.05) at the same time points. Compared with T_0 of the same group

the contents of E was increased at T_3 in the sham-TEAS group and the intraoperative TEAS group(P<0.05); it was increased in all of the three groups at T_4(P<0.05); the contents of NE

DA

Cor and the blood glucose were increased at T_4 in the sham-TEAS group(P<0.05). Compared with the sham-TEAS group at the same time points

the contents of E

DA at T_3 and T_4 and Cor at T_3 in serum of the preoperative TEAS group were decreased(P<0.05); and the contents of E

NE

DA and Cor at T_4 in the intraoperative TEAS group were decreased(P<0.05). Conclusion TEAS-assisted general anesthesia can better maintain the stability of HR and MAP during anesthesia and operation in patients undergoing open posterior lumbar surgery

and reduce surgical stress response.