Objective To observe the protective effect of transcutaneous electrical acupoint stimulation(TEAS)on cerebral tissue in elderly hip replacement operation patients during general anesthesia under controlled hypotension.MethodsForty hip replacement operation patients were randomly divided into general anesthesia(GA)control group and TEAS+GA group(n=20in each group).Patients of the two groups during operation were treated with controlled hypotension for reducing blood loss.TEAS(2Hz/100Hz

8-12mA)was applied to bilateral Yuyao(EX-HN 4)and Fengchi(GB 20)and began 30min before GA.General anesthesia was performed by intravenous injection of Midazolam

Diprivan

Fentanyl and Cis-atracurium

sevoflurane-inhaling

Remifentanil

etc.

and the patient's mean arterial pressure was maintained to be about 70% of the normal level(controlled hypotension)by using venous administration of Remifentanil about 10min after the operation.GEM Premier 3000blood gas analyzer was used to analyze levels of the arterial oxygen(CaO2)

internal jugular venous oxygen(CjvO2)

arterio-venous oxygen content difference(Da-jvO2)and cerebral oxygen(CERO2)uptake rates of blood samples before controlled hypotension(T0)

20min after controlled hypotension(T1)

40min after controlled hypotension(T2)and 20min after the end of controlled hypotension(T3).Results Self-comparison of each group showed that in comparison with pre-controlled hypotension

CjvO2levels at the time-points of T1

T2and T3 were significantly increased in both GA control and TEAS+GA groups(P<0.05)

while Da-jvO2and CERO2 uptake rate levels at the time-points of T1

T2 and T3in these two groups were significantly decreased(P<0.05).Comparison between two groups showed that CjvO2levels at the time-points of T2and T3were significantly higher in the TEAS+GA group than in the GA control group(P<0.05)

while Da-jvO2and CERO2uptake rate levels at the time-point of T2were obviously lower in the TEAS+GA group than in the GA control group(P<0.05)

suggesting a reduction of cerebral oxygen consumption after TEAS.No significant differences were found between these two groups in blood CjvO2

Da-jvO2and CERO2uptake rate levels at the time-points of T0and T1(P>0.05).Conclusion TEAS can reduce cerebral oxygen uptake rate in elderly patients undergoing hip replacement during controlled hypotension

suggesting aprotective effect of TEAS on patient's cerebral tissue.