经皮穴位电刺激复合药物全麻行控制性降压对心脏的保护效应

Cardiac protective effects of transcutaneous electrical acupoint stimulation combined with general anesthesia for controlled hypotension

目的：通过经皮穴位电刺激（TEAS）复合药物在全麻下行控制性降压的方法，探讨其对心脏的保护效应及作用机制。方法：16只雄性比格犬随机分为单纯药物全麻行控制性降压组（对照组）和经皮穴位电刺激复合药物全麻行控制性降压组（观察组）。两组动物均以异氟醚联合硝普钠行控制性降压，将动脉血压降至30％基础平均动脉血压（MAP）水平并维持60min。观察组选用双侧“合谷”“足三里”“三阴交”“曲池”穴，刺激强度3～5mA，频率2Hz／100Hz，电刺激在观察组动物生理状态稳定后开始至维持目标MAP60min后停止；而对照组此时不做TEAS干预。采用生物信号采集系统监测股动脉MAP、左心室内压、Ⅱ导联心电图T波、ST段的变化；TUNEL法检测心肌细胞凋亡阳性表达。结果：两组动物均能维持稳定的目标血压水平。在血压回升1h时，观察组MAP恢复到控压前水平，而对照组MAP（84．91±6．36）mmHg仍低于控压前水平（111．02±4．15）mmHg（P〈0．05），也明显低于观察组MAP值（109．56±6．14）mmHg（P〈0．05）。对照组动物左心室内压下降最大速度（-dp／dtmax）血压回升1h后（3156．32±332．82）mmHg／s仍明显小于降压前（4585．33±638．55）mmHg／s（P〈0．05），而观察组差异无统计学意义。在维持目标低血压60min时，对照组动物ST段明显压低（P〈0．05），而观察组动物ST段虽有压低，但差异无统计学意义。术后72h时，观察组动物心肌细胞凋亡阳性表达数（24．67±2．45）个／mm^2明显少于对照组动物（37．89±1．90）个／mm^2（P〈0．01）。结论：TEAS复合药物全麻行控制性降压能明显缩短血压回升时间，改善心肌缺血情况和心功能恢复能力，减少心肌细胞凋亡，从而起到心肌保护作用。

Objective To explore the protective effect and the mechanism of controlled hypotension induced by transcutaneous electrical acupoint stimulation （TEAS） combined with general anesthesia. Methods Sixteen male Beagles were randomly divided into a group of controlled hypotension induced by simple general anesthesia （control group） and a group of controlled hypotension induced by TEAS combined with general anesthesia （observation group）. All the animals were administered with combination of Isoflurane and Sodium Nitroprusside （SNP） for controlled hypotension without TEAS until the arterial pressure was lowered to 30% basic mean arterial pressure （MAP） for 60 min. In the observation group, TEAS （2 Hz/100 Hz, 3-5 mA） was applied to ＂Hegu＂ （LI 4）, ＂Zusanli＂ （ST 36）, ＂Sanyinjiao＂ （SP 6） and ＂Quehi＂ （LI 11） from the beginning of physiological conditions stability to the end of maintained low MAP for 60 rain, but there was no TEAS in control group. The changes of MAP, the left intraventrieular pressure （LIVP）, T wave and ST-T segment of II lead electrocardiogram （ECG） were monitored with the physiological signal acquisition system, and myocardial apoptosis was detected by TUNEL method. Results All the animals could maintain stable required low blood pressure. At one hour after cease of controlled hypotension, MAP of （109.56 ± 6.14） mmHg returned to the basic level in the observation group, while MAP of （84.91±6.36） mmHg was still lower than its basic MAP of （111.02±4.15） mmHg in the control group （P〈0.05）, showing significant difference in MAP between the two groups （P〈0.05）. dp/dtmax of （3156.32±332.82） mmHg/s showed significant lower than its basic value of （4585.33±638.55） mmHg/s when blood pressure increased for 1h in the control group （P〈0.05）, but there was no difference in the observation group. When the objective low MAP maintaining for 60 min the ST segment was decreased significantly in the con trol group （P〈0.05）, but there was no difference in the observation group. The numbers of positive apoptosis cardiocytes in the observation group were （24.67±2. 45） cells/mm^2 , which were significantly fewer.than （37.89±1.90） cells/mm^2 in the control group （P〈0.05）. Conclusions TEAS combined with general anesthesia for controlled hypotension can significantly shorten restoration time of MAP, help to improve myocardial ischemia and the cardiac functional recovery and reduce myocardial apoptosis so as to produce myocardial protection.