[Gastric dynamics analysis of TEAS combined SNP induced general anesthesia when controlled hypotension dropped to 60% of the MAP baseline].

OBJECTIVE: To observe the effect of gastric dynamics by transcutaneous electrical acupoint stimulation (TEAS) combined general anesthesia when controlled hypotension dropped to 60% of the mean arterial prenssure (MAP) baseline, and to provide experimental evidence for organ protection in clinical controlled hypotension. METHODS: Eighteen male beagles were randomly divided into three groups, the general anesthesia group (blank), the general anesthesia induced controlled hypotension group (control), and the general anesthesia combined TEAS induced controlled hypotension group (experiment), 6 in each group. Controlled hypotension was performed in the latter two groups with isoflurane inhalation and intravenous injection of sodium nitroprusside (SNP). The mean arterial pressure (MAP) was lowered to 60% of the MAP baseline and kept for 60 min. Controlled hypotension was not performed in Beagles of the control group. For Beagles in the experiment group, TEAS [2/100 Hz, (4 ± 1) mA] was applied to bilateral Hegu (LI4), Quchi (LI11), Zusanli (ST36), and Sanyinjiao (SP6) from stable physiological conditions to the end of maintaining stages. Changes of EGG frequencies and EGG amplitudes were monitored. Serum levels of gastrin (GAS) and motilin (MTL) were also detected at corresponding time points during and after experiment. RESULTS: As for the pressure control effect of TEAS combined general anesthesia in the controlled hypotension, during the process of controlled hypotension (T1-T4), MAP levels of two controlled pressure groups remained relatively stable, and were kept at 60% of the MAP baseline. When the blood pressure dropped to the target low MAP and maintained at 60 min (T1-T4), EGG amplitudes of Beagles in all the three groups showed decreasing tendency. But it was more obviously lower than its basic level in the control group (P <0.05), while it was not obviously decreased in the experiment group (P < 0.05). EGG frequencies of Beagles in all the three groups showed no obvious change during this stage. By the end of the MAP rising stage (T8), the EGG amplitude of the experimental group was significantly higher than that of the control group and the blank group (P < 0.05), while it didn' t show any obvious increase in the control group. During this period, EGG frequencies of the two controlled hypotension groups decreased more than those of the blank group. Two h after rising blood pressure (at T9), EGG amplitudes and frequencies in the two controlled hypotension groups basically restored to their respective baselines and levels of the blank group at T9. At 2 h (T9) after controlled hypotension, serum levels of GAS and MTL were lower than those of basic levels in the two controlled hypotension groups (P <0.05). However, serum levels of GAS and MTL had an increasing trend in the two controlled hypotension groups at 24-72 h (T10-T12). Besides, the increasing speed and amplitude was better in experiment group than in the control group at T10-T12. However, there was no statistical difference between the two groups (P > 0.05). At 72 h (T12) serum levels of GAS and MTL had basically restored to their basic levels in the two controlled hypotension groups and that of the blank control group. CONCLUSION: EGG amplitudes could be effectively improved in TEAS combined general anesthesia for controlled hypotension at 60% of the MAP baseline, the recovery of the serum GAS level accelerated, gastric power improved and stomach protected.

Transcutaneous electrical nerve stimulation regulates organ blood flow and apoptosis during controlled hypotension in dogs.

Transcutaneous electrical nerve stimulation (TENS) is commonly used in clinical practice for alleviating pains and physiological disorders. It has been reported that TENS could counteract the ischemic injury happened in some vital organs. To determine the protective effect of TENS on internal organs during CH in dogs, target hypotension was maintained for 60 min at 50% of the baseline mean arterial pressure (MAP). The perfusion to the brain, liver, stomach, and kidney was recorded and apoptosis within these organs was observed. Results showed that when arriving at the target MAP, and during the maintaining stage for 10 min, perfusion to the stomach and liver in the CH+TENS group was much higher than in the CH group (P<0.05). Perfusion to the cerebral cortex greatly declined in both the controlled pressure groups when compared with the general anesthesia (GA) group (P<0.05). After withdrawing CH, the hepatic blood flow in both the CH and CH+TENS groups, and the gastric and cerebral cortical blood flow in the CH+TENS group, were rapidly increased. By the end of MAP restoration, gastric blood flow in the CH group was still low. At 72 h after applying CH, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells in stomach and kidney tissue from the CH group were significantly increased compared with those in the GA group (P<0.05). There was no significant difference in TUNEL-positive cells in the liver and hippocampus among the three groups. Our results demonstrated that CH with a 50% MAP level could cause lower perfusion to the liver, stomach, cerebral cortex, and kidney, with apoptosis subsequently occurring in the stomach and kidney. TENS combined GA is able to improve the blood flow to the liver, stomach, and reduce the apoptosis in the stomach and kidney.

[Inflammatory-modulating mechanism of transcutaneous electrical acupoint stimulation combined with general anesthesia or controlled hypotension on postoperative hippocampal neuroprotection].

OBJECTIVE: To observe the effects of transcutaneous electrical acupoint stimulation (TEAS) combined with general anesthesia or controlled hypotension on hippocampal neuronal damage and the inflammatory response in peripheral circulation and central nervous system (CNS) after surgery, and to investigate its brain protection mechanism. METHODS: Eighteen healthy male beagles aged 6 - 8 months were randomly divided into a general anesthesia group (group G), a controlled hypotension group (group C) and a compound anesthesia acupuncture group (group A), 6 cases in each group. Dogs in group G was anesthetized by isoflurane inhalation, and group C was combined with intravenous infusion of sodium nitroprusside based on isoflurane inhalation to induce hypotension, and followed surgery after achieving the target blood pressure, and group A was combined with TEAS at "Quchi" (LI 11), "Hegu" (LI 4) "Zu sanli" (ST 36) and "Sanyinjiao" (SP 6) based on controlled hypotension, and then brain tissue was taken out on the 72 h after mean arterial pressure (MAP) was returned to baseline levels. The concentration of IL-1beta,TNF-alpha in serum at different time points were detected by ELISA. The expression of IL-1beta, TNF-alpha, Bcl-2, Bax and cleaved caspase-3 were measured by immunohistochemistry, and the apoptosis of hippocampus were detected by TUNEL. RESULTS: (1) At different time points, the concentration of TNFalpha showed the trend of increase first and then decrease, while IL-1beta concentration represented a trend of decrease first and then increase in both group C and group A, but there were no significant differences in cytokine expression between the two groups (all P > 0.05). (2) The ratio of positive cells of IL-1beta, TNF-alpha and caspase-3 in CA1 and CA3 of hippocampus in both group C and A were higher than those in group G (all P < 0.01), and cytokines expression in group A were lower than those in group C (all P < 0.01), and caspase-3 in CA1 in group A was lower than that in group C (P < 0.01). The ratio of Bcl-2/Bax in both group C and A were lower than that in group G (all P < 0.01), and that in group A was higher than that in group C (P < 0.01 in CA1, P < 0.05 in CA3). (3) The apoptosis index (AI) of hippocampal neurons in both group C and A was significantly higher than that in group G (P < 0.01), while AI in CA1 in group A was lower than that in group C (P < 0.01). CONCLUSION: The TEAS can regulate the expression of inflammatory factor in hippocampus in animals undergoing general anesthesia or con trolled hypotension surgery, further improving Bcl-2/Bax ratio, inhibiting the expression of caspase-3 and reducing neuron apoptosis in hippocampus so as to play a neuroprotection.

[Effects of transcutaneous electrical acupoint stimulation combined with general anesthesia for controlled hypotension on heart function and oxidation resistance of myocardium].

OBJECTIVE: To investigate the intervention effect of transcutaneous electrical acupoint sitmulation (TEAS) on heart under limiting level of controlled hypotension. METHODS: Eighteen male Beagles were randomly divided into a general anesthesia group, a control group and an experimental group, 6 dogs in each group. All animals were applied with general anesthesia, and the animals of the control group and the experimental group were administered with combination of isoflurane and sodium nitroprusside (SNP) for controlled hypotension to 30% mean arterial pressure (30% MAP) of base line for 60 min. In the experimental group, TEAS (2 Hz/100 Hz, 6-8 mA) was applied to "Hegu" (LI4), "Zusanli" (ST 36), "Sanyinjiao" (SP 6) and "Quchi" (LI 11) from the beginning of physiological conditions stability to the end of maintained low MAP for 60 min. Creatine kinase isoenzymes MB (CK-MB) and lactate dehydrogenase (LDH) activity were detected at the base line and 2 h, 24 h, 48 h, 72 h after operation. Total superoxide dismutase (T-SOD) and malondialdehyde (MDA) in myocardium were observed at 72 h after operation. RESULTS: The peak of LDH arrived at 24 h after operation and then restored in 3 groups. Compared with basal level, the activity of LDH in controlled group at 72 h after operation was significantly increased (P < 0.05), and in the other two groups no obvious change (P > 0.05). The activity of CK-MB arrived to peak from 2 h to 24 h after operation, and then came back gradually in 3 groups. Compared with postoperative 72 h of the same group, the control group at 48 h significantly increased (P < 0.05), while the other two groups had no statistically significant difference (P > 0.05). The content of MDA at 72 h after operation in controlled group was higher significantly than that in the general anesthesia group and the experimental group (both P < 0.05). CONCLUSION: TEAS combined with anesthesia for controlled hypotension can elevate myocardial effect of anti-oxide free radical, reduce the postoperative release of LDH and CK-MB, so as to produce myocardial protection.

[Effects of transcutaneous electrical acupoint stimulation combined with general anesthesia on changes of gastric dynamics in controlled hypotension dogs].

OBJECTIVE: To observe the effect of transcutaneous electrical acupoint stimulation (TEAS) combined with general anesthesia on gastric dynamics in controlled hypotension dogs, so as to provide experimental evidence for compound acupuncture anesthesia. METHODS: Eighteen male beagle dogs were randomly divided into general anesthesia group (GA group, n = 6), general anesthesia + controlled hypotension group (GA + OHT group, n = 6) and general anesthesia combined with TEAS + controlled hypotension group (TEAS group, n = 6). The latter two groups were administered with the same anesthetics [isofluane inhalation and intravenous sodium nitroprusside (SNP)] for inducing controlled hypotension (being the 40% of the baseline level). Beagles of the GA group were not treated with controlled hypotension (the initial concentration of SNP = 1 microg/kg x min(-1), and with an increase rate of 1 microg/kg x min(-1) until the controlled hypotension phase). In the TEAS group, TEAS [2 Hz/100 Hz, (4 +/- 1) mA]was applied to "Quchi" (LI 11) , "Zusanli" (ST 36), "Hegu" (LI 4), and "Sanyinjiao" (SP 6) from the beginning of the stable physiological condition phase to the end of the controlled-low mean arterial pressure (MAP) phase. Electrogastrogram (EGG) was recorded, and serum gastrin (GAS) and motilin (MTL) contents were detected by enzyme-linked immunosorbent assay. RESULTS: Compared with the basic level, the amplitude value of EGG at 60 mm after controlled hypotension in the GA + CHT group was significantly lower (P < 0.05), while the amplitude level of EGG of the TEAS group at the time-point of MAP recovery was significantly higher than those of the GA and GA + CHT groups (P < 0.05). No significant changes were found among the 3 groups in the frequency levels of EGG. At the time-points of MAP recovery and 2 h after MAP recovery, serum MTL and GAS levels in the TEAS group were close to their basic level (P > 0.05), and serum GAS level at the time-point of 2 h after MAP recovery in the TEAS group was considerably higher than those in the GA and GA + CHT groups (P < 0.05). Twenty-four, 48 and 72 h after MAP recovery, serum GAS levels in the TEAS group were moderately (24 h and 48 h ) and significantly (72 h) higher than that of the basic level. No significant differences were found between the GA and GA + CHT groups in serum MTL and GAS levels at the time-points of 2, 24, 48 and 72 h after MAP recovery (P > 0.05). CONCLUSION: TEAS combining with general anesthesia for controlled hypotension can improve the amplitude of EGG, and serum MTL and GAS contents, favoring the recovery of gastric dynamics and the functional protection of stomach.