RESUMEN
OBJECTIVE: To observe the effect of transcutaneous electrical acupoint stimulation (TEAS) on ileus-postope-rative gastrointestinal functions and plasma ghrelin, motilin, and gastrin contents, and heart rate variability (HRV) in patients undergoing gastrointestinal surgery, so as to explore the interaction of vagus-brain-gut peptide. METHODS: A total of 58 patients undergoing elective gastrointestinal surgery were randomly assigned to TEAS (n=29) and sham-TEAS group (n=29, patients had no subjective sensation to 1 mA TEAS, thus, being considered to be sham-TEAS). TEAS (2 Hz/100 Hz, 6-8 mA for LI 4-PC 6, 12-18 mA for ST 36-SP 6) was applied to bilateral Hegu (LI 4)-Neiguan (PC 6) from 30 min pre-operation to the end of the operation and to bilateral LI 4-PC 6 and Zusanli (ST 36)-Sanyinjiao (SP 6) for 30 minutes twice daily in 3 consecutive post-operative days. ECGs of 12 leads were recorded to analyze different parameters of HRV from 2 days before and 4 days after surgery. Plasma ghrelin, motilin and gastrin contents were assayed by radioimmunoassay, and the patients' first bowel sound, first independent walk, first flatus, first solid food-intake and first defecation were recorded to evaluate the recovery state of gastrointestinal motility. RESULTS: Postoperative gastrointestinal motility:compared with the sham-TEAS group, the first bowel sound and the first defecation after surgery appeared apparently earlier in the TEAS group (P<0.05), but no significant differences were found between the two groups at the time of the first independent walk, first flatus and the first solid food-intake in patients undergoing gastrointestinal surgery. Plasma brain-gut peptides:the plasma ghrelin and motilin contents 4 days post-surgery were significant increased in the TEAS group than in the sham-TEAS group (P<0.05). No significant difference was found between the two groups in plasma gastrin contents (P>0.05). HRV domains:in comparison with pre-surgery, the levels of low frequency (LF) and high frequency (HF) of frequency domain (FD) and root mean square of successive differences (rMSSD) of the time domain (TD) of HRV 4 days after surgery were significantly decreased in the sham-TEAS group (P<0.05), but no significant changes were found in both FD and TD domains of the TEAS group 4 days after surgery (P>0.05). Compared with the sham-TEAS group, the HF and rMSSD levels were significantly increased in the TEAS group 4 days after the surgery (P<0.05). No significant differences were found between the two groups in the levels of very low frequency, LF and LF/HF levels of FD, and standard deviation of NN (beat-to-beat) intervals, the standard deviation of the average NN intervals and the proportion of NN 50 (the number of pairs of successive NNs that differ by more than 50 ms) divided by total number of NNs of TD. CONCLUSIONS: TEAS can promote gastrointestinal activities (i.e., reducing the time spending of first bowel sound and the first defecation) in gastrointestinal surgery patients, which may be related to its effects in up-regulating ghrelin and motilin contents and parasympathetic activity.