|Title:||Effect of electro-acupuncture and Acu-TENS during lower gastrointestinal endoscopy|
|Advisors:||Jones, Alice Y. M. (RS)|
Hong Kong Polytechnic University -- Dissertations
|Department:||Department of Rehabilitation Sciences|
|Pages:||xxvi, 256 pages : color illustrations|
|Abstract:||Colorectal cancer is the second most common cause of cancer in Hong Kong. Colonoscopy is a common procedure for examination and early screening of cancerous or malignant lesions of the large bowel. Although it is a minimally invasive procedure, it is often associated with abdominal pain and discomfort. Sedative medication commonly used to minimize the unpleasant discomfort during colonoscopy is associated with significant side effects including cardiopulmonary dysfunction. These undesirable effects can prolong recovery time and increase intervention risk in a day-case setting. Acupuncture, a technique used for management of diseases for thousands of years in China has been widely used in western countries as a treatment modality for suppression of musculoskeletal pain. Reports on the use of acupuncture for management of abdominal pain in gastroenterology are scanty and the role of acupuncture in pain relief during endoscopic procedures has not been explored. While acupuncture may be effective, it is an invasive procedure and associated side effects have been reported. Application of Transcutaneous Electrical Nerve Stimulation over acupuncture points (Acu-TENS), a non-invasive modality for pain relief has received increasing attention in recent years. The aims of this thesis were therefore to explore the role of electro-acupuncture and Acu-TENS, and their possible associated mechanism, in relief of discomfort during colonoscopy. The investigatory work reported in this thesis was conducted in two phase. Phase I of the thesis involved two pilot studies which explored the effect of electro-acupuncture and Acu-TENS on the relief of rectal discomfort induced by a Barostat. The Barostat allows controlled air-inflation in the rectal region and is designed to investigate visceral pain by mimicking the initial colonoscopy procedure. Phase II of the thesis explored the effect of electro-acupuncture and Acu-TENS on the consumption of analgesic medication in subjects receiving a colonoscopy procedure. The first pilot study involved forty healthy subjects, who were scheduled for a voluntary and free colonoscopy screening for bowel cancer in a public hospital. Subjects were invited to participate in a "Barostat trial¨ in the morning prior to the scheduled colonoscopy and consented subjects were randomized to receive either electro-acupuncture (EA) or sham acupuncture (SA) at Hegu (LI-4), Neiguan (PC-6) and Zusanli (ST-36) for forty-five minutes prior to the Barostat trial. SA was similar to EA except that short studs instead of actual acupuncture needles were used and there was no puncture of the skin. The Barostat trial involved insertion of a balloon catheter into the rectum with a standardized, incremental (4 mmHg) rise in balloon inflation pressure. Colorectal discomfort experienced with each increment rise in pressure was assessed by a visual analogue (VAS) and a 4-point subjective discomfort scale. Blood beta-endorphin levels were measured before and immediately after electro-acupuncture, and at an inflation pressure of 24 mmHg, as well as at the maximum pressure tolerated. Results of this pilot study showed that onset of rectal discomfort was reported at a higher inflation pressure in the EA group compared to the SA group (43.5 mmHg ± 6.6 mmHg and 35.6 mmHg ±8.8 mmHg, respectively, p = 0.007)). Twelve subjects in the EA group tolerated the maximum inflation pressure (48 mmHg) compared to only 4 in the SA group. Beta-endorphin levels increased significantly in the EA group but not in the SA group (1.25 ± 0.45 ng/ml and 0.79 ± 0.17 ng/ml respectively, p<0.001). This pilot study demonstrated that electro-acupuncture is safe and effective in reducing colorectal discomfort induced by the Barostat. The results of this pilot study affirm a need to further explore the role of electro-acupuncture during a colonoscopy procedure. The second pilot study was conducted in a similar manner as the first study, except that Acu-TENS was used as the intervention instead of electro-acupuncture. Another 40 healthy subjects were randomized to receive 45 minutes of either Acu-TENS or placebo-TENS (placement of electrodes over same sites but no electrical output from the TENS unit) over acupuncture points Hegu (LI-4), Neiguan (PC-6) and Zusanli (ST-36). Results of this second study showed that perception threshold levels for discomfort were higher in the Acu-TENS group when compared to the placebo group, but the difference reached statistical significance only with the sensations "urge to defecate" and "pain" (p=0.043). The pressures recorded at the point when "pain" sensation was reported were 36.0 ± 4.2 mmHg in the Acu-TENS group and 30.5 ± 4.3 mmHg in the placebo group (p=0.002). A higher number of participants in the Acu-TENS group tolerated higher distension pressures (>40 mmHg) (65% in Acu-TENS vs 25% in placebo, p=0.02) compared to the placebo group. The plasma beta-endorphin levels of the Acu-TENS group were significantly higher than that of the placebo group. These findings suggested Acu-TENS is a safe and effective modality in reduction of colorectal pain and probably with a mechanism that is associated with an increase in beta-endorphin level|
The positive and encouraging results from these two pilot studies form the foundation of the two main studies which explored the effect of electro-acupuncture and Acu-TENS during the actual colonoscopy procedure and in a larger population sample. The third study reported in this thesis involved 128 consecutive asymptomatic subjects scheduled for colonoscopy screening in a regional hospital. Recruited subjects were randomized to receive either electro-acupuncture (EA) or sham acupuncture (SA) (short stud instead of needle) over acupuncture points Hegu (LI-4), Neiguan (PC-6) and Zusanli (ST-36) for 45 minutes prior to the colonoscopy procedure. Following the normal routine for patients undergoing a colonoscopy, a patient controlled mixture of propofol and alfentanil was established (Patient Controlled Analgesia -PCA). Outcome measures used included the dosage of the analgesic mixture consumed, subjective pain scores during colonoscopy, the subject's "satisfaction" score for the procedure, the endoscopist's satisfaction score for the procedure and the caecal intubation time. All outcome measures were recorded by an independent assessor who was blinded to the randomization allocation. Results of this study demonstrated that the mean dose of analgesics used in EA group was significantly lower than in the SA group (0.19 mg/kg vs. 0.61 mg/kg, p<0.001). Subjective pain score (2.7 vs. 4.5, p<0.001) was lower and satisfaction score (9.4 vs. 8.8, p=0.016) was higher in the EA group compared to the SA group. Caecal intubation was also significantly faster in the EA group (7.5 mins vs. 9.6 mins in SA group, p=0.015). Multiple linear regression analysis showed that electro-acupuncture was an independent predictor of a lower analgesia dose (coefficient B -0.383, p<0.001). This study showed that use of electro-acupuncture allowed a significant reduction in consumption of sedation, as well as an effective lowering of subjective pain scores in subjects undergoing colonoscopy. The 4th and final study presented in this thesis involved another 135 consecutive asymptomatic patients undergoing first-time elective colonoscopy. Subjects were randomized to receive either Acu-TENS (n = 68) or placebo-TENS (n = 67) before colonoscopy. Similar acupoints, Hegu (LI-4), Neiguan (PC-6) and Zusanli (ST-36) to the other studies were used. A propofol/alfentanil PCA mixture was used for sedation/analgesia in both groups. All subjects and the endoscopists were blinded to the treatment allocation and the outcome measures were similar to those used previously. The results showed that the mean analgesic/sedative dose was significantly lower in the Acu-TENS group compared to the placebo-TENS group (0.25 mg/kg vs. 0.88 mg/kg; p <0.001). The Acu-TENS group had a lower mean pain score (4.0 vs. 5.6; p=0.006) compared to the placebo-TENS group, and a higher mean satisfaction score (9.5 vs. 8.9; p=0.015). A trend toward shorter caecal intubation time also was observed in the Acu-TENS group compared with the placebo-TENS group but this did not reached statistical significance (10.2 mins vs. 12.3 mins; p=0.061). Endoscopists in the Acu-TENS group reported a higher mean satisfaction score than those in the placebo-TENS group (8.0 vs. 6.8; p<0.001). Multiple linear regression analysis revealed that shorter procedure time (p<0.001), absence of looping (p=0.036), older age (p=0.038) and male gender (p=0.042) were independent predictors of lower PCA consumption during colonoscopy in the Acu-TENS group (p<0.001). This study suggests that Acu-TENS is more effective than placebo-TENS in reducing procedure-related pain during the colonoscopy procedure. In summary, the work involved in this thesis showed that electro-acupuncture and Acu-TENS are associated with significantly reduced consumption of analgesic medication and more effective pain relief in subjects undergoing colonoscopy. These modalities may be considered a useful adjunct to minimize discomfort during the colonoscopy procedure. Further investigations on comparing the role of electro-acupuncture and the non-invasive Acu-TENS are warranted.
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