Anesth Analg 2003;97:925-926
© 2003 International Anesthesia Research Society
LETTERS TO THE EDITOR
Tender Active Acupoint Is Not an Ideal Control for Acupressure Study
Gregory Chernyak, MD
Department of Anesthesiology, School of Medicine, University of Louisville, Louisville, KY
To the Editor:
Fassoulaki et al (1) selected a control point located 2 cm lateral to the left eyebrow. This location corresponds to the extra meridian point Taiyang (2) and for that reason alone is not an ideal control point. Furthermore, the volunteers experienced an unpleasant feeling during acupressure on the control point, whereas acupressure on the Yintang point (extra 1) was not associated with this feeling. The level of discomfort was so great that volunteers were not able to tolerate pressure on the control point long enough to match the duration of treatment on the extra 1 point. This probably increased the anxiety and stress and created uneven treatment conditions for the study days. It is not quite clear, then, why the authors used this point as their control.
Acupressure on either point could have produced sedation and reduced anxiety owing to "treatment expectation" placebo effect associated with endogenous opioid release (3,4). However, painful stimulation of the control point might have aroused (5) the subject as stress-mediated catecholamines release (6) can override the relaxing effect.
In my opinion, the results of this study would be more convincing if the authors had chosen another intact non-tender point on the forehead as the control point.
References:
- Fassoulaki A, Paraskeva A, Patris K, et al. Pressure applied on the extra 1 acupuncture point reduces bispectral index values and stress in volunteers. Anesth Analg 2003; 96: 885–90.[Abstract/Free Full Text]
- Cheng J. Anatomical atlas of Chinese acupuncture points. Jinan, China: Shandong Science and Technology Press, 1990.
- ter Riet G, de Craen AJ, de Boer A, Kessels AG. Is placebo analgesia mediated by endogenous opioids? A systematic review. Pain 1998; 76: 273–5.[Web of Science][Medline]
- Benedetti F, Arduino C, Amanzio M. Somatotopic activation of opioid systems by target-directed expectations of analgesia. J Neurosci 1999; 19: 3639–48.[Abstract/Free Full Text]
- Andrzejowski J, Sleigh JW, Johnson IA, Sikiotis L. The effect of intravenous epinephrine on the bispectral index and sedation. Anaesthesia 2000; 55: 761–3.[Web of Science][Medline]
- Carrasco GA, Van de Kar LD. Neuroendocrine pharmacology of stress. Eur J Pharmacol 2003; 463: 235–72.[Web of Science][Medline]
Response
Argyro Fassoulaki, MD, PhD, DEAA
Department of Anesthesiology, Aretaieion Hospital, Athens, Greece
In Response:
As we describe in the Methods section of our article (1), the control point was located 2 cm from the lateral of the eyebrow, and this location is above the Taiyang acupuncture point. Underneath the control point, the bone protrudes rather, and this may be a reason for the unpleasant feeling. According to figures and descriptions, the Taiyang point lies between the lateral end of the eyebrow and the outer canthus (2) (Figure 1 of the article) or at the level of the outer canthus (3) (Figure 2 of the article). Besides, as most of the acupuncture points, it lies in a depression not on a protruding bonny area. So, we did not apply pressure on another acupuncture point. It is quite clear why we used this control point. As described in the Methods section, the location of the control point was selected to be close to the BIS sensor, so that possible interferences of pressure application with the BIS sensor and signal would be observed in both the treatment and the control group.
The assumption by Dr. Chernyak, that painful stimulation of the control point might have aroused the subject as stress-mediated catecholamines release can override the relaxing effect, is not accurate. Volunteers described an unpleasant feeling, not pain, and catecholamine levels were not measured. Painful stimulation and unpleasant feeling are not identical concepts. We limited the pressure duration to 5 min for two reasons: a) these volunteers were kindly offered without any reward, and b) a longer lasting unpleasant feeling might have an impact on recruiting more volunteers.
Uneven treatment conditions apply to every study using a placebo treatment versus an effective treatment. The acupressure application on the extra 1 point was assessed also by BIS, which is an objective measurement versus the feeling of reduced stress and tension, which is subjective.
About treatment expectation and placebo effect, despite the unpleasant feeling due to pressure, the level of anxiety was also reduced in the control group by 14% (Figure 4 of the article), but this reduction was significantly less when compared with the 50% reduction in the treatment group. Finally, we wish to emphasize that due to BIS sensor, which occupies a large area on the forehead, and due to the bone underneath the forehead, which is sensitive to pressure application, an ideal control point is not feasible.
References
- Fassoulaki A, Paraskeva A, Patris K, et al. Pressure applied on the extra 1 acupuncture point reduces bispectral index values and stress in volunteers. Anesth Analg 2003; 96: 885–90.
- Liangyue D, Yijun G, Shuhui H, et al. Acupoints of the Du and the Ren meridians and the extraordinary points. In: Cheng Xinnong, ed. Chinese acupuncture and moxibustion. 1st ed. Beijing, China: Foreign Language Press, 1987: 232.
- Stux G. Extra points. In: Stux G, Pomeranz B, eds. Basics of acupuncture. 2nd ed. New York: Springer-Verlag, 1990: 177.
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