In traditional Chinese medicine, moxibustion is a local thermal therapy that is used for several conditions. Quantifying the effects of moxibustion therapy has been difficult because the treatment temperature depends on the physician's experience, and the temperature distribution in the target area is not uniform. This prospective observational study aims to quantify the effect of local thermal stimulation to the abdomen. We developed a heat transfer control device (HTCD) for local thermal stimulation. Twenty-four healthy subjects were enrolled and they underwent abdominal thermal stimulation to the para-umbilical region with the device for 20 min. Blood flow volume in the superior mesenteric artery (SMA) and brachial artery (BA), the heart rate and the blood pressure were measured at rest, 15 min after starting thermal stimulation and 10, 20, 30 and 40 min after completing thermal stimulation. Blood flow parameters were measured by high-resolution ultrasound. In the SMA, blood flow volume was significantly increased during thermal stimulation (
Recently, thermal therapy has been used for a number of conditions such as inflammatory bowel diseases, chronic heart failure, chronic pain, depressive state and chronic obstructive pulmonary disease [
Under normal conditions, the superior mesenteric artery (SMA) blood flow pattern and velocity show large variations due to the metabolic activity of the bowel [
There have been no reports about SMA blood flow changes in relation to moxibustion therapy. Therefore, this study was performed to evaluate the changes of SMA blood flow volume with abdominal ultrasound after thermal stimulation with an HTCD.
We enrolled 24 healthy male subjects, who had a mean ± SD age of 31.2 ± 6.9 years (range 21–44 years). The study protocol was approved by the Ethics Committee of Tohoku University Graduate School of Medicine. Written informed consent to participation was given by all subjects.
To quantify the heat delivered, we developed an HTCD instead of moxibustion for local thermal stimulation (Figure
HTCD is composed of a heating disk, temperature sensor and a heat controller.
This is a prospective observational study. We performed abdominal thermal stimulation at the para-umbilical region with an HTCD for 20 min and measured SMA hemodynamics by ultrasound from rest until 40 min after thermal stimulation. To compare intestinal and peripheral blood flow volume, we measured the hemodynamics of the brachial artery (BA) simultaneously. An outline of the study is shown in Figure
Outline of the study. Thermal stimulation was applied to the para-umbilical region with an HTCD for 20 min. Hemodynamics were measured at rest (baseline), during thermal stimulation (after 15 min) and at 10, 20, 30 and 40 min after the completion of thermal stimulation.
All subjects were examined in the morning after an overnight fast (at least 8 h). The subject rested in the supine position in a quiet, air-conditioned room (temperature 25-26°C). Three monitoring electrocardiographic electrodes were attached to the chest. Blood pressure was measured in the left upper arm with an oscillometer (HEM-9000AI, Omron Healthcare Co., Ltd, Kyoto, Japan). SMA and right BA hemodynamics were measured with an ultrasound system (Prosound
Hemodynamic data obtained by ultrasound. (a) VD of the SMA, (b) blood flow velocity of the SMA, (c) vessel diameter of the BA and (d) blood flow velocity of the BA.
Hemodynamic parameters:
VD CSA = (VD/2)2 × Peak systolic velocity (PSV) End-diastolic velocity (EDV) Resistive index (RI) = (PSV−EDV)/PSV Pulsatility index (PI) = (PSV−EDV)/MV Mean flow velocity (MV) Blood flow volume = CSA × MV [
Each parameter was recorded three times in three different cardiac cycles and averaged for each subject in an effort to minimize random errors [
After positioning the ultrasound system, the subjects rested in the supine position for 10 min. Abdominal thermal stimulation was done at the para-umbilical region with the HTCD for 20 min from a temperature of 40°C. After 5 min, if subjects were used to the heat, the temperature was increased to 41°C. After thermal stimulation for 20 min, the device was removed.
We measured the SMA and BA hemodynamics, heart rate and blood pressure at rest (baseline), after 15 min of thermal stimulation, and 10, 20, 30 and 40 min after the end of thermal stimulation (Figure
Statistical analysis was performed with SPSS software (version 16.0, SPSS Japan Inc., Tokyo, Japan). Repeated measures analysis of variance with a Tukey post hoc test was used for statistical comparison with baseline. Although 24 subjects were enrolled in our study, three subjects were excluded because their examinations were technically unsuccessful (the SMA could not be identified clearly due to intestinal gas). As a result, 21 subjects were included in the final analysis. Results are presented as the medians and quartile (first and third), the means and SEM and 95% confidence intervals.
The hemodynamic parameters in the SMA and BA are summarized in Tables
Summary of hemodynamic parameters.
Parameter | Baseline | During TS | 10 min after TS | 20 min after TS | 30 min after TS | 40 min after TS |
---|---|---|---|---|---|---|
VD (mm) | ||||||
Median (first, third quartile) | 6.87 (6.4, 7.17) | 7.0 (6.67, 7.3) | 7.05 (6.65, 7.53) | 7.13 (6.7, 7.47) | 7.0 (6.6, 7.2) | 6.97 (6.55, 7.3) |
Mean (SEM) | 6.79 (0.14) | 6.69 (0.14)** | 7.01 (0.15)** | 6.97 (0.15)** | 6.92 (0.14)* | 6.84 (0.15) |
95% CI | 6.52–7.06 | 6.69–7.23 | 6.70–7.28 | 6.68–7.26 | 6.64–7.20 | 6.55–7.14 |
PSV (cm/s) | ||||||
Median (first, third quartile) | 144.3 (121.3, 168.2) | 163.3 (146.3, 194.2) | 166.7 (149.6, 191.7) | 153.4 (139.6, 205.7) | 156.75 (132.5, 181.8) | 156.4 (134.8, 192.6) |
Mean (SEM) | 151.3 (9.1) | 178.3 (1.04)** | 170.0 (12.1) | 169.8 (9.8) | 162.4 (9.7) | 161.2 (8.5) |
95% CI | 133.5–169.1 | 157.9–198.8 | 146.4–193.7 | 150.6–189.1 | 143.4–181.4 | 145.0–177.6 |
EDV (cm/s) | ||||||
Median (first, third quartile) | 6.5 (1.35, 13.9) | 10.7 (5.9, 15.8) | 8.7 (2.2, 13.2) | 9.9 (0.3, 14.7) | 6.6 (0.0, 14.8) | 7.4 (0.0, 13.6) |
Mean (SEM) | 10.7 (2.7) | 14.9 (3.7) | 12.3 (3.8) | 12.0 (3.2) | 10.5 (2.8) | 11.0 (3.1) |
95% CI | 5.3–16.2 | 7.6–22.1 | 4.9–19.7 | 5.8–18.3 | 5.0–16.0 | 5.1–17.0 |
RI | ||||||
Median (first, third quartile) | 1 (0.94, 1.04) | 0.98 (0.92, 1.00) | 0.96 (0.92, 1.00) | 0.97 (0.93, 1.00) | 1 (0.92, 1.00) | 0.98 (0.92, 1.00) |
Mean (SEM) | 0.98 (0.02) | 0.96 (0.02) | 0.95 (0.01) | 0.96 (0.02) | 0.97 (0.02) | 0.96 (0.02) |
95% CI | 0.95–1.01 | 0.92–1.00 | 0.92–0.98 | 0.93–0.99 | 0.94–1.00 | 0.93–0.99 |
PI | ||||||
Median (first, third quartile) | 4.57 (3.00, 5.26) | 4 (3.41, 4.93) | 3.98 (3.23, 4.83) | 3.84 (3.43, 4.99) | 4.16 (3.48, 4.95) | 4 (3.39, 5.35) |
Mean (SEM) | 4.29 (0.40) | 4.21 (0.28) | 4.11 (0.26) | 4.30 (0.29) | 4.30 (0.27) | 4.36 (0.32) |
95% CI | 3.51–5.07 | 3.66–4.76 | 3.60–4.61 | 3.73–4.87 | 3.77–4.84 | 3.74–4.98 |
MV (ml/s) | ||||||
Median (first, third quartile) | 34.4 (28.5, 38.6) | 39.8 (34.2, 44.3) | 38.6 (31.7, 45.7) | 36.7 (30.1, 46.4) | 33.5 (29.5, 41.3) | 33.5 (28.9, 38.7) |
Mean (SEM) | 36.6 (3.6) | 44.5 (4.6)** | 44.6 (4.8)** | 42.0 (4.3)* | 49.66 (3.7) | 39.0 (3.9) |
95% CI | 29.6–43.7 | 35.5–53.5 | 35.1–54.1 | 33.6–50.3 | 32.3–47.0 | 31.5–46.6 |
BFV (ml/min) | ||||||
Median (first, third quartile) | 747.1 (565.1, 891.6) | 814 (755.0, 1066.7) | 847.3 (684.6, 1098.8) | 827.7 (633.7, 1058.7) | 818 (566.0, 960.3) | 751.6 (577.5, 859.3) |
Mean (SEM) | 822.1 (109.3) | 1045.0 (143.5)** | 1062.8 (153.6)** | 986.3 (129.8)* | 913.7 (11.7) | 882.1 (119.3) |
95% CI | 623.7–1020.4 | 784.6–1035.4 | 784.1–1341.6 | 750.8–1221.8 | 711.0–116.3 | 671.7–1092.5 |
Hemodynamic parameters measured by ultrasound are shown for the SMA. The values represent medians and quartile (first and third), means and SEM and 95% CI. TS, thermal stimulation; BFV, blood flow volume.
Summary of hemodynamic parameters.
Parameter | Baseline | During TS | 10 min after TS | 20 min after TS | 30 min after TS | 40 min after TS |
---|---|---|---|---|---|---|
VD (mm) | ||||||
Median (first, third quartile) | 4.4 (3.85, 4.6) | 4.6 (4.0, 4.8) | 4.47 (4.07, 4.77) | 4.45 (4.0, 4.73) | 4.55 (3.87, 4.7) | 4.45 (3.85, 4.76) |
Mean (SEM) | 4.35 (0.11) | 4.56 (0.13)** | 4.47 (0.12) | 4.48 (0.11)* | 4.47 (0.13) | 4.40 (0.13) |
95% CI | 4.13–4.58 | 4.31–4.80 | 4.24–4.71 | 4.23–4.70 | 4.22–4.72 | 4.16–4.64 |
PSV (cm/s) | ||||||
Median (first, third quartile) | 76.8 (64.9, 95) | 77.8 (70, 87.8) | 82.1 (62, 93) | 74.375 (58.2, 82.2) | 74.7 (62.2, 87.6) | 73 (57.5, 78.1) |
Mean (SEM) | 80.2 (4.0) | 80.0 (4.0) | 79.0 (4.3) | 74.4 (3.5) | 73.3 (3.5)* | 70.1 (3.5)** |
95% CI | 7.32–88.0 | 72.1–87.9 | 70.6–87.4 | 67.5–81.3 | 66.5–80.2 | 63.3–76.9 |
EDV (cm/s) | ||||||
Median (first, third quartile) | 16.7 (14.0, 21.2) | 16.9 (14.7, 20.8) | 16.6 (12.2, 20.7) | 14.8 (12.0, 20.2) | 14.2 (12.2, 17.1) | 11.3 (9.3, 14.2) |
Mean (SEM) | 17.9 (1.3) | 17.3 (1.2) | 16.8 (1.2) | 15.6 (1.1) | 14.8 (1.1)** | 11.6 (0.9)** |
95% CI | 15.5–20.4 | 15.0–19.6 | 14.4–19.2 | 13.4–17.8 | 12.6–17.1 | 9.9–13.3 |
RI | ||||||
Median (first, third quartile) | 0.83 (0.75, 0.90) | 0.80 (0.75, 0.86) | 0.79 (0.76, 0.85) | 0.81 (0.78, 0.85) | 0.83 (0.80, 0.96) | 0.89 (0.95) |
Mean (SEM) | 0.87 (0.04) | 0.85 (0.03) | 0.85 (0.04) | 0.87 (0.04) | 0.90 (0.04) | 0.92 (0.03)** |
95% CI | 0.79,–0.94 | 0.77–0.92 | 0.78–0.92 | 0.79–0.94 | 0.82–0.98 | 0.87–0.98 |
PI | ||||||
Median (first, third quartile) | 2.45 (1.98, 3.18) | 2.33 (1.97, 2.68) | 2.25 (1.96, 2.85) | 2.33 (2.05, 2.88) | 2.64 (2.20, 3.48) | 3.26 (2.77, 3.76) |
Mean (SEM) | 4.22 (1.05) | 3.29 (0.71) | 3.32 (0.67) | 3.58 (0.83) | 3.65 (0.69) | 3.62 (0.50) |
95% CI | 2.17–6.27 | 1.90–4.68 | 1.99–4.63 | 1.96–5.21 | 2.29–5.01 | 2.66–4.58 |
MV (ml/s) | ||||||
Median (first, third quartile) | 28.4 (20.7, 34.3) | 29.0 (19.4, 34.6) | 28.8 (20.4, 33.0) | 25.9 (19.9, 32.2) | 24.5 (16.2, 28.7) | 22.0 (15.5, 25.4) |
Mean (SEM) | 27.4 (2.4) | 27.3 (2.2) | 26.8 (2.3) | 25.1 (2.1) | 23.4 (1.9)** | 20.9 (1.6)** |
95% CI | 22.6–32.1 | 23.0–31.5 | 22.3–31.2 | 21.1–29.2 | 19.5–27.2 | 17.9–23.9 |
BFV (ml/min) | ||||||
Median (first, third quartile) | 248.2 (204.3, 326.3) | 262.8 (211.1, 365.8) | 271.3 (190.8, 329.2) | 242.7 (188.4, 314.0) | 218.4 (154.0, 273.4) | 178.2 (136.6, 247.1) |
Mean (SEM) | 246.3 (25.2) | 268.2 (26.4) | 255.4 (25.2) | 240.4 (24.1) | 220.8 (22.2) | 195.3 (21.1)** |
95% CI | 200.6–292.0 | 220.3–316.1 | 209.8–301.1 | 196.8–284.0 | 180.5–261.1 | 158.1–232.5 |
Hemodynamic parameters measured by ultrasound are shown for the brachial artery. The values represent medians and quartile (first and third), means and SEM and 95% CI. TS, thermal stimulation; BFV, blood flow volume.
The changes of VD, MV and blood flow volume in the SMA and BA are shown in Figures
Hemodynamic changes in the SMA. (a) Change of vessel diameter, (b) change of MV and (c) change of blood flow volume. The values represent the means and SEM.
Hemodynamic changes in the BA. (a) Change of vessel diameter, (b) change of mean flow velocity and (c) change of blood flow volume. The values represent the means and SEM.
PSV in the SMA showed a significant increase during thermal stimulation (
The blood pressure and heart rate are shown in Table
Summary of hemodynamic parameters.
Parameter | Baseline | During TS | 10 min after TS | 20 min after TS | 30 min after TS | 40 min after TS |
---|---|---|---|---|---|---|
HR (beats/min) | ||||||
Median (first, third quartile) | 61 (54, 64) | 57 (54, 67) | 58 (54, 61) | 56 (53, 61) | 56 (54, 62) | 58 (53.3, 60.5) |
Mean (SEM) | 59.6 (1.9) | 60.0 (2.0) | 58.5 (1.6) | 57.3 (1.8) | 58.7 (1.7) | 58 (1.8) |
95% CI | 56.0–63.3 | 56.1–63.8 | 55.2–61.7 | 53.9–60.8 | 55.4–62.0 | 54.8–61.54 |
Syst BP (mmHg) | ||||||
Median (first, third quartile) | 115 (106, 125) | 116 (109, 125) | 114 (108, 127) | 118 (111, 124) | 116 (113, 125) | 118.5 (112, 127) |
Mean (SEM) | 117.3 (2.4) | 117.9 (2.6) | 117.5 (2.6) | 118.9 (2.5) | 120.4 (2.9) | 121.9 (3.1)* |
95% CI | 113.0–121.5 | 113.5–122.2 | 113.2–121.7 | 114.3–123.6 | 115.6–125.5 | 117.1–126.7 |
Dia BP (mmHg) | ||||||
Median (first, third quartile) | 69 (63, 75) | 66 (63, 80) | 66 (62, 72) | 68 (62, 78) | 69 (62, 76) | 69.5 (63.8, 77.3) |
Mean (SEM) | 69.8 (2.2) | 69.9 (2.2) | 68.1 (2.2) | 70.6 (2.4) | 70.7 (2.6) | 72.1 (2.5) |
95% CI | 65.5–74.0 | 65.6–74.2 | 63.9–72.4 | 66.0–75.2 | 65.5–75.8 | 67.3–76.9 |
Blood pressure and heart rate are also shown. The values represent medians and quartile (first and third), means and SEM and 95% CI. TS, thermal stimulation; HR, heart rate; Syst BP, systolic blood pressure; Dia BP, diastolic blood pressure; CI, confidence interval.
There were no complications such as local burns, pain, discomfort or other problems that needed treatment.
This is the first report about the changes of blood flow volume for SMA and BA by local thermal stimulation with an ultrasound system. In SMA, blood flow volume significantly increased during thermal stimulation, as well as at 10 and 20 min after stimulation. In BA, blood flow volume significantly decreased 40 min after stimulation.
We expressed the changes of SMA hemodynamics with an ultrasound system. The SMA supplies blood to the duodenum, small bowel, colon and rectum. Blood flow volume in the SMA can be altered by several diseases, such as Crohn's disease, ulcerative colitis, enteroperitoneal tuberculosis and appendicitis [
Hypothesis of mechanisms for increasing blood flow volume in SMA compared with BA.
The SMA blood flow reflects mesenteric flow, whereas BA blood flow reflects peripheral flow. The present study showed that the blood flow volume of the SMA increased significantly during thermal stimulation and up to 20 min after thermal stimulation, while it decreased 40 min after thermal stimulation in the BA. According to the blood flow velocity curve of the SMA and BA, the interarterial differences of blood pressure between SMA and BA can be calculated. The difference significantly increased during thermal stimulation (95% confidence interval (95% CI) 0.5–3.9 mmHg;
Our hypothesis is that the change of blood flow volume by thermal stimulation with HTCD is related not to the direct thermal energy, but to the reaction of vasodilator neurons. The thermal energy in the skin is continuously carried off by blood circulation in the skin, fat and muscles in the human body. An increase in the tissue temperature causes an activation of the metabolism. The increase in the metabolism and subsequent increase in perfusion due to increasing temperatures are modeled according to a well-known
In the present study, we demonstrated the change of blood flow volume by HTCD. To our knowledge, this is the first report about the effect of abdominal thermal stimulation on blood flow in the SMA and BA. This trial was a pilot study with a small sample size, and no control and randomization. The subjects were all men. However, the pattern of change of blood flow volume in SMA and BA was same in the subjects, except for one. We supposed that the blood flow volume did not occur by chance. We would like to undertake this study further in both men and women, with a larger sample size, control group and randomization.
Mesenteric ischemia results from decreased blood flow to the bowel, causing several symptoms such as pain, nausea and vomiting. Non-occlusive mesenteric ischemia is an acute mesenteric circulatory disorder which is induced by vasospasm [
When SMA hemodynamics during thermal stimulation was measured by ultrasound, the acceleration of intestinal peristalsis was observed along with an increase in blood-flow volume. Thus, thermal stimulation not only increases the blood-flow volume, but also improves intestinal motility. Abdominal thermal therapy may be useful for patients with low SMA blood flow, paralytic ileus or chronic constipation. In the future, we hope to study the effect of thermal stimulation on patients with such disorders.
Moxibustion is often combined with acupuncture; however, in the West it is not often used because of the odor from the burning moxa. HTCD can heat the target area uniformly without any odor or the dangers associated with a fire. Thus, abdominal thermal therapy with an HTCD may be useful for patients with intestinal disorders instead of moxibustion. We would like to undertake further studies to clarify the effect of local thermal stimulation, for not only the abdomen but also for other areas.
In conclusion, we could measure the effect of local thermal stimulation quantitatively with an HTCD and high-resolution ultrasound. Thermal stimulation of the para-umbilical region could increase blood flow in the SMA 20 min after stimulation in healthy subjects.
Special Coordination Funds for Promoting Science and Technology from the Japanese Ministry of Education, Culture, Sports, Science and Technology.
The authors would like to thank all the participants and
especially Ms Setsu Watanabe for drawing Figure