Scholarly article on topic 'Electrical stimulation of acupoint combinations against deep venous thrombosis in elderly bedridden patients after major surgery'

Electrical stimulation of acupoint combinations against deep venous thrombosis in elderly bedridden patients after major surgery Academic research paper on "Clinical medicine"

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Abstract of research paper on Clinical medicine, author of scientific article — Lili Hou, Cuiping Chen, Lei Xu, Peihao Yin, Wen Peng

Abstract Objective To compare the effects of electrical stimulation of different acupoint combinations among postoperative bedridden elderly patients on hemorheology and deep venous blood flow velocity and investigate the role of electrical stimulation against deep vein thrombosis (DVT). Methods From November 2010 to October 2011, a total of 160 elderly bedridden patients after major surgery were divided into the conventional care group, invigorating and promoting Qi group, blood-activating and damp-eliminating group, and acupoint-combination stimulation group. Whole blood viscosity, plasma viscosity, D-dimer levels, lower limb skin temperature, lower limb circumference, and flow velocities of the external iliac vein, femoral vein, popliteal vein, and deep calf veins in all patients were documented and compared among the four groups. Results Whole blood viscosity, plasma viscosity, D-dimer levels, and lower limb circumference were significantly reduced in the blood-activating and damp-eliminating group compared with the conventional care group (P<0.05) and were almost equal to those in the acupoint-combination stimulation group (P>0.05). Lower limb venous flow velocities were accelerated in the invigorating and promoting Qi group compared with the other groups, excluding the acupoint-combination stimulation group (P<0.05). Conclusion Hemorheological indices in postoperative bedridden elderly patients were improved after combined electrical stimulation at Yinlingquan (SP 9) and Sanyinjiao (SP 6). Combined electrical stimulation at Zusanli (ST 36) and Taichong (LR 3), on the other hand, accelerated lower limb venous flow.

Academic research paper on topic "Electrical stimulation of acupoint combinations against deep venous thrombosis in elderly bedridden patients after major surgery"

JTCM

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JTradit Chin Med 2013 April 15; 33(2): 187-193 ISSN 0255-2922 © 2013 JTCM. All rights reserved.

CLINICAL STUDY

Electrical stimulation of acupoint combinations against deep venous thrombosis in elderly bedridden patients after major surgery

Lili Hou, Cuiping Chen, Lei Xu, Peihao Yin, Wen Peng

Lili Hou, Department of Nursing, Shanghai Pulmonary Hospital, Shanghai 200433, China

Cuiping Chen, Department of Nursing, Tenth People's Hospital of Tongji University, Shanghai 200072, China Lei Xu, Department of Nursing, Putuo Hospital, Shanghai University of Chinese Medicine, Shanghai 200062, China Peihao Yin, Department of General Surgery, Putuo Hospital, Shanghai University of Chinese Medicine, Shanghai 200062, China

Wen Peng, Department of Kidney, Putuo Hospital, Shanghai University of Chinese Medicine, Shanghai 200062, China Supported by the Construct Program of the Key Discipline of State Administration of Traditional Chinese Medicine of the People's Republic of China and by the Science and Technology Development Fund of the Shanghai Municipal Public Health Bureau (No. 2011Y200, 2008Y127,and 2005L019A) Correspondence to: Prof. Wen Peng, Department of Kidney, Putuo Hospital, Shanghai University of Chinese Medi-cine,Shanghai200062,China.wenpeng1968@yahoo.com.cn Telephone: +86-21-62572723-4304; +86-13636305607 Accepted: October 16,2012

Abstract

OBJECTIVE: To compare the effects of electrical stimulation of different acupoint combinations among postoperative bedridden elderly patients on hemorheology and deep venous blood flow velocity and investigate the role of electrical stimulation against deep vein thrombosis (DVT).

METHODS: From November 2010 to October 2011, a total of 160 elderly bedridden patients after major surgery were divided into the conventional care group, invigorating and promoting Qi group, blood-activating and damp-eliminating group, and acupoint-combination stimulation group. Whole

blood viscosity, plasma viscosity, D-dimer levels, lower limb skin temperature, lower limb circumference, and flow velocities of the external iliac vein, femoral vein, popliteal vein, and deep calf veins in all patients were documented and compared among the four groups.

RESULTS: Whole blood viscosity, plasma viscosity, D-dimer levels, and lower limb circumference were significantly reduced in the blood-activating and damp-eliminating group compared with the conventional care group (P<0.05) and were almost equal to those in the acupoint-combination stimulation group (P>0.05). Lower limb venous flow velocities were accelerated in the invigorating and promoting Qi group compared with the other groups, excluding the acupoint-combination stimulation group (P<0.05).

CONCLUSION: Hemorheological indices in postoperative bedridden elderly patients were improved after combined electrical stimulation at Yin-lingquan (SP 9) and Sanyinjiao (SP 6). Combined electrical stimulation at Zusanli (ST 36) and Ta-ichong (LR 3), on the other hand, accelerated lower limb venous flow.

© 2013 JTCM. All rights reserved.

Key words: Electric stimulation; Acupuncture point; Venous thrombosis; Blood flow velocity; Aged; Nursing care

INTRODUCTION

Deep vein thrombosis (DVT) is one of the most common surgical complications affecting the leg veins and

may lead to sequelae such as lower extremity thrombosis. In serious cases, it can cause fatal pulmonary embolism (PE), affecting patient prognosis and quality of life.1 During autopsy, 72% of people are found to have lower limb DVT. The most serious complication of DVT is PE, which is associated with 50 000 to 200 000 deaths each year.2 According to Virchow's triad,3 venous thrombosis occurs via three mechanisms: decreased blood flow rate, damage to the blood vessel wall, and an increased tendency of the blood to clot (hypercoagu-lability). Therefore, elderly bedridden patients who meet all criteria of Virchow's triad are prone to the development of DVT. Our previous studies reported the protective effect of combined electrical stimulation at Taichong (LR 3), Zusanli (ST 36), and Sanyinjiao (SP 6) on postoperative DVT prevention in patients with gastrointestinal malignancies. On this basis, we investigated the DVT prevention effect of different acupoint combinations to detect the functions of each acupoint and plan appropriate nursing care for each individual patient based on differentiation of symptoms and signs.

METHODS

Setting and design

Between January 2010 and October 2011, a total of 172 elderly bedridden patients who underwent major surgeries in the General Surgery, Gynecology, and Orthopedics Departments of our hospital were asked to participate in this study. After preoperative and postoperative health education and informed consent, 160 patients (93.02%) agreed to participate, with a refusal rate of 6.98%.

Patient inclusion criteria were as follows: 1) age of >60 years; 2) patients who underwent major surgery, including general surgeries, major gynecologic surgeries, limb fracture repair, etc; 3) operative duration of >2 h; 4) patients on postoperative bed rest who could not get out of bed; and 5) patients who signed the informed consent form. The study was performed in accordance with international ethical standards and was approved by the Ethics Committee of Putuo Hospital, Shanghai University of Traditional Chinese Medicine. Exclusion criteria were as follows: 1) inability to implement care measures in noncompliant patients, 2) patients who dropped out halfway for various reasons, 3) inability to implement interventions in patients with lower limb infection, and 4) inability to implement interventions in patients in critical condition.

Groups and methods

Following the random number table, all 160 patients were randomized into 4 groups as follows. Conventional care group: 40 patients (17 males and 23 females aged 60-85 years); 7 patients with gastric cancer, 6 with colon cancer, 5 with rectal cancer, 8 with femoral fractures, 8 with uterine tumors, and 6 with

ovarian tumors. From the first day after surgery, they accepted postoperative routine care, including observation, basic care, catheter care, prevention and care of complications, and health education. In addition, patients received help with raising the lower extremities and postoperative symptomatic care. Invigorating and promoting Qi group: 40 patients (15 males and 25 females aged 62-80 years); 5 patients with gastric cancer, 6 with colon cancer, 4 with rectal cancer, 10 with gallbladder cancer, 6 with femoral fractures, 5 with uterine tumors, and 4 with ovarian tumors. From the first day after surgery, they accepted postoperative routine care plus bilateral transcutaneous electrical stimulation at Taichong (LR 3) and Zusanli (ST 36) in two 20 min sessions per day (morning and afternoon) for 1 week.

Blood-activating and damp-eliminating group: 40 patients (12 males and 28 females aged 65-78 years); 6 patients with gastric cancer, 6 with colon cancer, 3 with rectal cancer, 3 with breast cancer, 5 with femoral fractures, 10 with uterine tumors, and 7 with ovarian tumors. From the first day after surgery, they accepted postoperative routine care plus bilateral transcutaneous electrical stimulation at Yinlingquan (SP 9) and Sanyinjiao (SP 6) in two 20 min sessions per day (morning and afternoon) for 1 week.

Acupoint-combination stimulation group: 40 patients (18 males and 22 females aged 63-87 years); 10 patients with gastric cancer, 8 with colon cancer, 6 with rectal cancer, 9 with femoral fractures, 4 with uterine tumors, and 3 with ovarian tumors. From the first day after surgery, they accepted postoperative routine care plus bilateral transcutaneous electrical stimulation of a combination of four acupoints: Taichong (LR 3), Zusanli (ST 36), Yinlingquan (SP 9), and Sanyinjiao (SP 6) in two 20-min sessions per day (morning and afternoon) for 1 week.

Equipment and application parameters

The G6805-II pulse acupuncture treatment instrument used in this study was produced by Shanghai Medical Device Technology Co., Ltd. (Shanghai, China). Stimulations with density-sparse waves (density wave of 100 Hz and sparse wave of 30 Hz), which had an intensity of 6 to 15 V, were administered with a slight vibration for 20 min on the corresponding parts of the body.

Main outcome measures

Severity of DVT and the chief complaint of the patients.

Color Doppler flow image: on the seventh preoperative and postoperative days, the diameter, blood flow velocity, and thrombosis were examined in the external iliac veins, femoral veins, popliteal veins, and deep calf veins using an ACUSON Sequoia 512 (Siemens, Is-saquah, USA).

Determination of coagulative function: D-dimer levels

on the seventh preoperative and postoperative days were determined.

Changes in hemorheology: blood viscosity (including whole blood viscosity and plasma viscosity) on the seventh preoperative and postoperative days was determined.

Other indicators, including patient age, disease, hospitalization time, and surgical procedures, were documented.

Statistical methods

All data were analyzed with the statistical software PEMS3.1 (West China School of public health, Sichuan University, Chengdu, China) using the two-sample mean t test. A P value of <0.05 was considered to be statistically significant.

RESULTS

Two patients in the conventional care group were diagnosed with calf DVT with chief complaints of leg swelling and pain. Patients in the other three groups developed neither DVT nor leg swelling and pain. The diameter and blood flow of the external iliac vein in the four groups are shown in Table 1. Significantly accelerated flow rates in the bilateral external iliac veins were observed in the invigorating and promoting Qi group (P<0.05). Similar results were seen in the acu-point-combination stimulation group (P>0.05). Differences in diameter changes of the vessels, on the other hand, were not significant (P>0.05). The diameter and blood flow of the femoral vein in the four groups are shown in Table 2. The same out-

comes were found in the femoral veins. Accelerated flow rates in the bilateral femoral veins. were observed in the invigorating and promoting Qi group (P<0.05). Similar results were seen in the acupoint-combination stimulation group (P>0.05). Differences in diameter changes of the vessels, on the other hand, was not significant (P>0.05).

The diameter and blood flow of the bilateral popliteal veins in the four groups are shown in Table 3. The same outcomes were found in the popliteal veins. Accelerated flow rates in the bilateral popliteal veins were observed in the invigorating and promoting Qi group (P<0.05). Similar results were seen in the acu-point-combination stimulation group (P>0.05). Differences in diameter changes of the vessels, on the other hand, were not significant (P>0.05). The diameter and blood flow of the bilateral deep calf veins in the four groups are shown in Table 4. The same outcomes were found in the deep calf veins. Accelerated flow rates in the bilateral deep calf veins were observed in the invigorating and promoting Qi group (P<0.05). Similar results were seen in the acu-point-combination stimulation group (P>0.05). Differences in diameter changes of the vessels, on the other hand, were not significant (P>0.05). Comparisons of the postoperative whole blood viscosity and plasma viscosity in the four groups are shown in Table 5. As seen in Table 5, the postoperative whole blood viscosity and plasma viscosity in the conventional care group were significantly higher than those in the other three groups, while differences among the other three groups were not statistically significant. Postoperative D-dimer levels in the conventional care

|Table 1 Comparison of diameter and blood flow of the external iliac veins in four groups (x± s)

Group n Diameter of LEIV (mm) Diameter of REIV (mm) Flow rate of LEIV (cm/s) Flow rate of REIV (cm/s)

A 40 3.23±0.57 3.24±0.60 8.51±0.72 7.81±1.22

B 40 4.19±3.33 3.27±3.62 10.54±7.67 9.15±6.24

C 40 3.59±2.09 3.53±1.86 9.00±5.28 8.17±4.95

D 40 3.33±2.38 3.43±2.43 10.15±4.35 9.37±4.35

P value >0.05 >0.05 A vs B P<0.05 A vs B P<0.05

BvsD P>0.05 BvsD P>0.05

Notes: A: conventional care group; B: "Invigorating Qi and promoting Qi" group; group; D: Acupoint-combination stimulation group. LEIV: left external iliac vein; C: "Blood-activating and Damp REIV: right external iliac vein. ness-eliminating"

Table 2 Comparison of diameter and blood flow of the external iliac veins in four groups (x ± s) |

Group n Diameter of LFV (mm) Diameter of RFV (mm) Flow rate of LFV (cm/s) Flow rate of RFV (cm/s)

A 40 5.43±1.35 5.31±1.36 14.73±2.42 13.85±2.48

B 40 8.39±2.58 8.46±2.70 20.67±6.44 19.26±5.96

C 40 7.49±2.69 7.49±2.81 18.36±5.11 17.08±4.59

D 40 5.53±0.17 5.41±0.20 19.67±1.44 19.30±0.61

P value >0.05 >0.05 A vs B P<0.05 A vs B P<0.05

B vs D P>0.05 B vs D P>0.05

Notes: A: conventional care group; B: "Invigorating Qi and promoting Qi" group; C: "Blood-activating and Dampness-eliminating" group; D: Acupoint-combination stimulation group. LFV: left femoral vein; RFV: right femoral vein.

group were significantly elevated compared with those in the other three groups; comparisons between the blood-activating and damp-eliminating and acu-point-combination stimulation groups showed no statistically significant differences.

Comparisons of postoperative skin temperature and circumference of the left lower extremity in the four groups are shown in Table 6. As seen in Table 6, differences in the postoperative skin temperature of the left lower extremity among the four groups were not statistically significant. A larger postoperative circumference of the left lower extremity was seen in the conventional care group than in the other three groups. No statistically significant differences were observed between the blood-activating and damp-eliminating and acu-point-combination stimulation groups. Comparisons of postoperative skin temperature and circumference of the right lower extremity in the four groups are shown in Table 7. As seen in Table 7, differences in the postoperative skin temperature and circumference of the right lower extremity among the

four groups showed no statistical significance.

DISCUSSION

Pathogenesis of DVT

DVT is an extremely common medical problem that mainly affects the large veins in the lower limb. It occurs either in isolation or as a complication of other diseases or procedures, especially surgical operations.4 Its symptoms include increased skin temperature, swelling, and pain. Without treatment, a DVT can break off and travel to the lung, resulting in pulmonary embolism and death.

The most serious complication of DVT is PE, which is associated with 50 000 to 200 000 deaths each year.5 In particular, postoperative patients with a malignancy have a remarkably higher risk. Colwell reported a 40% to 60% incidence of DVT in patients after orthopedic surgery when preventive measures were not imple-mented.6

able 3 Comparison of diameter and blood flow of the popliteal veins in four groups (x±s)

Diameter of LPV _(mm)_

Diameter of RPV _(mm)_

Flow rate of LPV _(cm/s)_

Flow rate of RPV _(cm/s)_

6.81±0.44

6.91±0.57

12.14±2.89

11.58±3.23

B 40 6.53±0.28 6.68±0.27 15.53±2.14 14.11±2.49

C 40 6.75±0.30 6.89±0.26 12.35±1.03 12.00±1.24

D 40 6.17±0.43 6.63±0.19 15.45±1.75 14.16±1.00

P value >0.05 >0.05 AvsB P<0.05 AvsB P<0.05

B vs D P>0.05 B vs D P>0.05

Notes: A: conventional care group; B: "Invigorating Qi and promoting Qi" group; C: "Blood-activating and Dampness-eliminating" group; D: Acupoint-combination stimulation group. LPV: left popliteal vein; RPV: right popliteal vein.

|Table 4 Comparison of diameter and blood flow of the calf deep veins in four groups (x±s) |

Group Diameter of LCDV Diameter of RCDV Flow rate of LCDV Flow rate of RCDV

n (mm) (mm) (cm/s) (cm/s)

A 40 2.51±0.36 2.51±0.23 9.09±1.87 8.34±1.47

B 40 2.59±0.16 2.63±0.11 11.16±2.02 10.06±1.71

C 40 2.54±0.16 2.60±0.11 9.19±1.83 8.30±1.72

D 40 4.94±0.98 4.77±0.87 11.27±1.69 11.40±1.71

P value >0.05 >0.05 AvsB P<0.05 AvsB P<0.05

B vs D P>0.05 B vs D P>0.05

Notes: A: conventional care group; B: "Invigorating Qi and promoting Qi" group; C: "Blood-activating and Dampness-eliminating" group; D: Acupoint-combination stimulation group. LCDV: left calf deep vein; RCDV: right calf deep vein.

¡Table 5 Comparison of postoperative whole blood viscosity and plasma viscosity in four groups (x±s) |

Group n Whole blood viscosity (mpas) Plasma viscosity (mpas) D-dimer

A 40 19.160±2.550 1.460±0.023 0.940±0.082

B 40 17.600±3.400 1.330±0.020 0.440±0.078

C 40 17.860±2.280 1.340±0.015 0.300±0.036

D 40 17.450±2.310 1.330±0.039 0.210±0.021

P value - Avs B, Avs D, P<0.05 A vs B AvsC,Avs D, P<0.05 AvsB, A vs C, A vs D, P<0.05

Notes: A: conventional care group; B: "Invigorating Qi and promoting Qi" group; C: "Blood-activating and Dampness-eliminating" group; D: Acupoint-combination stimulation group.

¡Table 6 Comparison of postoperative skin temperature and circumference of the left lower extremity in four groups (t, x± s) j

Group n LLE mean skin Temp. (Morning) LLE mean skin Temp. LLE (Afternoon) mean circumference (Morning) LLE mean circumference (Afternoon)

A 40 35.6±1.2 35.6±1.2 39.9±4.9 39.9±4.9

B 40 36.3±0.9 36.3±1.0 38.7±8.0 38.7±8.0

C 40 36.2±0.8 36.2±0.9 35.9±2.8 35.9±2.8

D 40 35.6±0.7 35.8±0.7 36.6±9.6 36.6±9.5

P value - >0.05 >0.05 AvsC, P<0.05 AvsC, P <0.05

Notes: A: conventional care group; B: "Invigorating Qi and promoting Qi" group; group; D: Acupoint-combination stimulation group. LLE: left lower extremity. C: "Blood-activating and Dampness-eliminating"

|Table 7 Comparison of postoperative skin temperature and circumference of the right lower extremity in four groups (t, x± s)

Group n RLE mean skin Temp. (Morning) RLE mean skin Temp. RLE mean circumference (Afternoon) (Morning) RLE mean circumference (Afternoon)

A 40 36.8±1.0 36.6±0.9 36.1±1.4 36.1±1.0

B 40 36.5±1.0 36.0±0.9 36.1±1.1 36.1±1.3

C 40 35.9±0.9 36.2±0.7 35.6±0.7 35.7±0.9

D 40 35.5±0.9 35.3±0.8 35.6±1.4 35.6±1.4

P value - >0.05 >0.05 >0.05 >0.05

Notes: A: conventional care group; B: "Invigorating Qi and promoting group; D: Acupoint-combination stimulation group. RLE: right lower the vessel wall, and 3) hypercoagulability were the major factors responsible for the development of DVT.7 Lower limb muscle paralysis and peripheral vein dilation due to surgery, trauma, and anesthesia in postoperative elderly patients, who have a limited tolerance for surgery, were almost completely consistent with Vir-chow's triad. In addition, loss of contractile function and long-term bed rest during anesthesia and surgical operations further hinder lower limb muscle contraction and venous flow, leading to blood stasis.8 Anesthesia-induced venous smooth muscle relaxation stretches endothelial cells, causing exposure of collagen fibers, platelet aggregation, and activation of the extrinsic coagulation system, thus predisposing patients to venous thrombosis.9 Anxiety and stress during surgery, on the other hand, may increase blood viscosity in patients.

Prophylaxis of DVT

Previous reports have demonstrated that DVT is a clinical problem that requires active prevention.10 Multicenter trials have proved that preventive measures are effective in reducing the mortality of DVT, incidence of PE, and mortality of PE by at least 60%.11,12 Inappropriate prevention contributes to DVT development in the majority of patients after discharge.13 There is still no single or compound pharmacological therapy available to avoid the problematic postoperative DVT associated with artificial joint replacement. However, compound drug therapy plus mechanical prevention is of great benefit to the patient. Some useful preventive measures include:

Basic prevention: sufficient hydration, a high-protein

Qi" group; C: "Blood-activating and Dampness-eliminating" extremity; Temp: temperture.

ing prohibition are recommended. Underlying anemia, hypertension, and diabetes should be treated. Careful dissection during surgical operations is helpful in lowering the risk of endothelial damage.14 Functional exercise: patients should be guided to practice preoperative isometric flexion exercises of the ankle, knee, and quadriceps. Early postoperative ambulation is recommended for the promotion of lower limb blood circulation and prevention of DVT. Mechanical prevention: standard-length stockings or intermittent pneumatic compression pumps are suggested to improve blood stasis.

Drug prevention: anticoagulants such as warfarin and low-molecular-weight heparin can be administered to prevent platelet aggregation, and low-molecular-weight dextran can be used prophylactically to facilitate micro-circulation.15

Thrombolysis and anticoagulation are the mainstay treatments of DVT. Intravenous urokinase is given to patients with DVT for a duration of no more than 3 days.16 Continuous intravenous infusion of low-molecular-weight heparin is given to prevent thrombosis. Low-molecular-weight dextran and compound Dansh-en are used to prevent platelet aggregation, expand blood volume, and improve microcirculation. Limb hot packs and repeated vein puncturing are prohibited.17 Based on the pathogenesis of DVT, our study showed that combined electrical stimulation at Taichong (LR 3) and Zusanli (ST 36) or at Yinlingquan (SP 9) and Sanyinjiao (SP 6) was effective in preventing postoperative DVT in elderly patients with gastrointestinal ma-

lignancies.

Low-frequency pulse stimulations prophylactically accelerate the blood flow of the lower limbs and decrease blood viscosity.18 To further identify different functions of distinct acupoints, we randomized the patients into two groups according to the function of acupuncture points as follows.

Patients in one group received electrical stimulation at Taichong (LR 3) and Zusanli (ST 36), which had the effect of invigorating and promoting Qi. Patients in the other groups received electrical stimulation at Yin-lingquan (SP 9) and Sanyinjiao (SP 6), which was blood-activating and damp-eliminating. Diameters and blood flow velocity of the lower limb deep veins were measured and compared with the conventional care and acupoint-combination stimulation groups to reveal the optimized combination of acupoints.

Different effects of electrical stimulation at distinct acupoints

Zusanli (ST 36) is one of the main acupuncture points of the Stomach Meridian of Foot Yangming. It is a main point for strengthening the body and mind. Traditional Chinese Medicine (TCM) holds that massaging Zusanli (ST 36) can adjust immunity, enhance disease-resistance, regulate the stomach and spleen, tonify the middle jiao and antipathogenic Qi, clear and activate the meridians and collaterals, dispel wind and defuse eczema, strengthen body resistance, and eliminate pathogenic Qi.

Taichong (LR 3) is located on the instep of the foot, in the depression of the posterior end of the first interosseous metatarsal space. It belongs to the Liver Meridian of Foot Jueyin, which lowers blood pressure and promotes liver function and circulation. Needling Ta-ichong (LR 3) reportedly dilates local small veins, increases blood flow velocity, and releases headache,18 thus activating blood circulation and dredging the me-ridians.19

Electrical stimulation at Taichong (LR 3) and Zusanli (ST 36), as the results of this study demonstrated, promotes the Qi circulation. In addition, it markedly accelerates the blood flow of the external iliac veins, femoral veins, popliteal veins, and deep calf veins, thus preventing DVT with an effect equal to that of the combined electrical stimulation at the four acupoints. Electrical stimulation at Yinlingquan (SP 9) and Sanyinjiao (SP 6), on the other hand, has a limited effect on lower limb venous flow.

As mentioned in the above results, blood viscosity and D-dimer levels were reduced in all three groups treated by electrical stimulation. Based on the final D-dimer levels, it can be seen that electrical stimulation at Yin-lingquan (SP 9) and Sanyinjiao (SP 6) has no difference in effect compared with electrical stimulation at all four acupoints. Low-frequency pulse stimulation at Yinlingquan (SP 9) and Sanyinjiao (SP 6) not only improves local blood circulation, but also strengthens the

anticoagulant mechanism.20,21

In TCM, the spleen is the source of blood and Qi and the root of acquired constitution. Consequently, electrical stimulation dilates the venules and decreases fibrinogen and fibrin degradation product levels.22 Electrical stimulation at the two acupoints, as well as that at all four acupoints, functions to nourish the spleen and promote Qi and blood circulation, thus preventing DVT.

Electrical stimulation at Yinlingquan (SP 9) and Sany-injiao (SP 6), and that at all four acupoints, reduced the lower limb circumference, and this result was statistically significant compared with the other two groups. In terms of improving circulation, there was no significant difference in the results of the two groups. According to TCM, electrical stimulation at Yinlingquan (SP 9) and Sanyinjiao (SP 6) dissolves damp and activates circulation, thus preventing DVT. The fibrinolytic system prevents thrombosis and maintains blood flow in the physiological condition. It is activated during thrombosis and produces plasmin, which contributes to degradation of cross-linked fibrin and results in various fragments; one of the simplest degradation products is the plasma D-dimer. Elevated D-dimer levels reflect activation of both the coagulation system and the fibrinolytic system. The D-dimer level measured by immunoassay is one of the most trustworthy indicators facilitating early diagnosis and predicting the prognosis of thromboembolic diseases. It is associated with disease severity and can help physicians tailor an appropriate treatment. The D-dimer level is also ideal for monitoring the thrombus formation process and the effect of anticoagulant and thrombolytic treatment with high sensitivity and specificity.23 Being simple, noninvasive, and economic, the D-dimer level has been widely used for DVT screening by clini-

cians.

Cautions during implementation of electronic stimulation

Nursing staff members should ensure accurate position and intensity and monitor the patient response, such as that shown by local skin changes, during implementation of electrical acupoint stimulation. It is essential to prevent complications caused by electrical stimulation, such as skin redness and pain.

In the present study, the effect of electrical stimulation at different acupoints on preventing DVT was investigated. The results showed that combined stimulation at Yinlingquan (SP 9) and Sanyinjiao (SP 6) or at Taichong (LR 3) and Zusanli (ST 36) had an effect equal to that of combined stimulation at all four acupoints in terms of activating circulation and accelerating lower limb blood flow. Further investigations on the functions of distinct acupoints will lead to a better understanding of implementation of appropriate electrical stimulation for each individual patient. This may be a potentially safe and effective DVT-pre-

vention method that reduces nurses' work intensity and patients' expenses. This method, which integrates TCM and Western Medicine, may promote other valuable research on DVT prevention in postoperative elderly patients.

REFERENCES

1 Cai LL, Xu Y. Progress of prophylaxis and nursing care with deep venous thrombosis. Jie Fang Jun Hu Li Za Zhi 2003; 20(11): 39-40.

2 Aquila AM. Deep venous-thrombosis. J Cardiovasc Nurs 2001; 15(4): 25-44.

3 Brian Coghlan, Leon P Bignold. Virchow's Eulogies: Rudolf Virchow in Tribute to His Fellow Scientists. Birkhaus-er Verlag AG 2008; 234-235.

4 Ding CF. Prevention and nursing in elderly patients after gynecologic operation complicated with deep venous thrombosis. Neimenggu Yi Xue Za Zhi 2011; 43(8): 999-1000.

5 Hou LL, Yao LW, Niu QM, et al. Preventive effect of electrical acupoint stimulation on lower limb thrombosis: a prospective study of elderly patients after malignant gastrointestinal tumor surgery. Cancer Nurs 2013; 36(2): 139144.

6 Colwell CW Rationale for thromboprophylaxis in lower joint arthroplasty. AM J Orthop 2007; 36(9): 11-13.

7 Cao H, Li W, Xie XR, et al. Overview of the orthopedic treatment of deep vein thrombosis. Yi Xue Zong Shu 2008; 14(2): 275-278.

8 Liang HH, Duan XW. Prevention and care of inguinal hernia in elderly postoperative deep vein thrombosis. Zhong Hua Shan He Fu Bi Wai Ke Za Zhi 2011; 5(2): 241-242.

9 Zhang JW. Progress of prevention and treatment with pulmonary embolism. Zhong Guo Shi Yong Wai Ke Za Zhi 2005; 25(4): 246-248.

10 National Institute of Health and Clinical Excellence. Reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients undergoing surgery. NICE clinical guideline No 46: l-160. Available from URL: http://www.nice.org.uk/CG046. Accessed March 31, 2008.

11 Callaghan JJ, Dorr LD, Engh GA, et a1. Prophylaxis for thromboembolitic disease: recommendations from the American College of Chest Physicians-are they ap-

propriate for orthopaedic surgery. J Arthroplasty 2005; 20(3): 273.

12 Turpie AG, Bauer KA, Caprini JA, et a1. Fondaparinux combined with intermittent pneumatic compression vs. intermittent pneumatic compression alone for prevention of venous thromboembolism after abdominal surgery: a randomized, double-blind comparison. J Thromb Haemost 2007; 5(9): 1854.

13 Borah B, McDonald H, Henk J, et a1. Alignment to AC-CP prophylaxis guidelines and VTE outcomes in THR and TKRpatients. Blood 2008; 112(1): 70.

14 Qiu GX, Dai R, Yang, QM, et al. Experts suggestion of deep vein thrombosis prevention after major orthopedic surgery. Zhong Guo Yi Shi Za Zhi 2006; 34(2): 31-32.

15 Herring MD. 3rd. In: Herring MDJohn A. Tachdjian' s Pediatric Orthopaedics. Philadelphin: WB Saunders Company, 2002: 2139.

16 Hai LT. 22 Cases Clinical Observation of acute DVT with orthopedic in thrombolytic therapy. Zhong Hua Xian Dai Nei Ke Xue Za Zhi 2008; 5(8): 742-743.

17 You PH. The prevention of deep venous thrombosis after orthopedic surgery. Zhong Guo Shi Yong Yi Yao 2010; 5 (26): 70-71.

18 Hou LL, Xu L, Yao LW. The function of electricity stimulates at acupuncture points against the postoperative lower deep venous thrombosis in the old-age malignant tumor of the stomach and intestine. Jie Fang Jun Hu Li Za Zhi 2008; 25(128): 8-11.

19 Hou LL. Different acupoints care for the prevention of elderly postoperative ambulatory patients with thrombosis hemorheology. Zhong Guo Shi Yong Hu Li Za Zhi 2011; 7(29): 56-57.

20 Yan P, Ji LX. Acupoint group of gastric mucosal injury. Shanghai Zhen Jiu Za Zhi 2001; 20(4): 44.

21 Zhao H, Zhang WB. Affection of microcirculation blood flow in meridians. Wei Xun Huan Za Zhi 1998; 8(1): 41.

22 Zhang BG. Treatment and thinking of deep venous thrombosis. Zhong Hua Wai Ke Za Zhi 2001; 39: 823-824.

23 Di Nisio M, Squizzato A, Rutjes AW, et al. Diagnostic accuracy of D-dimer test for exclusion of venous thrombo-embolism: A systematic review. J Thromb Haemost 2007; 5(2): 296.

24 Righini M, Perrier A, De Moerloose P, et al. D-Dimer for venous thromboembolism diagnosis 20 years later. Thromb Haemost 2008; 6(7): 1059.