Biomedical therapeutic compression textiles: Physical-mechanical property analysis to precise pressure management

Biomedical therapeutic compression textiles (TCTs) have been extensively applied in the prevention and treatment of chronic venous insufficiency of lower extremities. An efficiency and operable development strategy to achieve the morphologic control and pressure fitness of TCTs needs to be proposed to improve the medical precision and patient adherence. Therefore, the present study qualitatively explored the influencing mechanisms of each knitting variable on physical-mechanical properties and pressure behaviors of TCTs. Then constructed the quantitative models to digitalize the knitting variables for determination of yarn-machinery setting design values. The results revealed that the feeding velocity of elastic inlay yarn materials and loop size settings impacted the pressure values owing to the diversities of fabric dimensions and mechanical tensile properties, respectively. Simultaneously, the derivation ratios of proposed circumferential and pressure models evaluated by experimental validated trials were approximately 1.1% and 10.8%, respectively. This study provided the fundamental references for the design, manufacturing, and property controlling of compression textiles to improve the biomedical therapeutic effectiveness for targeted users.

Sensitivity of the properties of the graduated compression stocking and soft tissues on the lower limb-stocking interfacial pressure using the orthogonal simulation test

Graduated compression stocking (GCS) plays an important role in the treatment of venous disease in the lower limb. However, the effect of the variation in the mechanical properties of the GCS and the soft tissues on the treatment of the venous disease in the lower limb remains unclear. The aim of the present study was to investigate the influence of the material properties of the GCS and soft tissues on the lower limb-stocking interfacial pressure using the orthogonal simulation test. A three-dimensional finite element (FE) model of the lower limb was established using the MRI dataset of a 40-year-old volunteer. The bones, the skin, the veins and the skeletal muscles were reconstructed in the FE model. The FE model of the GCS was generated using the information provided by the manufacturer. Then the parameter sensitivity analysis was performed using a two-step orthogonal simulation test. The first-step orthogonal test showed that the variation in the Young's modulus in the wale direction of the GCS induced a change of 0.37 mmHg in the lower limb-stocking interfacial pressure in the ankle section. The second-step orthogonal test showed that the variations in the Young's modulus in the wale direction of the GCS in the knee section induced the changes of 0.05 mmHg, 0.15 mmHg and 0.60 mmHg in the interfacial pressure in the ankle, the calf and the knee, respectively. In conclusion, the Young's modulus in the wale direction of the GCS and the Poisson's ratio of the GCS are the parameters significantly influencing the lower limb-stocking interfacial pressure. The interfacial pressure in the ankle is not sensitive to the Young's modulus in the wale direction of the GCS in the knee section. However, the interfacial pressures in the calf and knee are sensitive to the Young's modulus in the wale direction of the GCS in the knee section. These data provide important information for the design of GCS.

Graduated compression stockings in prevention of venous thromboembolism among acutely ill medical patients aged over 75 years: a French national survey

Background: The thromboprophylactic efficacy of graduated compression stockings (GCS) has not yet been demonstrated in acutely ill medical patients, and guidelines vary considerably. Older acutely ill medical patients appear to constitute a distinctive population presenting high risks of both thrombosis and bleeding.

Objective: To evaluate the practices and beliefs of a panel of French geriatricians regarding GCS management in acutely ill medical patients aged over 75 years.

Methods: A survey was designed to study French geriatric practice concerning GCS use for thromboprophylaxis.

Results: A total of 111 geriatricians answered the questionnaire. Among the responders, 46% declared frequent or very frequent prescription of GCS for preventing venous thromboembolism (VTE) in acutely ill, hospitalized medical patients, 54% declaring that they frequently re-evaluated GCS prescription during the patient’s hospitalization. The main reason reported for discontinuing GCS use was patient request. Regarding complications of GCS, 87% of responders declared having already noted adverse effects with the use of GCS, although 80% estimated the risk of complications to be low or very low. In the context considered, the efficacy of wearing GCS was believed to be high or very high for 73% of responders. GCS prescription was judged to be in accordance with evidence-based medicine for 69%.

Conclusion: There is a gap between the frequent use of GCS to prevent VTE in older patients presenting an acute medical illness and the availability of data concerning their efficacy, safety, and management by nurses. Prospective trials including clinical and cost effectiveness are needed.

Semiautomatic intermittent pneumatic compression device applied to deep vein thrombosis in major orthopedic surgery

Objective

To investigate the effect of additional semiautomatic intermittent pneumatic compression device (IPCD) in the prevention of deep vein thrombosis (DVT) of lower extremity in these patients undergoing major orthopedic surgery, when compared with the conventional graduated compression stockings alone.

Methods

The data of 112 patients undergoing major orthopedic surgery were retrospectively analyzed. 51 patients who ever received IPCD and graduated compression stockings during major orthopedic surgery were taken as the experimental group, and 61 patients who only received the conventional graduated compression stockings during surgery were taken as the observation group. The Doppler sonography was utilized to detect the presence of DVT and pulmonary embolism pre- and postoperatively. Besides, the mean and peak velocity of blood flow in femoral vein were recorded before and after surgery. And then, the comparisons between the two groups were made, respectively.

Results

When compared with the conventional graduated compression stockings alone, the intraoperative application of IPCD and stockings contributed the significant reduction of DVT (3.92%, 2/51 versus 9.84%, 6/61, X² = 5.632, P = 0.034). In terms of the mean and peak velocity of blood flow in femoral vein, the postoperative difference was higher in the observation group than those in the control group (149.56 ± 26.35 versus 130.15 ± 22.56 mm/s, P < 0.05). With respect to perioperative blood loss, the difference between the two groups was statistically significant (800.5 ± 320.7 versus 950.1 ± 305.9 ml, P = 0.031).

Conclusions

Intraoperative application of IPCD could promote blood circulation of lower limbs, and significantly decrease the incidence of potentially fatal DVT in patients undergoing major orthopedic surgery, when compared with the conventional graduated compression stockings.

Patients' perceptions and experiences of the prevention of hospital-acquired thrombosis: a qualitative study

OBJECTIVE

To examine patients' understanding of hospital-associated thrombosis, and their experiences of thromboprophylaxis.

DESIGN

Qualitative study using semi-structured interviews with 31 patients requiring venous thromboembolism (VTE) prophylaxis following a recent hospital admission. Interviews were audio-recorded, transcribed verbatim and analysed thematically using framework analysis.

SETTING

4 hospitals in Birmingham and Oxford.

RESULTS

All the participants received thromboprophylaxis following surgical procedures. Participants were aware of a risk of blood clots; however, they lacked a good understanding of VTE and its components. Experiences of VTE prophylaxis were characterised with good adherence to heparin injections and poor adherence to elastic compression stockings, largely due to perceived lack of clarity in guidance from health professionals. Participants had limited knowledge of the signs and symptoms of VTE and would value improved education on VTE.

CONCLUSIONS

Findings suggest that patient education is often inadequate and impacts negatively on patients' involvement in VTE prevention. An enhanced patient education programme incorporating a consistent message on the appropriate use of elastic compression stockings and description of VTE symptoms is likely to optimise the effectiveness of the prevention of hospital-associated thrombosis. Physicians may use the results of this study to improve individual patient education.

The Effectiveness of a Risk Stratification Protocol for Thromboembolism Prophylaxis After Hip and Knee Arthroplasty

BACKGROUND

This study's purpose was to present our institution's experience with the use of a risk stratification protocol for venous thromboembolism (VTE) prophylaxis in joint arthroplasty in which "routine" risk patients receive a mobile compression device in conjunction with aspirin and "high"-risk patients receive warfarin for thromboprophylaxis.

METHODS

This was a prospective study of patients undergoing primary or revision knee or hip arthroplasty. Exclusion criteria were patients with a current deep vein thrombosis, history of pulmonary embolism, chronic warfarin therapy, planned multiple surgeries, and prolonged postoperative immobilization. Patients were stratified as either routine or high risk. Routine risk patients received mobile compression devices for 10 days and aspirin twice daily for 6 weeks, whereas high-risk patients received warfarin for 4 weeks and compression stockings for 6 weeks.

RESULTS

A total of 3143 total joint arthroplasties were enrolled (2222, 70.7% "routine"; 921, 29.3% "high risk"). The rate of symptomatic VTE within 6 weeks postoperatively was 0.7% (95% CI 0.3%-1.0%) in the standard vs 0.5% (95% CI 0.01%-1.0%) in the high-risk cohort (P = .67), and within 6 months postoperatively was 0.6% (95% CI 0.3%-1.0%) in the standard vs 1.1% (95% CI 0.4%-1.8%) in the high-risk cohort (P = .23). The rate of major bleeding events was significantly lower in the routine (0.4%; 95% CI 0.1%-0.6%) vs high-risk (2.0%; 95% CI 1.0%-3.0%; P < .001) cohort.

CONCLUSIONS

This study demonstrates that use of a risk stratification protocol allowed the avoidance of more aggressive anticoagulation in 70% of patients while achieving a low overall incidence of symptomatic VTE.