Multilayer Compression Research Articles

Impact of multilayered compression bandages on sub-bandage interface pressure: a model

Multi-component medical compression bandages are widely used to treat venous leg ulcers. The sub-bandage interface pressures induced by individual components of the multi-component compression bandage systems are not always simply additive. Current models to explain compression bandage performance do not take account of the increase in leg circumference when each bandage is applied, and this may account for the difference between predicted and actual pressures. To calculate the interface pressure when a multi-component compression bandage system is applied to a leg. Use thick wall cylinder theory to estimate the sub-bandage pressure over the leg when a multi-component compression bandage is applied to a leg. A mathematical model was developed based on thick cylinder theory to include bandage thickness in the calculation of the interface pressure in multi-component compression systems. In multi-component compression systems, the interface pressure corresponds to the sum of the pressures applied by individual bandage layers. However, the change in the limb diameter caused by additional bandage layers should be considered in the calculation. Adding the interface pressure produced by single components without considering the bandage thickness will result in an overestimate of the overall interface pressure produced by the multi-component compression systems. At the ankle (circumference 25 cm) this error can be 19.2% or even more in the case of four components bandaging systems. Bandage thickness should be considered when calculating the pressure applied using multi-component compression systems.

In vivoeffect of sustained-release silver sulphadiazine foam on bioburden and wound closure in infected venous leg ulcers

To determine the in vivo effect of a sustained-release silver sulphadiazine powder foam dressing on the bacterial burden of venous leg ulcers (VLUs), with a view to correlating the wound closure rate with the degree of bioburden and to assess other markers of its progression towards healing. Patients attending a tertiary care wound practice were screened for a VLU bacterial count of >105 colony forming units (cfu/g) per gram of tissue. Patients were treated with the above topical dressing plus multilayer compression bandaging for 12 weeks. Quantitative cultures were taken at weeks 0, 2, 4 and 8. Wounds were assessed at each weekly visit using photography and planimetry. Twenty-four of the 33 screened patients met the inclusion criteria. The average baseline wound size was 12.3 cm². At week 8, the bioburden had reduced to < 105 cfu/g in 54.2% of patients, with 41.7% achieving this reduction by week 2. At week 8, the median reduction was 0.7 log¹⁰ (p < 0.001). The median percentage reductions in bioburden were 50.5%, 56.8% and 80.4% at weeks 2, 4 and 8 respectively. Over the study period, 79.2% of the patients had > 75% wound area reduction and 45.8% achieved ulcer closure in a median of 80.5 days. Although the wound size and bacterial counts reduced significantly, there was no statistical correlation between the two. Nevertheless, the in vivo data show that this active antimicrobial dressing was associated with a very high healing rate in these hard-to-heal wounds.

The Need for an Intersociety Consensus Guideline for Venous Ulcer

Due to their recurrence and prolonged healing time, venous ulcers (VU) consume considerable resources in healthcare systems–up to 1% of healthcare budgets in some industrialized countries. Best practice guidelines (GLs) incorporate evidence-based diagnostic and therapeutic recommendations in a cost-effective manner and have been associated with improved and effective outcomes for many diseases (eg, deep vein thrombosis/pulmonary embolism). In order to develop a more universal GL we determined whether there are common elements in GLs for venous ulcers and their evidentiary strength. A systematic analysis of GLs for venous ulcers that were identified through http://clinicaltrials.gov, a government-sponsored Web site, and from experts outside the US. Ten of 12 GL on venous ulcers (seven from North America and five from Europe) were evidence-based, with the majority using the GRADE method. Only two had been developed or updated within the last 3 years. Venous duplex and ankle-brachial index were recommended in all. Debridement was suggested in two, while simple nonadherent wound dressings were favored in nine, and hydrocolloid in two. Only one GL discussed a range of dressing options, dependent on the condition of the venous ulcers. High-pressure multi-layer compression bandages were favored in 10. Only two focused on the importance of improving ankle joint mobility. While there are numerous evidence-based GLs for venous ulcers, the majority may lag recent developments in the field. There is agreement on two elements–dressings and compression, among the various GLs, which should facilitate the development of a consensus GL, similar to that for deep vein thrombosis/pulmonary embolism. To improve patient care and reduce wasted resources, it is imperative for specialty societies to join together and develop this consensus document.

Effect of elasticity on subbandage pressure of three layer tubular compression bandages in healthy volunteers: a RCT

To estimate the difference between mean interface sub-bandage pressures of two multilayer compression bandage systems in healthy volunteers when supine, standing, exercising and during recovery. Inelastic and elastic compression bandages were randomised to opposite limbs of each participant. Sub-bandage interface pressures for both bandages were compared within person. Participants and study staff were aware of the treatment. A pressure transducer measured sub-bandage pressures on the medial aspect of the lower leg, at the transition of the gastrocnemius muscle into the Achilles tendon (B1). The difference in interface pressure for the two different compression bandages was measured at level B1 during supine resting, standing, exercise and recovery. We defined the pressure difference between active standing and lying as a measure of stiffness, and amplitude as the range of pressures during plantar flexion while standing. The two bandage systems (inelastic and elastic) were applied from the base of the toes to just below knee and remained in place for the duration of the experiment. Elastic bandage consisted of three layers of graduated tubular bandage (83% cotton, 9% Lycra, 8% polyamide). Inelastic or short-stretch bandage consisted of 100% cotton crepe bandage. Interface sub-bandage pressures varied during different activities, but the mean difference in interface pressures between inelastic and elastic bandages was consistently at least 13 mm Hg. Stiffness was 7.3 mm Hg higher in the inelastic group (95% CI 5.1-9.5). The estimated difference in amplitude of sub-bandage pressure between the bandages during exercise was 15.5 mm Hg (95% CI 12.2-18.9). We found in vivo interface sub-bandage pressures varied with the type of bandage and activity phase. Inelastic bandages resulted in an increased mean interface sub-bandage pressure when resting and recovering, which was further increased when standing or exercising. Bandage stiffness and amplitude were also greater for inelastic compared with elastic bandages. None.

Pharmacological treatment in patients with C4, C5 and C6 venous disease

A range of surgical, endovenous, physical and medical treatments are available for patients with chronic venous disease. The aim of this review was to evaluate the evidence for pharmacological agents used for the treatment of chronic venous disease. A literature search was performed using Pubmed, Embase, Cochrane and Google Scholar databases. The initial search terms 'varicose vein', 'venous ulcer', 'venous disease' and 'lipodermatosclerosis' were used to identify relevant clinical studies of pharmacotherapy in patients with chronic venous disease (C4-C6). A huge range of naturally occurring and synthetic drugs have been studied in patients with chronic venous disease. For patients with C4 venous disease, micronized purified flavonoid fraction (MPFF), oxerutin, rutosides and calcium dobesilate may reduce venous symptoms and oedema. MPFF and pentoxifylline have been shown to improve venous ulcer healing when used in addition to multilayer compression bandaging. The clinical benefits of other medications remain unproven. Reliability of meta-analyses was limited by study heterogeneity, small sample sizes and lack of long-term follow-up. In prospective randomized studies, MPFF (Daflon(®)), other flavonoid derivatives and pentoxifylline have demonstrated clinical benefits in patients with C4-C6 venous disease. Pharmacotherapy should be part of a range of treatment options in the modern management of patients with chronic venous disorders.

Protocol for a pilot randomised controlled clinical trial to compare the effectiveness of a graduated three layer straight tubular bandaging system when compared to a standard short stretch compression bandaging system in the management of people with venous ulceration: 3VSS2008

BackgroundThe incidence of venous ulceration is rising with the increasing age of the general population. Venous ulceration represents the most prevalent form of difficult to heal wounds and these problematic wounds require a significant amount of health care resources for treatment. Based on current knowledge multi-layer high compression system is described as the gold standard for treating venous ulcers. However, to date, despite our advances in venous ulcer therapy, no convincing low cost compression therapy studies have been conducted and there are no clear differences in the effectiveness of different types of high compression.Methods/DesignThe trial is designed as a pilot multicentre open label parallel group randomised trial. Male and female participants aged greater than 18 years with a venous ulcer confirmed by clinical assessment will be randomised to either the intervention compression bandage which consists of graduated lengths of 3 layers of elastic tubular compression bandage or to the short stretch inelastic compression bandage (control). The primary objective is to assess the percentage wound reduction from baseline compared to week 12 following randomisation. Randomisation will be allocated via a web based central independent randomisation service (nQuery v7) and stratified by study centre and wound size ≤ 10 cm2 or >10 cm2. Neither participants nor study staff will be blinded to treatment. Outcome assessments will be undertaken by an assessor who is blinded to the randomisation process.DiscussionThe aim of this study is to evaluate the efficacy and safety of two compression bandages; graduated three layer straight tubular bandaging (3L) when compared to standard short stretch (SS) compression bandaging in healing venous ulcers in patients with chronic venous ulceration. The trial investigates the differences in clinical outcomes of two currently accepted ways of treating people with venous ulcers. This study will help answer the question whether the 3L compression system or the SS compression system is associated with better outcomes.Trial RegistrationACTRN12608000599370

Improving venous ulcer healing: designing and reporting randomised controlled trials

The randomised controlled trial (RCT) is often considered the gold standard for judging the benefits of treatments. The application of randomised controlled clinical trials to treatments of venous ulcer healing has lagged behind that of other areas of medicine. To interpret the results of an RCT, readers must understand a variety of aspects of their design, analysis and interpretation. Venous ulcer disease has a high prevalence and has a significant socioeconomic impact in most parts of the world. The management of venous ulcers causes a considerable strain on the health system and is likely to worsen in future. The multi-layer high compression system is described as the current gold standard for treating venous ulcers. A recent meta-analysis of bandaging systems found that multi-layer compression bandages appeared to be superior to single-layer bandages in promoting venous ulcer healing. However, it was noted that many of the studies had small sample sizes and the quality of research in the area was poor. The consolidating standards of reporting trials (CONSORT) statement can help clinicians to discern high-quality studies from ones of poorer quality. This paper discusses how CONSORT can help clinicians and researchers to design and report quality studies to contribute to evidence-based venous ulcer healing.

The role of perforators in chronic venous insufficiency

The treatment of incompetent calf perforating veins (ICPVs) has been ascribed an important role in the therapeutic strategy for reducing superficial venous hypertension in patients with advanced chronic venous insufficiency (C4-C6). Since the open approach to ligation of ICPVs was developed by Linton over 70 years ago, there has been an evolution toward less invasive techniques with lower morbidity. This paper will review the evidence for interruption of ICPVs through a series of systematic analyses of (1) subfascial endoscopic perforating surgery (SEPS) and (2) percutaneous thermal ablation techniques (PAPS). The effectiveness and morbidity of each approach will be discussed as well as the strength of evidence supporting that technique. While there are numerous case series that suggest that SEPS is beneficial for ulcer healing and for the prevention of ulcer recurrence, the sole two RCTs that have compared either open division or SEPS for ICPVs have failed to show a statistical advantage for ICPV ablation. The results of these studies are clouded by the inclusion of patients who received concomitant treatment of their great saphenous vein (GSV). The evidence for PAPS is based on a few (n = 5) case series in peer-reviewed journals, which are limited by small patient populations, limited follow-up, and a focus on surrogate outcomes (occlusion of the perforator) rather than clinical or functional outcomes. Moreover, most of these series were carried out in patients with mild disease. Sclerotherapy of ICPVs, by either liquid or foam, shows promise, but requires greater evidence. Our current approach for limbs with C4-C6 disease is to treat the GSV first and limit treatment of ICPVs to those with high volume flow and large-diameter ICPVs. [corrected]

Comparison of the effectiveness of compression stockings and layer compression systems in venous ulceration treatment.

IntroductionThe aim of the research was to compare the dynamics of venous ulcer healing when treated with the use of compression stockings as well as original two- and four-layer bandage systems.Material and methodsA group of 46 patients suffering from venous ulcers was studied. This group consisted of 36 (78.3%) women and 10 (21.70%) men aged between 41 and 88 years (the average age was 66.6 years and the median was 67). Patients were randomized into three groups, for treatment with the ProGuide two-layer system, Profore four-layer compression, and with the use of compression stockings class II. In the case of multi-layer compression, compression ensuring 40 mmHg blood pressure at ankle level was used.ResultsIn all patients, independently of the type of compression therapy, a few significant statistical changes of ulceration area in time were observed (Student’s t test for matched pairs, p < 0.05). The largest loss of ulceration area in each of the successive measurements was observed in patients treated with the four-layer system – on average 0.63 cm2/per week. The smallest loss of ulceration area was observed in patients using compression stockings – on average 0.44 cm2/per week. However, the observed differences were not statistically significant (Kruskal-Wallis test H = 4.45, p > 0.05).ConclusionsA systematic compression therapy, applied with preliminary blood pressure of 40 mmHg, is an effective method of conservative treatment of venous ulcers. Compression stockings and prepared systems of multi-layer compression were characterized by similar clinical effectiveness.

Risk factors related to the failure of venous leg ulcers to heal with compression treatment

Compression therapy is the most widely used treatment for venous leg ulcers and it was used in different forms for more than 400 years. Published healing rates of venous ulcers obtained with compression therapy vary widely from 40-95%. According to numerous studies, it has been suggested that the application of external pressure to the calf muscle raises the interstitial pressure resulting in improved venous return and reduction in the venous hypertension. Several risk factors have been identified to be correlated with the failure of venous leg ulcers to heal with compression therapy (longer ulcer duration; large surface area; fibrinous deposition present on >50% of the wound surface and an Ankle Brachial Pressure Index (ABPI) of <0.85. An open prospective single-center study was performed in order to determine possible risk factors associated with the failure of venous ulcers to heal when treated with multi-layer high compression bandaging system for 52 weeks. In the study, 189 patients (101 women, 88 men; mean age 61 years) with venous leg ulcers (ulcer surface >5 cm(2); duration >3 months) were included. The study excluded patients with arterial disease (ABPI <0.8), heart insufficiency with ejection fraction (EF) <35, pregnancy, cancer disease, rheumatoid arthritis, and diabetes. Based on clinical opinion and available literature, the following were considered as potential risk factors: sex, age, ulceration surface, time since ulcer onset, previous operations, history of deep vein thrombosis, body mass index (BMI), reduction in calf circumference >3 cm during the first 50 days of treatment, walking distance during the day <200 meters, calf:ankle circumference ratio <1.3, fixed ankle joint, history of surgical wound debridement, >50% of wound covered with fibrin, depth of the wound >2 cm. Within 52 weeks of limb-compression therapy, 24 (12.7%) venous ulcers had failed to heal. A small ulceration surface (<20 cm(2)), the duration of the venous ulcer <12 months, a decrease in calf circumference of more than 3 cm, and emergence of new skin islets on >10% of wound surface during the first 50 days of treatment were favorable prognostic factors for ulcer healing. A large BMI (>33 kg/m(2)), short walking distance during the day (<200 m), a history of wound debridement, and ulcers with deepest presentation (>2 cm) were indicators of slow healing. Calf:ankle circumference ratio <1.3, fixed ankle joint, and reduced ankle range of motion were the only independent parameters associated with non-healing (P < .001). The results obtained in this study suggest that non-healing venous ulcers are related to the impairment of the calf muscle pump.

The relationship between cytokine concentrations and wound healing in chronic venous ulceration

The importance of wound cytokine function in chronic venous leg ulcers remains poorly understood. This study evaluated the relationship between local and systemic concentrations of wound cytokines and wound healing in patients with chronic venous ulceration. This prospective observational study was set in a community- and hospital-based leg ulcer clinic. Consecutive patients with chronic leg ulceration and ankle-brachial pressure index >0.85 were prospectively investigated. All patients were treated with multilayer compression bandaging. Wound fluid and venous blood samples were collected at recruitment and 5 weeks later. In the wound fluid and venous blood, cytokines and factors reflecting the processes of inflammation (interleukin 1beta, tumor necrosis factor-alpha), proteolysis (matrix metalloproteinases-2 and -9), angiogenesis (basic fibroblast growth factor [bFGF], vascular endothelial growth factor), and fibrosis (transforming growth factor-beta(1) [TGFbeta(1)]) were measured. Ulcer healing was assessed using digital planimetry at both assessments. The study comprised 80 patients (43 men, 37 women). Median (range) ulcer size reduced from 4.4 (0.1-142.4) cm(2) to 2.2 (0-135.5) cm(2) after 5 weeks (P < .001; Wilcoxon signed rank), although 17 of 80 ulcers increased in size. The volume of wound fluid collected strongly correlated with ulcer size (Spearman rank = 0.801, P < .01). Initial wound fluid concentrations of bFGF correlated with ulcer size (Pearson coefficient = 0.641, P < .01), and changes in wound fluid TGFbeta(1) concentrations inversely correlated with changes in ulcer size (Spearman rank = -0.645, P = .032). There were no significant correlations between changes in other factors and ulcer healing. Wound fluid and serum cytokine concentrations correlated poorly. Wound fluid collection volume correlates with ulcer size. Ulcer healing correlated with increased concentrations of TGFbeta(1), possibly reflecting increased fibrogenesis in the proliferating wound. Aside from this, there was a large variation in wound and serum cytokine levels that largely limits their usefulness as markers of healing.

145 Interval Analysis of a Randomized, Open Label, Multi-Center Study Comparing Apligraf Vs. Standard Multilayer Compression in the Reduction of Pain Associated WItH Venous Leg Ulcerations

Background: According to The American Pain Society, pain should be considered a fifth vital sign. Pain is a prominent feature of venous leg ulcerations (VLUs). Sixty-five percent of VLU patients complain of severe pain. In several multicenter clinical trials, Apligraf, a bioengineered living skin construct, has been shown to accelerate healing in venous leg ulcerations. Anecdotal clinical observations suggest that Apligraf treatment is associated with pain relief. A treatment modality which promotes healing and reduces pain would significantly improve the quality of life in patients with VLU. Methods: VLU patients with pain scores greater than 5/10 on a numerical scale or requiring narcotic analgesia were randomized to receive either Apligraf and compression or compression alone. There was a 3-week “wash-out” period to ensure that pain was not due to other factors such as inadequate compression or infection. Patients were enrolled only after a negative quantitative biopsy. The intensity of pain was self-scored and a quality-of-life questionnaire was completed at each visit. Weekly wound area measurements were obtained with digital planimetry. Results: Thus far in the enrollment period we have already seen a trend toward a significant reduction in pain in the Apligraf group. This pain relief occurs shortly after application indicating that a mechanism distinct from clinical healing. The Apligraf group also demonstrated acceleration in wound healing as well as a decreased time-to-complete closure. Conclusion: Interval analysis of this multicenter trial suggests that Apligraf accelerates wound healing and reduces the pain associated with venous leg ulcerations. Acknowledgment: Unrestricted Educational grant, Organogenesis Inc.

Effectiveness of acupuncture, special dressings and simple, low-adherence dressings for healing venous leg ulcers in primary healthcare: study protocol for a cluster-randomized open-labeled trial

BackgroundVenous leg ulcers constitute a chronic recurring complaint that affects 1.0–1.3% of the adult population at some time in life, and which corresponds to approximately 75% of all chronic ulcers of the leg. Multilayer compression bandaging is, at present, the only treatment that has been proved to be effective in treating this type of ulcer. There is no consensus, however, about the dressings that may be applied, beneath the compression, to promote the healing of this type of ulcer, as there does not seem to be any added benefit from using special dressings rather than simple, low-adherence ones. As well as analgesia, acupuncture provokes peripheral vasodilation, in skin and muscles – which has been demonstrated both experimentally and in clinical practice – probably due to the axon reflex, among other mechanisms. The aim of the present study is to measure the effectiveness and cost of compression treatment for venous leg ulcers combined with special dressings, in comparison with low-adherence ones and acupuncture.Methods/designCluster-randomized open-labeled trial, at 15 primary healthcare clinics in the Sevilla-Sur Healthcare District, with a control group treated with compression bandaging and low-adherence dressings; the experiment will consist, on the one hand, of the compression treatment applied in combination with special dressings (Treatment 1), and on the other, the compression treatment applied in association with low-adherence dressings, together with acupuncture (Treatment 2).DiscussionThe results will be measured and recorded in terms of the median time elapsed until complete healing of the ulcer, and the rate of complete healing at 3 months after beginning the treatment. An economic analysis will also be made.This study, carried out in the context of real clinical practice, will provide information for decision-taking concerning the effectiveness of special dressings. Moreover, for the first time a high-quality study will evaluate the effectiveness of acupuncture in the process of healing venous leg ulcers.Trial registrationCurrent Controlled Trials ISRCTN26438275.

Multilayer compression bandaging in the acute phase of deep-vein thrombosis has no effect on the development of the post-thrombotic syndrome

The purpose of this randomized study was to evaluate the influence of immediate multilayer compression bandages before application of elastic stockings in the acute phase of deep-vein thrombosis (DVT) on development of the post-thrombotic syndrome (PTS). Sixty-nine patients with acute symptomatic DVT were randomized to immediate bandaging (n = 34) or no bandaging (n = 35). After reduction of edema sized-to-fit elastic stockings were applied in all patients after 7-14 days. Follow-up visits and non-invasive examinations were planned after 7, 30 and 90 days and 1 year. Venous outflow resistance (VOR) was measured by strain gauge plethysmography. Thrombosis score (TS) and reflux were measured by duplex scanning. After one year patients were evaluated for clinical PTS using both the clinical scale of the CEAP classification and the Villalta score. Improvement of clinical symptoms and decrease of leg circumference was better on day 7 in the bandaging group, but after 1 and 3 months clinical symptoms had improved equally in both groups. In 7 patients in the no-bandaging group a bandage was applied after all because of persistent edema after 10 days. There were no differences in VOR, TS and reflux. Using the CEAP classification the incidence of PTS was 39% in patients with bandages and 42% in patients without bandages (RR 0.91, 95% CI 0.50-1.66). Using the Villalta score the incidence of PTS was resp. 29 and 33% (RR 0.87, 95% CI 0.41-1.8). There was no difference in severity of PTS. Immediate multilayer compression bandaging in the acute phase of DVT is effective in reducing edema and complaints in the first week, but has no effect on thrombus regression, valve incompetence and the development of clinical PTS after 1 year.

The ulcerated leg severity assessment score for prediction of venous leg ulcer healing

Conclusion: The Ulcerated Leg Severity Assessment (ULSA) score identifies patients with venous ulcers unlikely to respond to conventional treatment. Summary: Most, but not all, venous ulcers will heal with compression therapy. The authors sought to develop an assessment score to potentially identify patients whose ulcers would not heal with conventional compression therapy and, therefore, should perhaps be offered alternative therapy for ulcer healing early in their course. Baseline factors affecting venous ulcer healing were assessed in patients with venous ulcers seen between March 1999 and August 2001. All patients were initially treated with multilayer compression therapy. Variables related to 24-week healing were identified, and a Cox regression model was developed to identify risk factors that predicted ulcer healing. From this model, a scoring system was developed and subsequently prospectively validated between February 2004 and March 2005. The baseline study included 229 patients with venous ulcers. Patient age, ulcer chronicity, and venous refill time (VRT) of ≤20 seconds were identified as risk factors for nonhealing. The authors used these risk factors and hazard ratios from the Cox analysis and derived the following formula: Ulcerated Leg Severity Assessment (ULSA) score = age + chronicity – 50 (when VRT is >20 seconds). Patients with an ULSA score ≤50 had higher 24-week ulcer-healing rates than those with scores >50. This was in both the baseline study (P < .001) and the follow-up prospective validation study performed in 86 patients (P = .007). Comment: Optimal therapy for venous ulceration continues to be debated. The authors suggest that an elevated ULSA score may indicate patients who early in the course of treatment may benefit from therapies other than compression therapy. Their data, however, shows no benefit with use of these “alternative” therapies. It only identifies individuals who will not do well with compression therapy. It certainly cannot be assumed patients who do not do well with compression therapy will be benefited by alternative therapies. Alternative therapies may also not work well in patients with elevated ULSA scores.

A point prevalence survey of wounds in north-east England

To review current wound-care practice and the standard of wound care in Hull and East Yorkshire; obtain information on prevalence, treatment and outcomes; provide a basis for estimating the extent of the problem, treatment modalities used, service provision and future needs; highlight areas of care in need of improvement; highlight areas with excellent wound practices and gain information for future research projects within the population of the region. Point prevalence interface audit of community and acute trusts. The cumulative wound prevalence for the region was 12%. Community nurses were involved in caring for 70.1% of patients with wounds, with 52.7% of wounds being treated in the patient's home. The largest proportion of wounds were surgical wounds (n=699, 41.5%), followed by leg and foot ulcers (n=629, 37.3%) and pressure ulcers (n=294, 17.4%). Diabetes and cancer were related to 15.1% and 9.7% of the wounds respectively. 41.9% of the wounds were on the lower leg. The primary and secondary dressings used the most were low/non-adherent dressings at 25.9% and 27.3% respectively.Almost half of the patients with a venous leg ulcer (46%) did not receive multilayer compression and 7% of patients with an arterial ulcer did; 23.6% of the leg and foot wounds were not assessed with a Doppler. Wounds represent a significant cause of morbidity in the general population.A systematic focus is necessary on effective and timely diagnosis, on ensuring treatment is appropriate to the cause and condition of the wound and on active measures to prevent complications.A number of initiatives have commenced in order to provide a effective and efficient wound care.

A randomized trial of the Tubulcus multilayer bandaging system in the treatment of extensive venous ulcers

Venous ulcers are a major health problem because of their high prevalence and associated high cost of care. Compression therapy is the most widely used treatment for this condition. The vast majority of published articles on compression therapy present the results in the treatment of venous ulcers usually up to 15 to 20 cm(2). However, there are no published data in English medical literature on the efficacy of compression therapy in the treatment of extensive venous ulcers (ulcers >20 cm(2) of more than 6 months' duration) with regard to healing rate, time to healing, and recurrence rate at 12 months after healing. A total of 138 patients with extensive venous ulceration (ulceration surface, 20-210 cm(2); duration, 7 months to 28 years) were randomized into 2 groups: (1) a treatment group (72 patients who were treated by using a multilayer bandaging system with the Tubulcus (a heelless open-toed elastic compression device knitted in tubular form) and elastic bandages and (2) a control group (66 patients treated with a multilayer bandaging system with elastic bandages only). The patients were treated on an ambulatory basis; the primary end point of the study was complete ulcer healing at 500 days. The secondary end point was to assess the ulcer recurrence rate during continuation of below-knee compression of different degrees of compression. In the treatment group, patients were instructed to continue to wear the Tubulcus (35 mm Hg), and patients in the control group were instructed to wear compression stockings with compression of 20 to 25 mm Hg. The exclusion criteria from the study were heart insufficiency with an ejection fraction <35, an ankle-brachial pressure index less than 0.8, and pregnancy. The cumulative healing rate was 93% in the treatment group and was 51% in the control group (P < .001). The median healing time in the treatment group was 133 days (range, 28 to 464 days), and in the control group it was 211 days (range, 61 to 438 days). The recurrence rate at 12 months in the treatment group was 24% (16/67) and was 53% (18/34) in the control group (P < .05). After additional compression treatment with the same treatment protocol, all 16 recurrent ulcers in the treatment group healed. In the control group, the healing rate of recurrent ulcers was 89% (16/18). This study suggests that for extensive venous ulceration, multilayer compression therapy with the Tubulcus provides an extremely high healing rate. Compression of more than 30 mm Hg results in decreased ulcer recurrence. However, recurrence cannot be completely avoided.

A Multilayer Data Copy Test Data Compression Scheme for Reducing Shifting-in Power for Multiple Scan Design

The random-like filling strategy pursuing high compression for today's popular test compression schemes introduces large test power. To achieve high compression in conjunction with reducing test power for multiple-scan-chain designs is even harder and very few works were dedicated to solve this problem. This paper proposes and demonstrates a multilayer data copy (MDC) scheme for test compression as well as test power reduction for multiple-scan-chain designs. The scheme utilizes a decoding buffer, which supports fast loading using previous loaded data, to achieve test data compression and test power reduction at the same time. The scheme can be applied automatic test pattern generation (ATPG)-independently or to be incorporated in an ATPG to generate highly compressible and power efficient test sets. Experiment results on benchmarks show that test sets generated by the scheme had large compression and power saving with only a small area design overhead.

Characterization of Tableting using the OSDRC System

We compared the compression properties and characteristics of tablets obtained using the OSDRC system (method (OSDRC)) and conventional compression methods including multi-layer compression with a pharmaceutical powder. We prepared tablets using four methods of compression. The force profiles, ejection force, stress relaxation, pressure transmission ratio, and internal intensity of the tablets were measured as compression properties. Method (OSDRC) gave the highest value for the crushing strength of the tablets. Although the compression properties were similar regardless of the method of compression, the internal intensity of tablets compressed by method (OSDRC) was significantly larger than that of the tablets produced by the other methods. In terms of crushing strength, the tablets compressed by method (OSDRC) were superior of those obtained by the conventional compression method. Therefore, it is possible to increase the crushing strength of tablets without changing the pharmaceutical formulation.

Microbioreactors for Bioprocess Development

As a step toward high-throughput bioprocess development, we present design, fabrication, and characterization of polymer based microbioreactors integrated with automated sensors and actuators. The devices are realized, in increasing levels of complexity, in poly(dimethylsiloxane) and poly(methyl methacrylate) by micromachining and multilayer thermal compression bonding procedures. Online optical measurements for optical density, pH, and dissolved oxygen are integrated. Active mixing is made possible by a miniature magnetic stir bar. Plug-in-and-flow microfluidic connectors and fabricated polymer micro-optical lenses/connectors are integrated in the microbioreactors for fast set up and easy operation. Application examples demonstrate the feasibility of culturing microbial cells, specifically Escherichia coli, in 150 μL-volume bioreactors in batch, continuous, and fed-batch operations. (JALA 2007;12:143–51)