Effects of compression and type of bed surface on the microcirculation of the heel

An novel and alternative treatment method for large heel ulceration in diabetic patients: Proximal tibial cortex transverse distraction

Heel ulceration in patients with diabetes mellitus (DM) is a major clinical challenge, manifesting with a protracted and uncertain healing process. The prefer treatment of heel ulceration is still controversial. This study aims at describing a newly alternative surgical method with the proximal transverse tibial bone transport technique, as an attempt to achieve wound healing in diabetic patients with large heel ulceration. Retrospective clinical study. A total of 21 diabetic patients with large heel ulceration were enrolled and followed up at least 6 months. The following parameters were assessed: Visual analogue scale (VAS), healing time, ulcer healing rate, ulcer recurrence rate and limb salvage rate. All patients got fully follow-up and achieved wound healing uneventfully. Eighteen patients returned to independent walking without any helper while three patients walked using a crutch. Limb salvage was achieved in all 21 patients (100%). The mean wound area was 67.43 ± 13.31 cm2 (range: 46-97 cm2 ). The mean healing time was 128.62 ± 16.76 days (range: 91-160 days). 16 out of 21 patients without calcaneal osteomyelitis achieved ulcer healing with a mean duration of 124.69 ± 14.42 days (range: 91-143 days), while the other five patients with calcaneal osteomyelitis were 141.20 ± 19.12 days (range: 110-160 days). 2 out of 21 patients got superficial rupture at the previous wounds and healed after outpatient dressing change combined with oral antibiotics. The novel technique described is particularly applicable for large heel ulceration in diabetic patients. It offers a better alternative for achieving wound healing with a favourable encouraging outcome.

The effect of pressure and shear on tissue viability of human skin in relation to the development of pressure ulcers: a systematic review

Pressure ulcers are a significant problem in health care, due to high costs and large impact on patients' life. In general, pressure ulcers develop as tissue viability decreases due to prolonged mechanical loading. The relation between load and tissue viability is highly influenced by individual characteristics. It is proposed that measurements of skin blood flow regulation could provide good assessment of the risk for pressure ulcer development, as skin blood flow is essential for tissue viability. . Therefore, the aim of this systematic review is to gain insight in the relation between mechanical load and the response of the skin and underlying tissue to this loading measured in-vivo with non-invasive techniques. A systematic literature search was performed to identify articles analysing the relation between mechanical load (pressure and/or shear) and tissue viability measured in-vivo. Two independent reviewers scored the methodological quality of the 22 included studies. Methodological information as well as tissue viability parameters during load application and after load removal were extracted from the included articles and used in a meta-analysis. Pressure results in a decrease in skin blood flow parameters, compared to baseline; showing a larger decrease with higher magnitudes of load. The steepness of the decrease is mostly dependent on the anatomical location. After load removal the magnitude of the post-reactive hyperaemic peak is related to the magnitude of pressure. Lastly, shear in addition to pressure, shows an additional negative effect, but the effect is less apparent than pressure on skin viability.

Diabetic neuropathic forefoot and heel ulcers: management, clinical presentation and outcomes

OBJECTIVE

The two most common sites for diabetic neuropathic foot ulcers are the forefoot and the heel. Each site has special characteristics that determines its course. The aim of this study is to compare clinical presentation, management and outcome of diabetic neuropathic forefoot ulcers to diabetic neuropathic heel ulcers.

METHOD

This was a prospective cross-sectional comparative study carried in Jabir Abu Eliz Diabetic Centre (JADC), Khartoum, Sudan. A hundred patients with neuropathic diabetic ulcer were included, half were forefoot ulcers and the other half were hindfoot ulcers, two patients were lost on follow-up from each group. Neuropathy was graded using 10g monofilament nylon. Patients with vascular ischaemia, ankle brachial index pressure (ABPI) <0.9 and >1.1 were excluded. Other patient's data included demographic, foot and ulcer characteristics, comorbidities and outcomes. Foot ulcers were categorised according to Wagner classification, site and size of ulcer and presence of infection. Comorbidities evaluated included hypertension, ischaemic heart disease and renal impairment. All patients received standard wound care and regular follow-up.

RESULTS

The age of the studied patients was 54.3 ± 11 years (mean ± standard deviation (SD 11)) and 52.9 ± 11 years for forefoot and heel ulcer respectively. The mean duration of diabetes was 12.4 ± 6 years for forefoot ulcers and 13.3 ± 7 years for heel ulcer. The mean duration of foot ulcer was 21 and 26 days for forefoot and heel respectively. Forefoot ulcers healed within 12 week in 45% of patients and by 20 weeks in 63%, while 35% of heel ulcers healed by 12 weeks and 54% healed by 20 weeks (p=0.058). Based on Wagner classification, healing was best in class 1 among both forefoot and heel ulcers, 22.4% and 12.2% respectively (p=0.003 for forefoot and 0.002 for heel). First and second metatarsal heads were the common site of forefoot ulcer. Heel ulcers >3cm dimension had longer duration of healing compared to forefoot ulcers at both 12 and 20 weeks (p<0.02).

CONCLUSION

Healing in diabetic neuropathic forefoot ulcer was better than heel ulcer, though not reaching statistically significant value. Wagner class 1 had the best healing among both ulcers and a heel ulcer >3cm had a significantly longer healing time.

DECLARATION OF INTEREST

The authors have no conflict of interest to declare.

Effect of compression stockings on cutaneous microcirculation: Evaluation based on measurements of the skin thermal conductivity

Objective

To study of the microcirculatory effects of elastic compression stockings.

Materials and methods

In phlebology, laser Doppler techniques (flux or imaging) are widely used to investigate cutaneous microcirculation. It is a method used to explore microcirculation by detecting blood flow in skin capillaries. Flux and imaging instruments evaluate, non-invasively in real-time, the perfusion of cutaneous micro vessels. Such tools, well known by the vascular community, are not really suitable to our protocol which requires evaluation through the elastic compression stockings fabric. Therefore, we involve another instrument, called the Hematron (developed by Insa-Lyon, Biomedical Sensor Group, Nanotechnologies Institute of Lyon), to investigate the relationship between skin microcirculatory activities and external compression provided by elastic compression stockings. The Hematron measurement principle is based on the monitoring of the skin’s thermal conductivity. This clinical study examined a group of 30 female subjects, aged 42 years ±2 years, who suffer from minor symptoms of chronic venous disease, classified as C0s, and C1s (CEAP).

Results

The resulting figures show, subsequent to the pressure exerted by elastic compression stockings, an improvement of microcirculatory activities observed in 83% of the subjects, and a decreased effect was detected in the remaining 17%. Among the total population, the global average increase of the skin’s microcirculatory activities is evaluated at 7.63% ± 1.80% ( p < 0.0001).

Conclusion

The results from this study show that the pressure effects of elastic compression stockings has a direct influence on the skin’s microcirculation within this female sample group having minor chronic venous insufficiency signs. Further investigations are required for a deeper understanding of the elastic compression stockings effects on the microcirculatory activity in venous diseases at other stages of pathology.

Heel blood flow during loading and off-loading in bedridden older adults with low and normal ankle-brachial pressure index: a quasi-experimental study

The purpose of this study was to evaluate the differences in heel blood flow during loading and off-loading in bedridden adults older than 65 years. The patients were divided into three groups based on ankle-brachial pressure index (ABI) and transcutaneous oxygen tension (tcPO₂): (1) patients with an ABI ≥ 0.8 (Group A); (2) patients with an ABI < 0.8 and heel tcPO₂ ≥ 10 mmHg (Group B); and (3) patients with an ABI < 0.8 and heel tcPO₂ < 10 mmHg (Group C). Heel blood flow was monitored using tcPO₂ sensors. Data were collected with the heel (1) suspended above the bed surface (preload), (2) on the bed surface for 30 min (loading), and (3) again suspended above the bed surface for 60 min (off-loading). Heel blood flow during off-loading was assessed using three parameters: oxygen recovery index (ORI), total tcPO₂ for the first 10 min, and change in tcPO₂ after 60 min of off-loading. ORI in Group C (n = 8) was significantly shorter than in Groups A (n = 22) and B (n = 15). Total tcPO₂ for the first 10 min of off-loading in Group C was significantly less than that in Groups A and B. Change in tcPO₂ after 60 min of off-loading in Group C was less than in Group A. Based on these findings, additional preventive care against heel blood flow decrease in older adults with an ABI < 0.8 and heel tcPO₂ < 10 mmHg might be necessary after loading.

The heel: anatomy, blood supply, and the pathophysiology of pressure ulcers

There remains much confusion regarding the pathophysiology of pressure ulcers. Data indicate that the prevalence of pressure ulcers is increasing. The heel is unique in structure and well adapted to the task of shock absorption. However, it is often subject to prolonged pressure, which predisposes it to tissue breakdown, with attempts at reconstruction prone to failure. Four dissections were carried out of the heel region, which included removing each heel pad en bloc for histology. Seventeen arterial injection studies, 12 venous studies, and a combined arterial and venous study of the foot were performed. The results were correlated with clinical cases and previous research. The heel was found to be richly vascularized by a subdermal plexus and periosteal plexus with vessels traveling between the 2 within fibrous septa that connect the reticular dermis and periosteum of the calcaneus. These septa effectively create isolated compartments containing relatively avascular fat. A layer of panniculus carnosus muscle was observed in the subcutaneous tissue. It is likely that the metabolically active panniculus carnosus muscle is involved early in the course of pressure ulcers. Extensive pressure damage can be concealed by intact skin. Friction and shear are additional factors important in skin breakdown.

Effects of support surface relief pressures on heel skin blood perfusion

OBJECTIVE

To investigate the effect of pressure-relief magnitude on heel blood flow.

DESIGN

12 healthy subjects (5 male, 7 female; 21 to 43 years of age) lay on a support surface for 50 minutes with 1 heel on the end cell of the support surface. Cell pressure was computer controlled to vary cyclically at 5-minute intervals between a constant 20 mm Hg during loading and 10, 5, and 0 mm Hg during off-loading. Heel skin blood perfusion was monitored by laser Doppler probes on the heel and foot dorsum. Average skin blood perfusion during each 10-minute cycle and the hyperemic response after pressure relief were determined absolutely and relative to baseline.

SETTING

University research center.

RESULTS

An inverse relationship was found between relief pressure and heel skin blood perfusion over each pressurization-relief cycle and during the hyperemia phase. Full-cycle average skin blood perfusion associated with release to 0, 5, and 10 mm Hg were 34.1 +/- 7.5 arbitrary units (AU), 26.4 +/- 7.5 AU, and 9.3 +/- 3.3 AU, respectively (P <.001).

CONCLUSIONS

The reduced average skin blood perfusion is attributable to blunting of hyperemia when relief pressure is too high. When it corresponded to an interface pressure near diastolic pressure, little, if any, functional pressure relief or hyperemia is realized. Suitable relief pressures are likely dependent on an individual's diastolic blood pressure and the net tissue forces acting on heel blood vessels. This suggests that lower blood pressures need lower pressure-relief levels. It is suspected that if depressed vascular responsiveness and/or diminished hyperemic reserve is also present, even lower relief pressures are needed.

Effects of different cyclic pressurization and relief patterns on heel skin blood perfusion

OBJECTIVE

It was hypothesized that a device or support surface providing intermittent cycles of pressurization and pressure relief might minimize the impact of blood flow deficits in the heels resulting from the application of pressure. Because this possibility depends on whether pressure-relief hyperemia can adequately compensate for blood flow deficits, the main objective was to determine how different temporal patterns of pressurization and pressure relief would affect average skin blood perfusion of the heels.

DESIGN

Using a laser Doppler, skin blood perfusion was measured in the heels of 20 healthy subjects while they lay supine for 80 minutes on a support surface. The end cell supporting the heel produced 3 different cyclic patterns of pressurization and either full or partial pressure relief. Each pattern of 1, 2, or 4 cycles was contained within contiguous 20-minute intervals. Skin blood perfusion was determined during full pressurization and during pressure relief for 2 protocols with 10 subjects each.

SETTING

University research center.

MAIN OUTCOME MEASURE

Overall average skin blood perfusion in relation to baseline.

RESULTS

Full pressure relief yielded a significantly greater skin blood perfusion than partial relief. However, whether pressure relief was full or partial, the average skin blood perfusion of each cyclic pattern was greater than baseline.

CONCLUSION

Consistent with the proposed hypothesis, pressure-relief cycles resulted in an average heel skin blood perfusion that was greater than resting baseline. In the healthy subjects studied, this occurred because hyperemia during pressure relief compensated for flow deficits during pressurization. These results are applicable when the patient is capable of a normal physiologic hyperemic response. The next major investigative challenge is to examine the impact of pressure-relief cycles on patients with diminished hyperemic reserve.

Hospital-acquired heel ulcers: a common but neglected problem

The development of hospital-acquired pressure ulcers on the heel is a growing problem. The best way of preventing this is to ensure the heel is completely free from pressure.