|Year : 2020 | Volume
| Issue : 4 | Page : 385-388
Interest of a standardized treadmill test to evaluate pressure drops and stiffness indices under short stretch bandages
Ravul Jindal1, Florence Balet2, Pascal Filori3, Taranvir Kaur1, Shabjot Dhillon1, Shiwangi Thapa1, Piyush Chaudhary1
1 Department of Vascular Surgery, Fortis Hospital Mohali, Sahibzada Ajit Singh Nagar, Punjab, India
2 Nurse, Salon de Provence, France
3 Physiotherapist, Marseille, France
|Date of Submission||13-Apr-2020|
|Date of Acceptance||21-Apr-2020|
|Date of Web Publication||24-Dec-2020|
Department of Vascular Surgery, Fortis Hospital Mohali, Sahibzada Ajit Singh Nagar, Punjab
Source of Support: None, Conflict of Interest: None
Introduction: Under short stretch bandages (SSB), the pressures drop over time. These pressures are documented in non standardized-way and vary from one study to another. Objective: A standardized stress test on a treadmill should help to better understand this evolution and thus to document with more precision the behavior of 3 bandages in use. Materials and Methods: Three bandage kits (Urgo K2, Kit Biflex and a kit consisting of padding + 2 cotton SSB2 were tested in 30 subjects (60 legs) before and after a treadmill test (3 km/h, 6% slope for 30 min or 1.5 km). Results: Before the test, the bandages were applied with nonsignificantly different resting interface pressures (respectively 40.58 ± 2.7 mmHg, 41.05 ± 2.17 mmHg, 38.16 ± 2.98 mmHg). When standing, the pressures were significantly different between Urgo K2, Kit Biflex and SSB2(55.58 ± 6.15 mmHg, 57.3 ± 6.53 mmHg versus 62.3 ± 5.07 mmHg for SSB2). Similarly, the static stiffness indexes (SSI) showed significant differences (15 ± 5.05mmHg and 16.25 ± 6.28 mmHg versus 24.13 ± 4.65 mmHg for SSB2). After the test, resting pressures drop but more significantly under the SSB2 compared to the other 2 multilayer bandages (resting pressures: 31.95 ± 2.66 mmHg and 34.61 ± 2.28 mmHg vs. 25.95 ± 3.15 mmHg for SSB2). However, the SSI is not significantly different from the SSI calculated before the treadmill test (15.41 ± 4.44 mmHg and 15.66 ± 4.85 mmHg vs. 25.06 ± 4.98 mmHg). Conclusions: The treadmill test makes it possible to quantify and to compare the drop in pressure under different bandages in the same conditions. This test could be useful in clinical research before the clinical phases of development, especially in the case of venous leg ulcer. On the other hand, in case of mixed ulcers, the drop in pressure in lying position in multilayer bandages ensure a continuation of the arterial influx in case of mixed ulcers.
Keywords: Compression bandages, interface pressure, stiffness, treadmill test
|How to cite this article:|
Jindal R, Balet F, Filori P, Kaur T, Dhillon S, Thapa S, Chaudhary P. Interest of a standardized treadmill test to evaluate pressure drops and stiffness indices under short stretch bandages. Indian J Vasc Endovasc Surg 2020;7:385-8
|How to cite this URL:|
Jindal R, Balet F, Filori P, Kaur T, Dhillon S, Thapa S, Chaudhary P. Interest of a standardized treadmill test to evaluate pressure drops and stiffness indices under short stretch bandages. Indian J Vasc Endovasc Surg [serial online] 2020 [cited 2021 Jan 17];7:385-8. Available from: https://www.indjvascsurg.org/text.asp?2020/7/4/385/304633
| Introduction|| |
Multi-layer compression bandages are considered the gold standard for bandages in the treatment of venous ulcers. However, clinical studies on venous ulcer healing rarely accurately describe the compression bandages used. They best describe the brand name, stretch, dimensions and much more rarely the laying of the bandage. However, pressures also vary greatly with the number of layers applied at one point.,,, Unlike compression stockings, it is therefore difficult to know the pressures and the SSI achieved.
The calibration of bandages certainly makes it possible to partially compensate for this defect, but the interface pressures reached remain uncertain.
In addition, the daily clinical use of the bandages shows that in the treatment of venous leg ulcers, the desired resting pressures (30–50 mmHg) are rarely respected. It is not uncommon to find that pressures reach very high levels, resulting in the risk of skin damages in the elderly in areas of the leg where there are acute angle reliefs (tibial crest, malleoli, instep, Achilles tendon).
On the other hand, the interface pressures measured during muscle rest in the lying position and during muscle contraction in the standing position make it possible to calculate a static stiffness index (SSI). The SSI is equal to the difference between the working pressure minus the resting pressure. If the SSI is greater than 10 mmHg, the bandage is said to be stiff. The higher this index is, the higher the venous ejection fraction, the greater the ejection volume and therefore the effect on the calf venous pump. In practice, the higher the stiffness index, the greater the auto-massage effect is on the sub-cutaneous tissues.
In addition, despite the recommendations, medical or nursing staff very rarely measure distal systolic pressures or ankle brachial index (ABI). In the elderly, venous ulcer is frequently associated with arterial disease in 20% of patients. If the ABI is between 0.6 and 0.9, the ulcer is a mixed ulcer (arterial and venous). In this case, the resting interface pressures under a short stretch bandage (SSB) according to different authors must be <30–40 mmHg.,
Finally, it is known that under a multi-layer compression bandage, the resting pressure decreases rapidly over time. But no standardized test has so far been able to predict this decrease and to compare different dressings under the same conditions.[13-17] This is the interest of a treadmill test that will allow to compare the evolution of pressures and stiffness indices of multilayer bandages.
Objectives of the study
Measurements at point B1 of interface pressures in lying position at rest, standing still in muscle contraction and calculation of SSI under 3 different compression bandages (SSB2, Biflex Kit, Urgo K2).
Evolution of these parameters after a standardized walking test on a treadmill.
- Comfort of the 3 different bandages before and after the treadmill test
- Study of the slippage by skin marking.
| Materials and Methods|| |
This test is a comparative test realized in a single center. Informed consent was obtained from all subjects studied before the test began. It was carried out in accordance with the World Medical Association Helsinki Declaration. The test was conducted on August 1, 2019. The choice of leg studied and bandage applied was randomly selected from a randomization list (http://www.random.org/lists/). The bandages were always different on both legs of the same subject. We studied 60 legs. Each bandage kit was therefore worn 20 times either on the left or on the right.
The inclusion criteria were:
- Subjects over 18 years of age
- Presenting a venous condition classified C0–C1 according to the Comprehensive classification system for chronic venous disorders (Clinical class, Etiology, Anatomy, Pathophysiology) or CEAP classification (subjects with no venous clinical signs or presented with spider veins).
The criteria for non-inclusion were:
- Age <18 years
- BMI >35
- Exudative skin lesions
- Patients C2 to C6 according to the CEAP classification
- Refusal to participate in the study
- Pedal distal pulses not perceived
- Subjects unable to answer questions
- Disorders of the static of the foot or posture.
Description of the population before the treadmill event
Thirty subjects of both sexes over 18 years of age were recruited in the hospital staff of Fortis Hospital in Mohali (Punjab-India) for this test [Table 1].
- The bandages: Kit Biflex (kit consisting of 2 SSB), Urgo K2 (kit consisting of a SSB and a cohesive long stretch bandage) were strictly applied according to the recommendations on the manufacturers' instruction for use and after massaging the leg in order to obtain a resting interface pressure in the lying position of 40 mmHg. SSB2 (padding + 2 cotton short bandages, 10 cm wide) was applied with an overlap of 50% and a 100% stretch and also a lying pressure of 40 mmHg
- Pressure measurements were taken at point B1 with a Picopress pressure measuring device with a 5 cm diameter measuring sensor
- A half-hour test on a treadmill. The distance covered was 1.5 km.
Parameters assessed during this test
- Interface pressures in lying position at rest, in standing position in a muscular contraction were measured at point B1 (medial face of the calf at the tip of the medial gastrocnemius muscle) under 3 different bandage kits (SSB2, Kit Biflex, Urgo K2) before and after walking on a treadmill (half an hour's walk at 3 km/h on a motorized treadmill or a distance of 1.5 km with a 6% slope). During this test, the subjects walked barefoot
- These measurements made it possible to calculate the SSI. The comfort of the 3 different bandages was also assessed before and after the treadmill test using a 10 cm long visual nonscale analogue scale. The value zero is considered very uncomfortable; the value ten to very comfortable. The slippage was studied by skin marking on the posterior aspect of the calf with a pen marker before and after the treadmill test.
The statistical analysis was performed using JMP software (version 12 pro for Mac). The comparison of the averages was tested with the Student's t-test. A value of P < 0.05 is considered significant. Our hypothesis for the test is that the differences in SSI should be in the order of 30%. We were able to calculate the number of legs per group (20 per group) using a two-way test with a α = 0.05 and aβ = 0.15.
This hypothesis is not based on published data because the differences in SSI between the 3 bandages have never been evaluated under standardized conditions.
| Results|| |
Pressures and static stiffness indexes
Before the treadmill test, the resting pressures under the bandages were not statistically different [Table 2] from each other. The variation coefficients (6.7% for Urgo K2, 7.8% for the Biflex Kit and 5.3% for SSB2) are low and close to each other. They attest to the good reproducibility of the laying technique.
|Table 2: Resting pressures, working pressures and static stiffness index before the treadmill test|
Click here to view
When standing, the pressures achieved are no different between Urgo K2 and the Biflex Kit. On the other hand, the pressure under SSB2 is statistically different from the pressures under the other 2 bandages (SSB2 vs. Urgo K2 P < 0.0001 – SSB2 vs. Biflex Kit P < 0.01).
Concerning the SSI, the differences are not statistically significant between Urgo K2 and Kit Biflex but the difference with SSB2 is very significant with the SSI of the other 2 kits (P < 0.0001).
After the treadmill test [Table 3], there was a significant decrease in resting pressures (P < 0.0001) and working pressures between SSB2 and the others (P < 0.01) but paradoxically the SSI were not significantly different from those observed before the treadmill test (P = ns). Under SSB2, the pressure drop at rest is 12.2 mmHg (32%), under Urgo K2 and Kit Biflex 8.6 mmHg (21%) and 6.4 mmHg (16%) respectively. The differences are significant (P = 0.01) between Urgo K2 and Kit Biflex and highly significant between SSB2 and the other two kits (P < 0.0001).
|Table 3: Resting pressure, working pressure and static stiffness index after treadmill test|
Click here to view
There were no differences between the results on the overall population of the study and those of the male or female group.
Comfort of the 3 different bandages before and after the treadmill test
The comfort measured by visual analogue scale with the 3 bandages is not significantly different before the test. There was an identical improvement with the 3 bandages after the test [Table 4]. The difference before and after the test is 12% (P < 0.01) and is similar for all 3 bandages.
We did not observe any significant slippage after the treadmill test for the 3 bandages applied in these subjects without edema.
| Discussion|| |
Before the treadmill test, the 3 bandages at rest were applied with similar pressures, the working pressures and the SSI then reveal a hierarchy between the 3 bandages.
From a simple point of view of the pressures achieved and the SSI, Urgo K2 and Kit Biflex appear to be generally equivalent. The resting pressures after the treadmill test remain above 30 mmHg. The Biflex kit is finally very similar to Urgo K2 with an SSI of 15 mmHg. SSB2 is a bandage with a higher SSI and significantly lower resting pressures (P < 0.001) than with the other 2 kits after the treadmill test.
Under these 3 kits, the reduction in pressure during use is a safety factor for people whose arterial condition is not always known. This pressure drop is accompanied by the maintenance of stiffness, which guarantees a significant action on the venous pump.
This drop in resting pressure is a safety element during the learning phase of bandage use where optimal pressures are rarely achieved. We are certain that the pressures under the kits will drop rapidly with a preservation of its efficacy on the venous pump.
The study of comfort with the use of 3 bandages highlights a little-known phenomenon. There is an adaptation of the subject studied to his bandage. This is contrary to what is traditionally taught. Any discomfort usually results in the removal of the bandage. Should the patient wait and walk before removing the bandage?
| Conclusions|| |
The use of a treadmill is a complementary element to study the behavior of bandages in use. This test makes it possible to compare the bandages between them and to appreciate the evolution of pressures over time. In clinical research, this test could be useful before starting the clinical phase of development in comparative clinical trials in venous leg ulcers.
It also makes it possible to anticipate their tolerance in patients at arterial risk (IPS >0.6 and <0.9 or a distal pressure >60 mmHg). In this context, are they the proof that stiff bandages are a safe management in the treatment of venous or mixed leg ulcers? Unlike long stretch bandages.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]