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S.T.R.I.D.E. compression selection guideResolution of fibrotic tissue producing a softeningof skin.Clinical symptoms:15,21 Reduced pro-inflammatory cytokines resulting inan anti-inflammatory effect, reducing pain25,35 andpromoting wound healing Reduced oedema allows for normal shoe wear andparticipation in normal Activities of Daily Living(AoDL), improving QoL.Although the positive impact of compression use isevident throughout the literature, there areinconsistencies regarding the detailed reporting ofcompression dosage (in vitro and in vivo) and/or textilecharacteristic used to achieve stated results andinsufficient documentation of descriptive comparativeproperties of textiles tested.14,15,17,18,21,34 A review of theliterature on compression garments used for currentclinical guidelines reveals variable descriptors ofcompression dosage (mmHg versus compression classversus descriptive terms including light, moderate,firm), infrequent in vivo assessment of compressionpressure and generic mention of garment style of theproduct studied (knee high, ulcer care kit,AW).14,15,17,21,18,34 These inconsistencies and lack ofinformation limit the practical application in dailyclinical practice. As a result, the current guidelinesavailable for the use of MCS and AW provide onlyrecommendations in support of the use of compressiongarments, as summarised below, rather than actualclinical guidelines for prescribing compressiongarments:21 MCS to provide improvement of CVD symptoms(oedema, skin changes, pain, QoL) MCS to reduce recurrence of VLUs MCS (‘ulcer kits’) to improve VLU healing andreduce pain MCS for acute venous disorders and in the initialphase after greater saphenous vein treatment MCS for treatment of symptomatic post thromboticsyndrome (PTS) MCS for lymphoedema management.Without more detailed information to specificallydefine the comprehensive compression profile of thecompression products used, the clinician is led tobelieve that all compression garments matching ageneric description cited in a reference, such as‘moderate compression knee high’, ‘20 to 30mmHgknee high’ or ‘Velcro adjustable wrap applied at 20 to30mmHg’, have similar compressive effectiveness.However, advancing study about the dynamicproperties of compression textiles have producedresearch to refute this assumption.3,89,10,17,19,20,31,37–40 JOURNAL OF WOUND CAREJWC STRIDE Supplement 44pp 200x270.indd 5S . T. R . I . D . E S U P P L E M E N TThis research shows that compression dosage (mmHg)is only one of the variables that have an impact onoedema and the haemodynamic efficacy of a garment.In addition to dose, the elasticity and stiffness of thetextile has been shown to have a great impact. Thus,effective compression garment prescription requiresknowledge of both the dosage and dynamiccompression profile of the textile.COMPRESSION SCIENCEMEDICAL COMPRESSION STOCKING DOSAGECompression is defined as the pressure applied to anarea of the body by the recoil of an elastic garment, orthe tension applied when donning an adjustablegarment.1,41,42 Pressure is exerted on the limb becauseof the elasticity of the MCS and is related to theextension of the MCS.5 This compression pressure istransmitted to the underlying tissues and vessels andcan be measured and expressed in mm of mercury ofpressure (mmHg). The mmHg, measured at the ankle,is the compression ‘dosage’ and is also what is reflectedon compression garment packaging.The dosage of a compression garment is one of thefactors that determines its haemodynamic efficacy andis engineered into the MCS by the type of yarns andknitting techniques used to produce the final garmenttextile.1 Inlay yarns and body yarns are knitted togetherto produce MCS textiles, illustrated in Fig 1.1.1 Thebody yarn delivers the thickness and stiffness of thetextile, while the inlay yarn produces the compressionpressure (Fig 2).1CLINICAL PEARL Compression dosage (mmHg) is onlyone of the variables that have an impact on oedemaand the haemodynamic efficacy of a garment. Inaddition to dose, the elasticity and stiffness of thetextile has been shown to have a great impact.In vitro dosage testingThe compression dosage for MCS can be measured invitro by compression garment manufacturers using adynamometer, such as a HOSY, HATRA, or Zwickmachine.12 A section of the garment at the ankle regionof the stocking, called the B point, is secured andstretched in a transverse direction, while a softwareprogramme records the amount of resistance of thegarment to the applied force across the sizing range.38This produces a hysteresis curve (Fig 3) of the measureddosages, reflective of the mmHg of inward force on alimb at each increment within the sizing range. Forexample, a 20–30mmHg garment means that, at theankle, 20mmHg of inward force is exerted on the ankle5Downloaded from magonlinelibrary.com by 193.221.073.067 on June 28, 2019.VOL 28, NO 6, JUNE 201923/05/2019 11:51

Andrew Bezear and Cameron LawS.T.R.I.D.E. compression selection guideBodyyarnBodyyarnInlayyarnInlayyarnFig 1. Inlay yarns and body yarns are knitted together to produce medical compression stocking textilesElastic coreElasticcorePolyamidePolyamide or orcotton wrappingcottonwrappingFig 2. The body yarn delivers the thickness andstiffness of the textile, while the inlay yarn produces thecompression pressureif the girth matches the smallest circumference in thesizing range. And 30mmHg of inward force is exertedon the ankle if the girth matches the largestcircumference in the sizing range. This type oflaboratory testing is performed by reputablecompression manufacturers and provides qualitycontrols to verify the dosage specified on packaging.In vivo dosage testingCompression dosage is also measured in vivo by clinicalresearchers and by manufacturing companies of bothMCS and AW. In vivo testing measures the interfacepressure (IP), which is the pressure produced by acompression garment on the skin surface, using apressure sensor such as a Kikuhime or Picopress (Fig4).43 Recommendations regarding sensor types andplacement can be found in the 2006 ICC Consensusdocument by Partsch et al.386In vivo testing of compression IP is measured at B1,located at the medial myotendinous junction of thegastrocnemius muscle and Achilles tendon (Fig 5). B1was chosen as it was found to be the area of greatestcircumferential change with muscular activation,typically 10–15cm proximal to the medial malleolus.38Although the measurement method and location forin vivo and in vitro testing are not the same, Partschdemonstrated that the correlation between the twowas highly significant.44 It should be noted that IP isdynamic, changing with the stiffness of the textile,density of the tissues under the IP sensor, movement,change in position (supine versus sitting versusstanding), as well as change in volume (circumferenceof the limb). The dynamic nature of compression isillustrated in Fig 6, which depicts IP fluctuationsobserved with change in position and/or movement.Compression Dosage GradientMost current medical MCS are designed to providegradient compression dosages with more compressionat the ankle and progressively less moving toward thetop of the garment. A graduated compression profile isengineered to oppose the anatomic hydrostaticpressure created when the body is in the uprightposition. This graduated compression profile is createdby applying more stretch to the inlay yarn at the ankleduring knitting and then gradually decreasing thetension toward the top of the garment.It is very important to remember that the dosagereported on lower extremity compression garmentpackaging is a measure of the mmHg of pressure at theankle only, across the sizing range. At the ankle, thispoint of measure is denoted as the B measurement(Fig 7). Many manufacturers follow the German RALstandard and construct their garments so that thepercent of pressure relative to the ankle falls within astandard range. According to the RAL standard, calfdosages may vary between 50–80% of the ankleJOURNAL OF WOUND CARES . T. R . I . D . E S U P P L E M E N TVOL 28, NO 6, JUNE 2019Downloaded from magonlinelibrary.com by 193.221.073.067 on June 28, 2019.JWC STRIDE Supplement 44pp 200x270.indd 623/05/2019 11:51

S.T.R.I.D.E. compression selection guideJOURNAL OF WOUND CAREJWC STRIDE Supplement 44pp 200x270.indd 7S . T. R . I . D . E S U P P L E M E N T3025Pressure (mmHg)pressure, and thigh dosages between 20–60% of theankle pressure. 45 The European Committee forStandardization (CEN) standards dictate that thepressure profile along the leg must be 70–80% at B1and 50–80% at C and D compared with the pressureexerted at ankle level at B (Fig 7).43 This standard mustbe met for garment reimbursement in many countries.However, distribution of compression dosage as itrelates to varying oedema presentations are notspecified. Furthermore, this pressure gradient may varybetween manufacturers and/or between individualproducts from a single manufacturer.Variation in compression gradient and the impact onoedema management is an area of focused research andcompression design. Bjork presented workdemonstrating a new stiffer circular knit garmentspecifically engineered to provide graduatedcompression with more even distribution ofcompression from the metatarsal heads to the thigh.46Table 1 compares the distribution of dosage andstiffness at the foot, ankle, calf and thigh of the stiffercircular knit garment compared with traditionalcircular knit and custom flat knit garments. Theproducts were manufactured by the same companyand tested in the same way, using a Zwick machine.Although they had the same prescribed dosage,distribution of that dosage was different betweengarments, as was the stiffness which we discuss later.47In a preliminary case series, wear testing results werepositive and indicated that the stiffer circular knitgarment provided clinically efficacious levels ofcontainment in the management of chronic oedemaswhere the oedema itself was more evenly distributedalong the lower extremity.46Haemodynamic response to altered compressiongradient has also been studied. Mosti and Partsch48,49observed that ambulatory patients’ using compressingstockings that exerted higher pressures on the calf thanthe ankle showed greater efficacy in increasing thevenous ejection fraction from the leg. Therefore, theyconcluded that graduated pressure profile is notmandatory in the ambulatory patient.48,49 Limitationsstated by the authors were that the study only lookedat haemodynamic function with movement over ashort time period, not over the course of a day, andonly evaluated ambulatory patients.Couzan et al.50 conducted a randomised double-blindmulti-centre study of 401 patients with chronic venousinsufficiency (CVI) to assess the efficacy of 30mmHgprogressive compressive stockings (maximal pressure atcalf), compared with ‘degressive’ compression(traditional graduated compression profile). This trialTg α 1 mmHg/1 25,0Fig 3. Example of hysteresis curve produced when testing medicalcompression stocking dosage and used to calculate textile stiffnessin vitrodemonstrated that progressive compression stockingsare more effective than usual graduated compressionstockings in the improvement of pain and lower legsymptoms in patients with CVI. Moreover, progressivecompressive stockings were easier to apply, raising nosafety concern at three months.Fig 4. Example of a devices used to measure interfacepressure in vivo, PicoPress7Downloaded from magonlinelibrary.com by 193.221.073.067 on June 28, 2019.VOL 28, NO 6, JUNE 201923/05/2019 11:51

S.T.R.I.D.E. compression selection guideGarmentcategory,dosage andsize:Circular knit (CK) (Sheer), 30–40mmHg,mediumProfile:AveragemmHg% Gradient (%mmHg comparedwith renceRange:21.5–25.5cmGarmentcategory,dosage andsize:Stiffer circular knit (SCK), 30–40mmHg,mediumProfile:AveragemmHg% Gradient (%mmHg comparedwith nceRange:21.5–25.5cmGarmentcategory,dosage andsize:Flat knit (FK), 30-40mmHg, Custom ‘medium’ (sized for same leg as usedfor CK & SCK)Profile:AveragemmHgFootNot TestedAnkle% Gradient (%mmHg comparedwith Thigh5.3914%0.71AnkleCircumferenceRange:24cmTable 1. Comparison of three knitted compressiongarments from different compression categories. Allgarments are the same dosage and size, and all garmentswere manufactured by the same company and testedusing a Zwick machine. A commercial software programwas used to produce a hysteresis curve and calculatestiffness. (Data provided courtesy of Sigvaris Group, Inc.,US) A Circular knit garment profile, stiffer circular knitgarment profile and a flat knit garment profile8There is a need for additional research to look at theimpact of varying compression gradients and thecorresponding haemodynamic function relative tovarying oedema presentations. In particular,exploration is needed regarding which oedemapresentations are best treated by different distributionsof dosage. The distribution of compression dosageacross the garment is important information that iscurrently missing from the compression profiledescriptions on packaging, which further hindersmatching appropriate compression selection to anindividual patient presentation.Compression dosage classesIt should be noted that there is variability with regardto the categorisation of compression dosages by mmHgor class, dependent on country of origin (Fig 8). Theseinconsistencies further impair the consumer’s ability tomake an informed choice. For example, a Class IIIgarment according to the French standard is20–36mmHg, whereas Class III according to theGerman standard is 34–46mmHg. These inconsistenciesfurther challenge the application of clinical researchoutcomes between countries, further muddying thewater for researchers, clinicians and consumers alike.Dosage diminished by garment fatigueIn addition to garment dosage, garment fatigue is yetanother qualitative measure of compression efficacythat is rarely mentioned in compression studies.Compression garment manufacturers are able toimplement quality controls that test and re-testgarments’ ability to maintain the stated dosage frommorning to evening, with repeated washing anddrying, and with months of use. This is key in how thegarment will perform in managing oedema. Reputablemanufacturers will not only perform internal testingbut also use outside laboratory testing to corroborateguaranteed compression dosages over the course of aday and months of use. This becomes the basis forguaranteeing their compression pressure, typically forsix months. It is important for consumers to questionhow a garment has been tested and if dosages areguaranteed. If dosage is not guaranteed, the garmentmay not consistently deliver the therapeuticcompression level needed to manage anindividual’s oedema.CLINICAL PEARL If a patient reports that their garmentchanged over time from more difficult to very easy todon, it could be because the garment is fatigued andno longer able to deliver therapeutic dosages.JOURNAL OF WOUND CARES . T. R . I . D . E S U P P L E M E N TVOL 28, NO 6, JUNE 2019Downloaded from magonlinelibrary.com by 193.221.073.067 on June 28, 2019.JWC STRIDE Supplement 44pp 200x270.indd 823/05/2019 11:51

S.T.R.I.D.E. compression selection guideIn contrast to rigorously tested garments, lesserquality garments may have the specified dosage rightout of the box, but subsequently lose that dosage as thegarment stretches and relaxes over the course of theday or with several weeks or months of use. This iscalled garment fatigue. In a 2009 dissertation, Van deWegen-Franken40 tested garment fatigue in twelvedifferent brands. The percentage drop in pressure overeight hours of use, morning to evening, varied from7.8% up to 44.8%. These findings demonstrate thatsome garments lose their therapeutic value by the endof the day, precisely when many types of oedemasrequire robust support.Knowledge of garment fatigue is necessary to ensuretherapeutic efficacy of the stated compression dosage ongarment packaging. Availability of garment fatiguetesting ensures the consumer that the specified dosagewill be provided throughout day as well as over the sixmonth warranty. If a patient reports that their garmentchanged over time from more difficult to very easy todon, it could be because the garment is fatigued and nolonger able to deliver therapeutic dosages versus thepatient becoming more proficient at donning techniques.Adjustable wrap compression dosageLike MCS, AW currently available on the market varyby textile composition as well as application process.Studies regarding the evaluation of dynamicperformance of AW with regards to the dosage arelimited and consist largely of case studies using a singletype of AW.51 Published studies focus on investigationof a singular product line and consequently the resultscannot be taken to represent an entire product line orAW as a compression categoryLateral head ofgastrocnemiusMedial head ofgastrocnemiusPressure transducershould be placed onthe skin over this pointAchilles tendonFig 5. In vivo testing of compression interface pressureis measured at B1, at the medial myotendinous junctionof the gastrocnemius muscle and Achilles tendonCLINICAL PEARL In order to maintain medically efficaciousdosages, it is very important to replace garmentsevery six monthsSimilar to MCS, AW manufactures have developedlight and firm, ready-to-wear (RTW) and customproducts. We found no studies comparing the dynamicperformance of different textiles used to construct theAW, such as light versions compared with classic styles.Lack of information regarding the textile properties of100mmHg806040200Inelastic walkingElastic walkingLyingStandingExercisingInelastic compression in various positionsFig 6. Graphic tracing of interface pressure measurements under inelastic and elastic compression with movement.JOURNAL OF WOUND CAREJWC STRIDE Supplement 44pp 200x270.indd 9S . T. R . I . D . E S U P P L E M E N T9Downloaded from magonlinelibrary.com by 193.221.073.067 on June 28, 2019.VOL 28, NO 6, JUNE 201923/05/2019 11:51

S.T.R.I.D.E. compression selection guide(T) WaistWaistBack(K2-T)HipsHFront(K1-T)HTop of ThighGGMid-ThighFFPatellaEEBelow KneeDDCCB1B1Widest CalfBelow CalfSmallest AnkleBHeel YBase ofToesBYAAFig 7. Standard points of reference for circumferentialmeasurements for custom garments, or compressionpressure measurementsan individual AW limits consumers’ choice to evaluateits dynamic performance compared with other AWavailable on the market.Similar to the dosage calculation for MCS, AWcompression dosage is measured by the stretch of thetextile when wrapped around the limb of a knowncircumference.52 Published works focus on the visualmarkings to indicate the IP upon donning the garment.These markings provide information on the restingpressure but not the dynamic change in compressionpressure that would be created with a change in positionor movement. In addition, there have been no studieslooking at varying compression gradients with AW, suchas greater compression at the calf versus the ankle, asthey relate to haemodynamic performance or overalloedema management. One study did note that theapplication styles (interlacing versus overlapping) of theAW on the market may impact functional performance,but no objective measurements were reported.5310Dosage prescriptionKnowledge about the dosage of compression isimportant to address underlying haemodynamicresponse. It has been shown that low pressure is ableto prevent or reduce oedema and that external pressureof 20mmHg is enough to narrow or occlude the veinsin the supine position.36 However, in the uprightposition much higher pressures are required to achievehaemodynamic effects.Compression science literature demonstrates thateffective compression requires that the externalpressure applied is greater than the intravenouspressure, thereby causing a narrowing of the leg veinsand increased velocity of venous blood flow.Furthermore, a therapeutic dose of compression isdependent on position of the bod

field of medical compression therapy and will help to put the prescription of a specific product on a more rational basis. Enjoy reading! Hugo Partsch Emeritus Professor Medical University of Vienna, Austria D ear Readers, Thank you for joining us in a compression