TY - JOUR
AU - PhD, Heather M Powell,
AB - Abstract Pressure garments are widely employed for management of postburn scarring. Although pressure magnitude has been linked to efficacy, maintenance of uniform pressure delivery is challenging. An understanding of garment fabric properties is needed to optimize pressure delivery for the duration of garment use. To address this issue, compression vests were manufactured using two commonly used fabrics, Powernet or Dri-Tek Tricot, to achieve 10% reduction in circumference for a child-sized mannequin. Applied pressure was tracked on five anatomical sites over 23 hours, before laundering or after one and five laundering cycles. Load relaxation and fatigue of fabrics were tested before laundering or after one and five laundering cycles, and structural analysis via scanning electron microscopy was performed. Prior to laundering, pressure vests fabricated using Powernet or Dri-Tek Tricot generated a maximum pressure on the mannequin of 20 and 23 mm Hg, respectively. With both fabrics, pressure decreased during daily wear. Following five laundering cycles, Dri-Tek Tricot vests delivered a maximum of 7 vs 15 mm Hg pressure for Powernet at the same site. In cyclic tensile and load relaxation tests, exerted force correlated with fabric weave orientation with greatest force measured parallel to a fabric’s long axis. The results demonstrate that Powernet exhibited the greatest applied force with the least garment fatigue. Fabric orientation with respect to the primary direction of tension was a critical factor in pressure generation and maintenance. This study suggests that fabrication of garments using Powernet with its long axis parallel to patient’s body part circumference may enhance the magnitude and maintenance of pressure delivery. Each year over 490,000 burn injuries require medical treatment in the United States (1). Restoration of skin function to a pre-injury state for the burn patient is difficult due to the high incidence of scarring following thermal injury (2, 3). These burn scars are commonly characterized by pruritus, pain, active contracture, and erythematic appearance (3–6). As a result, these scars lead to functional and cosmetic deformities that can dramatically diminish a patient’s quality of life (2–4, 7). Pressure garment therapy (PGT) is the primary management option for the prevention and treatment of burn scars (3, 8–10). In PGT, patients wear custom-made compression garments that apply static pressure to the scar. Some studies suggest that lower pressures (15–24 mm Hg) can be effective (8, 11, 12), whereas others propose that applied pressure must exceed capillary pressure (~25 mm Hg) (12, 13). To deliver these levels of pressure to the scars, two main methods of garment fabrication are used: the Reduction Factor method and the Laplace’s Law method. The Reduction Factor method is a systematic reduction of the measured length of the patient’s body part circumference by a certain percentage, regardless of the fabric properties (3, 10, 14, 15). After the patient is carefully measured, the measurements are decreased by a standard reduction factor of 10, 15, or 20% (3, 10, 15). Generally, patient’s measurements are reduced by approximately 10% for the first set of pressure garments and by 15 or 20% for all following garments (9, 10). In contrast, the Laplace’s Law method takes into account the fabric’s tension profile in the reduction of patient measurements for compression garment construction (3, 15). Although this method provides more accurate delivery of the desired pressure magnitudes than simple reduction in circumference, it has been reported to overestimate pressure on small circumference cylinders with its accuracy varying by fabric type (16–18). Additionally, the formula assumes that each fabric exhibits only elastic mechanical behavior and does not take into consideration viscoelastic properties such as relaxation (19). A common challenge in PGT is the loss of tension within the fabric resulting in the inability of the garment to deliver the same amount of pressure with time and laundering. In only one month, garments have been reported to lose approximately 50% of their ability to apply compression due to daily wear and laundering (3, 5, 10–12). Therefore, it is necessary to replace garments after 1–3 months in order to maintain sufficient pressure (3). However, patients are also instructed to wear the garments until the scar is fully mature, which can take up to 2 years (5, 8). The high cost of garments combined with the need to replace them multiple times throughout treatment places high demands on patients. To develop garments with the most reproducible levels of applied pressure and greatest durability, it is necessary to understand how fabrics change with laundering and strain and examine why these changes occur. The current study examines two commonly used compression garment fabrics: Powernet and Dri-Tek Tricot. The Dri-Tek Tricot fabric is significantly softer than the Powernet fabric and thus is often favored by patients. However, therapists often note that they believed the pressure applied by garments fabricated using Dri-Tek Tricot was reduced vs the Powernet fabric at the same reduction factor. As a result, we sought to examine pressure beneath custom-fitted compression vests made with these fabrics in five key anatomical sites on a child-size mannequin over a period of 23 hours. Measurements were repeated after each garment underwent one laundering cycle (1 LC) and five laundering cycles (5 LCs). Fabric structure after stretch was evaluated at multiple time points to examine how the fabric may reorient itself during normal wear. In addition, relaxation and fatigue were evaluated for each fabric at three different orientation angles with respect to the axis of loading, with no laundering (0 LC), after1 LC, and after 5 LCs. Surface topography was also examined to evaluate changes in fiber texture and structure as a result of applied tension and laundering using scanning electron microscopy (SEM). Chemical analysis of the fabrics was performed in both fabrics and all laundering conditions using attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FTIR). These measurements are intended to provide a deeper understanding of fabric properties and help guide garment fabrication to manufacture garments which provide greatest clinical efficacy. METHODS Compression Garment Fabric Two fabrics widely used for compression garments were examined in this study. Powernet fabric (Darlington Fabrics, Westerly, RI) was comprised of 90% Nylon and 10% Spandex (Figure 1A). Dri-Tek Tricot fabric (Spandex House Inc., New York, NY) was comprised of 80% Nylon and 20% Spandex (Figure 1B). Figure 1. View largeDownload slide Stereovideo microscope images of 0 LC Powernet (A) and Dri-Tek Tricot (B) fabric with finished edge labeled. Scale bar = 500 μm. Figure 1. View largeDownload slide Stereovideo microscope images of 0 LC Powernet (A) and Dri-Tek Tricot (B) fabric with finished edge labeled. Scale bar = 500 μm. Laundering of Fabric and Compression Vests Fabrics and custom-made compression vests were laundered in a household washing machine with Tide® detergent (Procter and Gamble, Cincinnati, OH). Bleach and fabric softener were not used in the laundering process. Fabrics and vests underwent a normal launder cycle with cold water. To prevent heat degradation from a dryer, garments were dried flat on a drying rack following laundering. Pressure Quantification of Custom-made Compression Vests The dimensions of a child-size mannequin (Dummies Unlimited Inc., Pomona, CA) were measured using a tape measure and a 10% dimension reduction of the dummy was used for the construction of two custom-made compression vests (Shriners Hospitals for Children, Cincinnati, OH) made from Powernet fabric (Figure 2A) and Dri-Tek Tricot fabric (Figure 2B). Compression garments were placed on the dummy and pressure measurements were recorded using Kikuhime pressure sensors (Advancis Medical USA, Plainview, NY) at five key anatomical locations: 1) upper left torso or chest, 2) lower right torso or abdomen, 3) lower right torso or lateral abdomen, 4) right shoulder, and 5) upper central back (Figure 2C). The Kikuhime pressure sensors utilize air bladders that transmit surface pressure (mm Hg) readings to a digital reporting interface. Air bladders were secured at each key anatomical location on the dummy using double-sided tape and calibrated to measure a pressure of 0 mm Hg. The compression vest was then applied to the mannequin and initial pressure measurements were recorded. Pressure measurements were recorded hourly at each anatomical location for 23 consecutive hours for both Powernet and Dri-Tek Tricot compression vests. This procedure was repeated for vests made of both fabrics after 1 LC and 5 LCs to determine the effect of machine laundering on the vests ability to apply pressure. Figure 2. View largeDownload slide Child-size lifelike mannequin used to take pressure measurements of compression vests as a function of time. Mannequin wearing Powernet compression vest A. and Dri-Tek Tricot compression vest B. C. Pressure measurements were obtained at five key anatomical locations: 1) upper left torso/chest, 2) lower right torso/abdomen, 3) lower right torso/lateral abdomen, 4) right shoulder, and 5) upper central back via Kikuhime sensors. Image shows sensor secured at location 1. The Kikuhime air bladder transmits surface pressures (mmHg) to the data reporting device. Figure 2. View largeDownload slide Child-size lifelike mannequin used to take pressure measurements of compression vests as a function of time. Mannequin wearing Powernet compression vest A. and Dri-Tek Tricot compression vest B. C. Pressure measurements were obtained at five key anatomical locations: 1) upper left torso/chest, 2) lower right torso/abdomen, 3) lower right torso/lateral abdomen, 4) right shoulder, and 5) upper central back via Kikuhime sensors. Image shows sensor secured at location 1. The Kikuhime air bladder transmits surface pressures (mmHg) to the data reporting device. Mechanical Testing Load Relaxation Testing. To more directly assess the relaxation of the fabric during wear, strips of fabric (63.5 × 12.7 mm) were cut at 0°, 45°, and 90° with respect to the finished edge of the fabric for fabric in its 0 LC, and after 1 LC, and 5 LCs (Figure 1). Fabric strips (n = 3 per fabric type, per orientation and per laundering condition) were loaded into the grips of a uniaxial tensile tester (TestResources, Shakopee, MN). To mimic garment wear conditions, the grips were then set to extend the samples at a rate of 2 mm/sec until a 10% elongation (ie, a 10% garment reduction factor) was achieved and held at this level of strain for 12 hours while load was continuously recorded by MTestWr Version 1.3.6 software (TestResources, Shakopee, MN). A strain of 10% was selected as this represents the most common reduction factor (ie, 10% reduction in circumference) utilized when manufacturing the first set of patient garments (9, 10). Fabric Fatigue. To assess how the fabric properties may change with repeated stretching caused either by patient movement or repeated donning of garments, cyclic tensile testing was performed. As above, strips (63.5 × 12.7 mm) of Powernet and Dri-Tek Tricot fabric in the 0 LC, 1 LC, and 5 LCs conditions were cut from the fabric at orientations of 0º, 45º, and 90º with respect to the finished edge. Fabric samples were loaded into the grips of a uniaxial tensile tester (TestResources, Shakopee, MN) and cyclically strained to an amplitude of 10% sample length at a frequency of 0.1 Hz for 3 hours (n = 3 per fabric type/laundering condition/orientation). MTestWr Version 1.3.6 software (TestResources, Shakopee, MN) was used to record load as a function of position as the sample was cyclically strained. Overall energy dissipation was quantified by finding the area underneath the resultant hysteresis curve using the trapezoidal numerical integration function in MATLAB® (The MathWorks, Inc., Natick, MA). The more energy dissipation from a fabric, the greater the fatigue and lower the ability to maintain applied pressure. Average total energy dissipation vs the 0 LC condition ± standard error of the mean was reported for each fabric sample group. Scanning Electron Microscopy. SEM (Sirion; FEI, Hillsboro, OR) was used to characterize the effects of laundering on the fiber structure of Powernet and Dri-Tek Tricot fabrics. Samples (5.08 × 2.54 mm) of 0 LC, 1 LC, and 5 LCs Powernet and Dri-Tek Tricot fabric were mounted to aluminum stubs (Ted Pella, Reading, CA) using adhesive carbon tape and sputter-coated with gold-palladium. Samples were imaged in secondary electron mode at 5 kV accelerating voltage. Chemical Analysis of Fabrics. To investigate fabric degradation as a function of laundering, surface chemical analysis of the fabrics for 0 LC, 1 LC, and 5 LCs was performed using a Thermo Nicolet Nexus670 FTIR spectrometer (Thermo Scientific, Waltham, MA) in the ATR mode. A germanium crystal was placed in contact with each fabric sample and 25–40 scans were collected at an 8 cm−1 resolution. When infrared light shines on the cloth fibers, chemical groups in the fabric will absorb specific wavelengths of light. Any changes to the chemistry of fabric fibers can then be identified by changes in the spectra. A larger peak height indicates more of the chemical groups; a smaller peak refers to fewer chemical groups. We looked specifically at the peaks for Nylon (at Amide I [1650 cm−1], Amide II [1540 cm−1]) and Spandex (urea carbonyl [1735 cm−1]) peaks, the major constituents of these fabrics. Statistical Analyses. Statistical analyses were performed in SigmaStat v13 using One-Way ANOVA with a post hoc test of Tukey. A P-value of <.05 was considered statistically significant. RESULTS Pressure Quantification of Custom-made Compression Vests Custom-made compression vests of Powernet and Dri-Tek Tricot fabric were fit to a mannequin to quantify the magnitude of pressure supplied at five key anatomical locations as a function of time and as a result of laundering (Figure 2C). As anticipated, the applied pressure was strongly influenced by anatomic location. On the upper central back, which is slightly concave, the maximum applied pressure measured was 1 mm Hg with the majority of measurements at 0 mm Hg (Figure 3A and D). Maximum initial applied pressures observed with the 0 LC Powernet fabric were at positions 4, 1, and 3 for the right shoulder, chest, and lateral abdomen, respectively (Figure 3A). The 0 LC Dri-Tek Tricot vest applied greatest pressure at position 3 (lateral abdomen) and position 1 (chest) (Figure 3D). Hourly pressure measurements over 23 consecutive hours showed a decrease in pressure over time at areas 1–4 for both 0 LC compression vests. After 1 day, pressure applied by the Powernet vest at areas 1–4 was reduced by 22–35% from pressure measurements at t = 0 hours (Figure 3A), whereas there was a 28–50% pressure reduction in the Dri-Tek Tricot vest (Figure 3D). Figure 3. View largeDownload slide Hourly pressure measurements of Powernet (A–C) and Dri-Tek Tricot (D–F) compression vests worn by child-size lifelike mannequin (Figure 2) over the course of 23 hours for 0 LC fabric (A and D), l LC fabric (B and E), and 5 LC fabric (C and F). Pressure loss was observed in both fabric types with each successive laundering cycle, as well as a decrease in pressure over time. After five washes, the Dri-Tek Tricot compression vest displayed a marked reduction in applied pressure. Figure 3. View largeDownload slide Hourly pressure measurements of Powernet (A–C) and Dri-Tek Tricot (D–F) compression vests worn by child-size lifelike mannequin (Figure 2) over the course of 23 hours for 0 LC fabric (A and D), l LC fabric (B and E), and 5 LC fabric (C and F). Pressure loss was observed in both fabric types with each successive laundering cycle, as well as a decrease in pressure over time. After five washes, the Dri-Tek Tricot compression vest displayed a marked reduction in applied pressure. Both vests were laundered once and pressure measurements repeated at the same anatomical areas on the mannequin. Small reductions (average 2.5%) in applied pressure were observed with the Powernet vest at positions 1, 4, and 5 (Figure 3B). In contrast, applied pressure at site 3 was one third of the 0 LC (Figure 3B). After laundering the Dri-Tek Tricot vest once, applied pressure was reduced an average of 15% at positions 1, 2, 4, and 5 with an 86% reduction at position 3 (Figure 3D and E). As with the no launder condition, applied pressure decreased over time with each vest at all areas (Figure 3B and E). No additional change in applied pressure was measured at areas 3, 4, and 5 with the Powernet vest after 5 LCs compared with 1 LC (Figure 3B and C). With respect to applied pressure in the no laundering condition, Powernet fabric decreased on average 27% for all sites after 5 LCs (Figure 3A and C). After 5 LCs, the Dri-Tek Tricot fabric displayed a substantial reduction in applied pressure with garments applying only one third of the original pressure (Figure 3F). Overall, Powernet fabric was able to apply a higher amount of pressure to anatomical sites as it went through laundering cycles than Dri-Tek Tricot fabric under the same conditions. Mechanical Analysis of Fabric For each laundering group and fabric orientation, Dri-Tek Tricot fabric generated very small load at an initial strain of 10% (Figure 4D–F). This load relaxed rapidly, within 100 seconds, and continued to relax slowly for the remainder of the experiment. In contrast, the Powernet fabric generated on average 2–4 times the initial load and relaxed at a rapid pace within the first 200 seconds (Figure 4, A-C). Load decrease over the remainder of the testing but at a very slow rate. Laundering slightly reduced the average maximum load at 10% but did not significantly alter the steady-state relaxation rate for either fabric. After 5 LCs, the Powernet fabric generated more load than that of the Dri-Tek Tricot fabric at all fabric orientations (Figure 4C and F). Figure 4. View largeDownload slide Load relaxation of Powernet (A–C) and Dri-Tek Tricot (D–F) fabric at 0°, 45°, and 90° orientation stretched and held at 10% strain for 12 hours. A. and D. Fabric that has not been laundered. B. and E. Fabric that has been laundered once. C. and F. Fabric that has been laundered a total of five cycles. Overall, Powernet shows higher strength at all three orientations before being laundered and after the first wash. Powernet fabric at 0° orientation offers the highest strength compared with other options before washing as well as after a total of five washes. Figure 4. View largeDownload slide Load relaxation of Powernet (A–C) and Dri-Tek Tricot (D–F) fabric at 0°, 45°, and 90° orientation stretched and held at 10% strain for 12 hours. A. and D. Fabric that has not been laundered. B. and E. Fabric that has been laundered once. C. and F. Fabric that has been laundered a total of five cycles. Overall, Powernet shows higher strength at all three orientations before being laundered and after the first wash. Powernet fabric at 0° orientation offers the highest strength compared with other options before washing as well as after a total of five washes. Fatigue Testing Average energy dissipation calculated from cyclic testing of Powernet and Dri-Tek Tricot fabric samples were normalized to the 0 LC condition for orientations 0°, 45°, and 90° from the finished edge. For the 0° orientation and both the 1 LC and 5 LCs conditions, the energy dissipation of Powernet was significantly greater than that of Dri-Tek Tricot (Figure 5A). As laundering cycles increased from 1 LC to 5 LCs, Dri-Tek Tricot displayed a statistically significant increase in energy dissipation (Figure 5A). There was no significant change for Powernet among different laundering conditions. Figure 5. View largeDownload slide Average energy dissipation (mJ/mm2) of samples normalized to the energy dissipation at 0 washes. Fabrics were analyzed at different fabric orientations with respect to the principle axis of strain. Finished edge of fabric was oriented at 0° (A), 45° (B), and 90° (C) with respect to the principle axis of strain. Figure 5. View largeDownload slide Average energy dissipation (mJ/mm2) of samples normalized to the energy dissipation at 0 washes. Fabrics were analyzed at different fabric orientations with respect to the principle axis of strain. Finished edge of fabric was oriented at 0° (A), 45° (B), and 90° (C) with respect to the principle axis of strain. The energy dissipation of Powernet fabric with finished edge oriented 45° to the principal axis of strain showed that the decrease in normalized energy dissipation from 1 LC to 5 LCs was statistically significant (P < .05) (Figure 5B). In contrast, there was no significant difference for Dri-Tek Tricot fabric at this orientation between laundering conditions. For both fabrics in the 45° and 5 LCs condition, Dri-Tek Tricot experienced a significantly (P < .05) higher energy dissipation under cyclic loading than Powernet (Figure 5B). For both fabrics strained at a 90° orientation to the finished edge, a significant increase in energy dissipation was found for the 5 LC condition compared with the 1 LC (Figure 5C). At the same orientation, Dri-Tek Tricot exhibited a significant increase in energy dissipation as laundering increased from 1 LC to 5 LCs (Figure 5C). Powernet fabric did not exhibit a significant difference between laundering conditions, however. SEM and Chemical Analysis SEM analysis of Powernet and Dri-Tek Tricot fabric samples that for 0 LC, 1 LC, and 5 LCs conditions revealed no change in fiber structure or orientation as a result of laundering (Figure 6). Figure 6. View largeDownload slide Scanning electron microscope images of Powernet and Dri-Tek Tricot fabric at each of the laundering conditions. A–C. Powernet fabric that has underwent 0 LC (A), 1 LC (B), and 5 LC (C). D–F. Dri-Tek Tricot fabric that has underwent 0 LC (D), 1 LC (E), and 5 LC (F). No fiber structure or orientation change was found between each launder cycle for both fabrics. Figure 6. View largeDownload slide Scanning electron microscope images of Powernet and Dri-Tek Tricot fabric at each of the laundering conditions. A–C. Powernet fabric that has underwent 0 LC (A), 1 LC (B), and 5 LC (C). D–F. Dri-Tek Tricot fabric that has underwent 0 LC (D), 1 LC (E), and 5 LC (F). No fiber structure or orientation change was found between each launder cycle for both fabrics. FTIR analysis of Powernet fabric showed the presence of Nylon with absorbance peaks at 1635 cm−1 and 1535 cm−1, respectively, in all three laundering conditions (Figure 7A). Powernet fabric displayed a slight decrease in the Amide I and Amide II absorbance peaks with laundering (Figure 7). FTIR analysis of Dri-Tek Tricot fabric showed the presence of Nylon with Amide I and Amide II absorbance peaks in samples for all laundering conditions (Figure 7B). The Amide I and Amide II peaks decreased substantially in the Dri-tek Tricot fabric following laundering (Figure 7B); however, these changes were not significant above the noise within the spectrum. The FTIR spectrum for the Powernet fabric showed a distinct peak 1755 cm−1 (urea carbonyl) indicating the presence of Spandex in addition to Nylon, which was not detected in the Dri-Tek Tricot fabric. Figure 7. View largeDownload slide Fourier transform infrared spectroscopy (FTIR) absorbance spectrum for Powernet fabric (A) and Dri-Tek Tricot fabric (B). FTIR analysis showed the presence of Nylon with Amide I and Amide II absorbance peaks at 1635 cm−1and 1543 cm−1, respectively, and the presence of Spandex with urea carbonyl absorbance peaks at 1755 cm−1. Figure 7. View largeDownload slide Fourier transform infrared spectroscopy (FTIR) absorbance spectrum for Powernet fabric (A) and Dri-Tek Tricot fabric (B). FTIR analysis showed the presence of Nylon with Amide I and Amide II absorbance peaks at 1635 cm−1and 1543 cm−1, respectively, and the presence of Spandex with urea carbonyl absorbance peaks at 1755 cm−1. DISCUSSION As anticipated, magnitude of pressure delivered was a function of anatomical location. In areas where the body contour was concave, low-to-no pressure was generated as a result of little to no contact between the garment and the surface of the mannequin. Over more prominent and firmer locations, such as bony protuberances, higher pressures resulted as seen in the shoulder and chest in this study. Throughout a day’s use (23 hours), the magnitude of pressure delivered decreased as the fabric relaxed. No significant change in fabric architecture was observed following stretch to 10%; thus, it is probably that the majority of the observed fatigue is occurring at the molecular level as polymer chains within the thread fibers realign to reduce the force on each chain. The mechanical behavior of pressure garment fabrics has previously been modeled following a three element mechanical model where the fabric, under tension, initially exhibits an elastic response (an increase in length proportional to the amount of load applied) followed by a viscous response (an increase in length as the load held on the material is held constant). Following this model, when the applied load is removed, there will be both instantaneous recovery of a portion of the deformation followed by slower recovery of the full amount of deformation (19). The current mechanical tests suggest a stronger viscous component to the behavior as the fabrics were not capable of promoting full recovery after the load was removed during the time frame studied. These studies underscore the need to better understand the viscoelastic properties of these materials to enhance long-term pressure delivery. Magnitude of initial applied force and fatigue was dependent on fabric type and cycles of laundering. However, these observations were most evident in the Dri-Tek Tricot fabric. This fabric applied the least amount of pressure to the mannequin and within the tensile testing apparatus. These data are in agreement with prior studies reporting a significant increase in applied pressure when using Powernet fabric vs other common fabric types (20). In all mechanical tests, the Dri-Tek Tricot fabric was more susceptible to fatigue and to deterioration in properties following laundering. This may be due to how the two materials are blended in each fabric. Although the Dri-Tek Tricot contained 20% Spandex, 10% more than the Powernet fabric, no Spandex peaks were observed in ATR–FTIR analysis. This suggests that the two materials (Nylon and Spandex) may be in a layered composite architecture rather than a true blend. This may lead to layers within the fiber that exhibit less elasticity and resistance to fatigue. As the Nylon is the majority component, its properties may mask the fatigue properties of the Spandex. Additionally, this study observed no significant recovery of properties following laundering. In a prior study by Macintyre et al, the magnitude of pressure delivered following laundering was greater than final pressure delivered by the same garment at the end of a day’s wear (21). A possible mechanism for this discrepancy was the length of time the garment was allowed to recover between uses. In the current study, garments were tested every other day to provide time for full drying of the garment vs allowing several days for drying and “relaxation” of the garment (21). A strong dependence between properties and fabric orientation was observed in each fabric. As both fabrics are woven, changes in mechanical and structural properties with orientation were expected; however, it was not anticipated that there would be a combinatorial effect of orientation and laundering. Although the Powernet did not display significant changes in fatigue with laundering, the Dri-Tek Tricot fabric, on average, fatigued more after laundering and this increase in fatigue was most apparent when the fabric was oriented 90° to the finished edge. As the Dri-Tek Tricot fabric has a very strong weave orientation with braids of fabric oriented parallel to the finished edge, microscopic pilling of the fabric could have occurred during laundering leading to greater fatigue. The evaluations performed in the laboratory allow for a detailed analysis of the mechanical, structural, and chemical properties of the compression garment fabrics in response to “use” and laundering in a highly controlled and reproducible environment. As the addition of body heat, perspiration, and/or additional mechanical forces due to patient respiration and activity was not built into the test apparatus, it is probable that the effects of fabric fatigue would be even more pronounced under true use conditions. For example, significant reductions in magnitude of pressure delivered were observed with even slight amounts of moisture within compression garment fabrics, and this observation was dependent on fabric type with sleeknits and tubigrip fabrics most susceptible to water uptake and subsequent deterioration of properties (22). An additional limitation to the study was the anatomy of the pediatric mannequin, as the mannequin did not have arms. It is possible that the pressure readings on the chest, shoulder, and possibly the back may be greater when sleeves are attached and induce more stretching of the fabric. CONCLUSION Powernet and Dri-Tek Tricot, commonly used textiles for pressure garment fabrication, were assessed for their ability to apply load at a specific reduction factor, their fatigue properties, their structure and chemistry, and how these properties change with laundering. The data suggest that to provide garments with the least amount of fatigue, both during use and as a result of laundering, Powernet fabrics should be used in the construction of pressure garments with the leading edge of the fabric oriented parallel to the circumference of the patient’s body part. FUNDING This project was supported by the Shriners Hospital for Children Medical Research Grant (No. 85100; HMP). ACKNOWLEDGEMENTS The authors gratefully acknowledge the garment fabrication shop at the Shriners Hospitals for Children – Cincinnati for fabricating the vests for the mannequin study. REFERENCES 1. American Burn Association National Burn Repository . 2014 . Burn incidence and treatment in the US: 2014 fact sheet . http://www.ameriburn.org. 2. Goel A , Shrivastava P . Post-burn scars and scar contractures . Indian J Plast Surg 2010 ; 43 ( Suppl ): S63 – 71 . Google Scholar CrossRef Search ADS PubMed 3. Atiyeh BS , El Khatib AM , Dibo SA . Pressure garment therapy (PGT) of burn scars: evidence-based efficacy . Ann Burns Fire Disasters 2013 ; 26 : 205 – 12 . Google Scholar PubMed 4. Gauglitz GG , Korting HC , Pavicic T , Ruzicka T , Jeschke MG . Hypertrophic scarring and keloids: pathomechanisms and current and emerging treatment strategies . Mol Med 2011 ; 17 : 113 – 25 . Google Scholar CrossRef Search ADS PubMed 5. Ripper S , Renneberg B , Landmann C , Weigel G , Germann G . Adherence to pressure garment therapy in adult burn patients . Burns 2009 ; 35 : 657 – 64 . Google Scholar CrossRef Search ADS PubMed 6. Zurada JM , Kriegel D , Davis IC . Topical treatments for hypertrophic scars . J Am Acad Dermatol 2006 ; 55 : 1024 – 31 . Google Scholar CrossRef Search ADS PubMed 7. Engrav LH , Heimbach DM , Reus JL , Harnar TJ , Marvin JA . Early excision and grafting vs. nonoperative treatment of burns of indeterminant depth: a randomized prospective study . J Trauma 1983 ; 23 : 1001 – 4 . Google Scholar CrossRef Search ADS PubMed 8. Cheng JC , Evans JH , Leung KS , Clark JA , Choy TT , Leung PC . Pressure therapy in the treatment of post-burn hypertrophic scar–a critical look into its usefulness and fallacies by pressure monitoring . Burns Incl Therm Inj 1984 ; 10 : 154 – 63 . Google Scholar CrossRef Search ADS PubMed 9. Puzey G . The use of pressure garments on hypertrophic scars . J Tissue Viability 2002 ; 12 : 11 – 5 . Google Scholar CrossRef Search ADS PubMed 10. Macintyre L , Baird M . Pressure garments for use in the treatment of hypertrophic scars–a review of the problems associated with their use . Burns 2006 ; 32 : 10 – 5 . Google Scholar CrossRef Search ADS PubMed 11. Anzarut A , Olson J , Singh P , Rowe BH , Tredget EE . The effectiveness of pressure garment therapy for the prevention of abnormal scarring after burn injury: a meta-analysis . J Plast Reconstr Aesthet Surg 2009 ; 62 : 77 – 84 . Google Scholar CrossRef Search ADS PubMed 12. Staley MJ , Richard RL . Use of pressure to treat hypertrophic burn scars . Adv Wound Care . 1997 ; 10 : 44 – 6 . Google Scholar PubMed 13. Tredget EE , Nedelec B , Scott PG , Ghahary A . Hypertrophic scars, keloids, and contractures. The cellular and molecular basis for therapy . Surg Clin North Am 1997 ; 77 : 701 – 30 . Google Scholar CrossRef Search ADS PubMed 14. Wang J , Ding J , Jiao H , et al. Human hypertrophic scar-like nude mouse model: characterization of the molecular and cellular biology of the scar process . Wound Repair Regen 2011 ; 19 : 274 – 85 . Google Scholar CrossRef Search ADS PubMed 15. Macintyre L , Ferguson R . Pressure garment design tool to monitor exerted pressures . Burns 2013 ; 39 : 1073 – 82 . Google Scholar CrossRef Search ADS PubMed 16. Macintyre L , Baird M , Weedall P . The study of pressure delivery for hypertrophic scar treatment . Int J Clothing Sci Technol 2004 , 16 : 173 – 83 . Google Scholar CrossRef Search ADS 17. Macintyre L . Designing pressure garments capable of exerting specific pressures on limbs . Burns 2007 ; 33 : 579 – 86 . Google Scholar CrossRef Search ADS PubMed 18. Aghajani M , Jeddi AAA , Tehran MA . Investigating the accuracy of prediction pressure by Laplace law in pressure-garment applications . J Appl Polym Sci 2011 ; 121 : 2699 – 704 . Google Scholar CrossRef Search ADS 19. Ilska A , Kowalski K , Klonowska M , Kowalski TM . Influence of stress and relaxation characteristics of knitted fabrics on the unit pressure of compression garments supporting external treatment . Fibres Text East Eur 2014 ;22: 87 – 92 . 20. Macintyre L , Baird M . Pressure garments for use in the treatment of hypertrophic scars – an evaluation of current construction techniques in NHS hospitals . Burns . 2005 ; 31 : 11 – 4 . Google Scholar CrossRef Search ADS PubMed 21. Macintyre L , Gilmartin S , Rae M . The impact of design variables and aftercare regime on the long-term performance of pressure garments . J Burn Care Res . 2007 ; 28 : 725 – 33 . Google Scholar CrossRef Search ADS PubMed 22. Macintyre L , Dahale M , Rae M . Impact of Moisture on the Pressure Delivering Potential of Pressure Garments . J Burn Care Res . 2016 ; 37 : e365 – 73 . Google Scholar CrossRef Search ADS PubMed © American Burn Association 2018. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)
TI - Structural, Chemical, and Mechanical Properties of Pressure Garments as a Function of Simulated Use and Repeated Laundering
JF - Journal of Burn Care & Research
DO - 10.1093/jbcr/irx018
DA - 2018-02-09
UR - https://www.deepdyve.com/lp/oxford-university-press/structural-chemical-and-mechanical-properties-of-pressure-garments-as-iumVsdCmc0
SP - 1
EP - 571
VL - Advance Article
IS - 4
DP - DeepDyve
ER -