(WHS-P41) GRADIENT SKIN BARRIER RESPONSE CAUSED BY ACUTE INJURY IN A CLINICAL SKIN STRIPPING MODEL - IMPLICATIONS FOR WITHIN-SUBJECT STUDY DESIGN
Friday, May 17, 2024
7:30 AM – 5:00 PM East Coast USA Time
BACKGROUND. Transepidermal water loss (TEWL) is an indicator of skin barrier disruption following skin stripping injury. Consequently, TEWL is routinely used to assess skin response to candidate ostomy barrier formulations, with low TEWL readings suggesting that a barrier formulation is gentle on the skin when removed. When utilizing TEWL, however, studies have failed to account for potential differences, or interactions between anatomical sites on the abdomen. This study sought to determine whether TEWL response to repeated mechanical stripping was equivalent at different distances from the abdominal midline & across bilaterally symmetrical sites on the abdomens of healthy volunteers. METHODS. Following acclimation in an environmentally-controlled room & measurement of baseline TEWL at each site, a coupon of an aggressive hydrocolloid adhesive A was applied to site 1 (S1) & 3 coupons of a gentle hydrocolloid adhesive B were applied to a row of 3 sites (S2, S4, S5, right to left) across the abdomen of 50 healthy subjects . A midline untreated site (S3) served as a control. This arrangement of sites permitted comparison of bilaterally symmetrical treatments to adjacent treatments to detect anatomical effects on TEWL in response to injury. Seven cycles of adhesive application & removal after 45min were performed. TEWL readings were measured at the 5 sites after the 6th & 7th removals. RESULTS. After the 7th removal, the mean TEWL value for S1 was significantly higher (p < 0.05) than the other 4 sites, which was expected as this site was exposed to aggressive adhesive. The mean TEWL values for S4 & S5 on the opposite side of the abdomen were not statistically different, demonstrating that distance from vertical midline did not have an impact on TEWL when the formulations were equivalent. Interestingly, the mean TEWL value at S2 (gentler adhesive) was significantly higher than the bilaterally symmetrical S4 site (p < 0.05), despite being the same formulation & their equal distances from the midline. Distance from the site treated with the aggressive formulation A at S1 was the only identified difference between S2 & S4, suggesting that proximity to the injury caused by the aggressive formulation led to a gradient of greater TEWL in the adjacent sites treated with the gentler formulation. CONCLUSIONS. Addressing the study’s hypothesis of bilaterally symmetrical injury responses was not possible, due to the finding that proximity to the injury caused by an aggressive barrier formulation influenced nearby TEWL readings, revealing that acute skin stripping injuries cause skin barrier disruption that extends beyond the point of injury. Further research is needed identify the cause of this gradient effect & the implication of this effect on study designs comparing adhesives within an individual subject.