Thomas S, Young S
Medical Device Consultant, Medetec, Cardiff, UK.
J Wound Care. 2008 Jul;17(7):309-15. doi: 10.12968/jowc.2008.17.7.30524.
To investigate the fluid-handling mechanisms of film-backed foam dressings.
The fluid-handling properties of two dressings (ActivHeal Foam Island, Advanced Medical Solutions, and Allevyn Adhesive, Smith & Nephew) were compared using a standard laboratory technique, which provided comparative data on the dressings' absorbency and moisture vapour transmission. Movement of exudate through one of the dressings was also investigated in vivo using ultrasound. The fluid-handling data obtained in the laboratory were compared with exudate rates for various wound types reported in the literature to predict wear times for above products.
Absorbencies of the two dressings were broadly comparable. After 24 hours, under the test conditions, ActivHeal retained a mean of 3.44 g (SD 0.04) of the test solution and Allevyn Adhesive 4.32 g (SD 0.04), but a major difference was detected in the permeability of the two products: 12.35 g (SD 0.42) of the test solution evaporated through the back of Allevyn over 24 hours compared with 1.67 g (SD 0.11) through ActivHeal (p<0.0001). The results of the preliminary ultrasound study suggest that, in the clinical situation, exudate migrates away from the wound surface and accumulates beneath the outer film.
The difference in fluid-handling properties of the two dressings was due to the presence in one of an 'intelligent' polyurethane film component, the permeability of which varied in response to the presence of liquid. The data suggested that the film's permeability was such that the product might be expected to cope with even the most heavily exuding wounds for an extended period, but this performance would be influenced in vivo by factors such as the size of the dressing relative to the wound, and local environmental conditions, which would affect moisture vapour transmission. The somewhat unexpected finding that fluid tended to accumulate beneath the outer film during clinical use suggested the possibility of an 'osmotic pump' effect.
研究薄膜背衬泡沫敷料的液体处理机制。
使用标准实验室技术比较两种敷料（ActivHeal泡沫岛敷料，高级医疗解决方案公司生产；以及爱立敷粘性敷料，施乐辉公司生产）的液体处理特性，该技术提供了关于敷料吸收性和水汽透过率的比较数据。还使用超声在体内研究了渗出液通过其中一种敷料的移动情况。将实验室获得的液体处理数据与文献中报道的各种伤口类型的渗出液速率进行比较，以预测上述产品的使用时间。
两种敷料的吸收性大致相当。在测试条件下，24小时后，ActivHeal平均保留了3.44克（标准差0.04）测试溶液，爱立敷粘性敷料保留了4.32克（标准差0.04），但检测到两种产品的渗透性存在重大差异：24小时内有12.35克（标准差0.42）测试溶液通过爱立敷的背面蒸发，而通过ActivHeal的为1.67克（标准差0.ll）（p<0.0001）。初步超声研究结果表明，在临床情况下，渗出液从伤口表面迁移并积聚在外膜下方。
两种敷料液体处理特性的差异是由于其中一种含有“智能”聚氨酯薄膜成分，其渗透性会因液体的存在而变化。数据表明，该薄膜的渗透性使得该产品有望长时间应对即使是渗出最严重的伤口，但这种性能在体内会受到诸如敷料相对于伤口的大小以及局部环境条件等因素的影响，这些因素会影响水汽透过率。临床使用期间液体倾向于积聚在外膜下方这一有些出乎意料的发现提示了“渗透泵”效应的可能性。
