Moisture vapor transmission rates of various transparent dressings at different temperatures and humidities

Background Transparent dressings are commonly used to cover central venous catheter sites. However, it has been suggested that they might not allow adequate moisture vapor transmission, resulting in local moistness that promotes bacterial growth. We compared the moisture vapor transmission rates （MVTRs） of different, currently used transparent and traditional gauze dressings. We aimed to determine the MVTRs at different temperatures and humidities. Methods The dressings were used to seal 50-ml plastic centrifuge tubes containing 20 ml deionized water： Tubes in group 1 were covered with 12 layers of ordinary gauze, group 2 with IV3000, group 3 with OPSITE FLEXlGRID, group 4 with 3M HP Tegaderm, and group 5 with 3M Tegaderm. The tubes were placed upright in an artificial climate cabinet, so that the dressings were not touching the water, in order to simulate the conditions of medical dressings in contact with the skin. The average MVTRs were determined under different conditions. MVTRs were also determined with tubes from groups 2-5 laid on their sides, allowing the dressings to touch the water, so simulating contact of the dressings with sweating skin, or wounded skin with exudates. We also calculated the dressings＇ self-reactive abilities by comparing their MVTRs in contact with the water surface with those when not in contact with the water surface. Results Group 1 demonstrated the highest MVTR, followed by groups 2, 4, 3 and 5 under conditions simulating contact of the dressings with normal skin at the following temperatures and humidities： 20℃/30%, 20℃/60%, 20℃/90%, 37℃/30%, 37℃/60% and 37℃/90%. When the relative humidity （RH） increased, the MVTRs decreased. The MVTRs differed significantly among different dressings and RHs： At high temperature （37℃） and high humidity （90%）, the MVTR of the transparent dressings in group 2 was higher than that of group 1 （P 〈0.01）. The reactive MVTR was highest in group 2 （10.2-16.3 times 〉MVTR） while that of group 4 was second highest （2.6-9.6 times 〉MVTR）. Conclusions RH and temperature had significant effects on the MVTRs of different dressings. The IV3000 transparent dressing used in group 2 was as effective as ordinary gauze. These results suggest that increased infection rates due to low MVTRs might not be a problem. The clinical implications of these observations for catheter-related infections need to be further investigated in multicenter studies.

关于高潮气通透率的实验分析

目的通过对常用透明敷贴及传统纱布进行潮气通透性实验,观察不同温度、湿度下贴膜的潮气通透率。方法取50mL塑料离心管装20mL去离子水,选用五种医用敷料不与去离子水接触;四种医用敷料与含水表面接触,置于20℃及37℃的Rxz型智能人工气候箱中24h,设定湿度分别为30%、60%、90%,实验前后称取离心管的重量,计算潮气通透率(MTR)。结果模拟与正常皮肤接触,不同温度、湿度下,实验1组的潮气通透性最高;模拟与出汗或渗液的创面皮肤接触,不同湿度、温度下,实验2组的潮气通透性最佳;在高温37℃、高湿90%时,实验2组潮气通透率明显优于实验1组。结论温湿度对各组敷料的潮气通透性有较大影响,实验1组的透气、透湿性能为最佳,实验2组贴膜的潮气通透率与实验1组较为接近,属于高潮气通透率的贴膜,在高温37℃、高湿90%时,实验2组的贴膜为最佳选择。

关于高潮气通透率的实验研究

目的:通过对透明敷贴与普通纱布潮气通透性的实验研究,寻求高潮气通透率贴膜。方法:选用普通纱布及四种不同型号透明敷贴模拟与正常皮肤接触,以及四种贴膜模拟与出汗或渗液的创面皮肤接触,计算潮气通透率(MTR)及贴膜自身反应性潮气通透率。结果:普通纱布潮气通透性最佳,各组比较统计学有显著差异(P<0.01);在高温高湿时,实验2组贴膜的潮气通透率优于普通纱布,差异显著(P<0.01)。贴膜自身反应性潮气通透率实验2组最佳。结论:湿度及温度对潮气通透性影响较大,实验2组贴膜属于高潮气通透率贴膜。

加工工艺条件对PET/PEN共混瓶性能的影响

对聚对苯二甲酸乙二醇酯/聚2,6-萘二甲酸乙二醇酯(PET/PEN)共混复合瓶坯的成型温度和时间对瓶子表观和微观结构的影响进行了研究。使用扫描电镜、质子核磁共振(1 H-NMR)和透光率测定仪等方法,对PET/PEN共混复合瓶的微观结构、酯交换率和透明度进行了表征。结果表明,在300℃下,PET和PEN共混熔融时间为180s,制得的PET/PEN共混复合瓶具有很好的透明度;并且,其水蒸气透过量较PET瓶降低了19.1%,阻湿性优于食用油常用的PET瓶。

两种高潮气通透率透明贴膜在中心静脉置管中的作用

目的评价两种高潮气通透率透明贴膜在临床中心静脉置管中的作用。方法选择住院行锁骨下中心静脉置管(CVC)的患者334例,随机分成试验1组112例,使用透明贴膜为英国施乐辉IV3000透明贴膜留置14d;试验2组110例,使用3M中国有限公司生产的3M HP TegadermTM留置14d;对照组112例,使用3M Tegader-mTM留置时间为1d;3组留置导管均于1个月拔管,拔管后无菌剪取导管头端2～3cm行细菌培养及药敏试验,观察其导管相关感染率;更换敷料时以秒表计算每次更换时间,评估护理工作量。结果试验1组与2组及对照组感染发生率分别为0.9%、6.4%和7.1%,差异有统计学意义(P<0.05);试验1、2组透明贴膜<1月平均更换次数为(2.04±0.85)、(2.08±0.76)次,对照组透明贴膜30次,差异均有统计学意义(P<0.01);透明贴膜1月内平均更换总时间,试验组1、2组分别为(414.5±20.8)、(418.7±23.2)s,差异无统计学意义,但与对照组的(5970±230.6)s比较,差异均有统计学意义(P<0.01)。结论高潮气通透率的透明贴膜,在中心静脉置管中的应用,降低了导管医院感染的发生率,节约了护理时间,值得在临床进一步推广。