A study of functionality of anti-embolism stockings

Abstract

The use of pressure has been understood for centuries to treat venous disorders. Antiembolism stockings (AES) represent one of the preferred modalities of pressure treatment due to their ability to prevent further complications, such as deep vein thrombosis, whilst in a hospital setting in the supine position. AES are typically mass manufactured on circular knitting machines with nylon and elastane. The scattered political and geographical influence upon medical products, test methods, test machinery, standards and Class, creates confusion over the application of AES for medical practicioners. As the world population continues to grow at a rapid rate, the need for a simplified and unified approach to medical products would prevent the incorrect use of AES and potentially remove barriers to enable increased usage of AES. The marketplace is complex, with a multitude and of brands, sizes, classes and no standard labelling or approach to pressure adherence. The hypothesis of this thesis is that a single product (one yarn and one structure) should be able to provide the British Standard pressure range of 10-18mmHg across the British Standard ankle measurement (172-288mm). The properties of three Brands; Saphena, Preventex and Ted Covidien have been fully explored and showed that different brands use different structures and yarns to create AES and therefore, subsequently exert different pressures on the body. The main test methods used in the medical world were also explored and a comparative cross laboratory study was carried out. This investigation also explored the use of 16 different structures and 6 elastane yarns and their pressure delivering capabilities. During this investigation it was found that it is possible to have one AES yarn combination of T902 285dtex and 44/34/2 Bulked Nylon which exerts the British standard acceptable pressures at the ankle (10-18mmHg) and calf (8-14mmHg) across the whole range of British Standard leg sizes at ankle 172-288mm and calf 282-446mm. It was also found that it was possible to predict the pressures on the midpoint of leg circumference to ±2mmHg which could save a significant amount of time in the development of new AES or compression products.