CalfPad reduces risk factors for DVT

CM/5262/ October 2008 Length of text: 485 words

Arrow Medical builds CalfPad for Novamedix

New CalfPad™ safeguards against the risk of deep vein thrombosis

Working with Novamedix Services Ltd of Andover, Hampshire, Arrow Medical Ltd of Kington, Herefordshire has engineered the new CalfPad to help reduce the incidence of deep vein thrombosis (DVT) that may occur in patients undergoing surgical procedures. The CalfPad™, with the A-V Impulse System®, effectively reduces the principal risk factor for DVT formation by increasing venous return in the lower limbs.

The CalfPad, originally invented by two young UK surgeons, and latterly designed by Novamedix for volume production, comprises a set of air-filled inflation bladders, held in place around the calf, within a series of fabric layers. In clinical applications, a pair of CalfPads is linked to the A-V Impulse System, and then applied to the patient's lower limbs. With the special design of the bladder a targeted impulse compression is applied to the patient's calf. Commencement of therapy results in intermittent and rapid inflation of the CalfPads, initiating high velocity and turbulent venous return in the lower limbs. This mimics the physiological process of walking with full weight bearing, which is known as the "Golden Standard" of DVT prevention. By replacing the natural process of walking, CalfPad significantly reduces venous stasis, the principal factor for DVT formation. The CalfPad device can be used by patients in bed or sitting at rest. A variety of other Novamedix disposable garments are available for circulation enhancement to reduce the complications associated with immobility.

The CalfPad, produced in three sizes, required very careful design and fabric engineering to ensure that clinicians can target the regular pulses on appropriate areas of the limb. Design for production involved specialist assembly of airtight inflation bladders, encompassed in multiple layers of biocompatible fabric. These include the inflation bladders, RF welded from polyurethane, laminate PVC, unwoven polyesters, and a foam layer with a skin contact face of brushed nylon.

As part of the project Arrow Medical designed a series of RF welding techniques to produce the inflatable air bladders from medical grade polyurethane, then bond all the layers into a single piece. The production of leak-free air bladders is critical to ensure long life and operational efficiency. Here, Arrow Medical has designed a set of specialist techniques using various RF welding procedures to establish complete reliability and consistency in volume production runs.

Arrow Medical's production planners handled all aspects of production build-up, from prototyping to limited market release, with a rapid transition to full market release as soon as Novamedix acceptance trials were successfully completed. All products of this type are supported by Arrow Medical's metrology team, which carries out life and conformance tests to ensure standards are met. Over a 14-year period Arrow has worked with Novamedix to maintain standards and minimise labour and material costs within a continuous improvement programme, which includes complete product traceability back to raw material suppliers. Arrow manages labelling, logistics and stockholding and applies clinical and operating instructions to both the CalfPad and packaging for wholesale distribution and clinical centres. Arrow Medical works to global medical standards, including manufacture to ISO 9001, FDA GMP, and ISO 13485:2003.

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More information from:
John Johnson
Arrow Medical Limited
Hatton Gardens Industrial Estate
Kington
Herefordshire HR5 3RB
Tel: +44 (0)1544 231760
Fax: +44 (0)1544 231640
Website: www.arrowmedical.co.uk