Medical Foam Substrates Improve Medical Device Performance and Reduce Manufacturing Costs
LAWRENCE, MA (February 3, 1997) – Cardiotronic Systems Inc. (Carlsbad, CA), a leading manufacturer of disposable electrodes for cardiac stimulation, is using medical foam substrates to improve performance and reduce manufacturing costs of its medical products. These include multi-function biomedical probes used for defibrillation, external pacing and cardioversion.
According to Jim Perrault, Director of Research and Development for Cardiotronics, the proprietary foam substrates, manufactured by Voltek (Lawrence, MA), are FDA-approved and lend themselves to a wide range of disposable medical devices. He elaborated on the properties which make foam an excellent substrate for biomedical electrodes:
Adhesive Coating: Volara provides an excellent substrate for the retention of precision adhesive coatings. Within Cardiotronics products, a perimeter type of adhesive holds components together. The foam in the disposable cardiac stimulation electrodes must adhere to both a foil and gel component. A more typical use of foam is for adhesion of the product directly to the patient’s body. This is generally referred to as foam tape. In a new Cardiotronic product design, the foam will replace white vinyl as the skin contact component.
Good Electrical Insulator: The Volara substrate serves as an electrical insulator which prevents arcing between biomedical probes. This ensures that the electrical current passes through the patient’s heart for effective electrotherapy. It also insulates the current from personnel, medical equipment, and electrical conductors such as nearby IV stands. A wide range of foam thicknesses offers the medical device designer an opportunity to select the most appropriate insulator for any application.
Tactile and Tensile Properties: Compared to a plastic substrate of similar thickness, Volara conforms better to body surfaces and provides a soft cushion that is more comfortable for the patient and less likely to cut or irritate skin. The texture of the foam provides an edge that is easier to grab when the device is being removed. Volara foam has a high strength-to-weight ratio, which makes it an excellent backing material for a disposable device.
Cosmetic Appeal and Consistency: Volara used in the design of disposable devices is uniformly clean and provided in white or tan colors appropriate for medical use. The products are guaranteed for consistency from lot to lot for high production yields.
Manufacturability: Precision coatings ensure an appropriate balance of adhesion for product integrity and ease of assembling the medical device. These products have a stiff release liner which allows for fast, clean cutting to whatever shape is needed.
Perrault says that cardiac stimulation is one of the most interesting applications of foam tape because it involves devices which are used in life-saving procedures. However, in his 17 years as a medical device designer, he has also used Volara widely in such applications as wound dressings, other types of biomedical electrodes, and transdermal drug delivery patches. He says that Voltek has established a niche in this market because of the unique thickness specifications and physical consistency of its products.
According to Perrault, “Transdermal drug delivery is probably the biggest growth area for polyolefin foam. Applications include nicotine patches, nitroglycerin patches, polymine patches for motion sickness, estrogen patches for menopause, etc. The use of foam for other medical purposes such as wound dressings or biomedical electrodes is also growing because baby boomers are maturing and the medical device market is growing as a result.”