Mobile Vital Signs Monitor Benefits from CollaborationMobile Vital Signs Monitor Benefits from Collaboration

Responding to the growing interest in remote patient-monitoring applications, Sotera Wireless (San Diego) has developed the ViSi Mobile wireless platform for continuous vital signs monitoring. Body-worn sensors comprise a wireless device that can be strapped to a patient's arm for the recording of such data as blood pressure and heart rate. A monitoring device, in turn, provides remote clinicians with access to the data being recorded in order to allow for remote patient monitoring of vital signs.

Because it would ultimately be used by patients, not clinicians, and had unique requirements, the design and development of the product presented some challenges. "When Sotera Wireless approached us with this medical device design concept, it wanted the look and feel of a small, user-friendly consumer product, but had a number of specific demands. The device had to be chemical-resistant, durable, easy-to-clean, and submersible under water," recalls Michael Swartz, growth strategist at product design company DD Studio (Carlsbad, CA). "We weren't sure the design was possible."

Helping to make the design possible, for one, was the use of Tritan copolyester MX711. Manufactured by Eastman Chemical Co. (Kingsport, TN), Tritan was employed in the product's lens, housing, printed circuit board assembly, and connectors. Offering chemical resistance and durability, the material also enabled fit and press assembly of the device along with the joining of parts without the use of chemicals, adhesives, or mechanical fasteners, according to the company.

To accommodate all of the requirements stated by Sotera, however, the product needed a material capable of withstanding water submersion for 60 minutes at a depth of 1 m. DD Studios ultimately selected the GLS Versaflex OM 3060 thermoplastic elastomer, supplied by PolyOne (Cleveland), to seal the housing and protect internal electronics. The material also adhered firmly to the Tritan substrate.

Upon completing materials selection, DD Studios approached Phillips Plastics Corp. (Hudson, WI) to evaluate design for manufacturability and develop prototype tooling. The resulting product met Sotera's initial design requirements, enabling the creation of a novel remote patient-monitoring product.