Medical Devices Unwired

The application of wireless technology to medical devices continues to grow as clinical applications are identified, hardware costs fall and connection reliability is improved. Today there are numerous applications of wireless technology in the medical device product space. These applications implement varied wireless configurations and operate in diverse and complex health care environments.

Wireless Adoption Drivers

The adoption of wireless in medical devices has proceeded slowly for many years. Given the life-critical nature of much of the data being transmitted, the device industry’s “go slow” approach to adoption has been prudent. The use of a wireless feature in a particular medical device is driven by the healthcare provider’s perception of the value it brings to diagnosing, treating and providing ongoing care
to patients. Adoption has been driven primarily by the following:

• The clinical value of ambulating patients early post-procedure, and the associated need to maintain monitoring while the patient is moving throughout the care continuum.

• The need to gather physiological data during rare events that generally occur during a patient’s normal daily activities.

• The need to track hospital equipment, patients and wandering elders.

• The need for efficient and time-critical access to patient data by an increasingly mobile and thinly-spread cadre of heathcare workers.

• The need to program, control and gather data from implanted devices without invasive procedures or the use of wires passing through the skin.

• The move to reduce health care cost and improve quality of life by caring for elders and those with chronic illness in their homes.

• Ease of equipment installation and use at the point of care.

Applications

These are some successful medical device applications of wireless technology, including the typical wireless technology employed and clinical data transmitted over the link.

RF Environment

As you can see the clinical applications and operating environments are diverse. Environments include hospitals, outpatient clinics, doctors’ offices, emergency vehicles and the home. Engineers contemplating developing a medical device with wireless capabilities must fully understand the implications of these environments on the RF performance of the device they are designing. In many cases proper implementation requires site surveys and extensive network testing to ensure integrity of the wireless network.

Medical Device Wireless Bands

Devices generally operate in the spectrum defined below:

Which band is chosen depends on application, competitive product positioning, RF environment, power requirements, data criticality, throughput requirements and compatibility with legacy systems. Most important of these considerations is the criticality of the data to the care of the patient. The engineer must understand the affect on patient care of delayed transmissions, lost data, roaming time, range and transmission errors. Once both criticality and the operating RF environment are understood, the best band can be chosen and an appropriate design path can be pursued.

Wireless Future

Stratos continues to be approached by innovative medical device companies that seek ways to improve patient care and delivery efficiency through the application of wireless technologies in their products. We expect this trend to continue as wireless technologies improve in their reliability and implementation costs fall. The key to success will remain a conservative and well-informed design process aimed at ensuring patient safety.