Pressure ulcers (PU) are one of the leading health concerns among patients living in long-term care facilities and are a common occurrence in hospitals. In the United States alone, over 2.5 million patients will suffer from pressure ulcers each year, and over 60,000 patients will die due to pressure ulcer related complications. The cost to treat pressure ulcers including hospitalization costs is also prohibitively expensive; just in the United States alone it is estimated that $9.2-15.6 Billion dollars are spent annually on pressure ulcer treatments.
Pressures ulcers are often preventable if the symptoms are detected early enough, yet the monitoring of skin integrity and pressure ulcer has always relied on a direct visual inspection, which has been shown to be unreliable especially for patients with darkly pigmented skin. As such, there is an urgent need for a handheld medical device to detect and monitor the early symptoms of pressure ulcer development.
Research conducted at the UCLA School of Nursing has shown a relationship between the presence of sub-epidermal moisture (SEM) and the formation of pressure ulcers. Prior research also has shown that this sub-epidermal moisture can be directly interrogated by measuring the dielectric properties of the tissue. This led to the design of a biomedical system for the monitoring of pressure ulcer development. This system, called the SEM Scanner, is a smart compact capacitive sensing wireless handheld system which measures SEM as a mean to detect and monitor early symptoms of pressure ulcer development. The wireless handheld unit incorporates an array of bio-compliant flexible Kapton electrodes which are excited to measure and scan the SEM in a programmable and multiplexed manner. The SEM Scanner is also wireless enabled, allowing the patient data to be wirelessly uploaded through a gateway, to a remote server, where patients skin integrity can be tracked and monitored over time.
The efficacy of this system was verified through three IRB-approved clinical trials. Combined, over 100 patients participated in these trials. In one trial, the SEM scanner was able to classify the onset of PU 1.5 days prior to the visual detection of pressure ulcer symptoms in almost 70% of those patients who ended up developing a PU.
This research will have a direct impact on improving healthcare as the SEM Scanner is currently in contract manufacturing, targeting a market release in Q3 of 2013. The SEM Scanner has already received CE certification for sale in the European Union, and is currently awaiting FDA 510(k) clearance for sale in the United States.
In the design of this SEM Scanner, fundamental research was conducted on determining the most efficient electrode geometry to interrogate the moisture present in the sub-epidermal layer of the skin. Research was also conducted in how to maximize yield for manufacturing. In particular, an end of line calibration protocol was developed to ensure that despite manufacturing tolerances, each device will perform within the target specification.
Expanding upon the success of the SEM Scanner, a next generation device was designed to provide spatial imaging of SEM. This device, called the SEM Imager utilizes a novel electrode array to maximize the spatial resolution. Instead of using concentric rings as used on the SEM scanner, the SEM Imager uses an array of hexagon pads, where each pad can be programmatically reconfigured for different electrode geometries. With this architecture, the electrode geometry is not limited to concentric rings, but can be of any arbitrary shape. The SEM Imager has been shown to positively image areas of tissue with higher moisture content in a healthy subject trial.
Both the SEM Scanner and SEM Imager will have a major, tangible impact in healthcare. The SEM Scanner, as a product, will be used in hospitals and nursing homes, providing clinicians with an evidence-based method of detecting and quantifying pressure ulcers. The SEM Imager, with its general purpose distributed architecture, provides researchers a new way of visualizing tissue health. This broadly-applicable system will allow researchers to develop new methods to characterize various health challenges that the global population currently faces today.
