Scott Soong, CEO
Running a hospital efficiently and providing high-quality care relies on the right patients being in the right place at the right time and given the right treatment. Where is patient A? Is this patient B? Can we confirm what operation were performing on patient C?
With hospitals caring for hundreds or even thousands of people every day, delivering the best care to each individual represents a significant logistical challenge and while mistakes are rare, they do occur.
Minimizing Incorrect Patient Identification
Efforts have been made to minimize errors where patients are incorrectly identified and consequently receive the wrong treatment. Initiatives to use radio-frequency identification (RFID) tags, some even containing location trackers, have been rolled out in both the UK and the USA. However, despite encouraging results, take-up of this type of patient-identification and tracking technology is far from universal.
One reason, perhaps, is that information stored in RFID patient-tracking tags cannot be read without additional equipment, such as a hand-held scanner or a device that links to a centralized information system. This requirement for almost every staff member to be supplied with extra equipment adds cost for hospitals. For staff, having to use a device to obtain information they were perhaps used to being able to read in an instant makes things less convenient.
However, if such a tag incorporated an always-on display, it would provide all the benefits of RFID/location tags, while still enabling all medical staff to view critical information at a glance, without specialized equipment.
The Display Power Challenge
The challenge is how to include a display in wireless devices that must operate for long periods on a small battery, such as a CR2032 coin cell.
Thin-film transistor (TFT) liquid-crystal displays (LCDs), for years the only real option for designers wanting a thin, light display in their products, are unsuitable for devices with extremely limited power budgets, such as patient-tracking tags. A small, always-on TFT LCD would drain a CR2032 within hours.
The e-paper Solution
There is a possible solution to this conundrum: the e-paper display (EPD). This display technology rose to prominence through e-readers, where its ultra-low power usage and easy readability, even in direct sunlight, were important factors in helping e-readers achieve the success they have.
EPDs work differently from TFT LCDs. The pixels in an EPD are tiny capsules containing ink pigment, typically black and white, although red and other colors are becoming available. These capsules are sandwiched between two electrodes, the top one transparent.
Each pigment particle is electrically charged: in a black-and-white display, the black is negatively charged and the white positively. By applying a charge to the electrode above a pixel, you attract pigment with the opposing charge. To create a dark area, apply a positive charge to raise the negatively charged black particles into view. Apply a negative charge, and you’ll bring the white particles to the top and create a clear area on the display.
Crucially, once you’ve applied appropriate charges across the display and your text or image is in place, it will remain there, consuming no further power until you change whats on the display.
Moreover, because they contain physical pigment particles that reflect (or don’t reflect) ambient light, EPDs don’t require a backlight and are readable even under very bright light.
Removing the backlight and not needing to constantly refresh the display to maintain a static image as you would with a TFT LCD means a small, always-on, two-inch EPD updated six times per day will use less than 2 percent of the capacity of a CR2032 coin cell in a year.
The Ideal Display Technology for Patient Trackers
This blend of characteristics makes EPDs an ideal addition to patient-tracking tags. They could be incorporated into existing tags with minimal impact on the devices power budget and weight.
This would provide a best-of-both-worlds patient-tracking and identification solution. As with existing RFID tracking systems, a central control room would know where any patient is at any time, and authorized staff could access full medical records from the tag using a discrete device. Meanwhile, the display would enable all staff to read off selected information such as the persons name and key treatment details at any time, without relying on additional equipment.
Even if the battery ran out, the contents of the display would remain visible, meaning critical information, such as the patients name, could still be easily accessible to all staff.
Beyond Patient Tracking: Organs, Blood and Equipment
Patients aren’t the only things that move around hospitals. Blood and organs, for example, could also benefit from having a location-tracking tag with an EPD attached, so that staff could instantly confirm they have received the right item for the patient they’re caring for. Similarly, keeping tabs on all the expensive equipment in a hospital could be enhanced by having a small display built into the RFID tag on each item. This could show when it was last serviced or calibrated, to confirm its safe to use.
EPDs represent an exciting opportunity for product manufacturers to add a display to their designs, thereby helping improve healthcare services in ways that were previously not possible. Pervasive Displays offers a range of off-the-shelf EPDs and development kits that designers can use to try out the technology.
About the author
Scott is CEO of Pervasive Displays and has over a decade of experience in software in addition to 12 years working in displays businesses. During his career, Scott has been a founding partner at four start-up companies, including Pervasive Displays. Scott sits on the board of several other technology businesses as a consulting partner. He was a board member of One Laptop Per Child (OLPC), which looks to provide children in developing countries with a rugged, low-cost, low-power, connected laptop.