Technical Report AMI-007:
Review of 2006-2007 RERC-AMI National Student Design Competition: Accessible Infusion Pump Interface
Authors: Adam Luce
Coordinating Editor: Molly Follette Story, M.S.
Location: University of California - Berkeley
Current Version: 1.0 (August 2007)
Table of Contents
- Executive Summary
- Background
- Student Entries
- Judges' Evaluations of Designs
- Discussion
- References
- Acknowledgement
Executive Summary
This year was the fourth year of the National Student Design Competition, sponsored by the Rehabilitation Engineering Research Center on Accessible Medical Instrumentation (RERC-AMI). Over the 2006-2007 academic school year, 6 teams from 6 universities designed a prototype infusion pump interface using accessible design principles, one of three categories in the 2006-2007 competition. The devices were to be low-cost, easy to use, accessible for diverse user populations and designed to minimize use error. In this report, the prototype designs are discussed and compared, and evaluations and recommendations are provided.
Background
As science progresses, new treatments are constantly becoming available for a vast array of diseases. New treatments often bring rising medical costs, but one way to cut costs is to treat patients at home rather than in the hospital. Common medical treatments are administered through use of an infusion pump (see Figure 1) to deliver precise volumes of medication over a given amount of time. The use of infusion pumps oftentimes is a key component of treatment, and the accurate delivery of medication is crucial, as any errors could lead to detrimental effects for the patient. Current infusion pumps are often complicated, and many are not accessible to patients with disabilities such as blindness and poor motor control, which may accompany the need for medication infusion. In order for users with disabilities to safely use infusion pumps, an accessible infusion pump interface needs to be designed, one which takes into account the large array of disabilities and possibility for error. Through improved design, errors such as miscalculation of desired dosage levels, data entry error and titration error can be minimized and harm to patients avoided.
Figure 1. A modern infusion pump [1]
The Rehabilitation Engineering Research Center on Accessible Medical Instrumentation (RERC-AMI) sponsors a yearly National Student Design Competition, which provides undergraduate students the opportunity to design a product using accesible design principles. One of the 3 categories of devices for design teams to choose from this year was the accessible infusion pump interface. In this category, 6 teams from 6 different universities designed and entered a product in the competition. Teams were given a maximum design and prototype fabrication budget and funding of $2,000. In order to focus the efforts of the design teams on the capabilities of potential end users, descriptions of hypothetical clients with specific disabilities were provided (see Table 1), all of whom were described as using infusion pumps either for themselves or others. The teams then discussed how their design features addressed the needs of these clients.
The aim, specifications and clients of the competition are as follows [2]:
Aim: Design a portable, reliable, low-cost interface that is easy to use, and that works with or is built on an existing commercially available infusion pump (which may be purchased or otherwise acquired).
Specs: The infusion pump interface must communicate effectively with users (patients or care providers) through both a visual display and audio output, plus tactile cues with any user controls. Consider ease of learning and operation, aesthetics, patient privacy, information and documentation access, and storage/ loading of components. Note that any alarms must be accessible to all users.
| Client | Functional Characteristics |
|---|---|
| Mat | Blind, recent stroke |
| Akiko | Low vision |
| Jorge | Chronic back pain, hard of hearing, mild carpal tunnel syndrome |
| Lakisha | Parkinson's disease |
| Sani | Hemiparesis |
| Dolores | Deaf, severe arthritis, heart problems |
| Tyler | Hemophelia |
More information about the clients and rules for the 2006-2007 competition can be found online on the RERC-AMI website (see: http://rerc-ami.org/ami/projects/d/2/2/year4/).
Student Entries
The product table (see Table 2) compares several aspects of five of the competition entries. Due to lack of information provided, the entry from Texas A&M could not be included in the product table, evaluations or discussions.
| Product Name | Infusion Pump Interface | InfuZe Pump | Inf-U-Tech SmartFlow | Smart Medical Devices Infusion Pump | Accessible Infusion Pump Interface |
|---|---|---|---|---|---|
| University | SUNY at Binghampton |
Columbia University |
University of Rochester |
St. Louis University |
University of Connecticut |
Cost (amount spent) |
$1194 |
-- |
$1905 |
$315 |
$1208 |
| Dimensions (without pump) | 14.5" x 9.8" x 5" |
-- |
3.84" x 5.5" x 1.28" |
9.5cm x 11 cm x 6cm |
11' x 5.5" x 3" |
| Weight | -- |
-- |
-- |
500g |
-- |
| Visual Display | Yes |
Yes |
Yes |
Planned |
Yes |
| Verbal Guidance through Menus | Limited |
Yes |
Yes |
Planned |
Yes |
| Error Alarm Type | Visual, Auditory, Tactile |
-- |
Visual, Auditory, Tactile |
Planned: Visual, Auditory |
Visual, Auditory |
| Required Error Recognition (Air in Line, Low Medication Levels, Low Battery, Pressure Drops) | Yes |
-- |
Yes |
Planned |
Yes |
| Portable | Yes |
Planned |
Yes |
Yes |
Planned |
| Power Source | AC, Battery |
AC, Battery |
AC, Battery |
AC, Battery |
AC, Battery |
| Simple User Interface | Yes |
Planned |
Yes |
Yes |
Yes |
| Usable by Low Vision/Blind Patient | No |
Yes |
Yes |
Planned |
Yes |
| Usable by Patient with Limited Motor Control | Yes |
Planned |
Yes |
Planned |
Yes |
| Usable by Deaf Patient | Yes |
Yes |
Yes |
Planned |
Yes |
| Computer Required | No |
Only for prototype |
No |
-- |
Only for prototype |
| Commercial Infusion Pump Used | NE-500 |
Genie Plus |
CADD Prizm |
-- |
Baxter 6200 Flo-Gard |
Infusion Pump Interface, SUNY at Binghamton
The team from SUNY at Binghamton designed a fully-functional prototype with an easy-to-use interface and a variety of safety features. The interface is portable and separate from the infusion pump, and is connected through a cable.
In order to deal with the issue of data entry, the device has a programming mode where the healthcare provider can input all the infusion information, such as dosage detalils. The patient then only has to select one of the preset settings to receive the infusion. To enter the programming mode, the "setting" button is held down for several seconds. Simply pressing the "setting" button will bring up the preset settings for the patient to choose from.
The interface is easy to use, with seven large buttons, including four directional buttons to navigate the screens. The buttons are uniform in shape and color, which could pose a problem for users with low vision. However, there are voice prompts, though not complete guidance, to aid users with low vision. For safety features, the device has an alarm that responds to low battery, air in the line, drops in pressure and low medication levels. When an error occurs during infusion, the infusion is stopped and the user provided feedback through the LCD screen. In addition, there is verbal notification, tactile notification through vibration and further visual notification through a flashing LED. Thus the alarm system is widely accessible. Loss of connection or turning off the device will simply stop the infusion. The user has the option to resume infusion after the problem is fixed. The interface extends accessibility through its ease of use and redundant methods of notification.
A patient with limited motor control or low vision should be able to use this device, though the limited auditory assistance would exclude blind patients from use [3].
Figure 2. The Infusion Pump Interface from SUNY-Binghamton [3]
InfuZe Pump, Columbia University
InfuZe Technologies, the team from Columbia University, designed the InfuZe Pump. The pump is an early prototype, eventually intended for ambulatory use, consisting of two separate components: one mechanical and one electrical. For the mechanical aspect, the team designed an ergonomic handheld device with two easy-to-use buttons. The team would have liked to include an LCD screen and speaker, but did not have the resources or time to complete this addition. The mechanical device design is tailored especially to people with limited motor skills, as the two buttons (one under the thumb and one under the index finger) are convenient and easy to press. The mechanical prototype is non-functional, however, and the electrical component is separate and functional.
Figure 3. Mechanical component of the InfuZe Pump from Columbia University [4]
The team from Columbia University also designed a computer program, which runs on a laptop, to control the infusion pump. They simulated use of the mechanical prototype by using the same number of buttons. The user is voice-guided through the menus, making the software accessible to blind users. The software focuses on insulin treatment, and has methods to record carbohydrate intake and dictate volume of injection based on diet. The software also has a built-in tutorial to familiarize users with the program.
The design team foresees the integration of the mechanical and electrical components of the device using a microprocessor. Wireless technology could then be used to transmit information to a small, portable infusion pump for continuous infusion. Though the prototype is in an early stage, it is easy to see how this device could become marketable and extend accessibility to a large user population if the team followed through with their plans for completion. This device would be the first on the market to be fully accessible to people with diabetic retinopathy, a complication of diabetes that causes vision loss [4].
Figure 4. Redesigned commercial pump from the University of Rochester team [5]
SmartFlow, University of Rochester
The team from the University of Rochester, Inf-U-Tech, redesigned a current pump interface to be more accessible. The team greatly simplified the interface to consist of just two buttons. One button is a spinner wheel with tactile feedback for easy use, and the other is a simple on/off switch. In reference to safety, the team also kept all the built-in pumping and motor standards from the original pump. The alarm system is auditory, visual and tactile: the LCD screen shows the error message, a set of 8 LEDs flash, the interface vibrates, and the alarm is voiced through the speaker system. The device also offers optional auditory guidance through menus.
A feature unique to the Rochester device is the Radio Frequency Identification (RFID) subsystem. An RFID tag, in the form of a bracelet, is used for user identification. Using the RFID subsystem, the pump will know the user and the prescription, and deliver medication accordingly as well as maintain a dosage history. The RFID tags allow for different levels of access, so that the healthcare provider can set the prescription, including dosage rates, and the patient never needs to worry about it. To avoid errors, upon placing the RFID tag in close proximity of the device, it asks the user to confirm his or her identity. The RFID subsystem prevents use errors and simplifies the device for patients.
The Rochester team managed to include all these improvements in the handheld casing of the original pump, and produced a fully functional prototype. The voice synthesizer function navigates the menus, and in combination with the simple interface and tactile feedback buttons, extends accessibility to blind users as well as deaf users and users with poor motor control [5].
Figure 5. Prototype from St. Louis University [6]
Smart Medical Devices Infusion Pump, St. Louis University
The Smart Medical Devices Infusion Pump from St. Louis University is a partially functional prototype. The user interface is simple, and consists of only three buttons along with an LCD screen. The team planned to have audio and visual alarms and a computer program with information from the healthcare provider. The computer program works, but the team was unable to make the proper connections to transmit information from the program to the microprocessor to the pump motor. In addition, the buttons are not interfaced with the rest of the device. In order to get the pump to work, the motor must be commanded using the software provided with it in its development kit. The device is only partially enclosed by the casing, and the accuracy of the pump is far from that needed to be of use in a medical setting.
The accessibility of the final prototype is difficult to gauge, but if the planned improvements were all made, the device could potentially be accessible to blind users, deaf users, and users with low motor control [6].
Accessible Infusion Pump Interface, University of Connecticut
The team from the University of Connecticut designed an accessible interface connected to a modified pump through a bendable mounting arm. The interface consists of a large green button, a large red button, and an up-down joystick to navigate menus. These simple controls make device use much easier for all potential users. A text-to-voice converter reads out all menu items to the user, and there are many confirmation screens to avoid errors.
The device is designed for the user to set the dosage rates and other parameters, and is most likely intended for use in a home health setting. Warnings of innaccurate calculation prevent the occurrence of any lethal injection. The design is meant to fit on an IV pole with the mounting arm allowing the interface to be oriented as desired.
The team made the pump module oversized to avoid any spacing issues, but invisioned a smaller future product. The current prototype is unable to run the software using the built in drivers because of hardware issues, and the device is instead attached to a computer. The software is designed for the pump interface, however, and this problem could be simply fixed.
The auditory guidance and simple interface make this device accessible to a variety of users, including those who are blind, deaf and those with motor deficits [7].
Figure 6. User interface and pump from the University of Connecticut [7]
Judges' Evaluations of Designs
To evaluate the designs for the three categories in the competition, opinions from 10 judges from around the United States were gathered in June 2007. In this category, the University of Rochester's SmartFlow was chosen as the winner. The strengths of this device include its compact design, intuitive and clever interface, and its unique RFID subsystem. The Infusion Pump Interface from SUNY at Binghamton received the second place prize. The strengths of this design include the completeness of the prototype and the extensive safety features and alarms. The third place prize was given to the University of Connecticut's Accessible Infusion Pump Interface. This device had a simple and intuitive interface and broad accessibility.
To view all the winners of the 2006-2007 competition view: http://rerc-ami.org/ami/projects/d/2/2/year4/.
Discussion
The five projects discussed in this paper are vastly different, and all have strengths and weaknesses that future designs can draw from and improve upon. One key aspect for an accessible device is accessible instructions for new users to become familiar with the device. The team from Columbia University alluded to this aspect by including a built-in tutorial in the computer program. Instructions that are accessible to all potential users are crucial to preventing errors and misuse of the device.
Some of the teams were concerned with their pump not having all the features that are included in a commercial pump. However, the purpose of the competition was to focus on the pump interface, and the specifications and capabilities of the actual pump were not lingered over. Instead, the judges concentrated on the accessibility of the interface.
Many of the improvements made on current devices were included in multiple entries. All the teams made an effort to simplify the interface to increase accessibility. The winning team, from the University of Rochester, had a clever two-button design, including a spinner wheel and tactile feedback, greatly simplifying current interfaces in an intuitive way. The team from the University of Connecticut also had a creative interface design, with an up-down joystick and strategically placed and colored forward and back buttons. All of the teams recognized that a broadly accessible alarm system was crucial to error prevention. A couple of the teams included auditory, visual and tactile alarms to accommodate an array of users and disabilities. A few of the designs are accessible to blind users through the use of verbal guidance through all the menus.
An important aspect in error prevention is the control of data entry. The team from the University of Rochester proposed a unique solution to this problem, effectively limiting the input of prescription information to the healthcare provider. This is accomplished through the use of a computer program and Radio Frequency Identification (RFID) tags. The healthcare provider programs the RFID tag, and the user simply brings the tag into close proximity of the device and confirms their identity. The pump then reads the information from the tag, effectively preventing input errors from the patient.
Using accessible design principles, these teams have come up with unique products and solutions for this problem. Through various improvements on current devices, they have taken an esoteric technology and turned it into something intuitively usable and accessible for a diverse population of users with disabilities.
References
[1] "Product of the Month." Nottingham University Hospitals. 11 April 2006. MESU. Retrieved 13 June 2007 from <http://www.nuh.nhs.uk/qmc/MESU/Product%20Of%20The%20Month/Product%20Graseby%20500.htm>.
[2] "2006-2007 National Student Design Competition." RERC on AMI. 13 June 2007 from <http://www.rerc-ami.org/ami/projects/d/2/2/announce/index.aspx>.
[3] Infusion Pump Interface. 11 May 2007. SUNY Binghamton. Retrieved 15 June 2007 from <http://bingweb.binghamton.edu/~jhuang5/>.
[4] InfuZe Technologies. Columbia University. Retrieved 15 June 2007 from <http://www.columbia.edu/~pd2117/>.
[5] Inf-U-Tech: Home Infustion Technology. University of Rochester. Retrieved 15 June 2007 from <http://mail.rochester.edu/~mau/RERC/Index.html>.
[6] Smart Medical Devices Infusion Pump. St. Louis University. Retrieved 15 June 2007 from <http://165.134.24.22/~pump/>.
[7] Accessible Infusion Pump User-Interface. University of Connecticut. Retrieved 15 June 2007 from <http://www.bme.uconn.edu/sendes/Spring07/Team2/index.htm>.
Acknowledgment
This work is supported by the Rehabilitation Engineering Research Center on Accessible Medical Instrumentation, funded by the National Institute on Disability and Rehabilitation Research, U.S. Department of Education Grant #H133E020729. All opinions are those of the authors.