BeatBox: A Novel Device for More Realistic Pulse Simulation
Clinicians use a variety of senses to detect symptoms of disease. A critical part of the education of any clinician is the development of these sensing abilities. While clinicians have recordings to improve their ability to distinguish heart sounds and visual aids to distinguish skin spots, our client, Dr. Linda Honan of the Yale Nursing School had identified a gap during her teaching - mechanisms for developing clinicians' haptic abilities. In particular, Dr. Honan had faced difficulty teaching her students to accurately feel the pedal pulse rate and strength, an key early indicator of serious illness.
Dr. Honan tasked our student team to solve this problem.
Our team joined Dr. Honan on her rounds where we got to attempt to palpate and grade pedal pulses on real patients. Patients requiring pedal pulse palpation often also have edema in or bandages around their lower extremities. Despite these difficulties, experienced clinicians are able to make an accurate grading by palpation which showed that these haptic abilities could be developed over time.
Our team also visited the Yale Medical School's anatomy lab where we got to see a cadaver with the blood vessels in the ankle exposed for a better understanding of the anatomical markings used during palpation. Finally, we also visited the Yale Simulation Lab and got to witness state-of-the art medical simulators used to train clinicians. Most of the simulators seen had very obvious pulse mimicking technology such as actuators which gave out a sound and could be seen through the simulator skin.
Concept Generation & Selection
The most common palpation mistake is pressing too hard or too softly.
Able to notify instructor of student applied pressure
Flex sensor under 'vein' to measure sensing pressure exerted
Dr. Honan teaches in multiple rooms around the hospital and often moves with her simulators in tow.
Able to move between multiple rooms.
Portable, low-weight and wireless final device.
Diseases associated with poor pedal pulse health usually also present with low temperature skin.
Able to vary skin temperature
Diseases associated with poor pedal pulse health usually also present with cyanosis (blue skin color)
Able to vary skin color
Photochromic paint on skin allowing dynamic change.
Differentiating between different pulse rates and strengths is one of the most critical haptic skills.
Able to vary pulse strength and rate
use of low-frequency (inaudible) speaker. Vary amplitude & frequency for strength & rate variation.
Existing simulator pulses are exaggerated and loud.
Realistic i.e. as close to human as possible with no other cues.
Silicone sheet for skin feel, mimic anatomical features (bone, artery walls & distance from skin)
Speaker in background and various blood vessel height prototypes
Dr. Honan provides feedback on realism of speaker mechanism & preferred artery height
Testing photochromic paint use to display cyanosis
The Beatbox was to realistically mimic varying pulse strengths, pulse rates and skin temperature without any visual or auditory cues.
The Beatbox uses a speaker diaphragm driven by a cardiac waveform at a very low (inaudible) frequency. By controlling markers on the corresponding iPhone app, the waveform amplitude and frequency could be altered to cause variation in pulse strength and rate. The Beatbox also comprised of haptic feedback to inform the instructor on how hard each student was pressing against the pulse. The Beatbox also included Peltier tiles to vary the temperature of the surface.
Beatbox exploded view
Beatbox composite parts
1. Device presented at University of Minnesota's Student Medical Device Design Showcase (2016)
2. Device presented at Yale Tech Summit
Doshi, H., Duffy, T. C., Friedlaender, L., Honan, L., & Jenjezwa, J. (2016). Creative Collaborations with Art, Music and Engineering: Improving the Perceptual Abilities of Novice Clinician.