BOSTON SCIENTIFIC

Encore 26

Boston Scientific Corp. engages in the development, manufacture, and marketing of medical devices that are used in interventional medical specialties. As a Product Design intern, I had the opportunity to redesign the Angioplasty Inflation Device-Encore 26 for better ergonomics. It was quite challenging to design a device that requires such acute precision. Working in the medical industry made me more sensitive to design and its impact.

Team & Role

Solo Product Designer, worked under the guidance of Design Manager (Mentor). My role included:

Medical Device Design

Ergonomic Analysis

Design Research

Ideation & Brainstorming

3-D Modelling & Rendering

Prototyping

Tools

Rhino, Keyshot, 3D printer

Timeline

2 months

What is Angioplasty Inflation Device?

Balloon angioplasty is a minimally invasive, endovascular procedure that relieves narrowing and obstruction of the arteries to the muscle of the heart (coronary arteries). The inflation device is a specialized syringe used in angioplasty procedure to inflate and deflate balloon catheters. It is also used to position and place the stent.

The challenge

The Encore 26 Inflation Device is at a competitive disadvantage with its features offering, Industrial Design and Human Factors associated with it. The market demands higher quality and low-cost inflation devices are on the rise.

Encore 26 parts and controls

Holding

Less holding space. Two part casing makes a creaking sound, making it feel fragile.

Lock/Unlock

Designed for right handed use. High force required. Restricts plunger movement.

Rotating

Difficult to rotate as insufficient handle area to support thumb during rotation.

Pulling

Hook grip, smooth and slight curve of the handle enables easy pulling.

Reading

Difficult for precise measurements, poor colour contrast & heirarchy.

Competitor analysis

Studied, operated, and analyzed several other products in the same domain to understand key features and functionality already available in the market. Insights were drawn to improve the functionality, operation and ergonomics of the existing device.

Insights on product ergonomics

VISION

Pressure gauge & barrel design.

Dial Casing, shape, size & orientation

Avoid shadows form bezel.
Indicator’s orientation should be perpendicular to operator’s line of sight to reduce parallax error. The display face should be 60°- 45° inclined with the horizontal.
The area of foveal vision is limited to a solid angle of 5° about the line of central fixation, the dial size then should be around 43 mm.
The dial shape should be circular with markings arranged in the clockwise direction. The eyes travel from left to right. A circular dial would provide information with least travel distance as compared to linear scale. Also, other shapes like square or rectangle would pose visual breaks at the corners, with a circular dial continuity is perceived.

Color, contrast & font

A high contrast should be maintained between the dial face and markings.
Since some cardiologists prefer dim light for the procedure, an illuminate in the dark font or dial face should be used.
The pointer should be close to the dial face so that it doesn’t form shadows. Also, its tip should touch the main markings without overlapping.
The font size for a handheld device should lie between 24 to 28 mm. With a font height of 3.9 to 6 mm.
San-serif fonts that are easily read and identified, should be a preferred option.
The character distance depends on the font type but should be at least 5°.

Detectability, legibility & comprehensibility

Provide target zone marking.
Maintain contrast.
Consider lighting conditions.
Tactile feedback should be considered.
General movement expectation of controls:

increase: up, right, forward, clockwise

decrease: down, left, downward, counterclockwise

open: down, left, counterclockwise

close: up, right, clockwise

HAND

Release mechanism, plunger, handle design.

Grip & Force analysis

Maximum Grip Diameter

95th percentile male: 5.9 cm

5th percentile female: 4.3 cm

Metacarpal

95th percentile male: 9.5 cm

Proximal Interphalangeal Joint

95th percentile male: 2.3 cm

HOOK GRIP

The force data from the use of all digits is 24 N for 5th percentile female and 43.6 N for 5th percentile male.

SIDE PINCH

DIGIT TOUCH

TIP PINCH

PALM TOUCH

PAD PINCH

POWER GRASP

Experiments

Conducted experiments to get pressure points and contact area while operating Encore 26.

RULA Analysis

Coloured Gloves Analysis

Immersions

Visited 3 hospitals, attended one angioplasty procedure, interviewed technicians and doctors.

Insights

A technician handles the inflation device during preparation and the procedure

The device is held inverted to keep air bubbles at the bottom

Lock/unlock (pressure release) is a quick activity frequently performed

Barrel grip and easy locking/ unlocking are most essential during usage

The technician expects tactile and visual feedback as soon as the pointer drops down to vacuum

Pulling/pushing, pressure release requires an application of force, so it would be advisable to have a design that allows neutral wrist position

Ideation and brainstorming

Created concepts, and grouped them under four major heads: holding & visibility ergonomics, a new mechanism, release action, alternative for plunger rotation. Used Pugh's matrix to weigh the concepts.

Note: These are preliminary sketches, final sketches and evaluation has not been shared as per the NDA.

Prototyping and testing

Made initial mockups using thermocol and parts of existing device; final mockups were 3D printed and tested.

Final Prototype

The final prototype was built using an industry-standard 3D printer and put to test in the internal lab. It passed the stress and pressure tests and was selected to be manufactured and tested as per the health grade devices.

Note: Final designs can't be disclosed as per the NDA.

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