Development of a Medical Product –
Transition to Production

Significant medical product development challenges were presented in the development of the BD BACTEC™ FX. The product needed to overcome conflicting requirements to increase vial capacity, maintain a 25” linear wall space and integrate optimal ergonomic standards to maximize product workflow.

The solution consists of a modular stacked unit with sliding drawers on the left and right sides, separated by a central computer processing area. Each sliding drawer contains 100 sample vials. The “stacked” aspect of the configuration enables the unit to feature the smallest footprint offered in the market place relative to capacity.

Through a process of examining anthropometric standards and Human Scale factors of user demographics during the front end of development of this medical product and creating several vial-accessing configuration scenarios, the team was able to determine the stacked, drawer configuration as superior in accommodating 400 vials while maintaining a desirable ergonomic work envelope.

A significant design and development challenge was to implement a unique system of 3 colored status indicator lights on each drawer (red, yellow and green), using an indirect lighting scheme. Rather than using a more pedestrian approach of discrete indicator lights that might be hard to see from a distance, 3 large bands of colored light were created on each door that illuminate the large recessed ellipse around the medical product drawer handles. The result created a very clear set of indicators that can be seen from anywhere in the room, while highlighting the BACTEC™ FX iconic design.

The key development and product engineering challenge was to specify and configure the LED’s to create 3 large, bright, discrete washes of color, without creating a muddy effect between the color bands. This is critical since a red light or positive detection signal can mean that medical patient risk is very high. The resulting color and location of the color bands needed to be controlled in order to provide an unambiguous read as to the status of the BD BACTEC™ FX, and whether samples in each drawer yielded positive or negative results. Engineering development consideration of the number, placement, cone angle, wavelength and brightness of the LED’s was critical to the success of the implementation, as well as the color, material, shape and texture of the elliptical reflective surfaces.

Development and packaging of the agitation subsystem within the front area of each sample drawer was also particularly challenging. The medical product required a 90% duty cycle (i.e. runs 9 out of every 10 minutes, 24 hrs, 7 days per week.) and required components needed to withstand long run times, varying loads and fatigue over an expected product life of 10 years. Contrary to the natural inclination to use large, tough metal components; the development team was able to create a 25” narrow mechanical package using small parts, through concise analysis of the rotation degrees of freedom used to mechanize the system. A careful force and motion analysis also gave focus to only one necessary component needing to bear the workload – this drive link component was the only part that required a larger form factor to resist fatigue.

From a medical product users’ perspective, the product integrates numerous user interaction innovations and benefits. The development effort was informed by a multi-dimensional medical user research program that included contextual observation, human factors analysis and prototype usability validation.

Lab-based observations and interviews with medical product technicians using legacy and competitive products were conducted. The research phase informed the development team on key user needs and characteristics that would drive the development of a medical product specification. (See Appendix 2):

• Minimizing the product footprint of the system to maximize the utilization of lab floor space, shared with other instruments, work benches, materials and systems.

• Improving the product ergonomics of loading and unloading the blood specimens, particularly with regard to back and neck strain when reaching and/or bending. Previous medical products of this nature were oriented horizontally, took up significant floor space, and made loading and unloading the product cumbersome.

• Increasing salience of visual cues for identifying and differentiating detected positives from negatives to reduce error rates and speed reporting of results.

• Reducing the complexity of use and training associated with the embedded software user interface.

• Doubling the on board barcode scanning devices to place the scanners in optimal position for scanning in and out each of the 400 vials. This improves workflow and reduces misplaced vials.

Bactec also broke new ground with significant product improvements that address both usability and workflow. Integrated into the design of the product, critical results feedback is displayed in simple, unmistakable and intuitive status lights on both the inside and outside of the medical product. The integration of dynamic feedback as well as the additional user benefits outlined below led to extremely positive customer feedback during clinical trials. Specifically, the medical product consumers praised the features developed into this medical product to actually improve throughput while reducing the overall product footprint.

Visual Design and Cognitive Cues

• Each separate door/drawer in the medical product has a set of indicator lights, so product technicians can view status from across the lab. The external light ring maps to the four quadrants of the system to simply communicate overall system status for each section at a glance, even from a distance across the medical lab.

• Scanning in vials into the medical product is made simple by the integration of a ledge pocket feature. Users rest the vial against the ledge at any wrist angle that is comfortable and the scanner will read the barcode.

• Within each drawer of the medical product, easy to see and decipher internal indicators of red, yellow and green provide for rapid recognition of positive and negative sample vials. A red light indicates a positive test result which could require immediate physician intervention. Dynamic light cues effectively direct the technician to particular samples based on the context of task flow. For example, initially highlighting just positively tested samples that can be removed or retained for retesting as dictated by protocol.

• The touch screen interface combines clear icons with a quadrant display to visually map the four drawers of the BD BACTEC™ FX to four information zones, providing spatially intuitive data visualization of system status and information.

• Audio cues for the medical product are provided as a secondary confirmation and altering mechanism.

Physical Ergonomics

• The overall size of the medical product was reduced by more than 50 percent. This size reduction was driven by the medical product development team in response to customer feedback that smaller is better in crowded hospital lab environments. The preferred product configuration resulted in half the footprint of the legacy medical product.

• The twin vertical drawer approach also allowed increased vial capacity while improving the medical operators' ability to reach high and low vials.

• On-board scanners enables easy, one-handed sample login and registration Once scanned, vials may be placed by the medical tech in any open slot within the product based on user preference or reach, while maintaining tracking.

• The blood collection vials are designed for safe sample collection and transportation.

The key patient benefit of the product is the ability to quickly alert technicians to positive culture identification and communicate the results to a physician as soon as possible. Positive sample detection is automatically available by mobile phone, text messaging, beeper, email or fax to any off-site medical professional. Patients can be diagnosed faster, treated earlier and possibly recovery faster. This is critical since the medical product detects staff infection which can quickly escalate in hospital and lead to death. Market reaction to the BD BACTEC™ FX has been overwhelming positive due to the highly intuitive and obvious LED feedback system and small footprint.

During development, Becton Dickinson utilized a disciplined “phase-gate” process to accurately predict product development budget, resource requirements and launch date. Manufacturing savings were a result of the development of a smaller, more compact medical product with repeated parts. The symmetry of the 4 door/drawers and the independent feedback vials also made repeat parts possible, helping to reduce tooling costs. The modular design of the BD BACTEC™ FX system will replace two aging models of BACTEC systems and help the company reduce the number of SKUs in the BACTEC medical product line.

With real-time user feedback developed by the medical product team, technicians no longer need to spend time seeking to identify positive results within a sea of samples. Through the LED feedback displays both inside and outside of the unit, positive results can be discovered faster and through wireless communication to doctors; the cycle time of diagnosis to treatment can be reduced.

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