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Redesign of a Safety Syringe

Redesign of a Safety Syringe

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Redesign of a Safety Syringe

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  1. University of Pittsburgh Senior Design – BioE 1160/1161 Redesign of a Safety Syringe Jessica Chechak Jason Keiser Ellsworth Weatherby April 18, 2005

  2. Problem Statement Proposed Solution Specific Aims Design Considerations Design Requirements Design Process Initial Design Final Design Design Review Prototype Fabrication Functionality Testing Quality Systems Manufacturability Human Factors Regulatory Economic Considerations Project Timeline Group Responsibilities Ellsworth Jason Jessica Presentation Overview

  3. Problem Statement • There are approximately 236,000 percutaneous injuries resulting from accidental needlesticks every year • 50% of injuries occur between the time the procedure is completed and disposal of the device • 20% are associated with disposal of the device • Needlestick injuries expose health care workers to diseases caused by bloodborne pathogens • AIDS (from HIV) • 0.001 probability of contracting per needlestick • hepatitis B (from HBV) • 0.126 probability of contracting per needlestick • hepatitis C (from HCV) • 0.024 probability of contracting per needlestick • Adoption of needles with safety features would prevent about 69,000 needlesticks each year

  4. Proposed Solution We propose the creation of a single use safety syringe that includes several categories of safer device features: • Retractable Needle • Sliding Sheath • Screw-on cap • This novel design combines several safety features to satisfy FDA guidelines • These engineering controls effectively reduce the risk of an exposure incident in several sites

  5. Specific Aims • Modify current “safety syringe” designs to increase safety to the user as well as anyone who is exposed to the syringe. • Our proposed design contains aspects of several marketed designs, along with a few new features • Current models may have an exposed needle or a retractable needle that can leak – both are biohazards. • The combination of a retractable needle, needle shield and screw on cap will prevent needle-stick injury and leaking of biohazardous materials before and after use. • The combination of safety features will ease disposal and prevent reuse.

  6. Specific Aims • Fabricate a sufficient number of prototypes to support Phase I functionality testing. • The design was drafted in SolidWorks • The body of the syringe was produced with a rapid-prototyper thorough the process of Stereolithography (SLA). • The parts were hand-assembled by the Design Coordinator using a documented process. • Several variations of the design were prototyped to assure best fit, and to experiment with various materials

  7. Specific Aims • Test the Phase I prototypes, in vitro, to demonstrate basic functionality. • The research team used an in vitro testing apparatus to test the syringes. • Tests will show that the prototype successfully meets the functionality standards set forth by the team: • no leakage pre-use or post use • successful fluid delivery • a retractable needle

  8. Initial Design Considerations • FDA Guidelines • 29 CFR part 1910.1030, The Bloodborne Pathogens Standard • Enforced by OSHA through citations and fines • Injuries Statistics • 236,000 needlesticks/year • Every year about 1.3 million people die of blood infections caused by the re-use of syringes • Consequences of needlesticks • Disease transmission • Post-exposure prophylaxis ~ $500-$1,000 per injury • 1.7 million workers needed time off to recuperate after incidents

  9. Safety Syringe Design Requirements • Our design goals were to achieve everyFDA recommended design feature characteristic of a safer device: • Provide a barrier between the operator's hands and the needle after use • Will allow the operator's hands to remain behind the needle at all times • Be an integral component of the device, and not an accessory • Provide protection before, during and after use and after disposal • Be simple and self-evident to all operators and require little training and no particular expertise

  10. The initial design utilized a push button to retract the protective shield. This facet was redesigned to reduce the complexity of the design and to reduce the cost of mass manufacturing. The retractable needle mechanism was initially activated when the plunger reached the bottom of the syringe body. This was modified to make the retractable needle mechanism user activated. Initially the syringe was intended to be pre-filled; this modification allowed the syringe to be sold unfilled. Design Process: Initial Design Design Mid-December

  11. The protective shield was designed to allow the user to slide it up and down the syringe body without having to compress a button, thus simplifying the device. The retractable needle is activated by a spring loaded mechanism located in the luer of the needle. This system is triggered by a 5lb downward force on the plunger by the user after the medication has been delivered. The protective cap remains locked into position before and after use until a force of 1lb is applied. Design Process: Final Design Final Design: Before Use

  12. Final Design: Intended Use Ready To Inject Before Use Ready For Disposal After Use

  13. Design Review After all questions were answered “Yes” prototyping began.

  14. Prototype Fabrication • The prototype was produced by • Solidworks files of the design were used • Stereolithography (SLA) rapid prototyping was used to produce the parts • The initial prototypes were made of Somos® 14120 (a low viscosity photopolymer – white color) • Issues with tolerances and angle of threads • A second set of prototypes was made also using Somos® 14120 • Parts were assembled, fit was good, but thread angle needed to be changed • A final set of prototypes was made of Somos® 11120 (a low viscosity photopolymer – clear color) • New material had different tolerances, but we were able to combine parts to produce the final prototypes

  15. Prototype: Intended Use Before Use Ready To Inject Ready For Disposal After Use

  16. Comparison to Current Syringes:Before and After Use Our Hybrid Safety Syringe Protective Shield Safety Syringe Retractable Needle Safety Syringe Normal Syringe (Non-Safety) Before Use After Use

  17. Functionality Testing • Functionality testing was performed to demonstrate that the syringe met the standards for success: • No leakage pre-use or post use • Successful fluid delivery • A retractable needle • Operational needle shield • Operational screw-on cap

  18. Quality Systems Considerations Manufacturability • Simple Design • Needle is surgical grade stainless steel (standard size 23 gauge) • Plastic components will be made from PTFE and polypropylene • Rapid Injection Molding will be used for production of plastic components Human factors • Ease of use • Biocompatability of components • Non-Allergenic components • Easily disposable – Biohazard safe

  19. Quality Systems Considerations Regulatory • 29 CFR 1910.1830 - Bloodborne Pathogen standard • The Occupational Safety and Health Administration (OSHA) promulgates a standard to reduce occupational exposure to bloodborne pathogens through a combination of: • Engineering controls • Work practice controls • Enforcement Procedures • Show evidence of adoption of devices/engineering controls that reduce exposure • Document plan annually and any difficulties • Inspections: complaints & some scheduled inspections • OSHA does not require a specific device

  20. Quality Systems Considerations • Regulatory (cont.) • The Needlestick Safety and Prevention Act • Directed OSHA to revise the bloodborne pathogen standard: • New definitions in engineering controls • Sharps with engineering sharps injury protection • Needless systems • Annual review/update of exposure control plan • Employers are required to select safer needle devices as they become available • Involve frontline workers in device selection • maintain detailed sharps injury log • The Centers for Disease Control and Prevention estimated in March 2000 that selecting safer medical devices could prevent from 62 to 88 percent of sharps injuries in hospital settings.

  21. Economic Considerations Cost of Safety devices: • 1 to 3.5 times more than conventional devices • The increased purchase costs of using needles with safety features would be between $70 million and $352 million per year. Cost of Post-Exposure Prophylaxis: • $500 low; $1,500 moderate; $2,500 high risk • Eliminating 69,000 needlesticks per year would reduce post-exposure treatment costs for by between $37million and $173 million per year. Market size • 550M per year (US hospital patients) Frost & Sullivan ( Distribution • Hospitals, Individuals

  22. Cost Effectiveness of Safety Devices Cost of safety devices are offset by cost of post-exposure prophylaxis and follow up in medium and high-risk scenarios

  23. Projected Project Timeline This is our initial project timeline. We remained on schedule within a day or two of our initial project deadlines. We received our initial prototype earlier than expected. This gave us time for several redesigns to produce the final prototype.

  24. Group Responsibilities • Ellsworth: Business Manager / Safety Coordinator • Jason: Design Coordinator • Jessica: Project Coordinator

  25. Ellsworth’s Achievements • Business Manager • Research on Market Size… etc. • Creation of final PowerPoint presentation • Updating controlled documents • Safety Coordinator • Research on OSHA standards for “Safe Sharps” • Writing Section B of the SBIR Phase I Application

  26. Jason’s Achievements • Design Coordinator: • Modeling of design in Solidworks • Design modifications • Design Review • Prototyping • Functionality Testing • Writing Section D of the SBIR Phase I Application

  27. Jessica’s Achievements • Project Coordinator • Scheduling Team meetings • Creation of final PowerPoint presentation • Writing Sections A and C of the SBIR Phase I Application • A: Specific Aims • C: Relevant Experience / Preliminary Work / Design Review • Editing the SBIR Phase I Application • Updating Controlled Documents

  28. Any Questions?

  29. ActiveSafety Feature A feature that requires the operator to activate the safety mechanism, and failure to do so leaves the operator unprotected Hypodermic syringes with “Needle-Sheath” safety feature “Needle-sheath” syringe

  30. PassiveSafety Feature A safety feature that remains in effect before, during and after use, the operator does not need to "activate" the safety feature Integrated Safety Design The device has the safety feature included into its design and it can not be removed or inactivated. This is the preferred safety feature. Hypodermic syringes with “Retractable Technology” safety feature Retractable needle safety syringe