Transcript Final presentation template

University of Pittsburgh
Senior Design – BioE 1160/1161
Redesign of a
Safety Syringe
Jessica Chechak
Jason Keiser
Ellsworth Weatherby
April 18, 2005
Presentation Overview
• Problem Statement
• Proposed Solution
• Specific Aims
• Design Considerations
• Design Requirements
• Design Process
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•
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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
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
Proposed Solution
We propose the creation of a single use
safety syringe that includes several
categories of safer device features:
1.Retractable Needle
2.Sliding Sheath
3.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
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.
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 rapidprototyper 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
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
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
Safety Syringe Design Requirements
Our design goals were to achieve every
FDA 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
Design Process: Initial Design
• 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 Mid-December
Design Process: Final Design
• 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.
Final Design:
Before Use
Final Design: Intended Use
Before Use
After Use
Ready To
Inject
Ready For
Disposal
Design Review
Syringe Body
Protective Cap
Are the dimensions in mm?
Yes
Are the dimensions in mm?
Yes
Does the body fit into the protective shield?
Yes
Yes
Does the syringe body have a 9mm opening
for the plunger?
Yes
Does the Cap have a luer thread
pattern on the inside conforming to ISO
594-1:1986 "Female Fittings?“
Does the syringe body bottom opening have
a luer thread pattern comforming with ISO
594-1:1986 "Female Fittings"?
Yes
Does the luer threading and cap fit onto
the protective shield?
Yes
Does the body have an opening to lock-in
the push button mechanism?
Yes
Backing Pad
Protective Shield
Are the dimensions in mm?
Yes
Does the protective shield fit over the
syringe body?
Yes
Does the shield have a luer thread pattern
on the ouside end conforming to ISO 5942:1998 "Male Fittings"?
Yes
Does the shield have a square pattern on
the top for use with the push button?
Yes
Does the luer threading and shield fit into
the Protective Cap?
Yes
Are the dimensions in mm?
Yes
Does the backing pad fit against the
back of the protective shield?
Yes
After all questions
were answered “Yes”
prototyping began.
Prototype Fabrication
• The prototype was produced by quickparts.com
• 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
Prototype: Intended Use
Before Use
After Use
Ready To Inject
Ready For Disposal
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
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
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
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Ease of use
Biocompatability of components
Non-Allergenic components
Easily disposable – Biohazard safe
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
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.
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 postexposure treatment costs for by between $37million and $173
million per year.
Market size
•
550M per year (US hospital patients)
Frost & Sullivan (www.chetday.com/medmistakes.html)
Distribution
• Hospitals, Individuals
Cost Effectiveness of Safety Devices
Cost of safety devices are offset by cost of postexposure prophylaxis and follow up in medium
and high-risk scenarios
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.
Group Responsibilities
• Ellsworth: Business Manager /
Safety Coordinator
• Jason: Design Coordinator
• Jessica: Project Coordinator
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
Jason’s Achievements
• Design Coordinator:
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Modeling of design in Solidworks
Design modifications
Design Review
Prototyping
Functionality Testing
Writing Section D of the SBIR Phase I
Application
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
Any Questions?
Hypodermic syringes with
“Needle-Sheath” safety feature
• Active Safety
Feature
A feature that
requires the
operator to
activate the safety
mechanism, and
failure to do so
leaves the
operator
unprotected
“Needle-sheath” syringe
Hypodermic syringes with “Retractable
Technology” safety feature
• Passive Safety
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.
Retractable needle
safety syringe