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Q: Syringes that prevent injury ( Answered 5 out of 5 stars,   0 Comments )
Subject: Syringes that prevent injury
Category: Health > Medicine
Asked by: jess05-ga
List Price: $25.00
Posted: 01 Jun 2006 14:29 PDT
Expires: 01 Jul 2006 14:29 PDT
Question ID: 734519
I am trying to understand how safety syringes work. These types of
syringes are used to prevent nurses from sticking themselves with
contaminated needles. I have been able to find that there are several
different types of safety syringes such as the ones listed below.

1) Re-sheathing needles (also called sheathing syringes)
2) Hinged needle covers
3) Sliding needle covers
4) Spring retractable needles

Can someone help me find information on how each of these safety
mechanisms work and how they may fail? I would like information on all
4 types, but if you are not able to find all 4, please post a
clarification to let me know what is possible.

I have already found a website with some information
( but need some more detail to really understand how
these work.
Subject: Re: Syringes that prevent injury
Answered By: crabcakes-ga on 02 Jun 2006 00:08 PDT
Rated:5 out of 5 stars
Hello Jess05,

    ?What Devices Are Involved in Percutaneous Injuries? 
Although many types of sharps injure healthcare personnel, aggregate
data from NaSH indicates that six devices are responsible for nearly
eighty percent of all injuries (Figure 4).  These are:
?	Disposable syringes (32%) 
?	Suture needles (19%) 
?	Winged steel needles (12%) 
?	Scalpel blades (7%) 
?	Intravenous (IV) catheter stylets (6%) 
?	Phlebotomy needles (3%) 
Overall, hollow-bore needles are responsible for 59% of all sharps
injuries in NaSH.?

?Alternatives to Using Needles. Healthcare organizations can eliminate
or reduce needle use in several ways. The majority (~70%) of U.S.
hospitals (70) have eliminated unnecessary use of needles through the
implementation of IV delivery systems that do not require (and in some
instances do not permit) needle access. (Some consider this a form of
engineering control described below.) This strategy has largely
removed needles attached to IV tubing, such as that for intermittent
("piggy-back") infusion, and other needles used to connect and access
parts of the IV delivery system. Such systems have demonstrated
considerable success in reducing IV-related sharps injuries (71-73).

Other important strategies for eliminating or reducing needle use include: 
?	Using alternate routes for medication delivery and vaccination when
available and safe for patient care, and
?	Reviewing specimen collection systems to identify opportunities to
consolidate and eliminate unnecessary punctures, a strategy that is
good for both patients and healthcare personnel.
Engineering Controls. Engineering controls remove or isolate a hazard
in the workplace. In the context of sharps injury prevention,
engineering controls include sharps disposal containers and needles
and other sharps devices with an integrated engineered sharps injury
prevention feature. The emphasis on engineering controls has led to
the development of many types of devices with engineered sharps injury
prevention features (74-78) and there are suggested criteria for the
design and performance of such devices (52). These criteria propose
that the safety feature should accomplish the following:
?	Provide a rigid cover that allows the hands to remain behind the needle, 
?	Ensure that the safety feature is in effect before disassembly and
remains in effect after disposal,
?	Be an integral part of the device, 
?	Be simple and obvious in operation, and 
?	Be cost effective. 

Moreover, features designed to protect healthcare personnel should not
compromise patient care (79).
Relatively few studies are published that systematically assess the
effectiveness of safety devices in reducing percutaneous injuries
(other than those involving needle-free IV systems), despite the
proliferation of these devices (Table 3). Reports that are available
show considerable variation in study methodology, measurement of
outcomes, and efficacy. Also, there are apparent differences in
efficacy by type of device.?
Near the bottom of the page is a chart comparing various system?s safety.

Safety Needles, in general:

This site has pictures and short videos on how the safety needles work:

Types of safety devices

Notice Picture 2 in this article. The butterfly needle is extremely
close to the finger, which  allows a health care worker to get stuck
should the patient flinch or move. (It has happened to me!)

Some safety devices:

?The terms used, often interchangeably, to describe syringes with a
mechanism that can prevent reuse and/or makes the needle safe after
use include:
?	safety syringe;
?	safer technology syringes;
?	single use syringes; and
?	difficult to reuse syringe (DTRU).
The devices available differ in operation, some 'auto-disable' i.e.
when the plunger is fully depressed, in some cases the design allows
the user to sabotage the auto-disable function by removing the
components that trigger it.
Others require user activation to disable the syringe. There have also
been suggestions of developing 'self-blunting' needles to discourage
re use.?
?Characteristics of an unsafe syringe:
A syringe which locks or is passively disabled after a single use or
can be accidentally disabled; and
A "non-reusable" syringe which is rendered non-reusable in any way that:
. does not permit full aspiration
. obscures visibility of contents of the syringe barrel
. makes the plunger move with difficulty
. means that the syringe barrel is thick to the point at which angle
of injection is inhibited
. would result in the loss of syringe contents in the event of a syringe failure.?

?No one safety device is ideal for every facility; each individual ASC
needs to determine what will work for them on a case-by-case basis.
?You need to have a multidisciplinary team that comes together, and
that?s not just executive management or purchasing,? Giarrizzo-Wilson
suggests. ?You need to have the front-line clinical folks who will be
working with those devices. That?s not just nurses and technicians;
that means docs, anesthesiologists, or anybody else involved in
patient care that is going to be using those instruments and

?They need to look at it and see if it?s appropriate. AORN doesn?t
make recommendations on specific products, but we do have guidelines
in a guidance statement that is new this year. It will be in the 2005
standards manual, and it?s a guidance statement on sharps injury
prevention in the perioperative setting.? The guidance statement is
available at
?The important thing is that the user does not have to come in contact
with the sharp,? she elaborates. ?If it?s a needle, I?ve seen the
hinged protective sheaths, where you take the syringe with the needle
on it and press down on this hinging sheath and it automatically
covers the needle. There are some, if you pull back on the plunger on
the syringe, it retracts the needle into the barrel, so you don?t have
to touch it that way. What?s really neat these days are the scalpels,
the reusable scalpel handle systems, and that?s only been in the last
year or two.

?There have been some problems; there are some designs out there that
look like a traditional scalpel blade, with a sheath that slides over,
but the problem with that is that some of the mechanisms only allow a
right-handed manipulation, so if you have a left-handed surgeon, they
either need to adapt or find an alternative. So when a person?s
evaluating the device, they need to make sure it?s going to not only
work for them, but also for their coworkers.??

?The Unitract syringe follows the same injection steps as normal
injection. You draw back on the plunger, you aspirate the syringe to
expel any excess air, you inject. The Unitract syringe has several
unique features ? one of them being, is that upon the injection stroke
you can no longer draw back on the plunger which means that you have
eliminated the reloading of the syringe therefore eliminating certain
problems with certain user groups. At the end of the injection cycle
when the plunger reaches the bottom of the syringe, it automatically
and without using any onus on the operator, retracts the needle back
into the body of the syringe and then locks the plunger out so the
plunger can now no longer move forward or backwards, so therefore we
have totally eliminated the reuse of the syringe. One other unique
feature is that the rate of retraction can be controlled by the
operator, therefore the needle can be withdrawn directly from the
human body therefore it is never exposed again.

BLANCH : There are other retractable syringes that are getting into
the market, so what makes your syringe different to those?

THORLEY : The Unitract syringe is the truly automatic retractable
syringe. The majority of the other retractable syringes in play in the
world at the moment require the operator to perform a secondary task
and, by requiring the operator to perform a secondary task there is an
opportunity that task might not be completed, therefore we still have
a dangerous sharps either lying in an accident emergency ward or lying
on the street, so that is relying on the operator to perform that
task. The Unitract syringe does not rely on the operator, it does it
fully automatically.

BLANCH : Well, it?s said that 1.3 million people die each year from
unsafe injection practices and then there are nurses like your mother
and medical practitioners, diabetics who inject insulin, intravenous
drug users and humanitarian agencies who can benefit from this device?

Hinged Needle Covers

The one handed system:
?The Terumo safety needle guarantees permanent protection with one
single-handed movement.

The Surguard needles are equipped with a unique needle locking
mechanism, which is placed at the side of the needle so it will not
block the puncture site. The safety mechanism can be activated
single-handedly : Just click the protective cover over the needle by
pressing it on a hard surface.? There is an illustration as to how it
works on this page also.

Illustration of a hinged needle cover:

?A hinged shield cover is attached to the wing just below the needle-to-wing
junction. The shield cover can be turned 180 degrees on the hinge. As the
needle is removed from the patient?s vessel, the user?s finger actively pushes
the shield cover until it latches onto needle using a one- or two- handed
technique. The shield cover is designed to allow- the user?s finger to remain
behind the needle point so that the risk of needle stick injury is minimized.
The shield cover is transparent for easy confirmation of the needle held in it.?

?The needles adopted by TEGH have safety covers that are hinged so
that once the collection or injection is complete, the cap can be
activated using only one hand. Although requiring a change in
technique to add the locking step, it is only a minimal change and "it
didn't take long for the nurses to see that safety engineered needles
work very well," says Heather McDougall, triage clinic nurse at TEGH.
"Once they realized that this was fast and easy and, most importantly,
did not interfere with the quality of care for patients, they were

Companies that manufacture safety needles.
 Abbott Laboratories 
Alaris Medical Systems 
Bayer Corporation 
Becton Dickinson 
Equidyne Systems 
Gettig Technologies 
Greiner Vacuette North America 
ICU Medical 
Johnson & Johnson 
Lukens Medical R Medical Safety Products
Medisys Technologies 
Molded Products 
New Medical Technology 
North American Medical 
Owen Mumford 
Retractable Technologies 
Roche Diagnostics 
Safety 1st Medical 
Safety Medical Supply 
SIMS Portex 
Tri-Ject International 
Tri-State Hospital Supply 
Tyco Healthcare Kendall
U.S. Medical Instruments 
Venetec International

Retraction Needles

This page has some artsy photos of how its retractable syringes work.
?The Safety Syringe is a 1cc fixed needle hypodermic, which has an
automatically retracting needle activated at the end of the injection
stroke. The device eliminates needle stick injuries and is used in the
medical industry, in immunisation programs, by insulin dependents and
in the various needle exchange programs throughout the world.
2.3. Principal function(s)
The Safety Syringe can be manufactured in sizes from 0.3ml to 10 ml,
with minimal additional production costs to that of a standard
syringe. As the plunger is depressed to the point where all the fluid
has been expelled, the sacrificial needle housing pierces through the
diaphragm, allowing the spring to fire the needle into the plunger,
where it is permanently trapped.
The primary purpose of the Safety Syringe is to reduce or eliminate
workplace and general use needle-stick injuries, which can expose the
population to a number of blood-borne pathogens that can cause serious
or fatal infections.?

?Without question, retractable needles are the safest injection
devices. The Analytica Retractable Syringe looks, feels and performs
like a standard syringe. The Retractable Syringe is an integrated
safety design system that aims to eliminate needle-stick injuries at
the source by retracting the needle. On complete depression of the
plunger, the patented Analytica technology automatically retracts the
needle, locking the plunger and disabling the syringe from reuse. The
Retractable Syringe uses interchangable needles for greatest

?A retractable syringe looks like, and feels like a standard syringe,
is operated in the same way as a standard syringe, and is permanently
disabled after use because the plunger locks down inside the body of
the syringe, locating the retracted needle safely within the plunger.?

This page shows how several types of retractable syringes work:

BD Retractable syringe needles

Sliding Covers

??  In the activated position the needle guards against accidental
needlestick during normal handling and disposal of the used
needle/syringe combination
?  The cover mechanism reaches the needle point, slides over it and
provides a secure encapsulation
?  This can help prevent needlestick by allowing easy and secure
shielding of the needle tip immediately after injection!22

?The Perifix Safety Epidural Needle uses B. Braun's safety clip
technology to reduce the needlestick risk for the epidural needle with
virtually no change in your technique. The safety clip is positioned
within the yellow plastic housing near the hub of the needle. When it
is convenient for you to activate the safety clip, you advance the
plastic housing to the tip of the needle until the safety clip


Blood Collection Needles

You didn?t ask about blood collection needles used with vacuum tubes,
but since these are used more than syringes, I thought I?d include
them too.

?Eclipse Safety Needle offers a single-handed, needle-based safety
injection device. The BD PrecisionGlide? Needle is bevel oriented to
the safety cover to facilitate low-angle injections.?

The cover illustration on the following document shows a safety cap on
a blood collection needle:
1. The safety feature can be activated using
a one-handed technique.
2. The safety feature does not interfere with
normal use of this product.
3. Use of this product requires you to use the
safety feature.
4. This device does not require more time to
use than a non-safety device.
5. The safety feature works well with a wide
variety of hand sizes.
6. The device allows for rapid visualization of
flashback in the catheter or chamber.
7. Use of this product does not increase the
number of sticks to the patient.
8. The product stops the flow of blood
after the needle is removed from the
catheter (or after the butterfly is inserted)
and just prior to line connections or
hep-lock capping.
9. A clear and unmistakable change (either
audible or visible) occurs when the safety
feature is activated.
10. The safety feature operates reliably.
11. The exposed sharp is blunted or covered
after use and prior to disposal.
12. The product does not need extensive
training to be operated correctly.

Vacutainer safety devices

Needle-less injection syringes

Then of course, there is THIS retractable syringe (joke):

    Of course, no safety device will work if not utilized properly. I
still see recapping of needles, or safety caps not being used, with
the whole, uncapped syringe placed in the sharps box! I even found a
picture (below). I contracted hepatitis when a co-worker gestured with
a needle, just withdrawn from a hepatitis patient, and stuck it into
me!  As previously mentioned, butterfly needles are notorious for
causing needle stick injuries.

I hope this has answered your questions. If anything is missing or
unclear, please request an Answer Clarification, and allow me to
respond, before you rate. I?ll be happy to assist you further on this
question, before you rate.

Sincerely, Crabcakes

Search Terms
Retractable + syringe + needles
Safety needles + syringe
Vacuum tube + safety collection needles
Safety syringe + needle + failure
Retractable syringe needles
jess05-ga rated this answer:5 out of 5 stars
Thank you for the great information!

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