Replacement Solutions for Cracked Infant Warmer Plastic Walls
1. Introduction
At Jose Nieborowski Hospital, we interviewed Nurse Daris Henriquez in the delivery
room about certain problems she encountered in her line of work. She was very
concerned about the cracking in the plastic walls of the neonatal infant warmers
(NIW-3500 Infant Care Centers). Her hypothesis was that due to the prolonged
usage of the overhead lamps, the plastic underwent thermal degradation. Cracks
along the side of the plastic wall were repaired using stitches (see Figure 1). With
the already limited number of infant warmers in the hospital, this prompted us to
perform further investigation of how to solve this problem.
Before we began our research, we came up with a list of questions to better
understand the situation. Below is a the interview with Nurse Daris Henriquez
1. Does the plastic have to be translucent?
Yes, the barriers must be translucent such that we can easily see the infant from
all angles.
2. What type of protection can we add? (e.g. additional plastic, cloth, paint,
liquid spray-on coating, tape)
Cloth and metal can’t work because they aren’t transparent; and paint cannot
work because of compatibility with the infant. A plastic covering is a possibility,
in the form of a tape or sheet. Also, my dad works with vehicles and we think
replacement plastic, like fiberglass, can work. But we don’t know if fiberglass is
compatible with babies.
3. How long does the plastic generally last for?
The plastic cracks after 5-7 years of use.
4. What is the life expectancy of an infant warmer?
We have used different infant warmers for over 7 years. We have never
replaced them.
5. What is the difference between the plastics used in for infant incubators
versus infant warmers?
I am not sure. But the phototherapy units that are placed above the incubators
do not have the same magnitude of heat that infant warmers do. (also, in our
research, incubators work more like green houses and as such the plastic isn’t
under as much thermal stress as infant incubators). So the plastic in the
incubators has not become cracked.
6. What are the barriers to getting replacement walls?
The plastic is expensive because we can only find exact replacements in Japan
and it is very expensive to have them shipped.
Objective
2. The objective of this report is to find a solution to impede the thermal degradation
process of the plastic walls found in infant warmers, which results in cracking of the
plastic, and to present alternative plastics for replacement of the cracked plastic
walls.
Replacement Solution
The easiest solution for hospitals in Nicaragua is replacement of the plastic. In order
to work effectively and properly, the replacement plastic must both be compatible
with infants’ skin and thermally resistant. The currently used plastic on these infant
warmers is a type of acrylic plastic. This plastic lasts about five to seven years before
cracking and is compatible with babies. Two good alternative plastics to the acrylic
are polycarbonate and fiberglass. Polycarbonate has been used for many years in
medical applications ranging from endoscopic devices to plastics that carry food.
Polycarbonate is also thermally resistant and is more durable than acrylic.
Fiberglass is used in different medical devices’ apparatuses that come in contact
with the human body and has good thermal resistance as well as a resistance to
thermal expansion. Therefore, both polycarbonate and fiberglass are suitable
replacement plastics for the original acrylic plastic on the infant warmers.
We traveled to Managua and found a store called Display de Nicaragua that can
work with making a replacement plastic. At Display de Nicaragua, which is located
near Rotonda Bello Horizonte, we talked with Cristhian Miranda (email:
ventas10@displaynicaragua.com phone: +505-2251-5149) about a quote for our
problem. He told us that he has two different plastics available that could fix our
problem: 3mm thick polycarbonate and 9 mm thick acrylic. We showed him pictures
and described the problem and he believes that they can easily make a replacement
plastic with both the correct size and hinges for accessibility. He just needs one set
of the plastic walls so that he can cut the correct shape. He also gave us a rough
estimate of a quote, without the 15% tax for the pieces in acrylic and polycarbonate..
Acrylic Polycarbonate
Two side walls C$ 2,600.00 C$ 1,000.00
Front wall C$ 1,000.00 C$ 400.00
Because the polycarbonate is 1/3 the thickness of the acrylic, it is cheaper. But it is
also more flexible. Further discussion with Cristhian is needed to determine which
plastic is better for use as a replacement. Display de Nicaragua did not have
fiberglass available in their store, but if another avenue is available to construct
replacement walls out of fiberglass, it is a suitable option.
We suggest that Jose Nieborowski Hospital communicate further with Display de
Nicaragua or another avenue for fiberglass to determine exactly what procedures
and costs are needed in this project to replace the plastic.
Cleaning Methods
3. Another vital key to prolonging the life of the plastic is to use the correct cleaning
method. Using the wrong cleaning method can result in weakening and cracking of
the plastic; therefore, incorrect cleaning technique combined with the exposed heat
quickens the cracking process.
The best way to clean acrylic or polycarbonate plastics is with a mild solution of
soap and water. Only using water to clean the acrylic plastic is also suitable. Apply
the solution using a soft cloth or a microfiber cloth (e.g. Windall).
DO NOT USE window-cleaning fluids when cleaning acrylic plastics (e.g. ammonia,
gasoline, alcohol, or acetone) as they can cause cracking over time. For
polycarbonate and fiberglass products, a solution of mild detergent and water can
be used for more difficult stains.
For general purpose cleaning, use the following steps:
1. Use generous amounts of lukewarm water to rinse plastic and soften dried
dirt.
2. Make up a solution of lukewarm water & mild soap; a sponge or soft cloth
should be used to gently remove dirt and grime.
3. Rinse with clean lukewarm water and repeat washing if necessary.
4. After final rinse dry off with a soft cloth.
Protective Shielding
Another solution to increase the thermal resistance of the walls is to use a type of
protective shielding. After talking with an R&D Senior Engineer at BD, we came
upon a few different types of plastic protective shielding: polytetrafluoroethylene
(PTFE), ultra high molecular weight polyethylene (UHMW), polyetheretherketone
(PEEK), and fluorinated ethylene propylene (FEP). All of these are available in
sheets and possible in tapes as well. Furthermore, all of these have good thermal
resistance and have been used where contact with human skin is evident, such that
we believe they are compatible for use in this situation. PTFE is also chemically
resistant while UHMW and FEP are impact resistant, and PEEK is wear resistant.
Our travel to Managua detailed that this avenue of protection is unavailable here in
Nicaragua. However, if this option ever becomes available, we suggest using this on
top of the replacement plastic to increase the time the plastic lasts.
Conclusion
Replacing the cracked plastic walls of the infant warmers is a possible and cost
effective way to solve the problem. Display de Nicaragua is a great avenue for
completing this project. Furthermore, using the correct cleaning technique is of the
utmost importance to prolong the life of the plastic. Lastly, using a protective shield
is an extra method that can prolong the life of the plastic.
