JOHNS HOPKINS UNIVERSITY
An Alternative Infant
Incubator
Incubators for Third World Countries
Qingwen Kawaji
An infant incubator designed for third world countries in Eco Health Engineering led by Dr.
Thakor.
Medical Need and Background Information:
Incubator is the most common device that can provide an environment where newborn
babies can healthily grow in. Although incubators are used for all infants, they are especially
important in the case of preterm babies. There are a few reasons that contribute this need.
Firstly, infants’ large surface area, poor thermal insulation and a small mass (especially for those
with a low birth weight) all contribute to infants’ bodies behaving as a heat sink, which is why
infants have poor temperature regulation.i Secondly, infants aren’t like adults; when they are
cold, they cannot help themselves with a blanket. Babies exchange heat with their environment
by conduction, radiation, convection, and evaporation. Preterm babies are at especially high risk
of heat loss due to “a high surface area to volume ratio and increased transepidermal water
loss.”iiFurthermore, the normal surge in metabolic rate that occurs after birth is much reduced,
which results in limited heat production. Finally, “development in the control of skin blood flow
is also delayed in the immature baby, reducing the ability to maintain heat by peripheral
vasoconstriction.”iii With heat loss through four different methods and an inability to produce and
maintain heat, preterm infants are at high risk for medical complications and death.
To make matters worse, preterm infant birth rates are especially high in developing
countries, where the facilities and the after-birth care are the worst. The combination of poor
facilities, poor after-birth care, and a lack of knowledge propelled preterm birth to be one of the
leading causes of infant mortality in developing countries. According to World Health
Organization, it is estimated that in 2005, “12.9 million births, or 9.6% of all births worldwide,
were preterm.”iv About 85%, or 11 million of all preterm births took place in Africa and Asia,
deeming preterm birth is a leading cause for neonatal mortality and morbidity.v
Several studies have shown that infant survival rates significantly increase when their
surrounding environment is ideal. vi Infants thrive at a specific temperature range, the
temperature that’s very similar to body temperature. Preterm infants lose heat quickly and
cannot regulate their own body temperature. Being able to provide such warmth is a great value
to a baby’s health, this is especially true for preterm infants. Hospitals all over the United States
use incubators to provide a steady and ideal environment for preterm babies. However, this
luxury does not exist in developing countries.
Two major obstacles that are keeping the developing countries from having these
helpful devices are accessibility and price. An example of the state of the art incubator, used
often in high ranking hospitals in the US, is the Giraffe Incubator produced by GE health care.
These incubators not only have extremely precise
and accurate temperature control, they also have
countless other functions such as controlled
humidifier, built in scale, oxygen intake measure,
and etc. These incubators are also “smart,” in a
way that they can record data and be connected to
Figure 1 Giraffe Incubator From GE
the main computers at the hospital to be controlled
virtually. Incubators with such complicated process
programs cannot be used anyone. One must receive proper training provided by GE
Health Care in order to be qualified to operate. These trainings alone cost up to $4000
dollars. One can only imagine the actual cost of the machine. Of course, this is an
incubator that’s on the top of the shelf. However, the average cost of incubators in most
hospitals is still more than just a few thousands. This price, may be reasonable to
hospitals in the developed countries, is impossible for third world countries. Before price,
there is also the question of accessibility. Even if developing countries were to obtain
incubators as a donation from developed countries, it would be hard for them to learn an
entire system of operations of these new machines. Also, because these machines are
built elsewhere, it is virtually impossible to find the same parts for replacement or fix-ups
in these developing countries if anything were to go wrong with these incubators.
The purpose of this project is to strike a balance between price and functionality,
to invent an incubator that’s good at what it must do -- to keep baby warm and healthy,
but does not cost a whole village’s fortune. Also, the incubator must be built with
materials that are readily accessible in the home country so that trained staff can easily
replace and rebuild.
Analysis of Current Devices:
The problem of incubators has been tackled by a variety of organizations. Currently,
there are a few incubators available to third world countries. Although each one has its
merits in one way or another, they all have areas that need improvements. Before diving
into our design, we must assess each of the already existed projects to gain insights as to
how ours can be more useful.
The Embrace is one of the current devices in providing infant care. The
design costs $25. However, although the device is very cheap, it has many
downfalls. The mechanics of this device involves heating the phasechange material in the device using hot water or an electric heating pad.
The pouch will heat up to 37 degrees (the ideal incubator temperature)
Figure 2 The Embrance
and placed into the sleeping bag.vii The sleeping bag then wraps the baby
inside to keep them warm. The phase change material will stay around the
same temperature for about four hours. Then it would need to be heated up again.
Although innovative, this incubator does not have any temperature control within, which
is crucial to any device. Without an temperature control, no one would notice if anything
were wrong with the device, if it would to be defective. Furthermore, wrapping the baby
in a sleeping bag forbids caregiver to observe the baby openly, which is important in
many cases to determine a baby’s reaction to the environment or whether or not they are
sick.
The Car Part Incubator is another interesting innovation. The idea of
this incubator is to provide an device that can reuse old car parts. This
solution, while mildly low cost ($1000), need vehicle parts, which can
be expensive and unattainable.viii In third world countries, working car
Figure 3 Car Part
Incubator
parts cannot be cheap. Most of these parts are used to build “new” cars
or to fix cars rather than to be sold for incubators. Another problem
with this design is that there is no access to the infant through “sleeves.” It has not been
tested for its ability to prevent infections and bacteria
growth. It is also fairly complicated to build.
The HEBI (Hemel Baby Incubator) is an incubator project
launched by Dr. Hemel and first used in Uganda in 1968.ix
Figure 4 HEBI Incubator
This incubator cost about $500, not including the light bulbs. It also has to be shipped
from Amsterdam airport to any developing countries in need. This incubator uses
incandescent light bulbs are a source of heat. It has been tested to prevent infection and
bacteria growth. However, it does not have temperature control unit as it is heated solely
by turning on and off the lightbulbs. Another problem with this incubator is that it uses
the fact that incandescent light bulbs are inefficient and therefore emit heat. However,
because of this inefficiency, incandescent light bulbs have also been replaced by
fluorescent light bulbs and to make the world a “greener” place, most companies have
stopped producing them.
Solution and Design
Through studies and analysis of the current designs, we have gathered their pros and cons
and created our very own incubator.
Incubator Material
Wood
Incubator heat source
Car Heater
Incubator ventilation
Used PC Fans
Incubator Humidifier
Aluminum foil cooking pan
Incubator window
Polyethylene sheets and Window film
Incubator Temperature Control
Digital Temperature Control with Sensor
LM 335
The incubator will be built from wood due to its accessibility and price. Also, we have
contacted the HEBI organization and through them we learned several reasons why they
used wood as the construction material for incubators: 1) wood gives a strong
construction; 2) wood has good insulation; 3) it’s easy to regulate relative humidity; 4)
it’s easy to obtain especially in third world countries. The material of the observation
window in most incubators is acrylic glass. This material is expensive and hard to get in
third world countries. In order to replace acrylic glass with another material that’s safe to
use and also provide insulation and clear observation, we contacted 3m company and
decided to use polyethylene sheets. Firstly, when polyethylene sheets breaks, it will not
harm the baby in anyway. Secondly, polyethylene sheets are cheap and easily available.
In order to improve the UV
reflection ability of these
polyethylene sheets, window
films are used to adhere to the
polyethylene sheets.
As for heat source, car heaters
are used due to their availability,
price, and efficiency. This heater
is also part of the humidifier
system embedded under the
main incubator. The humidifier
system involves a cooking pan
filled with water, heater, and PC fans. Used PC fans are used for ventilation of the
incubator to allow exchange of air. Finally, the thermo-regulator unit is used to adjust and
relay the system. When the temperature rises above 38 degrees, the regulator turns off the
heater until the temperature inside the incubator has fallen down to a specified 36 degrees.
The fans will be turned on when the unit is above 38 degrees and off when it’s below 36
degrees. This relay system is important in the regulation of the temperature inside the
incubator. Below is a diagram of the thermo-regulation unit and of its inside circuitry.
Furthermore, in order to protect the
circuitry of the thermo-regulator unit,
a special case was specifically
designed using pro-engineering and
U-print 3D prototype printer. This
case perfectly encloses the thermoregulator unit while offering an LCD
screen view and exposing the
switches for temperature displays.
Cost analysis
Overall Design Analysis
i
Lyon, Andrew. (2006) "Applied physiology: Temperature control in the newborn infant." Current
Pediatrics 16, 386-392
ii
Lyon, Andrew. (2006) "Applied physiology: Temperature control in the newborn infant." Current
Pediatrics 16, 386-392
iii
Lyon, Andrew. (2006) "Applied physiology: Temperature control in the newborn infant." Current
Pediatrics 16, 386-392
iv
Beck, Stacy, et al. “The Worldwide Incidence of Preterm Birth: A WHO Systematic Review of Maternal
Mortality and Morbidity.” Bulletin of the World Health Organization (2009): 10.2471.
v
Beck, Stacy, et al. “The Worldwide Incidence of Preterm Birth: A WHO Systematic Review of Maternal
Mortality and Morbidity.” Bulletin of the World Health Organization (2009): 10.2471.
vi
Day, Richard L., et al. "BODY TEMPERATURE AND SURVIVAL OF PREMATURE INFANTS."
Pediatrics 34.2 (1964): 171-81.
vii
The Embrance. Web. <http://embraceglobal.org/>
viii
Design That Matters. Web. <http://www.designthatmatters.org/news/dtm-blog/project/incubator/>
ix
HEBI Hemel Baby Incubator. Web.
<http://www.hebiincubator.org/templates/heb/global/index.php?lngid=2&sqlmode=1&fid=144>