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Team Breath Alert | 1
Design Context Review: Apnea Monitors in the Developing World Rachel Alexander, Rachel Gilbert, Jordan Schermerhorn, Bridget Ugoh and Andrea Ulrich
Physiology and Prevalence
Apnea, a cessation of breathing usually occurring when a patient is asleep, is a
common affliction that can have detrimental health effects.1 An apneic event is defined
as a period of 20 seconds or greater without a respiratory cycle, though when
accompanied by bradychardia (a heart rate under 80 beats per minute) or oxygen
desaturation (O2 < 80-85%) an episode may be classified as apneic in as short as 10
seconds.2 Apnea can be characterized as one of three types: obstructive, central, or
mixed. Central apnea involves both cessation of airflow and respiratory effort, resulting
from a weak or underdeveloped central nervous system. Obstructive apnea (Fig. 1) is
the cessation of breath despite respiratory effort, often due to muscle weakness in the
diaphragm in infants, the trachea in adults, or the way the trachea is positioned while
the patient is supine. Mixed apnea (also known as complex apnea) displays signs of both
central and obstructive apnea.3 Roughly 0.4% of all cases of apnea are central, 84% are
obstructive, and 15% are mixed.
Apnea is estimated to affect
nearly 40 million people in the
United States alone. Many of those
afflicted can cease breathing up to
100 times in a single hour.4
Physicians usually treat apnea by
supplying the patient with air with
greater-than-normal oxygen
content,5 assisting the patient using
physical or mechanical breathing
assist devices (such as a constant
positive airway pressure device), or
1 Stedman’s Medical Dictionary 28th edition. Lippincott Williams & Wilkins, 2006. http://dictionary.webmd.com/terms/apnea. Accessed 28 Sep 2011. 2 Nimavat, Dharmendra, Michael Sherman, Rene Stantin. “Apnea of Prematurity.” Medscape Reference. Ed: Ted Rosenkrantz. 6 Apr 2011. http://emedicine.medscape.com/article/974971-overview#aw2aab6b2b2 3 Morgenthaler TI, Kagramanov V, Hanak V, Decker PA (September 2006). "Complex sleep apnea syndrome: is it a unique clinical syndrome?". Sleep 29 (9): 1203–9. PMID 17040008. Lay summary – Science Daily (September 4, 2006). 4 Sleep Apnea.” Apneos. Apneos Corporation. 06 Sep 2003. http://www.apneos.com/sleepapnea.html. Accessed 28 Sep 2011 5 “Apnea of Prematurity.” A.D.A.M. Medical Encylopedia. Rev: 2 Nov 2009. Rev: Neil K Keneshiro, David Zieve. Accessed 28 Sep 2011. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004488/
Figure 1: Obstructive apnea may result from poor trachea positioning [1]
Team Breath Alert | 2
administrating caffeine citrate – a treatment method especially effective when used in
children.6
Risk Factors and Geographic Distribution
While sleep apnea in adults is generally a mild and non-life-threatening
condition, apnea in children can have much more severe consequences. It is estimated
that sleep apnea occurs in 2% of all children7, 7% of all infants (apnea of infancy, AOI)8,
and in 50% of all premature infants born prior to 36 weeks gestation (apnea of
prematurity, AOP).9 Children who are obese and those with enlarged tonsils are also at
higher risk for sleep apnea.10 Conditions such as anemia, malnutrition, heart or lung
problems, infection, low oxygen levels, overstimulation, and temperature problems can
all trigger or exacerbate apnea in children.11 If left untreated, apnea can lead to failure
to thrive, diminished growth, hypertension, cor pulmonale (failure of the right side of
the heart), developmental problems such as loss of IQ, mental retardation, hyperactive
behavior, acid reflux, development of a pectus excavatum deformation (sunken chest),
or, in severe cases, death.12,13,14
Among children, apnea is most prevalent in premature infants. Nearly half of all
premature babies suffer from AOP, while nearly 100% of premature babies born <28
weeks or at a birth weight <1000 g experience regular apneic episodes.15 Typically,
apnea in neonates results from their underdeveloped central nervous systems and weak
trachea muscles – both of which have not yet had the time to fully develop. At 45
weeks postconceptional age, symptoms tend to disappear as these organs mature.16
Some research indicates that AoP serves as a risk factor for sudden infant death
syndrome (SIDS); Moon et. al. found that infants with AoP were four times more likely
6 Finer, Neil N.,Rosemary Higgins, John Kattwinkel, Richard Martin. “Summary Proceedings from the Apnea-of-Prematurity Group. Pediatrics. Vol. 117 No. Supplement 1; 1 March 2006. pp. S47-S51. http://pediatrics.aappublications.org/content/117/Supplement_1/S47.long 7 “Sleep Apnea.” Apneos. 8 Rocker, Joshua, Jeffrey Israel. “Pediatric Apnea.” Medscape Reference. Ed: Richard G. Bachur. 25 Aug 2010. http://emedicine.medscape.com/article/800032-overview#a0199 9 Finer. 10 “Sleep Apnea.” Apneos. 11 “Apnea of Prematurity.” A.D.A.M. Medical Encylopedia. Rev: 2 Nov 2009. Rev: Neil K Keneshiro, David Zieve. Accessed 28 Sep 2011. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004488/ 12 “Sleep Apnea.” Apneos. 13 Joshua Rocker, et. al. 14 Cataletto, Mary E., Andrew J Lipton, Timothy D Murphy. “Childhood Sleep Apnea.” Medscape Reference. Ed: Michael R Bye. 29 Mar 2011. http://emedicine.medscape.com/article/1004104-overview#a0156 15 Finer. 16 Tauman, Riva, and Yakov Sivan, 2000. “Duration of Home Monitoring for Infants Discharged with Apnea of Prematurity.” Biology of the Neonate, Vol. 78, No. 3. pp 168-173. http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowAbstract&ProduktNr=224215&Ausgabe=225302&ArtikelNr=14266
Team Breath Alert | 3
to die of SIDS than those without.17 Therefore, it is vital that infants at risk for AoP or AoI
are carefully monitored to prevent death and other developmental complications.
A recent survey18 identified the global distribution of pre-term births. The
highest incidence occurred in Southern Africa, where 17.5% of all births are considered
pre-term. In fact, nearly 85% of all pre-term births in 2005 took place in Africa and Asia
(Fig. 2). In many of the world’s least developed areas – such as sub-Saharan Africa,
where premature birth rates are among the highest in the world – resources for
monitoring apnea in children are extremely limited, and often visual observation serves
as the only indication of
whether or not a child is
breathing19. Unmonitored
infants in these locations are
at higher risk of dying or
developing behavioral,
physical, and mental
disorders when compared to
their American and
European peers.
Measuring Breathing
Major methods of detecting apneic episodes in developed countries tend to rely
on both physical and chemical indicators; these include measurement of airflow,
motion, and blood oxygenation. Although none of these systems perfectly detect apneic
episodes, they each possess different advantages and unique design challenges. In
analyzing how these sensors could potentially be used in our device, we will examine
how sensors receive measurements as well as the advantages and disadvantages of the
systems, including sensor cost, complexity, and accuracy.
Airflow Sensors
Airflow sensors analyze patterns of breathing by measuring one or more of three
parameters: temperature, pressure, and acoustics. Although some of the systems are
relatively cheap, a facemask, mouth piece, or nosepiece is required to collect the
17 Cataletto, Mary E., Andrew J Lipton, Timothy D Murphy. “Childhood Sleep Apnea.” Medscape Reference. Ed: Michael R Bye. 29 Mar 2011. 18 Beck, Stacy, Daniel Wojdyla, Lale Say, Ana Pilar Betran, Maria Merialdi, Jennifer Harris Requejo, Craig Rubens, Ramkumar Menon, and Paul FA Van Look. 2009. “The worldwide incidence of preterm birth: a systematic review of maternal mortality and morbidity.” Bulletin of the World Health 19 Moons, Peter. “Re: Team Breath Alert Introduction.” E-mail to Team Breath Alert. 4 Oct. 2011
Figure 2: Distribution of preterm births around the world [2]
Team Breath Alert | 4
patient’s expired air for analysis, and are considered more invasive than sensors placed
elsewhere on the body22.
One type of airflow sensor uses a thermistor to measure the temperature
difference between ambient inspiratory air and lung-temperature expiratory air.
Respiratory rate is calculated by tracking changes in temperature over time: as the
temperature calculated approaches the ambient temperature, it is assumed that the
patient has gone an extended period of time without breathing. The thermistor is
shaped to form a bridge placed between the nostrils.20 This system, while low cost and
easy to use, must be calibrated for various lung sizes and may experience some delay
before detecting an apneic episode.20
Similar in principle to thermal sensors, pressure airflow sensors detect
fluctuations in airway pressure caused by respiration. Airflow pressure is measured
quantitatively with a pneumotachograph, a device that detects the pressure differential
between inspiration and expiration.21 Pressure airflow sensors can be used in the form
of a facemask or nasal cannula sensor. These are simple to use and require minimal
calibration, but may be prohibitively expensive for use in the developing world, starting
at $60 for the sensor alone. Existing pneumotachographs are also bulkier and perhaps
better suited for use in adults rather than infants.
Acoustic rhinometry measures air pressure as well as the airflow rate in the nasal
airway during respiration by measuring reflected sound waves directed towards the
patient’s pharynx.22 Many acoustic rhinometers require the user to hold the nosepiece
near the nostril while breathing into it.23 The accuracy of acoustic rhinometry can be
affected by sound interference from the patient’s heart beat. Furthermore, rhinometers
do not pick up accurate measurements from infants, largely because readings are only
accurate when patients breathe through their nose.24
Motion sensors
Another means of detecting apneic episodes relies on tracking chest motion.
Monitors relying on this technique tend to record motion artifacts – while premature
infants tend to be relatively still, older patients may move or roll in ways that expand
their chest cavities when not breathing – but the relatively sinusoidal nature of
20 Jovanov, Emil, and Dejan Raskovic. "Thermistor-based Breathing Sensor for Circadian Rhythm Evaluation." Web. <citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.127.5161>. 25 Sept. 2011. 21 Lee-Chiong, T. "Monitoring Respiration during Sleep." Clinics in Chest Medicine 24.2 (2003): 297-306. Print. 22 "Rhinometry and Rhinomanometry." Aetna - Health Insurance, Dental, Pharmacy, Group Life and Disability Insurance. Web. 07 Oct. 2011. <http://www.aetna.com/cpb/medical/data/700_799/0700.html>. 23 "Acoustic Rhinometer A1." GMI Home Page. Web. 07 Oct. 2011. <http://www.gm-instruments.com/A11.htm>. 24 Folke, M., L. Cernerud, M. Ekström, and B. Hök. "Critical Review of Non-invasive Respiratory Monitoring in Medical Care." Medical & Biological Engineering & Computing 41.4 (2003): 377-83. Print.
Team Breath Alert | 5
breathing makes it easy to filter out this noise. The three main methods of monitoring
apnea via chest motion include transthoracic impedance pneumography, stretch
sensors, and motion sensor pads.
Transthoracic impedance pneumography records inhalations and exhalations by
measuring the change in resistance to flow of electrical current across the patient’s
chest. Chest impedance changes as the pleural cavity expands and contracts with air
flow.25 This impedance shift alters current sent through electrodes placed on the chest
for straightforward measurements.26 Transthoracic impedance pneumography serves as
the gold standard for hospitals in the developed world because multiple physiological
monitors (including respiratory rate, heart rate and blood-oxygen level) can be obtained
using one data collection system. Impedance monitors are extraordinarily accurate, but
are also expensive and require a constant A/C power supply. Additional complications
disruption of accurate readings by aortic blood flow (relevant for infants, who often
have respiratory rates nearer in frequency to heart rates), and regular application of gel
to ensure low skin-electrode impedance is necessary throughout monitoring.27
The second technique uses stretch sensors that change resistance with
movement of the chest (Fig. 3).28 A wide variety of devices have been developed
utilizing changes in external sensor
resistance – for example, Guardian
Technologies has created a vest using
this technique.29 Although most of
these devices are inexpensive, there
are several clinical problems that are
present – for example, a vest structure
is not ideal if a nurse needs to examine
the child’s chest, and a vest could
serve as an obstacle slowing care in an
emergency. However, these sensors
could be incorporated in a variety of
designs, including less obstructive (if
25 Gupta, Amit K. "Respiration Rate Measurement Based on Impedance Pneumography." Texas Instruments, Feb. 2011. Web. <http://www.ti.com/lit/an/sbaa181/sbaa181.pdf>. 26 Sontheimer, D., C. B. Fischer, F. Scheffer, D. Kaempf, and O. Linderkamp. "Pitfalls in Respiratory Monitoring of Premature Infants during Kangaroo Care." Archives of Disease in Childhood - Fetal and Neonatal Edition 72.2 (1995): F115-117. Print. 27 Folke et al. 28 "Flexible Stretch Sensor." Images Scientific Instruments - Science Projects, Electronic Kits, Robotic Kits and Accessories, Microcontroller Compilers and Programmers, Parts. Web. 07 Oct. 2011. <http://www.imagesco.com/sensors/stretch-sensor.html>. 29 Guardian Technologies, 2009. Web. <http://biibs.sdsu.edu/vest.html>.
Figure 3: Apnea Belt Monitor [3]
Team Breath Alert | 6
less physically stable) belts.
Lastly, pressure sensors may be placed in the child’s mattress to monitor chest
movement. These mattress sensors are common for at-home apnea monitoring in
developed countries. These mats can be difficult to position to achieve accurate
measurements,30 and they are easily dislodged by infant motion, and are plagued by the
highest rates of false alarms.31 On the other hand, these sensors are extremely non-
invasive and simple to implement.32
Blood Gas Measurement
Blood gas monitors measure respiration indirectly by examining blood
oxygenation levels. Two types of blood oxygenation measurement techniques are pulse
oximetry and O2/CO2 level sensing.
The pulse oximeter monitors blood oxygen levels by utilizing infrared light
generated by the device that passes through a finger, toe, wrist, or earlobe of the user.33
During an apneic episode, the pulse oximeter detects a drop in blood-oxygen saturation
levels due to a lack of oxygen entering the blood stream via the lungs. Normal levels of
arterial oxygen saturation range from 95% to 100% for infants and for adults; 34 for
preterm babies, the arterial oxygen saturation levels range from 84% to 90%.35
Saturation levels below these ranges may indicate that the patient has entered an
apneic state and requires oxygen. Pulse oximeters are easy to use but are unstable and
difficult to position correctly.36
An O2/CO2 sensor uses airflow to measure the blood gas concentration of
expelled air from the patient and correlates it to arterial blood concentration.37 An
increase in CO2 or a decrease in O2 may indicate that the patient has entered an apneic
state. One problem with this type of measurement lies in the fact that the concentration
of CO2 and O2 do not correlate exactly to the arterial blood concentration. The monitor
30 Angelcare Baby Monitor | Babyphone and Baby Movement Sensor. Web. 07 Oct. 2011. <http://www.angelcare-monitor.com>. 31 Folke et al. 32 Folke et al. 33 "Pulse Oximetry and Sleep Apnea." Sleep Apnea Life - Living with Sleep Apnea. Web. 07 Oct. 2011. <http://sleepapnealife.com/pulse-oximetry-and-sleep-apnea-311.html>. 34 "Normal Oxygen Saturation For Infants | LIVESTRONG.COM." LIVESTRONG.COM - Lose Weight & Get Fit with Diet, Nutrition & Fitness Tools | LIVESTRONG.COM. Web. <http://www.livestrong.com/article/139666-normal-oxygen-saturation-infants/>. 27 Sept. 2011. 35 "Normal Hemodynamic Parameters and Laboratory Values." Edwards LifeSciences LLC, 2011. Web.<http://ht.edwards.com/sci/edwards/sitecollectionimages/edwards/products/presep/ar04313hemodynpocketcard.pdf>. 25 Sept. 2011. 36 Folke et al. 37 Folke et al.
Team Breath Alert | 7
assumes an ideal correlation and thus measuring CO2 and O2 changes can be
inaccurate.38
Table 1: Summary of the advantages and disadvantages of methods of detecting respiratory rate
Method Advantages Disadvantages
Airflow Sensors
Temperature Low cost, easy to use Intrusive
Pressure Easy to use Expensive
Acoustics Low cost Potential noise
interference, limited
monitoring capabilities
Motion Sensors
Transthoracic Impedance
Pneumography
Widely used in developed
world, accurate
Expensive, high power
requirement
Stretch Sensors Low cost, easy to use Noise interference, may
require significant chest
movement
Pressure sensor mats Noninvasive Expensive, motion artifacts,
positioning, high power
requirement
Blood Gas Measurement
Pulse oximeter Low cost, easy to use Signal delay, may fall off,
positioning
CO2/O2 Sensor Low cost Ease of use, inaccurate,
intrusive
With a wide variety of airflow, motion and blood oxygenation monitoring
techniques, no clear winner emerges as the best all-around technology – the manner in
which each technology is implement seems the key to success. Several technical
problems, from motion artifacts to cost, may prove challenging to solve and might
require intense processing. In order to narrow our options, we will now consider
additional barriers imposed when using these devices in countries with the highest rates
of premature infants.
38 Folke et al.
Team Breath Alert | 8
Low-resource Settings
To best assist patients in low-resource settings, it is important to understand
additional problems that may be faced exclusively by those health care professionals.
There are two primary economic categories used to describe lower-income countries:
“developing” nations, as well as “least-developed countries.” A “developing” nation
encompasses a wide range of countries – including a per capita income range from $80
to $8,380 (Mozambique and Argentina, respectively).39 Least-developed countries
(LDCs) refer to the most economically weak members of the developing countries, and
include 45 countries such as Malawi, Bhutan, and Angola.40 The United Nations selects
the LDCs by certain criteria, including a gross national income (GNI) per capita of less
than $900, as well as meeting a certain threshold on human and economic
vulnerability.41
Manufacturing Capabilities
Lack of infrastructure and shortages of technical personnel often leave LDCs
unable to manufacture and transport complex goods, including medical devices such as
the apnea monitoring systems previously mentioned. When importing these goods from
other nations, trade regulations may require price controls and tax regulations, both of
which are frequently compromised due to political instability. Furthermore, the ability
to adopt and operate high-end technologies is compromised by the lack of technical
expertise in developing countries. In LDCs especially, consistently low rates of secondary
education impede rapid technology adoption.42
Technology Awareness
There are several technology gaps impeding the implementation of health
devices in the developing world. Power is unreliable at best, and often no stable source
of power can be found.43 In Malawi, for example – frequently cited as one of the worst
case scenarios for healthcare access, and largely representative of the areas in which we
hope to implement our device – it is not uncommon for hospitals to face power
blackouts every day, and hospitals with better infrastructure may still experience
39 Trybout, James. Manufacturing firms in developing countries: how well do they do, and why? Journal of Economic Literature. 38 (1): 11-44, 2000. 40 Department of Economic and Social Affairs Statistics Division Office of the High Representative for Least Developed Countries, Landlocked Developing Countries and Small Island Developing States. World statistics pocketbook 2010: least developed countries. LDC. 35: 1-75, 2011. 41 “The Criteria for the Identification of LDCs.” United Nations. 2005. Accessed 6 Oct. 2011. <http://www.un.org/special-rep/ohrlls/ldc/ldc%20criteria.htm>. 42 Trybout. 43 Martínez, Andres, Valentín Villarroel, Joaquín Seoane, and Francisco del Pozo. Rural telemedicine for primary healthcare in developing countries. IEEE Technology and Society Magazine. 13-24, 2004.
Team Breath Alert | 9
outages at least once a week.44 However, cell phone ownership and coverage are
increasing rapidly in the developing world, with 85% 2G coverage reaching even the
most desolate areas.45 The market for health-related mobile apps is predicted to expand
with a compound annual growth rate of 24% between 2010 and 2014.45
Environment
Technologically complex apnea monitors may not operate accurately in the
extreme heat and humidity commonly present in open-air hospitals in LDCs. High
humidity may cause devices to rust and affect sensor readings. In Malawi, again
representing an extreme scenario in which our device might be implemented, humidity
can reach 80% in the rainy season from October to May.46 Changes in temperature
affect the operation of electrical components such as thermistors and resistors and may
make the medical device less accurate. Temperatures in Malawi swing between
extremes: temperatures can drop to just above freezing on winter evenings and rise to
as high as 42 C̊ during the summer.46
Health Care in Low-resource Settings
Health systems in developing countries are struggling to meet the needs of their
sick. Worker shortages and budget deficits negatively impact essential measures of
population health such as infant mortality
rate. A meta-analysis of how various risk
factors affect global disease burden and
Disability-Adjusted-Life-Years (DALYs)
showed that the poorest nations suffer more
loss of life than any other region of the
world. It becomes fairly clear that the areas
of the world struggling with the most
sickness are also the poorest regions of the
world (Fig. 4).47 With child mortality
specifically, neonatal deaths serves as a key
indicator: neonatal deaths account for about
one third of the global child mortality rate.
For every 1000 births, 40-50 babies born in
44 Sandy Chiume. Personal interview. 6 Oct. 2011. 45 "Mobile Enterprise Applications Market 2010-2014." Technavio (2011). 46 “Human Resources for Health Country Profile - Malawi.” Africa Health Workforce Observatory. Oct. 2009.) 47 Ezzati, Majid, Alan Lopez, Anthony Rogers, et al. Selected major risk factors and global and regional burden of disease. The Lancet. 360 (9343): 1347 – 1360, 2002.
Figure 4. A measure of Disability-Adjusted Life Years compared to diseases burdens worldwide
Team Breath Alert | 10
all LDCs combined die in the first 28 days of life.48
Governments in these countries are ill-equipped to address these health issues,
often facing issues with political instability capable of crippling healthcare systems.49
Worker shortages also pose serious challenge (Table 2). This pattern is notably worse in
sub-Saharan Africa, where 3% of the planet’s healthcare workers treat 25% of global
disease burden.50
Table 2: Medical Staff per 100,000 People in Six Sub-Saharan Countries, 200451
Nurses are the primary party responsible for monitoring patients’ health. A study
in the U.S. indicated that lower nurse-to-patient ratio led to worse patient outcome.52
Furthermore, patient crowding leads to significant restraints on hospitals. Struggling
with minimal equipment, nurses often assign multiple patients to a bed, and it is not
uncommon for multiple babies to share one ventilator.53
Conditions Faced by Nurses and Doctors
In hospitals in the developing world, nurses face extreme stresses due to
crowding, poor communication, hostile work environments, and lack of training (Fig. 5).
Communication between doctors and nurses is often strained, as determined by an
American study examining nurses and doctors in 36 emergency rooms. When
questioned on the effectiveness of doctor-nurse communication, both doctors and
nurses stated that tasks were often done by both parties because of lack of
communication. It was found that doctors blame nurses for mistakes more than they
blame other doctors.54 Breakdowns in communication serve as major sources of stress
in the healthcare system.
48 Zaidi, Anita, W. Huskins, D. Thaver, et al. Hospital-acquired neonatal infections in developing countries. The Lancet. 365 (9465): 1175 – 1188, 2005. 49 “Human Resources for Health Country Profile - Malawi.” Africa Health Workforce Observatory. Oct. 2009. 50 Do most countries have enough health workers? World Health Organization, 26 Feb. 2008. Web. 25 Sept. 2011. <http://www.who.int/features/qa/37/en/index.html>. 51 Palmer. 52 Carayon, Pascale and Ayse Gurses. “Nursing Workload and Patient Safety – A Human Factors Engineering Perspective.” Patient Safety and Quality: An Evidence-Based Handbook for Nurses, edited by R.G. Hughes. Rockville: Agency for Healthcare Research and Quality, 2008, pp. 2-203 – 2-216. 53 Bateman, Chris. “Crowded wards, lousy admin contribute to death and suffering.” SAMJ 100(7) (2010): 414-418. Web. 25 Sept. 2011 54 Greenfield, Lazar J. “Doctors and Nurses: A Troubled Partnership.” Annals of Surgery 230(3): 279. 1999. Web. 25 Sept. 2011.
Team Breath Alert | 11
When a general
health questionnaire was
administered, 40% of
general ward nurses and
32% of neonatal nurses in
Sydney had scores
indicating possible
psychological impairment,
indicating conditions such
as depression, anxiety,
and fatigue derived from
work-related stress.55
During high levels of stress, health officials often experience memory impairment,
decreasing the ability of nurses to attend to their patients.56 One study examining the
relationship between ward noise and heart rate found that any noises above the
average daytime noise level of 61 dB resulted in significant increases, indicating higher
stress.57 We anticipate that all of these stresses would be exacerbated in the developing
world.
The lack of training and support nurses receive in developing countries may also
serve as a stressor. Support resources are offered by the West and East African Health
Organizations, but access to these resources is limited.58 Many nurses receive minimal
training, often on the job, and afterwards suffer from a lack of supervision and support
from the hospital itself.59
Design Constraints for Apnea Monitors in LDCs
Frequently dire conditions in LDCs present us with several key constraints that
define how we as a team opt to address the problem of apnea detection:
We cannot assume that hospitals in the developing world will be able to
utilize the constant source of A/C power, frequent automated calibration,
or a significant amount of monitoring available in the US.
55 Oates, P.R., Oates, R.K. “Stress and work relationships in the neonatal intensive care unit: are they worse than in the wards?” Journal of Paediatrics and Child Health Vol 32 Issue 1 (1996): 57-59. Web. 20 Sept. 2011. 56 Newell, Robert. “Anxiety, accuracy and reflection: the limits of professional development” Journal of Advanced Nursing 17 (1992): 1326-1333. Web. 25 Sept. 2011 57 Morrison, W.E., Haas, E.C., Shaffner, D.H. et al. “Noise, Stress and Annoyance in a Pediatric Intensive Care Unit.” Critical Care Medicine 31(1) (2003): 113-119. Web. 25 Sept. 2011. 58 Koop, C. Everett, Pearson, Clarence E., Schwarz, M. Roy. Critical Issues in Global Health. San Francisco: Jossey-Bass, 2001. Print. 59 Palmer.
Figure 5: Kamuzu Central Hospital Children Ward’s A (Malawi) [5]
Team Breath Alert | 12
Worker shortages create chaotic, hectic pediatric wards with low nurse-
to-patient ratios; a monitor that does not require constant human
monitoring is ideal.
Given noise and stress issues in neonatal wards, an ideal monitor would
be extremely easy to use and would require minimal training. Automatic
logging of episodes and construction of patient medical records would
further alleviate stressors.
Our monitor will need to be self-contained and resistant to
environmental extremes.
Due to the lack of manufacturing capabilities, the device should be
constructed in the United States and then shipped to the LDC of interest,
complete with replacement parts.
Lack of technical expertise means the device should be as rugged and
self-sufficient as possible.
Given the widespread availability of cellular networks, a monitor that can
interface with wireless networks may significantly aid the health workers.
High sensitivity and specificity remain our most important objectives, and
should not be sacrificed as a function of environmental limitations.
Most importantly, that the device accurately identifies when the infant is not
breathing for a designated period of time. Sensitivity and specificity must be seriously
considered in designing an appropriate apnea monitor, and remain our most important
objectives.
Problem Statement
In developing nations, 10.9 million premature babies are born each year.
Roughly half of them suffer from apnea of prematurity (AOP), which could lead to
serious complications and even death if left untreated. Current apnea monitors that are
widely used in the developed world are not suitable for application in low-resource
settings. Many of these monitors are not very sensitive and require an external power
source or frequent calibration. Furthermore, current devices are designed with the
assumption that only one baby is being monitored, while crowded neonatal wards often
have low nurse-to-patient ratio. Properly monitoring apnea of prematurity requires a
robust, inexpensive, user-friendly device that can be integrated into crowded neonatal
wards in developing countries.
Team Breath Alert | 13
Work Cited for Figures and Tables
[1] http://www.91outcomes.com/2010/09/blogging-about-gulf-war-illnesses-sleep.html
[2] http://www.physorg.com/news173880803.html
[3] http://www.nationwidechildrens.org/apnea-prematurity
[4] Figure 1b. Ezzati, Majid, Alan Lopez, Anthony Rogers, et al. Selected major risk factors and global and
regional burden of disease. The Lancet. 360 (9343): 1347 – 1360, 2002.
[5] http://webscript.princeton.edu/~sgac/malawi/stories.php