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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]

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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

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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]

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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]

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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.

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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.

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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.

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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.

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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