Literature Survey Final Report

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LITERATURE REVIEW

DEVELOPMENT OF A CONTINUOUS POSITIVE

AIRWAY PRESSURE DEVICE

By

060558U H.G.D.B.S.Wimalarathna

Department of Mechanical Engineering

University of Moratuwa

Sri Lanka

09th November2009

Group No: 06


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---------------------------

Dr. Hans Gray

Project Advisor

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DECLARATION

I hereby state that this report contains no material which has been accepted for the award

of any other academic qualification in any University or equivalent institution in Sri Lanka

or abroad, and that to the best of my knowledge and belief, contains no material previously

published or written by any other person, except where due reference is made in the text of

this report.

----------------------------

H.G.D.B.S. Wimalarathna Date: 09.11.2009


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Abstract

Respiratory Distress Syndrome (RDS) is one of most common respiratory diseases that

caused to die many premature infants. The babies born prematurely have not yet started

making surfactant. Surfactant is a substance that helps keeps lungs open when breathing. As a

treatment for the RDS, the continuous positive airway pressure (CPAP) device is used.

However, the CPAP devices are also used for diseases called Obstructive Sleep Apnea

(OSA). Airway of some people becomes blocked or collapses, while they are sleeping. This

airway collapse causes a blockage, which can cause breathing to stop briefly. When breathing

stops for a short time, it is known as OSA.

The objective of this literature survey is to collect the information relating to the project,

which is about the background

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Abbreviations

CPAP - Continuous positive airway pressure

FIO2 - Inspired oxygen concentration

RDS - Respiratory distress syndrome

OSA - Obstructive Sleep Apnoea

IRV - Inspiratory Reserve Volume

PEEP - Positive End Expiratory Pressure

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Content

Abstract .................................................................................................................ii

Abbreviations ...................................................................................................... iii

Content .................................................................................................................iv

List of Figures ......................................................................................................vi

List of Tables ......................................................................................................vii

1.0INTRODUCTION ...........................................................................................1

1.1 BACKGROUND OF THE PROBLEM ........................................................................... 1

1.2 OBJECTIVES OF THE PROJECT ..................................................................................2

2.0 BASIC OF THE RESPIRATORY SYSTEM .................................................3

2.1 RESPIRATORY PROCESS ............................................................................................ 3

2.1.1 INSPIRATION ..........................................................................................................3

2.1.2 EXPIRATION ........................................................................................................... 4

2.2 BALANCE BETWEEN INSPIRATION AND EXPIRATION(Swan, 2006) .................4

2.2.1 FUNCTION OF THE ALVEOLI ............................................................................. 5

2.3 PRESSURE CHANGE DURING VENTILATION ........................................................ 5

3.0 INTRODUCTION TO CONTINUOUS POSITIVE AIRWAY PRESSURE

(CPAP) .................................................................................................................6

3.1 VENTILATION ............................................................................................................... 6

3.1.1 MECHANICAL VENTILATION ........................................................................... 7

3.1.2 NEGATIVE PRESSURE VENTILATION .............................................................. 8

3.1.3 POSITIVE PRESSURE VENTILATION ................................................................ 8

3.3 DESEASES THAT ARE USED CPAP TREATMENT ..................................................8

Respiratory distress syndrome (RDS) ................................................................................ 8

3.3.1 RESPIRATORY DISTRESS SYNDROM (RDS) ....................................................9

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3.3.1.1 ROLE OF SURFACTANT ................................................................................ 9

3.3.1.2 TREATMENT FOR RDS(Stevens, 2009) ......................................................10

3.3.1.3 CAUSES FOR THE PREMATURE BIRTH(Stevens, 2009) ..........................11

3.3.2 OBSTRUCTIVE SLEEP APNOEA .......................................................................12

4.0 WHAT IS CPAP WHY CPAP .....................................................................14

4.1 HOW DOES CPAP WORK ...........................................................................................15

4.2 THE CHALLENGE OF CPAP ......................................................................................15

4.3 IMPORTANT OF THE HUMIDIFICATION DURING CPAP ....................................16

4.4 HOW TO CHOOSE CPAP MASK ............................................................................... 16

4.5 BENIFIT OF THE CPAP(Canadian Lung Association, 2009) ......................................17

4.6 WHAT ARE THE RISK OF CPAP(AMERICAN THORACIC SOCIETY, 2005) ......18

5.0 CONCLUSION .............................................................................................18

Reference ............................................................................................................19

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List of Figures

Figure 1.1 : CPAP Treatment (Narendran et al., 2003)........................................1

Figure 2.2 : Inspiration (SWAN, J. 2006. Page 42)..............................................3

Figure 2.3 : Expiration (SWAN, J. 2006. page 43)..............................................4

Figure 2.4 : Alveoli (SWAN, J. 2006.page 30)....................................................5

Figure 2.5 : Pressure change during ventilation (Swan, 2006).............................5

Figure 3.6 : Mechanical Ventilation.....................................................................6

Figure 3.7 : CPAP Treatment for poor baby.........................................................9

Figure 3.8 : CPAP treatment for OSA ...............................................................13

Figure 4.9 : Babylog CPAP................................................................................14

Figure 4.10 : Nasal CPAP...................................................................................14

Figure 4.11 : The soft, steady jet of air from the CPAP machine (Canadian

Lung Association, 2009).....................................................................................15

Figure 4.12 : Full-face mask...............................................................................17

Figure 4.13 : Mask with nasal pillows................................................................17

Figure 4.14 : Nasal mask....................................................................................17

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List of Tables

Table 1 : Ventilation (SWAN, J. 2006. page 46)..................................................7

Table 2 : comparisons over two time periods(Narendran et al., 2003)......10

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1.0 INTRODUCTION

Babies, who have born early 32 weeks, are called premature babies. After they are born,

babies must breathe continuously to get oxygen. In a premature baby, the part of the centralnervous system (Brain and Spinal cord), that controls breathing is not yet mature enough to

allow nonstop breathing.

When they are first born, many of these premature infants must get help breathing because

their lungs are too immature to allow them to breathe on their own. Continuous positive

airway pressure (CPAP) devises are used to help keeps a preemies lungs open. Therefore,

he/she can breathe; however, the CPAP device does not provide breaths for the baby, so the

baby breathes on his own.

1.1 BACKGROUND OF THE PROBLEM

Continuous positive airway pressure (CPAP) treatment commonly used to treat breathingdisorders of premature infants, including respiratory distress syndrome (RDS) and for patient

who has Obstructive sleep apnoea. CPAP device continuously provides pressurised air or a

mixture of air and oxygen to the entrance of a patients airway via an endotracheal tube

(flexible plastic tube that is put in the mouth or nose) at a pressure elevated above

atmospheric pressure typically in range of 2.2 - 7.35 Hgmm . The positive pressure causes the

gas to flow into the lungs with less effort and prevent the undesirable contracting in alveoli

.The alveoli are tiny air sacs within the lungs where the exchange of oxygen and carbon

dioxide takes place.

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Figure 1.1 : CPAP Treatment (Narendran et al., 2003)


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Over the years, many companies have developed several CPAP machines, which have the

ability to supply the required air mixture at a predetermined pressure and an oxygen

percentage. However, due to their high cost (In local market existing devices cost take around

two million rupees). Therefore, they are in under affordable and are available only in a few of

the main hospitals.

In addition, the existing devices have been designed to operate by wall-mounted air and

oxygen supplies, therefore these devices have to be kept inside an ICU. If the device were

portable, enough so that it could use in an ambulance, the therapy could be followed while

the patient is being carried. Besides, it could be used in normal wards making the ICU vacant

for another patient

Therefore, there is a higher demand for a low cost and portable CPAP device that can be used

in the hospitals in Sri Lanka. The project's goal is to develop a prototype of a low-cost

neonatal CPAP for poor countries that are more affordable to buy own, more easy to use and

locally maintainable.

1.2 OBJECTIVES OF THE PROJECT

Design a low cost CPAP device with the following capabilities

Mix oxygen and air to a given ratio as determined by a physician

Ability to set the flow rate of the mixture up to a limit of 15 litres per minute

Supply the mixture at a pressure of 3 to 5 water centimetres

Give warning if actual flow rate or pressure is outside set limits, the machine

should also stop flow if these values can cause harm to the patient

Has the ability to record the operating parameters over time

The device should be portable enough to be carried in an ambulance

In this literature review report, include concepts and information mainly relating to the

medical background of the project. However, in first few topics gave you a brief introduction

about the human respiratory system, which may be useful to understand the clearly medical

terms and knowledge that are described throughout the report.

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2.0 BASIC OF THE RESPIRATORY SYSTEM

The respiratory system main function is to admittance gases to all body cells; however,

respiratory system facilitates removal of the carbon dioxide. The respiratory system is a

group of organs and tissues. The main parts of this system are the airways, the lungs and

linked blood vessels, and the muscles that enable breathing.

Oxygen is essential for cells, which use this essential substance to release the energy needed

for cellular activities. In addition to supplying oxygen, the respiratory system aids in

removing of carbon dioxide, preventing the toxic build-up of this waste product in body

tissues (A group of connected cells). Day-in and day-out, without the prompt of conscious

thought, the respiratory system carries out its life-sustaining activities.(Swan, 2006)

2.1 RESPIRATORY PROCESS

There are two parts in respiratory process. Which are called Inspiration (inhaling) and

expiration (exhaling). During inspiration, the diaphragm contracts (Figure2.1), moves

downward, and causes the thoracic cavity volume to increase. When the diaphragm relaxes

the thoracic volume, decreases and the lungs partially deflate. This process is called

expiration.

2.1.1 INSPIRATIONIn inspiration, air is moved into the lungs. The rib cage and the diaphragm (Figure 2.1)

control their movements. The diaphragm contracts, this would cause to increase the volume

of the thorax and lungs (West, 2008). Therefore, it is caused to decrease in pressure of lungs

and air will get into the lungs.

3Figure 2.2 : Inspiration (SWAN, J. 2006. Page 42)


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Inhalation is initiated by the diaphragm and supported by the external intercostals muscles.

Normal human resting respirations are 10 to 18 breaths per minute, with a time-period of 2

seconds.(West, 2008)

2.1.2 EXPIRATION

Exhalation is generally a passive process. The lungs have a natural elasticity, so the

diaphragm get relaxes due to elasticity of the muscle tissue and of the lung stroma causes

recoil that returns the lungs to their volume before inspiration (Figure 2.2). They recoil from

the stretch of inhalation; airflows back out until the pressures in the chest and the atmosphere

reach equilibrium. (West, 2008)

2.2 BALANCE BETWEEN INSPIRATION AND EXPIRATION(Swan, 2006)

The tendency of the lungs to expand, called distension, is due to the pulling action applied by

the pleural membranes (any thin layer of connective tissue coating individual cells and organs

of the body). Expansion is also facilitated by the action of surfactant in preventing the

collapse of the alveoli. This distension is force responsible for inspiration. The opposite

tendency is called elasticity or recoil, and is the process by which the lungs return to their size

before inspiration (Figure 2.1 & Figure 2.2). Recoil is due to the elastic stroma (the

connective tissue that provides the framework of an organ) of the lungs and the series elastic

elements of the respiratory muscles, particularly the diaphragm.

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Figure 2.3 : Expiration (SWAN, J. 2006. page 43)


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The diaphragm is a dome-shaped muscle located below your lungs. It separates the chest

cavity from the abdominal cavity. The diaphragm is the main muscle used for breathing.

2.2.1 FUNCTION OF THE ALVEOLI

Alveoli are thin-walled chambers surrounded by capillaries for gas transport

(Figure2.3).There are about 300 million alveoli in the human lung, each about 1/3mm in

diameter (if they are spheres). In elastic fibers, part of the stroma of the lungs, provide

support and elasticity (recoil) for the lungs.(Swan, 2006)

2.3 PRESSURE CHANGE DURING VENTILATION

During inspiration, the pressure inside the lungs (the intrapulmonary pressure) decreases

Hgmm3-to1- compared to the atmosphere (Gauge Pressure).However, this variation can

vary with the depth of inspiration.During expiration, the intrapulmonary pressure increases

Hgmm3to1 ++ compared to the atmosphere. (Swan, 2006)

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Figure 2.4 : Alveoli (SWAN, J. 2006.page 30)

Figure 2.5 : Pressure change during ventilation (Swan, 2006)


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3.0 INTRODUCTION TO CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP)

In modern, mechanical ventilation, systems are used to ventilate patient that have different

kind of respiratory diseases. CPAP machines also one type of ventilation technique fall under

the positive pressure ventilators. Continuous positive airway pressure devices help to breathe,

which patient has respiratory diseases and need help to breathe. CPAP provides backpressure

to prevent lungs from collapsing.

Mainly CPAP are used to help the patient that suffered diseases called Respiratory Distress

Syndrome (RDS) andObstructive Sleep Apnoea (OSA).Here RDS occurs only in babies that

caused by premature born.

3.1 VENTILATION

Ventilation is involved of two parts; inspiration and expiration. Each of these can be

described as being either quiet, the process at rest, or forced, the process when active such as

when exercising. If the volume of the gas increases, its pressure will decrease. If the volume

decreases, its pressure will increase (Boyle's Law). (Swan, 2006) The movement of air in

ventilation occurs because of the pressure gradient produced when the volume of the lungs

increases or decreases. The following table describes the events, which produce this pressure

gradient at different respiratory condition. Which mean either at normal or forced breathing

conditions.

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Ventilators

Positive Pressure

Ventilation

Negative Pressure

Ventilation

CPAP Treatment

OSA

RDS

Figure 3.6 : Mechanical Ventilation


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Table 1 : Ventilation (SWAN, J. 2006. page 46)

Inspiration Expiration

Restful Diaphragm contracts volumes of thorax

and lungs increase, pressures decrease:

air flows inward along pressure gradient

Diaphragm relaxes, volumes of thorax and

lungs decrease, pressures increase: air

flows outward along pressure gradient

Forced Additional muscles help to increase the

volume of the thorax and lungs: scalene,

pectoral is minor, sternocleidomastoid

(is a paired muscle in the superficial

layers of the anterior portion of the

neck. It acts to flex and rotate the head.)

Additional muscles aid in decreasing the

volume of the thorax or in pushing the

diaphragm upward.

3.1.1 MECHANICAL VENTILATION

Mechanical ventilation is a life support treatment. A mechanical ventilator is a machine that

helps people breathe when they are not able to breathe enough on their own. The mechanical

ventilator is also called a ventilator, respirator, or breathing machine

Ventilator machine generates a controlled flow of gas into a patients airways. Oxygen and

air are received from cylinders or wall outlets, the gas is pressure reduced and blended

according to the prescribed inspired oxygen tension (FiO2), accumulated in a receptacle

within the machine, and delivered to the patient using one of many available modes of

ventilation.

Mechanical ventilation is often a life-saving intervention, but carries many potential

complications including pneumothorax, airway injury, alveolar damage, and ventilator-

associated pneumonia(Ohio State University Medical, 2008). For this reason the pressure and

volume of gas used is strictly controlled, and reduced as soon as possible.

It can be used as a short-term measure for the operation or critical illness (setting of an ICU).

It may be used at home or in a nursing institution if patients have chronic diseases that

require long-term ventilator assistance. Mainly ventilators categorised into two types

Negative pressure ventilation

Positive pressure ventilation

In our project of developing continuous positive airway pressure device is fall

under the positive pressure ventilation type.

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3.1.2 NEGATIVE PRESSURE VENTILATION

In this machine, air is withdrawn mechanically to produce a vacuum inside the tank, to create

negative pressure. This negative pressure leads to expansion of the chest, which causes a

decrease in intrapulmonary pressure (pressure within the lungs), and increases flow of

atmospheric air into the lungs. As the vacuum is released, the pressure inside the tank

equalizes to that of the atmospheric pressure, and the elastic coil of the chest and lungs leads

to passive exhalation. However, when the vacuum is created, the abdomen also expands

along with the lung, cutting off venous flow back to the heart, leading to pooling of venous

blood in the lower extremities.(Patrick Neligan. MD University of Pennsylvania, 2009)

3.1.3 POSITIVE PRESSURE VENTILATION

The positive pressure ventilation is that gas flows along a pressure gradient between the

upper airway and the alveoli. The operator determines the magnitude, rate and duration of

flow. Flow is either volume targeted and pressure variable, or pressure target and volume

variable. The pattern of flow may be either sinusoidal (which is normal), decelerating or

constant. Flow is controlled by an array of sensors and microprocessors. Conventionally,

inspiration is active and expiration is passive.(Patrick Neligan. MD University of

Pennsylvania, 2009)

In CPAP device pressure target and volume variable while, the pattern of the flow is constant.

The pressure oscillates aroundzero or atmospheric pressure. The intrapleural (inner surface

of the chest wall) pressureis alwaysnegative compared to the atmosphere. This is necessary

in order to exert a pulling action on the lungs. The pressure varies from about -4 mmHg at the

end of expiration, to -8 mmHg and the end of inspiration. Therefore CPAP device maintain

the 2.2-3.6 mmHg positive pressure level.

3.3 DESEASES THAT ARE USED CPAP TREATMENT

Mainly CPAP treatment are used for following diseases

Respiratory distress syndrome (RDS)

1. Obstructive sleep apnoea (OSA)

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3.3.1 RESPIRATORY DISTRESS SYNDROM (RDS)

About 23,000 babies were born before the 34th week of pregnancy in a year and suffer from

these breathing problems with RDS. lack a protein called surfactant that keeps small air sacs

in the lungs from collapsing.(March of Dimes Foundation, 2009)

Hundreds of thousands of newborns die every year in the world, because they cannot get

enough air into their lungs (respiratory distress). Premature infants lack surfactant (surfactant

is a substance that helps keeps lungs open when breathing) in their lungs, a soap-like coating

that prevents the interior of the alveoli from sticking together. Even if neonates are mature

enough to have the surfactant, infections and TTN (transient tachypnea of the newborn aka

"wet lungs"--fluid in the lungs due to delayed clearance/resorption of fetal lung fluid) lead to

a condition where newborns need respiratory assistance.(Schmid et al., 1976)

3.3.1.1 ROLE OF SURFACTANT

Many babies born prematurely have not yet started making surfactant. Surfactant is a

substance that helps keeps lungs open when breathing.(Stevens, 2009)

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Figure 3.7 : CPAP Treatment for poor baby


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Along with surfactant treatment, babies with RDS may need additional oxygen and

mechanical breathing assistance to keep their lungs expanded. They may need the support of

a ventilator or they may receive treatment called continuous positive airway pressure. CPAP

delivers pressurized air to the babys lungs through small tubes in the babys nose or through

a tube that has been inserted into his windpipe(March of Dimes Foundation, 2009). CPAP

helps a baby breathe, but it does not breathe for him. The sickest babies may need the help of

a ventilator to breathe for them while their lungs mature.

Very sick babies might be put on a high frequency oscillatory ventilator. This ventilator

inflates and deflates babys lungs like a set of billows, the oscillator keeps the lungs open

with a constant positive end-expiratory pressure (PEEP) and vibrates air at a very high rate

(up to 600 times/second). The vibration helps gases to diffuse quickly in and out of babys

airways without need for bellows action, which may damage delicate lung structure.

(Stevens, 2009)

3.3.1.3 CAUSES FOR THE PREMATURE BIRTH(Stevens, 2009)

The latest research suggests that many cases are caused by the bodys natural response to

certain infections, including those involving amniotic fluid and fetal membranes. However, in

about half of all cases of premature birth, providers cannot determine why a woman delivered

prematurely. Any woman can give birth prematurely, but some women are at greater risk than

others are. Researchers have identified some risk factors, but providers still cannot predict

which women will deliver prematurely.

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Three groups of women are at greatest risk for premature birth:

1. Women who have had a previous premature birth

2. Women who are pregnant with twins, triplets or more

3. Women with certain uterine or cervical abnormalities

Certain lifestyle factors may put a woman at greater risk for preterm labor. These include:

Smoking

Drinking alcohol

Using illegal drugs

Exposure to the medication

Lack of social support

Extremely high levels of stress

Certain medical conditions during pregnancy also may increase the likelihood that a woman

will have preterm labor. These include:

Infections (including urinary tract, vaginal, sexually transmitted and other infections)

High blood pressure

Obesity

Clotting disorders

Non-Hispanic black race

Younger than age 17, or older than age 35 (Canadian Lung Association, 2009)

3.3.2 OBSTRUCTIVE SLEEP APNOEA

Air passages of the nose and the throat of some people, becomes blocked or collapse, while

they are sleeping. This airway collapse causes a blockage, which can cause breathing to stop

briefly. When breathing stops for a short time, it is known as apnoea(Ohio State University

Medical, 2008). Apnoea is a serious condition and needs to be treated. CPAP is the most

common treatment for obstructive sleep apnoea. This condition is diagnosed by doing a sleep

study. CPAP is used to keep the airway open while you sleep. A small air blower in the

CPAP machine pushes air through a flexible tube. The tube attaches to a mask that fits over

your nose, or nose and mouth while you sleep (Figure 3.3). The constant flow of air through

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the tubing prevents the air passages in your nose and throat from collapsing so your breathing

does not stop.

Premature babies sometimes stop breathing for 20 seconds or more. This interruption in

breathing is called apnoea, and it may be accompanied by a slow heart rate. Premature babies

are constantly monitored for apnoea. If the baby stops breathing, a nurse stimulates the baby

to start breathing by patting him or touching the soles of his feet.

Nasal CPAP is currently the best treatment for severe obstructive sleep apnoea. CPAP is safe

and effective, even in children. Tissues are prevented from collapsing during sleep, and

apnoea is effectively prevented without surgical intervention. Daytime sleepiness improves or

resolves. Heart function and hypertension also improve.(MedicineNet, 2009)

At first, CPAP patients should be monitored in a sleep lab to determine the appropriate

amount of air pressure for them. The first few nights on CPAP tend to be difficult, with

patients experiencing less sleep. Many patients at first find the mask cumbersome,claustrophobic or embarrassing. CPAP is not a cure and must be used every night for life.

Non-compliant patients experience a full return of obstructive sleep apnoea and related

attribute.(MedicineNet, 2009)

Therefore, this CPAP treatment is used for both diseases called Respiratory Distress

Syndrome, which caused the premature born, and Obstructive Sleep Apnoea.

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Figure 3.8 : CPAP treatment for OSA


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4.0 WHAT IS CPAP WHY CPAP

As described above CPAP is a device that helps to breathe and does not breathe machine for

the patient. CPAP provides backpressure to prevent premature infant lungs from collapsingtreatment is typically necessary for a day or two, after which newborns can breathe on their

own infants with severe respiratory distress, are put on a ventilator without a CPAP machine,

an estimated 30% of the babies with respiratory distress will choke.(Schmid et al., 1976)

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Figure 4.9 : Babylog CPAPFigure 4.10 : Nasal CPAP


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for replacement parts, the provision of training for users, and the demands of a harsh

environment.

The project's goal is to develop a prototype of a low-cost neonatal CPAP for poor countries

that is more affordable to buy more intuitive to use and locally maintainable.

4.3 IMPORTANT OF THE HUMIDIFICATION DURING CPAP

Introduced in 1981, nasal continuous positive airway pressure (nCPAP) therapy has since

become the treatment of choice for obstructive sleep apnoea (OSA). However, nCPAP

therapy may be associated with a number of side effects, which, in some cases, may result in

a considerable decline of treatment compliance. The most common side effect, which occurs

in 3066% of all patients undergoing nCPAP, is upper airway drynests(Wiest et al., 2002).

To deal with this situation, the use of a heated humidifier (HH) system integrated in the tube

system between the CPAP device and the nasal mask has been recommended. Scientific

studies carried out in recent years have shown that dryness of the mouth, nose and throat can

be effectively prevented in this way, thus improving compliance .The question now arises as

to whether general prophylactic use of HH during CPAP treatment may be of benefit to the

patient.(Wiest et al., 2002)

One of the predictors of initial treatment refusal is discomfort during the initiation phase of

CPAP therapy; hence, the initiation phase should be made as comfortable as possible for the

patient. Theoretical benefits of HH use during the initiation phase of CPAP therapy include

improved patient comfort; an improved initial acceptance of the therapy should be the result.

However, before HH can be recommended for prophylactic use in clinical routine, the

hypothesis needs to be tested in clinical trials. Thus, the aim of the present study was to

investigate whether, during the initiation phase of CPAP treatment in the sleep laboratory,

prophylactic HH would result in improved initial patient comfort and acceptance.(Wiest et

al., 2002)

4.4 HOW TO CHOOSE CPAP MASK

The key to using CPAP successfully is a good mask fit. Your mask needs to be comfortable.

When you are selecting a mask, pick one that feels comfortable as soon as you put it on.

There are several kinds of CPAP mask on the market:

Nasal mask

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Masks with nasal pillows or cushions

Full face masks

Masks for children

4.5 BENIFIT OF THE CPAP(Canadian Lung Association, 2009)

Keep your airways open while you sleep

Correct snoring so others in your household can sleep

Improve the quality of your sleep

Relieve symptoms of sleep apnea, such as excessive daytime sleepiness

Decrease or prevent high blood pressure

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ure 4.12 : Full-face mask Figure 4.13 : Mask with nasal pillows

Figure 4.14 : Nasal mask


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4.6 WHAT ARE THE RISK OF CPAP(AMERICAN THORACIC SOCIETY, 2005)

Infections

Feed tube allows germs (bacteria) to get into the lungs more easily. This can

cause an infection like pneumonia

Collapsed lung (pneumothorax)

The lung that is weak can become too full of air and start to leak. The leak lets

air get into the empty space between the lung and the chest wall. Air in this

space takes up room so the lung starts to collapse.

Lung damage

The pressure of putting air into the lungs with a ventilator can damage the

lungs. Doctors try to keep this risk at a minimum by using the lowest amount

of pressure that is needed.

According to the above information, it can be conclude that development of a CPAP is not

easy one. It is needed to consider about the patient safety and comfort ability, while

developing the CPAP for premature infants.

5.0 CONCLUSION

Continuous positive airway pressure (CPAP) devices commonly used to treat breathing

disorders of premature infants, including respiratory distress syndrome (RDS) and for patient

who has Obstructive Sleep Apnoea. CPAP device continuously provides pressurised air or a

mixture of air and oxygen to the entrance of a patients airway via an endotracheal tube

(flexible plastic tube that is put in the mouth or nose) at a pressure elevated above

atmospheric pressure typically in range of 2.2 - 7.35 Hgmm . The positive pressure causes the

gas to flow into the lungs with less effort and prevent the undesirable contracting in alveoli.

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Finally it can be conclude that CPAP devices has been used primarily to treat surfactant

deficiency in preterm infants for much years and still it has been developing. In our project

particularly focuses on its potential role to reduce brawbacks , cost value and make

comfortable one for patient.

Reference

Literature Survey Final Report

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