Respiratory Distress Syndrome of the Newborn



Yüklə 63,71 Kb.
Pdf görüntüsü
tarix06.05.2018
ölçüsü63,71 Kb.
#41728


197

Respiratory Distress 

Syndrome of the Newborn

19

Respiratory distress syndrome (RDS) of the newborn, also known as hyaline 



membrane  disease,  is  a  breathing  disorder  of  premature  babies.  In  healthy 

infants, the alveoli—the small, air-exchanging sacs of the lungs—are coated by 

surfactant,  which  is  a  soap-like  material  produced  in  the  lungs  as  the  fetus 

matures in preparation for birth. If premature newborns have not yet produced 

enough surfactant, they are unable to open their lungs fully to breathe.

Whom does it affect?

Epidemiology, prevalence, economic burden, and vulnerable populations

Respiratory distress syndrome (RDS) affects about 1 percent of newborn infants 

and is the leading cause of death in babies who are born prematurely (1). About 

12 percent of babies born in the United States are preterm, which is higher than 

in other developed countries (2). About 10 percent of premature babies in the 

United States develop RDS each year (3). The risk of RDS rises with increasing 

prematurity. Babies born before 29 weeks of gestation have a 60 percent chance 

of developing RDS (4), but babies born at full term rarely develop this condition. 

Maternal risk factors for preterm birth include previous preterm birth, periodontal 

disease, low maternal body mass, poor prenatal care, poverty, being uninsured, 

and being a member of a minority group

 

(5).



Whitebook_breathing_Ch19.indd   197

6/26/10   12:18:06 AM




Respiratory Distress Syndrome 

Chapter 19

198

Among  premature  babies,  the  risk  of  developing  RDS  increases  with 

 Caucasian race, male sex, an older sibling with RDS, cesarean delivery, perina-

tal asphyxia, and maternal diabetes. 

In 2003, the total number of live births in the United States for all races 

was 4,089,950; about 0.6 percent of newborns had RDS (about 24,000 or 6 per 

1,000  live  births)  (6).  In  2005,  there  were  4,138,000  live  births  in  the  United 

States, and a slightly larger number of babies were affected with RDS because 

the rate of premature births had increased from 11.6 percent to 12.7 percent, 

mainly due to a rise in late preterm births (34 to 36 weeks of gestation) (7). 

Even though the number of RDS cases in the United States is growing, the 

infant mortality rate from RDS has dramatically declined from about 25,000 deaths 

per year in the 1960s to 860 deaths in 2005 (7) because of surfactant replace-

ment therapy. Infant deaths from RDS were 2.6 times greater in African Ameri-

can babies than in Caucasian babies, although Caucasian babies are at a higher 

risk to develop the condition.

In  2001,  hospital  charges  for  a  premature  baby  were  estimated  to  be 

$75,000  (8).  With  approximately  18,000  hospitalizations  each  year  due  to 



0

10

20

30

40

50

60

70

80

90

100

501–600

601–700

701–800

801–900

901–1,000

1,001–1,1001,101–1,2001,201–1,3001,301–1,4001,401–1,500

RDS (%)

Birth Weight (grams)

Respiratory distress syndrome in the United States by birth weight

Incidence of respiratory distress syndrome (RDS) in the United States relative to birth weight, which shows 

it is a disease of premature infants. Horbar JD, Carpenter JH, Kenny M, eds. Vermont Oxford Network 

2002 Very Low Birth Weight Database Summary. Burlington, VT: Vermont Oxford Network; 2003.

Whitebook_breathing_Ch19.indd   198

6/25/10   12:54:41 PM




Chapter 19

 

Respiratory Distress Syndrome

199

RDS,  the  total  cost  of  treating  these  babies  in  the  hospital  is  approximately 

$2.3 billion.

What we are learning about the disease

Pathophysiology, causes: genetic, environment, microbes

Through the ages, infant death has been attributed to an inability of the newborn 

to adapt to life outside the uterus. In the early 20

th

 century, “hyaline membranes” 



CaSe StUdy

In August 1963, First Lady Jacqueline Bouvier Kennedy was hospitalized in 

her 34

th

 week of pregnancy at the Otis Air Force Base Hospital. Her fetus 

was in distress, but labor did not progress. On August 7, she underwent 

a cesarean section to deliver Patrick Bouvier Kennedy, who weighed 

4 pounds, 10.5 ounces (2,112 grams). After delivery, the baby developed 

difficulty breathing, which did not improve despite oxygen therapy. The 

baby was then rushed to Children’s Hospital Boston, a leading center in 

respiratory distress syndrome (RDS). Unfortunately, despite the best 

medical efforts, the baby died two days later. The death of the newborn 

baby devastated the First Family. In the weeks that followed the tragedy, 

the president and his mother-in-law, Janet Auchincloss, feared that 

Jacqueline would have a nervous breakdown, although it was reported that 

this adversity ultimately brought the president and his wife closer together.

Comment

Although RDS affects the infant, in many ways, it takes a greater toll on 

the families. The newborn may be in a neonatal intensive care unit for a 

prolonged period, and the outcome is likely to be death or lifelong 

disability. The emotional, family, and economic stress can be ruinous. The 

story of the Kennedy child gripped the nation and alerted the world to the 

dire consequences of infant RDS. Patrick Kennedy’s obituary in the New 

York Times stated that the only treatment “for a victim of hyaline membrane 



disease is to monitor the infant’s blood chemistry and to try to keep it near 

normal levels. Thus, the battle for the Kennedy baby was lost only because 

medical science has not yet advanced far enough to  accomplish as quickly 

as necessary what the body can do by itself in its own time.”

Whitebook_breathing_Ch19.indd   199

6/25/10   12:54:41 PM



Respiratory Distress Syndrome 

Chapter 19

200

were found during autopsy in the lungs of infants who died shortly after birth, but 

never in stillborns. In the 1920s, Dr. Kurt von Neergaard, a Swiss physiologist, 

postulated the existence of a substance in the lungs that reduces surface ten-

sion, allowing the lungs to open. In the 1950s, Dr. John Clements, a U.S. pulmo-

nary physiologist, showed that this substance was surfactant. Finally, in 1959, 

Drs. Mary Ellen Avery and Jere Mead, both working at Harvard at the time, dem-

onstrated that surfactant was lacking in the lungs of premature babies, which was 

the base cause of the respiratory failure seen in some of these infants (9). 

Further study on infant respiratory distress syndrome (RDS) found that the 

deficiency 

of surfactant was a consequence of either insufficient production by 

the immature lungs or a genetic mutation in one of the surfactant proteins, SP-B. 

The rarer genetic form of the disease is not associated with premature birth and 

occurs in full-term babies (10). 

Surfactant is necessary for the tiny lung alveoli to overcome surface tension 

and remain open. Without adequate surfactant, the pressure exerted trying to 

open these alveoli by either the baby’s desperate breathing or by a mechanical 

ventilator ruptures the alveoli, producing an emphysema-like picture, or pneu-

mothorax, if the air escapes outside the lung and is trapped in the chest wall. 

Extremely premature babies may suffer from bleeding into the brain (intraven-

tricular hemorrhage), sepsis, and other complications of their immature systems, 

including neurological and developmental damage. In survivors, bronchopulmo-

nary dysplasia (a chronic scarring lung disease marked by prolonged oxygen 

need) may develop due to oxygen toxicity and mechanical ventilation. These 

complications  are  related  to  the  severity  of  the  disease,  birth  weight,  and 

 gestational age of the infant. Smaller babies are at greater risk of developing 

bronchopulmonary dysplasia.



how is it prevented, treated, and managed?

Prevention, treatment, prognosis

By far the biggest risk factor for respiratory distress syndrome (RDS) is prematu-

rity. Preventing premature births could nearly eliminate RDS. Several causes of 

premature birth are preventable by good prenatal care. If the birth cannot be 

delayed beyond 34 weeks, the mother may be given corticosteroid therapy before 

birth, which accelerates fetal lung maturation. High-risk and premature infants 

require prompt attention by a pediatric resuscitation team. Healthcare providers 

Whitebook_breathing_Ch19.indd   200

6/25/10   12:54:41 PM



Chapter 19

 

Respiratory Distress Syndrome

201

may deliver the baby and administer surfactant down the infant airways, either as 

soon as the premature baby is born or when RDS is diagnosed. The babies can 

be given respiratory support by mechanical ventilators with  continuous positive 

airway pressure (CPAP) designed to prevent the alveoli from collapsing. 

The use of oxygen has improved the life of many persons with respiratory 

disease. In the 1950s, however, its harmful effects were manifest when  blindness 

occurred in premature infants given pure oxygen. As mechanical ventilation and 



Steve 

Young

Without surfactant, breathing is impossible. Important basic science research led to the 

creation of surfactant replacement therapies that have dramatically improved survival of 

premature babies. However, there are still many mysteries about surfactant, including the 

function of this beautiful lattice-like structure; the colors were added to the squares of the lattice 

to help scientists understand how the lattices might form and work.

Whitebook_breathing_Ch19.indd   201

6/25/10   12:54:45 PM



Respiratory Distress Syndrome 

Chapter 19

202

critical care became more sophisticated in the 1960s and 1970s, neonatal inten-

sive care unit beds became filled with RDS survivors. Although these premature 

infants could be kept alive longer on ventilators, many still died, and those who 

lived often developed bronchopulmonary dysplasia.

One of the greatest breakthroughs in the fight against lung disease was the 

development of surfactant replacement therapy, which saves these premature 

infants from an almost certain death. Its use has led to a dramatic decrease in 

mortality from nearly 100 percent to less than 10 percent. Typically, infants are 

able to breathe more easily within a few hours of receiving surfactant, and com-

plications such as lung rupture are less likely to occur. There is a risk of bleeding 

into the lungs from surfactant treatment, especially in extremely low birth weight 

infants (those weighing less than 1,000 grams). 

In addition, inhaled nitric oxide can improve oxygenation and reduce pulmo-

nary inflammation. When begun soon after birth in these premature infants, nitric 

oxide administration improves the acute disease and also reduces the chance of 

chronic lung disease. As with most drugs, it can also have side effects, including 

an increased risk of bleeding.



are we making a difference? 

Research past, present, and future

Although  earlier  research  defined  the  disease,  the  major  breakthrough  came 

with  the  discovery  that  lack  of  surfactant  was  the  main  defect.  Studying  the 

physiology  of  lungs  under  different  conditions  showed  how  critical  surfactant 

was for breathing. Further research into the production, function, and composi-

tion of surfactant produced a deeper understanding of respiratory distress syn-

drome (RDS). The race was then on to develop surfactant replacement therapy. 

Both synthetic and animal-derived substances as well as components of surfac-

tant  were  investigated  as  possible  therapies.  By  1987,  clinical  studies  with 

 surfactant therapy had begun in Japan, and studies in animal models of RDS 

were under way in the United States. The use of surfactant derived from calf 

lung produced gratifying results when given immediately after birth. There were 

concerns that disease transmission could occur from treating newborns with an 

animal-derived product, but fortunately this has not been reported. 

Currently, all of the surfactant replacement therapies in use in the United 

States  are  animal  derived.  The  surfactant  replacement  material  is  not  as 

Whitebook_breathing_Ch19.indd   202

6/25/10   12:54:45 PM




Chapter 19

 

Respiratory Distress Syndrome

203

 complete as natural human surfactant, and it is not effective in treating the type 

of RDS caused by the genetic mutation in SP-B, but for most cases, it has been 

wonderfully successful.

Despite  the  success  of  surfactant  replacement  in  improving  survival 

of  premature babies with RDS, 5,000 to 10,000 newborns still develop bron-

chopulmonary dysplasia or other forms of chronic lung disease. The problem is 

most severe for the smallest babies in the extremely low birth weight group (500 

to 699 grams), up to 85 percent of whom develop this complication. Preterm 

infants  with  bronchopulmonary  dysplasia  are  at  increased  risk  of  death, 

 re- hospitalization, and chronic and acute respiratory symptoms requiring ther-

apy as compared with full-term infants. Therefore, recent research, both basic 

and clinical, has focused on efforts to prevent this complication. Clinical trials 

testing the usefulness of continuous nitric oxide inhalation therapy after birth 

and  of  repeated  doses  of  surfactant  to  reduce  the  incidence  and  severity  of 

bronchopulmonary dysplasia are ongoing.

Although there has been great reduction in the mortality and morbidity from 

RDS, the disease itself continues to increase with the rising rates of premature 



0

10

20

30

40

50

60

70

80

90

100

501–600

601–700

701–800

801–900

901–1,000

1,001–1,1001,101–1,2001,201–1,3001,301–1,4001,401–1,500

Old a

t 36 W

eek

s (%)

Birth Weight (grams)

Chronic lung disease by birth weight

Incidence of bronchopulmonary dysplasia (BPD), defined as oxygen use at 36 weeks corrected postnatal 

age in premature babies. Horbar JD, Carpenter JH, Kenny M, eds. Vermont Oxford Network 2002 Very 

Low Birth Weight Database Summary. Burlington, VT: Vermont Oxford Network; 2003.

Whitebook_breathing_Ch19.indd   203

6/25/10   12:54:46 PM




Respiratory Distress Syndrome 

Chapter 19

204

births. Strategies, such as giving continuous positive airway pressure (CPAP), 

ventilating babies without intubation, and nitric oxide therapy without mechani-

cal ventilation, are being tested to prevent complications of RDS.

Nutrition is important for normal lung development and maturation. Several 

studies have shown that poor nutrition (specifically, a lack of protein) after birth 

may increase risk of lung injury that can lead to bronchopulmonary dysplasia. 

Vitamin A,  a  nutrient  important  for  cell  growth,  has  been  shown  to  decrease 

bronchopulmonary dysplasia in some studies. Other nutrients may provide pre-

mature infants with added protection against this condition. 

Surfactant  therapy  and  other  medical  and  critical  care  advances  have 

increased survival among extremely low birth weight infants. These advances 

have  presented  additional  challenges  because  these  extremely  premature 

babies often survive with residual long-term complications of RDS. If complica-

tions during pregnancy indicate that a premature birth is likely, obstetricians can 

test the amniotic fluid for surfactant in order to track fetal lung development. 

Several tests are available that correlate with the production of surfactant.

What we need to cure or eliminate respiratory distress syndrome  

of  the newborn

Respiratory  distress  syndrome  (RDS)  can  be  cured  but  not  eliminated.  The 

defect has been discovered. A treatment has been developed, and thousands of 

lives have been saved. Despite this, newborns still develop bronchopulmonary 

dysplasia. Part of the problem is that surfactant replacement therapy and other 

medical  and  critical  care  advances  have  allowed  the  survival  of  extremely 

 premature infants, who may later have residual long-term complications of RDS. 

Preventing prematurity is probably now the most important factor in eliminating 

RDS. Understanding of and advancements in nutrition and the delivery of critical 

care  medicine  to  newborns  will  also  improve  the  outcome  of  those  with  this 

condition.

Whitebook_breathing_Ch19.indd   204

6/25/10   12:54:46 PM



Chapter 19

 

Respiratory Distress Syndrome

205

references 

  1.  Rodriguez RJ, Martin RJ, Fanaroff AA. Respiratory distress syndrome and its management. 

In: Fanaroff AA, Martin RJ, eds. Fanaroff and Martin’s Neonatal-Perinatal Medicine: 

Diseases of the Fetus and Infant. 7th ed. St. Louis, MO: Mosby; 2002:1001–1011. 

  2.  Goldenberg RL, Culhane JF, Iams JD, Romero R. Epidemiology and causes of preterm 

birth. Lancet 2008;371:75–84.

  3.  National Heart, Lung, and Blood Institute Web site. What is respiratory distress syndrome? 

Available at: 

http://www.nhlbi.nih.gov/health/dci/Diseases/rds/rds_all.html

. Accessed 

January 21, 2010.

  4.  Robertson PA, Sniderman SH, Laros RK Jr, Cowan R, Heilbron D, Goldenberg RL, Iams 

JD, Creasy RK. Neonatal morbidity according to gestational age and birth weight from five

 

tertiary care centers in the United States, 1983 through 1986. Am J Obstet Gynecol 



1992;166:1629–1641.

  5.  Angus DC, Linde-Zwirble WT, Clermont G, Griffin MF, Clark RH. Epidemiology of neonatal 

respiratory failure in the United States: projections from California and New York.  

Am J Respir Crit Care Med 2001;164:1154–1160.

  6.  Centers for Disease Control and Prevention Web site. National Center for Health Statistics. 

Available at: 

http://www.cdc.gov/nchs

. Accessed January 21, 2010.

  7.  American Lung Association Web site. Available at: http://www.lungusa.org. Accessed 

January 21, 2010.

  8.  March of Dimes Web site. Premature birth. Available at: 

http://www.marchofdimes.com/ 

21209_11560.asp

. Accessed January 21, 2010.

  9.  Halliday HL. Surfactants: past, present and future. J Perinatol 2008;28:S47–S56.

10.  Nkadi PO, Merritt TA, Pillers DA. An overview of pulmonary surfactant in the neonate: 

genetics, metabolism, and the role of surfactant in health and disease. Mol Genet Metab 

2009;97:95–101.

Web sites of interest

National Heart, Lung, and Blood Institute 

Diseases and Conditions Index 

www.nhlbi.nih.gov/health/dci/Diseases/rds/rds_all.html

Centers for Disease Control and Prevention 

National Center for Health Statistics 

www.cdc.gov/nchs

American Lung Association 

www.lungusa.org

Whitebook_breathing_Ch19.indd   205



6/25/10   12:54:46 PM


Yüklə 63,71 Kb.

Dostları ilə paylaş:




Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©genderi.org 2023
rəhbərliyinə müraciət

    Ana səhifə