Respiratory distress syndrome RDS is a common problem in premature babies. It causes babies to need extra oxygen and help with breathing. The course of illness with RDS depends on:. RDS typically gets worse over the first 2 to 3 days. It then gets better with treatment.
Each SP protein has distinct functions, which act synergistically to keep an interface rich in DPPC during lung's expansion and contraction. This can lead to increased acid durfectant the blood acidosis. In a Fetus surfectant by Choukroun et al. Surfactant caused a transitional decrease in oscillatory volume but Feyus not alter its regional distribution. Double-blind, Fetus surfectant, placebo-controlled Canadian multicenter trial of two doses of synthetic surfactant or air placebo in infants weighing to grams with respiratory distress syndrome. Bronchoalveolar lavage surfactant protein a, B, and d concentrations in preterm infants ventilated for respiratory distress syndrome receiving natural and synthetic surfactants.
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Learn about surfactant, a substance that occurs in the lungs and helps keep them open.
- Aspects of pulmonary surfactant are reviewed from a biochemical perspective.
- Lung surfactants are made from animal lung extract and contain phospholipids.
- Related to surfactant: emulsifier , Pulmonary surfactant.
- Surfactant is a complex substance that prevents the collapse of alveoli in the lungs.
- Surfactants are compounds that lower the surface tension or interfacial tension between two liquids, between a gas and a liquid, or between a liquid and a solid.
Respiratory distress syndrome RDS is a common problem in premature babies. It causes babies to need extra oxygen and help with breathing. The course of illness with RDS depends on:.
RDS typically gets worse over the first 2 to 3 days. It then gets better with treatment. RDS occurs when there is not enough surfactant in the lungs. Surfactant is a liquid made by the lungs that keeps the airways alveoli open.
This liquid makes it possible for babies to breathe in air after delivery. An unborn baby starts to make surfactant at about 26 weeks of pregnancy. If a baby is premature born before 37 weeks of pregnancy , he or she may not have made enough surfactant yet.
When there is not enough surfactant, the tiny alveoli collapse with each breath. As the alveoli collapse, damaged cells collect in the airways. They further affect breathing. The baby has to work harder and harder to breathe trying to reinflate the collapsed airways. As the baby's lung function gets worse, the baby takes in less oxygen.
More carbon dioxide builds up in the blood. This can lead to increased acid in the blood acidosis. This condition can affect other body organs. Without treatment, the baby becomes exhausted trying to breathe and over time gives up. A ventilator must do the work of breathing instead. RDS occurs most often in babies born before the 28th week of pregnancy. Some premature babies get RDS severe enough to need a breathing machine ventilator. The more premature the baby, the higher the risk and the more severe the RDS.
Most babies with RDS are premature. But other things can raise the risk of getting the disease. These include:. C-section Cesarean delivery, especially without labor.
Going through labor helps babies' lungs become ready to breathe air. The mother has diabetes a baby with too much insulin in his or her body can delay making surfactant. The symptoms of RDS usually get worse by the third day. When a baby gets better, he or she needs less oxygen and mechanical help to breathe. These can point to a baby's need for help with breathing.
Chest X-rays of the lungs. X-rays make images of bones and organs. Blood gas tests. These measure the amount of oxygen, carbon dioxide and acid in the blood. They may show low oxygen and higher amounts of carbon dioxide. This test is a type of ultrasound that looks at the structure of the heart and how it is working. The test is sometimes used to rule out heart problems that might cause symptoms similar to RDS.
It will also show whether a PDA may be making the problem worse. It will also depend on how severe the condition is. Continuous positive airway pressure CPAP. This is a breathing machine that pushes a continuous flow of air or oxygen to the airways. It helps keep tiny air passages in the lungs open. Artificial surfactant. This helps the most if it is started in the first 6 hours of birth.
Surfactant replacement may help make RDS less serious. It is given as preventive treatment for some babies at very high risk for RDS. For others who become sick after birth, it is used as a rescue method. Surfactant is a liquid given through the breathing tube. Babies sometimes have complications from RDS treatment. As with any disease, more severe cases often have greater risks for complications.
Some complications of RDS include:. Lungs leak air into the chest, the sac around the heart, or elsewhere in the chest. Preventing a premature birth is the main way to prevent RDS. These medicines may greatly lower the risk and severity of RDS in the baby. These steroids are often given between 24 and 34 weeks of pregnancy to women at risk of early delivery. They may sometimes be given up to 37 weeks. But if the delivery is very quick or unexpected, there may not be time to give the steroids.
Or they may not have a chance to start working. It can cause babies to need extra oxygen and help with breathing. RDS occurs most often in babies born before the 28th week of pregnancy and can be a problem for babies born before 37 weeks of pregnancy.
At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.
Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are. Know what to expect if your child does not take the medicine or have the test or procedure. If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
This is important if your child becomes ill and you have questions or need advice. Search Encyclopedia. What is respiratory distress syndrome in premature babies? The course of illness with RDS depends on: The size and gestational age of your baby How serious the illness is Whether your baby has an infection Whether your baby has a heart defect called patent ductus arteriosus Whether your baby needs a machine to help him or her breathe ventilator RDS typically gets worse over the first 2 to 3 days.
What causes RDS in premature babies? Which premature babies are at risk for RDS? These include: The baby is a boy or is white The baby has a sibling born with RDS C-section Cesarean delivery, especially without labor. These are the most common symptoms of RDS: Breathing problems at birth that get worse Blue skin color cyanosis Flaring nostrils Rapid breathing Grunting sounds with breathing Ribs and breastbone pulling in when the baby breathes chest retractions The symptoms of RDS usually get worse by the third day.
The symptoms of RDS may look like other health conditions. How is RDS in premature babies diagnosed? How is RDS in premature babies treated? Treatment for RDS may include: Placing a breathing tube into your baby's windpipe trachea Having a ventilator breathe for the baby Extra oxygen supplemental oxygen Continuous positive airway pressure CPAP. Medicines to help calm the baby and ease pain during treatment What are possible complications of RDS in premature babies?
Some complications of RDS include: Lungs leak air into the chest, the sac around the heart, or elsewhere in the chest Chronic lung disease bronchopulmonary dysplasia How can RDS in premature babies be prevented?
Treatment may include extra oxygen, surfactant replacement, and medicines. Before your visit, write down questions you want answered. Know why a test or procedure is recommended and what the results could mean.
Surfactants and Interfacial Phenomena 4th ed. Premature science and immature lungs. Detergents have also been used to decellularise organs. Absence of phosphatidylglycerol PG in respiratory distress syndrome in the newborn. Surfaxin Pro Generic name: lucinactant.
Fetus surfectant. surfactant
Comparison of occurrence, composition, and metabolism in surfactant and residual lung fractions. Isolation and characterization of a sulfated glyceroglucolipid from alveolar lavage of rabbit. Eur J Biochem. The neutral glyceroglucolipids of alveolar lavage from rabbit. Disaturated lecithin concentration of rabbit tissues.
Surface tension studies of phosphatidyl glycerol isolated from the lungs of beagle dogs. Surface properties of binary mixtures of some pulmonary surfactant components.
Pulmonary surface film stability and composition. Dry artificial lung surfactant and its effect on very premature babies. Physicochemical properties of dipalmitoyl phosphatidylcholine after interaction with an apolipoprotein of pulmonary surfactant. Artificial surfactant to prevent and treat neonatal respiratory distress syndrome.
Surfactant substitution; experimental models and clinical applications. Evidence for lipid synthesis by the dihydroxyacetone phosphate pathway in rabbit lung subcellular fractions. J Lab Clin Med. Biosynthesis of dipalmitoyl-sn-glycerophosphocholine by adenoma alveolar type II cells. Arch Biochem Biophys.
Importance of the acyl dihydroxyacetone phosphate pathway in the synthesis of phosphatidylglycerol and phosphatidylcholine in alveolar type II cells. J Biol Chem. Microsomal sn-glycerol 3-phosphate and dihydroxyacetone phosphate acyltransferase activities from liver and other tissues.
Evidence for a single enzyme catalizing both reactions. Glycerol kinase activity in adenoma alveolar type II cells. FEBS Lett. Fatty acid synthesis in the perfused rat lung. Evidence for the synthesis of lung surfactant dipalmitoyl phosphatidylcholine by a "remodeling" mechanism. Biochem Biophys Res Commun. Phospholipase A2 in rat-lung microsomes: substrate specificity towards endogenous phosphatidylcholines.
Synthesis of phosphatidylcholine and phosphatidylglycerol by alveolar type II cells in primary culture. Rate-limiting steps in the cytidine pathway for the synthesis of phosphatidylcholine and phosphatidylethanolamine.
Control of phosphatidylcholine synthesis and the regulatory role of choline kinase in rat liver. Evidence from essential-fatty acid-deficient rats. Glycerolipid formation from sn-glycerolphosphate by rat liver cell fractions. The role of phosphatidate phosphohydrolase. Regulation of de novo phosphatidylcholine synthesis in rat intestine. The involvement of phosphatidate phosphohydrolase and phospholipase A activities in the control of hepatic glycerolipid synthesis. Effects of acute feeding with glucose, fructose, sorbitol, glycerol and ethanol.
Induction of choline phosphotransferase and lecithin synthesis in the fetal lung by corticosteroids. Effects of betamethasone on phospholipid content, composition and biosynthesis in the fetal rabbit lung. Fetal lung maturation.
Phosphatidic acid phosphohydrolase in rabbit lung. Gynecol Invest. Characterization of phosphatidate phosphohydrolase activity associated with isolated lamellar bodies.
Corticosteroid induction of phosphatidic acid phosphatase in fetal rabbit lung. Pulmonary phosphatidic acid phosphatase. Properties of membrane-bound phosphatidate-dependent phosphatidic acid phosphatase in rat lung. Choline phosphokinase, phosphorylcholine cytidyltransferase and CDP-choline: 1,2-diglyceride cholinephosphotransferase activity in developing rat lung.
Tohoku J Exp Med. Fetal lung development and the influence of glucocorticoids on pulmonary surfactant. J Steroid Biochem. Development of glycogen and phospholipid metabolism in fetal and newborn rat lung. The enzymes of phosphatidylcholine biosynthesis in the fetal mouse lung. Effects of dexamethasone. Stimulation of surfactant production by oxytocin-induced labor in the rabbit.
J Clin Invest. Phospholipid content, composition and biosynthesis during fetal lung development in the rabbit. Activity and properties of CTP: cholinephosphate cytidylyltransferase in adult and fetal rat lung. Fetal lung in organ culture. Comparison of dexamethasone, thyroxine, and methylxanthines. Influence of sex hormones on lung maturation in the fetal rabbit.
Studies on pulmonary surfactant. Effects of cortisol administration to fetal rabbits on lung phospholipid content, composition and biosynthesis. Stimulation of phosphatidylcholine synthesis by 17 beta-estradiol in fetal rabbit lung.
Hormonal induction of pulmonary maturation in the rabbit fetus: effects of maternal treatment with estradiol beta on th endogenous levels of cholinephosphate, CDP-choline and phosphatidylcholine. Fetal lung development. Current concepts. Pediatr Clin North Am. Biochemical development of surface activity in mammalian lung.
Pulmonary lecithin synthesis in the human fetus and newborn and etiology of the respiratory distress syndrome. Pediatr Res. Isolation and characterization of lipid N-methylrtansferase from dog lung. The biochemical development of surface activity in mammalian lung.
The biosynthesis of phospholipids in the lung of the developing rabbit fetus and newborn. Comparison of the composition and surface activity of "alveolar" and whole lung lipids in the dog.
The choline incorporation pathway: primary mechanism for de novo lecithin synthesis in fetal primate lung. Studies on the biosynthesis of pulmonary surfactant. The role of the methylation pathway of phosphatidylcholine biosynthesis in primate and non-primate lung. Clin Chim Acta. Role of myo-inositol in the synthesis of phosphatidylglycerol and phosphatidylinositol in the lung.
Selective utilization of endogenous unsaturated phosphatidylcholines and diacylglycerols by cholinephosphotransferase of mouse lung microsomes. Some studies on the biosynthesis of the molecular species of phosphatidylcholine from rat lung and phosphatidylcholine and phosphatidylethanolamine from rat liver. Cholinephosphotransferase in rat lung. The in vitro synthesis of dipalmitoylphosphatidylcholine from dipalmitoylglycerol. Synthesis of disaturated phosphatidylcholine by cholinephosphotransferase in rat lung microsomes.
Utilization of disaturated and unsaturated phosphatidylcholine and diacylglycerols by cholinephosphotransferase in rat lung microsomes. The action of lung lysosomal phospholipases on dipalmitoyl phosphatidylcholine and its significance for the synthesis of pulmonary surfactant. The formation of lecithin from lysolecithin in rat lung supernatant. Studies on the biosynthetic pathways of molecular species of lecithin by rat lung slices. Studies on the biosynthesis of disaturated lecithin of the lung: the importance of the lysolecithin pathway.
Acyltransferase activities in rat lung microsomes. Lysophospholipase and lysophosphatidylcholine:lysophosphatidylcholine transacylase from rat lung: evidence for a single enzyme and some aspects of its specificity.
Subcellular site and mechanism of synthesis of disaturated phosphatidylcholine in alveolar type II cell adenomas. Biosynthesis of pulmonary surfactant: comparison of 1-palmitoyl-sn-glycerophosphocholine and palmitate as precursors of dipalmitoyl-sn-glycerophosphocholine in adenoma alveolar type II cells. Lysolecithin acyltransferase and lysolecithin: lysolecithin acyltransferase in adult rat lung alveolar type II epithelial cells. Differentiation between acyl coenzyme A:lysophosphatidylcholine acyltransferase and lysophosphatidylcholine: lysophosphatidylcholine transacylase in the synthesis of dipalmitoylphosphatidylcholine in rat lung.
Does de novo synthesis of lysophosphatidylcholine occur in rat lung microsomes? Biosynthesis of dipalmitoyllecithin by the rabbit lung. Can J Biochem. Phospholipid composition and acyltransferase activity of lamellar bodies isolated from rat lung.
The cellular origin of pulmonary surfactant. Lab Invest. Role of lamellar bodies in the biosynthesis of phosphatidylcholine in mouse lung. Lung lamellar bodies lack certain key enzymes of phospholipid metabolism. Transfer of phospholipids between subcellular fractions of the lung.
Lung phosphatidylcholine transfer in six vertebrate species. Correlations with surfactant parameters. A unique phosphatidylcholine exchange protein isolated from sheep lung. Phospholipid exchange between subcellular organelles of rabbit lung.
Protein-catalyzed transfer of phosphatidylglycerol by sheep lung soluble fraction. Phospholipid transfer proteins in rat lung. Identification of a protein specific for phosphatidylglycerol. Phospholipid-transfer activity in type II cells isolated from adult rat lung. Alveolar lavage and lavaged lung tissue phosphatidylcholine composition during fetal rabbit development.
Control of flow of fetal lung fluid at the laryngeal outlet. Respir Physiol. Diagnosis of the respiratory distress syndrome by amniocentesis. Am J Obstet Gynecol. The lung profile. Complicated pregnancy. Normal pregnancy. Saturated phosphatidylcholine in amniotic fluid and prediction of the respiratory-distress syndrome.
N Engl J Med. Phosphatidylinositol and phosphatidylglycerol in amniotic fluid: indices of lung maturity. Absence of phosphatidylglycerol PG in respiratory distress syndrome in the newborn. Study of the minor surfactant phospholipids in newborns. Possible modifier of surfactant function. Incorporation of palmitate, glucose and choline into lecithin by fetal and newborn lamb lung.
Changes in the structural and metabolic heterogeneity of phosphatidylcholines in the developing rat lung. Phospholipid metabolism in the liver and lung of rats during development.
Biosynthesis of phosphatidyl choline during prenatal development of the rat lung. Fetal rhesus monkey lung development: lobar differences and discordances between stability and distensibility.
Phosphatidylcholine-lysophosphatidylcholine cycle pathway enzymes in rabbit lung. Marked differences in the effect of gestational age on activity compared to the CDP-choline pathway. The enzymes of lecithin bio-synthesis in human newborn lungs. Choline kinase.
Biol Neonate. Choline kinase and choline phosphotransferase in developing fetal rat lung. Comparison of the phospholipid requirements and molecular form of CTP : phosphocholine cytidylyltransferase from rat lung, kidney, brain and liver.
The role of phosphatidylglycerol in the activation of CTP:phosphocholine cytidylyltransferase from rat lung. Phosphatidate phosphatase: activity and properties in fetal and adult rat lung. Pulmonary phosphatidic acid phosphohydrolase. Developmental patterns in rat lung. Developmental patterns in rabbit lung. Phosphatidate phosphohydrolase activity in porcine pulmonary surfactant.
Fetal lung maturation IV: the release of phosphatidic acid phosphohydrolase and phospholipids into the human amniotic fluid. Fetal lung maturatio. Obstet Gynecol. The measurement of phosphatidate phosphohydrolase in human amniotic fluid. Properties of an acid phosphatase in pulmonary surfactant.
Formation of disaturated lecithin through the lysolecithin pathway in the lung of the developing rabbit. Activity of cholinephosphotransferase, lysolecithin: lysolecithin acyltransferase and lysolecithin acyltransferase in the developing mouse lung.
Enzyme activities related to fatty acid synthesis in developing mammalian lung. Fatty acid synthesis in fetal lung. Lipoprotein lipase activity and blood triglyceride levels in fetal and newborn rats. Formation of acidic phospholipids in rabbit lung during perinatal development. Changes in CTP:phosphatidate cytidylyltransferase activity during rabbit lung development.
Coordinate increases in the enzyme activities responsible for phosphatidylglycerol synthesis and CTP:cholinephosphate cytidylyltransferase activity in developing rat lung. Optimal assay and subcellular location of phosphatidylglycerol synthesis in lung. Dev Biol. Morphologic development of fetal rabbit lung and its acceleration with cortisol. Am J Pathol. The influence of hormones on the biochemical development of fetal rat lung in organ culture.
Effects of estrogen on fetal rabbit lung maturation: morphological and biochemical studies. Association between maternal diabetes and the respiratory-distress syndrome in the newborn. Accelerated appearance of pulmonary surfactant in the fetal rabbit. J Appl Physiol. Lung phosphatidylcholine synthesis and cholinephosphotransferase activity in anencephalic rat fetuses with corticosteroid deficiency.
Acceleration of appearance of pulmonary surfactant in the fetal lamb by administration of corticosteroids.
Surfactant in the lung and tracheal fluid of the fetal lamb and acceleration of its appearance by dexamethasone. Maternal betamethasone and fetal growth and development in the monkey. Response of immature baboon fetal lung to intra-amniotic betamethasone. Effect of cortisol on human fetal lung in organ culture: a biochemical, electron-microscopic and autoradiographic study. Cell Tissue Res. A controlled trial of antepartum glucocorticoid treatment for prevention of the respiratory distress syndrome in premature infants.
Factors affecting lecithin synthesis by fetal lung cells in culture. The effect of thyroxine on the maturation of fetal rabbit lungs. Enhancement of fetal lung maturity by intra-amniotic administration of thyroid hormone. Thyrotropin-releasing hormone increases the amount of surfactant in lung lavage from fetal rabbits. Stimulation of fetal lung surfactant production by administration of 17beta-estradiol to the maternal rabbit.
Human amniotic fluid lecithin-sphingomyelin ratio changes with estrogen or glucocorticoid treatment. The effect of prolactin on the lecithin content of fetal rabbit lung.
The effects of ACTH on lung maturation in fetal lambs. Effect of epidermal growth factor on lung maturation in fetal rabbits. Effects of epidermal growth factor on lung maturation in fetal lambs. Lung maturation in the fetal rat: acceleration by injection of fibroblast-pneumonocyte factor.
Effects of cortisol and aminophylline upon survival, pulmonary mechanics, and secreted phosphatidyl choline of prematurely delivered rabbits. Acceleration of fetal lung maturation by aminophyllin in pregnant rabbits. Aminophylline stimulates the incorporation of choline into phospholipid in explants of fetal rat lung in organ culture.
Role of autonomic nervous system controlling surface tension in fetal rabbit lungs. Effect of oxotremorine and epinephrine on lung surfactant secretion in neonatal rabbits.
Antepartum administration of terbutaline and the incidence of hyaline membrane disease in preterm infants. Acta Obstet Gynecol Scand. Reduced surface tension in lungs of fetal rabbits injected with pilocarpine. Increased synthesis of phosphatidylcholine by rat lung following premature birth. The relationship between premature rupture of the membranes and the respiratory distress syndrome. An update and plan of management. Prolonged rupture of fetal membranes and decreased frequency of respiratory distress syndrome and patent ductus arteriosus in preterm infants.
The effect of labor on surfactant secretion in newborn rabbit lung slices. Risk of respiratory distress syndrome related to gestational age, route of delivery, and maternal diabetes.
Br J Obstet Gynaecol. Premature delivery of foetal lambs infused with glucocorticoids. J Endocrinol. Accelerated appearance of osmiophilic bodies in fetal lungs following steroid injection.
Regulation of fetal lung phosphatidyl choline synthesis by cortisol: role of glycogen and glucose. Cortisol induction of pulmonary maturation in the rabbit foetus. Its effects on enzymes related to phospholipid biosynthesis and on marker enzymes for subcellular organelles. Stimualtion of glycerolphosphate phosphatidyltransferase activity in fetal rabbit lung by cortisol administration. Effect of hydrocortisone on the metabolism of phosphatidylcholine in maternal and fetal rabbit lungs and livers.
Insulin antagonism of dexamethasone-induced stimulation of cholinephosphate cytidylyltransferase in fetal rat lung in organ culture.
Lipoprotein lipase in rat lung. Effect of dexamethasone. Regulation of phosphatidylcholine biosynthesis in cultured chick embryonic muscle treated with phospholipase C. Phosphatidylcholine biosynthesis in isolated hamster heart. Effects of cortisol and thyroxine on phosphatidylcholine and phosphatidylglycerol synthesis by adult rat lung alveolar type II cells in primary culture.
Glucocorticoid receptors and the role of glucocorticoids in fetal lung development. Glucocorticoid receptors in lung. Specific binding of glucocorticoids to cytoplasmic components of rabbit fetal lung.
Glucocorticoid binding by isolated lung cells. Effect of metopirone on the synthesis of lung surfactant in does and fetal rabbits. Use of prenatal glucocorticoid therapy to prevent respiratory distress syndrome. A supporting view. Am J Dis Child. In preparation for breathing air, fetuses begin making surfactant while still in the womb. Babies that are born very prematurely often lack adequate surfactant and must receive surfactant replacement therapy immediately after birth in order to breathe.
Babies are considered premature if they are born before 37 weeks gestation. Fetuses begin to produce surfactant between weeks 24 and By about 35 weeks, most babies have enough naturally produced surfactant to keep the alveoli from collapsing.
Babies born before 35 weeks, especially those born very prematurely before 30 weeks , are likely to need surfactant replacement therapy. Over half the babies born before 28 weeks gestation need this treatment, while about one-third born between 32 and 36 weeks need supplemental surfactant. Some very premature infants may also need to be placed on a mechanical ventilator. The lungs consist of spongy tissue filled with air spaces called alveoli. In the alveoli, oxygen is taken up by the blood and carbon dioxide , a waste product of cellular metabolism, is released and exhaled.
For efficient oxygen- carbon dioxide exchange to occur, the surface area of the alveoli must be as large as possible. Under normal conditions, when a person exhales, the alveoli would collapse into each other and form larger air sacs with less surface area. Surfactant prevents this collapse by reducing the surface tension of the fluids that line the lungs and helping to equalize the pressures between large and small air spaces.
Surface tension is a measure of the attraction molecules of a fluid have for each other. The attractive force pulls fluids into a shape with the smallest surface area. This is why a drop of water on a flat surface is rounded rather than flat. If the surface tension is lowered, the attraction among molecules of the fluid is decreased and the surface area of the fluid increases. For example, if a drop of detergent is added to a drop of water, the detergent reduces the surface tension and the drop of water flattens out.
In the lungs, surfactant reduces the surface tension and helps to maximize the surface area available for gas exchange. Without adequate surfactant, a baby works much harder to breathe, becomes exhausted, and does not get enough oxygen.
Babies that do not have enough surfactant to breathe normally at birth are said to have infant respiratory distress syndrome RDS or hyaline membrane disease HMD. Babies with RDS are given replacement surfactant as soon as possible within the first six hours after birth.
Manufactured surfactant is a white powder that is mixed with sterile water. It is given through a breathing tube endotracheal tube that is inserted in the baby's lungs. Multiple doses are usually required. Surfactant replacement therapy continues until the baby's lungs have matured enough to make surfactant on their own. Some very premature babies are also put on mechanical respirators to help them breathe.
This therapy is expensive, but it is normally covered by insurance. The administration of surfactant is often a neonatal emergency. The only way to prevent the need for surfactant replacement therapy is to prevent a premature birth.
Mothers who are at known high risk to deliver prematurely are given drugs called corticosteroids toward the end of the pregnancy that stimulate the lungs of the fetus to mature and begin producing surfactant sooner. This helps reduce the need for surfactant replacement therapy. Although babies of all races may be born prematurely, prematurity is more common if the mother is diabetic, is carrying multiple fetuses, or has delivered a previous premature baby.
The decision to use surfactant replacement therapy is based on the condition of the baby, its blood oxygen level, and degree of respiratory distress. Babies receiving surfactant therapy are normally cared for by a neonatologist, a pediatrician that specializes in newborn care. Premature newborns often have other health problems in addition to RDS. Aftercare varies depending on their other health risks. Delivery of surfactant requires inserting a breathing tube into the baby's lungs.
Complications of this therapy include air leaking into the area between the chest wall and the lungs and air leaking into the sac around the heart.
Some infants also develop chronic lung disease. Normally surfactant replacement therapy keeps the infant alive until the lungs start producing their own surfactant. Surfactant replacement therapy is very effective if begun within six hours after birth. When it fails, death may result. Doctors Lounge, The. Lucile Packard Children's Hospital at Stanford. Pramanik, Arun.
Pulmonary surfactant is a surface-active lipoprotein complex phospholipoprotein formed by type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions. By adsorbing to the air-water interface of alveoli , with hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of surfactant, dipalmitoylphosphatidylcholine DPPC , reduces surface tension.
As a medication, pulmonary surfactant is on the WHO Model List of Essential Medicines , the most important medications needed in a basic health system.
Alveoli can be compared to gas in water, as the alveoli are wet and surround a central air space. The surface tension acts at the air-water interface and tends to make the bubble smaller by decreasing the surface area of the interface.
Compliance is the ability of lungs and thorax to expand. Lung compliance is defined as the volume change per unit of pressure change across the lung. This difference in inflation and deflation volumes at a given pressure is called hysteresis and is due to the air-water surface tension that occurs at the beginning of inflation. However, surfactant decreases the alveolar surface tension , as seen in cases of premature infants suffering from infant respiratory distress syndrome.
Pulmonary surfactant thus greatly reduces surface tension , increasing compliance allowing the lung to inflate much more easily, thereby reducing the work of breathing. It reduces the pressure difference needed to allow the lung to inflate. The lung's compliance decreases and ventilation decreases when lung tissue becomes diseased and fibrotic. As the alveoli increase in size, the surfactant becomes more spread out over the surface of the liquid. This increases surface tension effectively slowing the rate of expansion of the alveoli.
This also helps all alveoli in the lungs expand at the same rate, as one that expands more quickly will experience a large rise in surface tension slowing its rate of expansion. It also means the rate of shrinking is more regular, as if one reduces in size more quickly the surface tension will reduce more, so other alveoli can contract more easily than it can.
Surfactant reduces surface tension more readily when the alveoli are smaller because the surfactant is more concentrated. Surface tension draws fluid from capillaries to the alveolar spaces. Surfactant reduces fluid accumulation and keeps the airways dry by reducing surfacee tension.
These proteins can bind to sugars on the surface of pathogens and thereby opsonize them for uptake by phagocytes. It also regulates inflammatory responses and interacts with the adaptive immune response. Surfactant degradation or inactivation may contribute to enhanced susceptibility to lung inflammation and infection. Dipalmitoylphosphatidylcholine DPPC is a phospholipid with two carbon saturated chains and a phosphate group with quaternary amine group attached.
The DPPC is the strongest surfactant molecule in the pulmonary surfactant mixture. It also has higher compaction capacity than the other phospholipids, because the apolar tail is less bent.
Nevertheless, without the other substances of the pulmonary surfactant mixture, the DPPC's adsorption kinetics is very slow. This happens primarily because the phase transition temperature between gel to liquid crystal of pure DPPC is Neutral lipids and cholesterol are also present.
The components for these lipids diffuse from the blood into type II alveolar cells where they are assembled and packaged for secretion into secretory organelles called lamellar bodies.
The apolipoproteins are produced by the secretory pathway in type II cells. They undergo much post-translational modification, ending up in the lamellar bodies. The fast adsorption velocity is necessary to maintain the integrity of the gas exchange region of the lungs. Each SP protein has distinct functions, which act synergistically to keep an interface rich in DPPC during lung's expansion and contraction.
Changes in the surfactant mixture composition alter the pressure and temperature conditions for phase changes and the phospholipids' crystal shape as well. Nevertheless, it has been observed that if a lung region is abruptly expanded the floating crystals crack like " icebergs ". Even though the surface tension can be greatly reduced by pulmonary surfactant, this effect will depend on the surfactant's concentration on the interface.
The interface concentration has a saturation limit, which depends on temperature and mixture composition. Because during ventilation there is a variation of the lung surface area, the surfactant's interface concentration is not usually at the level of saturation.
The surface increases during inspiration, which consequently opens space for new surfactant molecules to be recruited to the interface. Meanwhile, at the expiration the surface area decreases, the layer of surfactant is squeezed, bringing the surfactant molecules closer to each other and further decreasing the surface tension.
SP molecules contribute to increase the surfactant interface adsorption kinetics, when the concentration is below the saturation level. They also make weak bonds with the surfactant molecules at the interface and hold them longer there when the interface is compressed.
Therefore, during ventilation, surface tension is usually lower than at equilibrium. Therefore, the surface tension varies according to the volume of air in the lungs, which protects them from atelectasis at low volumes and tissue damage at high volume levels. Surfactant production in humans begins in Type II cells during the alveolar sac stage of lung development.
Lamellar bodies appear in the cytoplasm at about 20 weeks gestation. Club cells also produce a component of lung surfactant. Alveolar surfactant has a half life of 5 to 10 hours once secreted. This process is believed to occur through SP-A stimulating receptor mediated, clathrin dependent endocytosis. In late s von Neergaard  identified the function of the pulmonary surfactant in increasing the compliance of the lungs by reducing surface tension.
However the significance of his discovery was not understood by the scientific and medical community at that time. He also realized the importance of having low surface tension in lungs of newborn infants.
Later, in the middle of the s, Pattle and Clements rediscovered the importance of surfactant and low surface tension in the lungs. At the end of that decade it was discovered that the lack of surfactant caused infant respiratory distress syndrome IRDS. From Wikipedia, the free encyclopedia. Main article: Pulmonary surfactant medication. April Retrieved May 10, Retrieved Respiratory physiology-- the essentials. Biology of the Neonate. Allen; Pillers, De-Ann M.
Molecular Genetics and Metabolism. Comparative Biochemistry and Physiology. Annual Review of Physiology. Journal of Applied Physiology. Pure and Applied Chemistry. Comparative Biochemistry and Physiology A.
Philadelphia, PA. Ch Respiratory physiology. Protein : cell membrane proteins other than Cell surface receptor , enzymes , and cytoskeleton. Pulmonary surfactant-associated protein B Pulmonary surfactant-associated protein C. Categories : Respiratory physiology Integral membrane proteins Surfactants Pulmonary function testing Lipopeptides.
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