Respiratory distress syndrome, neonates

Infant respiratory distress syndrome (IRDS), also known as hyaline membrane disease, is one of the most common causes of respiratory disease in premature infants. In fact, it occurs in 30,000 to 50,000 newborns per year in the U.S. — most commonly in neonates bom before week 25 of gestation. IRDS is characterized by areas of atelectasis, hemorrhagic edema, and the formation of hyaline membranes within the alveoli. IRDS is caused by a deficiency of pulmonary surfactant. Alveolar type II cells, which produce surfactant, do not begin to mature until weeks 25 to 28 of... 

T Kobayashi, K Tashiro, X Cui, T Konzaki, Y Xu, C Kabata, K Yamamoto. Experimental models of acute respiratory distress syndrome clinical relevance and response to surfactant therapy. Biology Neonate 80 Suppl 1 26—28, 2001. 

Conversely, the role of perfluorocarbons for oxygen transport and in vivo delivery is investigated. In addition to possible use as temporary blood substitute, these fluorocarbon molecules can be applied as respiratory gas carriers, for instance as lung surfactant replacement compositions for neonates and possibly for the treatment of acute respiratory distress syndrome for adults. Another... 

In an analysis of 595 preterm infants born at 26-32 weeks gestation during a randomized controlled trial for the prevention of lung disease, glucocorticoids given to women at risk of preterm delivery promoted fetal lung maturation, reduced the incidence of respiratory distress syndrome, and reduced neonatal morbidity and mortality (370). Dexamethasone was given as either two doses of 12 mg 24 hours apart or four doses of 6 mg every 6 hours. Mortality was 9.2% after three or more courses, compared with 4.8% after one or two courses. This association was not explained by other factors (maternal or other common preterm morbidities). 

In 534 individuals aged 30 years, whose mothers had participated in a double-blind, randomized, placebo-controlled trial of antenatal betamethasone (two intramuscular doses 24 hours apart) for the prevention of neonatal respiratory distress syndrome, there were no differences between those exposed to betamethasone and placebo in body size, blood lipids, blood pressure, plasma cortisol, prevalence of diabetes, or history of cardiovascular disease (397). After the oral glucose tolerance test, those who had been exposed to betamethasone had higher plasma insulin concentrations at 30 minutes (61 versus 52 mIU/1) and lower glucose concentrations at 120 minutes (4.8 versus 5.1 mmol/1) than did those exposed to placebo. Antenatal exposure to betamethasone might result in insulin resistance in adult offspring, but has no effect on cardiovascular risk factors at 30 years of age. 

In 192 adult offspring (mean age 31 years) of mothers who had taken part in a randomized controlled trial of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome (87 exposed to betamethasone two doses 24 hours apart, and 105 exposed to placebo) there were no alterations in cognitive functioning, working memory and attention, psychiatric morbidity, handedness, or health-related quality-of-life in adulthood (400). 

There are also several examples of natural surfactants and foams in the human body. The understanding of the pulmonary surfactant system, although discovered in 1929, has only been applied clinically since about 1990 for the treatment of respiratory distress syndrome. Surfactant replacement therapy may also be used in treating other forms of lung disease, such as meconium aspiration syndrome, neonatal pneumonia and congenital diaphragmatic hernia [881]. Lung surfactant, composed of phospholipids and proteins [882,883], is necessary to maintain a low surface tension at the alveolar air-liquid interface. When there is a deficiency of surfac-... 

Two neonates had transient (0.5-2 minutes) chest wall rigidity after intravenous boluses of fentanyl 2 and 4 pg/kg. They were already compromised, one with a respiratory distress syndrome and one with a diaphragmatic hernia. 

In premature neonates and children with respiratory distress syndrome treated with a perfluorocarbon, pneumothorax has been observed (2). 

Therapeutically, lecithin and derivatives have been used as a pulmonary surfactant in the treatment of neonatal respiratory distress syndrome. 

Once one knows the problem and has devised a solution, then the real job begins. National Center for Health Statistics data show a decline in total US infant mortality from 1982 to 1992, but marked geographic and racial differences remain. The 1992 overall US rate of infant death was 8.5 per 1000 live births (California, 6.9 Texas, 7.7 New York, 8.5 New Jersey, 8.5 Pennsylvania, 8.6 Ohio, 8.7 Florida, 9.1 Illinois, 10.0 Georgia, 10.4 Michigan, 10.5) - a decline attributed not to reductions in the numbers of birth defects or premature births but to improved neonatal intensive care units and the introduction of synthetic pulmonary surfactants and consequent reductions in death from acute neonatal respiratory distress syndrome. Still, the years of potential life lost due to birth defects ranks fifth, just behind that of homicide and suicide (1, unintentional injury 2, cancer 3, cardiovascular disease) prematurity/low birth weight ranks sixth and sudden infant death syndrome seventh. Ethnic discrepancy remains pronounced rates of White (5.8 per 1000 live births) and Cuban Hispanic (3.7 per 1000 live births) infant death are similar, but the 2002 rate for Blacks (13.9 per 1000 live births) increased compared to the previous year. 

Increased Utilization. Secondarily low levels of AAT are seen in the neonatal respiratory distress syndrome, severe neonatal hepatitis, and severe preterminal disease of the pancreas. In nonfatal pancreatitis, levels increase along with those of other APR, and increased levels of complexes with trypsin are probably a better marker for use in either differential diagnosis or prognosis in patients with possible pancreatitis. 

Wijnberger LD, Huisjes AJ, Voorbij HA, Franx A, Bruinse HW, Mol BW. The accuracy of lamellar body count and lecithin/sphingomyelin ratio in the prediction of neonatal respiratory distress syndrome a meta-analysis. BJOG 2001 108 583-8. 

The delivery of aerosol powders by generation with minimal formulation has been an attractive prospect to many researchers. The early use of a dry powder artificial phospholipid in the treatment of neonatal respiratory distress syndrome proved very successful [181]. Because no delivery system was available to facilitate this treatment, a simple system was devised. A Laerdal neonatal resuscitation bag was modified to hold a capsule containing the artificial surfactant, as shown schematically in Fig. 11. However, where MDIs of the prescribed medication are available, both physicians and patients prefer their use. The powders themselves have to be prepared in the same way as those used in MDIs, by milling. Often, excipients are added to carry the fine powder. Lactose has been used in both cromolyn sodium and albuterol formulations. As a consequence of the interest in dry powders, a number of products have been... 

Instillation of surfactant improves outcome in premature infants with neonatal respiratory distress. Loss of surfactant is probably a contributing factor in pathogenesis of acute respiratory distress syndrome in adults, so there has been an... 

Neonatal respiratory distress syndrome (RDS) is predominantly a disease of surfactant deficiency. 

This chapter addresses the problems of acute respiratory distress syndromes in neonates, children, and adults. Abbreviations are used throughout the text, and a glossary for physiology, diseases, and drugs is presented in Table 28-1. Descriptions of ventilator-related terms are provided in Tables 28-2 and 28-3. Because the physiology of neonatal respiratory distress syndrome (RDS) and acute respiratory distress syndrome (ARDS) has some differences, these diseases will be discussed separately. 

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