Newborn respiratory distress syndrome

In low doses, inhaled NO may have a beneficial therapeutic effect, since NO in the inspired air leads to pulmonary vasodilation. In persistent pulmonary hypertension of the newborn, NO inhalation has already been used with some success. NO inhalation as the treatment for acute respiratory distress syndrome, however, has been disappointing. Only transient improvements of oxygenation were detected and the outcome of placebo-controlled trials did not show any improvement... 

Lung surfactant is composed mainly of lipid with some proteins and carbohydrate and prevents the alveoli from collapsing. Surfactant activity is largely attributed to dipalmitoylphosphatidylcholine, which is synthesized shortly before parturition in full-term infants. Deficiency of lung surfactant in the lungs of many preterm newborns gives rise to respiratory distress syndrome. Administration of either natural or artificial surfactant has been of therapeutic benefit. 

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... 

Failure to synthesise sufficient surfactant or the synthesis of abnormal surfactant, so that surface tension cannot be lowered, may play a role in several conditions respiratory distress syndrome of the newborn sudden infant death ( cot death ) and adult respiratory distress syndrome. The enzymes involved in the synthesis of surfactant only appear during the third trimester of pregnancy, so that surfactant is not produced in premature babies and they have difficulty breathing. 

Inositol has been given in cases of diabetes for possible therapeutic effects on peripheral neuropathy at doses of 20 g/day with no side effects (Arendrup et al. 1989]. Recently, newborns were treated with inositol 80 mg/kg with marked benefit in respiratory distress syndrome, and no side effects were reported [Hallman et al. 1992]. In addition to the above, 10 psychiatrically healthy volunteers were given 12 g of inositol in a single dose, and no side effects or mood effects were reported [Levine et al. 1994] 15 patients were treated for 5 days each with 6 g of inositol daily for electroconvulsive therapy-induced confusion, with no clinical effects and no side effects (Levine et al. 1995b] and 4 patients with Li -induced electroencephalographic [LEG] abnormalities were treated for 7 days with 6 g daily of inositol [Barak et al. 1994] with minimal EEG effects and no side effects. 

Tolazoline is similar to phentolamine. Tolazoline has very limited clinical application in the treatment of pulmonary hypertension in newborn infants with respiratory distress syndrome. Its efficacy in this condition is doubtful, and the drug is rarely used. 

Lung surfactant decreases the surface tension and thereby maintains the morphology and function critical for respiration. Deficiency of surfactant in the newborn infant is a condition known as respiratory distress syndrome (RDS) and in adults as adult respiratory distress syndrome (ARDS). A number of commercial artificial surfactants, e.g. Exosurf and ALEC, together with natural surfactant preparations, e g. Surventa and Curosurf, are currently available to treat these conditions. 

Reproductive toxicity Effects that may alter the normal reproductive processes of an animal—for instance, loss of fertility Residue The pesticide remaining in a product after natural or other processes Respiratory distress syndrome A lung disease that occurs primarily in premature infants the newborn must struggle for each breath and blueing of its skin reflects the baby s inability to get enough oxygen can also affect adults Restricted-use pesticide (RUP) A pesticide that can be sold to or used by only certified applicators... 

Premature labour use of P -adrenoceptor agonists and of dexamethasone (to prevent respiratory distress syndrome in the prematurely newborn) causes hyperglycaemia and increased insulin (and potassium) need. 

In a double-blind, randomized pilot study of the efficacy and adverse effects of inhaled fluticasone in 25 newborn preterm infants who required mechanical ventilation for treatment of respiratory distress syndrome, the infants were randomized to receive inhaled fluticasone 1000 micrograms/day or placebo (47). The hypothalamic-pituitary-adrenal axis was assessed by the response to corticotropin-releasing factor. AU basal and post-stimulation plasma corticotropin and serum cortisol concentrations were significantly less with inhaled fluticasone than placebo. Cumulative high-dose inhaled glucocorticoids caused moderately severe suppression of both the pituitary and the adrenal glands. This systemic activity is probably associated with pulmonary vascular absorption that avoids hepatic first-pass metabolism. 

Gaseous nitric oxide is a short-lived molecule that has been used in the treatment of patients with primary pulmonary hypertension and is used in subgroups of severely ill and hypoxic children with persistent pulmonary hypertension of the newborn, in preterm infants of less than 34 weeks gestation, and in adults with acute lung injury and adult respiratory distress syndrome. There are some reports of its use for intestinal ischemia, reperfusion injury, thrombotic disorders, and sickle cell crises. 

Airway VIP content has also been measured in patients with the respiratory distress syndrome of the newborn. The VIP content of airways of children who died of acute respiratory distress syndrome did not differ from that of airways of age-matched control children who died of non-respiratory causes (Ghatei et al., 1983). 

Respiratory distress syndrome in premature newborns is caused by deficiency in the lungs of... 

Robert MF, Neff RK, HubbeU JP, Taeusch HW, Avery ME. Association between maternal diabetes and the respiratory-distress syndrome in the newborn. N Engl J Med 1976 294 357-60. 

With respect to safety and the use of phospholipids, no NDA-supporting chronic inhalation studies have been conducted except for those found in commercial pulmonary surfactants. These studies presumably will have involved intratracheal instillation and not aerosolization, since the primary indication is respiratory distress syndrome of the newborn. Nevertheless, the fact that these products are available suggests that synthetic versions of natural lipids such as dipalmitoyl phosphatidylcholine (DPPC) and dipalmitoyl phosphatidylglycerol (DPPG) are likely to be well tolerated. This assumption has been supported from subchronic aerosol studies in mice [60] and acute single-dose aerosol studies in man, the latter involving soy-derived phosphatidylcholines [61]. 

Verder H, Robertson B, Greisen G, et al. Surfactant therapy and nasal continuous positive airway pressure for newborns with respiratory distress syndrome. N Engl J Med 1994 331 1051-1055. 

Extracorporeal blood gas exchange devices have been used on infants with the respiratory distress syndrome (RDS) (4, 5). Twenty-five thousand newborns are estimated to die from this disease every year in this country (6). Though the causes of this disease are not clearly understood, it is hoped that supporting the infant with the aid of an extracorporeal-gas exchanger will give his own lungs time in which to heal. 

Premature infants, especially those with respiratory distress syndrome (RDS) who are incapable of full oral feeds, often receive TPN because of their extremely limited substrate reserve, very rapid growth rate, and perceived susceptibility to irreversible brain damage secondary to malnutrition. In addition, during the newborn period and first months of life, TPN is used in infants with intractable diarrhea and in those undergoing gastrointestinal surgery. The following section contains a brief review of these disease entities and of methods used to determine how and whether TPN affects their outcome. 

Phospholipids play an important role in lung functions. The surface active material to be found in the alveolar lining of the lung is a mixture of phospholipids, neutral lipids and proteins. Lowering of surface tension by the lung surfactant system and the surface elasticity of the surface layers assists alveolar expansion and contraction. Deficiency of lung surfactants in newborns leads to a respiratory distress syndrome and this led to the suggestion that instillation of phospholipid surfactants could cure the problem. 

A common problem for premature babies is their lack of pulmonary surfactant. The pulmonary surfactant is formed late in pregnancy, and a premature baby born without the surfactant can experience respiratory distress syndrome, whereby the alveoli can collapse, a potentially fatal condition. Treatment of newborn premature babies with a lung surfactant therapy was a major advance in neonatal medicine. 

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