infant respiratory distress syndrome

infant respiratory distress syndrome (IRDS) or hyaline membrane disease (hī`əlĭn, –līn'), respiratory distress syndrome of newborns, most common in infants born prematurely or by cesarean section or having a diabetic mother. The immature lungs of such infants cannot retain air; the air spaces empty completely and collapse after the first (and each succeeding) exhalation. Plasma leaks out of the lung tissue and coats the air spaces with a pink coating that is glassy, or hyaline, in appearance, hence the alternate name of the disease. Exhaustion, resulting from the extreme effort required to breathe, has been responsible for the death of many afflicted infants.

IRDS is caused by a lack, in the immature lung, of a surfactant agent; the substance, a mixture of lipids and proteins, contributes to the elasticity of lung tissue and stabilizes air passages so that the lung remains partly aerated after each exhalation. Intensive care, including supplemental oxygen and, in the case of severe symptoms, aid in breathing from a ventilator, can often bring infants through the first five or six days, after which most recover completely. An artificial surfactant may be introduced into the lungs if a newborn is at high risk for IRDS. If labor begins prematurely and cannot be halted and tests show that the fetus's lungs are immature, steroids administered to the mother a few days prior to labor may promote lung maturation.

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infant respiratory distress syndrome [′in·fənt ′res·prə‚tȯr·ē di′stres ‚sin‚drōm]

(medicine)

A disorder usually affecting prematurely born infants and characterized by a rapid breathing rate, respiratory muscle retraction during expiration, and blood gas values reflecting oxygen deficiency, excessive carbon dioxide, and acidosis.