EMBRYONIC DEVELOPMENT OF THE RESPIRATORY SYSTEM

Embryonic Development Of The Respiratory System



Embryonic Development Of The Respiratory System

Infant respiratory distress syndrome ("RDS", also called "Respiratory distress syndrome of newborn", previously called hyaline membrane disease), is a syndromecaused by developmental lack of surfactantand structural immaturity in the lungsof prematureinfants. RDS affects about 1% of newborn infants. The incidence decreases with advancing gestational age (length of pregnancy), from about 50% in babies born at 26-28 weeks, to about 25% at 30-31 weeks. The syndrome is more frequent in infants of diabetic mothers and in the second born of premature twins. (Blackburn 2007:15-20)

For those born prematurely, comparisons between SGA and appropriate-for-gestational age (AGA) infants have generally shown that SGA infants have fewer respiratory difficulties in the neonatal period than AGA infants. However, these conclusions were drawn when the birth weight rather than the gestational age served as the basis for comparison. The limited number of studies comparing premature AGA and SGA infants of similar gestational age have shown inconclusive outcomes. Furthermore, there is a paucity of information regarding the outcome of infants born at extremely low gestational age (ELGA). (Dudek 2004:32-85)

The present study addresses the issue of outcome of SGA infants born between 24 and 26 6/7 weeks of gestation, an age group which was very difficult to study earlier. Nowadays, with the routine use of ultrasound between 16 and 20 weeks of gestation in the province of Quebec, it is possible to accurately date a pregnancy (Lott 1998:16-20). Furthermore, the survival rate of infants of extremely low birth weight (ELBW) and ELGA has increased in the last decade. This permits the evaluation of the impact of early intrauterine growth retardation on the outcome of infants born before 27 weeks of gestation. (Blackburn 2007:15-20)

Respiratory distress begins shortly after birth, and is manifest by a whining noise, flaring of the nostrils and "sucking in" of the chest wall during breathing efforts. The baby may become cyanotic ("blue") from lack of oxygen in the blood(Whitaker 2001:55-85). As the disease progresses, the baby may have respiratory failure, and prolonged cessations of breathing ("apnea"). If untreated, the baby's condition may worsen, and deathmay ensue. Complications include metabolic exhaustion (acidosis, low blood sugar), patent ductus arteriosus, low blood pressure, chronic lung changes, and intracranial hemorrhage. (Blackburn 2007:15-20)

In supplement to being on a ventilator and/or obtaining oxygen, it is expected that your premature baby will furthermore be on antibiotics, because ...