Neonatal respiratory distress syndrome Diagnosis

Neonatal respiratory distress syndrome is diagnosed by laboratory tests and imaging examination: 1) Imaging: X-ray irradiation; 2) laboratory tests: includes prenatal amniotic fluid and post partum endotracheal substance test. Diagnosis for NRDS include many tests which are higher sensitivity and specificity.

1. Biochemical examination:
The general use of thin layer chromatography (TLC), in late pregnancy (3rd trimaster) the beginning of the PC and S is about equal to 34 weeks gestational age when the rapid increase in PC, and S is relatively stable or slightly reduced, so L / S ratio increased. Shortly thereafter (at about 35 weeks gestational age) began to appear PG, that is, a rapid increase in the event. Thus 34 ~ 36 weeks gestational age is the best stage of the experiment to test.

1) L / S ratio: L / S ≥ that "lung maturation", 1.5 ~ 2 that the transition value or suspicious, "said 1.5" immature lungs. " Meconium contaminated amniotic fluid, such as not serious or the Department of outflow from the vagina, have little effect on the detection value. Diabetic pregnant women L / S value often high, although in some cases> 2, but can still occur infant RDS, maternal diabetes and therefore can not rely on a check and other tests required (such as PG) cross-referencing, more reliable.

2) PG: PG in PS to achieve 3% to the expression of thin-layer chromatography, as long as the existence of PG that "the lung is ripe", and its high sensitivity, but low specificity (about 75%) .

3) DPPC value: measured value> 500mg/dl that lung maturity, but about 10% of subjects although the DPPC has reached 500 ~ 1000mg/dl, still a NRDS.

2. Foam test:
Principle is that PS will help the formation and stability of foam, and pure alcohol is to prevent the formation of a bubble. Methods: Amniotic fluid or bronchial secretions 0.5 ~ 1.0ml, equivalent 95% increase in alcohol, forced sway 15 seconds, 15 minutes after the vigil to observe in vitro the formation of liquid around the bubble, no bubble for (-), ≤ 1 / 3-week test-tube a small bubble for the (+),> 1 / 3 weeks to the entire test tube test-tube one week in vitro (++), small bubble foam layer upper (+++), (-) indicated that less PS, can be diagnosed for the lack of symptoms, (+) or (+ +) as suspicious, (+++) said more than PS. The method for the bubble law a law, can also be done using four test-tube bubble method, refer to Chapter III of Section III of the physiology and functions of amniotic fluid.

3. X-ray tests:
On both sides of early hyaline membrane, can see reduce the brightness of lung permeability with a uniform distribution of small particles. Small particles represented small alveolar atelectasis, reticular shadow of the small blood vessels on behalf of congestive bronchus, and shows bronchi fill with air, but easily be covered by shadow of the heart and thymus. If atelectasis extended into the entire lung, the lung showed ground-glass, so that the inflatable bronchial show more clearly. Chest X-ray can help to diagnosis for respiratory distress syndrome.