A Study of Relation between Stable Microbubble Rating and Pulmonary Surfactant Concentration in vitro

ABSTRACT

Respiratory distress syndrome (RDS) of preterm infants remains a significant cause of morbidity and mortality despite improvements in neonatal intensive care and artificial ventilatory techniques. After identification of the deficiency of pulmonary surfactant is major pathophysiologic basis in RDS, artificial surfactant replacement therapy in RDS was first successfully tested by Fujiwara and co-workers in 1980. therefore, exogenous surfactant replacement produced exellent results in improved clinical and repiratory status during the acute period and decreased incidence of late complications and mortality. According to comparison of administration timing between early (within 6 hours after birth) and late (after 6 hours)group, early replacement therapy is more effective in improving of clinical course and prognosis. Because of that, early, just after birth, recognition and detection of RDS is also important procedure. There are many investigations and methods for the detection of RDS in prenatal or postnatal period. Among then, stable microbubble rating (SMR) test was a simple method and SMR test has a higher diagnostic accuracy. To determine the relation of the SMR and purified natural surfactant (PNS) concentration in vitro, the author conducted each 5 times test of SMR method according to 5 groups of PNS concentration by using modified Pattle's method. The results were as follows 1) The mean and standard deviation of SMR according to 5 groups of PNS concentration were 119.4 (15.0in 20mug PL (phospholipid)/ml, 452.2 (160.2 in 40mug PL/ml, 879.0 (93.4 in 60mug PL/ml, 1311.8 (274.8in80mug PL/ml, 1710.6(272.3 in 100mug PL/ml. 2) The regression curve of SMR and PNS concentration showed statistically significant relation(p<0.005). In conclusion, the SMR test was a good method in estimation of surfactant concentration in vitro and also in diagnosis of RDS recognized as a surfactant deficiency. In the future, we expected that prophylactic surfactant replacement therapy. immediate after birth, will be more popular in the field of neonatal care of RDS. So, we recommended the use of this method for early detection and serving optimal care of RDS.