pediatrics
Respiratory Distress Syndrome in Neonates
Diagnosis of Respiratory Distress Syndrome in Neonates
Clinical evaluation Arterial blood gases (hypoxemia and hypercapnia) Chest x-ray Blood, cerebrospinal fluid, and tracheal aspirate cultures Diagnosis of RDS is by clinical presentation, including recognition of risk factors; arterial blood gases showing hypoxemia and hypercapnia; and chest x-ray. Chest x-ray shows diffuse atelectasis classically described as having a ground-glass appearance with visible air bronchograms and low lung expansion; appearance correlates loosely with clinical severity. Differential diagnosisincludes Neonatal Pneumonia and Transient Tachypnea of the Newborn None Persistent Pulmonary Hypertension of the Newborn None Aspiration Pulmonary Edema None Overview of Congenital Cardiovascular Anomalies None Neonates typically require cultures of blood. Cerebrospinal fluid cultures are not routinely done after birth because there is low incidence of meningitis associated with early-onset sepsis, but they may be done in certain cases (eg, blood cultures are positive for gram-negative bacilli, concern of late-onset sepsis) ( Diagnosis reference ). Clinically, group B streptococcal pneumonia is extremely difficult to differentiate from RDS; thus, antibiotics should be started pending culture results. RDS can be anticipated prenatally using tests of fetal lung maturity, which are done on amniotic fluid obtained by amniocentesis or collected from the vagina (if membranes have ruptured) and which can help determine the optimal timing of delivery. These are indicated for elective deliveries before 39 weeks when fetal heart tones,human chorionic gonadotropinlevels, and ultrasound measurements cannot confirm gestational age and for nonelective deliveries between 34 weeks and 36 weeks. Amniotic fluid tests include the Lecithin/sphingomyelin ratio Foam stability index test (the more surfactant in amniotic fluid, the greater the stability of the foam that forms when the fluid is combined withethanoland shaken) Surfactant/albuminratio Risk of RDS is low whenlecithin/sphingomyelin ratio is>2, phosphatidyl glycerol is present,foam stability index≥47, or surfactant/albuminratio is>55 mg/g. 1.Srinivasan L, Harris MC, Shah SS: Lumbar puncture in the neonate: Challenges in decision making and interpretation.Semin Perinatol36(6):445–453, 2012. doi: 10.1053/j.semperi.2012.06.007 