Lung ultrasound in respiratory distress syndrome: a useful tool for early diagnosis.

BACKGROUND: Respiratory distress syndrome (RDS) is a severe form of neonatal respiratory distress which occurs almost exclusively in premature infants. At present, the diagnosis is based on radiological findings and clinical course. Lung ultrasound in RDS has not yet been fully assessed. OBJECTIVES: The aim of the study was to define the ultrasonographic appearance of RDS and evaluate its clinical relevance. METHODS: Lung sonography was performed in 40 newborn infants with radiological and clinical signs of RDS (mean gestational age 27.2 +/- 2.7 weeks, mean birth weight 1,057 +/- 361 g) and in 15 preterm infants without RDS (mean gestational age 30.4 +/- 3.4 weeks, mean birth weight 1,775 +/- 669 g). RESULTS: In all the studied infants with RDS, lung ultrasound consistently showed generalized alveolar-interstitial syndrome (echographic 'white lung'), pleural line abnormalities (small subpleural consolidations, thickening, irregularity and coarse appearance) and an absence of areas with a normal pattern ('spared areas'). When presented simultaneously, these signs identify RDS with a sensitivity and specificity of 100%. CONCLUSIONS: We found that lung ultrasound is a reliable tool in the diagnosis of RDS. We speculate that it may be considered as a screening method for the diagnosis of RDS, and for early administration of surfactant in preterm infants with respiratory distress.

Correlation between plasma and urinary caffeine levels in preterm infants.

BACKGROUND: We hypothesize that urine levels might be reliable to assess the therapeutic range of caffeine. OBJECTIVES: We correlated plasma and urinary levels of caffeine in preterm infants treated with this drug for apnea of prematurity. METHODS: Infants (n=56) were given a loading dose of caffeine citrate (10 mg/kg, per os) and 24 h later a maintenance dose (2 mg/kg, per os, once a day). Plasma and urinary levels of caffeine were determined 24 h after the loading dose (before administration of the maintenance dose) and then weekly. RESULTS: Plasma and urinary levels correlate at all examined ages: 29 weeks (r=0.92, P<0.001), 30 weeks (r=0.97, P<0.001), 31 weeks (r=0.82, P<0.001), 32 weeks (r=0.92, P<0.001), 33 weeks (r=0.87, P<0.001), 34 weeks (r=0.81, P<0.001). CONCLUSION: Urinary levels of caffeine might be a useful means to assess therapeutic ranges.