Surfactant administration for neonatal respiratory distress does not improve lung interstitial fluid clearance: echographic and experimental evidence.
ABSTRACT Recent ultrasonographic studies suggest that the administration of surfactant to preterm infants with respiratory distress syndrome (RDS) does not affect lung water clearance. The purpose of the study was also to look at clearance of lung water in preterm rabbits receiving surfactant.
Lung ultrasound was performed in 73 neonates at different gestational ages (range 23-34 weeks) with radiological and clinical signs of RDS, before and after surfactant administration. In premature rabbits (28-29 days' gestational age), either receiving or not receiving surfactant, we followed the time course of lung water balance considering the wet weight/dry weight ratio, the morphology and compliance of alveoli and pulmonary interstitial pressure.
In all RDS infants lung ultrasound images consistently showed a generalized increase in extravascular lung fluid which remained unchanged after surfactant administration and did not affect the rate of fluid clearance. Surfactant administration in premature rabbits did not improve the time course of lung fluid clearance.
Data from ultrasound in preterm babies are confirmed by animal experiments.
SourceAvailable from: Francesco Raimondi[Show abstract] [Hide abstract]
ABSTRACT: Chest ultrasound is a useful diagnostic tool in adult emergency medicine. Echography does not generate a clear image of the lung but is able to generate artifacts that are combined in disease-specific profiles. Reflections of the pleural image appear as short straight lines also known as A-lines. Vertical, comet-tail artifacts departing from the pleura are named B-lines. The former are present in the normal lung while the latter have been described in the adult wet lung. Lung ultrasonography outperforms conventional radiology in the emergency diagnosis of pneumothorax and pleural effusions. Neonatologists and pediatricians are now adapting lung ultrasound to their specific clinical issues. The normal image is relatively unchanged throughout the age span, while progressively fading B-lines describe the fluid-to-air transition of the neonatal lung. Also, an homogeneous white (hyperechogenic) lung with pleural image abnormalities and absence of spared areas is accurate in diagnosing Respiratory Distress Syndrome (RDS). The prevalence of A-lines in the upper lung fields with B-lines at the bottom fields (aka double lung point artifact) is highly sensitive and specific in describing Transient Tachypnea of the Newborn. Infantile pneumonia has recently been proved an accurate diagnosis by ultrasound after a short training. In summary, chest ultrasonography has no ground to replace conventional chest radiology tout court. However, when appropriately applied, a lung ultrasound scan can save time and radiation exposure to achieve a critical diagnosis.
[Show abstract] [Hide abstract]
ABSTRACT: Lung ultrasound is useful for the diagnosis of pneumonia in children and adults. This study investigated the lung ultrasound findings in severe neonatal pneumonia. From September 2012 to October 2013, 80 neonates admitted to Bayi Children's Hospital, affiliated with the Beijing Military General Hospital, were divided into two groups: a study group of 40 neonates who were diagnosed with severe pneumonia according to their medical history, clinical manifestations, and chest X-ray findings; and a control group of 40 neonates with no lung disease. All subjects underwent bedside lung ultrasound examination in a quiet state, performed by a single expert physician. Ultrasound findings including pleural line abnormalities, B lines, lung consolidation, air bronchograms, bilateral white lung, interstitial syndrome, lung sliding, and lung pulse were compared between the two groups. The lung ultrasound findings associated with infectious pneumonia of the newborn included large area of lung consolidation with irregular margins and air bronchograms, pleural line abnormalities, and interstitial syndrome. A large area of lung consolidation with irregular margins had 100% sensitivity and 100% specificity for diagnosing neonatal pneumonia. Lung ultrasound is a reliable tool for diagnosing neonatal pneumonia. It is suitable for routine use in the neonatal intensive care unit, and may eventually be able to replace chest X-ray and CT.Chest 05/2014; 146(2). DOI:10.1378/chest.13-2852 · 7.13 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: To investigate the nature of alveolar mechanical interdependence, we purposefully disturbed the equilibrium condition by administering exogenous surfactant in physiological non-surfactant deprived conditions. Changes in alveolar morphology induced by intra-tracheal delivery of CUROSURF were evaluated after opening a pleural window allowing in-vivo microscopic imaging of sub-pleural alveoli in 6 male anesthetized, tracheotomized and mechanically ventilated rabbits. Surfactant instillation increased the surface area of alveoli smaller than 20,000μm(2) up to ∼50% at 15min after instillation, reflecting a lowering of surface tension due to local surfactant enrichment. Conversely, for alveoli greater than 20,000μm(2), surface area decreased by ∼5%. Opposite changes in alveolar surface are interpreted as reflecting a new inter-alveolar mechanical equilibrium modified by local surfactant distribution and by a decrease in lung distending pressure. We propose that smaller alveoli, representing the majority of alveolar population, might mostly contribute to improve the oxygenation index following surfactant replacement therapy in case of surfactant deficiency. Copyright © 2015. Published by Elsevier B.V.Respiratory Physiology & Neurobiology 01/2015; 210. DOI:10.1016/j.resp.2015.01.009 · 1.97 Impact Factor