Surfactant administration for neonatal respiratory distress does not improve lung interstitial fluid clearance: Echographic and experimental evidence

Departments of Paediatrics and Emergency Medicine, San Antonio Abate Hospital, Tolmezzo, Italy.
Journal of Perinatal Medicine (Impact Factor: 1.36). 09/2010; 38(5):557-63. DOI: 10.1515/JPM.2010.096
Source: PubMed


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.

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    • "Using the same approach, they also studied the ultrasound appearance of surfactant deficiency in a group of 40 infants with a mean gestational age of 27 weeks compared to 15 significantly larger and more mature controls (mean gestational age: 30 weeks) [9]. In the very preterm population, respiratory distress syndrome is associated with a sonographic white lung image that remains unmodified after surfactant replacement [12]. "
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    ABSTRACT: Introduction At birth, lung fluid is rapidly cleared to allow gas exchange. As pulmonary sonography discriminates between liquid and air content, we have used it to monitor extrauterine fluid clearance and respiratory adaptation in term and late preterm neonates. Ultrasound data were also related to the need for respiratory support. Methods Consecutive infants at 60 to 120 minutes after birth underwent lung echography. Images were classified using a standardized protocol of adult emergency medicine with minor modifications. Neonates were assigned to type 1 (white lung image), type 2 (prevalence of comet-tail artifacts or B-lines) or type 3 profiles (prevalence of horizontal or A lines). Scans were repeated at 12, 24 and 36 hours. The primary endpoint was the number of infants admitted to the neonatal ICU (NICU) by attending staff who were unaware of the ultrasound. Mode of respiratory support was also recorded. Results A total of 154 infants were enrolled in the study. Fourteen neonates were assigned to the type 1, 46 to the type 2 and 94 to the type 3 profile. Within 36 hours there was a gradual shift from types 1 and 2 to type 3. All 14 type 1 and 4 type 2 neonates were admitted to the NICU. Sensitivity was 77.7%, specificity was 100%, positive predictive value was 100%, negative predictive value was 97%. Four type 1 infants were mechanically ventilated. Conclusions In the late preterm and term neonate, the lung ultrasound scan follows a reproducible pattern that parallels the respiratory status and can be used as a predictor of respiratory support.
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    ABSTRACT: The initiation of ventilation in preterm, surfactant-deficient sheep without positive end-expiratory pressure (PEEP) causes airway injury and lung inflammation. We hypothesized that PEEP and surfactant treatment would decrease the lung injury from initiation of ventilation with high tidal volumes. Fetal sheep at 128-day gestational age were randomized to ventilation with: 1) no PEEP, no surfactant; 2) 8-cmH(2)O PEEP, no surfactant; 3) no PEEP + surfactant; 4) 8-cmH(2)O PEEP + surfactant; or 5) control (2-cmH(2)O continuous positive airway pressure) (n = 6-7/group). After maternal anesthesia and hysterotomy, the head and chest were exteriorized, and the fetus was intubated. While maintaining placental circulation, the fetus was ventilated for 15 min with a tidal volume escalating to 15 ml/kg using heated, humidified, 100% nitrogen. The fetus then was returned to the uterus, and tissue was collected after 30 min for evaluation of early markers of lung injury. Lambs receiving both surfactant and PEEP had increased dynamic compliance, increased static lung volumes, and decreased total protein and heat shock proteins 70 and 60 in bronchoalveolar lavage fluid compared with other groups. Ventilation, independent of PEEP or surfactant, increased mRNA expression of acute phase response genes and proinflammatory cytokine mRNA in the lung tissue compared with controls. PEEP decreased mRNA for cytokines (2-fold) compared with groups receiving no PEEP. Surfactant administration further decreased some cytokine mRNAs and changed the distribution of early growth response protein-1 expression. The use of PEEP during initiation of ventilation at birth decreased early mediators of lung injury. Surfactant administration changed the distribution of injury and had a moderate additive protective effect.
    AJP Lung Cellular and Molecular Physiology 08/2011; 301(5):L712-20. DOI:10.1152/ajplung.00157.2011 · 4.08 Impact Factor
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