335 Surface Activity of Small Volume Airway Aspirates Suctioned During Neonatal Resuscitation

Abstract

Background: Only small amounts of surfactant are be needed for measuring biophysical activity in the captive bubble surfactometer (CBS). Using large sample volumes, amniotic fluid or gastric aspirates have been used before for prediction of lung maturity in neonates. With the CBS the analysis of surfactant samples from neonatal aspirates with small volumes and low amounts of phospholipids can be performed. Aims: To prepare surfactant samples from small volumes of oro-nasal aspirates suctioned during neonatal resuscitation, to determine the surface activity and to compare the results with clinical data. Methods: Suction aspirates and clinical data of 74 individuals were collected with parental consent, weighed and mucus, cell detritus plus large particles were removed. Subsequently the samples were ultracentrifugated. The pellet was resuspended at a ratio of 60µL/1g of original sample size. Then surface tension of 1-5µL of the samples was determined after 5 min adsorption to a ∽20µL bubble in the CBS using sucrose as a surfactant hypophase. Results: Surface tension of aspirates of neonates with a bw 2000g (35.8±9.9; p< 0.01). Absorption surface tension in non-ventilated neonates was significantly lower (34.1±9.8mN/m) compared to CPAP treated neonates (47.8±7.4 mN/m; p< 0.05) or mechanically ventilated individuals (48.4±5.6 mN/m; p< 0.01). Conclusions: Small volume airway samples from neonatal aspirates may be used to determine biophysical activity of the surfactant system quantitatively using the CBS. The obtained data correlate with the clinical course, birth weight and the mode of ventilatory support.