STATIC RESPIRATORY COMPLIANCE IN THE NEWBORN .2. ITS POTENTIAL FOR IMPROVING THE SELECTION OF INFANTS FOR EARLY SURFACTANT TREATMENT

Static respiratory system compliance (Crs) and lecithin/sphingomyelin (L/S) in tracheal aspirates were estimated in two independent groups o f mechanically ventilated infants. Crs was measured rapidly at the cot side using a passive expiratory flow technique and L/S ratios were est imated in the laboratory by high performance liquid chromatography. In the reference group of 22 infants, Crs <1.8 ml/cm H2O/m predicted sur factant deficiency with a positive predictive value of 100% and a nega tive predictive value of 92%. In the validation group of 23 infants, C rs <1.8 ml/cm H2O/m predicted surfactant deficiency with a positive pr edictive value of 94% and a negative predictive value of 83%. Measurem ent of static Crs is a rapid, non-invasive technique which may usefull y supplement current methods of selecting infants at high risk of resp iratory distress syndrome.