Static respiratory compliance in the newborn. I: A clinical and prognostic index for mechanically ventilated infants.

Accurate measures of the severity of respiratory disease are important, both clinically and epidemiologically. The apparent prognostic value of static respiratory system compliance (Crs) on the first day and mean appropriate fractional inspired oxygen (FIO2) in the first 12 hours of life were compared in 48 infants who received mechanical ventilation in a regional neonatal unit. Their median (range) gestation was 30 (25-41) weeks and they were representative of all 140 newborn infants born to residents of a geographically defined area who received mechanical ventilation over a 30 month period. Using the best cut off value (< or = 0.6 ml/cm H2O/m corrected for body length), static Crs predicted hospital death with 98% accuracy, 80% sensitivity, and 100% specificity. Using the best cut off value (> 0.60), mean FIO2 in the first 12 hours predicted hospital death with 81% accuracy, 80% sensitivity, and 81% specificity. Static Crs appeared to be a more accurate measure of respiratory function and disease severity than mean FIO2, perhaps because static Crs is less dependent on ventilator management than routine indices based on blood gases. Static Crs now merits wider evaluation, both as an aid to routine clinical management and as a prognostic index in comparative studies.