The effect of dexamethasone on respirator-dependent very-low-birth-weight infants is best predicted by chest X-ray

Background. Chronic lung disease (CLD) in premature infants shows a variabl e clinical course with different radiological manifestations. Objective. To evaluate the correlation between parameters of transmembrane permeability [albumin/secretory component (SC)] and osidative stress [malon dialdehyde (MDA)/SC] in tracheal aspirate fluid (TAF) and radiological find ings with the effect of a 5-day course of dexamethasone (0.5 mg/kg per day) . Materials and methods. Fifty ventilator-dependent premature infants with bi rth weights < 1,500 (gestational ages 23-31 weeks) and radiological signs o f early chronic lung disease (CLD) were treated with dexamethasone at day o f life 5-27 (median 10 days) because of respiratory deterioration. TAF was collected serially. Chest X-rays taken before and 8-10 days after dexametha sone were scored for changes of opacification, consolidation and hyperinfla tion/emphysema, and classified into three groups. Results. Twenty-four infants had a positive response to dexamethasone, defi ned as a reduction of the ventilation index FiO(2) x mean airway pressure > 40 % at day 51 compared to pretreatment values, About 80% of the responder s showed homogeneous lung spacification on chest X-ray. reflecting leaky lu ng syndrome. In contrast, seven of eight infants with predominantly emphyse ma on radiology were nonresponders; 80 % of infants with a mixed radiologic al picture characterized by predominance of consolidations alternating with regions of emphysema were also non-responders Ratios of albumin;SC and MDA /SC in TAF decreased significantly within 3 days after the onset of dexamet hasone. However, MDA/ SC was persistently higher in nonresponders compared to responders. Opaque lungs were largely improved by dexamethasone, in cont rast to streaky or patchy consolidations and emphysema. In a logistic regre ssion model, radiographic classification was the most important factor infl uencing the response to dexamethasone with a positive predictive value of 8 6%, followed by albumin/SC ratio. Conclusions. The optimum timing of dexamethasone treatment may be determine d by the stags of developing CLD and radiological findings rather than by t he age of the premature infant.