PREDICTION OF INDIVIDUAL-RESPONSE TO POSTNATAL DEXAMETHASONE IN VENTILATOR-DEPENDENT PRETERM INFANTS

Aims-To evaluate factors predictive of individual response to dexameth asone in preterm infants. Methods-A cohort of 74 preterm infants born between January 1993 and February 1996 was studied retrospectively. Al l of them had received dexamethasone to facilitate weaning from artifi cial ventilation. Demographic factors, ventilation parameters, and det ails of dexamethasone administration were recorded from the medical an d nursing notes. Radiographs were assessed by one observer who was una ware of the clinical condition of the infant or the outcome. Outcome v ariables examined included change in ventilation index (VI) at 36-48 h ours, the number of days to extubation from the start of dexamethasone , and death before extubation. Results-Most babies improved but change s in VI at 36-48 hours ranged from substantial deterioration to dramat ic improvement. No identifiable factors were significantly associated with this range of response. The median time to extubation was 6 days. The 36 babies who extubated within the first 6 days were: significant ly more mature; less likely to have pulmonary interstitial emphysema ( PIE) or pneumothorax; and had significantly lower VIs in the 12 hours preceding dexamethasone treatment. The postconceptional age at extubat ion was the same whether babies were extubated within or after the fir st 6 days. Multiple linear regression confirmed a significant associat ion between number of days to extubation and the three factors describ ed above (adjusted R-2=0.5126). Conclusions-Individual responses to de xamethasone can be partly predicted by gestation, the presence of PIE, and the VI before dexamethasone administration.