Does the experience with the use of nasal continuous positive airway pressure improve over time in extremely low birth weight infants?

Objective. Early use of nasal continuous positive airway pressure (ENCPAP) in extremely low birth weight (ELBW) infants continues to be a source of debate. Centers are applying this management strategy with varying success. Our center has implemented this strategy of care over the past 4 years, and the objective of this study was to evaluate the impact of experience over time with the use of ENCPAP on outcomes of ELBW infants. Methods. All ELBW infants who were born at our hospital since the institution of the ENCPAP practice (n=101) were analyzed retrospectively. Patients were divided into 3 terciles according to their birth date. A baseline group of ELBW infants who were born in the 2 years preceding the institution of the ENCPAP practice ( group 0; n=45) were used for comparison. Trends in practices and outcomes over time were analyzed using the 2-sided Cochran-Armitage linear trend test. Statistical significance for these trends were then analyzed again using a multivariate regression model controlling for significant variables. Bivariate analyses comparing individual groups were also conducted. Results. There were no significant trends in mortality rate among the baseline group and the 3 terciles since the institution of the ENCPAP practice (26.7% vs 26.5% vs 11.8% vs 18.2%). ENCPAP management increased in the surviving infants over time (14% vs 19.2% vs 65.52% vs 70.4%), whereas the use of surfactant decreased (51.5% vs 48% vs 13.3% vs 33.3%) and the incidence of bronchopulmonary dysplasia (BPD) decreased (33.3% vs 46.2% vs 25.9% vs 11.1%). The average ventilator days per infant decreased, the rate of sepsis decreased, and the average daily weight gain increased. There were no significant trends in the incidence of intraventricular hemorrhage or necrotizing enterocolitis (NEC). When comparing the cohorts of survivors in the 3 terciles since the institution of ENCPAP system, ELBW infants who were started on ENCPAP but intubated within 1 week (CPAP failure) decreased over time (38.5% vs 13.8% vs 7.4%). There were other trends that did not reach significance, such as increased incidence of necrotizing enterocolitis (NEC). In a multivariate analysis controlling for gestational age, birth weight, and sepsis, the incidence of BPD was significantly lower over time (regression coefficient = -1.002+/-0.375). Conclusions. The frequency of use of ENCPAP in ELBW infants and its success improved in our unit over time. The major positive association in this population was a reduction in BPD rates and an increase in average weight gain. Relation of ENCPAP and NEC should be evaluated further.