APNEA FREQUENTLY PERSISTS BEYOND TERM GESTATION IN INFANTS DELIVERED AT 24 TO 28 WEEKS

Background. Apnea of prematurity remains among the most commonly diagn osed conditions in the Newborn Intensive Care Unit and may prolong hos pital stays in some infants. Because survival of extremely premature i nfants has improved markedly, the natural history of apnea in this pop ulation needs to be reassessed. Objective. To document the natural his tory of recurrent apnea and/or bradycardia events in infants delivered at 24 to 28 weeks' gestation. Methods. Medical records of all infants delivered at 24 to 28 weeks' gestation admitted to the Brigham and Wo men's Hospital Newborn Intensive Care Unit between January 1989 and Ma rch 1994 were reviewed to document the clinical course of apnea of pre maturity. Subjects were included in the study sample if they were disc harged home from the Brigham and Women's Hospital or after transfer to an affiliated hospital. Recordings of apnea and/or bradycardia events were based on nursing observations of monitor alarms and assessment o f the infant's condition. Results. Of 457 eligible infants, 226 were i ncluded in the study sample and stratified by gestational age at birth assigned by the attending neonatologist. The time to resolution of re current apnea/bradycardia events was longer with lower gestational age at birth. Apnea/bradycardia events were frequently observed beyond 36 weeks' postconceptional age in all gestational age groups. The incide nce of apnea persisting beyond 38 weeks postconceptional age was signi ficantly higher in the 24- to 27-week infants combined compared with t he 28-week infants. Conclusions. Apnea of prematurity frequently persi sts beyond term gestation in infants delivered at 24 to 28 weeks' gest ational age. These persistent apnea and/or bradycardia events may cont ribute to prolonged hospitalization. Programs to promote earlier disch arge of premature infants should take into account the variability in resolution of apnea and specifically address management of persistent apnea.