Post Discharge Cardiorespiratory Events in Preterm Infants

Background: home monitors designed to identify cardiorespiratory events are frequently used for premature infants who suffer from persistent apneic and/ or bradycardic events after they are otherwise ready for discharge home. objective: we have hypothesized that using event recording monitor will characterize the events during home monitoring and identifies at what postconceptional age (pca) the infants are event free.materials and methods: 12 hours bedside four channel pneumogram was performed on 452 preterm infants born at <34 weeks of gestational age before hospital discharge. 108 infants had at least one episode of apnea>20 second and/ or one episode of bradycardia< 80 beats per minute (bpm) for >5 second and they were considered symptomatic and discharged on event recording monitor. the monitor documented transthoracic impedance, electrocardiogram and heart rate. the monitor was downloaded at least once a month. an event was considered to be significant when an apnea lasted >20 seconds or when the heart rate was <80 bpm for >5 seconds for pca <44 weeks and <60 bpm for pca >44 weeks. each infant was monitored for at least one month after the last event infants who were monitored for <50% of available days or <8 hours per day were excluded from the study.results: duration of post discharge monitoring ranged from 4-30 weeks (median 7 weeks). when the patients were events free pca ranged from 34-55 weeks (median 39 weeks). compliance for the usage of monitor for available days was 50- 100% (median 100%). for daily use the time range was 8-12 hours (median 19 hours). during 152,664 hours of home monitoring 1,240 events were recorded. of these events only 184 were apnea more than 20 seconds 47% of infants did not have apnea >20 seconds after discharge. 80% of infants with apneic episode had <5 episodes during home monitoring. bradycardia without apnea of at least 20 seconds represented 32% of the events. 75% of bradycardiac episode were associated with short apnea (10±4 seconds).conclusions: preterm infants discharged home on event recording monitor had low incidence of apnea >20 seconds. using event record monitor will characterize the events during home monitoring and is helpful in determining the appropriate time of discontinue monitoring.