HOME DOCUMENTED MONITORING OF CARDIORESPIRATORY PATTERN AND OXYGEN-SATURATION IN HEALTHY INFANTS

The objective of this study was to establish longitudinal normative li mits for home memory monitors during early infancy. Eighty-eight healt hy infants were monitored overnight at 0.25-19 wk of age using the Hea lthdyne Smart Monitor. Apnea settings were 14 s for recording and 40 s for alarm; the bradycardia setting was 50 beats/min (5-s delay) for b oth recording and alarm. Arterial oxygen saturation (Sao(2)) was docum ented whenever an event was recorded. The monitor was used 77% of all possible days; median daily use was 8.0 h. Eighty-three percent of all monitor alarms were caused by loose leads, the other 17% by false apn ea or false bradycardia. Of all recorded events, 68.9% were caused by false apnea or false bradycardia; the other 31.1% were central apneas that reached the recording threshold of 14 s. The longest apnea was 36 s (wk 1); the 95th percentile for longest apnea was 19.9 s in wk 1 an d 18.0 s in wk 17-19 (p < 0.001). Periodic low Sao(2) values occurred with tiles for lowest Sao(2) were 82 and 86% in wk 1 and 13-19, respec tively (p < 0.001), but the minimum value observed in any week was nev er > 81%. The median duration of Sao(2) < 90% was only 5 s but the ran ge was wide (1-183 s), and 39/527 episodes (7.4%) were > 10 s. In summ ary, these longitudinal data provide the first available normal limits for cardiorespiratory pattern and Sao(2) during documented home monit oring in early infancy. Utilization of these normative data will impro ve the diagnostic validity and clinical usefulness of event recordings .