Oxygenation and Breathing Pattern in Healthy Term Infants During Sleep

Abstract □ 164

Background: Infants with pulmonary problems and those who are considered to be at risk for life threatening are usually monitored during sleep for episodes of hypoxemia or abnormal respiratory events. However the definitions of "abnormal" respiratory patterns vary since there are few studies on normal healthy infants specifically recruited for his purpose.

Study design and methods: Cross section study of 44 healthy term infants recruited prospectively as age and sex matched controls for babies with life threatening events (ALTE). The infants were examined at 7.2 (2 -36) wk. postconceptional age. Their mean GA was 39±0.9 wk., mean BW 3520±520g and mean weight at study 5699±1663g. Overnight polysomnography (330± 45 min) was performed in all infants. SaO₂, transcutaneous pO₂ and pCO₂ heart rate and rib cage and abdominal breathing movements were recorded continuously. Data were stratified for sleep states (active sleep-AS, quiet sleep-QS) and analysed with respect to age related changes. All recordings were manually reviewed for recording artefacts.

Results: (Table) Five infants (11,3 %) had episodes of SaO₂ <90% (mean of 86,2±1,5 %). Four of those occurred in conjunction with partial upper airway obstructions during AS. Periodic breathing (PB) defined as more than three consecutive respiratory pauses > 3sec was observed in 38,6 % of infants.

Table 1

Conclusion: Oxygenation and CO2 levels in sleeping healthy infants are comparable to adults. Hypoxic episodes are very infrequent and most often associated with partial upper airway obstruction. PB, which is often considered to be a pathological feature, is a normal breathing pattern in this age group.

Supported by MFR grant (k98-27x-11265-04a)