Objektives: Periodic variations of oxygen saturation are often found i
n infants during periodic breathing. Aim of this study was to examine
this phenomenon more systematically. Methods: ECG, respiration and art
erial oxygen saturation (pulse oximetry) were recorded on 104 preterm
and 100 term infants (mean sleep recording time 14.2 hours). In 15 inf
ants showing marked variations of oxygen saturation additional simulta
neous oxyten saturation measurements at the right hand and foot were p
erformed. Results: 98 % of preterm and 57 % of term infants showed per
iodic oxygen saturation variations during periodic breathing. The peak
to peak amplitude of oxygen saturation was between 2 and 35 % with fa
ll and rise times of 3.0-8.1 secends. The simultaneous measurements sh
owed significantly higher variations at the foot. Conclusions: Periodi
c breathing is accompanied by periodic variations of oxygen saturation
in a high percentage. Some infants showed acute hypoxaemia during the
se episodes. According to our results of simultaneous oxygen saturatio
n measurements a periodically occurring, intermittent right to left sh
unting via the foetal circulation pathways is discussed as an explanat
ion.