Neuropediatrics 1982; 13: 15-20
DOI: 10.1055/s-2008-1059629
© Georg Thieme Verlag KG Stuttgart · New York

Phase Relationships Between Thoracic and Abdominal Respiratory Movement During Sleep in 31 - 38 Weeks CA Normal Infants. Comparison with Full-Term (39-41 Weeks) Newborns1

L.  Curzi-Dascalova
  • INSERM U 29, Hôpital Port-Royal, 123 boulevard de Port Royal, 75014 Paris, France
1 This work was partially supported by ATP 76-61 from INSERM Paris.
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Publication History

Publication Date:
19 March 2008 (online)

Abstract

This study was carried out in 30 premature and full-term newborns and in 6 prematurely borns, arriving at the age of normal term infants. Phase relationships between the upper thoracic and the abdominal respiratory movements were coded using independently 2 methods: according to the maximum phase shift observed during every 20 sec. epoch, and according to the minimum phase shift observed during the same 20 sec. epoch:
1. Both methods showed a predominance of the in-phase respirations in quiet sleep and the predominance of the 180° phase shift respiration in active sleep (p<0.001). The results were similar, without significant differences in all age groups.
2. The in phase thoracic and abdominal respiratory movements were accompanied by simultaneous inspiratory EMG activity at the upper intercostal (2nd or 3rd space) and the diaphragmatic levels. During the 180° out-of-phase respiration, the upper intercostal inspiratory EMG was selectively inhibited. During the approximately 90° out-of-phase respiration, it was usually present.

The present work shows that: 1) the thoraco-abdominal respiratory movement phase relationships are early ontogenetic criteria of sleep state organisation. 2) It confirms the hypothesis that the out-of-phase respiration is related to the selective inhibition of the upper intercostal muscles (rich in neuromuscular spindles) during active sleep.

The duality of sleep (Jouvet 1965) is confirmed by the differences between the respiratory patterns of slow-wave and REM sleep. From birth, the regularity and the frequency of the respiratory movements enable us to distinguish the active REM sleep (AS) from the quiet NREM (QS) sleep (references in Monod and Pajot 1965, Prechtl et al 1979, Dreyfus-Brisac et al 1981).

Phase relationships between thoracic and abdominal respiratory movements were recently described to be closely related to the sleep state in newborns and infants up to 10 months (references in Curzi-Dascalova 1978). In QS thoracic and abdominal respiratory movements occur usually in phase, while in AS, both movements occur out of phase: i.e. when the abdominal diameter increases the upper rib cage diameter decreases simultaneously. Phase shifts between thoracic and abdominal respiration were observed in premature infants by Frantz et al (1976), Vakhraméeva and Finkel (1976) and by Martin et al (1979). As in older infants, the in-phase respiration is found in QS, while the out of phase respiration is found rather in AS (Curzi-Dascalova and Korn 1980). On the contrary, for Davi et al (1979), chest distortion, related to the out-of-phase respiration "was not affected by sleep state, but was more frequent in preterm than in term infants". In fact, some previous publications do not describe the methodology of coding of respiratory phase relationships, which could explain the differences in the results. Nor do we know of any follow-up of thoracico-abdominal phase relationships on continuous, long duration sleep recordings, for groups of infants at different ages, from premature to normal term.

The aim of the present work is to study:
1. The correlations between the sleep states on one hand and the thoracico-abdominal phase relationships on the other, in groups of normal infants from 31 weeks to 41 weeks conceptional age (CA).
2. This study is performed independently using two methods: first, thoracico-abdominal phase relationships are coded according to the maximum phase shift observed in a given 20 seconds epoch; second coding is made according to the minimum thoracico-abdominal phase shift observed in the same 20 sec. epoch.
3. Different respiratory phase relationships are correlated with the electromyographic (EMG) activity observed at the diaphragmatic and at the intercostal muscle levels.

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