[Transcutaneous oxygen tension and apnea during sleep stages in normal infants and infants at risk for sudden infant death syndrome]. / Pression transcutanée d'oxygène et apnées au cours des stades de sommeil chez des nourrissons normaux et à risque de MSIN.

The relationship between chronic hypoxemia and sudden infant death syndrome (SIDS) has been reported by several authors. In order to study the influence of the apnea-time during a sleep state on transcutaneous oxygen tension (tcPO2), we have studied polygraphically 30 full-term infants (10 controls, 10 SIDS siblings and 10 near-miss for SIDS), aged from 5 to 13 weeks. No significant difference was observed either for apnea-time or tcPO2 between infant-groups studied in different sleep states. We could not find any correlation between apnea-time and tcPO2 in all groups of infants studied during different states of sleep. It is therefore concluded that in normal and at risk for SIDS infants, tcPO2 levels during sleep states cannot be explained only by the apnea-time.

Effect of sleep position on transcutaneous oxygen tension in SIDS siblings.

To assess the influence of sleep position in sudden infant death syndrome siblings (SIDSS), we have studied 60 healthy SIDSS between the 1st and 3 + 4th month of life polygraphically. Infants were grouped according to postnatal age (1st, 2nd and 3 + 4th month) and sleep position (supine and prone). Transcutaneous oxygen tension (tcPO2) was continuously recorded and studied in each sleep state (active (AS) and quiet sleep (QS)) during the 1st and 2nd sleep cycle. No statistical difference could be found in tcPO2 levels as regards different sleep positions, postnatal ages (except for AS during the 2nd sleep cycle in prone and supine positions: 3 + 4th month greater than 2nd month, P less than 0.05), sleep states (except for the 1st month in supine: QS greater than AS, P less than 0.05; and 3 + 4th month in prone: AS greater than QS, P less than 0.05) or sleep cycles. tcPO2 variability was found to be significantly higher in AS as compared to QS (P less than 0.05). These results suggest that sleep position does not influence tcPO2 levels in SIDSS.

Respiratory pauses and periodic breathing assessed by cardio-pneumography in normal infants and in SIDS siblings.

450 cardio-pneumograms (CPG) were performed on two successive nights in 68 controls and 235 SIDS siblings. The number of respiratory pauses greater than or equal to 5 sec and greater than or equal to 10 sec (NP) and the time of periodic breathing (PB) were calculated per 100 minutes of recording. Recordings were arranged into five age groups corresponding to the 1st, 2nd, 3rd, 4th and 5th-6th month of life. No significant differences in NP and PB were found when controls and SIDS siblings were compared separately within each age group, neither as a function of gestational age (less than 40 weeks GA vs greater than or equal to 40 weeks GA), nor as a function of the results of the 1st vs the 2nd night of recording. Nor was any significant difference in NP and PB found when comparing control vs sibling babies within each age group for the 1st or for the 2nd night of recording. In SIDS siblings, there was a significant decrease in the three variables studied between the 1st and the 2nd month of life. No significant decrease was found in controls. We conclude that SIDS siblings are not different from controls of the same age when respiratory variables are studied by CPG recordings.

Are polygraphic and cardiopneumographic respiratory patterns useful tools for predicting the risk for sudden infant death syndrome? A 10-year study.

Between 1974 and 1984 we have studied 204 control infants (C) comparing them with 650 SIDS siblings (SS) and 146 near-miss for SIDS (NM). These 1,000 full-term infants were recorded by day polysomnography (DPSG; n = 417), night polysomnography (NPSG; n = 257) and cardiopneumography (CPG; n = 2,600). Records were visually analyzed. In DPSG and NPSG, total amount of central, mixed and obstructive apnea as well as the percentage of periodic breathing was studied in each sleep state (active sleep, AS; quiet sleep, QS; indeterminate sleep, IS, and total sleep, TS) and over the total recording time (TRT). In CPG, only the total amount of central apnea and percentage of periodic breathing over TRT were studied. Infants were grouped according to postnatal age: less than 5, greater than or equal to 5 to less than or equal to 13, and greater than 13 to less than or equal to 26 weeks. In each age group results were compared as follows: C vs. SS, C vs. NM, and SS vs. NM for each parameter studied. Before 5 weeks and after 13 weeks there was no significant difference between C and SS, C and NM, and SS and NM in DPSG and NPSG for all categories of central, mixed and obstructive apnea as well as the percentage of periodic breathing in different sleep states and over TRT. Similar results were obtained in CPG for all categories of central apnea and percentage of periodic breathing over TRT.(ABSTRACT TRUNCATED AT 250 WORDS)

Polysomnograms and cardiopneumograms in SIDS research.

Polysomnographic (PSG) and cardiopneumographic (CPG) recordings are commonly used in research on sudden infant death syndrome (SIDS). PSG and simultaneous CPG recordings were compared in order to clarify two practical problems: reliability of sleep state evaluation with CPG and comparability of the number of respiratory pauses evaluated by these two recording techniques. This comparison shows that: (1) evaluation of sleep states by CPG technique is only reliable for quiet sleep and (2) there was a significant difference in the number of pauses, the evaluation with PSG being systematically higher than with CPG. The abnormalities found or suspected in CPG home recordings must be confirmed by PSG in the laboratory.

Respiratory frequency during sleep in siblings of sudden infant death syndrome victims. A comparison with control, normal infants.

The present study was carried out on 76 polygraphic recordings performed on 38 siblings of sudden infant death syndrome victims and on 38 control (2 days to 18 weeks old) infants. Each sibling corresponded to a control infant according to gender, gestational age at birth and postnatal age criteria. We found that in siblings as in controls, respiratory frequency (RF) was higher in active sleep (AS) compared to quiet sleep (QS) state (P less than 0.05 for 11-18 week siblings, p less than 0.01 for the other groups). During the transitional sleep (TS), RF was on an intermediate level (AS greater than TS greater than QS). There were no significant differences between RF of siblings compared to controls, except that RF during QS in 6-10 week control infants was higher than in siblings of the same age (P less than 0.05). We found a wide variability between RF of different individuals within all the age groups of siblings and of controls (P less than 0.001). However, a high correlation was usually noted between RF found in different sleep states: some infants (siblings or controls) breathed more rapidly and others more slowly in all states studied. In siblings, as previously described in other groups of normal infants, RF seems to be an individual characteristic. In addition, the present work shows that according to RF criterion, healthy siblings are similar to normal infants.

Sleep apneas in normal neonates and infants during the first 3 months of life.

Sleep polygraphic recording was carried out on 52 normal full-term babies. 16 infants were recorded at 2 - 7 days of age, 14 at 2 to 5 weeks, 13 at 6 to 9 weeks and 9 at 10 - 13 weeks. Central apneas of 2 sec and over were analysed in Active Sleep (AS), Quiet Sleep (QS) and Transitional Sleep (TS). Apnea Index (AI, percent of non-breathing) and Number of Apneas (NA) per 100 min of sleep state (for 2 - 4 sec, greater than or equal to 5 sec, greater than or equal to 6 sec and greater than or equal to 10 sec apneas) were determined. Obstructive and mixed apneas were tabulated separately. % of Periodic Breathing (PB) was also determined. These results were statistically tested using different methods. AI and number of less than 5 sec apneas are higher in AS than in QS during the period studied. A decrease of AI and NA occurs before the end of the 2nd month both in AS and QS. During the first five weeks of postnatal life the AI, the NA and the % of PB are higher in infants born at 38 - 39 weeks of Gestational Age (GA) than in infants born at 40 - 42 weeks. A positive correlation between short apneas (less than 5 sec) and apneas greater than or equal to 5 sec was found in AS and in total sleep. Obstructive and mixed apneas were very infrequent. Apneas are not affected by recording technique, sex or sleeping position of infants. There is a great interindividual variability of NA, particularly during the first month of life. Little normative data has been published so far concerning the incidence of respiratory apneas during day sleep in full-term infants recorded by polygraphy.

Respiratory pauses in normal infants and in siblings of victims of the sudden infant death syndrome.

Sleep polygraphic recording was carried out on 57 normal infants and on 100 SIDS siblings during morning naps between birth and the 4th month of life. Total sleep time and duration of sleep stages were determined. Central apnoeas of 2 sec and longer duration were analysed in AS, QS and IS. Apnoea index and number of apnoeas per 100 min of sleep stage were determined. Obstructive and mixed apnoeas were tabulated separately. Percentage of periodic breathing was also determined. Control babies and SIDS siblings were compared on these parameters, using the Mann-Whitney test. Between the 6th and 13th weeks of life respiratory pauses were significantly more frequent in SIDS siblings than in control subjects. The difference disappeared after the 13th week. The roles that peripheral afferents and the circadian organization of respiratory pauses play in determining the results are discussed. This technique does not appear to permit estimation of the risk of subsequent apnoeic episodes.

[Waking-sleeping transition in the newborn baby and in infants before the age of 3 months (author's transl)]. / Transition veille-sommeil chez le nouveau-né et le nourrisson avant l'âge de 3 mois.

The mode of transition from waking to sleeping was studied using two methods: (1) by the simple observation of behavioural criteria (opening and closing of eyes, crying, motility), and in particular, rapid eye movements (REM); (2) from combined behavioural and polygraphic criteria (recorded REM, chin EMG, respiratory rhythm, EEG). This study shows that sleep may begin without complete eye closure, with half closed eyes or with brief, alternating opening and closing of the eyes. The modifications of the various polygraphic and behavioural parameters depend on the stage of sleep which is the outcome. The changes which most often condition the passage to a given stage of sleep are the following: (a) inhibition of the tonic chin EMG in the transition towards active sleep (AS); (b) modifications of the EEG in the transition towards quiet sleep (QS); (c) stopping of crying and of agitation in the transition towards indeterminate sleep (IS). The comparison of results obtained using the two methods of analysis shows that the simple observation of behavioural parameters overestimates the number of sleep inductions in AS. This method does not take into account discordances between polygraphic parameters. This study confirms the reduction with age of sleep onsets in AS, with a concomitant increase in sleep onsets in QS. It stresses the variability in the mode of onset of sleep in normal children of the same age group, as well as in successive sleep inductions in the same child.

Sleep and brain malformation in the neonatal period.

Polygraphic recordings of 20 neonates with brain malformations and/or chromosomal anomalies were compared with those obtained in 29 normal fullterm neonates. Seep assessment was made with different methods described in the literature. These methods of sleep scoring gave similar results in the normal newborn babies but discrepant results in many pathological neonates. Thus sleep was also studied by other approaches; assessment of cycling of the 5 parameters (EEG, REM, EMG, Motility, Respiration) and study of the discrepant parameters during a sustained period of Active sleep (AS) or Quiet Sleep (QS), defined by the most flexible method. Newborn babies with brain malformations appeared to be poor sleepers. Amount of wakefulness is higher than in normal neonates. Some babies were nearly insomniac. Correlations of sleep patterns and anatomical lesions were possible in five cases where brain anatomy was available. A good sleep organization has been seen in babies with normal brain-stems but a normal brain stem with a normal locus coeruleus has been found in a baby with absence of AS. Absence of sleep organization has been seen in babies with an abnormal brain stem; but this anomaly was not isolated as these babies also had lesions of the forebrain. The sleep of human neonates shows a greater liability in the coordination of the different parameters than the sleep of human adults or adult animals. It appears that sleep mechanisms at the pontine level present more plasticity than the rigid mono aminergic model would suggest.