No abstract

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.

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: < 5, ≥ 5 to ≤ 13, and > 13 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. Between 5 and 13 weeks, results were comparable with those given above, except for central apnea between 2 and 5 s in DPSG, being more numerous in both NM and SS compared with C in AS (p < 0.001 and < 0.01, respectively), and in TS (p < 0.01 and < 0.001, respectively). 146 NM infants were compared according to whether they subsequently had no NM event (n = 117) or one or more NM events (n = 29). No difference was found between these 2 groups (in DPSG, NPSG and CPG) which could allow the risk of a subsequent NM event to be predicted. The same study was done in SS: five of them subsequently had one or more NM events. No significant differences were found between SS with or without an NM event. Four SS died unexpectedly (3 diagnosed as SIDS at autopsy) with no significant abnormalities on their recordings. In any case, according to our results DPSG, NPSG and CPG recordings do not permit the risk for SIDS in any infant to be predicted.

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.