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.