Head turning and face-down positioning in prone-sleeping premature infants.

BACKGROUND: Term infants may die of sudden infant death syndrome (SIDS) when they assume the face-straight-down or the face-near-straight-down head positions. Preterm infants have a higher SIDS rate, but it is not known how often they assume the face-straight-down and face-near-straight-down positions. OBJECTIVES: To determine the frequency and cardiorespiratory consequences of head turning and face-down head positioning in prone-sleeping premature infants. STUDY DESIGN: Supervised overnight cardiorespiratory and audiovisual recordings were conducted in 15 prone-sleeping preterm infants nearing hospital discharge: birth weight, 1178 101 (SEM) g, postconceptional age, 40 1.0 weeks. RESULTS: The preterm infants, studied at a younger postconceptional age than previously reported term infants, seldom turned their heads during sleep; therefore they rarely assumed the face-straight-down position (6 episodes in 3 infants) or the face-near-straight-down position (30 episodes in 6 infants). CONCLUSIONS: Prematurely born infants, known to be at increased risk of SIDS, rarely assume face-down positions when sleeping prone at approximately 40 weeks' postconceptional age. These results suggest that head turning during sleep is developmentally regulated and may have relevance to understanding the age distribution of SIDS.

Sleep-disordered breathing in children with myelomeningocele.

BACKGROUND: Although patients with myelomeningocele and the Chiari II malformation are known to have sleep apnea and respiratory control deficits, the prevalence, types, severities, and associations of sleep-disordered breathing (SDB) have not been adequately defined. METHODS: A cross-sectional study of our myelomeningocele clinic population was undertaken to correlate polysomnographic results with historical data and findings from magnetic resonance imaging of the Chiari malformation, pulmonary function results, and nocturnal pulse oximetry. RESULTS: A questionnaire survey of symptoms was available for 107 of 109 children (98% of the clinic population), and 83 patients agreed to undergo overnight polysomnography. Breathing during sleep was classified as normal in 31 cases (37%), mildly abnormal in 35 cases (42%), and moderately/severely abnormal in 17 cases (20%). Among the 17 patients with moderately/severely abnormal SDB, 12 patients had predominantly central apneas and 5 had predominantly obstructive apnea. Patients with a thoracic or thoracolumbar myelomeningocele, those who had previously had a posterior fossa decompression operation, those with more severe brain-stem malformations, and those with pulmonary function abnormalities were more likely to have moderately/severely abnormal SDB, relative risks (95% confidence intervals) 9.2 (2.9 to 29.3), 3.5 (1.3 to 8.9), 3.0 (0.9 to 10.5), and 11.6 (1.6 to 81.3), respectively. Failure of obstructive SDB to resolve after adenotonsillectomy in four patients suggested abnormal control of pharyngeal airway patency during sleep. Nocturnal pulse oximetry accurately predicted moderately/severely abnormal SDB with a sensitivity of 100% and a specificity of 67%. CONCLUSIONS: The pathogenesis of SDB in patients with myelomeningocele involves the functional level of the spinal lesions, congenital and acquired brainstem abnormalities, pulmonary function abnormalities, disorders of upper airway maintenance, and sleep state. Polysomnography and nocturnal pulse oximetry should be performed in high-risk patients to detect and classify SDB.

Face-straight-down and face-near-straight-down positions in healthy, prone-sleeping infants.

OBJECTIVE: To determine the frequency and physiologic consequences of the face-straight-down (FSD) position, a postulated mechanism for the sudden infant death syndrome in prone-sleeping infants. STUDY DESIGN: A survey of 151 infants, aged 1 to 7 months, in Montreal showed that 33% slept prone. Ten healthy prone-sleeping infants were studied in their homes at age 10 to 22 weeks. Infrared video and cardiorespiratory recordings were made on 3 consecutive nights in the prone (nights 1 and 3) and lateral (night 2) positions. RESULTS: Infants maintained the prone position during 17 of 19 studies, but only 4 of 9 infants maintained the lateral position. The FSD position was observed 27 times in 17 prone nights: median frequency, 0.6 times per night (interquartile range, 0 to 4), and median total duration, 3.3 minutes (0.8% of total sleep time). A related position, the face-near-straight-down (FNSD) position, occurred more often, 5.3 (1 to 10) time per prone night, for 22.4 minutes (5.8% of total sleep time). Most periods in the FSD and FNSD position had no physiologic consequences; however, 14% of FSD and 3% of FNSD episodes were associated with airway obstruction as indicated by snoring, paradoxical respiratory movements, apnea, and/or increased partial pressure of transcutaneous carbon dioxide. Spontaneous arousal and head turning terminated the FSD and FNSD episodes. CONCLUSION: The FSD and FNSD positions occur commonly in healthy prone-sleeping infants, and these positions can cause airway obstruction. We speculate that those infants with sudden infant death syndrome found in the FSD or FNSD position either have a congenital or an acquired defect in the arousal-head turning response or have encountered insurmountable environmental factors that prevent effective head turning.