Behaviour and physiological responses during prone and supine sleep in early infancy

Abstract

Aims-To study the eVect of prone and supine sleep on infant behaviour, peripheral skin temperature, and cardiorespiratory parameters to aid understanding of why prone sleeping is associated with an increased risk of sudden infant death syndrome. Methods-Of 33 enrolled infants, 32 were studied at 2.5 and 28 at 5 months of age. A computer aided multichannel system was used for polysomnographic recordings. Behaviour was charted separately. Results-Prone REM (active) sleep was associated with lower frequencies of short arousals, body movements and sighs, and a shorter duration of apnoeas than supine REM sleep at both ages. At 2.5 months there were less frequent episodes of periodic breathing during prone sleep in non-REM (quiet) and REM sleep. Heart rate and peripheral skin temperature were higher in the prone position during both sleep states at both ages. Conclusions-The observation of decreased variation in behaviour and respiratory pattern, increased heart rate, and increased peripheral skin temperature during prone compared with supine sleep may indicate that young infants are less able to maintain adequate respiratory and metabolic homoeostasis during prone sleep. (Arch Dis Child 1997;76:320-324) Keywords: behaviour; sudden infant death syndrome; sleeping position Prone sleeping, overwrapping, heating of the bedroom, and other infant care practices which may increase body temperature are reported risk factors for sudden infant death syndrome (SIDS).1-4 There seems to be a causal relation between prone sleeping and SIDS, but the terminal, pathophysiological mechanisms causing death are largely unknown. Lack of a normal arousal response 5 or suVocation due to airway obstruction or rebreathing of carbon dioxide from a face down position [6][7][8][9][10] have been suggested as contributory mechanisms. Although epidemiological studies have shown that there is an association between overwrapping and increased environmental temperature, and SIDS, the mechanisms of interaction are not understood.2 4 The issue is complicated further as overheating seems to be a risk factor particularly or exclusively for infants sleeping prone. 4The purpose of the present study was to compare supine and prone sleeping in early infancy with respect to sleep related behaviour, peripheral body temperature, and cardiorespiratory responses in a warm environment to add understanding to why prone sleeping is a major risk factor for SIDS. Subjects and methods SUBJECTSThirty three infants (17 girls and 16 boys) were recruited for an overnight sleep study. Only term infants (at least 37 weeks' postconceptional age) without prenatal or perinatal complications were included. No infant with a positive history of family diseases, apparently life threatening events, or cases of SIDS in siblings was allowed. The mean birth weight was 3631 g (range 2870-4840 g) and all infants were healthy at the time of the study.A questionnaire containing information on infant care practices such as feeding, preferred sleeping position, sleep environment, ...

Cerebral Oxygenation in Preterm Infants

“…It is well established that prone sleeping is associated with an increase in temperature and peripheral vasodilation in infancy. 20,45,46 This reduction in peripheral vascular resistance stimulates a baroreflex-mediated increase in HR to maintain MAP. 19,45 This reflex response is consistent with our observations at 2 to 4 weeks and 5 to 6 months CA, where HR and temperature were increased in the prone position and MAP was maintained.…”

“…20,45,46 This reduction in peripheral vascular resistance stimulates a baroreflex-mediated increase in HR to maintain MAP. 19,45 This reflex response is consistent with our observations at 2 to 4 weeks and 5 to 6 months CA, where HR and temperature were increased in the prone position and MAP was maintained. In contrast, we found no increase in HR in the prone position at 2 to 3 months CA, despite the observed increase in temperature; this coincided with a tendency for MAP to be lower in the prone compared with the supine position.…”

Spontaneous Arousals in Supine Infants While Swaddled and Unswaddled During Rapid Eye Movement and Quiet Sleep

“…Supine sleeping is associated with increased arousals from sleep compared with the prone sleep position. [5][6][7][8][9] The effect of swaddling on the frequency of brainstem arousals as well as full behavioral arousals is unknown. Likewise, the effect of swaddling on progression of brainstem arousals to full arousals is unknown.…”

“…4 Studies confirm that the prone position decreases frequency of arousals. [5][6][7][8][9] Swaddled infants placed on their backs are said to "sleep better," presumably meaning that they sleep longer or with fewer arousals. Parents commonly report that infants who are back sleepers "startle themselves awake."…”

Use of Positioning to Reduce the Severity of Neonatal Narcotic Withdrawal Syndrome

“…7,8 Over the past 25 years, numerous studies have confirmed that infants laid prone enjoy a range of behavioral and physiological advantages. The positive consequences of prone position for sleep include: fewer awakenings and increased time in quiet sleep, 9,10 more sleep with higher arousal thresholds, [11][12][13] lower levels of activity, 14,15 enhanced respiratory control, 16 -18 and diminished heart rate variability. 11,17 Newborns laid prone cry much less than supine-lying infants 11 and have decreased energy requirements.…”