Waters K A, Gonzalez A, Jean C, Morielli A, Brouillette R T
Department of Pediatrics, McGill University, Montreal, Quebec, Canada.
J Pediatr. 1996 May;128(5 Pt 1):616-25. doi: 10.1016/s0022-3476(96)80125-9.
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.
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.
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.
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.
确定脸朝下（FSD）体位的发生频率及其生理后果，这是一种推测的俯卧睡眠婴儿发生婴儿猝死综合征的机制。
对蒙特利尔151名1至7个月大的婴儿进行的一项调查显示，33%的婴儿俯卧睡眠。对10名健康的俯卧睡眠婴儿在其10至22周龄时在其家中进行研究。在连续三个晚上分别记录婴儿处于俯卧位（第1和第3晚）和侧卧位（第2晚）时的红外视频和心肺功能。
在19次研究中有17次婴儿保持俯卧位，但9名婴儿中只有4名保持侧卧位。在17个俯卧睡眠的晚上共观察到27次FSD体位：中位频率为每晚0.6次（四分位间距为0至4），中位总时长为3.3分钟（占总睡眠时间的0.8%）。一种相关体位，即脸接近朝下（FNSD）体位，出现得更频繁，每个俯卧睡眠晚上出现5.3次（1至10次），时长为22.4分钟（占总睡眠时间的5.8%）。大多数处于FSD和FNSD体位的时间段没有生理后果；然而，14%的FSD体位发作和3%的FNSD体位发作与气道阻塞有关，表现为打鼾、矛盾呼吸运动、呼吸暂停和/或经皮二氧化碳分压升高。自发觉醒和转头终止了FSD和FNSD体位发作。
FSD和FNSD体位在健康的俯卧睡眠婴儿中很常见，并且这些体位可导致气道阻塞。我们推测，那些在FSD或FNSD体位被发现患有婴儿猝死综合征的婴儿，要么在觉醒 - 转头反应方面存在先天性或后天性缺陷，要么遇到了无法克服的环境因素，阻止了有效的转头。
