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根据发表于12月小儿科期刊的研究结果，睡眠时的血压变化可能与发生婴儿猝死症(SIDS)有关。
澳洲Monash大学Ritchie婴儿健康研究中心的Nicole B. Witcombe等人写道，早产婴儿的SIDS风险增加，可能是因为心律与血压自体控制不成熟；之前的研究显示，早产婴儿的心律和血压与校正年龄组不一样；不过，有关这个年纪的资讯有限。本研究的目标是确认早产者在出生后6个月内、与达到校正年龄后之心律与血压，包括增加SIDS风险的年纪，以了解SIDS的病理。
研究针对25个早产儿和20个周产儿在2至4周、2至3个月、5至6个月校正年龄时进行日间多频道睡眠记录；在婴儿的手腕运用光体积描绘图讯号(Finometer, Finapres Medical Systems BV公司) 测量安静与活动睡眠时的血压。
研究的所有年纪中，早产组在安静与活动睡眠时都有较低的血压，但是两组的心律没有差别。对于早产组的婴儿，校正年龄2至3个月时的平均血压比校正年龄2至4周和5至6个月时低，各年纪安静睡眠时的血压都比活动睡眠时低。心律随着年纪增加而降低。在5至6个月校正年龄时，安静睡眠时的心律低于活动睡眠时。
研究作者写道，睡眠状态与年纪影响早产婴儿校正年纪6个月内心律与血压模式；值得注意的是，早产婴儿之平均血压比年纪相仿的足月婴儿低，意味着对于早产婴儿的心血管控制要有长期的改变。
研究限制包括研究样本之异质性；研究中的25个婴儿有3个生产时比怀孕周数小；根据概念年纪进行足月与早产婴儿之配对，早产婴儿SIDS风险最大的时期发生在比研究中的2至3个月更早的时候。
研究作者结论表示，我们在早产和足月婴儿之间的血压发现显著差异，这可能是因为早产儿之SIDS风险增加。需要进行睡眠时心血管变化与检视重觉反射反应的后续研究，以进一步了解早产婴儿是否在出生后初期有不佳的心血管控制。这些研究或许可以进一步解释早产儿SIDS风险增加的机转，以及了解未来对心血管系统的影响。
澳洲国家健康与医学研究委员会支持本研究。作者宣称没有相关资金上的往来。
Blood Pressure Changes During Sleep May Be Related to SIDS
By Laurie Barclay, MD
Medscape Medical News
Blood pressure changes during sleep may be related to development of sudden infant death syndrome (SIDS), according to the results of a study published in the December issue of Pediatrics.
"Preterm infants are at an increased risk of , which may result from immature autonomic control of heart rate and blood pressure," write Nicole B. Witcombe, BSc, from the Ritchie Centre for Baby Health Research at Monash University in Melbourne, Victoria, Australia, and colleagues. "Previous studies have demonstrated that preterm infants have altered heart rate and blood pressure control at term-equivalent age; however, little information is available beyond this age. The aim of this study was to determine the effect of preterm birth on heart rate and blood pressure control over the first 6 months of life after reaching term-equivalent age, including the age at which risk is increased, to understand the pathogenesis of ."
Daytime polysomnography was performed in 25 preterm and in 20 term infants at 2 to 4 weeks, 2 to 3 months, and 5 to 6 months of term-corrected age. A photoplethysmographic cuff (Finometer, Finapres Medical Systems BV) applied around the infant's wrist measured blood pressure during quiet and active sleep.
At all ages studied, the preterm group had lower blood pressure during both quiet and active sleep, but heart rate did not differ between groups. For the infants in the preterm group, average blood pressure was lower at 2 to 3 months' corrected age than at 2 to 4 weeks' and 5 to 6 months' corrected age and was lower in quiet sleep than in active sleep at all ages studied. Heart rate decreased with increasing age. At 5 to 6 months' corrected age, heart rate was lower in quiet sleep than in active sleep.
"Sleep state and age affect heart rate and blood pressure patterns in prematurely born infants over the first 6 months of term-corrected age," the study authors write. "It is notable that preterm infants had persistently lower blood pressure compared with age-matched term infants, signifying long-term alterations in cardiovascular control in infants born prematurely."
Limitations of this study include heterogeneity of the study sample; that 3 of the 25 infants studied were born small for gestational age; and matching of term and preterm infants for conceptual age, even though the period of peak SIDS risk in preterm infants occurs at an earlier conceptual age than the 2 to 3 months' age studied.
"We identified significant differences in [blood pressure] between preterm and term infants that may contribute to the increased risk of SIDS in preterm infants," the study authors conclude. "Additional studies examining baroreflex responses and cardiovascular variability during sleep are required to further understand whether preterm infants have impaired cardiovascular control during the early postnatal period. These studies may further explain the mechanisms involved in the increased risk for SIDS associated with preterm birth and the impact that this may have on the cardiovascular system later in life."
The National Health and Medical Research Council of Australia supported this study. The authors have disclosed no relevant financial relationships.
Pediatrics. 2008;122:e1242–e1248.