A new study by researchers with Kaiser Permanente Northern California suggests a simple strategy for reducing the risk of sudden death of infants in their sleep: turning on a fan at night.

The study's findings, based on data collected from nearly 500 mother-and-child pairs in California between 1997 and 2000, indicate that the use of a fan in an infant's room may reduce the likelihood of sudden death by 72%. But the data suggest that the protective effect applies mostly to babies in poor sleeping environments — those who are put to bed in overheated rooms or on their stomach.

The National Institute of Child Health and Human Development (NICHD) issued a statement in response to the study, published Oct. 6 in the Archives of Pediatrics & Adolescent Medicine, warning that "that there is no substitute for the most effective means known to reduce the risk of [sudden infant death syndrome, or] SIDS: always placing infants for sleep on their backs."

The NICHD's federally funded "Back to Sleep" campaign, which advocates for putting babies to sleep face-up, has helped reduce the national SIDS death rate 56%, from 1.2 deaths per 1,000 live births in 1992 to .53 deaths per 1,000 live births in 2003. In addition to placing babies on their backs to sleep, pediatricians recommend that parents use firm mattresses for babies, avoid soft bedding such as comforters and quilts, put babies in their own cribs at night, keep infants from overheating and refrain from smoking during pregnancy and infancy.

Indeed, the study's authors say that caretakers who followed established safety guidelines were less likely overall to suffer the sudden death of a child, compared with those who tended not to take the same precautions. The study also found that when fans were used in the absence of other environmental risk factors — that is, when parents already had other safeguards in place — it had no significant additional impact on the risk of SIDS.

"If the baby was already in a good sleeping environment, there wasn't very much chance they were 'rebreathing,'" says Dr. De-Kun Li of Kaiser Permanente's Division of Research and a co-author of the study, referring to the re-inhalation of carbon dioxide that is associated with sudden unexplained death. "So it's not surprising that adding a fan, or not, didn't make that much difference."

The benefit of a fan became apparent, however, when it was used in sleep environments typically associated with a higher risk of SIDS. For example, researchers found that fans were associated with a 94% reduction in SIDS risk for babies who slept in rooms that exceeded 70 degrees F (21 degrees C); an 85% reduction for infants in rooms with closed windows; an 86% reduction among babies placed on their sides or stomach to sleep; and a 78% reduction among those who did not use a pacifier (the pacifier's handle is hypothesized to help maintain babies' breathing space under a blanket or in soft bedding).

"If you decrease the chance of rebreathing exhaled air, your SIDS rate is going to be reduced, says Li. "Using a fan is one way."

Betty McEntire, executive director of the American SIDS Institute, says the study is useful for underscoring the link between SIDS and rebreathing or overheating. "We know that increased carbon dioxide can hurt the baby's ability to arouse during sleep," says McEntire. "So you definitely want to prevent your baby from rebreathing and overheating."

"Chipping away at the SIDS problem is important," McEntire continues, "and this study adds a little bit [of clarity] to the puzzle."

The etiology of SIDS is still largely a mystery. To date, perhaps the best evidence of its cause comes from a 2006 study led by researchers at Children's Hospital Boston, who examined the brain tissue of babies who died from SIDS and those who died from other causes. Researchers found that SIDS babies often have a brain defect in a region of the brain that controls breathing, heart rate and blood pressure. The abnormality appears to weaken the responsiveness of certain functions, including arousal from sleep when the body fails to get enough oxygen. Researchers think the defect may be genetic in origin, although there are no biological tests yet to determine risk.

For now, the study's authors agree that the best way to reduce the likelihood of SIDS — the leading cause of death among American infants aged under 1 year, which kills more than 2,000 infants each year — is through environmental safety measures put forth by the American Academy of Pediatrics. Using a fan, Li says, "can provide concerned parents an extra measure to reduce SIDS."

北加州凱瑟醫療中心的研究人員最新的發現表明減少嬰兒突然死亡的一個簡單的辦法就是：在孩子晚上睡覺的時候打開風扇。

這項研究搜集了1997年到2000年之間加州的將近500對母子的資料，研究成果表明在嬰兒的房間內使用風扇可以減少72%的死亡率。但是數據顯示這樣的保護措施大多是孩子睡眠環境不好時——像那些房間過熱，或者趴著睡的孩子。

國家兒童保健和人類發育研究所針對這個研究發表了一份聲明（登在10月6日出版的兒童和青少年醫學雜志上），警告說沒有機構對現在知道的最有效的減少嬰兒猝死的辦法——讓孩子平躺著睡覺更好的辦法了。

國家兒童保健和人類發育研究所在全聯邦范圍內發起“平躺著睡覺”運動，此運動提倡讓孩子面朝上入眠，這已經把全國嬰兒猝死率減低了565,從1992年的1，000個人中有1.2人死亡到

2003年底餓1，000人中0.53人死亡。除了讓孩子平躺著睡覺之外，兒科醫生還推薦父母給孩子用的床墊不要太軟，避免像靠墊，被子之類物品，晚上把孩子放到嬰兒床上，遠離過熱的環境，而且在懷孕期間，幼兒期內要遠離香煙。

其實，這項研究的主編說看護人只要按照既有的安全向導做事根本不可能使孩子猝死的，這可以和沒有預防心里的人做個比較。這項研究同時還發現如果父母在已經有預防措施的房間里使用風扇的話，這種做法對嬰兒猝死是沒有影響的。

“如果孩子的睡眠環境良好，那就沒有必要換氣了。”談到和無法解釋的猝死相關的二氧化碳二次吸入時，凱瑟醫療研究分部李德坤醫生說到，他也是這個研究的副編。

然而，在典型的造成嬰兒猝死的睡眠環境中，風扇的作用顯而易見，比如，研究者發現風扇在嬰兒睡眠的房間溫度超過華氏71度（攝氏21度）是，可以把死亡率減少94%；在關著窗戶的屋子里可以減少85%；在趴著睡覺的孩子中可以減少86%，與沒有使用奶嘴的手柄的孩子相比可以減少78%（奶瓶被被假設為孩子在毯子下或軟床上是的呼吸空間）。

如果減少呼入已經呼出的氣體，嬰兒猝死率將會得到減少，李說“使用風扇是個辦法。”