Comments from Carl E. Hunt, M.D.
March 25, 1998

These are very relevant data. The primary importance, however, is in relation to pathophysiology of SIDS, not the safety of airline travel for young infants.

This report is consistent with other published studies over the past 10-15 years indicating that babies at increased risk for SIDS, as a group, have decreased ability during sleep to arouse (or respond) to a low oxygen challenge. However, this cannot be used as a screening test because there is some overlap with healthy infants and the test is cumbersome and costly.

It is theoretically possible that infants at increased risk for SIDS due to decreased responsiveness to low oxygen would be at risk during air travel. However, infants are typically under close surveillance by caretakers, and any abnormal color changes (dusky, pale) would likely be alleviated by awakening the infant. A delayed effect is unlikely; infants with lower-than-normal blood oxygen levels should promptly begin to recover as soon as descent to ground level begins.

Hope this is helpful.

--by Carl E. Hunt, MD
Professor of Pediatrics at the Medical College at Ohio

Reprinted with permission from the April 1998 NW Ohio SIDS Support Network Newsletter

A recent journal publication from England has concluded that airline travel may not be safe for some infants. Researchers studied 34 healthy full term infants, 12 of whom were siblings of a prior SIDS infant. The study consisted of having the infants breathe 15% oxygen (02) overnight. This level of 02 was selected because it is about the level of 02 in the air being breathed when in a commercial airplane. Most of the infants tolerated this challenge without incident, but four infants developed prolonged and severe falls in 02 saturation and had to be placed back in normal room air (21% 02). The authors conclude that some infants may not tolerate high altitude or flying, and mention that their findings may have some relevance to SIDS.

There has never been any suggested connection between flying and risk for SIDS, and there are no reported cases of SIDS occurring in flight. Although there are some reports of SIDS in the 1-2 days following a flight, there is no physiologic (or other) reason to make a connection between those two occurrences. Whatever problem might exist in flight would progressively improve as soon as descent begins. Accordingly, this study does not provide any new information that should change any established recommendations regarding infant care in general or air travel in specific. Also of importance, the risk of SIDS in infants living at higher altitude has been studied, and no relationship has been found.

The real importance of the Southall study is in relation to numerous prior studies of breathing and arousal response to low 02 levels in infants and the hypothesis by a number of SIDS investigators (including this writer) that failure to "recognize" and hence to arouse to low 02 levels is an important (necessary??) risk factor for SIDS. Indeed, failure to arouse to low 02 and high carbon dioxide (C02) levels is a major hypothesis to explain why some infants can develop problems if they sleep face down.

In summary, the most likely explanation for the results observed in this study is that these four infants did not have normal sensing mechanisms for low 02 levels and therefore were not able to respond to this challenge by increasing their breathing volume and rate, or by awakening. Although it is theoretically possible that air travel might not be tolerated well by such infants, especially if having a respiratory infection, infants are typically under close observation in flight and SIDS has not been identified in this setting.

--by Carl E. Hunt, MD
Professor of Pediatrics at the Medical College at Ohio

Media Advisory From The SIDS Alliance about Effects Of Reductions To An Infant's Oxygen Supply Examined In New British Study; Speculation On A Possible Link Between High Altitude And SIDS Stirs Parental Turbulence Over Air Travel (3/30/98)