Keeping a Cool Head May Prevent Brain Injuries in Newborns

A new head-cooling device aims to prevent or reduce the severity of hypoxic-ischemic encephalopathy (HIE) — a potentially fatal brain injury in the newborn caused by inadequate blood flow or by oxygen deprivation during labour or delivery.

How It Works

The Olympic Cool-Cap® device uses selective head cooling to lower the body temperature by three degrees Celsius and induce a state of mild hypothermia. Cold water circulates through a fitted cap, while the newborn is kept under a radiant warmer to maintain a rectal temperature of 34ºC to 35ºC.[1]

Cooling is thought to help prevent the neurological damage that continues to occur over a period of hours or days following oxygen deprivation. Brain cooling must be initiated within six hours of the initial injury and maintained for 72 hours.

Who Might Benefit

An estimated one to two babies per 1,000 term live births are at risk of HIE.[1] About 25% to 30% of babies who survive HIE will be left with lifelong disabilities, such as cerebral palsy, seizure disorder, and cognitive disability.[2] No other current therapies exist to improve the outcome from HIE, beyond supportive care and anticonvulsants for seizure control.[3]

Regulatory Status

The Olympic Cool-Cap is manufactured by Olympic Medical Corporation, a subsidiary of Natus Medical Incorporated, in San Carlos, California. Cool-Cap was licensed by Health Canada in October 2006. It received US Food and Drug Administration pre-market approval in December 2006 for use in full-term infants with clinical evidence of moderate to severe HIE.

Evidence

An industry-sponsored, randomized controlled study of 234 full-term infants with moderate to severe HIE and an abnormal amplitude-integrated electroencephalogram (aEEG) compared the effects of head cooling for 72 hours against a non-cooled group who received supportive care.[1] Of 108 infants treated with Cool-Cap, 59 died or suffered severe disability by the time they were 18 months old, compared with 73 of 110 infants in the control group. This corresponded to an 11% absolute rate reduction in death or major disability, which was not statistically significant (p=0.10). However, in a predefined subgroup analysis, when 46 infants with the most severe aEEG changes were removed from the analysis, head cooling resulted in a statistically significant, 18% absolute rate reduction of death or disability in 172 infants with less severe aEEG abnormalities (p=0.009).

Longer-term outcomes, such as cognitive function at school age, are currently unknown. Several studies investigating the use of whole body cooling for the treatment of HIE are now underway.[4,5]

Adverse Events

With Cool-Cap treatment, temporary scalp swelling, slowed heart rate, and a modest rise in plasma glucose occurred, but these were not clinically significant.[1]

Cost

Neither the capital cost for the Cool-Cap device, nor the cost for single-use caps and temperature sensors, were available at the time of writing this article.

References

[1] Gluckman PD, et al. Lancet 2005;365(9460):663-70.
[2] Lin ZL, et al. J Perinatol 2006;26(3):180-4.
[3] Wyatt JS, et al. Early Hum Dev 2005;81(1):5-11.
[4] Cooke R. Lancet 2005;365(9460):632-3.
[5] Higgins RD. Obstetrics & Gynecology 2005;106(6):1385-7.