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The Cooling Cure
As far back as 1000 BC, ancient civilizations used a primitive, but ingenious, cooling system using nothing more than clay pots, water, and the natural cooling power of evaporation to keep food cool. Could this same low-tech cooling system be used to prevent brain damage and cerebral palsy in developing countries? A team from Kennedy Krieger and Johns Hopkins recently developed an inexpensive medical device meant to do exactly that.
When a baby is deprived of oxygen during birth—known as asphyxia—brain function stops temporarily, and the potential for injury begins. When the asphyxia is resolved, oxygen and blood return to the brain and the neurotransmitter glutamate is released, causing seizures and a cascade of cell death, which can result in cerebral palsy, intellectual disability, or death. But there is a therapeutic window in the first six hours after birth during which brain cells can be “rescued” by lowering the infant’s core body temperature to 33.5 degrees Celsius for 72 hours. This cooling treatment, known as therapeutic hypothermia, blocks the effects of excessive glutamate and reduces seizures, which can reverse the process of cell death. At the end of the cooling period, the baby is slowly rewarmed until a temperature of 36 degrees Celsius is reached.
In three major controlled clinical trials based in the United States, London, and New Zealand, this method of therapeutic hypothermia using a cooling blanket system has been found to reduce the incidence of cerebral palsy by 40 percent and is now becoming the standard care of treatment for newborn asphyxia. While this treatment has proven effective for reducing the damage from asphyxia in the United States and other developed countries with substantial healthcare resources, the technique is not widely available in developing countries because it is expensive and requires a stable source of electricity.
According to the World Health Organization, the rate of asphyxia in developing countries is as high as 1.5 percent in newborns. Women may not have access to prenatal care, which can result in anemia, infection, maternal malnutrition, and premature delivery, all of which can lead to asphyxia. It is estimated that 40 to 50 percent of cases of cerebral palsy in developing countries are the result of asphyxia.
Dr. Michael Johnston—renowned research scientist, executive vice president, and chief medical officer at Kennedy Krieger Institute—has been studying ways to provide neuroprotection for infants with asphyxia for more than 25 years, with the support of NIH grants to Kennedy Krieger Institute. During a visit to Egypt in 2010, he gave a lecture on therapeutic hypothermia at an international conference on brain injury, and one of the doctors in the audience asked if a window fan could help cool babies, since they did not have access to the expensive equipment used in the U.S. That question planted the seed for Dr. Johnston to begin thinking about how developing countries could have access to a better method for treating babies with asphyxia.
When he returned, he discussed the question with pediatric neurologist and postdoctoral fellow Dr. Ryan Lee, who, at the suggestion of a bioengineer acquaintance, proposed submitting the problem to the Johns Hopkins University Center for Bioengineering Innovation & Design. Undergraduate bioengineering student John Kim selected the project, assembled a team of other undergraduate students at Johns Hopkins, and set about designing a solution. Dr. Johnston and Dr.Lee served as clinical advisors to Kim and his team, and guided them through the development of the device.
The resulting invention was a cooling system that relies on clay pots, water, and evaporation, and appeared to provide essentially the same neuroprotective results as the standard therapeutic hypothermia equipment used in U.S. hospitals when tested in newborn piglets. The prototype was modified to add a plastic-lined burlap basket and works by placing wet sand, urea-based cooling powder, and water in the clay pot. As the water evaporates, heat is transferred away from the basket, resulting in a lower temperature inside the basket.
The student-designed device can be assembled for under $40—a fraction of the $12,000 cost of the standard equipment—and it can be powered by two AAA batteries, rather than alternating current, which is often unreliable in resource-poor countries. The device is equipped with simple LED lights that flash if overheating or overcooling occurs, making it easy to use in neonatal intensive care units in developing countries, where the ratio of nurses to babies could be as high as 40 to one.
The team published their study on the new device in December in the journal Medical Devices: Evidence and Research. The device, called the “Cooling Cure,” is patent-pending, and the team is in the process of writing a grant proposal for clinical testing in India and Canada.
Based on the positive results, the team hopes this will be the first of many projects bringing together the fields of bioengineering and medicine at the Institute. The team already has a new project in the works—development of a cost-effective device for monitoring cardiac and respiratory function in infants.