Researchers developing cryotherapy device to reduce tissue damage

Cold therapy has long been prescribed for those recovering from orthopedic surgery, muscle inflammation and sports-related injuries, with treatments ranging from ice baths to immersion in whole-body cryotherapy chambers.

Yet the risks to exposed skin and blood vessels constricted by temperatures of 50 degrees Fahrenheit or below can be severe, leading in some cases to nerve and tissue damage, neuropathy and more serious impacts on the treated limb. Between 1,500 and 2,000 cases of such injuries are reported in the U.S. each year.

Researchers at The University of Texas at Arlington and The University of Texas at Austin are developing a solution in the form of what are believed to be the first formal protocols for effective and safe use of cold therapy, and a state-of-the-art cryotherapy device that can stimulate blood flow to keep tissue healthy and minimize potential side effects.

Matthew Brothers, an associate professor of kinesiology in the UTA College of Nursing and Health Innovation, is co-investigator on the project. The work is supported by a four-year, $1.1 million grant from the National Institutes of Health. Brothers and his co-investigator Kenneth Diller, a University of Texas at Austin professor of biomedical engineering, alongside other colleagues, have filed a provisional patent application for the innovative technology that will result from their work. The team may secure additional funding as they achieve results.

Currently, about 800 Austin area patients are participating in the formal testing process. Recruitment in the Arlington area is scheduled to begin in February.

Preliminary research has shown that a 30-minute cryotherapy session causes an approximate 90 percent reduction in blood flow to the treated area, which continues for up to three hours after the treatment is over and skin temperatures have returned to the pre-cooling levels.

"This pronounced and sustained reduction in blood flow, which lowers the delivery of oxygen and nutrients to the treated area, contributes to these side-effects," said Brothers, who joined UTA in 2015. "Our research will establish the optimal times and temperatures for treatment and test ways to stimulate blood flow to the treatment area. We will also develop new devices that apply cold directly to the treatment site to increase the precision of care."

Currently, without formal protocols, extreme practitioners can advocate continuous use of cryotherapy for days and even weeks while others recommend an application period of 20 to 30 minutes followed by a cessation period of two hours.

In addition to developing protocols and a prototype device, the team also is investigating the physiological mechanisms behind the reductions in blood flow, through a series of experiments that involve infusing different substances that impact the regulation of blood vessels. These substances range from antioxidants to ones that block the response of sympathetic nerves that cause vasoconstriction. Changes in blood circulation are then measured using a laser Doppler probe to determine the reasons behind the reductions in blood flow.

Anne Bavier, dean of the College of Nursing and Health Innovation, commended the initiative as a model of the University's work to advance Health and the Human Condition under the Strategic Plan 2020: Bold Solutions | Global Impact.

"It is striking that there are currently no protocols for the use of cryotherapy devices despite awareness of risks to patients," Bavier said. "This valuable work will provide the knowledge and new technologies needed to ensure patient safety while providing the benefits that cooling treatments have been known for since the time of Hippocrates."