Researchers Designing Safer Cryotherapy Devices

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

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 extremely cold temperatures 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 US each year, according to UTA researchers.

Preliminary research has shown that a 30 minute cryotherapy session causes an approximate 90 percent reduction in blood flow to the treated area, a condition that 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,” says Matthew Brothers, an associate professor of kinesiology in the UTA College of Nursing and Health Innovation and co-investigator on the project. “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.”

Extreme practitioners can, without formal protocols, 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. Cryotherapy procedures have recently attracted both public notoriety and increased popularity, as opinions regarding it have fluctuated following the death of a cryotherapy esthetician in Nevada and in the wake of multiple celebrity endorsements.

Several members of the Super Bowl Champion Denver Broncos, for example, routinely use cryotherapy to both recover from and prepare for football games. In a video posted to YouTube, players can be seen prancing about a cryochamber, inhaling vapors escaping from the unit and in one case even operating the cryochamber for the segment’s reporter. “I’m not trained,” says Bronco linebacker Brandon Marshall, before activating the chamber and lowering its temperature. “I did negative 300; you’re doing negative 400, though.”

Such a casual disregard for safety highlights the need for industry-wide guidelines and best practices.

“It is striking that there are currently no protocols for the use of cryotherapy devices despite awareness of risks to patients,” says Anne Bavier, dean of the College of Nursing and Health Innovation at UTA.

In addition to developing protocols and a prototype device, Brothers and his co-investigator Kenneth Diller, a University of Texas at Austin professor of biomedical engineering, are also 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.

The work is supported by a four-year, $1.1 million grant from the National Institutes of Health. In Austin, about 800 patients have registered for the study, and registration is scheduled to begin this month in Arlington. “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,” says Bavier.