Medical Device & Diagnostic Industry Magazine
MDDI Article Index

Originally Published March 2000

COLD-WEATHER FORECAST

Ani Grigorian

John Dobak, MD, founder, president, and CEO of Innercool Therapies Inc. (San Diego), was unexpectedly introduced to the field of cryosurgery nearly five years ago after a mishap occurred in a clinic where he was working.

As a medical student at the University of California, San Diego (UCSD), Dobak was assigned to "work detail" in a dermatology clinic where he spent his days freezing patients' warts with dabs of liquid nitrogen. "I spilled all of the liquid nitrogen we had for the day," he relates. "They were annoyed with me so they told me to remove the warts by zapping them with electricity from a device that plugged into the wall. I started thinking why don't they have a cryo-device that I could plug into the wall and zap things with instead of having to use this archaic liquid-nitrogen process?"

Dobak's entrepreneurial skills and scientific insights have led to a number of significant innovations.

In 1994, Dobak founded CryoGen Inc. (San Diego) and focused on developing a cryosurgical device for cardiac arrhythmia and endometrial ablation. Available devices were large, complicated, and costly: "With the older systems of cryosurgery, liquid nitrogen—which has a very narrow transition temperature from liquid to gas—would have already flashed to its gas state by the time it reached the probe tip. The gaseous nitrogen can't absorb nearly as much heat as its liquid counterpart." Dobak recognized that the drawback to these systems was their extreme insulation requirements, their large size—which he explains, earned them the nickname "Zamboni"—and the fact that they necessitated a constant replenishment of liquid nitrogen.

In response to the problems that Dobak had identified, CryoGen introduced a miniaturized, closed-cycle cryoablation device and supporting system that allowed physicians to ablate tissue at very low temperatures. The company used a unique coolant, which was a mixture of gases rather than conventional liquid nitrogen. "By using these complex mixtures, we developed the capability for extreme cooling at relatively low pressures. Instead of having 800 psi in a tank to lower temperatures to –50°C, now we could have 300 psi in an oil-free compressor and induce temperatures as low as –120°C." The portable Joule-Thomson–type system recirculated the gases being used, and all of the cooling took place at the powering end of the device, which prevented insulation problems and the need for frequent replacement of the gases.

Having read an article about a boy who was resuscitated after submersion in a frozen lake for 45 minutes, Dobak decided to apply the effects of hypothermia therapeutically to interfere with the "ischemic cascade" of tissue that occurs when tissue is deprived of oxygenated blood. He developed a number of concepts and ideas that he was able to build upon, aided by the engineering expertise of Juan Lasheras, PhD, chair of UCSD's mechanical and aerospace engineering program. The result was the founding of Innercool Therapies Inc. and the development of a hypothermic catheter designed to diminish brain damage in stroke patients by gently cooling the blood on its way to the brain.

Beginning his first venture at Innercool early in 1998, Dobak describes the company's goal as developing, manufacturing, and marketing vascular catheters that are capable of promptly and safely inducing and then reversing hypothermia to treat stroke and heart-attack patients. "The technology works by direct blood-heat transfer," Dobak explains. "A catheter is placed into an artery or vein of the body, and circulating saline cools the special proprietary tip of the catheter while energy is absorbed from the blood, causing it to cool as it flows over the tip." The technology essentially eliminates the need for surface-heat-transfer methods, such as cooling or warming blankets. Dobak expects to initiate clinical trials for this new technology later this year.

Recently selected by Technology Review magazine as one of the 100 young men and women most likely to make innovative contributions to technology in the 21st century, Dobak has discovered from his experience that there isn't a cookbook recipe for developing new cryosurgical or hypothermic products. He maintains that the field of cryotherapy is in need of individuals with unique skills that may not necessarily be attainable through a traditional engineering degree. "A lot of what you need to know has to be learned through apprenticeship, but there's a lot of potential and plenty of growth and opportunity in this field."

Ani Grigorian is editorial assistant of MD&DI.