DAVID BERGELAND/Durango Herald
An inflatable pressurized bag to treat high-altitude sickness, once his only stock in trade, has become a minor item in Carl Darnell’s booming customized medical supplies business, Chinook Medical Gear.
But Darnell could become a distributor of a more sophisticated chamber using the same technology, if the military decides to use high-pressure hyperbaric medicine to treat traumatic brain injuries.
Hyperbaric therapy is medical shorthand for using oxygen at levels higher than atmospheric pressure. Among the earliest applications was treating deep-sea divers for the bends, the dangerous accumulation of nitrogen bubbles that form during decompression.
Later research focused on the technology to treat people suffering from cerebral palsy, multiple sclerosis, crush injuries, autism, wounds, burns and post-traumatic stress disorder. Much of the work is experimental and not authorized by the Food and Drug Administration.
The FDA has approved hyperbaric oxygen therapy for only 13 treatments, among them the care of wounds.
Darnell said if the FDA authorizes hyperbaric treatment for traumatic brain injury, he would distribute the high-pressure Chamberlite system manufactured by an East Coast firm.
“The FDA has not authorized hyperbaria to treat traumatic brain injury nor has it authorized the chamber,” Darnell said.
The U.S. Army is picking up on earlier medical studies of the effect of hyperbaria on brain injuries. The Army, which says 100,000 military personnel have suffered traumatic brain injury since 2003, plans an 18-month study involving 300 troops.
The theory is that increased pressure dissolves more oxygen, which can restore the function of nerve cells in the brain.
In contrast, the bag that Darnell presently offers, called the Gamow (pronounced Gam-off) Bag, provides low-pressure hyperbaria. The bag, made of urethane and named for its inventor, Igor Gamow, supplies two pounds of pressure per square inch, or one-eighth of an atmosphere, Darnell said.
The bag is 7 feet long and 21 inches in diameter.
It’s used to treat the effects of acute mountain sickness or potentially fatal high altitude pulmonary edema or high altitude cerebral edema.
On the mountain, where it’s inflated by a foot pump, the bag simulates a descent of 3,200 to 9,700 feet in altitude.
Darnell, who has climbed in Alaska, Peru and Nepal, in 2000 moved Chinook Medical Gear to Durango from the Vail area.
But the bulk of Chinook’s business today is packages or kits of medical supplies customized to meet the needs of customers such as the military, the CIA, the FBI, the Secret Service, private contractors who provide security at U.S. facilities overseas and domestic law enforcement agencies.
The Chinook catalog advertises “custom medical solutions for the harshest environments on Earth.”
Among Chinook products: kits for person-to-person blood transfusion on the front line, tourniquets, chest seals for wounds, insect repellents, skin staplers, antiseptics, bandages, airway and breathing aids, catheters and diagnostic and monitoring devices.
Darnell continues to sell and rent Gamow bags to people who face heights that challenge lungs and brain. A bag, a foot pump and a carrying case weigh 12.5 pounds.
Oxygen quickly becomes a scarce commodity on high peaks.
Air is 21 percent oxygen and 78 percent nitrogen with the remainder composed of argon and traces of helium, krypton and hydrogen. The percentage of the gases remains the same as elevation increases but there is simply less of them. In the case of oxygen, the decrease is critical.
At sea level, air has 98 percent of its oxygen; at 18,000 feet, air has 50 percent of its oxygen and at the top of Mount Everest at 29,000 feet, 30 percent.
The Wound Treatment Center at San Juan Regional Medical Center in Farmington has two hyperbaric chambers for wound treatment.
Dr. William Palko-Schraa, medical director of the wound center, said the chambers – acrylic tubes with metal frame and doors – get frequent use.
“We treat up to six patients a day,” Palko-Schraa said. “The pressure in the chambers is from 2 to 2.4 atmospheres.”
Patients typically spend two hours in what’s known among oxygen-therapy practitioners as a “dive” – a reference to deep-sea divers.
Oxygen therapy is effective because it stimulates the development of new blood vessels and promotes wound healing, Palko-Schraa said.
He cited the case of a patient who had an arm wound on which the flap of skin that was to cover the injury didn’t take. A number of oxygen-therapy sessions put the patient on the road to recovery.
Oxygen therapy is particularly useful in treating diabetic foot ulcers, Palko-Schraa said. Statistics show that with traditional treatment, a patient’s five-year risk of death from a foot ulcer is 50 percent.