Engineers at Numotech Inc. and Sandia National Laboratories have designed a device that can reduce the healing period for many different types of wounds including plastic surgery incisions, burns, and necrotizing fasciitis. The most striking feature of the product is its simplicity, which hides the enormous amount of engineering that went into creating it. The Numobag, essentially a plastic bag in appearance, is placed around the wound and then filled with oxygen from an oxygen canister. Using the principles behind hyperbaric oxygen therapy, the Numobag infuses high concentration, high-pressure oxygen into bloodless tissue; this supply of oxygen allows the cells to repair the wound and protect against invading microorganisms. The Numobag allows wounds to receive the healing and antimicrobial benefits of hyperbaric oxygen therapy without an expensive and cumbersome traditional hyperbaric oxygen chamber. Clinical trial data for the Numobag show dramatic decreases in the healing time as well as cost to the patient, and suggest numerous uses for the Numobag outside of wound repair. As the engineers of the Numobag have illustrated, in a society of immense complexity sometimes the simplest solution is the best solution.
Introduction
To most people, a plastic bag, a hair barrette, tongue depressors, and hot glue sound like materials for an arts and crafts project--certainly not for a biomedical device; luckily, the engineers at Sandia National Labs in Albuquerque, N.M., and at Numotech Inc., in Northridge, CA, do not think like most people. Using these household items, a team of engineers from Sandia and Numotech were able to create a working prototype of a novel hyperbaric oxygen treatment system. This prototype, called the "Numobag," is the culmination of these engineers' MacGyver-like efforts to develop a new type of treatment for wounds.
The Numobag consists of a polyethylene bag that slips around the wounded area and applies concentrated oxygen athyperbaric pressures directly to a wound. The Numobag requires a canister of oxygen to supply the high oxygen concentration, while a non-electronic sensor attached to the top of the bag describes the pressure inside the bag as "good," "high," or "low." The hyperbaric pressure infuses oxygen into the wound, promotes more rapid healing, and leaves less scarring than standard wound treatment. Therapy with the Numobag benefits any type of ischemic wound, such as a burn, diabetic ulcer, pressure sore, puncture wound, or even a case of necrotizing fasciitis (flesh-eating bacteria) (Felton). However, it is not the use of oxygen therapy for wound treatment that distinguishes the engineers' design. Rather, the innovation comes from their desire to create a device that makes treatment affordable, less painful, less time-consuming, and more portable for patients suffering everything from third degree burns to diabetic ulcers. In an age where every aspect of society, especially medicine, is becoming increasingly complex, these engineers have created a technology that is overwhelmingly simple, yet incredibly effective.
Oxygen's role in keeping tissues healthy
In order to comprehend the value of a portable and disposable hyperbaric oxygen treatment system, it is imperative to understand oxygen's role in wound repair. Oxygen is a necessary component of cellular metabolism, the process that creates the energy that cells use to build and repair damaged tissue (Campbell and Reece 155-175). Any wound that disrupts the normal blood flow decreases the amount of oxygen available to tissues at the site of the wound. The first result of a decrease in oxygen levels (also referred to as "hypoxia," a lower than normal pressure of oxygen in the tissues) is compromised cellular function. The decreased amount of energy available to the cells means that they cannot keep up with the tissues' demands for energy to repair the wound. Oxygen is also required for the production of collagen, a material necessary to heal wounds (Youn).
