Air Barrier System to Reduce Contamination of Wounds During Surgery

Surgical site infection (SSI) following prosthesis implantation and other invasive procedures is a serious complication leading to increased mortality, morbidity, and financial cost to patients and the U.S. healthcare infrastructure. Multiple studies have shown that the primary source of surgical site bacterial colonization is staphylococci shed from the skin of people present in the surgical theatre. These bacteria-carrying skin cells are aerosolized into the environment and deposit into surgical incisions.

The innovations currently pursued in research and industry to combat nosocomial infection fall primarily into three categories: (1) developing new antimicrobial drugs and agents, (2) developing antimicrobial coatings for devices, and (3) implementing procedures to reduce the risk of cross-contamination. Significant resources are being allocated to prevent infections from developing post-operatively and to mitigate the effects of infection once microorganisms enter the body. However, there is little development of new technologies that can be employed in the operating room to prevent the initial intrusion into the surgery site.

All modern surgical theatres utilize some form of air filtration. In a conventional flow system, air streams mix freely in the room. In an OR designed for laminar flow (LFOR), air emits from filters and proceeds into the room in relatively coherent streams. The benefit thought to be achieved by a LFOR, in principle, is that filtered air does not mix with contaminated air before reaching the surgery area. The difficulty in achieving the desired results in a LFOR lies in the fact that once the flow pattern enters the room, it is subjected to a very complex set of dynamics over a significant distance. Air is clean upon leaving the filter bank, but it enters a space laden with airborne bacteria and particulate matter shed from people in the OR.

Nimbic Systems has developed a device, the Air Barrier System (ABS), which shields surgical sites from airborne contaminants in the operating room by creating a localized clean air field directly adjacent to and surrounding the incision site. The ABS consists of two components: a Filter and an air Nozzle with attached Hose. The Filter is a nonsterile reusable component which filters ambient operating room air and forces it through an exit port on the top of the unit. The Nozzle is attached on top of the incision drape adjacent to a surgical incision with Velcro® fastening pads. The end of the Hose is plugged into the Filter's air exit port. Contaminant-free air then flows through the Hose and Nozzle over the incision site. The ABS maintains this protective envelope of bacteria-free air over a wide range of patient and incision site geometries, yet the insertion of hands and instruments are not disrupted by the protective envelope.

The ABS technology was extremely successful at reducing the presence of bacteria and other colony forming units at incision sites during Phase I study. In a randomized, prospective clinical study of 36 hip arthroplasty procedures, the ABS reduced the presence of colony forming units at incision sites by 84% versus ambient operating room levels.