Factors affecting emission collection by surgical smoke evacuators.
Smith JP; Topmiller JL; Shulmann S
Lasers Surg Med 1990 May/Jun; 10(3):224-233
Factors affecting emission collection by smoke evacuators during surgical procedures were examined. A commercial smoke collector having a 20 to 40 cubic feet per minute flow rate and fitted with a 2 by 0.5 or 6 by 0.5 inch (in) nozzle was tested. The effects of evacuator flow rate, distance from the evacuator nozzle to the surgical site, and direction and speed of the external air flow relative to the nozzle flow on collection efficiency were investigated. A continuous wave surgical carbon-dioxide laser was used in a simulated surgical procedure with a mannequin or to cut a 1in thick piece of steak or hamburger. The latter involved a tracer gas technique. The laser operated at power settings of 30, 60, or 100 watts (W). Collection efficiency was significantly greater at high nozzle flow rates than at low flow rates. Collection efficiencies for nozzle and external air flow angles of zero with both flows going in the same direction were close to 100%. As the angle of external air flow relative to nozzle flow increased, the collection efficiency decreased sharply, even when the laser was less than 1in from the target. When the laser power setting of 30W was used and the external air flow was 100 or 150 feet per minute (fpm) in the same direction as the nozzle flow, high collection efficiencies were obtained for laser/target distances up to 7 to 9in. When the 60 or 100W power settings were used, the laser produced an emissions plume that required an external flow of 200fpm and moving the collector nozzle close to the target to achieve a good collection efficiency. Collection efficiencies obtained with the two nozzles were similar. The authors conclude that the most efficient collection of laser surgery emissions by a smoke evacuator is obtained with the collector nozzle placed as close to the surgical site as possible and with the external air flow directed toward the nozzle. External air flows of 100 to 150fpm can be used with lasers using 30W of power or less. Higher laser powers may require air flows of up to 200fpm.
NIOSH-Author; Aerosol-particles; Biological-material; Emission-sources; Control-equipment; Laser-radiation; Air-flow; Operating-rooms; Medical-equipment;
Author Keywords: gas evacuation; nozzle flow; air flow
Lasers in Surgery and Medicine