Real-time measurement and control of waste anesthetic gases during veterinary surgeries.
Am Ind Hyg Assoc J 1990 Dec; 51(12):640-645
A survey of waste anesthetic gas exposures during veterinary surgeries was conducted. Waste anesthetic gas concentrations were monitored during surgical procedures at five veterinary clinics in the Morgantown, West Virginia area using a modified Miran 1A infrared spectrophotometer. Work practices were observed. A technique for controlling anesthetic gas exposures was proposed. Three clinics used methoxyflurane (76380) and two used halothane (151677). None of the clinics used a gas scavenging system. One hour time weighted average exposures of methoxyflurane and halothane ranged from 0.5 to 44.5 and 0.2 to 105.4 parts per million (ppm), respectively. The NIOSH recommended standard for methoxyflurane, halothane, and other halogenated agents is 2ppm. The major causes of the methoxyflurane and halothane exposures were: leaking or unsealed endotube cuffs that produced a free flow of gas when disconnecting and reconnecting animals from anesthesia carts; improper purging of anesthetic gases from animals at the end of operations; and unscavenged carts. A charcoal adsorption system consisting of 2.5 kilograms of activated charcoal housed in a 101.6 millimeter (mm) diameter 406.4mm length of polyvinyl-chloride pipe attached to the anesthesia machine reduced the concentrations of methoxyflurane and halothane by at least 95%. The authors note that the newly developed scavenging system can be fabricated out of materials and hardware available at local retail stores and costs less than 45 dollars.
NIOSH-Author; Anesthetics; Industrial-hygiene; Work-practices; Control-methods; Indoor-air-pollution; Halogenated-compounds; Veterinary-medicine; Indoor-environmental-quality
American Industrial Hygiene Association Journal