Gas Scavenging during Bronchoscopy under General Anesthesia

Prevention of exposure of the endoscopist to high levels of anesthetic gases during bronchoscopy was attempted experimentally in dogs by a scavenging system. Results were compared with exposure during the conventional technique of anesthetic gas administration for clinical bronchoscopy using the rigid open ventilating bronchoscope. The scavenging system consisted of a vacuum pump applied to the open ventilating rigid bronchoscope sidearm connection during intratracheal administration of nitrous oxide, oxygen, and halothane gas mixture. Gas samples were taken from the trachea, the proximal end of the bronchoscope, and the endoscopist's breathing zone, and analyzed by gas chromatography. Findings indicate that halothane anesthesia for bronchoscopy administered by conventional techniques is a source of air pollution in the operating room and exposes the endoscopist to subanesthetic levels of halothane that may affect psychomotor functioning. The use of the gas scavenging system lowered the concentrations of halothane and nitrous oxide at the endoscopist's breathing zone to a level at which inhalation for short periods has no clinical effects, while the concentrations of the anesthetics and oxygen in the trachea were maintained at a satisfactory level.