A mask for delivery of inhalation gases to small laboratory animals

A mask was developed for the administration of volatile anesthetics and other gases to small, spontaneously breathing laboratory animals. A vacuum-powered venting system surrounding the inspiratory gas supply prevented potentially hazardous gases from escaping into the environment. This system was used to deliver nitrous oxide, halothane, and methoxyflurane to rats, gerbils, and newborn dogs. It was used to vary the oxygen and carbon dioxide concentrations inspired by spontaneously breathing animals undergoing physiological experiments.