title: Liquid breathing trials and animal studies with a demand-regulated liquid breathing system.
abstract: Experimental results of in vivo animal tests conducted on a demand-regulated liquid breathing system are presented. When a liquid replaces gas as the medium in which oxygen and carbon dioxide are transported, several problems not typical in gas respiration occur. The increased mass and viscosity of a liquid as compared with a gas necessitate some means of mechanical assistance. The lower diffusion rates of gases in liquids as compared with gas rates places several constraints on the design of a mechanically assisted liquid breathing system. The liquid breathing system reported in this study has been designed to be demand-regulated, i.e., the animal has control over cycling the pumps which mechanically assist the circulation of an oxygenated liquid to and from the lungs. This system consists of a gas-operated diaphragm pump, demand controller, liquid regenerator with heater and gas scrubber, and ancillary equipment. A demand controller is described which obtains a control signal from an esophageal balloon catheter in the animal and governs operation of the pneumatically driven diaphragm pump.
mesh_terms: D000403:Airway Resistance; D000818:Animals; D001698:Biomedical Engineering; D002245:Carbon Dioxide / Q000097:blood; D004285:Dogs; D008168:Lung / Q000502:physiology*; D008170:Lung Compliance; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D012119:Respiration; D013147:Spirometry; D012122:Ventilators, Mechanical / Q000295:instrumentation*; D014797:Vital Capacity
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen