title: Maximum capacity of ventilation and efficiency of gas exchange during liquid breathing in guinea pigs.
abstract: Mechanical characteristics of liquid breathing were studied in isolated lungs of guinea pigs filled with fluorocarbons FC-75 and 77. It was found that compliance increased to 2-2.5 times, resistance increased to 20 times, and maximum expiratory flow decreased to 1/20-1/25 times the corresponding values observed in air-filled lungs. The maximum volume of ventilation during liquid breathing was then predicted to be 50 ml/min from parameters mentioned above, and about 80% of such ventilation was actually observed in anesthetized animals. Measurements on O2-uptake and CO2-output as well as gas analysis of arterial blood showed that the ventilation volume was insufficient to maintain the normal gas exchange in the animal unless body temperature was lowered. An increase in physiological dead space observed during liquid breathing suggested that slow diffusion rate of gases through the liquid was responsible for the deficiency of the gas exchange.
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D005260:Female; D005466:Fluorocarbons; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008168:Lung / Q000502:physiology*; D008170:Lung Compliance; D008176:Lung Volume Measurements; D008297:Male; D010101:Oxygen Consumption; D012119:Respiration; D012126:Respiratory Dead Space; D012996:Solutions; D013990:Tidal Volume
chemical_list: D005466:Fluorocarbons; D012996:Solutions; D002245:Carbon Dioxide