The Japanese journal of physiology
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The transvascular fluid shift after blood volume modification was analyzed by means of continuous blood volume determination and stimulation analysis. On splenectomized dogs, 15% of the circulating blood was withdrawn and retransfused, while the circulating blood volume, hematocrit and colloid osmotic pressure were continuously monitored. Based on the results, the transvascular fluid shift was stimulated by a two-compartment model. ⋯ The compliance of the vascular space, 4.62 +/- 0.82 ml/mmHg . kg of body weight, was almost identical with that of the interstitial fluid space, 4.75 +/- 1.52 ml/mmHg . kg of body weight. The whole body capillary filtration coefficient was 0.74 +/- 0.39 ml/min . mmHg . kg of body weight, which is within the range of the reported values of the capillary filtration coefficient for muscle and intestine. It is suggested that the rapid transvascular fluid shift after blood volume modification is provided with the fact that the compliances of intravascular and interstitial fluid spaces are almost identical.
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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. ⋯ 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.