Effect of injections of hypertonic solutions on blood flow through the femoral artery of the dog

Abstract

Blood flow through the femoral artery was measured in 10 dogs; a bubble flowmeter was used in 5 and, in the other 5, an ultrasonic flowmeter was used. Rapid injections of 2 ml of 10–20% solution of NaCl caused a definite but transient reduction in flow, followed by a prolonged twofold to threefold increase. Similar effects were noted with other Na salts and also with 25–50% dextrose solution. The use of 25 and 50% solutions of urea caused only a prolonged increase in flow. Isotonic NaCl solution had little or no effect. Continuous infusions at 2.3 ml/min. of 10 and 20% solution of NaCl and 50% dextrose and urea solutions caused only doubled to tripled increase in flow which continued throughout infusion. The initial reduction in flow cannot be explained by reduction in perfusion pressure and may result from reversible hemagglutination in small vessels. The increase in flow is due to vasodilatation locally mediated, since it could not be accounted for by changes in perfusion pressure and was unchanged after denervation of the leg. The mechanism of the dilatation is uncertain, but since it occurs with salt-free hypertonic solutions it is not specific for sodium-containing salts.