Effect of Venous Pressure on Volume Pulsation

Abstract

In a previous study it was noted that, with ligation of the main venous outlet from the lower extremity of the dog, a marked reduction in peripheral pulse volume occurred. 1 The present observations were made to throw some light on the mechanism of these changes.

In 14 dogs the volume of pulsations in the hind foot was determined by adapting a specially constructed cellulose-acetate cup to the sensitive plethysmograph of Turner. 2 All observations were conducted under ether anesthesia and the operative procedure, consisting of isolation and ligation with silk of the femoral vein at the level of Poupart's ligament, was performed aseptically. Direct venous pressure determinations 3 were made in the saphenous vein at heart level before and after the ligation during the continuous determination of pulse volume. All observations were conducted under controlled atmospheric conditions, temperature 75 °F and humidity 50%.

Observations were made on 2 groups of dogs: (1) 6 animals with intact sympathetic innervation, and (2)8 animals on which resection of the ipsolateral lumbar sympathetic ganglia and intervening chain had been performed 24 hours previously.

Results. The results are graphically represented in Fig. 1. It may be observed that the rises in venous pressure in the femoral vein following ligation were 13.9 and 10.5 times the normal value in the non-sympathectomized and sympathectomized animals, respectively. The decreases in volume of pulsations following the ligations were 51.5% and 58.2%, respectively. The results obtained in each dog were essentially the same as the mean values, except in degree. It may also be observed that although the reactions in the sympathectomized and non-sympathectomized animals were essentially the same, the pulse volumes both before and after ligation were slightly lower in the sympathectomized than in the non-sympathectomized dogs, and that the corresponding venous pressures were slightly higher in the former.