CHAPTER XXXI 



CLINICAL APPLICATIONS OF CERTAIN PHYSIOLOGIC 

 METHODS (Cont'd) 



POLYSPHYGMOGRAMS 



In taking polysphygmograms, the following technic is usually followed; 



Venous Pulse Tracings. Direct the observed person to lie down with 

 his head slightly raised by a cushion and bent to the right side. Place 

 the receiver (thistle funnel) over the jugular bulb on the right side of 

 the neck. This lies immediately above the inner end of the clavicle. 

 Bring the style of the recording tambour to write with a minimal 

 amount of friction on the paper or drum. Since a venous pulse tracing 

 can not be interpreted without a simultaneous tracing from an artery, 

 now adjust the button of a receiving tambour over the radial artery and 

 adjust the style of its recording tambour so as to write on the drum in 

 the same perpendicular as the style of the venous tambour. 



Tracings should be taken with the recording surface at a moderate 

 speed. Before disturbing, the relative positions of the writing points, 

 allow them to make vertical marks (with recording surface stationary) 

 at various parts of the tracings. These alignment marks permit of ac- 

 curate comparisons between the curves. Repeat the above, using the 

 carotid instead of the radial. A time tracing ( l / 5 sec.) should always be 

 taken simultaneously. The polysphygmograph is shown in Fig. 95. 



To interpret the venous curve, make a vertical mark on the arterial 

 pulse tracing corresponding to the beginning of the pulse upstroke. If 

 this is done on the radial pulse tracing, measure one-tenth of a second in 

 front of it, and make a vertical mark to allow for the time lost in propa- 

 gation of the pulse from the heart to the radial artery. 



This line 3 (corrected in case of radial pulse) corresponds to the be- 

 ginning of the sphygmic period of ventricular systole i. e., to the open- 

 ing of the semilunar valves. Measure the distance from it to the near- 

 est vertical line that was made to indicate the relative position of the 

 writing points. Then measure off the same distance in the venous trac- 

 ing from the corresponding indicator line. This will fall at the begin- 

 ning of the small wave (c), which is due to the bulging into the auricles 

 of the closed auriculoventricular valves. (Fig. 96.) 



273 



