1 5 6 



Scientific Proceedings (39). 



100 (510) 



An experimental study of the resistance to compression of the 



arterial wall. 



By T. C. JANEWAY, M.D., and EDWARDS A. PARK, M.D. 



[From the Department of Practice of Medicine, College of Physicians 

 and Surgeons, Columbia University.] 



The object of this study was to determine whether the resist- 

 ance to compression of the arterial wall introduces an error of 

 any importance in the clinical measurement of systolic blood pres- 

 sure by methods employing circular compression of the arm. 



No previous studies are free from serious criticism on the 

 ground of inaccuracy of the methods employed. Some direct on 

 post-mortem vessels (v. Basch, Martin, Herringham and Wo- 

 mack), and some indirect (Oliver, Hill, Williamson, Russell). In 

 consequence of the discordant results, opinion has been divided. 

 Some hold the resistance to compression of the arterial wall to 

 be negligible; others that it might be extreme. The present study 

 has been carried on by a method giving graphic records of the 

 pressure within the artery, the pressure in the external compressing 

 medium, and of the changes in the outflow from the artery by a 

 Hiirthle membrane manometer. Ringer's solution was used in all 

 the experiments. The point of first collapse of the artery, of 

 complete obliteration of its lumen, and of resumption of the flow 

 on lowering the external pressure after obliteration were recorded 

 in each experiment. The latter proved by far the most constant 

 index and most analogous to the ordinary criterion of the return 

 of the pulse in clinical work. 



The post-mortem vessels examined gave the following results: 



Ten carolids from infants. 



Readings at 30, 100, and 150 millimeters internal pressure. 

 Difference of pressure at which flow ceased : 



Maximum 



Average 



Minimum 



= 8 mm. Hg. 

 - 3.9 mm. Hg. 

 = I mm. Hg. 



