CHAPTER 3! 



Methods of measuring blood flow 



KURT KRAMER 



WILHELM LOCHNER 



E. WETTERER 



Physiologisches Inslitut der Universitdt, Gbttingen, Germany 

 Physiologisches Institut der Medizinischen Akademie, Diisseldorf, Germany 

 Physiologisches Inslitut der Universitdt Miinchen, Miinchen, Germany 



CHAPTER CONTENTS 



Varied Methods and Instruments for Flow Measurement 

 Admixing Methods for Measurement of Regional Blood Flow 

 Flowmeters: Their Theory, Construction, and Operation 



Perhaps no other field of physiological methodology encom- 

 passes such a variety of physical and chemical principles as 

 that of flow measurement. Principles of measurement may be 

 and have been developed from almost every topic in physics 

 textbooks: mechanics {solid, liquid, and gas), sound, elec- 

 tricity, magnetism, optics, thermodynamics, and atomic 

 physics. For this reason we have divided the duties of this 

 section and each author has taken the field of his choice; or, 

 more correctly, two authors have chosen and one (K. K.), 

 like Cinderella, has made do with the remainder. 



We have set ourselves the task first to review these various 

 principles, or at least to sketch their historical development, 



and second to acquaint the reader with the manner in which 

 each method fits the special purposes of the investigator. 



We have attempted to give a more detailed description of 

 modern techniques or older ones which are still in use today; 

 in this we have tried to present not so much an account of 

 technical details of a piece of apparatus as special suggestions 

 which will facilitate its use, permit judgment of its reliability, 

 and guard against sources of error. What we take for reality 

 sometimes changes so that it is often difficult to distinguish 

 that which is true only for the moment from that which will 

 endure. 



If older methods no longer in use today are mentioned, it 

 is to point out particular disadvantages which caused them 

 to be abandoned. In this way we hope to guide the young 

 traveler who might otherwise take these fruitless paths again. 



K. KRAMER 

 W. LOCHNER 

 E. WETTERER 



I. Varied methods and instruments for flow measurement 



KURT KRAMER 



CONTENTS 



Outflow Measurements 



Venous Outflow Collection 

 Drop Recording 



Methods Based on Ludwig's Principle 



Bubble Flowmeter 

 Venous-Occlusion Methods 



Pulse Plethysmography 



Photoelectric Plethysmography 

 Thermal Methods 



Thermostromuhr 



Skin Blood Flow Measurement Based on Thermal Con- 

 ductance Measurement 



Flowmeters Based on the Measurement of Thermal Con- 

 ductivity 



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