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CrossTalk opposing view: Guyton's venous return curves should not be taught
Author(s) -
Beard Daniel A.,
Feigl Eric O.
Publication year - 2013
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2013.260034
Subject(s) - mean circulatory filling pressure , venous return curve , cardiac output , medicine , starling , cardiology , ventricle , central venous pressure , blood pressure , heart rate , hemodynamics
The thesis of this essay is that Guyton’s model of the systemic circulation has been so misinterpreted by Guyton and others that it generates more confusion than insight. Because of the capacitance of arteries and veins, blood pressure will attain a finite value if blood flow is quickly stopped without a change in vascular tone. This static pressure is called the ‘mean systemic pressure’ PMS. Guyton devised an experimental preparation in open chest dogs where an external artificial pump drew blood from the right atrium and delivered it to the pulmonary artery. The output flow rate of the pump was manually adjusted by raising and lowering a collapsible tube (Starling resistor) at the inlet (right atrial) side of the pump. In this way the steady state cardiac output flow of the left ventricle was set as the independent experimental variable. In other words, the artificial pump opened the circuit of the circulation and haemodynamically isolated the right atrium from the heart so that the systemic circulation could be studied in quasi-isolation. As will be explained, the confusion over Guyton’s results and