Comparison of conductance to volume equations: the gain coefficient alpha.
The conductance catheter technique is used to measure real-time pressure and volume data in a beating heart. There are three competing equations for transforming the raw conductance signal into volume: (1) Baan's equation, (2) The cuvette equation (i.e. Relative Volume Units), and (3) Wei's equation. This paper explores the accuracy of these three equations compared to ultrasound echo in mice, and discusses the reason for discrepancy regarding both Baan's equation and the cuvette equation. We conclude that Wei's equation is the most accurate, because its nonlinear mapping yields volumes in the range of physiologic norms.
Porterfield
John E
JE
Electrical and Computer Engineering Department, The University of Texas, Austin, TX 78712, USA. john.porterfield@mail.utexas.edu
Pearce
John A
JA
D000465:Algorithms; D000818:Animals; D001011:Aorta / Q000000981:diagnostic imaging / Q000473:pathology; D001698:Biomedical Engineering / Q000379:methods; D001794:Blood Pressure; D003627:Data Interpretation, Statistical; D004452:Echocardiography / Q000379:methods*; D020342:Finite Element Analysis; D006329:Heart Conduction System; D006339:Heart Rate; D051379:Mice; D008810:Mice, Inbred C57BL; D008955:Models, Cardiovascular; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors