Doppler and Volumetric Echocardiographic Methods for Cardiac Output Measurement in Standing Adult Horses
Article first published online: 16 JAN 2013
Copyright © 2013 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 27, Issue 2, pages 324–330, March/April 2013
How to Cite
McConachie, E., Barton, M.H., Rapoport, G. and Giguère, S. (2013), Doppler and Volumetric Echocardiographic Methods for Cardiac Output Measurement in Standing Adult Horses. Journal of Veterinary Internal Medicine, 27: 324–330. doi: 10.1111/jvim.12034
- Issue published online: 15 MAR 2013
- Article first published online: 16 JAN 2013
- Manuscript Accepted: 27 NOV 2012
- Manuscript Revised: 23 AUG 2012
- Manuscript Received: 13 MAR 2012
- University of Georgia's Love
- 4-chamber area-length;
- Critical care;
- Hemodynamic monitoring
Cardiac output (CO) is not routinely measured in critically ill adult horses because of invasiveness of currently validated methods. Noninvasive CO monitoring would complement clinical assessment of hemodynamic status in adult horses.
Volumetric methods for measuring CO will have better agreement with lithium dilution than Doppler-based methods.
Eight healthy adult horses.
Prospective study. CO was manipulated with continuous rate infusions of dobutamine and romifidine to achieve high and low CO states, respectively. At each level, CO was measured by lithium dilution and various echocardiographic methods. Images stored as video loops were reviewed by an individual blinded to the lithium dilution results.
Lithium dilution determinations of CO ranged between 16.6 and 63.0 L/min. There was a significant effect of method of CO measurement (P < .001), but no significant effect of CO level (P = .089) or interaction between level and method (P = .607) on the absolute value of the bias. The absolute values of the bias of the right ventricular outflow tract (RVOT) Doppler, Simpson, 4-chamber area-length, and bullet methods [5.5, 6.1, 6.5, 8.8 L/min, respectively] were significantly lower than that of the left ventricular outflow tract (LVOT) Doppler or cubic methods [14.8, 24.3 L/min, respectively].
Conclusions and Clinical Importance
The 4-chamber area-length, Simpson, bullet, and RVOT Doppler provided better agreement with lithium dilution than the other methods evaluated. These methods warrant further investigation for use in critically ill adult horses.