Use of Dopamine, Dobutamine, and Detomidine Plus Butorphanol to Alter Cardiac Output in a Study Comparing the Measurement Methods of M-Mode Echocardiography and Thermodilution in Anesthetized Horses

Objectives – 1. To determine the suitability of a pharmacological protocol for inducing a range of cardiac outputs in anesthetized horses. 2. To determine whether such a protocol could be used in a study comparing the methods of M-mode echocardiography and thermodilution for determination of cardiac output. Animals – Five horses with no evidence of cardiovascular or other systemic disease. Methods – Determinations of cardiac output by M-mode echocardiography were compared with simultaneous determinations by thermodilution in anesthetized horses. Cardiac output (CO) was modified by the administration of dopamine (4 ug/kg/min), dobutamine (4 ug/kg/min), and detomidine (10 ug/kg) plus