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Cardiovascular effects of dopexamine HCI in conscious and halothane‐anaesthetised horses
Author(s) -
III W. W. MUIR
Publication year - 1992
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1992.tb04767.x
Subject(s) - halothane , medicine , anesthesia , dobutamine , cardiac output , heart rate , hemodynamics , tachycardia , blood pressure , vascular resistance
Summary The cardiovascular effects of serial increasing infusions of dopexamine HCI were investigated in six conscious (1, 2, 4, 6, 10 μg/kg bodyweight [bwt]/min) and eight (0.5, 1, 5, 10, 20 μg/kg bwt/min) halothane‐anaesthetised horses. Dopexamine produced dose‐dependent increases in heart rate, +dP/dt max' ‐dP/dt max and cardiac output, and a decrease in systemic vascular resistance in conscious and halothane‐anaesthetised horses. Mean arterial blood pressure did not change in conscious horses but increased to a maximum value at 10 μg/kg bwt/min in halothane‐anaesthetised horses. Thereafter, median artery blood flow decreased. Ventricular arrhythmias occurred in two conscious horses during the infusion of 10 μg/kg bwt/min dopexamine HCI. No cardiac arrhythmias other than sinus tachycardia were observed in halothane‐anaesthetised horses. The administration of propanolol eliminated the haemodynamic response to the infusion of 5 and 10 μg/kg bwt/min dopexamine HCI in halothane‐anaesthetised horses. The haemodynamic effects of dopexamine HCI offer specific advantages over dopamine and dobutamine for the treatment of low cardiac output states in horses.