Determination of cardiac output and other reference physiology parameters in lightly anesthetized dogs

1. 1. Cardiac output; arterial, pulmonary artery, central venous and pulmonary wedge pressures; heart rate, hematocrit, and plasma sodium and potassium; arterial and mixed venous blood gases; and respiratory rates were measured in 45 mixed sex, non-pregnant, clinically normal mongrel dogs of 8–30 kilograms body weight following light anesthesia with halothane/50% N20-02. 2. 2. Arithmetic means and standard deviations were calculated to develop tables of reference values. 3. 3. Mean measured cardiac outputs were found to be 31–59% higher in these dogs than the values indicated by published standards; cardiac indices were 30–44% higher; heart rates were 16–30% lower; calculated stroke volumes were 60–112% greater; and total peripheral resistances were 35–57% less than the standard published values. 4. 4. All other measured or calculated parameters fell within previously published canine or human reference limits.