Hemodynamic consequences of halothane anesthesia during chronic anemia

The hemodynamic effects of halothane anesthesia in chronically anemic mongrel dogs were evaluated. Control and anemic animals (13.7 +/- 0.4 g/dl hemoglobin mean +/- SE vs. 3.4 +/- 0.3 g/dl) were exposed to 0.75, 1.5, and 2.25% inspired halothane and changes in cardiac output (CO), heart rate (HR), dp/dt, heart work, heart efficiency, myocardial oxygen consumption (MVO2), mean arterial blood pressure (MABP), central venous pressure (CVP), left ventricular end-diastolic pressure (LVDP), left coronary blood flow (CBF), systemic vascular resistance (SVR), and myocardial lactate metabolism were measured and compared. Anemic dogs showed a significantly lower SVR at each halothane dose when compared with controls. In addition, SVR progressively decreased with increasing halothane in anemic dogs, while SVR remained unchanged in controls. CO, CBF, MVO2, and heart work all were significantly greater in anemic canines compared with controls with each halothane concentration. Heart efficiency, dp/dt, HR, and MABP were not significantly different in anemic and control dogs. Neither control nor anemic dogs demonstrated myocardial hypoxia as evidenced by a lack of myocardial lactate production. The results from this study suggest that anemic animals appear to tolerate large concentrations of halothane.