Improved techniques for cardiovascular monitoring in rats as applied during endotoxemia

We describe a new combination of techniques for measurements of systemic blood pressure, central venous pressure, pulmonary arterial (PA) pressure, PA wedge pressure, and cardiac output in the rat. Application of the method to the conscious rat in a septic shock (Escherichia coli endotoxin iv injection) model demonstrated a response pattern of decreased cardiac output and stroke volume, increased total peripheral vascular resistance and heart rate, and transiently decreased systemic arterial pressure. In the pulmonary circulation, a very brief hypertension and a sustained increase in pulmonary vascular resistance were observed, but changes in PA wedge pressure were small. The soft PA catheter (0.3 mm ID, 0.6 mm OD) had no undue effects on cardiovascular function. We suggest that this combined technique could be useful for many cardiovascular studies in the rat, not only as related to shock research.