Cardiorespiratory effects of Pseudomonas and E. coli endotoxins in the awake dog

A comparison of the cardiovascular and respiratory effects of Pseudomonas aeruginosa and Escherichia coli endotoxins was investigated in the unanesthetized dog. Animals were anesthetized with halothane for placement of cardiovascular catheters and then allowed to awaken prior to collection of control data and experimentation. One group of 12 animals was given E. coli endotoxin (5 mg/kg), another group of 13 received Pseudomonas endotoxin (8 mg/kg). Variables were collected for 6 h after endotoxin injection. A third group of 13 animals serving as sham animals received no endotoxin. When major cardiovascular variables, such as arterial blood pressure, cardiac output, right atrial pressure, and left ventricular pressure and dP/dt were monitored, it was seen that the basic patterns of response to endotoxins were quite similar, with differences between groups being primarily quantitative. Analysis of respiratory data showed that animals receiving Pseudomonas developed an earlier respiratory response. Nevertheless, blood gas data were similar in the two groups.