Fig. 4.

This histogram of the change in mean aortic pressure was calculated by subtracting the mean aortic pressure 36-40 s before the calcium bolus from the mean aortic pressure 36-40 s after the calcium bolus. While most of these interventions are associated with a positive change in mean aortic pressure, in four experiments, the mean aortic pressure decreased. In these experiments, the animal was decompensating rapidly, and the continuing drop in blood pressure was larger than the benefit of the calcium bolus