Why does Blood pressure important in low TPR?

This is the example: we have vasodilation (decrease TPR) in septic shock, the MAP will decrease despite of CO will increase (MAP=TPR*CO). So, we have high perfusion of tissues, because of arteriolodilation. So what is the problem? Why if we have decreased pressure (due to decreased TPR) it will cause problems like: syncope, low perfusion of tissues and etc? I really want to UNDERSTAND the importance of blood pressure in this situation (in the cases of low TPR=>high CO, low MAP). This my... Why does Blood pressure important in low TPR?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums