Figure 3
From: Bench-to-bedside review: Ventilatory abnormalities in sepsis
The relationships of diaphragmatic PTI, oxygen consumption, blood flow and arterial blood pressure. (a) The linear relationship between PTI and oxygen consumption. (b) The linear relationship between oxygen consumption and blood flow, which is seen in all muscles. (c) The pressure flow lines for different vascular conductances (1/resistance). The steepest line indicates maximum conductance (minimum resistance) and thus the highest possible flow for any given blood pressure. (d) Maximum PTI is determined by the maximum flow at a given blood pressure. The dotted line in panels a to c shows the maximum flow for that blood pressure that gives the maximum oxygen consumption for that blood pressure, and therefore the maximum sustainable PTI for that blood pressure. BP, blood pressure; PTI, pressure time index; Q-musc, blood flow; VO2-musc, oxygen consumption.