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. Author manuscript; available in PMC: 2009 Sep 1.
Published in final edited form as: Stroke. 2008 Jul 31;39(9):2531–2537. doi: 10.1161/STROKEAHA.108.514877

Figure 1.

Figure 1

Determining the LLA for each subject. A, Construction of an autoregulation curve for a piglet with naïve ICP. ABP (mm Hg), ICP (mm Hg), LD flux (LDOPPLER, AU), and cerebral oximetry (CEREBROX, % saturation) were recorded while a balloon catheter in the inferior vena cava was gradually inflated over 2 to 4 hours. LD measurements of flux were then plotted as a function of CPP. This plot is demarcated into 2 sets of data having best-fit lines with the lowest combined residual squared error. Solving for the intersection of the 2 lines yields the LLA. Notice the spontaneous slow increase in ICP with decreasing ABP and the increase in frequency and amplitude of spontaneous B waves, also with decreasing ABP. B, Example for a piglet with an ICP of 20 mm Hg. Before a reduction in ABP, the ICP was increased to 20 mm Hg by a steady-state infusion of artificial cerebrospinal fluid, which was maintained throughout the experiment.