Fig. 1. The %CBFCPP60area under the autoregulatory curve, and pattern are used to characterize the vasodilatory response to hypotension. This figure shows three typical autoregulatory curves, plotted as linear segments (solid line) connecting the five pairs of CPP and %CBF: panels A, B, and C show none, classic, and peak patterns, respectively. The line from zero %CBF at 30 mmHg CPP and 100 %CBF at 90 mmHg CPP (dashed line) was used as the baseline for the calculation of autoregulatory area. The solid vertical line shows the magnitude of the curve at 60 mmHg CPP, %CBFCPP60. The autoregulatory area and %CBFCPP60are 982, 2301, 3500 mmHg-%CBF and 64, 97, 128 %CBF, respectively, for the none (A ), classic (B ), and peak (C ) curves. The lower limits were 56 and 60 mmHg CPP for the classic (B ) and peak (C ) curves, respectively.