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. 2009 Apr 9;587(Pt 11):2567–2577. doi: 10.1113/jphysiol.2008.168302

Table 2.

Spectral and transfer function analysis of spontaneous changes in arterial pressure and CBF velocity during phenylephrine infusion

Baseline 0.5 μg 1.0 μg 2.0 μg
MBPVLF (mmHg2) 6.07 ± 1.15 4.32 ± 1.09 3.03 ± 1.15* 3.11 ± 0.75*
MBPLF (mmHg2) 2.15 ± 0.53 1.47 ± 0.38 1.29 ± 0.56 1.93 ± 0.67
MBPHF (mmHg2) 0.31 ± 0.15 0.24 ± 0.07 0.32 ± 0.10 0.52 ± 0.12
CBFVVLF (cm s−1)2) 5.86 ± 1.94 4.53 ± 1.09 3.83 ± 1.43 7.17 ± 3.71
CBFVLF (cm s−1)2) 2.50 ± 0.58 1.84 ± 0.54 1.56 ± 0.52 2.16 ± 0.59
CBFVHF (cm s−1)2) 0.62 ± 0.27 0.47 ± 0.14 0.49 ± 0.11 0.88 ± 0.19
GainVLF (cm s−1 mmHg−1) 0.68 ± 0.06 0.81 ± 0.09 0.67 ± 0.07 0.77 ± 0.09
GainLF (cm s−1 mmHg−1) 1.11 ± 0.06 0.94 ± 0.05* 0.96 ± 0.06* 0.96 ± 0.06*
GainHF (cm s−1 mmHg−1) 1.32 ± 0.07 1.16 ± 0.07 1.04 ± 0.05 1.21 ± 0.09
NGainVLF (units) 0.90 ± 0.08 1.19 ± 0.16 1.04 ± 0.10 1.31 ± 0.16
NGainLF (units) 1.51 ± 0.11 1.38 ± 0.10 1.54 ± 0.11 1.60 ± 0.10
NGainHF (units) 1.79 ± 0.14 1.69 ± 0.13 1.68 ± 0.13 1.95 ± 0.09
PhaseVLF (rad) 1.00 ± 0.12 0.92 ± 0.13 0.72 ± 0.19 0.83 ± 0.11
PhaseLF (rad) 0.66 ± 0.07 0.59 ± 0.07* 0.55 ± 0.07* 0.45 ± 0.09*
PhaseHF (rad) 0.25 ± 0.06 0.13 ± 0.11 0.11 ± 0.08 0.10 ± 0.06
CohereneVLF 0.46 ± 0.05 0.53 ± 0.04 0.38 ± 0.03 0.46 ± 0.04
CoherenceLF 0.66 ± 0.04 0.56 ± 0.05 0.57 ± 0.04 0.66 ± 0.05
CoherenceHF 0.67 ± 0.03 0.62 ± 0.04 0.63 ± 0.05 0.77 ± 0.05

Values are means ±s.e.m., n= 13. MBPVLF, MBPLF, MBPHF, CBFVVLF, CBFVLF and CBFVHF, mean blood pressure (MBP) and cerebral blood flow velocity (CBFV) at the very low, low and high frequencies. GainVLF, GainLF, GainHF, NGainVLF, NGainLF, NGainHF, transfer function gain and normalized gain at the very low, low and high frequencies. PhaseVLF, PhaseLF, PhaseHF, CoherenceVLF, CoherenceLF, and CoherenceHF, phase and coherence at the very low, low and high frequencies.*P < 0.05, compared with baseline. Infusion rate of phenylephrine was 0.5, 1.0 and 2.0 μg kg−1 min−1.