TABLE 3.

Frequency analysis of mean arterial pressure (MAP), middle cerebral artery velocity (MCAv) and end-tidal CO₂ (etCO₂) in the low-frequency and very low-frequency ranges

Parameter	Low frequency (0.07–0.15 Hz)				Very low frequency (0.04–0.07 Hz)
	0 Hz	0.1 Hz	0.05 Hz	Main effect P-value	0 Hz	0.1 Hz	0.05 Hz	Main effect P-value
MAP power (mmHg2)	4.3 ± 2.7	9.5 ± 7.8*	2.6 ± 1.2†	0.004	3.7 ± 3.3	2.9 ± 2.2	24.3 ± 15.7*†	<0.001
MCAv power [(cm s−1)2]	2.0 ± 2.3	4.6 ± 3.6*	1.2 ± 1.0†	0.003	0.8 ± 0.6	0.8 ± 0.7	2.3 ± 1.6*†	0.002
etCO2 power (mmHg2)	0.09 ± 0.1	0.18 ± 0.1*	0.14 ± 0.2	0.02	0.02 ± 0.02	0.02 ± 0.02	0.06 ± 0.04*†	0.001

Data were analysed with a linear mixed model for repeated measures followed by Tukey’s post hoc tests. Values are reported as means ± SD.

^*P = 0.001–0.07 versus 0 Hz.

^†P = 0.001–0.07 versus 0.1 Hz.