. 2019 Dec 16;162(2):345–356. doi: 10.1007/s00701-019-04118-6

Table 1.

Mean values and SD of the studied parameters at the baseline and during hypocapnia. When the changes between baseline and hypocapnia are significant, the direction of the change is highlighted. p values of univariate analysis are quoted uncorrected for multiple comparison

Variable			Baseline		Hypocapnia		Change	p value
Variable			Mean	SD	Mean	SD	Change	p value
Frequency domain	Power of sw (mmHg²)	ICP	1.04	1.82	0.27	0.49	↘	0.006*
		ABP	2.95	4.14	1.90	1.40		0.177
		FVl	16.02	20.48	10.90	13.66	↘	0.049*
		FVr	16.88	21.69	9.48	11.67	↘	0.005*
	Centroid of sw (Hz)	ICP	0.020	0.006	0.023	0.005	↗	< 0.001*
		ABP	0.016	0.005	0.020	0.006	↗	< 0.001*
		FVl	0.023	0.006	0.027	0.004	↗	< 0.001*
		FVr	0.022	0.006	0.026	0.005	↗	< 0.001*
Time domain, sw	Entropy of sw	ICP	0.50	0.11	0.56	0.06	↗	< 0.001*
		ABP	0.44	0.11	0.51	0.10	↗	< 0.001*
		FVl	0.55	0.07	0.58	0.05	↗	< 0.001*
		FVr	0.54	0.09	0.58	0.07	↗	< 0.001*
Time domain, time series	Time series (mmHg)	ICP	16.65	6.70	13.03	6.35	↘	< 0.001*
		ABP	96.45	8.98	98.83	11.65		0.100
		FVl	77.67	35.65	65.57	29.72	↘	< 0.001*
		FVr	78.14	26.82	61.65	17.50	↘	< 0.001*
	Coefficient of variation	ICP	0.09	0.05	0.10	0.08		0.206
		ABP	0.04	0.02	0.04	0.02		0.936
		FVl	0.07	0.03	0.08	0.04		0.071
		FVr	0.07	0.03	0.08	0.04		0.249
	Variance	ICP	2.23	2.16	1.39	1.39	↘	0.006*
		ABP	14.94	13.29	17.10	32.21		0.700
		FVl	37.10	36.29	39.37	71.75		0.825
		FVr	40.89	41.65	37.83	72.34		0.869
Time domain, derivate indexes	Coherence ICP-FVl		0.78	0.19	0.78	0.19		0.951
	Coherence ICP-FVr		0.76	0.21	0.76	0.19		0.401
	Ci_l (cm³/mmHg)		2.15	1.41	3.08	2.38	↗	0.006*
	Ci_r (cm³/mmHg)		2.36	1.63	3.07	2.69	↗	0.008*
	RAP		0.51	0.34	0.41	0.34	↘	0.026*

sw slow waves, ICP intracranial pressure, ABP arterial blood pressure, FVl flow velocity left, FVr flow velocity right, Ci_l compliance of cerebrospinal space left, Ci_r compliance of cerebrospinal fluid right, RAP compensatory reserve index

* denotes statistically significant finding