. 2012 Jul 5;4:8. doi: 10.3389/fnene.2012.00008

Table 1.

Carbon dioxide reactivity.

	PaCO₂ mmHg			Relative PaCO₂ mmHgv			CBF mL/min 100 g			CBF fractional
	H	C	E	FH/C	FC/C	FE/C	H	C	E	H/C	C/C	E/C
Ramsay et al. (1993)
Gray matter	24	38	55	24.9	39.5	57.2	45	73	115	0.62	1.00	1.58
	23	38	55	23.9	39.5	57.2	37	50	105	0.74	1.00	2.10
	24	41	53	23.1	39.5	51.1	32	47	108	0.68	1.00	2.30
	20	40	55	19.8	39.5	54.3	43	68	118	0.63	1.00	1.74
	20	42	57	18.8	39.5	53.6	30	51	75	0.59	1.00	1.47
	20	38	55	20.8	39.5	57.2	49	52	104	0.94	1.00	2.00
White matter	24	38	55	24.9	39.5	57.2	18	16	28	1.13	1.00	1.75
	23	38	55	23.9	39.5	57.2	12	20	35	0.60	1.00	1.75
	24	41	53	23.1	39.5	51.1	15	25	39	0.60	1.00	1.56
	20	40	55	19.8	39.5	54.3	10	21	39	0.48	1.00	1.86
	20	42	57	18.8	39.5	53.6	10	22	32	0.45	1.00	1.45
	20	38	55	20.8	39.5	57.2	15	20	32	0.75	1.00	1.60
Mean	21.8	39.5	55	21.8	F = 39.5	55.0
Kety and Schmidt (1946)
Active- hyper- ventilation	31	52		23.5	39.5		44	59		0.75	1.00
	28	55		20.1	39.5		51	87		0.59	1.00
	29	43		26.6	39.5		40	70		0.57	1.00
	32	41		30.8	39.5		48	56		0.86	1.00
	24	44		21.5	39.5		40	69		0.58	1.00
	25	43		23.0	39.5		52	79		0.66	1.00
Passive- hyper- ventilation	22	38		22.9	39.5		40	59		0.68	1.00
	23	42		21.6	39.5		44	62		0.71	1.00
	30	46		25.8	39.5		47	72		0.65	1.00
	27	45		23.7	39.5		40	81		0.49	1.00
	22	45		19.3	39.5		36	55		0.65	1.00
Mean	26.6	44.9
Kety and Schmidt (1948)
5% CO₂		42	50		39.5	47.0		48	65		1.00	1.35
		42	47		39.5	44.2		50	67		1.00	1.34
		41	48		39.5	46.2		46	75		1.00	1.63
		48	54		39.5	44.4		63	90		1.00	1.43
		41	46		39.5	44.3		56	80		1.00	1.43
		42	53		39.5	49.8		63	141		1.00	2.24
7% CO₂		45	60		39.5	52.7		53	135		1.00	2.55
		45	58		39.5	50.9		45	90		1.00	2.00
Mean		43.3	52.0
Grand mean ([kPa])				22.7 (3.03)	39.5 (5.27)	51.5 (6.87)				0.67	1.00	1.71

The arterial PaCO₂ and CBF values from three human studies (Kety and Schmidt, 1946, 1948; Ramsay et al., 1993) are shown. The PaCO₂ values for hyperventilation (H) control situation with normocapnia (C) and an experimental period (E) with special gas mixture enriched with 5–7% CO₂ are shown in absolute values and relative (FH/C, FC/C, and FE/C) values normalized to standard average of F=39.5 mm Hg, taken from Ramsay et al. (1993). The CBF values for each situation (H, C, E) are shown in mL/100 g/min and as fraction of normocapnic flow (H/C, C/C, E/C).