Table 1.

Haemodynamic and respiratory changes during step changes in P_CO2

	Baseline	+ 4%	+ 8%	Hypo 1	Hypo 2
MCAv (cm s−1)	61 ± 15	71 ± 16	107 ± 23*†	52 ± 15*	40 ± 12*†
Pa,CO2 (mmHg)	40 ± 4	44 ± 4	54 ± 4*†	34 ± 3.1*	23.0 ± 4.3*†
PET,CO2 (mmHg)	42 ± 3	47 ± 3	60 ± 3.0*†	36 + 4*	23 + 4.0*†
ePa,CO2 (mmHg)	42 ± 3	46 ± 3*	55 ± 3*†	36 ± 4*	24 ± 4*†
Pjv,CO2 (mmHg)	50 ± 6	52 ± 4	58 ± 5*†	44 ± 4*	41 ± 7*†
TV (l)	0.6 ± 0.3	0.9 ± 0.4*	2 ± 0.3*†	0.9 ± 0.5*	1.2 ± 0.5*
Ventilation (l min−1)	7 ± 2	12 ± 4	33 ± 13*†	9 ± 3	24 ± 9*†
MAP (mmHg)	88 ± 9	89 ± 9	98 ± 11	86 ± 9	80 ± 15
HR (b min−1)	59 ± 10	62 ± 9	74 ± 8	59 ± 7	69 ± 8

Values are mean ±s.d.P_ET,CO2, end-tidal CO₂; eP_a,CO2, regression equation using both end-tidal P_CO2 and tidal volume to estimat eP_a,CO2; P_a,CO2, arterial P_CO2.

^*Different from baseline (P < 0.05);

^†different from + 4 and hypo 1 (P < 0.05).