Table 3.

Partial pressures of end-tidal CO₂ and middle cerebral artery flow velocities during CO₂ reactivity

	Study group
	Patients (n = 15 [Af] and 14 [Un])*			Controls (n = 14)
	Baseline	Hypercapnia	Hypocapnia	Baseline	Hypercapnia	Hypocapnia
PETCO2, mmHg	31.7 ± 4.4	37.0 ± 5.1†	26.2 ± 4.0†	30.1 ± 5.1	35.2 ± 5.4†	25.1 ± 4.6†
MCAv, cm sec−1	Af 42.8 ± 11.9 Un 40.7 ± 13.2	Af 54.9 ± 17.1† Un 51.9 ± 16.1†	Af 34.7 ± 6.4† Un 33.1 ± 7.0†	38.1 ± 9.2	46.1 ± 11.5†	32.0 ± 7.3†

Values are mean ± SD. Baseline refers to the 30 sec immediately preceding the hypercapnia procedure. Hypercapnia and hypocapnia refer to the maximum and minimum P_ETCO₂ respectivley, during CO₂ reactivity testing. MCAv data is presented in raw units for ease of interpretation, but was normalised for CO₂ reactivity analysis. Af, affected hemisphere; Un, unaffected hemisphere; P_ETCO₂, partial pressure of end-tidal CO₂; MCAv, middle cerebral artery flow velocity.

^*For hypocapnia response. For hypercapnia, n = 14 affected hemisphere and 13 unaffected hemisphere of patients.

^†P < 0.01 versus baseline.