Figure 3. Calculation of cerebrovascular CO₂ reactivity usingP_ET,CO2, P_a,CO2, eP_a,CO2andP_jv,CO2during hypercapnia (A) and hypocapnia (B).

Each faint line represents an individual reactivity. Bold lines represent group average. Note: P_jv,CO2–MCAv reactivity was higher during both hypercapnia (∼97%, A) and hypocapnia (∼24%, B) when compared with P_a,CO2–MCAv reactivity. There seemed to be three visual outliers in both A and B; however, upon closer examination, these data points are within 2 s.d. of the sample mean and therefore not classed as statistical outliers. Further, these data points do not reflect any non-compliance or technical error, and all other data (i.e. heart rate, MCAv, BP, end-tidal CO₂) were normal during each test.