Table 4.

Associations of a priori selected HD treatment–related factors with CBF

VariablepCO2 (kPa)pH (per 0.1 change)Temperature (°C)UF Volume (L)
Estimated effect on CBF (ml/100 g per min)Estimated effect on CBF
(ml/100 g per min)Estimated effect on CBF (ml/100 g per min)Estimated effect on CBF (ml/100 g per min)
pHpH*T2
Interaction with scan-orderaNoYesYesNoNo
Region
 Global2.2 (−1.1 to 5.4)1.9 (−4.5 to 8.1)−5.7 (−10.7 to −5.7)0.04 (−2.9 to 3.1)−3.7 (−6.0 to −1.3)b
 Regional
  Frontal lobe3.5 (1.1 to 5.7)b7.0 (1.7 to 11.0)b−9.7 (−12.7 to −5.3)c−2.1 (−3.3 to −0.7)b−4.6 (−6.9 to -2.1)b
  Parietal lobe4.2 (2.0 to 6.2)c2.7 (−2.0 to 7.0)−7.1 (−10.0 to −3.8)c−2.5 (−3.9 to −1.0)b−4.7 (−7.5 to −1.6)b
 Temporal lobe3.1 (0.9 to 5.3)b1.5 (−2.8 to 5.7)−5.8 (−8.8 to −2.8)c−1.7 (−2.8 to −0.6)b−4.6 (−6.9 to −2.2)b
 Occipital lobe4.4 (0.9 to 7.7)d−1.6 (−8.4 to 4.5)−6.6 (−11.6 to −1.6)d−3.0 (−4.9 to −0.9)b−5.0 (−7.8 to −1.9)b
  Cerebellum3.9 (0.5 to 7.2)d2.5 (−3.9 to 8.6)−8.4 (−13.4 to −3.7)b−2.5 (−3.6 to −1.3)c−4.7 (−8.2 to −1.0)d
  Thalamus5.2 (0.9 to 9.3)d1.1 (−7.4 to 9.3)−10.0 (−14.4 to −1.5)d−1.0 (−4.8 to 3.1)−5.8 (−10.0 to −1.5)d
  • Associations were studied using linear mixed effects models including a random intercept and slope. The estimated effect (95% CI) of the individual characteristics on CBF is presented. Of the a priori selected factors, the analysis of MAP and CBF was limited by insufficient power due to missing values and patient variation, and considered inconclusive. Hematocrit was associated with CBF only in one VOI.

  • a No interaction with scan-order means that the effect of pCO2, temperature, and UF volume on CBF is similar at T1, T2, and T3. The pH model could be interpreted by adding the effect of the single term ‘pH’ and of the interaction term ‘pH*T2,’ yielding a net negative effect of pH on CBF at T2 as compared with T1.

  • b P<0.01.

  • c P<0.001.

  • d P<0.05.