Table 3.
DCS variables during the studies among N = 49 days by IVH status.
| Variables | Total (N = 49 days) | No IVH (N = 27) | IVH grade I or II (N = 9) | IVH grade III or IV (N = 13) | P val* |
|---|---|---|---|---|---|
| Duration of the measurement (h/day) | 4.3 (3.4–5.8) | 3.7 (3.0–5.8) | 5.0 (4.1–5.8) | 5.0 (3.6–6.2) | 0.27a |
| Total data length after MA rejection (h/day) | 3.9 ± 1.4 | 3.6 ± 1.5 | 4.2 ± 1.2 | 4.3 ± 1.4 | 0.33 |
| Motion artifact (%/day) | 9.6 (4.9–15.2) | 7.4 (4.5–19.8) | 11.8 (9.6–20.4) | 7.8 (2.9–12.7) | 0.28a |
| SBFid (daily median, e-8 * cm2/s/day) | 5.1 (3.1–6.7) | 5.1 (3.2–6.2) | 7.0 (4.3–9.4) | 3.7 (2.7–5.4) | 0.04 |
| CBFi (daily median, e-8 * cm2/s/day) | 3.2 (2.7–4.4) | 3.6 (2.8–4.7) | 3.0 (2.8–4.1) | 2.7 (2.1–3.4) | 0.41a |
| CVSBFi (SBFi coefficient of variation) (5-min sliding window median, /day) | 0.107 (0.09–0.13) | 0.124 (0.10–0.15) | 0.107 (0.09–0.12) | 0.096 (0.08–0.12) | 0.76b |
| CVCBFi (5-min sliding window median, /day) | 0.069 ± 0.018 | 0.070 ± 0.019 | 0.069 ± 0.020 | 0.067 ± 0.015 | 0.95 |
| CVCBFi_20 (20-min sliding window median, /day) | 0.089 ± 0.022 | 0.090 ± 0.025 | 0.088 ± 0.021 | 0.085 ± 0.015 | 0.95 |
| CVCBFi_40 (40-min sliding window median, /day) | 0.101 ± 0.027 | 0.105 ± 0.032 | 0.100 ± 0.021 | 0.094 ± 0.016 | 0.77 |
| RiSC (3-min sliding window mean, /day) | 0.56 ± 0.14 | 0.53 ± 0.14 | 0.49 ± 0.12 | 0.65 ± 0.12 | 0.17 |
| TRiSC (s/day) | 2.8 (1.5–4.5) | 3.1 (1.5–4.8) | 3.7 (2.8–4.4) | 2.5 (1.5–3.3) | 0.33c |
| Pressure passiveness indices | |||||
| Available | 17 (35%) | 11 (41%) | 2 (22%)e | 4 (31%) | 0.66 |
| MAP × CBF cross-correlation (3-min sliding window mean, /day) | 0.35 ± 0.17 | 0.30 ± 0.11 | 0.22 ± 0.11 | 0.55 ± 0.16 | 0.14 |
| Delay of MAP × CBF correlation (mean, seconds/day) | 6.6 ± 3.4 | 7.7 ± 3.3 | 7.4 ± 2.4 | 3.3 ± 1.7 | 0.29 |
Significant values are in bold.
MA Motion artifact; *P values were obtained using a linear mixed model (when possible) to account for repeated measures in each subject. The P-values for categorical variables were obtained using Fisher’s exact test without accounting for repeated measures in each subject.; alog10() transformation was applied; blogit() transformation was applied; cSquare root transformation was applied; dThe variable passed the normality test but is presented in median (25–75th) for easy comparison with CBFi; eThe two measurements were from one subject; Data are presented as n (column %) for categorical variables, except when presented as a mean ± SD for normally distributed variables or when presented as a median (25–75th) for non-normal variables.