Table 3.
Mean differences (MD) in heart rate variability (HRV) between the different severities of neonatal hypoxic ischemic encephalopathy (HIE) by study
| Severe HIE compared with mild HIE | ||||||||
| Number in the statistical analysis | Time of assessment | TH | HRV measures | Mean, 95% CI (severe) | Mean, 95% CI (mild) | MD, 95% CI | P-values | |
| Goulding et al. 2015, Ireland [21] |
Severe, n = 17 Mild, n = 40 |
12–48 h | No |
SDNN (ms) TINN (ms) Mean VLF (ms2) Mean LF (ms2) Mean HF (ms2) LF/HF ratio |
8.5 (5.1, 14) 24.5 (14.8, 40.6) 27.5 (9.7, 78.2) 13.2 (4.1, 42.8) 4 (2.4, 5.8) 3.7 (2.4, 5.9) |
18.6 (15.4, 22.4) 50 (40.6, 61.6) 138.8 (95.3, 202.1) 84.1 (54.4, 130.2) 16.8 (10, 28.2) 5.6 (4.4, 7.2) |
−10.1 (− 15.8, − 4.4) − 25.5 (− 42.2, − 8.8) − 111.3 (− 175.6, − 47.0) − 70.9 (− 113.4, − 28.4) − 12.8 (− 24.1, − 1.6) − 1.9 (− 4.1, 0.3) |
< 0.01 < 0.01 < 0.01 < 0.01 0.03 0.09 |
|
Goulding et al. 2017, Ireland [22] |
Severe, n = 60 Mild, n = 110 |
6–72 h | Yes |
SDNN (ms) TINN (ms) Mean VLF (ms2) Mean LF (ms2) Mean HF (ms2) LF/HF ratio |
10.1 (7.6, 13.4) 26.8 (20.5, 35) 40.1 (21.7, 74.3) 18.1 (9.3, 35.2) 5.8 (3.2, 10.7) 3.3 (2.3, 4.7) |
20.4 (17.2, 24.2) 51.9 (43.9, 61.6) 162.1 (112.8, 232.5) 92.1 (61.9, 137) 17.5 (12, 25.4) 5.6 (4.5, 6.9) |
−10.3 (− 14.8, − 5.8) − 25.1 (− 36.6, − 13.6) − 122.0 (− 187.4, − 56.6) − 74.0 (− 113.7, − 34.3) − 11.7 (− 19.4, − 4.0) − 2.3 (− 4, − 0.6) |
< 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 |
| Moderate HIE compared with mild HIE | ||||||||
| Number in the statistical analysis | Time of assessment | TH | HRV measures | Mean, 95% CI (moderate) |
Mean, 95% CI (mild) |
MD, 95% CI | P-values | |
| Goulding et al. 2015, Ireland [21] |
Moderate, n = 16 Mild, n = 40 |
12–48 h | No |
SDNN (ms) TINN (ms) Mean VLF (ms2) Mean LF (ms2) Mean HF (ms2) LF/HF ratio |
11.2 (7.8, 16.1) 28 (18.8, 41.6) 57 (28.7, 113) 29.4 (12.6, 68.5) 3.6 (1.3, 7.6) 9.4 (6.3, 13.9) |
18.6 (15.4, 22.4) 50 (40.6, 61.6) 138.8 (95.3, 202.1) 84.1 (54.4, 130.2) 16.8 (10, 28.2) 5.6 (4.4, 7.2) |
−7.4 (− 12.8, − 2.0) − 22.0 (− 37.5, − 6.5) − 81.8 (− 149.8, − 13.8) − 54.7 (− 101.8, − 7.6) − 13.2 (− 23.2, − 3.2) 3.7 (− 0.3, 7.9) |
< 0.01 < 0.01 0.02 0.03 0.01 0.08 |
| Goulding et al. 2017, Ireland [22] |
Moderate, n = 48 Mild, n = 110 |
6–72 h | Yes |
SDNN (ms) TINN (ms) Mean VLF (ms2) Mean LF (ms2) Mean HF (ms2) LF/HF ratio |
15.1 (11.2, 20.3) 42.5 (31.8, 56.8) 90.9 (48.5, 170.4) 52.8 (9.3, 107.7) 16.8 (8.7, 32.8) 3.5 (2.3, 5.1) |
20.4 (17.2, 24.2) 51.9 (43.9, 61.6) 162.1 (112.8, 232.5) 92.1 (61.9, 137) 17.5 (12, 25.4) 5.6 (4.5, 6.9) |
−5.3 (− 11, 0.4) − 9.4 (− 24.7, 5.9) − 71.2 (− 156.6, 14.2) − 39.3 (− 101.2, 22.6) − 0.7 (− 14.5, 13.1) − 2.1 (− 3.9, − 0.3) |
0.08 0.23 0.10 0.21 0.92 0.02 |
| Severe HIE compared with no HIE | ||||||||
| Number in the statistical analysis | Time of assessment | TH | HRV measures | Mean, 95% CI (severe) |
Mean, 95% CI (No HIE) |
MD, 95% CI | P-values | |
| Aliefendioglu et al. 2012, Turkey [19] |
Severe, n = 10 No HIE, n = 24 |
End of first postnatal week | No |
Mean LF (nu) Mean HF (nu) LF/HF ratio |
27.8 (19.7, 35.9) 48.9 (44.5, 53.5) 0.6 (0.4, 0.9) |
73.1 (70.3, 75.9) 20.3 (18.1, 22.5) 4 (3.3, 4.7) |
−45.3 (− 53.8, − 36.8) 28.6 (23.7, 33.5) − 3.4 (− 4.1, − 2.7) |
< 0.01 < 0.01 < 0.01 |
| Goulding et al. 2015, Ireland [21] |
Severe, n = 17 No HIE, n = 17 |
12–48 h | No |
SDNN (ms) TINN (ms) Mean VLF (ms2) Mean LF (ms2) Mean HF (ms2) LF/HF ratio |
8.5 (5.1, 14) 24.5 (14.8, 40.6) 27.5 (9.7, 78.2) 13.2 (4.1, 42.8) 4 (2.4, 5.8) 3.7 (2.4, 5.9) |
32.9 (27.9, 38.8) 106.4 (93.5, 119.3) 422.1 (296.8, 598.2) 375.7 (263.5, 535.6) 93.6 (61.7, 142) 4.4 (3.3, 5.9) |
−24.4 (−31.5, − 17.4) − 81.9 (− 100.1, − 63.6) − 394.6 (− 548.7, − 240.6) − 362.4 (− 499.9, − 225.0) − 89.7 (− 130.4, − 49.0) − 0.7 (− 2.9, 1.5) |
< 0.01 < 0.01 < 0.01 < 0.01 < 0.01 0.54 |
| Moderate HIE compared with no HIE | ||||||||
| Number in the statistical analysis | Time of assessment | TH | HRV measures | Mean, 95% CI (moderate) |
Mean, 95% CI (No HIE) |
MD, 95% CI | P-values | |
| Aliefendioglu et al. 2012, Turkey [19] |
Moderate, n = 12 No HIE, n = 24 |
End of first postnatal week | No |
Mean LF (nu) Mean HF (nu) LF/HF ratio |
57.8 (52.5, 63.1) 30.6 (26.6, 34.6) 1.9 (1.5, 2.4) |
73.1 (70.3, 75.9) 20.3 (18.1, 22.5) 4 (3.3, 4.7) |
−15.3 (− 21.3, − 9.3) 10.3 (5.8, 14.8) − 2.1 (− 2.9, − 1.3) |
< 0.01 < 0.01 < 0.01 |
| Goulding et al. 2015, Ireland [21] |
Moderate, n = 16 No HIE, n = 17 |
12–48 h | No |
SDNN (ms) TINN (ms) Mean VLF (ms2) Mean LF (ms2) Mean HF (ms2) LF/HF ratio |
11.2 (7.8, 16.1) 28 (18.8, 41.6) 57 (28.7, 113) 29.4 (12.6, 68.5) 3.6 (1.3, 7.6) 9.4 (6.3, 13.9) |
32.9 (27.9, 38.8) 106.4 (93.5, 119.3) 422.1 (296.8, 598.2) 375.7 (263.5, 535.6) 93.6 (61.7, 142) 4.4 (3.3, 5.9) |
−21.7 (−28.6, − 14.8) − 78.4 (− 95.6, − 61.2) − 365.1 (− 521.1, − 209.1) − 346.3 (− 485.2, − 207.4) − 90.1 (− 130.4, − 49.7) 4.9 (0.9, 9.0) |
< 0.01 < 0.01 < 0.01 < 0.01 < 0.01 0.02 |
| Severe or moderate HIE compared with mild or no HIE | ||||||||
| Number in the statistical analysis | Time of assessment | TH | HRV measures | Mean, 95% CI (severe/moderate) | Mean, 95% CI (mild/no HIE) | MD, 95% Cl | P-values | |
| Vergales et al. 2013, USA [20] |
Severe/moderate, n = 25 Mild/no HIE, n = 11 |
Within first 24 h | Yes | SDRR (ms) | 17.6 (13.8, 21.4) | 26.8 (20.1, 33.5) | −9.2 (− 16.5, − 1.9) | 0.02 |
| NDA | 1–7 days | Yes | SDRR (ms) | NDA | NDA | NDA | < 0.05 at day 1 and from day 3–7 | |
TH therapeutic hypothermia, CI confidence interval, SDNN standard deviation of normal-to-normal intervals, TINN triangular interpolation of normal-to-normal intervals, VLF very low frequency, LF low frequency, HF high frequency, nu, normal units, SDRR standard deviation of RR-intervals, NDA no data available