Table 1.
Values of HRV of premature infants related to length of hospital stay
| Moment I | Moment II | p value | |
|---|---|---|---|
| HR (bpm) | 154,6 (154) ± 7,01 | 162 (162) ± 12,44 | 0.0694 |
| SDNN (ms) | 15.14 (12.60) ± 9.87 | 12.38 (9.10) ± 9.01 | 0.170a |
| rMSSD (ms) | 5.38 (3.60) ± 3.32 | 11.42 (6.60) ± 12.02 | 0.135a |
| pNN50 (%) | 0.22 (0) ± 0.31 | 2.19 (0.30) ± 4.77 | 0.170a |
| SD1 (ms) | 1.28 (0.60) ± 1.79 | 8.06 (4.70) ± 8.51 | 0.0007a* |
| SD2 (ms) | 21.80 (18.50) ± 13.76 | 27.26 (24.00) ± 16.68 | 0.166a |
| SD1/SD2 | 7.55 (7) ± 4.74 | 2.70 (2.22) ± 1.73 | 0.003* |
| ApEn | 0.87 (0.81) ± 0.46 | 1.03 (1.12) ± 0.44 | 0.12a |
| SampEn | 0.81 (0.70) ± 0.33 | 1.07 (1.14) ± 0.23 | 0.0069* |
HR heart rate, bpm Beats per minute, ms milliseconds, % percentage, HR heart rate, SDNN standard deviation of the mean of all normal RR intervals, rMSSD square root mean squared differences between adjacent normal RR intervals, pNN50 percentage of pairs of consecutive RR intervals whose difference is greater than or equal to 50 m, SD1 standard deviation of instantaneous beat-to-beat variability, SD2 standard deviation of long-term continuous RR intervals, SD1 / SD2 ratio between SD1 and SD2, ApEn approximate entropy, SampEn entropy of the sample
aMann-Whitney
*p < 0.05