Table 4.
Reproducibility of sleep HRV measurements in twelve children with stable residual OSA after adenotonsillectomy.
| Variable | Preoperative | Postoperative | ICC | 95% CI | P-value |
|---|---|---|---|---|---|
| Time-domain indices | |||||
| N-N interval (ms) | 803 (685–870) | 829 (728–855) | 0.488 | −0.123–0.823 | 0.053 |
| SDNN (ms) | 83 (66–102) | 72 (59–111) | 0.553 | 0.011–0.846 | 0.026 |
| pNN50 (%) | 27 (21–47) | 27 (11–47) | 0.256 | −0.397–0.716 | 0.213 |
| RMSSD (ms) | 56 (44–83) | 55 (33–73) | 0.471 | −0.136–0.815 | 0.060 |
| Frequency-domain indices | |||||
| Total power (ms2) | 6,012 (3,350–13,102) | 4,604 (3,222–10,158) | 0.483 | −0.063–0.814 | 0.045 |
| VLF power (ms2) | 1,814 (1012–2797) | 1,901 (1,006–2,393) | 0.634 | 0.290–0.833 | 0.001 |
| LF power (ms2) | 935 (350–1688) | 645 (391–1,377) | 0.720 | 0.270–0.911 | 0.004 |
| LF% (%) | 40 (30–50) | 46 (31–59) | 0.557 | 0.034–0.846 | 0.023 |
| HF power (ms2) | 1,460 (677–2468) | 789 (358–2,547) | 0.335 | −0.318–0.756 | 0.146 |
| LF/HF ratio | 0.67 (0.43–1.01) | 1.047 (0.45–1.51) | 0.725 | 0.237–0.915 | 0.001 |
Bold font indicates statistically significant differences (P < 0.05).
CI, confidence interval; HF, high frequency; HRV, Heart rate variability; ICC, intraclass correlation coefficient; LF, low frequency; LF%, normalized LF power; N-N, normal-to-normal; OSA, obstructive sleep apnea; pNN50, proportion of N-N50 divided by the total number of N-N intervals; RMSSD, square root of the mean of the sum of the squares of di?erences between adjacent N-N intervals; SDNN, standard deviation of all N-N intervals; VLF, very low frequency.