Table 7.
Measurement of heart-rate variability during SBT and postextubation periods
| Frequency-domain measures | SBT | Postextubation | P value a | P value b |
|---|---|---|---|---|
| VLF (ln(ms2)) |
|
|
|
|
| Successful extubation |
6.4 (1.7) |
6.9 (1.2) |
0.015 |
0.003 |
| Extubation failure |
6.1 (1.4) |
5.5 (1.9) |
|
0.187 |
| LF% (nu) |
|
|
|
|
| Successful extubation |
43 (23) |
43 (19) |
0.783 |
|
| Extubation failure |
26 (12) |
27 (18) |
|
|
| HF% (nu) |
|
|
|
|
| Successful extubation |
43 (18) |
44 (15) |
0.956 |
|
| Extubation failure |
51 (14) |
52 (15) |
|
|
| TP (ln(ms2)) |
|
|
|
|
| Successful extubation |
7.7 (1.0) |
8.1 (0.8) |
0.025 |
0.004 |
| Extubation failure |
7.5 (1.1) |
7.2 (0.9) |
|
0.182 |
| LF/HF (ln(ratio)) |
|
|
|
|
| Successful extubation |
1.0 (0.3) |
1.0 (0.2) |
0.954 |
|
| Extubation failure | 0.9 (0.1) | 0.9 (0.2) |
aFor comparison between successful extubation and extubation-failure groups.
bFor comparison between spontaneous-breathing trial and postextubation periods within a group.
Data are presented as mean (standard deviation).
HF, high frequency; LF, low frequency; ln, natural logarithm; nu, normalized unit; SBT, spontaneous breathing trial; TP, total power. VLF, very low frequency.