Table 4.
Respiratory variability and extubation outcomes.
| MV | ETT-CPAP | |||||
|---|---|---|---|---|---|---|
| Success | Failure | P values | Success | Failure | P values | |
| BB intervals (s) | ||||||
| SDBB | 0.55 [0.27–0.56] | 1.02 [0.90–1.42] | 0.014 | 0.36 [0.27–0.39] | 0.61 [0.42–1.31] | 0.014 |
| CVBB | 0.48 [0.36–0.67] | 0.50 [0.38–0.77] | 0.945 | 0.37 [0.33–0.39] | 0.40 [0.31–0.61] | 0.945 |
| SDSDBB | 0.60 [0.34–0.73] | 1.07 [1.00–1.70] | 0.014 | 0.40 [0.37–0.45] | 0.70 [0.52–1.32] | 0.002 |
| TIBB | 2.92 [2.46–3.36] | 3.65 [2.67–4.15] | 0.628 | 3.06 [2.69–3.76] | 3.04 [2.64–3.45] | 0.945 |
| Breath area (μV·s) | ||||||
| SDArea | 248 [169–346] | 347 [315–419] | 0.294 | 269 [220–392] | 384 [304–473] | 0.366 |
| CVArea | 0.67 [0.62–0.78] | 0.91 [0.86–0.98] | 0.014 | 0.58 [0.53–0.65] | 0.83 [0.64–0.99] | 0.013 |
| SDSDArea | 2789 [179–426] | 436 [404–467] | 0.294 | 334 [272–486] | 480 [379–631] | 0.366 |
| TIArea | 4.33 [3.08–5.67] | 3.86 [3.45–4.69] | 0.534 | 5.43 [3.76–7.45] | 4.60 [3.44–6.79] | 0.534 |
| Neural Ti (s) | ||||||
| SDNTi | 0.29 [0.18–0.33] | 0.64 [0.55–0.81] | 0.014 | 0.20 [0.18–0.21] | 0.40 [0.27–0.57] | 0.035 |
| CVNTi | 0.60 [0.44–0.69] | 1.05 [0.84–1.33] | 0.008 | 0.42 [0.42–0.48] | 0.59 [0.53–0.93] | 0.001 |
| SDSDNTi | 0.41 [0.24–0.45] | 0.81 [0.68–1.16] | 0.022 | 0.25 [0.23–0.26] | 0.49 [0.37–0.74] | 0.014 |
| TINTi | 2.85 [2.36–3.39] | 3.52 [2.60–4.15] | 0.534 | 2.65 [2.49–3.35] | 3.46 [2.80–4.37] | 0.347 |
| Neural Te (s) | ||||||
| SDNTe | 0.35 [0.21–0.43] | 0.62 [0.48–0.70] | 0.014 | 0.27 [0.20–0.30] | 0.37 [0.26–1.04] | 0.234 |
| CVNTe | 0.53 [0.37–0.57] | 0.75 [0.73–0.79] | 0.021 | 0.42 [0.35–0.46] | 0.63 [0.49–0.96] | 0.021 |
| SDSDNTe | 0.37 [0.27–0.56] | 0.76 [0.54–0.89] | 0.073 | 0.32 [0.28–0.35] | 0.43 [0.33–1.44] | 0.138 |
| TINTe | 4.04 [3.09–4.81] | 5.01 [4.81–5.83] | 0.138 | 3.57 [3.38–4.49] | 3.76 [3.44–6.77] | 0.836 |
| Breath amplitude (μV) | ||||||
| SDAmp | 6.29 [3.76–7.13] | 6.40 [5.31–8.67] | 0.534 | 4.97 [4.64–9.05] | 7.66 [6.56–8.92] | 0.445 |
| CVAmp | 0.58 [0.55–0.62] | 0.74 [0.71–0.79] | 0.001 | 0.49 [0.46–0.53] | 0.70 [0.60–0.75] | 0.002 |
| SDSDAmp | 7.57 [4.17–8.69] | 8.26 [6.87–9.68] | 0.062 | 6.45 [6.16–11.31] | 9.87 [8.76–10.61] | 0.445 |
| TIAmp | 2.55 [1.90–3.14] | 2.53 [2.12–3.15] | 0.836 | 2.48 [2.14–3.63] | 2.42 [1.70–3.29] | 0.534 |
| Breath width (s) | ||||||
| SDWidth | 0.13 [0.12–0.17] | 0.19 [0.14–0.31] | 0.234 | 0.11 [0.10–0.13] | 0.16 [0.12–0.20] | 0.138 |
| CVWidth | 0.36 [0.32–0.43] | 0.46 [0.37–0.70] | 0.279 | 0.33 [0.28–0.34] | 0.38 [0.32–0.49] | 0.276 |
| SDSDWidth | 0.17 [0.15–0.24] | 0.26 [0.19–0.45] | 0.181 | 0.16 [0.14–0.18] | 0.23 [0.16–0.27] | 0.138 |
| TIWidth | 2.56 [2.45–2.74] | 2.75 [2.53–2.89] | 0.628 | 2.30 [2.20–2.78] | 2.73 [2.37–3.34] | 0.389 |
MV mechanical ventilation, ETT-CPAP endotracheal tube continuous positive airway pressure, BB breath to breath, SD standard deviation, CV coefficient of variation, SDSD standard deviation of successive differences, TI triangular index, NTi neural inspiratory time, Ti inspiratory time, Te expiratory time.
Values are presented as median [IQR].