Table 2.
Clinical, echographic, and spirometric characteristics of the overall population and of successfully and unsuccessfully weaned patients
| All (n = 51) | Weaning success (n = 34) | Weaning failure (n = 17) | P value* | |
|---|---|---|---|---|
| SBT ventilatory parameters | ||||
| RR (breaths/min) | 20 ± 6 | 18 ± 5 | 24 ± 7 | <0.0001 |
| VT (ml/kg IBW) | 5.9 ± 2.3 | 6.3 ± 2.2 | 5.1 ± 2.2 | 0.084 |
| DD (mm) | 14.0 (9.0–17.7) | 15.5 (11.7–23.0) | 7.0 (6.0–14.7) | <0.0001 |
| D-RSBI (breaths/min/mm) | 1.7 (0.8–2.7) | 1.2 (0.8–1.9) | 2.7 (1.7–4.1) | <0.0001 |
| RSBI (breaths/min/L) | 47 (33–61) | 43 (32–52) | 63 (37–90) | 0.012 |
| MIP (cmH2O) | 26 (20–31) | 28 (22–36) | 22 (19–25) | 0.020 |
| MV parameters prior to SBT | ||||
| PS (cmH2O) | 7.2 ± 2.8 | 7.3 ± 3.1 | 7.1 ± 2.0 | 0.878 |
| PEEP (cmH2O) | 6.2 ± 1.3 | 6.1 ± 1.4 | 6.5 ± 1.2 | 0.281 |
| Duration of PEEP >8 cmH2O (h) | 43 ± 23 | 34 ± 13 | 69 ± 37 | 0.003 |
| Intra-abdominal pressure (cmH2O) | 13 ± 2 | 12.7 ± 1.7 | 13.1 ± 0.8 | 0.781 |
| Length of MV until SBT (h) | 69 (53–173) | 57 (49–66) | 169 (73–296) | 0.001 |
| ICU length of stay (days) | 5.0 (3.0–9.2) | 3.0 (2.3–4.5) | 9.2 (6.1–15.3) | 0.001 |
| Hospital length of stay (days) | 15 (9–23) | 10 (8–13) | 26 (19–29) | 0.001 |
| Hospital mortality | 9 (18) | 3 (9) | 6 (35) | 0.045 |
*Comparison between weaning success and failure using Mann-Whitney U tests to compare medians, unpaired Student’s t tests or to compare means, or chi-square test to compare the proportions
Normally distributed data are shown as mean ± standard deviation; not normally distributed data as median (interquartile range); percentage data are shown as n (%)
DD diaphragmatic displacement, D-RSBI diaphragmatic rapid shallow breathing index, ICU intensive care unit, IBW ideal body weight, MIP maximum inspiratory pressure, MV mechanical ventilation, PEEP positive end-expiratory pressure, PS pressure support, RR respiratory rate, RSBI rapid shallow breathing index (RR/VT), SBT spontaneous breathing trial, VT tidal volume