Breathing pattern, inspiratory effort and lung mechanics in different settings
| Baseline | HFOT 20 (closed) | HFOT 20 (open) | HFOT 30 (closed) | HFOT 30 (open) | NIV | |
|---|---|---|---|---|---|---|
| TI,p (seconds) | 0.95±0.2 | 0.85±0.4 | 0.96±0.2 | 0.94±0.3 | 0.92±0.3 | 1.00±0.2 |
| TE,p (seconds) | 1.94±0.4 | 2.35±0.4* | 2.19±0.5* | 2.30±0.5* | 2.20±0.3* | 2.61±1.0* |
| Breathing frequency (breaths/min) | 24.8±2.3 | 19.01±5.2† | 20.8±5.8 | 18.7±3.6† | 19.64±2.8 | 17.8±3.8† |
| Tidal volume (mL) | 314.50±84 | 391.22±106‡ | 364.22±66 | 456.20±100‡ | ||
| Pdi swing (cmH2O) | 13.5±6.7 | 8.7±4.1§ | 12±5.8 | 8.2±3.7§ | 10.2±5.2§ | 5.1±2.2§¶ |
| PTPdi/min (cmH2Oxs/min) | 238.3±82.1 | 164.2±51.3** | 172.7±45.4** | 143.2±48.9** | 157.3±56.9** | 101.7±42.9**†† |
| PEEPi,dyn (cmH2O) | 2.12±0.9 | 1.48±0.7‡‡ | 1.03±0.6‡‡ | 0.9±0.02‡‡ |
*p=0.006 HFOT 20 closed versus baseline; p=0.01 HFOT 20 open versus baseline; p=0.007 HFOT 30 closed versus baseline; p=0.02 HFOT 30 open versus baseline; p=0.002 NIV versus baseline.
†p=0.022 HFOT 20 closed versus baseline; p=0.007 HFOT 30 closed versus baseline; p=0.002 NIV versus baseline.
‡p=0.015 HFOT 20 closed versus baseline; p=0.007 NIV versus baseline.
§p=0.005 HFOT 20 closed versus baseline; p=0.005 HFOT 30 closed versus baseline; p=0.03 HFOT 30 open versus baseline; p=0.001 NIV versus baseline.
¶p<0.003 NIV versus HFOT 20 closed; p=0.003 NIV versus HFOT 20 open; p=0.007 NIV versus HFOT 30 closed; p=0.005 NIV versus HFOT 30 open.
**p=0.005 HFOT 20 closed versus baseline; p=0.002 HFOT 20 open versus baseline; p=0.004 HFOT 30 closed versus baseline; p=0.015 HFOT 30 open versus baseline; p=0.001 NIV versus baseline.
††p<0.004 NIV versus HFOT 20 closed; p=0.006 NIV versus HFOT 20 open; p=0.016 NIV versus HFOT 30 closed; p=0.02 NIV versus HFOT 30 open.
‡‡p=0.01 HFOT 20 closed versus baseline; p=0.003 HFOT 30 closed versus baseline; p=0.001 NIV versus baseline.
Data are presented as mean±SD.
HFOT, high flow oxygen therapy; NIV, non-invasive ventilation; Pdi, transdiaphragmatic pressure; PEEPi,dyn, intrinsic dynamic positive end expiratory pressure; PTPdi, pressure–time product of the transdiaphragmatic; TE,p, patient's expiratory time; TI,p, patient's inspiratory time.