Table 2.
Breathing pattern, respiratory muscle output and continuous positive airway pressure level during spontaneous breathing at clinical and two physiological settings of continuous positive airway pressure in the total population.a
| Spontaneous breathing | Clinical CPAP | Physiological CPAP | Physiological CPAP+1 cmH2O | |
|---|---|---|---|---|
| Respiratory parameters | ||||
| fR (breaths/min) | 49 ± 14 | 44 ± 21 | 38 ± 16b | 36 ± 18 |
| TI/TTOT | 0.5 ± 0.1 | 0.4 ± 0.1 | 0.4 ± 0.1c | 0.4 ± 0.1 |
| Respiratory muscle output | ||||
| Poes swing (cmH2O) | 31 ± 15 | 21 ± 10d | 11 ± 5b | 14 ± 6 |
| Pdi swing (cmH2O) | 26 ± 8 | 20 ± 8d | 12 ± 6b | 15 ± 7 |
| Pgas swing (cmH2O) | 4 ± 2 | 3 ± 1 | 2 ± 1c | 2 ± 1 |
| Expiratory Pgas swing (cmH2O) | 4 ± 4 | 3 ± 5 | 1 ± 1 | 2 ± 2 |
| PTPoes/breath (cmH2O/s) | 12 ± 6 | 9 ± 6 | 6 ± 5b | 9 ± 9 |
| PTPdi/breath (cmH2O/s) | 11 ± 4 | 9 ± 6 | 6 ± 4b | 8 ± 6 |
| PTPoes/min (cmH2O/s/min) | 571 ± 340 | 359 ± 227 | 183 ± 119e | 244 ± 161 |
| PTPdi/min (cmH2O/s/min) | 452 ± 146 | 350 ± 164 | 201 ± 108b | 239 ± 173 |
| CPAP level (cmH2O) | NA | 8 ± 2 | 10 ± 2 | 11 ± 2 |
aCPAP: continuous positive airway pressure, fR: respiratory rate, NA: not applicable, Poes: oesophageal pressure, Pdi: transdiaphragmatic pressure, Pgas: gastric pressure, PTP: pressure-time product, TI/TTOT: inspiratory time/total respiratory cycle time ratio. bP < 0.05 between physiological CPAP and spontaneous breathing or clinical CPAP. cP < 0.05 between spontaneous breathing and physiological CPAP. dP < 0.05 between spontaneous breathing and clinical CPAP. eP < 0.05 between physiological CPAP and spontaneous breathing, physiological CPAP or physiological CPAP+1 cmH2O.