Mean (SE) daytime arterial blood gas tensions and spontaneous ventilation, hypercapnic responses, and polysomnography parameters after 4 weeks each of pressure and volume ventilation
| Outcome | Pressure | Volume | p | pC |
|---|---|---|---|---|
| *Unassisted ventilation. | ||||
| p, raw probability; pC, Hochberg corrrection for multiple end points; Pi,max, maximal inspiratory mouth pressure; Pe,max, maximal expiratory mouth pressure; SNIP, sniff nasal inspiratory pressure; VTe, expired tidal volume; RRspon, spontaneous respiratory rate; MVe, expired minute ventilation; P0.1, pressure at mouth 100 ms after an occluded inspiratory effort; ΔVE/ΔPco2, slope of ventilatory response curve to inspired carbon dioxide; ΔP0.1/ΔPco2, slope of P0.1 against inspired carbon dioxide; RDI, respiratory disturbance index, number of apnoeas and hypopnoeas per hour of sleep; Tcco2, transcutaneous carbon dioxide; RRvent, respiratory rate during assisted ventilation; IPpeak, peak inspiratory pressure; IPmean, mean inspiratory pressure; Ti, measured inspiratory time; Te, measured expiratory time; TST, total sleep time; REM, rapid eye movement sleep; NREM, non-rapid eye movement sleep. | ||||
| pH* | 7.38 (0.01) | 7.38 (0.01) | 0.56 | 0.56 |
| HCO3− | 28.6 (0.68) | 29.5 (0.66) | 0.07 | 0.28 |
| Pao2 (kPa) | 9.00 (0.23) | 8.68 (0.36) | 0.18 | 0.36 |
| Paco2 (kPa) | 6.38 (0.12) | 6.61 (0.16) | 0.09 | 0.27 |
| Sao2 | 92.3 (0.75) | 90.7 (1.17) | 0.04 | 0.20 |
| Pi,max (cm H2O) | −36.3 (5.1) | −38.5 (4.9) | 0.47 | 1.00 |
| Pe,max (cm H2O) | 66.2 (10.6) | 72.1 (10.7) | 0.31 | 1.00 |
| SNIP (cm H2O) | −36.0 (5.3) | −37.7 (5.8) | 0.66 | 1.00 |
| FEV1 (l) | 0.60 (0.04) | 0.61 (0.04) | 0.57 | 0.86 |
| FVC (l) | 0.72 (0.06) | 0.76 (0.06) | 0.86 | 1.00 |
| Spontaneous ventilation | ||||
| VTe (ml) | 439 (26) | 396 (34) | 0.29 | 0.58 |
| RRspon (bpm) | 25.4 (2.1) | 28.4 (2.2) | 0.09 | 0.36 |
| MVe (l/min) | 10.8 (0.5) | 10.8 (0.6) | 0.80 | 0.80 |
| P0.1 (cm H2O) | −1.53 (0.17) | −1.26 (0.11) | 0.18 | 0.54 |
| Hypercapnic responses | ||||
| ΔVE/ΔPco2 (l/min/kPa) | 2.87 (0.41) | 3.59 (0.63) | 0.15 | 0.31 |
| MVe at 8 kPa (l/min) | 14.6 (1.2) | 13.7 (1.0) | 0.45 | 0.45 |
| ΔP0.1/ΔPco2 (cm H2O/kPa) | −0.91 (0.17) | −0.72 (0.12) | 0.07 | 0.21 |
| P0.1 at 8 kPa (cm H2O) | −2.60 (0.44) | −1.90 (0.35) | 0.008 | 0.03 |
| Polysomnography | ||||
| Sao2 (%) | 92.8 (0.9) | 91.8 (1.1) | 0.20 | 1.00 |
| Sao2 <90% (minutes) | 73 (32) | 107 (40) | 0.11 | 1.00 |
| RDI (/hour) | 0.7 (0.7) | 0 (0) | 0.29 | 1.00 |
| Tcco2 (kPa) | 4.3 (0.8) | 4.7 (0.6) | 0.76 | 1.00 |
| VTe (ml) | 548 (75) | 546 (78) | 0.98 | 1.00 |
| MVe (l/min) | 8.34 (0.91) | 8.38 (1.3) | 0.58 | 1.00 |
| Minute leak (l/min) | 13.80 (1.93) | 5.87 (1.03) | 0.001 | 0.01 |
| Peak inspiratory flow (l/min) | 149 (21) | 152 (21) | 0.85 | 1.00 |
| RRvent (bpm) | 15 (0.3) | 15.6 (0.3) | 0.19 | 1.00 |
| IPpeak (cm H2O) | 24.2 (1.1) | 23.4 (1.1) | 0.85 | 1.00 |
| IPmean (cm H2O) | 20.9 (1.1) | 14.8 (0.8) | 0.001 | 0.008 |
| Ti (s) | 1.53 (0.10) | 1.33 (0.05) | 0.07 | 0.56 |
| Te (s) | 2.30 (0.13) | 2.38 (0.10) | 0.58 | 1.00 |
| Ti/TiTOT | 0.40 (0.03) | 0.36 (0.02) | 0.11 | 0.75 |
| Total sleep time (TST) (min) | 394 (16) | 416 (13) | 0.10 | 1.00 |
| Latency (min) | 52 (10) | 41 (8) | 0.38 | 1.00 |
| Efficiency (%) | 77 (8) | 85 (2) | 0.24 | 1.00 |
| REM (% TST) | 12 (2) | 13 (2) | 0.52 | 1.00 |
| NREM 1+2 (% TST) | 55 (6) | 54 (6) | 0.85 | 1.00 |
| NREM 3+4 (% TST) | 26 (6) | 25 (5) | 0.68 | 1.00 |
| Respiratory arousals (/hour) | 0.8 (0.4) | 0.0 (0.0) | 0.10 | 1.00 |
| Non-respiratory arousals (/hour) | 16.0 (2.2) | 18.4 (4.6) | 0.44 | 1.00 |
| Ventilator hours (/night at home) | 8.1 (0.7) | 8.4 (1.1) | 0.25 | 0.25 |