Results
| Constant O2-flow, CFOS, n=50 | Automatic O2-flow, ATOS, n=50 | P valuex) | Median effect (95% CI) automatic—constant | |
| Primary outcome | ||||
| ESWT Time, s | 333.50 (214, 581) | 522.5 (277, 1200) | 1.203E–04 | 144.5 (54 to 241.5) |
| Secondary outcomes | ||||
| ESWT Distance, m | 310 (200, 620) | 465 (200, 1030) | 2.602E–04 | 150 (60 to 31) |
| Oxygen Mean O2-flow rate | 3.0 (3.0, 4.0) | 4.5 (3.2, 6.1) | 1.000E–05 | 1.34 (0.68 to 2.14) |
| Blood gas analyses | ||||
| PO2rest, mm Hg | 80.2 (73.1, 90.6) | 65.35 (62.6, 68.1) | 1.582E–14 | –17.8 (–22.1 to –13.8) |
| PO2post, mm Hg | 61.35 (55.0, 64.5) | 71.5 (64.2, 75.8) | 3.304E–08 | 8.85 (6.35 to 11.9) |
| PCO2rest, mm Hg | 42.5 (39.8, 46.1) | 40.85 (39.2, 48.2) | 0.87 | |
| PCO2post, mm Hg | 50.45 (46.7, 54.0) | 50.45 (46.8, 54.8) | 0.41 | |
| Phrest | 7.41 (7.39, 7.43) | 7.42 (7.40, 7.43) | 0.64 | |
| Phpost | 7.35 (7.32, 7.38) | 7.34 (7.32, 7.37) | 0.19 | |
| BErest, mmol/L | 1.75 (0.30, 3.20) | 1.20 (0.10, 3.60) | 0.68 | |
| BEpost, mmol/L | 0.80 (–0.80, 2.10) | 0.50 (–1.10, 2.40) | 0.52 | |
| HCO3rest, mmol/L | 26.0 (24.70, 27.30) | 25.4 (24.50, 27,60) | 0.97 | |
| HCO3post, mmol/L | 25.0 (23.60, 26.10) | 24.80 (23.40, 26.50) | 0.78 | |
| SaO2rest, % | 95.0 (94.60, 96.60) | 93.08 (91.70, 93.50) | 1.582E–14 | -3.0 (-3.45 to -2.6) |
| SaO2post, % | 89.19 (86.50, 91.30) | 92.75 (91.30, 94.04) | 1.450E–08 | 3.17 (2.15 to 4.37) |
| Lactaterest, mmol/L | 1.19 (0.99, 1.67) | 1.09 (0.88, 1.45) | 0.23 | |
| Lactatepost, mmol/L | 1.90 (1.50, 2.62) | 1.85 (1.14, 2.40) | 4.134E–02 | –0.135 (–0.29 to –0.005) |
| SenTec digital monitor | ||||
| SpO2rest, % | 96.0 (95.0, 98.0) | 93.0 (93.0, 95.0) | 2.286E–11 | –3 (–3.5 to –2.5) |
| SpO2isotime_100%, % | 89.0 (86.0, 93.0) | 92.0 (90.0, 94.0) | 5.275E–04 | 3 (1 to 4) |
| SpO2post, % | 89.0 (86.0, 93.0) | 93.0 (92.0, 94.0) | 1.758E–04 | 3 (1.5 to 5) |
| SpO2min, % | 88 .0 (85, 91) | 87.5 (83.0, 89.0) | 0.05 | |
| SpO2max, % | 97.0 (96.0, 99.0) | 95.0 (94.0, 96.0) | 1.122E–09 | –2 (–2.5 to –1.5) |
| SpO2mean, % | 92.0 (89.0, 94.0) | 92.0 (91.0, 93.0) | 0.77 | |
| Time to SpO2 <90%, s |
n=32
102.0 (73.0, 158.0) |
n=39
55.0 (19.0, 74.0) | 6.937E–06 | –71.8 (–101 to –47) |
| Time to SpO2 <85%, s | n=11 152.0 (112.0, 194.0) | n=16 81.5 (61.0, 137.5) | 0.11 | |
| TcPCO2rest, mm Hg | 43.0 (39.8, 46.1) | 42.6 (39.4, 46.3) | 0.19 | |
| TcPCO2isotime_100%, mm Hg | 47.7 (45.4, 50.9) | 47.7 (44.6, 53.7) | 0.93 | |
| TcPCO2post, mm Hg | 47.75 (45.4, 50.9) | 48.0 (45.5, 53.6) | 0.57 | |
| TcPCO2max, mm Hg | 48.9 (45.8, 51.75) | 49.2 (46.4, 55.2) | 0.42 | |
| Heart raterest, b/min | 83.0 (78.0, 88.0) | 84.0 (79.0, 93.0) | 3.859E–02 | 2 (0 to 4.5) |
| Heart rateisotime_100%, b/min | 100.5 (95.0, 106.0) | 100.5 (95.0, 108.0) | 0.17 | |
| Heart ratepost, b/min | 101.0 (95.0, 107.0) | 103.0 (96.0, 112.0) | 4.381E–03 | 3.5 (1 to 5.5) |
| Heart ratemax, b/min | 104.5 (99.0, 116.0) | 106.0 (99.0, 117.0) | 0.06 | |
| Respiratory rate | ||||
| Respiratory raterest, 1 /min | 18.0 (14.0, 24.0) | 20 (17.0, 24.0) | 1.079E–03 | 2 (1 to 3.5) |
| Respiratory rateisotime_100%, 1 /min | 31.0 (24.0, 45.5) | 31.0 (23.5, 44.0) | 0.25 | |
| Respiratory ratepost, 1 /min | 29.0 (24.0, 34.0) | 29.0 (21.0, 34.0) | 0.40 | |
| Borg scale | ||||
| Dyspnoearest, points | 1.0 (0.0, 2.0) | 1.0 (0.0, 2.0) | 0.96 | |
| Dyspnoeapost, points | 6.0 (5.0, 7.0) | 5.0 (4.0, 7.0) | 1.914E–04 | –0.5 (–1 to –0.5) |
| Leg fatiguerest, points | 1.0 (0.0, 2.0) | 1.0 (0.0, 2.0) | 0.79 | |
| Leg fatiguepost, points | 4.0 (3.0, 6.0) | 4.0 (3.0, 5.0) | 0.10 | |
Differences with p values<0.01 are presented in bold.
Note: Median effects are not necessarily medians of differences; x)non-parametric 2×2 crossover models based on Monte Carlo simulations using Wilcoxon (mid rank) test. P-values are unadjusted for multiple comparisons.
Data presented as median (IQR).
ATOS, automatically titrating oxygen system; BE, base excess; CFOS, constant flow oxygen system; ESWT, endurance shuttle walk test; HCO3, hydrogen carbonate; O2, oxygen; PCO2, partial pressure of carbon dioxide; pH, potential of hydrogen; PO2, partial pressure of oxygen; SaO2, oxygen saturation measured by blood gas analyses; SpO2, oxygen saturation; TcPCO2, transcutaneous carbon dioxide.