Table 4.
Arterial blood gases
| 490 m | 1,650 m | 2,590 m | P-value | |
|---|---|---|---|---|
| pH | 7.41 (7.39; 7.42) | 7.44* (7.42; 7.45) | 7.45*,† (7.43; 7.46) | <0.001 |
| PaCO2, kPa | 5.5 (4.9; 5.9) | 5.0* (4.7; 5.3) | 4.9* (4.6; 5.2) | <0.001 |
| PaO2, kPa | 9.0 (8.4; 9.4) | 8.1* (7.5; 8.6) | 6.8*,† (6.3; 7.4) | <0.001 |
| SaO2, % | 93 (93; 95) | 91* (89; 92) | 85*,† (84; 89) | <0.001 |
| HCO3−, mmol/L | 25.9 (24.5; 27.4) | 25.0 (24.4; 25.5) | 25.6† (25.2; 26.8) | 0.006 |
| Base excess, mmol/L | 1.2 (0.9; 2.1) | 0.7* (0.1; 1.4) | 0.9 (0.3; 1.8) | 0.037 |
| DAaPO2,25 kPa | 4.5 (3.9; 5.4) | 3.4* (2.5; 3.9) | 3.1*,† (2.5; 3.4) | <0.001 |
| Hemoglobin, g/dL | 15.0 (14.5; 15.2) | 14.6 (14.1; 15.2) | 14.8 (14.2; 15.5) | 0.066 |
| Hematocrit, % | 44.5 (43.0; 44.8) | 43.0* (41.0; 44.5) | 43.8† (42.0; 46.0) | 0.015 |
Notes: Median (quartiles), n=32. Arterial blood gases were drawn in the morning after the first night at the corresponding altitude. P-values computed by Friedman ANOVA for overall effects.
*
P<0.05 vs 490 m day 1,
†
P<0.05 vs 1,650 m day 1.
Abbreviation: DAaPO2, Alveolar–arterial PO2 difference.