Table 1.
Pulmonary gas exchange and haemodynamics
| Location: | SL | HA-3h | HA-20h | |||
|---|---|---|---|---|---|---|
| Sample site | Radial arterial | Central venous | Radial arterial | Central venous | Radial arterial | Central venous |
 (mmHg) |
95 ± 11 | 38 ± 5* | 38 ± 3† | 28 ± 2*† | 41 ± 4†‡ | 29 ± 3*† |
| Main effects (P < 0.05): HA < SL + Arterial > Venous; interaction effect (P < 0.05) | ||||||
 (mmHg) |
40 ± 3 | 48 ± 4* | 29 ± 3† | 33 ± 4*† | 28 ± 2† | 32 ± 2*† |
| Main effects (P < 0.05): HA < SL + Arterial < Venous; interaction effect (P < 0.05) | ||||||
 (%) |
97 ± 1 | 70 ± 6* | 72 ± 5† | 52 ± 5*† | 74 ± 5† | 50 ± 6*† |
| Main effects (P < 0.05): HA < SL + Arterial > Venous; interaction effect (P < 0.05) | ||||||
| pH (units) | 7.41 ± 0.03 | 7.36 ± 0.01* | 7.48 ± 0.02† | 7.46 ± 0.02*† | 7.47 ± 0.02†‡ | 7.44 ± 0.02*†‡ |
| Main effects (P < 0.05): HA > SL + Arterial > Venous; interaction effect (P < 0.05) | ||||||
| [A-a]O2diff (mmHg) | 13 ± 7 | 10 ± 4 | 9 ± 5 | |||
| PBF (l min−1) | 6.4 ± 1.4 | 6.9 ± 1.2 | 6.2 ± 1.0‡ | |||
| PPF (l min−1) | 3.7 ± 0.8 | 3.9 ± 0.7 | 3.5 ± 0.5‡ | |||
| PASP (mmHg) | 23 ± 4 | 39 ± 10† | 38 ± 10† | |||
Values are means ±s.d.; SL, sea level; HA, high-altitude; 
/
partial pressure of oxygen/carbon dioxide; 
, oxyhaemoglobin saturation; [A-a]O2diff, alveolar to arterial 
difference; PBF/PPF, pulmonary blood/plasma flow; PASP, pulmonary artery systolic pressure.
*
P < 0.05 vs. radial arterial for given location
†
P < 0.05 vs. SL for given sample site
‡
P < 0.05 vs. HA-3h for given sample site.