Table 2.
Effect of inhalation of different mixtures of O2 and CO2 on systemic pH, pCO2, and pO2 (n=12; means (SD)) on both study days
| RVA, study day | LDV, study day | |||
| Baseline | End of breathing period | Baseline | End of breathing period | |
| pH | ||||
| 100% O2 | 7.38 (0.02) | 7.39 (0.03) | 7.35 (0.08) | 7.37 (0.09)† |
| 97.5% O2 + 2.5% CO2 | 7.38 (0.03) | 7.37 (0.03)* | 7.34 (0.09) | 7.33 (0.09)* |
| 95% O2 + 5% CO2 | 7.38 (0.02) | 7.34 (0.02)*† | 7.36 (0.07) | 7.32 (0.08)*† |
| 92% O2 + 8% CO2 | 7.38 (0.02) | 7.27 (0.04)*† | 7.34 (0.07) | 7.23 (0.09)*† |
| pCO2 | ||||
| 100% O2 | 40 (2) | 38 (2)† | 40 (2) | 37 (2)† |
| 97.5% O2 + 2.5% CO2 | 40 (3) | 42 (2)* | 40 (3) | 41 (2)* |
| 95% O2 + 5% CO2 | 40 (2) | 46 (3)*† | 40 (6) | 45 (6)*† |
| 92% O2 + 8% CO2 | 40 (2) | 55 (7)*† | 40 (3) | 58 (5)*† |
| pO2 | ||||
| 100% O2 | 85 (7) | 425 (69)† | 85 (7) | 413 (92)† |
| 97.5% O2 + 2.5% CO2 | 86 (7) | 390 (96)† | 84 (8) | 386 (111)† |
| 95% O2 + 5% CO2 | 86 (6) | 413 (98)† | 87 (10) | 414 (101)† |
| 92% O2 + 8% CO2 | 85 (6) | 406 (102)† | 88 (9) | 443 (53)† |
*p<0.05 versus 100% O2; †p<0.05 versus baseline.