Table 3.
Ventilatory Responses to Inspired Gas Mixtures Before and After CPAP Therapy
| Gas mixture | N | ΔPETCO2 |
ΔO2Sat |
Dynamic Response |
Dynamic Response (%) |
||||
|---|---|---|---|---|---|---|---|---|---|
| Pre-CPAP | Post-CPAP | Pre-CPAP | Post-CPAP | Pre-CPAP | Post-CPAP | Pre-CPAP | Post-CPAP | ||
| 2% CO2 | 6 | 5.4 (2.0) | 4.2 (3.1) | 0.0 (0.8) | 0.2 (0.6) | 3.7 (1.5) | 2.4 (1.2)* | 47 (15) | 28 (15)* |
| 3% CO2 | 14 | 7.8 (2.5) | 7.1 (1.8) | 0.0 (1.0) | −0.9 (1.1)* | 3.8 (2.2) | 2.2 (1.3)*** | 54 (27) | 28 (13)*** |
| 6% CO2 | 15 | 14.2 (2.8) | 12.8 (2.8) | 0.2 (1.1) | −0.5 (0.7)* | 5.6 (3.5) | 4.1 (2.1)* | 80 (50) | 53 (26)** |
| 1% CO2 in (11-15)%O2 | 14 | 1.6 (1.4) | 2.0 (1.9) | −5.2 (2.3) | −7.0 (3.5) | 3.2 (2.2) | 1.6 (1.7)*** | 48 (35) | 22 (23)*** |
| 3% CO2 in (11-15)%O2 | 14 | 5.5 (2.3) | 5.3 (2.3) | −4.4 (1.8) | −5.0 (1.5) | 7.7 (4.8) | 3.8 (2.9)*** | 131 (95) | 52 (34)*** |
Values in brackets are standard deviation; ΔPETCO2, change in end-tidal PCO2 during the gas challenge; O2Sat, change in oxyhemoglobin saturation during the gas challenge; Dynamic Response, change in minute ventilation at breath 5 relative to baseline; Dynamic Response(%),Dynamic Response as % baseline. Numbers in brackets are SD.
*
P < 0.05;
**
P < 0.01;
***
P < 0.005 for differences between pre- and post-CPAP therapy.