FiO2 0.28 | FiO2 0.50 | |||||
---|---|---|---|---|---|---|
Room air baseline | 20 min | Adj. p value | Room air baseline | 20 min | Adj. p value | |
OHS group | ||||||
SpO2 (%) | 94±3 | 99±1 | – | 94±3 | 100±0 | – |
PavCO2 (kPa) | 7.1±0.6 | 7.4±0.6 | 0.013 | 7.2±0.6 | 7.7±1.0 | 0.012 |
pH | 7.371±0.019 | 7.359±0.027 | 0.406* | 7.373±0.021 | 7.346±0.030 | 0.011 |
VE (L/min) | 9.9±2.3 | 9.9±2.8 | 0.997 | 9.6±2.1 | 9.3±2.9 | 0.224* |
VD/VT (ratio) | 0.28±0.05 | 0.29±0.03 | 0.012 | 0.29±0.05 | 0.32±0.05 | 0.012 |
VDphys (mL) | 200±55 | 196±26 | >0.999 | 194±56 | 192±37 | >0.999 |
VT (mL) | 633±149 | 597±129 | 0.012 | 578±105 | 489±107 | 0.012 |
RR (br/min) | 17.5±5.2 | 18.2±4.7 | >0.999 | 18.1±4.9 | 18.1±4.2 | >0.999 |
Control group | ||||||
SpO2 (%) | 98±1 | 100±1 | – | 98±1 | 100±0 | – |
PavCO2 (kPa) | 5.5±0.4 | 5.6±0.2 | 0.726 | 5.4±0.3 | 5.4±0.4 | >0.999 |
pH | 7.408±0.023 | 7.397±0.010 | >0.999 | 7.407±0.020 | 7.407±0.023 | >0.999 |
VE (L/min) | 7.5±1.6 | 7.5±1.7 | >0.999 | 7.6±1.8 | 8.6±1.9 | 0.019 |
VD/VT (ratio) | 0.27±0.05 | 0.29±0.04 | 0.012 | 0.28±0.04 | 0.32±0.04 | 0.012 |
VDphys (mL) | 232±79 | 237±53 | 0.085* | 244±123 | 263±97 | 0.085* |
VT (mL) | 813 (353) | 754 (356) | >0.999 | 751 (285) | 751 (264) | >0.999 |
RR (br/min) | 10.3±4.2 | 10.5±4.5 | 0.195* | 10.6±3.7 | 11.8±3.6 | 0.195* |
Data presented as mean±SD or median (IQR).
Adj. p value: significance level from general linear model analysis, change over time (ie room air vs oxygen) after Holm's Bonferroni correction (refer to table E1, online supplement for full details).
*Raw p value significant but adj. p value=non-significant.
FiO2, inspired oxygen fraction; PavCO2, arterialised-venous carbon dioxide; RR, respiratory rate; SpO2, pulse oxygen saturation; VD/VT, physiological dead space to tidal volume ratio; VDphys, physiological dead space; VE, minute ventilation; VT, tidal volume.