tokens: The mean ( + / - SD ) PaO2 increased from 80 . 8 + / - 26 . 9 mmHg before to 89 . 8 + / - 27 . 3 mmHg after the infusion ( P < 0 . 05 ) and the PaCO2 decreased from 42 . 4 + / - 8 . 3 to 39 . 6 + / - 7 . 9 mmHg ( P < 0 . 05 ) .