Table 1

ABG parameters of the patient in the sitting and recumbent position

Parameters	Sitting position, room air^#	Recumbent position, room air^¶
pH	7.477	7.402
P_aCO₂	23.2 mmHg	23.7 mmHg
P_aO₂	50.5 mmHg	60.6 mmHg
S_aO₂	83.3%	90.2%
HCO₃⁻	17.3 mmol·L⁻¹	17.1 mmol·L⁻¹
Alveolar–arterial gradient	70.2 mmHg	59.5 mmHg

P_aCO₂: arterial carbon dioxide tension; S_aO₂: arterial oxygen saturation; HCO₃⁻: bicarbonate ion concentration; S_pO₂: oxygen saturation measured by pulse oximeter; F_IO₂: inspiratory oxygen fraction. ^#: S_pO₂ 84%, heart rate 113 beats per min, P_aO₂/F_IO₂ 240; ^¶: S_pO₂ 93%, heart rate 79 beats per min, P_aO₂/F_IO₂ 314.