Validity of arterialised-venous PCO2, pH and bicarbonate in obesity hypoventilation syndrome

This prospective study investigated the validity of arterialised-venous blood gases (AVBG) for estimating arterial carbon dioxide P CO2, pH and bicarbonate (HCO3(-)) in people with obesity hypoventilation syndrome (OHS). AVBGs were obtained from an upper limb vein, after heating the skin at 42-46°C. Arterial blood gas (ABG) and AVBG samples were taken simultaneously and compared using Bland Altman analysis. Between-group differences were assessed with independent t-tests or Mann-Whitney U tests. Forty-two viable paired samples were analysed, including 27 paired samples from 15 OHS participants, and 15 paired samples from 16 controls. AVBG-ABG agreement was not different between groups, or between dorsal hand, forearm and antecubital AVBG sampling sites, and was clinically acceptable for P Co2: mean difference (MD) 0.4 mmHg (0.9%), limits of agreement (LOA) -2.7-3.6 mmHg (± 6.6%); pH: MD -0.008 (-0.1%), LOA -0.023-0.008 (± 0.2%); and HCO3(-): MD -0.3 mmol L(-1) (-1.0%), LOA -1.8-1.2 mmol L(-1) (± 5.3%). AVBG provides valid measures of [Formula: see text] , pH, and HCO3(-) in OHS.