title: Variability of right-sided cardiac oxygen saturations in adults with and without left-to-right intracardiac shunting.
abstract: In many catheterization laboratories and intensive care units, oxygen saturation of single blood specimens is measured from the superior vena cava (SVC), right atrium (RA) and pulmonary artery (PA) during right-sided catheterization, but variability of such single measurements in adults with and without intracardiac left-to-right shunting has not been assessed. Oxygen saturation of SVC, RA and PA single blood samples were measured in 1,031 adults (524 men, 507 women, aged 50 +/- 13 years [mean +/- standard deviation SD]). In the 980 patients without shunting, differences in saturation between SVC and RA, RA and PA and SVC and PA were 3.9 +/- 2.4%, 2.3 +/- 1.7%, and 4.0 +/- 2.5%, respectively, so that the normal limits of variability (mean +/- 2 standard deviations) for these saturation differences were 8.7%, 5.7% and 9.0%, respectively. Of the 51 patients with left-to-right shunting, these limits of variability of oxygen saturation correctly identified 46 (90%), and the 5 with shunting whose saturation differences were below these limits had small shunts (Qp/Qs ratios of 1.9 or less). Thus, assessment of oxygen saturation from single blood specimens obtained from the SVC, RA and PA offers excellent sensitivity (more than 90%), specificity (94 to 95%) and predictive accuracy (94% or more) in identifying patients with and without intracardiac left-to-right shunting. The sensitivity of these limits is especially high in patients with large shunts (Qp/Qs of 2 or more).
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006325:Heart Atria; D006343:Heart Septal Defects / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods; D010100:Oxygen / Q000097:blood*; D011651:Pulmonary Artery; D014683:Vena Cava, Superior
chemical_list: D010100:Oxygen