Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Aug 1;178(3):295-9.
doi: 10.1164/rccm.200801-113OC. Epub 2008 May 1.

Hypoxemia in inferior pulmonary veins in supine position is dependent on obesity

Affiliations

Hypoxemia in inferior pulmonary veins in supine position is dependent on obesity

Teiichi Yamane et al. Am J Respir Crit Care Med. .

Abstract

Rationale: Although arterial oxygen concentration decreases in obese subjects, the mechanism for this remains to be determined.

Objectives: The blood gas level in each pulmonary vein (PV) was measured in supine subjects with diverse body mass index (BMI) values, to determine whether there was a regional insufficiency in gas exchange depending on the subject's BMI.

Methods: Forty subjects with normal cardiopulmonary function who underwent a catheter ablation for atrial fibrillation were included. Before delivering any radiofrequency energy application, blood samples were obtained from each of the four PVs during physiologic breathing in a supine position to measure the PO2 and PCO2 values. Spirometry and ventilation/perfusion lung scintigraphy were also performed.

Measurements and main results: The PO2 value was significantly higher in superior veins than inferior veins (91.8 +/- 13.5, 70.8 +/- 16.3, 92.2 +/- 11.1, and 73.6 +/- 13.7 mm Hg, in the left superior, left inferior, right superior, and right inferior PV, respectively). There was a significant inverse relationship between the PO2 and PCO2 values. Neither the spirometry nor lung scintigraphy could detect any remarkable findings corresponding to the low PO2 values. Among the various clinical characteristics, only the BMI was significantly associated with the decreased PO2 value in the inferior veins.

Conclusions: Hypoxia in obese subjects in a supine position is thus considered to be primarily caused by insufficient gas exchange in the regions of lung linked to the inferior PVs. The inverse relationship between the BMI and PO2 value in the inferior PVs suggests a possible subclinical manifestation of obesity-related respiratory insufficiency.

PubMed Disclaimer