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Effect of Circulatory Congestion on the Components of Pulmonary Diffusing Capacity in Morbid Obesity
Author(s) -
Oppenheimer Beno W.,
Berger Kenneth I.,
Rennert Douglas A.,
Pierson Richard N.,
Norman Robert G.,
Rapoport David M.,
Kral John G.,
Goldring Roberta M.
Publication year - 2006
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2006.134
Subject(s) - circulatory system , pulmonary diffusing capacity , medicine , cardiology , weight loss , obesity , diffusing capacity , lung , lung function
Objective: Obese patients without clinically apparent heart disease may have a high output state and elevated total and central blood volumes. Central circulatory congestion should result in elevated pulmonary diffusing capacity (D LCO ) and capillary blood volume (V c ) reflecting pulmonary capillary recruitment; however, the effect on membrane diffusion (D m ) is uncertain. We examined D LCO and its partition into V c and D m in 13 severely obese subjects (BMI = 51 ± 14 kg/m 2 ) without manifest cardiopulmonary disease before and after surgically induced weight loss. Research Methods and Procedures: D LCO and its partition into V c and D m [referenced to alveolar volume (V A )] as described by Roughton and Forster, total body water by tritiated water, and fat distribution by waist‐to‐hip ratio were performed. Results: Despite normal D LCO (mean 98 ± 16% predicted), V c /V A was increased (mean 118 ± 30% predicted), and D m /V A was reduced (mean 77 ± 34% predicted). Nine of 13 subjects were restudied after weight loss (mean 52 ± 43 kg); V c /V A decreased to 89 ± 18% predicted ( p = 0.01), and D m /V A increased to 139 ± 30% predicted ( p < 0.01). Increasing total body water was associated with both increasing V c ( r = 0.74, p = 0.01) and increasing waist‐to‐hip ratio ( r = 0.65, p = 0.02), indicating that circulatory congestion increases with increasing central obesity. Discussion: Severely obese subjects without manifest cardiopulmonary disease may have increased V c indicating central circulatory congestion and reduced D m suggesting associated alveolar capillary leak, despite normal D LCO . Reversibility with weight loss is in accord with reversibility of the hemodynamic abnormalities of obesity.