TY - JOUR
T1 - Pulmonary Vascular Congestion
T2 - A Mechanism for Distal Lung Unit Dysfunction in Obesity
AU - Oppenheimer, Beno W.
AU - Berger, Kenneth I.
AU - Ali, Saleem
AU - Segal, Leopoldo N.
AU - Donnino, Robert
AU - Katz, Stuart
AU - Parikh, Manish
AU - Goldring, Roberta M.
PY - 2016/4/1
Y1 - 2016/4/1
N2 - Rationale Obesity is characterized by increased systemic and pulmonary blood volumes (pulmonary vascular congestion). Concomitant abnormal alveolar membrane diffusion suggests subclinical interstitial edema. In this setting, functional abnormalities should encompass the entire distal lung including the airways. Objectives We hypothesize that in obesity: 1) pulmonary vascular congestion will affect the distal lung unit with concordant alveolar membrane and distal airway abnormalities; and 2) the degree of pulmonary congestion and membrane dysfunction will relate to the cardiac response. Methods 54 non-smoking obese subjects underwent spirometry, impulse oscillometry (IOS), diffusion capacity (DLCO ) with partition into membrane diffusion (DM ) and capillary blood volume (VC ), and cardiac MRI (n = 24). Alveolar-capillary membrane efficiency was assessed by calculation of DM/VC . Measurements and Main Results Mean age was 45±12 years; mean BMI was 44.8±7 kg/m2 . Vital capacity was 88±13% predicted with reduction in functional residual capacity (58±12% predicted). Despite normal DLCO (98±18% predicted), VC was elevated (135±31% predicted) while DM averaged 94 ±22% predicted. DM /VC varied from 0.4 to 1.4 with high values reflecting recruitment of alveolar membrane and low values indicating alveolar membrane dysfunction. The most abnormal IOS (R5 and X5 ) occurred in subjects with lowest DM /VC (r2 = 0.31, p<0.001; r2 = 0.34, p<0.001). Cardiac output and index (cardiac output / body surface area) were directly related to DM /VC (r2 = 0.41, p<0.001; r2 = 0.19, p = 0.03). Subjects with lower DM /VC demonstrated a cardiac output that remained in the normal range despite presence of obesity. Conclusions Global dysfunction of the distal lung (alveolar membrane and distal airway) is associated with pulmonary vascular congestion and failure to achieve the high output state of obesity. Pulmonary vascular congestion and consequent fluid transudation and/or alterations in the structure of the alveolar capillary membrane may be considered often unrecognized causes of airway dysfunction in obesity.
AB - Rationale Obesity is characterized by increased systemic and pulmonary blood volumes (pulmonary vascular congestion). Concomitant abnormal alveolar membrane diffusion suggests subclinical interstitial edema. In this setting, functional abnormalities should encompass the entire distal lung including the airways. Objectives We hypothesize that in obesity: 1) pulmonary vascular congestion will affect the distal lung unit with concordant alveolar membrane and distal airway abnormalities; and 2) the degree of pulmonary congestion and membrane dysfunction will relate to the cardiac response. Methods 54 non-smoking obese subjects underwent spirometry, impulse oscillometry (IOS), diffusion capacity (DLCO ) with partition into membrane diffusion (DM ) and capillary blood volume (VC ), and cardiac MRI (n = 24). Alveolar-capillary membrane efficiency was assessed by calculation of DM/VC . Measurements and Main Results Mean age was 45±12 years; mean BMI was 44.8±7 kg/m2 . Vital capacity was 88±13% predicted with reduction in functional residual capacity (58±12% predicted). Despite normal DLCO (98±18% predicted), VC was elevated (135±31% predicted) while DM averaged 94 ±22% predicted. DM /VC varied from 0.4 to 1.4 with high values reflecting recruitment of alveolar membrane and low values indicating alveolar membrane dysfunction. The most abnormal IOS (R5 and X5 ) occurred in subjects with lowest DM /VC (r2 = 0.31, p<0.001; r2 = 0.34, p<0.001). Cardiac output and index (cardiac output / body surface area) were directly related to DM /VC (r2 = 0.41, p<0.001; r2 = 0.19, p = 0.03). Subjects with lower DM /VC demonstrated a cardiac output that remained in the normal range despite presence of obesity. Conclusions Global dysfunction of the distal lung (alveolar membrane and distal airway) is associated with pulmonary vascular congestion and failure to achieve the high output state of obesity. Pulmonary vascular congestion and consequent fluid transudation and/or alterations in the structure of the alveolar capillary membrane may be considered often unrecognized causes of airway dysfunction in obesity.
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U2 - 10.1371/journal.pone.0152769
DO - 10.1371/journal.pone.0152769
M3 - Article
C2 - 27035663
AN - SCOPUS:84963876989
SN - 1932-6203
VL - 11
JO - PloS one
JF - PloS one
IS - 4
M1 - e0152769
ER -