Pulmonary Vascular Congestion: A Mechanism for Distal Lung Unit Dysfunction in Obesity.

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.

Risk factors for and outcomes of detention of patients with TB in New York City: an update: 2002-2009.

BACKGROUND: One of the most controversial aspects of New York City's highly effective TB control program is the use of public health law and court-ordered detention to treat persistently recalcitrant patients with active TB. We now report on characteristics and outcomes of patients undergoing detention for completion of TB treatment due to nonadherence in New York City from 2002 through 2009. METHODS: A retrospective cohort study was designed to compare patients undergoing court-ordered detention (n = 79) and time-matched control subjects undergoing TB treatment in outpatient directly observed therapy (DOT) at Bellevue Hospital in New York City. RESULTS: From January 1, 2002, through December 31, 2009, 79 patients underwent court-ordered detention for TB treatment. Compared with patients completing treatment in DOT, univariate analysis found that detainees were younger; more likely to be of minority race/ethnicity; to have a history of substance abuse, tobacco use, homelessness, incarceration, HIV infection; and to be born in the United States. Multivariate analysis adjusting for other variables found smear positivity (OR = 3.93; 95% CI, 1.05-14.75; P = .04), mental illness (OR = 5.80; 95% CI, 1.18-28.51; P = .03), and substance abuse (OR = 9.25; 95% CI, 2.81-30.39; P < .01) to be the strongest independent predictors of likelihood of detention. Of those initially detained, 46 (58%) completed treatment during inpatient detention, 29(37%) completed treatment under outpatient court-ordered DOT, and four died during their hospitalization. CONCLUSIONS: The majority of patients undergoing court-ordered detention for TB treatment (95%) successfully completed therapy. Likelihood of detention was most strongly associated with factors expected to be associated with poor adherence, including mental illness and substance abuse.