Mechanisms of Orthopnea in Stable Obese Subjects.

BACKGROUND: The present study explored the role of closing volume as a determinant of orthopnea in stable obese subjects. We hypothesized that: (1) increase in closing volume in supine position would be greater in orthopneic than in non-orthopneic subjects, and (2) the relationship of change in closing volume to change in dyspnea with position would be dependent on expiratory flow limitation in the sitting position. METHODS: In stable obese subjects, in sitting and supine positions, we measured the Borg dyspnea score, static lung volumes, expiratory flow limitation during tidal breathing, and single-breath nitrogen expiration test. From the latter, we determined closing volume and closing capacity, slope of phase III, and opening capacity. Orthopnea was defined as any increase in the Borg score in the supine position from its value in the sitting position. RESULTS: Twenty-one subjects (13 women), median age (interquartile range) 55 (49-57) y and with body mass index of 39 (38-42) kg/m(2) were included, of whom 12 were orthopneic and 11 had expiratory flow limitation while seated. In the sitting position, orthopneic and non-orthopneic subjects were similar for age, body mass index, and pulmonary function tests, including single-breath nitrogen expiration test-derived variables. In the orthopneic subjects, there were no changes in any respiratory variable between positions. In the non-orthopneic subjects, there was a significant decrease in slope of phase III in the supine position from 1.67 (1.33-3.60) to 1.40 (1.25-1.66)%/L (P = .008). Overall, the subjects' Borg score significantly correlated with the slope of phase III (r = 0.63, P = .002) and opening capacity (r = -0.47, P = .03). In 10 subjects without expiratory flow limitation, it correlated with slope of phase III (r = 0.68, P = .03). CONCLUSIONS: In stable obese subjects, magnitude of orthopnea correlated with an increase in the slope of phase III in subjects without expiratory flow limitation. Expiratory flow limitation should be taken into account in obese patients.

Lung cancer may increase serum procalcitonin level.

INTRODUCTION: Serum procalcitonin (PCT) is a biomarker used routinely to diagnose infections. Some malignancies are usual false positives for PCT. However, its value and behavior in the setting of lung cancers are poorly known. The objective of this study was to assess PCT positivity in a lung cancer cases series. METHOD: Between November 2011 and September 2012, all cases of newly diagnosed lung cancer with a pre-antineoplastic PCT assay and no patent signs of infection were included in the study. All PCT levels were assessed by immunofluorescent assay in a single laboratory. RESULTS: Eighty-nine patients were included (70.8% male; mean age 62; small-cell cancer 20.2%; stage IV cancer 60.7%). Overall, PCT was positive in 42%. A neuroendocrine component, having 2 or more metastatic sites, having a pleura or a liver metastasis, and being positive for CRP were all significantly associated with positive PCT in univariate analysis. In multivariate analysis, only the presence of a neuroendocrine component remained strongly associated with a positive PCT (AOR=7.24 [CI=95% 1.91-27.51]; P=0.004). Finally, baseline PCT levels <0.5 µg/l were found in 43% of NSCLC with a neuroendocrine component, vs. 9% of cancers with other histology (P=0.0001). CONCLUSION: Lung cancer may cause false positives for procalcitonin, particularly in cases of neuroendocrine cancers or in the presence of multiple metastases. These results should be taken into account for PCT-based decisional algorithms.