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BACKGROUND: Pattern of flow-volume (F-V) loop in unilateral main bronchus obstruction (UMBO) is under-represented and sometimes misinterpreted as chronic obstructive pulmonary disease (COPD). METHODS: A cross-sectional study was performed among patients with UMBO and COPD confirmed by bronchoscopy, radiographic imaging and spirometry from 2006 to 2019. Data were extracted from electronic medical records. Spirometry data and flow-volume curves (F-V curves) were analyzed. Expiratory F-V curve was classified as monophasic or biphasic according to the absence or presence of breakpoint separating two distinct slopes. Propensity score method was used to reduce the selection bias, and logistic analysis in combination with decision tree approach was performed to explore the differences among groups. RESULTS: Fifty-six patients with UMBO, 121 individuals with COPD and 68 healthy subjects were included. Typical biphasic expiratory F-V curve was observed in 57.1% in UMBO group, especially of grade II (stenosis was 51–90%), and in 46.3% in COPD group, while biphasic inspiratory curve presented in 7.1% of UMBO, and none in COPD. In UMBO, breakpoints tended to appear gradually and smoothly between MEF(75) and MEF50, whereas in COPD they often occurred abruptly and rigidly, ahead of MEF(75). CONCLUSIONS: The characteristics of F-V curve, apart from biphasic pattern, the location and configuration of breakpoint in expiratory curve, seemed to be important features of UMBO, which might help to differentiate them from COPD. More data is needed to validate these findings.

Background Chronic obstructive pulmonary disease (COPD) has become a major public-health problem in China. Surfactant protein D (SP-D) is a very promising biomarker and therapeutic target for COPD. To assess whether baseline serum SP-D is associated with lung function decline and incident COPD. Methods This longitudinal study was initiated in 2009 in a community in Beijing. Data were collected on spirometry, and the baseline level of serum SP-D was measured in 772 non-COPD subjects aged 40-70 years old. In 2012, spirometry was repeated in 364 individuals, 37 of whom subjects had incident COPD. Results From 2009 to 2012, subjects with incident COPD had a more rapid decline in FEV1 (MD 98.27 vs. MD 43.41 mL) compared with those without COPD. There was no association between baseline serum SP-D and the COPD incidence. Smoking (OR =2.72; P=0.002) and age (OR =1.06; P=0.000) were risk factors for COPD. The rate of FEV1 decline varies widely in the general population, and the univariate analysis showed that baseline serum SP-D levels (R=-0.169; P=0.003), income level, home-road distance, and statin use were inversely correlated with the decline in FEV1. After multivariable analyses, only smoking was consistently associated with the decline in FEV1. Conclusions There was no correlation between baseline serum SP-D levels and incident COPD in a general population. Smoking and age were major risk factors for COPD. The effect of serum SP-D levels on the decline in FEV1 needs further investigation.

Background: Evaluation and location of the approaches is the key step of medical thoracoscopy. The previous standard for the step in many countries is artificial pneumothorax (AP). Recently, thoracic ultrasound (TU) has been considered as one of the choices for the development of technology. While there was a lack of data in investigating the complications of medical thoracoscopy locating approach with AP comparing TU. Methods: A total of 108 patients who underwent medical thoracoscopy were retrospectively observed in Peking University First Hospital from January 2011 to April 2017, including 92 patients of the AP group and 16 patients of the TU group. Propensity score matching (PSM) was used to balance the covariance between the two groups. And the complications of the procedures between the groups were compared. Results: Before PSM, there was one unbalanced covariates in the two groups. The overall complication rate was 7.6% (7/92) in the AP group, comparing 6.2% (1/16) in the TU group. There was no significant difference between the two groups (P=0.848). After balancing the covariate with 2:1 matched, the overall complication rate was 9.4% (3/32) in the AP group, comparing 6.2% (1/16) in the TU group. There was still no significant difference between the two groups (P=0.712). Conclusions: TU is a locating approach method which does not increase the complication rate comparing with AP. And it could be a good choice in medical thoracoscopy.

Bronchial thermoplasty (BT) is a non-pharmacologic therapy for severe asthma. The proper procedure and perioperative management are very important for the effectiveness and safety of BT. China Asthma Alliance assembled a group of experts in asthma and BT to review the literature, drew on their own experiences, discussed, and then finalized by consensus to establish this standard practice guideline. This practice guideline is designed to guide clinicians as to proper patients’ selection, preoperative assessment, postoperative management and follow-up. This practice guideline also proposed “China Alair System Registry Study (NCT02206269)” as the real-world study to enhance clinical utility of BT.

Fine particulate exposure (PM2.5) is a risk factor of pulmonary diseases such as chronic obstructive pulmonary disease (COPD), but the mechanism underlying was not clear. Recent studies found blood microRNAs (miRNAs) are potential indicators of either COPD or PM2.5 exposure, but these results had no unified conclusions. We suggested it was more targeted to find disease related miRNAs first and then observe them during PM2.5 exposure. Firstly, in order to screen COPD associated miRNAs, we identified differentially expressed blood miRNAs contrasting COPD participants (n=6) without diagnose of COPD or related treatment before and matched control (n=6). In total, 21 miRNAs were differentially expressed in COPD individuals and expression of miR-495-3p, miR-223-5p and miR-194-3p were further validated using qRT-PCR. The results showed miR-495-3p and miR-223-5p significantly increased whereas miR-194-3p decreased marginally (P=0.058) in COPD participants. Secondly, in order to recognize the relevance between these miRNAs and PM2.5 exposure, we designed an independent time-series study nested within "low-high-low" pollution levels. The expression of blood miR-495-3p, miR-223-5p and miR-194-3p were detected before and after exposure (n=8). The results showed expression of miR-223-5p increased significantly while expression of miR-194-3p decreased significantly after exposure. The Pearson analysis showed only miR-194-3p showed a positive statistically correlation with lag0-1 forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) during exposure of PM2.5. So miR-194-3p might be a potential regulator in the toxicological pathways of both PM2.5 exposure and COPD. As this was a pilot study, formal and large-scale studies should be planned in the future.