Disease 2019 (COVID-19) as a pandemic. As of 22 April, more than 2.4 million cases have been confirmed worldwide 1 . In light of the widely documented lung injuries related with COVID-19 2-3 , concerns are raised regarding the assessment of the lung injury for discharged patients. A recent report portrayed that discharged patients with COVID-19 pneumonia are still having residual abnormalities in chest CT scans, with ground-glass opacity as the most common pattern 4 . Persistent impairment of pulmonary function and exercise capacity have been known to last for months or even years [5][6][7][8] in the recovered survivors with other coronavirus pneumonia (severe acute respiratory syndrome/SARS and middle east respiratory syndrome/MERS). However, until now, there is no report in regard to pulmonary function in discharged COVID-19 survivors. Our manuscript aims to describe the characteristics of pulmonary function in these subjects.We recruited laboratory confirmed non-critical COVID-19 cases, from February 5th to March 17th from admitted patients. According to the WHO interim guidance 9 and the guidance from china 10 , disease severity were categorized as mild illness(mild symptoms without radiographic appearance of pneumonia), pneumonia(having symptoms and the radiographic evidence of pneumonia, with no requirement for supplemental oxygen), severe pneumonia(having pneumonia, including one of the following: respiratory rate > 30 breaths/minute; severe respiratory distress; or SpO2 ≤ 93% on room air at rest), and critical cases (e.g. respiratory failure requiring mechanical ventilation, Septic shock, other organ failure occurrence or admission into the ICU). Critical cases were excluded from our study.Spirometry and pulmonary diffusion capacity test (Cosmed PFT Quark, Rome, Italy) were performed following the ATS-ERS guidelines on the day of or one day before discharge. To minimize cross infections, carbon monoxide diffusion capacity (DLCO) was measured by the single-breath method. Written informed consent was obtained from all patients, and the study was approved by the ethics committee of The Guangzhou Eighth People's Hospital.One-hundred and ten discharged cases were recruited, which included 24 cases of mild illness, 67 cases of pneumonia and 19 cases of severe pneumonia (Table 1). The mean age of these cases was 49.1 years and fifty-five of them were females. Forty-four (40%) patients had at least one underlying comorbidity, of which 23.6% had hypertension and 8.2% had diabetes. Only 3 patients (2.7%) were reported having chronic respiratory diseases (one patient with asthma, one with chronic bronchitis and one with bronchiectasis). No significant differences were found among the three groups of cases, in the relation to gender, smoking status, underlying disease and the BMI value. The duration from onset of disease to pulmonary function test was 20±6 days in cases with mild illness, 29±8 days in cases with pneumonia and 34±7 days in cases that presented severe pneumonia. On the day of discharge, the SpO2% on ro...

Postintubation tracheal stenosis is a complication of endotracheal intubation. The pathological mechanism and risk factors for endotracheal intubation-induced tracheal stenosis remain not fully understood. We aimed to establish an animal model and to investigate risk factors for postintubation tracheal stenosis. Beagles were intubated with 4 sized tubes (internal diameter 6.5 to 8.0 mm) and cuff pressures of 100 to 200 mmHg for 24 hr. The status of tracheal wall was evaluated by bronchoscopic and histological examinations. The model was successfully established by cuffed endotracheal intubation using an 8.0 mm tube and an intra-cuff pressure of 200 mmHg for 24 hr. When the intra-cuff pressures were kept constant, a larger sized tube would induce a larger tracheal wall pressure and more severe injury to the tracheal wall. The degree of tracheal stenosis ranged from 78% to 91% at 2 weeks postextubation. Histological examination demonstrated submucosal infiltration of inflammatory cells, hyperplasia of granulation tissue and collapse of tracheal cartilage. In summary, a novel animal model of tracheal stenosis was established by cuffed endotracheal intubation, whose histopathological feathers are similar to those of clinical cases of postintubation tracheal stenosis. Excessive cuff pressure and over-sized tube are the risk factors for postintubation tracheal stenosis.

BackgroundSpirometry confers limited value for identifying small-airway disorders (SADs) in early-stage COPD, which can be detected with impulse oscillometry (IOS) and endobronchial optical coherence tomography (EB-OCT). Whether IOS is useful for reflecting small-airway morphological abnormalities in COPD remains unclear.ObjectivesTo compare the diagnostic value of spirometry and IOS for identifying SADs in heavy-smokers and COPD based on the objective assessment with EB-OCT.MethodsWe recruited 59 COPD patients (stage I, n=17; stage II, n=18; stage III–IV, n=24), 26 heavy-smokers and 21 never-smokers. Assessments of clinical characteristics, spirometry, IOS and EB-OCT were performed. Receiver operation characteristic curve was employed to demonstrate the diagnostic value of IOS and spirometric parameters.ResultsMore advanced staging of COPD was associated with greater abnormality of IOS and spirometric parameters. Resonant frequency (Fres) and peripheral airway resistance (R5–R20) conferred greater diagnostic values than forced expiratory volume in one second (FEV1%) and maximal (mid-)expiratory flow (MMEF%) predicted in discriminating SADs in never-smokers from heavy-smokers (area under curve [AUC]: 0.771 and 0.753 vs 0.570 and 0.558, respectively), and heavy-smokers from patients with stage I COPD (AUC: 0.726 and 0.633 vs 0.548 and 0.567, respectively). The combination of IOS (Fres and R5–R20) and spirometric parameters (FEV1% and MMEF% predicted) contributed to a further increase in the diagnostic value for identifying SADs in early-stage COPD. Small airway wall area percentage (Aw% 7–9), an EB-OCT parameter, correlated significantly with Fres and R5–R20 in COPD and heavy-smokers, whereas EB-OCT parameters correlated with FEV1% and MMEF% in advanced, rather than early-stage, COPD.ConclusionsIOS parameters correlated with the degree of morphologic abnormalities of small airways assessed with EB-OCT in COPD and heavy-smokers. Fres and R5–R20 might be sensitive parameters that reliably reflect SADs in heavy-smokers and early-stage COPD.

Background: Patients with pulmonary tuberculosis (PTB) have a high risk of concomitant tracheobronchial tuberculosis (TBTB), which commonly causes severe complications such as tracheobronchial stenosis. The prevalence and predictors of TBTB in China remain unclear due to the lack of prospective and large-scale studies. Objectives: To investigate the incidence of TBTB in PTB patients in southern China, and elucidate the predictors of TBTB and related tracheobronchial stenosis. Methods: We prospectively performed bronchoscopy in PTB patients to diagnose TBTB at four medical centres in southern China from September 2015 to August 2016. Clinical and epidemiological data were recorded and analysed to determine predictors of TBTB and related tracheobronchial stenosis. Results: A total of 345 (23.9%) of the 1,442 PTB patients undergoing bronchoscopy were diagnosed with TBTB. Female sex (OR 2.53), age < 50 years (OR 1.88), living in urban (OR 2.19), diabetes (OR 1.84), coughing (OR 2.61), and symptoms ≥4 weeks (OR 1.66) were predictors of PTB concomitant with TBTB. About 59.7% TBTB patients developed tracheobronchial stenosis, of which 23.3% cases presented severe airway narrowing. Female sex (OR 2.27), age < 50 years (OR 2.11), shortness of breath (OR 1.97), and symptoms ≥4 weeks (OR 1.71) were predictors of TBTB-related tracheobronchial stenosis. Conclusions: About 23.9% of PTB patients undergoing bronchoscopy present with TBTB in Guangdong province, southern China. Young and middle-aged females with symptoms persisting for ≥4 weeks (the main predictors of TBTB and related tracheobronchial stenosis) should receive bronchoscopy immediately when diagnosed with PTB.

Background: Hydrogen-oxygen mixture (H₂-O₂) may reduce airway resistance in patients with acute severe tracheal stenosis, yet data supporting the clinical use of H₂-O₂ are insufficient. Objectives: To evaluate the efficacy and safety of breathing H₂-O₂ in acute severe tracheal stenosis. Methods: Thirty-five consecutive patients with severe acute tracheal stenosis were recruited in this prospective self-control study. Air, H₂-O₂ and O₂ inhalation was given in 4 consecutive breathing steps: air for 15 min, H₂-O₂ (6 L per min, H₂:O₂ = 2: 1) for 15 min, oxygen (3 L per min) for 15 min, and H₂-O₂ for 120 min. The primary endpoint was inspiratory effort as assessed by diaphragm electromyography (EMGdi); the secondary endpoints were transdiaphragmatic pressure (Pdi), Borg score, vital signs, and impulse oscillometry (IOS). The concentration of H₂ in the ambient environment was obtained with 12 monitors. Adverse reactions during the inhalation were recorded. Results: The mean reduction in the EMGdi under H₂-O₂ was 10.53 ± 6.83%. The EMGdi significantly decreased during 2 H₂-O₂ inhalation steps (Steps 2 and 4) compared with air (Step 1) and O₂ (Step 3) (52.95 ± 15.00 vs. 42.46 ± 13.90 vs. 53.20 ± 14.74 vs. 42.50 ± 14.12% for Steps 1 through 4, p < 0.05). The mean reduction in the Pdi under H₂-O₂ was 4.77 ± 3.51 cmH₂O. Breathing H₂-O₂ significantly improved the Borg score and resistance parameters of IOS but not vital signs. No adverse reactions occurred. H₂ was undetectable in the environment throughout the procedure. Conclusions: Breathing H₂-O₂ may reduce the inspiratory effort in patients with acute severe tracheal stenosis and can be used for this purpose safely.

Detecting tumor cells in peripheral blood and BALF may sensitive to identify benign and malignant peripheral lung lesions and be of value for early diagnosis of lung cancer.

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