Machine learning for accurate detection of small airway dysfunction-related respiratory changes: an observational study.

BACKGROUND: The use of machine learning(ML) methods would improve the diagnosis of small airway dysfunction(SAD) in subjects with chronic respiratory symptoms and preserved pulmonary function(PPF). This paper evaluated the performance of several ML algorithms associated with the impulse oscillometry(IOS) analysis to aid in the diagnostic of respiratory changes in SAD. We also find out the best configuration for this task. METHODS: IOS and spirometry were measured in 280 subjects, including a healthy control group (n = 78), a group with normal spirometry (n = 158) and a group with abnormal spirometry (n = 44). Various supervised machine learning (ML) algorithms and feature selection strategies were examined, such as Support Vector Machines (SVM), Random Forests (RF), Adaptive Boosting (ADABOOST), Navie Bayesian (BAYES), and K-Nearest Neighbors (KNN). RESULTS: The first experiment of this study demonstrated that the best oscillometric parameter (BOP) was R5, with an AUC value of 0.642, when comparing a healthy control group(CG) with patients in the group without lung volume-defined SAD(PPFN). The AUC value of BOP in the control group was 0.769 compared with patients with spirometry defined SAD(PPFA) in the PPF population. In the second experiment, the ML technique was used. In CGvsPPFN, RF and ADABOOST had the best diagnostic results (AUC = 0.914, 0.915), with significantly higher accuracy compared to BOP (p < 0.01). In CGvsPPFA, RF and ADABOOST had the best diagnostic results (AUC = 0.951, 0.971) and significantly higher diagnostic accuracy (p < 0.01). In the third, fourth and fifth experiments, different feature selection techniques allowed us to find the best IOS parameters (R5, (R5-R20)/R5 and Fres). The results demonstrate that the performance of ADABOOST remained essentially unaltered following the application of the feature selector, whereas the diagnostic accuracy of the remaining four classifiers (RF, SVM, BAYES, and KNN) is marginally enhanced. CONCLUSIONS: IOS combined with ML algorithms provide a new method for diagnosing SAD in subjects with chronic respiratory symptoms and PPF. The present study's findings provide evidence that this combination may help in the early diagnosis of respiratory changes in these patients.

The prognostic value of C-reactive protein to albumin ratio in patients with sepsis: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to determine whether the C-reactive protein-to-albumin ratio (CAR) can serve as a prognostic marker in patients with sepsis. METHODS: Chinese and English databases were searched to retrieve the included literature. The pooled sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) of the summary receiver operating characteristic (SROC) with their 95% confidence interval (CI) were calculated using the bivariate model. Moreover, the hazard ratio (HR) and 95% CI were calculated using the random effect model. RESULTS: Nine articles comprising 3224 patients with sepsis were included in the meta-analysis. The pooled SEN was 0.73 (95% CI 0.65-0.80), the pooled SPE was 0.78 (95% CI 0.69-0.84), the pooled PLR was 3.29 (95% CI 2.15-5.03), the pooled NLR was 0.35 (95% CI 0.24-0.49), and the pooled DOR was 9.50 (95% CI 4.38-20.59). The AUC under the SROC was 0.82 (95% CI 0.78-0.85) for the prognostic meta-analysis. The pooled HR was 1.10 (95% CI 1.02-1.18). CONCLUSIONS: This meta-analysis suggests that a high CAR level is associated with increased mortality and a poor prognosis.

A pilot study of differential gene expressions in patients with cough variant asthma and classic bronchial asthma.

BACKGROUND: Despite extensive exploration of asthma, the mechanism of asthma has not been fully elucidated. Cough variant asthma (CVA) is considered as precursor to classical asthma (CA). Comparative study between CA and CVA may be helpful in further understanding the pathogenesis of asthma. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from CVA, CA and healthy adults. Each group consisted of five cases. Total RNA was extracted from the PBMCs. Agilent 4 × 44 K human genome oligo microarray was used to detect whole genome expression. Allogeneic clustering, Gene Ontology and KEGG analysis were performed to investigate differentially expressed genes (DEGs). Then, ten candidate genes were screened and verified by real-time PCR. RESULTS: Gene expressions were significantly different among the three groups, with 202 DEGs between the CA and the CVA groups. The Gene Ontology analysis suggested that the DEGs were significantly enriched in 'histone H4-K20 demethylation' and 'antigen processing and presentation of endogenous antigens'. HDC, EGR1, DEFA4, LTF, G0S2, IL4, TFF3, CTSG, FCER1A and CAMP were selected as candidate genes. However, the results of real-time PCR showed that the expression levels of FCER1A, IL4 and HDC in the cough variant asthma group were significantly different from those in the other two groups (p < 0.05). CONCLUSIONS: The pathogenesis of CVA and CA may be related to genes such as FCER1A, HDC and IL4. Further studies incorporating a larger sample size should be conducted to find more candidate genes and mechanisms.

Impulse oscillometry for detection of small airway dysfunction in subjects with chronic respiratory symptoms and preserved pulmonary function.

BACKGROUND: Subjects with chronic respiratory symptoms and preserved pulmonary function (PPF) may have small airway dysfunction (SAD). As the most common means to detect SAD, spirometry needs good cooperation and its reliability is controversial. Impulse oscillometry (IOS) may complete the deficiency of spirometry and have higher sensitivity. We aimed to explore the diagnostic value of IOS to detect SAD in symptomatic subjects with PPF. METHODS: The evaluation of symptoms, spirometry and IOS results in 209 subjects with chronic respiratory symptoms and PPF were assessed. ROC curves of IOS to detect SAD were analyzed. RESULTS: 209 subjects with chronic respiratory symptoms and PPF were included. Subjects who reported sputum had higher R5-R20 and Fres than those who didn't. Subjects with dyspnea had higher R5, R5-R20 and AX than those without. CAT and mMRC scores correlated better with IOS parameters than with spirometry. R5, R5-R20, AX and Fres in subjects with SAD (n = 42) significantly increased compared to those without. Cutoff values for IOS parameters to detect SAD were 0.30 kPa/L s for R5, 0.015 kPa/L s for R5-R20, 0.30 kPa/L for AX and 11.23 Hz for Fres. Fres has the largest AUC (0.665, P = 0.001) among these parameters. Compared with spirometry, prevalence of SAD was higher when measured with IOS. R5 could detect the most SAD subjects with a prevalence of 60.77% and a sensitivity of 81% (AUC = 0.659, P = 0.002). CONCLUSION: IOS is more sensitive to detect SAD than spirometry in subjects with chronic respiratory symptoms and PPF, and it correlates better with symptoms. IOS could be an additional method for SAD detection in the early stage of diseases.

Acute severe radiation pneumonitis among non-small cell lung cancer (NSCLC) patients with moderate pulmonary dysfunction receiving definitive concurrent chemoradiotherapy: Impact of pre-treatment pulmonary function parameters.

PURPOSE: Severe acute radiation pneumonitis (SARP) is a life-threatening complication of thoracic radiotherapy. Pre-treatment pulmonary function (PF) may influence its incidence. We have previously reported on the incidence of SARP among patients with moderate pulmonary dysfunction who received definitive concurrent chemoradiotherapy (dCCRT) for non-small cell lung cancer (NSCLC). METHODS: The clinical outcomes, dose-volume histograms (DVH), and PF parameters of 122 patients (forced expiratory volume in 1 s [FEV1%]: 60-69%) receiving dCCRT between 2013 and 2019 were recorded. SARP was defined as grade ≥3 RP occurring during or within 3 months after CCRT. Logistic regression, receiver operating characteristics curves (ROC), and hazard ratio (HR) analyses were performed to evaluate the predictive value of each factor for SARP. RESULTS: Univariate and multivariate analysis indicated that the ratio of carbon monoxide diffusing capacity (DLCO%; odds ratio [OR]: 0.934, 95% confidence interval [CI] 0.896-0.974, p = 0.001) and mean lung dose (MLD; OR: 1.002, 95% CI 1.001-1.003, p = 0.002) were independent predictors of SARP. The ROC AUC of combined DLCO%/MLD was 0.775 (95% confidence interval [CI]: 0.688-0.861, p = 0.001), with a sensitivity and specificity of 0.871 and 0.637, respectively; this was superior to DLCO% (0.656) or MLD (0.667) alone. Compared to the MLD-low/DLCO%-high group, the MLD-high/DLCO%-low group had the highest risk for SARP, with an HR of 9.346 (95% CI: 2.133-40.941, p = 0.003). CONCLUSION: The DLCO% and MLD may predict the risk for SARP among patients with pre-treatment moderate pulmonary dysfunction who receive dCCRT for NSCLC. Prospective studies are needed to validate our findings.

Correction to: The effect of corticosteroids on the mortality of patients with influenza pneumonia: a systematic review and meta-analysis.

An amendment to this paper has been published and can be accessed via the original article.

The effect of corticosteroids on mortality of patients with influenza pneumonia: a systematic review and meta-analysis.

BACKGROUND: The effect of corticosteroids on clinical outcomes in patients with influenza pneumonia remains controversial. We aimed to further evaluate the influence of corticosteroids on mortality in adult patients with influenza pneumonia by comparing corticosteroid-treated and placebo-treated patients. METHODS: The PubMed, Embase, Medline, Cochrane Central Register of Controlled Trials (CENTRAL), and Information Sciences Institute (ISI) Web of Science databases were searched for all controlled studies that compared the effects of corticosteroids and placebo in adult patients with influenza pneumonia. The primary outcome was mortality, and the secondary outcomes were mechanical ventilation (MV) days, length of stay in the intensive care unit (ICU LOS), and the rate of secondary infection. RESULTS: Ten trials involving 6548 patients were pooled in our final analysis. Significant heterogeneity was found in all outcome measures except for ICU LOS (I2 = 38%, P = 0.21). Compared with placebo, corticosteroids were associated with higher mortality (risk ratio [RR] 1.75, 95% confidence interval [CI] 1.30 ~ 2.36, Z = 3.71, P = 0.0002), longer ICU LOS (mean difference [MD] 2.14, 95% CI 1.17 ~ 3.10, Z = 4.35, P < 0.0001), and a higher rate of secondary infection (RR 1.98, 95% CI 1.04 ~ 3.78, Z = 2.08, P = 0.04) but not MV days (MD 0.81, 95% CI - 1.23 ~ 2.84, Z = 0.78, P = 0.44) in patients with influenza pneumonia. CONCLUSIONS: In patients with influenza pneumonia, corticosteroid use is associated with higher mortality. TRIAL REGISTRATION: PROSPERO (ID: CRD42018112384 ).

Rapid versus gradual lung function decline in bronchiolitis obliterans syndrome after haematopoietic stem cell transplantation is associated with survival outcome.

BACKGROUND AND OBJECTIVE: Bronchiolitis obliterans syndrome (BOS) after haematopoietic stem cell transplantation (HSCT) presents with lung function decline. The pattern of lung function decline after BOS diagnosis could impact prognostication of BOS as a complication after HSCT. The aim of this study was to assess the impact of lung function decline on overall survival (OS) in BOS subjects. METHODS: Subjects with BOS were compared to those without BOS and matched for age, gender, primary diagnoses, conditioning regimes and chronic graft versus host disease. Lung function tests at baseline, at BOS diagnosis and every 3 months after HSCT were evaluated. RESULTS: Of the 1461 subjects undergoing allogeneic HSCT (allo-HSCT) between 1998 and 2015, 95 (6.5%) were diagnosed with BOS. A total of 159 matched HSCT recipients without BOS were identified. A 25% decline in FEV1 within the first 3 months after BOS diagnosis would separate BOS subjects into a subgroup with initial rapid decline and another subgroup with initial gradual decline in lung function. The rapid decline group showed lower subsequent lung function parameters and significantly worse OS compared to the gradual decline group (P = 0.013). CONCLUSION: Post-HSCT BOS subjects with initial rapid lung function decline within 3 months after BOS diagnosis will have significantly poorer lung function and worse OS compared to those with initial gradual decline in lung function after BOS diagnosis. HSCT BOS patients with rapid initial decline in lung function warrant closer monitoring for the development of other post-HSCT complications that could affect their survival.

Can corticosteroids reduce the mortality of patients with severe sepsis? A systematic review and meta-analysis.

BACKGROUND: The effects of corticosteroids on clinical outcomes of patients with sepsis remains controversial. We aimed to further determine the effectiveness of corticosteroids in reducing mortality in adult patients with severe sepsis by comparison with placebo. METHODS: Pubmed, Embase, Medline, Cochrane Central Register of Controlled Trials (CENTRAL) as well as the Information Sciences Institute (ISI) Web of Science were searched for all controlled studies that compared corticosteroids and placebo in adult patients with severe sepsis. The primary outcome was the mortality 28-day mortality and the secondary outcomes were mortality at longest follow up, occurrence, and reoccurrence of septic shock. RESULTS: A total of 19 trials involving 7035 patients were pooled in our final analyses. No significant heterogeneity was found in any of the outcome measures. Compared with placebo, corticosteroids were associated with a lower 28-day mortality (RR 0.91, 95% CI 0.85-0.98, Z = 2.57, P = 0.01) both in patients having sepsis and in those who developed septic shock (RR 0.92, 95% CI 0.85-0.99, Z = 2.19, P = 0.03), while no significant difference was found in mortality with the longest follow up in patients either having sepsis (RR 0.94, 95% CI 0.89-1.00, Z = 1.93, P = 0.05), or occurrence (RR 0.83, 95% CI 0.56-1.24, Z = 0.90, P = 0.37) or reoccurrence of septic shock (RR 1.08, 95% CI 1.00-1.16, Z = 1.89, P = 0.06). CONCLUSIONS: Corticosteroids were effective in reducing the 28-day mortality in patients with severe sepsis and in those with septic shock.

The effect of hyperoxia on mortality in critically ill patients: a systematic review and meta analysis.

BACKGROUND: Studies investigating the role of hyperoxia in critically ill patients have reported conflicting results. We did this analysis to reveal the effect of hyperoxia in the patients admitted to the intensive care unit (ICU). METHODS: Electronic databases were searched for all the studies exploring the role of hyperoxia in adult patients admitted to ICU. The primary outcome was mortality. Random-effect model was used for quantitative synthesis of the adjusted odds ratio (aOR). RESULTS: We identified 24 trials in our final analysis. Statistical heterogeneity was found between hyperoxia and normoxia groups in patients with mechanical ventilation (I2 = 92%, P < 0.01), cardiac arrest(I2 = 63%, P = 0.01), traumatic brain injury (I2 = 85%, P < 0.01) and post cardiac surgery (I2 = 80%, P = 0.03). Compared with normoxia, hyperoxia was associated with higher mortality in overall patients (OR 1.22, 95% CI 1.12~1.33), as well as in the subgroups of cardiac arrest (OR 1.30, 95% CI 1.08~1.57) and extracorporeal life support (ELS) (OR 1.44, 95% CI 1.03~2.02). CONCLUSIONS: Hyperoxia would lead to higher mortality in critically ill patients especially in the patients with cardiac arrest and ELS.

Can Systemic Thrombolysis Improve Prognosis of Cardiac Arrest Patients During Cardiopulmonary Resuscitation? A Systematic Review and Meta-Analysis.

BACKGROUND: Cardiac arrests are caused in most cases by thromboembolic diseases, such as acute myocardial infarction (AMI) and pulmonary embolism (PE). OBJECTIVE: We aimed to ascertain the associations of thrombolytic therapy with potential benefits among cardiac arrest patients during cardiopulmonary resuscitation (CPR). METHODS: We searched PubMed, Embase, and Cochrane databases for studies that evaluated systemic thrombolysis in cardiac arrest patients. The primary outcome was survival to hospital discharge, and secondary outcomes included return of spontaneous circulation (ROSC), 24-h survival rate, hospital admission rate, and bleeding complications. RESULTS: Nine studies with a total of 4384 cardiac arrest patients were pooled in the meta-analysis, including 1084 patients receiving systemic thrombolysis and 3300 patients receiving traditional treatments. Compared with conventional therapies, the use of systemic thrombolysis did not significantly improve survival to hospital discharge (13.5% vs. 10.8%; risk ratio [RR] 1.13; 95% confidence interval [CI] 0.92-1.39; p = 0.24, I2 = 35%), ROSC (50.9% vs. 44.3%; RR 1.29; 95% CI 1.00-1.66; p = 0.05, I2 = 73%), and 24-h survival (28.1% vs. 25.6%; RR 1.25; 95% CI 0.88-1.77; p = 0.22, I2 = 63%). We observed higher hospital admission rates for patients receiving systemic thrombolysis (43.4% vs. 30.6%; RR 1.53; 95% CI 1.04-2.24; p = 0.03, I2 = 87%). In addition, higher risk of bleeding was observed in the thrombolysis group (8.8% vs. 5.0%; RR 1.65; 95% CI 1.16-2.35; p = 0.005, I2 = 7%). CONCLUSIONS: Systemic thrombolysis during CPR did not improve hospital discharge rate, ROSC, and 24-h survival for cardiac arrest patients. Patients receiving thrombolytic therapy have a higher risk of bleeding. More high-quality studies are needed to confirm our results.

Efficacy and safety of antagonists for chemoattractant receptor-homologous molecule expressed on Th2 cells in adult patients with asthma: a meta-analysis and systematic review.

BACKGROUND: Chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) antagonists are novel agents for asthma but with controversial efficacies in clinical trials. Therefore, we conducted a meta-analysis to determine the roles of CRTH2 antagonists in asthma. METHODS: We searched in major databases for RCTs comparing CRTH2 antagonists with placebo in asthma. Fixed- or random-effects model was performed to calculate mean differences (MD), risk ratio (RR) or risk difference (RD) and 95% confidence interval (CI). RESULTS: A total of 14 trails with 4671 participants were included in our final analysis. Instead of add-on treatment of CRTH2 antagonists to corticosteroids, CRTH2 antagonist monotherapy significantly improved pre-bronchodilator FEV1 (MD = 0.09, 95% CI 0.04 to 0.15, P = 0.0005), FEV1% predicted (MD = 3.65, 95% CI 1.15 to 6.14, P = 0.004), and AQLQ (MD = 0.25, 95% CI 0.09 to 0.41, P = 0.002), and reduced asthma exacerbations (RR = 0.45, 95% CI 0.23 to 0.85, P = 0.01). Rescue use of SABA was significantly decreased in both CRTH2 antagonist monotherapy (MD = - 0.04, 95% CI -0.05 to - 0.03, P < 0.00001) and as add-on to corticosteroids (MD = - 0.78, 95% CI -1.47 to - 0.09, P = 0.03). Adverse events were similar between the intervention and placebo groups. CONCLUSIONS: CRTH2 antagonist monotherapy can safely improve lung function and quality of life, and reduce asthma exacerbations and SABA use in asthmatics.

Efficacy and safety of phosphodiesterase 4 inhibitors in patients with asthma: A systematic review and meta-analysis.

Phosphodiesterase 4 (PDE4) inhibitors are a novel medication approved for airway inflammatory diseases including chronic obstructive pulmonary disease. Their role and application in asthma are controversial and not defined. A comprehensive search was performed in major databases (1946-2016) using the keywords: 'phosphodiesterase 4 inhibitor' or 'roflumilast' and 'asthma'. Placebo-controlled trials reporting lung function, airway hyperresponsiveness by direct challenge, asthma control and exacerbations, and adverse events were included. Random or fixed-effects models were used to calculate odds ratios (OR) and mean differences between the two treatment groups. Statistical analyses were conducted using Mann-Whitney U-tests and Cochrane systematic review software, Review Manager. Seventeen studies were included in the systematic review, of which 14 studies were included in the meta-analysis. Except for significant statistical heterogeneity in pre- and post-challenge predicted percentage of forced expiratory volume in 1 s (FEV1 %; I2 = 72%, χ2 = 3.35, P = 0.06), there was no heterogeneity in outcome measures. Roflumilast (500 µg) significantly improved FEV1 (mean difference: 0.05, 95% CI: 0.01-0.09, Z = 2.50, P = 0.01), peak expiratory flow, asthma control and exacerbations, but showed variable effects on airway responsiveness to methacholine and a 20% fall in FEV1 .Of note, PDE4 inhibitors were accompanied with significantly higher adverse events such as headache (OR: 3.99, 95% CI: 1.65-9.66, Z = 3.07, P = 0.002) and nausea (OR: 5.53, 95% CI: 1.38-22.17, Z = 2.41, P = 0.02). In patients with mild asthma, oral PDE4 inhibitors can be considered as an alternative treatment to regular bronchodilators and inhaled controllers.

The effect of aspirin in preventing the acute respiratory distress syndrome/acute lung injury: A meta-analysis.

BACKGROUND: The effects of aspirin in preventing the occurrence of acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) among adult patients are controversial. We aimed to further determine the effectiveness of aspirin in reducing the rate of ARDS/ALI. METHODS: The Pubmed, Embase, Medline, ClinicalTrials.gov, Cochrane Central Register of Controlled Trials (CENTRAL) as well as the Information Sciences Institute (ISI) Web of Science were searched for all controlled studies that research the role of aspirin in adult patients who have the risk of ARDS/ALI. The outcomes were the ARDS/ALI rate and the mortality. Cochrane systematic review software, Review Manager (RevMan), the R software for statistical computing version 3.2.0, and the metafor package were used to test the hypothesis by Mann-Whitney U test. The heterogeneity test and sensitivity analyses were conducted, and random-effects or fixed-effects model was applied to calculate odds ratio (OR) and mean difference (MD) for dichotomous and continuous data, respectively. RESULTS: Six trials involving 6562 patients were pooled in our final study. No significant heterogeneity was found in outcome measures. Aspirin could reduce the rate of ARDS/ALI (OR 0.71, 95% confidence interval (CI) 0.58-0.86) but not the mortality (OR 0.87, 95% CI 0.71-1.07). CONCLUSIONS: In patients with risk of ARDS/ALI, aspirin could provide protective effect on the rate of ARDS/ALI, but it could not reduce the mortality.

The effect of high-flow nasal cannula in reducing the mortality and the rate of endotracheal intubation when used before mechanical ventilation compared with conventional oxygen therapy and noninvasive positive pressure ventilation. A systematic review and meta-analysis.

BACKGROUND: The effects of high flow nasal cannula (HFNC) on adult patients when used before mechanical ventilation (MV) are unclear. We aimed to determine the effectiveness of HFNC when used before MV by comparison to conventional oxygen therapy (COT) and noninvasive positive pressure ventilation (NIPPV). METHODS: The Pubmed, Embase, Medline, Cochrane Central Register of Controlled Trials (CENTRAL) as well as the Information Sciences Institute (ISI) Web of Science were searched for all the controlled studies that compared HFNC with NIPPV and COT when used before MV in adult patients. The primary outcome was the rate of endotracheal intubation and the secondary outcomes were intensive care unit (ICU) mortality and length of ICU stay (ICU LOS). RESULTS: Eight trials with a total of 1084 patients were pooled in our final studies. No significant heterogeneity was found in outcome measures. Compared both with COT and NIPPV, HFNC could reduce both of the rate of endotracheal intubation (OR 0.62, 95% CI 0.38-0.99, P=0.05; OR 0.48, 95% CI 0.31-0.73, P=0.0006) and ICU mortality (OR 0.47, 95% CI 0.24-0.93, P=0.03; OR 0.36, 95% CI 0.20-0.63, P=0.0004). As for the ICU LOS, we did not find any advantage of HFNC over COT or NIPPV. CONCLUSIONS: When used before MV, HFNC can improve the prognosis of patients compared both with the COT and NIPPV.

Can body mass index predict clinical outcomes for patients with acute lung injury/acute respiratory distress syndrome? A meta-analysis.

BACKGROUND: The effects of body mass index (BMI) on the prognosis of acute respiratory distress syndrome (ARDS) are controversial. We aimed to further determine the relationship between BMI and the acute outcomes of patients with ARDS. METHODS: We searched the Pubmed, Embase, Medline, Cochrane Central Register of Controlled Trials (CENTRAL), and ISI Web of Science for trials published between 1946 and July 2016, using "BMI" or "body mass index" or "overweight" or "obese" and "ARDS" or "ALI" or "acute respiratory distress syndrome" or "acute lung injury", without limitations on publication type or language. Heterogeneity and sensitivity analyses were conducted, and a random-effects model was applied to calculate the odds ratio (OR) or mean difference (MD). Review Manager (RevMan) was used to test the hypothesis using the Mann-Whitney U test. The primary outcome was unadjusted mortality, and secondary outcomes included mechanical ventilation (MV)-free days and length of stay (LOS) in the intensive care unit (ICU) and in hospital. RESULTS: Five trials with a total of 6268 patients were pooled in our final analysis. There was statistical heterogeneity between normal-weight and overweight patients in LOS in the ICU (I 2 = 71%, χ 2 = 10.27, P = 0.02) and in MV-free days (I 2 = 89%, χ 2 = 18.45, P < 0.0001). Compared with normal weight, being underweight was associated with higher mortality (OR 1.59, 95% confidence interval (CI) 1.22, 2.08, P = 0.0006), while obesity and morbid obesity were more likely to result in lower mortality (OR 0.68, 95% CI 0.57, 0.80, P < 0.00001; OR 0.72, 95% CI 0.56, 0.93, P = 0.01). MV-free days were much longer in patients with morbid obesity (MD 2.64, 95% CI 0.60, 4.67, P = 0.01), but ICU and hospital LOS were not influenced by BMI. An important limitation of our analysis is the lack of adjustment for age, sex, illness severity, comorbid illness, and interaction of outcome parameters. CONCLUSIONS: Obesity and morbid obesity are associated with lower mortality in patients with ARDS.

The effect of sedation and/or analgesia as rescue treatment during noninvasive positive pressure ventilation in the patients with Interface intolerance after Extubation.

BACKGROUND: Sedation and/or analgesia can relieve the patient-ventilator asynchrony. However, whether sedation and/or analgesia can benefit the clinical outcome of the patients with interface intolerance is still unclear. METHODS: A retrospective study was performed on patients with interface intolerance who received noninvasive positive pressure ventilation (NIPPV) after extubation in seven intensive care units (ICU) of West China Hospital, Sichuan University. The primary outcome was rate of NIPPV failure (defined as need for reintubation and mechanical ventilation); Secondary outcomes were hospital mortality rate and length of ICU stay after extubation. RESULTS: A total of 80 patients with oral-nasal mask (90%) and facial mask (10%) were included in the analysis. 41 out of 80 patients received sedation and/or analgesia treatment (17 used analgesia, 11 used sedation and 13 used both) at some time during NIPPV. They showed a decrease of NIPPV failure rate, (15% vs. 38%, P = 0.015; adjusted odd ratio [OR] 0.29, 95% confidence interval [CI] 0.10-0.86, P = 0.025), mortality rate (7% vs. 33%, P = 0.004; adjusted OR 0.14, 95% CI 0.03-0.60, P = 0.008), and the length of ICU stay after extubation. CONCLUSION: This clinical study suggests that sedation and/or analgesia treatment can decrease the rate of NIPPV failure, hospital mortality rate and ICU LOS in patients with interface intolerance after extubution during NIPPV.

Can high-flow nasal cannula reduce the rate of reintubation in adult patients after extubation? A meta-analysis.

BACKGROUND: The effects of high flow nasal cannula (HFNC) on adult patients after extubation remain controversial. We aimed to further determine the effectiveness of HFNC in comparison to noninvasive positive pressure ventilation (NIPPV) and conventional oxygen therapy (COT). METHODS: The Pubmed, Embase, Medline, Cochrane Central Register of Controlled Trails (CENTRAL) as well as the Information Sciences Institute (ISI) Web of Science were searched for all the controlled study comparing HFNC with NIPPV and COT in adult patients after extubation. The primary outcome was rate of reintubation and the secondary outcomes were intensive care unit (ICU) mortality and length of ICU stay (ICU LOS). RESULTS: Eight trials with a total of 2936 patients were pooled in our final studies. No significant heterogeneity was found in outcome measures. Compared with COT, HFNC was associated with lower rate of reintubation (Z = 2.97, P = 0.003), and the same result was found in the comparison between HFNC and NIPPV (Z = 0.87, P = 0.38). As for the ICU mortality and ICU LOS, we did not find any advantage of HFNC over COT or NIPPV. CONCLUSIONS: In patients after extubation, HFNC is a reliable alternative of NIPPV to reduce rate of reintubation compared with COT.

Can roflumilast, a phosphodiesterase-4 inhibitor, improve clinical outcomes in patients with moderate-to-severe chronic obstructive pulmonary disease? A meta-analysis.

BACKGROUND: Effects of roflumilast on lung function, symptoms, acute exacerbation and adverse events in patients with chronic obstructive pulmonary disease (COPD) are controversial. We aimed to further clarify the efficacy and safety of roflumilast in treatment of moderate-to-severe COPD. METHODS: From 1946 to November 2015, we searched the Pubmed, Embase, Medline, Cochrane Central Register of Controlled Trials, ISI Web of Science and American College of Physician using "roflumilast" and "chronic obstructive pulmonary disease" or "COPD". Randomized controlled trials that reported forced expiratory volume in one second (FEV1), forced vital capacity (FVC), transition dyspnea index (TDI), St George's Respiratory Questionnaire (SGRQ), and incidence of COPD exacerbations and adverse events were eligible. We conducted the heterogeneities test and sensitivity analysis, and random-effects or fixed-effects model was applied to calculate risk ratio (RR) and mean difference (MD) for dichotomous and continuous data respectively. Cochrane systematic review software, Review Manager (RevMan), was used to test the hypothesis by Mann-Whitney U-test. RESULTS: Thirteen trials with a total of 14,563 patients were pooled in our final studies. Except for SGRQ (I (2) = 63 %, χ (2) = 1.71, P = 0.07) and adverse events (I (2) = 94 %, χ (2) = 0.03, P < 0.001), we did not find statistical heterogeneity in outcome measures. The pooled MD of pre- and post-bronchodilator FEV1 was 54.60 (95 % confidence interval (CI) 46.02 ~ 63.18) and 57.86 (95 % CI 49.80 ~ 65.91), and both showed significant improvement in patients with roflumilast (z = 12.47, P <0.001; z = 14.07, P < 0.001), so did in FVC (MD 90.37, 95 % CI 73.95 ~ 106.78, z = 10.79, P < 0.001). Significant alleviation of TDI (MD 0.30, 95 % CI 0.14 ~ 0.46, z = 3.67, P < 0.001) and decrease of acute exacerbation (RR 0.86, 95 % CI 0.81 ~ 0.91, z = 5.54, P < 0.001) were also identified in treatment of roflumilast, but without significant difference in SGRQ (MD -1.30, 95 % CI -3.16 ~ 0.56, z = 1.37, P = 0.17). Moreover, roflumilast significantly increased the incidence of adverse events compared with placebo (RR 1.31, 95 % CI 1.16 ~ 1.47, z = 4.32, P < 0.001). CONCLUSIONS: Roflumilast can be considered as an alternative therapy in selective patients with moderate-to-severe COPD.