Effects of pulmonary surfactant combined with noninvasive positive pressure ventilation in neonates with respiratory distress syndrome

BACKGROUND Neonatal respiratory distress syndrome(NRDS)is one of the most common diseases in neonatal intensive care units,with an incidence rate of about 7%among infants.Additionally,it is a leading cause of neonatal death in hospitals in China.The main mechanism of the disease is hypoxemia and hypercapnia caused by lack of surfactant AIM To explore the effect of pulmonary surfactant(PS)combined with noninvasive positive pressure ventilation on keratin-14(KRT-14)and endothelin-1(ET-1)levels in peripheral blood and the effectiveness in treating NRDS.METHODS Altogether 137 neonates with respiratory distress syndrome treated in our hospital from April 2019 to July 2021 were included.Of these,64 control cases were treated with noninvasive positive pressure ventilation and 73 observation cases were treated with PS combined with noninvasive positive pressure ventilation.The expression of KRT-14 and ET-1 in the two groups was compared.The deaths,complications,and PaO_(2),PaCO_(2),and PaO_(2)/FiO_(2)blood gas indexes in the two groups were compared.Receiver operating characteristic curve(ROC)analysis was used to determine the diagnostic value of KRT-14 and ET-1 in the treatment of NRDS.RESULTS The observation group had a significantly higher effectiveness rate than the control group.There was no significant difference between the two groups in terms of neonatal mortality and adverse reactions,such as bronchial dysplasia,cyanosis,and shortness of breath.After treatment,the levels of PaO_(2)and PaO_(2)/FiO_(2)in both groups were significantly higher than before treatment,while the level of PaCO_(2)was significantly lower.After treatment,the observation group had significantly higher levels of PaO_(2)and PaO_(2)/FiO_(2)than the control group,while PaCO_(2)was notably lower in the observation group.After treatment,the KRT-14 and ET-1 levels in both groups were significantly decreased compared with the pre-treatment levels.The observation group had a reduction of KRT-14 and ET-1 levels than the control group.ROC curve analysis showed that the area under the curve(AUC)of KRT-14 was 0.791,and the AUC of ET-1 was 0.816.CONCLUSION Combining PS with noninvasive positive pressure ventilation significantly improved the effectiveness of NRDS therapy.KRT-14 and ET-1 levels may have potential as therapeutic and diagnostic indicators.

Analysis of the Effect of Non-Invasive Positive Pressure Ventilation in Emergency Treatment of Severe Bronchial Asthma with Respiratory Failure

Objective:This study aims to evaluate the clinical efficacy of non-invasive positive pressure ventilation(NIPPV)in patients with severe bronchial asthma combined with respiratory failure.Methods:90 patients with severe bronchial asthma combined with respiratory failure between September 2022 and December 2023 were selected for the study and randomly divided into the experimental group(NIPPV-assisted treatment)and the control group.The differences between the two groups were compared in terms of total effective rate of treatment,days of clinical symptom disappearance,days of hospitalization,lung function indexes,incidence of adverse reactions,and quality of life.Results:Patients in the experimental group had a significantly higher total effective rate of treatment(97.78%)than the control group(75.56%).In terms of pulmonary function indexes,patients in the experimental group showed significant improvement after treatment,especially the increase in forced expiratory volume and forced vital capacity,while these improvements were not as obvious in the control group.In addition,the incidence of adverse reactions was significantly lower in the experimental group than in the control group,suggesting that the application of NIPPV is relatively safe.Quality of life assessment also showed that patients in the experimental group had significantly better quality of life than the control group after treatment.Conclusion:This study demonstrated the effectiveness of NIPPV as an adjunctive treatment for severe bronchial asthma combined with respiratory failure.NIPPV can improve lung function,reduce the incidence of adverse effects,increase the overall effectiveness of the treatment,and contribute to the improvement of patients'quality of life.Therefore,NIPPV should be regarded as an effective and safe treatment in clinical management,especially in patients with severe bronchial asthma combined with respiratory failure,where its application has potential clinical significance.

Non-Invasive Positive Pressure Ventilation (NIPPV) in the Pregnant Patient: A Case Series

Rationale: Acute respiratory failure is an uncommon complication of pregnancy. However, it is the most frequent organ dysfunction associated with obstetric admissions to an intensive care unit. The obstetric population is a different group due to its physiology and the presence of the fetus that lacks evidence in the literature within the subject of ventilatory support. Noninvasive positive pressure ventilation (NIPPV) is often avoided due to the lack of knowledge on the safety and efficacy of this modality. Currently, there are no guidelines for the management of respiratory failure in pregnancy. Objectives: To provide evidence in support of the use of NIPPV as a safe and reasonable modality for pregnant patients with respiratory failure. Methods: We retrospectively reviewed medical records of 29 pregnant patients of the Obstetric Critical Care Unit of a tertiary hospital in Panamá City who received NIPPV from 2013 to 2015. Failure to response was defined as the lack of increase in the paO2/FiO2 ratio or clinical deterioration 6 hours after initiating NIPPV. Demographics, indication for NIPPV, duration of treatment, as well as maternal and fetal outcomes were collected. Measurements and Main Results: Mean age was 28.4 ± 6 years, mean body mass index 27.4 ± 3.3, and mean gestational age at admission was 305/7 ± 5 weeks. Twenty-four patients (82.8%) met the criteria for acute lung injury (ALI) and an additional two (6.9%) for acute respiratory distress syndrome (ARDS). The mean duration of ventilation was 50.6 ± 17.27 hours. Statistically significant differences were noted between the paO2/FiO2 ratios in failure and successful patients within 2 hours of NIPPV therapy (P = 0.007) and paO2/FiO2 ratio within 6 hours of NIPPV therapy (P = 0.03). Success was defined when the patient was administered NIPPV, resulting in an improvement (increase in pa/FiO2 ratio) of her ventilatory parameters. Three patients (10.3%) failed to respond to NIPPV and needed to be converted to invasive mechanical ventilation. Patients who required intubation had a longer duration of ICU stay (P = 0.006) and overall hospital stay (P = 0.03). None of patients presented aspiration during NIPPV therapy. Conclusion: The current series is the largest report of pregnant patients requiring ventilatory support who received NIPPV as first line of therapy. This report shows the usefulness of this ventilation modality, avoiding intubation with its risks, of a significant number of patients, especially ventilator-associated pneumonia.

Impact of noninvasive positive pressure ventilation on the gene expression of ubiquitin system of skeletal muscle in patients with acute exacerbation of chronic obstructive pulmonary disease

Objective:To investigate the change and relativity of noninvasive positive pressure ventilation(NIPPV)on the gene expression of ubiquitin system of skeletal muscle in patient with acute exacerbation of chronic obstructive pulmonary disease(AECOPD).Methods:80 patients with AECOPD were divided into two groups based on whether the NIPPV treatment was given or not,38 cases in the study group and 42 in the control group.The blood gas analysis and pulmonary function were monitored and recorded before and 14 days after treatment.A skeletal muscle biopsy was performed 14 days after therapy.The mRNA expression of ribosomal protein S21(RPS21)and ubiquitin in skeletal muscle cell were measured by RT-PCR.Results:After 14 days treatment,the levels of PaCO_(2),PaO_(2),PH and FEV_(1)% in the NIPPV group improved much better than in the control group(p<.05).The gene expression of RPS21 and ubiquitin was obviously lower in the study group than in the control group(p<.05).The level of RPS21 was negatively related with PaO_(2),PH and FEV1%,and the level of ubiquitin was negatively related with PaO_(2) and FEV1%,but positively correlated with PaCO_(2).The area under the ROC curves of RPS21,ubiquitin,PaCO_(2) and FEV_(1)% were 0.771,0.885,0.821 and 0.734 respectively in the study group.The cut-off points were 103.978,8.128,45.350 and 51.350 respectively.The sensitivity evaluation of acid poisoning was 90.9%,and the specificities for each were 75%,75%,50% and 50%.Conclusions:NIPPV is effective for AECOPD patients through the gene expression of ubiquitin system of skeletal muscle.

Clinical Study on Respiratory Medicine Treatment of Chronic Obstructive Pulmonary Disease Combined with Respiratory Failure

Objective:To explore the respiratory medicine treatment methods for treating chronic obstructive pulmonary disease(COPD)combined with respiratory failure.Methods:70 cases of COPD patients with combined respiratory failure admitted to our hospital from January 2021 to January 2023 were selected as the study subjects,and randomly divided into the control group and the experimental group,each with 35 cases.The control group received only conventional treatment,and the experimental group received non-invasive positive pressure ventilation,and the treatment effects and changes in the levels of IL-18,hs-CRP,and CES2 inflammatory factors were observed and evaluated in the two groups.Results:There was no significant difference between the general data of the two groups(P>0.05);after treatment,the total effective rate of clinical efficacy of the observation group(91.43%)was significantly higher than that of the control group(71.43%),and the difference showed a significant correlation(P<0.05);after treatment,the level of inflammatory factor of the observation group was significantly reduced compared with that of the control group,and the difference showed a highly significant correlation(P<0.001).Conclusion:The non-invasive positive pressure ventilation treatment program significantly improves the therapeutic effect,effectively controls the level of inflammatory factors,and improves the health status of patients when dealing with patients with chronic obstructive pulmonary disease accompanied by respiratory failure,showing a good clinical application prospect.

Correlation of Inferior Vena Cava Respiratory Variability Index with Central Venous Pressure and Hemodynamic Parameters in Ventilated Pigs with Septic Shock

Septic shock is a common critical condition, for which effective early fluid resuscitation is the therapeutic focus. According to the 2008 international guidelines for management of severe sepsis and septic shock, resuscitation should achieve a central venous pressure （CVP） of 8-12 mmHg within the first 6 h. However, it is still uncertain about the sensitivity and specificity of CVP in reflecting the cardiac preload. Ultrasonography is a simple, rapid, non-invasive, and repeatable method for the measurement of sensitivity and specificity of CVP and has thus gradually attracted the increasing attention of physicians. It was reported that ultrasonography can show the inferior vena cava diameter, respiratory variability index, and blood volume in patients with sepsis or heart failure.

Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

Based on the simulated laboratory experiment of pressure balance for fire ex- tinguishing,the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine.The technology includes three measures for air pressure regulation, namely applying the pressure regulating chamber to balance the air pressure of fire district, increasing the air pressure of the working face,and filling the ground surface fractures.A good effect was obtained to prevent and extinguish the fire.When the measures fail to in- crease the pressure of working face or to regulate that of air chamber,the measure to fill the ground surface fractures will play an important role.

Clinical study of NFNC in the treatment of acute exacerbation chronic obstructive pulmonary disease patients with respiratory failure

BACKGROUND Most patients with acute exacerbation chronic obstructive pulmonary disease(AECOPD)have respiratory failure that necessitates active correction and the improvement of oxygenation is particularly important during treatment.High flow nasal cannula(HFNC)oxygen therapy is a non-invasive respiratory aid that is widely used in the clinic that improves oxygenation state,reduces dead space ventilation and breathing effort,protects the loss of cilia in the airways,and improves patient comfort.AIM To compare HFNC and non-invasive positive pressure ventilation in the treatment of patients with AECOPD.METHODS Eighty AECOPD patients were included in the study.The patients were in the intensive care department of our hospital from October 2019 to October 2021.The patients were divided into the control and treatment groups according to the different treatment methods with 40 patients in each group.Differences in patient comfort,blood gas analysis and infection indices were analyzed between the two groups.RESULTS After treatment,symptoms including nasal,throat and chest discomfort were significantly lower in the treatment group compared to the control group on the 3rd and 5th days(P<0.05).Before treatment,the PaO_(2),PaO_(2)/FiO_(2),PaCO_(2),and SaO_(2)in the two groups of patients were not significantly different(P>0.05).After treatment,the same indicators were significantly improved in both patient groups but had improved more in the treatment group compared to the control group(P<0.05).After treatment,the white blood cell count,and the levels of C-reactive protein and calcitonin in patients in the treatment group were significantly higher compared to patients in the control group(P<0.05).CONCLUSION HFNC treatment can improve the ventilation of AECOPD patients whilst also improving patient comfort,and reducing complications.HFNC is a clinically valuable technique for the treatment of AECOPD.

Effectiveness and safety of noninvasive positive-pressure ventilation for severe hypercapnic encephalopathy due to acute exacerbation of chronic obstructive pulmonary disease:a prospective case-control study

Background Although severe encephalopathy has been proposed as a possible contraindication to the use of noninvasive positive-pressure ventilation （NPPV）, increasing clinical reports showed it was effective in patients with impaired consciousness and even coma secondary to acute respiratory failure, especially hypercapnic acute respiratory failure （HARF）. To further evaluate the effectiveness and safety of NPPV for severe hypercapnic encephalopathy, a prospective case-control study was conducted at a university respiratory intensive care unit （RICU） in patients with acute exacerbation of chronic obstructive pulmonary disease （AECOPD） during the past 3 years. Methods Forty-three of 68 consecutive AECOPD patients requiring ventilatory support for HARF were divided into 2 groups, which were carefully matched for age, sex, COPD course, tobacco use and previous hospitalization history, according to the severity of encephalopathy, 22 patients with Glasgow coma scale （GCS） 〈10 served as group A and 21 with GCS 〉10 as group B. Results Compared with group B, group A had a higher level of baseline arterial partial CO2 pressure （（102±27） mmHg vs （74±17） mmHg, P〈0.01）, lower levels of GCS （7.5±1.9 vs 12.2±1.8, P〈0.01）, arterial pH value （7.18±0.06 vs 7.28±0.07, P〈0.01） and partial 02 pressure/fraction of inspired 02 ratio （168±39 vs 189±33, P〈0.05）. The NPPV success rate and hospital mortality were 73% （16/22） and 14% （3/22） respectively in group A, which were comparable to those in group B （68% （15/21） and 14% （3/21） respectively, all P〉0.05）, but group A needed an average of 7 cmH20 higher of maximal pressure support during NPPV, and 4, 4 and 7 days longer of NPPV time, RICU stay and hospital stay respectively than group B （P〈0.05 or P〈0.01）. NPPV therapy failed in 12 patients （6 in each group） because of excessive airway secretions （7 patients）, hemodynamic instability （2）, worsening of dyspnea and deterioration of gas exchange （2）, and gastric content aspiration （1）. Conclusions Selected patients with severe hypercapnic encephalopathy secondary to HARF can be treated as effectively and safely with NPPV as awake patients with HARF due to AECOPD; a trial of NPPV should be instituted to reduce the need of endotracheal intubation in patients with severe hypercapnic encephalopathy who are otherwise good candidates for NPPV due to AECOPD.

Effect of noninvasive, positive pressure ventilation on patients with severe, stable chronic obstructive pulmonary disease： a meta-analysis

Background This meta-analysis evaluated the effect of noninvasive, positive pressure ventilation on severe, stable chronic obstructive pulmonary disease （COPD）. Methods PUBMED, CNKI, Wanfang, EMBASE and the Cochrane trials databases were searched. Randomized controlled trials of patients with severe, stable COPD and receiving noninvasive positive pressure ventilation, compared with sham ventilation or no ventilation, were reviewed. The mortality, physiological and health related parameters were pooled to yield odds ratio （OR）, weighted mean differences or standardized mean differences （SMD）, with 95% confidence interval （CI）. Results Eight parallel and three crossover randomized controlled trials met the inclusion criteria. Pooled analysis for parallel, randomized controlled trials showed noninvasive positive pressure ventilation： （1） Did not affect the 12- or 24-month mortality （OR 0.82, 95% Ch 0.48 to 1.41）; （2） Improved the arterial carbon dioxide tension （SMD -0.88, 95% Ch -1.43 to -0.34）; （3） Did not improve forced expiratory volume in one second （SMD 0.20, 95% CI： -0.06 to 0.46）, maximal inspiratory pressure （SMD 0.01, 95% Ch -0.28 to 0.29） or 6-minute walk distance （SMD 0.17, 95% Ch -0.16 to 0.50）; （4） Subgroup analysis showed noninvasive positive pressure ventilation improved the arterial carbon dioxide tension in hypercapnic patients. Pooled analysis for crossover randomized controlled trials did not show improvement in arterial blood gas or forced expiratory volume in one second with noninvasive positive pressure ventilation. Conclusions Noninvasive positive pressure ventilation improves the arterial carbon dioxide tension but does not improve the mortality, pulmonary function, or exercise tolerance and should be cautiously used in severe stable chronic obstructive pulmonary disease.

Effect of noninvasive positive pressure ventilation on weaning success in patients receiving invasive mechanical ventilation： a meta-analysis

Background Noninvasive positive pressure ventilation （NIPPV） has been proposed to shorten the duration of mechanical ventilation in intubated patients, especially those who fail initial weaning from invasive mechanical ventilation （IMV）. However, there are also some discrepancies in terms of weaning success or failure, incidence of re-intubation, complications observed during study and patient outcomes. The primary objective of this update was to specifically investigate the role of NIPPV on facilitating weaning and avoiding re-intubation in patients intubated for different etiologies of acute respiratory failure, by comparing with conventional invasive weaning approach. Methods We searched randomized controlled trials （RCTs） comparing noninvasive weaning of early extubation and immediate application of NIPPV with invasive weaning in intubated patients from PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Knowledge and Springerlink databases. Records from conference proceedings and reference lists of relevant studies were also identified. Results A total of 11 RCTs with 623 patients were available for the present analysis. Compared with IMV, NIPPV significantly increased weaning success rates （odds ratio （OR）： 2.50, 95% confidence interval （C/）： 1.46-4.30, P=0.0009）, decreased mortality （OR： 0.39, 95% CI： 0.20-0.75, P=0.005）, and reduced the incidence of ventilator associated pneumonia （VAP） （OR： 0.17, 95% CI： 0.08-0.37, P 〈0.00001） and complications （OR： 0.22, 95% CI： 0.07-0.72, P=0.01）. However, effect of NIPPV on re-intubation did not reach statistical difference （OR： 0.61, 95% CI： 0.33-1.11, P=0.11）. Conclusions Early extubation and immediate application of NIPPV is superior to conventional invasive weaning approach in increasing weaning success rates, decreasing the risk of mortality and reducing the incidence of VAP and complications, in patients who need weaning from IMV. However, it should be applied with caution, as there is insufficient beneficial evidence to definitely recommend it in terms of avoidinQ re-intubation.

Efficacy and safety of noninvasive positive pressure ventilation in the treatment of acute respiratory failure after cardiac surgery

Background Although noninvasive positive pressure ventilation （NPPV） has been successfully used for various kinds of acute respiratory failure,the data are limited regarding its application in postoperative respiratory failure after cardiac surgery.Therefore,we conducted a prospective randomized control study in a university surgical intensive care unit to evaluate the efficacy and safety of NPPV in the treatment of acute respiratory failure after cardiac surgery,and explore the predicting factors of NPPV failure.Methods From September 2011 to November 2012 patients with acute respiratory failure after cardiac surgery who had indication for the use of NPPV were randomly divided into a NPPV treatment group （NPPV group） and the conventional treatment group （control group）.The between-group differences in the patients＇ baseline characteristics,re-intubation rate,tracheotomy rate,ventilator associated pneumonia （VAP） incidence,in-hospital mortality,mechanical ventilation time after enrollment （MV time）,intensive care unit （ICU） and postoperative hospital stays were compared.The factors that predict NPPV failure were analyzed.Results During the study period,a total of 139 patients who had acute respiratory failure after cardiac surgery were recorded,and 95 of them met the inclusion criteria,which included 59 males and 36 females with a mean age of （61.5±11.2） years.Forty-three patients underwent coronary artery bypass grafting （CABG）,23 underwent valve surgery,13 underwent CABG＋valve surgery,13 underwent major vascular surgery,and three underwent other surgeries.The NPPV group had 48 patients and the control group had 47 patients.In the NPPV group,the re-intubation rate was 18.8％,tracheotomy rate was 12.5％,VAP incidence was 0,and the in-hospital mortality was 18.8％,significantly lower than in the control group 80.9％,29.8％,17.0％ and 38.3％ respectively,P ＜0.05 or P ＜0.01.The MV time and ICU stay （expressed as the median （P25,P75）） were 18.0 （9.2,35.0） hours and 4.0 （2.0,5.0） days,which were significantly shorter than in the control group,96.0 （26.0,240.0） hours and 6.0 （4.0,9.0） days respectively,P ＜0.05 or P ＜0.01.The postoperative hospital stays of the two groups were similar.The univariate analysis showed that the NPPV success subgroup had more patients with acute lung injury （ALl） （17 vs.0,P=0.038）,fewer patients with pneumonia （2 vs.7,P ＜0.001） and lower acute physiology and chronic health evaluation Ⅱ （APACHE Ⅱ） scores （16.1±2.8 vs.21.8±3.2,P ＜0.001）.Multivariate analysis showed that pneumonia （P=-0.027） and a high APACHE Ⅱ score ＞20 （P=-0.002） were the independent risk factors of NPPV failure.Conclusions We conclude that NPPV can be applied in selected patients with acute respiratory failure after cardiac surgery to reduce the need of re-intubation and improve clinical outcome as compared with conventional treatment.Pneumonia and a high APACHE Ⅱ score ＞20 might be the independent risk factors of NPPV failure in this group of patients.

Early use of non-invasive positive pressure ventilation for acute exacerbations of chronic obstructive pulmonary disease:a multicentre randomized controlled trial

Background Respiratory muscle fatigue plays an important role in acute exacerbations of chronic obstructivepulmonary disease (AECOPD)·In previous clinical studies, non-invasive positive pressure ventilation (NPPV)was proved to be successful only for AECOPD patients with severe respiratory failure·We hypothesized that, theoutcomes of AECOPD would be improved if NPPVis early (within 24 to 48 hours of admission) administered inthose patients with respiratory muscle fatigue and mild respiratory insufficiency, especially in patients withoutfulfilling the conventional criteria of mechanical ventilatory support·Methods Aprospective multicentre randomized controlled trial was conducted in19 hospitals in China over16months·Three hundred and forty-two AECOPD patients with pH≥7·25 and PaCO2>45 mmHg were recruitedon general ward and randomly assigned to standard medical treatment (control group) or early administration ofadditional NPPV (NPPV group)·Results The characteristics of two groups on admission were similar·The number of AECOPD patientsrequiring intubations in NPPV group was much fewer than that of the control group (8/171 vs 26/71,P=0·002)·Subgroup analysis showed the needs for intubation in mildly (pH≥7·35) and severe (pH<7·30)acidotic patients in NPPVgroup were both decreased (9/80 vs2/71,P=0·047 and 8/30 vs3/43,P=0·048,respectively)·The mortality in hospital was reduced slightly by NPPV but with no significant difference (7/171vs 12/171,P=0·345)·Respiratory rate (RR),scale for accessory muscle use and arterial pHimproved rapidlyat the first 2 hours only in patients of NPPV group·After 24 hours, the differences of pH, PaO2, scale foraccessory muscle use and RR in NPPV group [(7·36±0·06) mmHg, (72±22) mmHg, (2·5±0·9) /min,(22±4) /min] were statistically significant compared with control group (7·37±0·05) mmHg, (85±34)mmHg, (2·3±1·1) /min, (21±4) /min,P<0·01 for all comparisons]·Conclusions The early use of NPPV on general ward improves arterial blood gas and respiratory pattern,decreases the rate of need for intubation in AECOPD patients·NPPV is indicative for alleviating respiratorymuscle fatigue and preventing respiratory failure from exacerbation·

Long-term non-invasive positive pressure ventilation in severe stable chronic obstructive pulmonary disease： a meta-analysis

Background The evidence for non-invasive positive pressure ventilation （NIPPV） used in patients with severe stable chronic obstructive pulmonary disease （COPD） is insufficient. The aim of the meta-analysis was to assess the treatment effects of long-term NIPPV on gas change, lung function, health-related quality of life （HRQL）, survival and mortality in severe stable COPD patients. Methods Randomized controlled trials （RCTs） and crossover studies comparing the treatment effects of NIPPV with conventional therapy were identified from electronic databases and reference lists from January 1995 to August 2010. Two reviewers independently assessed study quality. Data were combined using Review Manager 5.0. Both pooled effects and 95% confidence intervals were calculated. Results Five RCTs and one randomized crossover study with a total of 383 severe stable COPD patients were included NIPPV improved gas change significantly when using a higher inspiratory positive airway pressures. The weighted mean difference （WMD） for the partial pressure of carbon dioxide in artery （PaCO2） was -3.52 （-5.26, -1.77） mmHg and for the partial pressure of oxygen in artery （PaO2） 2.84 （0.23, 5.44） mmHg. There were significant improvements in dyspnea and sleep quality, but gained no benefits on lung function. The standardized mean difference （SMD） for the forced expiratory volume in 1 second （FEV1） was 0.00 （0.29, 0.29）. And the benefits for exercise tolerance, mood, survival and mortality remained unclear. Conclusions Patients with severe stable COPD can gain some substantial treatment benefits when using NIPPV, especially improvements in gas change, dyspnea and sleep quality. Studies of high methodological quality with large population, especially those based on a higher inspiratory positive airway pressures are required to provide more evidences.

Neural control of pressure support ventilation improved patient-ventilator synchrony in patients with different respiratory system mechanical properties:a prospective,crossover trial

Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing to an increased inspiratory effort.Using diaphragm electrical activity,neurally controlled pressure support(PSN)could hypothetically eliminate the asynchrony and reduce inspiratory effort.The purpose of this study was to compare the differences between PSN and PSP in terms of patient-ventilator synchrony,inspiratory effort,and breathing pattern.Methods:Eight post-operative patients without respiratory system comorbidity,eight patients with acute respiratory distress syndrome(ARDS)and obvious restrictive acute respiratory failure(ARF),and eight patients with chronic obstructive pulmonary disease(COPD)and mixed restrictive and obstructive ARF were enrolled.Patient-ventilator interactions were analyzed with macro asynchronies(ineffective,double,and auto triggering),micro asynchronies(inspiratory trigger delay,premature,and late cycling),and the total asynchrony index(AI).Inspiratory efforts for triggering and total inspiration were analyzed.Results:Total AI of PSN was consistently lower than that of PSP in COPD(3%vs.93%,P=0.012 for 100%support level;8%vs.104%,P=0.012 for 150%support level),ARDS(8%vs.29%,P=0.012 for 100%support level;16%vs.41%,P=0.017 for 150%support level),and post-operative patients(21%vs.35%,P=0.012 for 100%support level;15%vs.50%,P=0.017 for 150%support level).Improved support levels from 100%to 150%statistically increased total AI during PSP but not during PSN in patients with COPD or ARDS.Patients’inspiratory efforts for triggering and total inspiration were significantly lower during PSN than during PSP in patients with COPD or ARDS under both support levels(P<0.05).There was no difference in breathing patterns between PSN and PSP.Conclusions:PSN improves patient-ventilator synchrony and generates a respiratory pattern similar to PSP independently of any level of support in patients with different respiratory system mechanical properties.PSN,which reduces the trigger and total patient’s inspiratory effort in patients with COPD or ARDS,might be an alternative mode for PSP.Trial Registration:ClinicalTrials.gov,NCT01979627;https://clinicaltrials.gov/ct2/show/record/NCT01979627.

Efficacy of high-flow nasal cannula on acute exacerbation of chronic obstructive pulmonary disease: A meta-analysis

Objective:To systematically evaluate the efficacy and feasibility of high-flow nasal cannula(HFNC)on patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD).Methods:Systematic searches on PubMed,Web of Science,the Cochrane Library,Embase,CBM(Chinese Biomedicine Database),CNKI(China National Knowledge Infrastructure),Wanfang Database and VIP were performed for randomized controlled trials(RCTs)which explored the effects of HFNC on patients with AECOPD.The retrieval time was from the establishment of each database to July 2019.RevMan5.3 software was used for statistical analysis.Results:A total of 12 articles were included,involving 812 patients.The results showed that:(1)Compared with conventional oxygen therapy,HFNC could improve patients'arterial partial oxygen pressure(PaO2)(MD=12.70,95%CI(7.00,18.40),Z=4.37,P<0.0001),reduce partial arterial blood carbon dioxide(PaCO2)(MD=-10.99,95%CI(-14.42,-7.55),Z=6.26,P<0.00001)and reduce endotracheal intubation rate(OR=0.19,95%CI(0.04,0.93),Z=2.05,P=0.04),shorten the hospitalization time(SMD=-0.74,95%CI(-1.11,-0.37),Z=3.95,P<0.0001).(2)Compared with non-invasive positive pressure ventilation,it has fewer adverse reactions(OR=0.18,95%CI(0.09,0.35),Z=5.08,P<0.00001)and shorter hospital stay(SMD=-0.57,95%CI(-0.90,-0.23),Z=3.33,P=0.0009).Conclusion:HFNC can improve the patients’hypoxia symptoms and CO2 retention,reduce the rate of tracheal intubation,and alleviate adverse reactions.However,Limited by the quality and region of the included studies,more high-quality are needed to test it.

Does airway pressure release ventilation offer new hope for treating acute respiratory distress syndrome?

Mechanical ventilation(MV)is an essential life support method for patients with acute respiratory distress syn-drome(ARDS),which is one of the most common critical illnesses with high mortality in the intensive care unit(ICU).A lung-protective ventilation strategy based on low tidal volume(LTV)has been recommended since a few years;however,as this did not result in a significant decrease of ARDS-related mortality,a more optimal venti-lation mode was required.Airway pressure release ventilation(APRV)is an old method defined as a continuous positive airway pressure(CPAP)with a brief intermittent release phase based on the open lung concept;it also perfectly fits the ARDS treatment principle.Despite this,APRV has not been widely used in the past,rather only as a rescue measure for ARDS patients who are difficult to oxygenate.Over recent years,with an increased under-standing of the pathophysiology of ARDS,APRV has been reproposed to improve patient prognosis.Nevertheless,this mode is still not routinely used in ARDS patients given its vague definition and complexity.Consequently,in this paper,we summarize the studies that used APRV in ARDS,including adults,children,and animals,to illustrate the settings of parameters,effectiveness in the population,safety(especially in children),incidence,and mechanism of ventilator-induced lung injury(VILI)and effects on extrapulmonary organs.Finally,we found that APRV is likely associated with improvement in ARDS outcomes,and does not increase injury to the lungs and other organs,thereby indicating that personalized APRV settings may be the new hope for ARDS treatment.

Effect of chimney shadow on the performance of wind supercharged solar chimney power plants:A numerical case study for the Spanish prototype

Three-dimensional numerical simulations for a solar chimney power plant(SCPP)and wind supercharged solar chimney power plant(WSSCPP)based on the Spanish prototype using the solar ray-tracing algorithm were performed to study the shadow effect of the chimney.The area of the shadow region increases with an increase in the incident angle of the solar rays.A parametric study was performed by varying the incident angle from 0°to 30°.The temperature and velocity distributions at different incident angles were analyzed.In addition,we investigated the chimney shadow effect in several comprehensive SCPP systems.The findings show that the turbine shaft powers of the SCPP and WSSCPP were reduced by 22.4%and 13.7%,respectively,when the incident angle increased from 0°to 30°.In conclusion,it is important to consider the chimney shadow effect when estimating the performance in the design and cost analysis of SCPP systems.

Airway pressure release ventilation forin-vivodonor lung management and lung transplant outcomes

Background:Airway pressure release ventilation(APRV)can be used for cadaveric donor lung recruitment.APRV elevates PaO_(2)in donor lungs;however,reported outcomes in recipients with APRVmanaged donor lungs are limited.Methods:We retrospectively reviewed patients who underwent lung transplantation(LTx)from 2012 to 2013 and divided them into two groups based on mode of ventilation used during donor management and organ extraction(A:non-APRV;B:APRV).Kaplan-Meier method and multivariate Cox regression were used for analysis.Results:We found 126 LTx recipients(LTxRs);9 were excluded for use of portable ventilation perfusion systems.Of the remaining 117 patients,81(69%)were in Group A;36(31%)were in Group B.Preoperative LTxR characteristics(age,sex,lung allocation score,endstage lung disease type)were comparable between groups.Donors for Group B were older(P=0.03)and had higher body mass index(BMI)(P<0.001),higher incidence of death from chest trauma(P=0.008),longer ventilation duration after brain death(P<0.001),and higher pre-explant PaO_(2)/FiO_(2)ratios(P<0.001).Post-LTx duration of mechanical ventilation,hospital stay,and median survival were similar in both groups.Risk of death was comparable between the two groups at the end of follow-up(HR=1.42;95%CI:0.57-3.56;P=0.45).Conclusions:APRV is a safe and effective pre-LTx donor lung management strategy.Short-and long-term survival outcomes were comparable in LTx recipients,irrespective of donor ventilation mode.APRV may help recruit lungs from older donors with higher BMI who die from chest trauma and have anticipated longer ventilation duration.

Effects of extrinsic positive end-expiratory pressure on cardiopulmonary function in patients with chronic obstructive pulmonary disease

Objective To choose one optimal extrinsic positive end-expiratory pressure (PEEPe) for ventilated patients with chronic obstructive pulmonary disease (COPD) and to compare two methods for choosing the optimal level of PEEPe.Methods Ten ventilated patients with COPD were included in the study. First, static intrinsic positive end-expiratory pressure (PEEPi,st) was measured when PEEPe was zero, and the PEEPi,st was called PEEPi,stz. PEEPe at 0%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of PEEPi,stz, respectively, were applied randomly. Respiratory mechanics, hemodynamics, and oxygen dynamics were recorded 30 minutes after the level of PEEPe was changed.Results When PEEPe was not higher than 80% of PEEPi,stz, no measurement changed significantly. When PEEPe was increased to 90% and 100% of PEEPi,stz, PEEPi,st, peak inspiratory pressure, plateau pressure, pulmonary capillary wedge pressure and central venous pressure increased significantly, P<0.01. Cardiac output and left ventricular work index decreased significantly, P<0.01. Oxygen delivery decreased significantly, P<0.05. When PEEPe was increased to 100% of PEEPi,stz, the right ventricular work index decreased significantly, P<0.05.Conclusion Eighty percent of PEEPi,stz was the upper limit of PEEPe. The results of the two methods used to set the level of PEEPe were identical.