Objective To evaluate the effect of auto adjusted triggering mechanism on the triggering balance of sensitivity and anti-interference in non invasive ventilator field. Methods Taking the breathing simulator as the experimental platform, for the same ventilator, the experiments of "automatic adjustment mode" and "manual adjustment mode" were carried out in a self-control manner, comparing the sensitivity and anti-interference indexes of the experimental group and the control group in the triggering stage. The results were statistically analyzed. Results In case of large air leakage, for ventilator of "A40", the group of "automatic adjustment mode" presented auto-triggered cycle and the group of "manual adjustment mode" (the inspiratory trigger sensitivity was adjusted to 5 to 9 L/min) could provide breathing assistance ventilation. While for ventilator of "VENT", both the group of "automatic adjustment mode" and the group of "manual adjustment mode" (the inspiratory trigger sensitivity was adjusted to 1 to 8 arbitrary unit) appear auto-triggered cycle. In case of medium air leakage, for ventilator of "A40", the trigger delay time, trigger pressure and trigger work of the "manual adjustment mode" group (the inspiratory trigger sensitivity was adjusted to 3 to 5 L/min) were significantly less than those of the "automatic adjustment mode" group, and the trigger delay time, trigger work of the "manual adjustment mode" group (the inspiratory trigger sensitivity was adjusted to 8 to 9 L/min) were significantly higher than those of the "automatic adjustment mode" group; While for ventilator of "VENT", compared with the inspiratory trigger sensitivity of the "automatic adjustment mode" group and the "manual adjustment mode" group (the inspiratory trigger sensitivity was adjusted to 4 arbitrary unit), the trigger delay time, trigger pressure and trigger work were not statistically significant. In case of small air leakage, for ventilator of "A40", the trigger delay time and trigger work of the "manual adjustment mode" group (the inspiratory trigger sensitivity was adjusted to 2 to 6 L/min) were significantly less than those in the "automatic adjustment mode" group, and the trigger pressure of "manual adjustment mode" group (the inspiratory trigger sensitivity was adjusted to 2 to 5 L/min and 7 L/min) was significantly lower than that of "automatic adjustment mode" group. While for ventilator of "VENT", the trigger delay time, trigger pressure and trigger work of the "manual adjustment" group (the inspiratory trigger sensitivity was adjusted to 1 to 2 arbitrary unit) were less than those of the experimental group, and they were statistically significant. Conclusions In case of large air leakage, ventilator of "VENT" can not provide breathing assistance ventilation no matter which inspiratory trigger mode. While ventilator of "A40" should be used the "manual adjustment mode", and adjust the inspiratory trigger sensitivity to the less sensitive arbitrary unit to increase its performance of anti-interference. In case of medium air leakage, for both ventilator of "A40" and ventilator of "VENT", it is better to use "automatic adjustment" mode for breathing assistance ventilation. In case of small air leakage, for both ventilator of "A40" and ventilator of "VENT", it is better to use "manual adjustment" mode for breathing assistance ventilation and we should adjust the inspiratory trigger sensitivity to the higher sensitive arbitrary without auto-triggered cycle.
Objective To systematically evaluate the efficacy of home noninvasive positive pressure ventilation (HNPPV) on patients with severe stable chronic obstructive pulmonary disease in China. Methods Systematic literature search was performed in Chinese BioMedical Literature Database, WanFang Data, VIP Database, Chinese National knowledge Infrastructure databases from inception to January 2018. All randomized controlled trials (RCTs) that reported comparison of the efficacy of HNPPV on patients with severe stable chronic obstructive pulmonary disease were included. All related data were extracted. Meta-analysis was conducted using the statistical software RevMan 5.3 on the basis of strict quality evaluation. Results A total of 767 patients from 14 studies were included in this meta-analysis. The combined results showed that, compared with the control group, HNPPV could significantly reduce the mortality (relative risk 0.51, 95%CI 0.33 – 0.78, P=0.002) and PaCO2 ［weighted mean difference (MD) –10.78, 95%CI –13.17 – –8.39, P<0.000 01］ of patients, improve the levels of PaO2 (MD 7.84, 95%CI 5.81 – 9.87, P<0.000 01), FEV1 (MD 0.13, 95%CI 0.08 – 0.18, P<0.000 01), and the quality of life (MD –6.27, 95% CI –9.04 – –3.51, P<0.000 01). Conclusion HNPPV can reduce the mortality of patients, improve the gas exchange, pulmonary function and the quality of life, but more large sample, high-quality, and multicenter RCT studies are needed.
Objective This is a meta-analysis of the efficacy of noninvasive ventilation (NIV) with helmet compared to NIV with face mask in patients with acute respiratory failure (ARF). Methods " Helmet, face mask or facial mask” and " mechanical ventilation or noninvasive ventilation” were used as key words both in Chinese and English to search all the trials in PubMed, OVID, Embase, Scopus and Cochrane Library, websites, reference lists of articles, CNKI and Wanfang Database from inception to December 2016. Two reviewers independently assessed the methodological quality of the trials and extracted information. Revman 5.3 was used for data analysis. Results Ten randomized controlled trials (RCTs) and six case-control trials were included. NIV with a helmet reduced the intubation rate (OR=0.35, 95%CI 0.24 to 0.51, P<0.000 01), in-hospital mortality rate (OR=0.51, 95%CI 0.34 to 0.76, P=0.001), and NIV-related complications (OR=0.10, 95%CI 0.06 to 0.15, P<0.000 01) compared to NIV with face mask. There was no significant difference in gas exchange between two groups. In the subgroup analysis, types of ARF and ventilation mode did not affect the intubation rate and the complications relevant to NIV, but NIV with helmet mainly decreased the in-hospital mortality of the patients with hypoxemic ARF or pressure support ventilation. Conclusions NIV with a helmet can decrease the endotracheal intubation rate, in-hospital mortality, and NIV-related complications of the patients with ARF. And helmet is as effective as face mask in improving the gas exchange. However, larger or multicenter RCTs are needed to analyze the role of NIV with a helmet in this condition.
Objective To evaluate the influence on the estimation of respiratory mechanics with dynamic signal analysis approach during noninvasive positive pressure ventilation (NPPV) under different inspiratory effort conditions. Methods The Respironics V60 ventilator was connected to a ASL5000 lung simulator, which simulate lung mechanics in healthy adults with body weight from 65 to 70 kg, and patients with chronic obstructive pulmonary disease (COPD) and acute respiratory distress (ARDS). Each lung models was subjected to 4 different muscle pressures (Pmus): 0, 5.0, 10.0, and 15.0 cm H2O. Inspiratory pressure support level was adjusted to maintain tidal volume (VT) achieving 7.0 mL/kg outputted by ventilator respectively. Positive end expiratory pressure was set at 5.0 cm H2O and back-up rate was 10 beats per minute. Measurements were conducted at system leaks with 25 to 28 L/min. The respiratory system compliance (Crs), inspiratory and expiratory resistance (Rinsp and Rexp) were estimated by special equations, which was derived from the exhaled VT, flow rate and airway pressure. Results The driving pressure (DP) was decreased with Pmus increasing, and was 1.0 cm H2O after Pmus exceeding 10.0 cm H2O and the VT was larger than 7.0 mL/kg in normal adult model. The estimated value of Crs was affected by the changes of Pmus in all three lung models. The significant underestimation of Raw and the overestimation of Crs were observed when Pmus level exceed 10.0 cm H2O. The measured errors of Crs and Rexp were within 10% in COPD and ARDS model when Pmus was at 5.0 cm H2O. The underestimation of Rinsp was always existed in all Pmus level (P<0.01). Conclusions Using dynamic signal analysis approach, the real-time estimation of respiratory mechanics (Crs and Raw) is no need to interrupt the spontaneous breathing during NPPV. Excessive effort will increase the patient’s inspiratory workload, which is not benefit to accurate estimation of respiratory mechanics.
ObjectiveTo investigate whether noninvasive positive pressure ventilation (NIV) will improve preoxygenation in critically ill patients in intensive care unit (ICU) before intubation, when compared with bag-valve-mask (BVM).MethodsThis was a single-centered, prospective and randomized study. The patients in the study were those who required tracheal intubation in the ICU of the First Affiliated Hospital of Guangzhou Medical University and Guangzhou Institute of Respiratory Health from June 2015 to June 2017. These critically ill patients were provided with BVM or NIV assisted preoxygenation randomly. The data of the NIV group and the control group were compared and the application values of NIV in preoxygenation of critically ill patients were evaluated.ResultsA total of 106 patients participated in this study, including 75 males and 31 females and with an average age of (65.0±12.6) years. The patients were classified either into the control group (BVM assisted preoxygenation, n=53), or the NIV group (NIV assisted pre-oxygenation, n=53). The causes of intubation in the control group and the NIV group were as follows: pneumonia [40 patients (75.5%) vs. 39 patients (73.6%)], chronic obstructive pulmonary disease [12 patients (22.6%) vs. 11 patients (20.8%)], and other disease [1 patient (1.9%) vs. 3 patients (5.7%)], which showed no significant difference between the two groups. The scores of the Acute Physiology and Chronic Health Evaluation System Ⅱ of the control group and the NIV group were 20 (17, 26) vs. 20 (16, 26), P=0.86, which also showed no significant difference. The oxygen saturation of the pulse (SpO2) before preoxygenation were similar in both the control group and the NIV group 92% (85%, 98%) vs. 91% (85%, 98%), P=0.87. After preoxygenation, SpO2 was significantly higher in the NIV group than in the control group 99% (96%, 100%) vs. 96% (90%, 99%), P=0.001. For the subgroup of patients with SpO2 less than 90% before preoxygenation, the respective SpO2 in the control group and the NIV group were 83% (73%, 85%) vs. 81% (75%, 86%), P=0.75; after preoxygenation, SpO2 in the NIV group was significantly higher than in the control group 99% (96%, 100%) vs. 94%(90%, 99%), P=0.000. For the subgroup of patients with SpO2 of 90% or more before preoxygenation, the respective SpO2 in the control group and the NIV group were similar 95.5% (92%, 99%) vs. 96% (94%, 99%), P=0.52; and continued to be similar after preoxygenation 98% (95%, 100%) vs. 99% (96%, 100%), P=0.1. The duration of mechanical ventilation of the control group and the NIV group was 17 (10, 23)d vs. 19 (11, 26)d (P=0.86). The 28 days survival rate of the control group and the NIV group was 73.6% vs. 71.7% (P=0.34). The mortality rate in the control group and NIV group were 31.3% and 31.7% (P=0.66).ConclusionsWhen compared with the use of BVM, NIV assisted preoxygenation is effective and safe for critically ill patients. Critically ill patients with severe hypoxemia will benefit more from NIV assisted preoxygenation.
ObjectiveTo investigate the clinical characteristics of polymyositis (PM)/dermatomyositis (DM) with acute interstitial pneumonia (AIP) as the presenting symptoms, and identify characteristics of such disease. MethodsA retrospective analysis was conducted on the hospitalized patients with PM/DM with AIP as the presenting symptoms, from October 2009 to June 2015 in the Departemnt of Respiratory Medicine, Guangzhou Institute of Respiratory Diseases. ResultsThey were two males and six females with a mean age of 54.8±7.5 years. The common clinical features included fever (8 cases), shortness of breath (8 cases), rapidly progressive exertional dyspnea (8 cases), dry cough (6 cases), decreased muscle strength (8 cases), and typical rash (7 cases). Electromyography showed neurogenic or myogenic leision in these 8 cases. Muscle biopsy revealed myositis in 7 cases. High resolution CT (HRCT) revealed widespread ground glass patterns in all patients. All patients received noninvasive positive pressure mechanical ventilation on the first hospital day. High dose of methylprednisolone or combination with intravenous cyclophosphamide were initiated on 2.3±1.4 hospital day. Six patients survived to hospital discharge and two patient died. ConclusionsThe most common symptoms in patients of PM/DM with AIP are shortness of breath, progressive exertional dyspnea, and dry cough. Typical rash is seen in most of the patients.The diagnosis can be established by combinating the characteristics of HRCT, electromyography and muscle biopsy. Earlier intervention with noninvasive positive pressure mechanical ventilation and immunosuppressive may improve clinical outcome in patients of PM/DM with AIP.
Objective To explore the effects of enteral tube feeding on moderate AECOPD patients who underwent noninvasive positive pressure ventilation ( NPPV) . Methods Sixty moderate AECOPD patients with NPPV admitted from January 2009 to April 2011 were recruited for the study. They were randomly divided into an enteral tube feeding group (n=30) received enteral tube feeding therapy, and an oral feeding group (n=30) received oral feeding therapy. Everyday nutrition intake and accumulative total nutrition intake in 7 days, plasma level of prealbumin and transferrin, success rate of weaning, duration of mechanical ventilation, length of ICU stay, rate of trachea cannula, and mortality rate in 28 days were compared between the two groups. Results Compared with the oral feeding group, the everyday nutrition intake and accumulative total nutrition intake in 7 days obviously increased (Plt;0.05) , while the plasma prealbumin [ ( 258.4 ±16.5) mg/L vs. (146.7±21.6) mg/L] and transferrin [ ( 2.8 ±0.6) g/L vs. ( 1.7 ±0.3) g/L] also increased significantly after 7 days in the enteral tube feeding group( Plt;0.05) . The success rate of weaning ( 83.3% vs. 70.0%) , the duration of mechanical ventilation [ 5. 6( 3. 2-8. 6) days vs. 8. 4( 4. 1-12. 3) days] , the length of ICU stay [ 9. 2( 7. 4-11. 8) days vs. 13. 6( 8.3-17. 2) days] , the rate of trachea cannula ( 16. 6% vs. 30. 0% ) , the mortality rate in 28 days ( 3. 3% vs. 10. 0% ) all had significant differences between the enteral tube feeding group and the oral feeding group. Conclusions For moderate AECOPD patients with NPPV, enteral tube feeding can obviously improve the condition of nutrition and increase the success rate of weaning, shorten the mechanical ventilation time and the mean stay in ICU, decrease the rate of trachea cannula and mortality rate in 28 days. Thus enteral tube feeding should be preferred for moderate AECOPD patients with NPPV.
Most of the existing near-infrared noninvasive blood glucose detection models focus on the relationship between near-infrared absorbance and blood glucose concentration, but do not consider the impact of human physiological state on blood glucose concentration. In order to improve the performance of prediction model, particle swarm optimization (PSO) algorithm was used to train the structure paramters of back propagation (BP) neural network. Moreover, systolic blood pressure, pulse rate, body temperature and 1 550 nm absorbance were introduced as input variables of blood glucose concentration prediction model, and BP neural network was used as prediction model. In order to solve the problem that traditional BP neural network is easy to fall into local optimization, a hybrid model based on PSO-BP was introduced in this paper. The results showed that the prediction effect of PSO-BP model was better than that of traditional BP neural network. The prediction root mean square error and correlation coefficient of ten-fold cross-validation were 0.95 mmol/L and 0.74, respectively. The Clarke error grid analysis results showed that the proportion of model prediction results falling into region A was 84.39%, and the proportion falling into region B was 15.61%, which met the clinical requirements. The model can quickly measure the blood glucose concentration of the subject, and has relatively high accuracy.
ObjectiveTo systematically review the effectiveness and safety of interventions which target to improve the rate of successful extubation in preterm infants.MethodsPubMed, Web of Science, Cochrane Library, Chongqing VIP database, China National Knowledge Infrastructure, and Wanfang Database were searched for articles published from the dates of establishment of databases to August 2020, which compared different noninvasive respiratory support models or different doses of caffeine to improve the rate of successful extubation in preterm infants in randomized controlled trials. The references of included articles were also retrieved. And then a meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 33 randomized controlled trials involving 4 536 preterm infants were included. Compared with nasal continuous positive airway pressure (NCPAP), high-flow nasal cannula (HFNC) reduced the nose injury rate [odds ratio (OR)=0.29, 95% confidence interval (CI) (0.15, 0.57), P=0.000 3] and the pneumothorax rate [OR=0.18, 95%CI (0.06, 0.55), P=0.003]; nasal intermittent positive pressure ventilation (NIPPV) reduced the extubation failure rate [OR=0.33, 95%CI (0.23, 0.48), P<0.000 01], the reintubation rate [OR=0.36, 95%CI (0.20, 0.65), P=0.000 7], the respiratory failure rate [OR=0.33, 95%CI (0.17, 0.64), P=0.000 9], and the pneumothorax rate [OR=0.29, 95%CI (0.12, 0.70), P=0.006]; and biphasic positive airway pressure (BiPAP) reduced the reintubation rate [OR=0.21, 95%CI (0.09, 0.46), P=0.000 1]. Compared with low-dose caffeine, high-dose caffeine reduced the extubation failure rate [OR=0.44, 95%CI (0.32, 0.60), P<0.000 01] and the bronchopulmonary dysplasia rate [OR=0.69, 95%CI (0.48, 0.99), P=0.04], but increased the rate of tachycardia [OR=1.99, 95%CI (1.22, 3.25), P=0.006].ConclusionAccording to the current evidence, compared with NCPAP, NIPPV and BiPAP could be used to improve the rate of successful extubation in preterm infants, HFNC could be used to decrease the risk of nose injury and pneumothorax; the optimal dose of caffeine should be chosen after evaluating the risk of adverse reactions such as tachycardia.
Objective To investigate the effects of noninvasive ventilation for the treatment of acute respiratory failure secondary to severe acute respiratory syndrome ( SARS) . Methods 127 patients with complete information were collected from the database of SARS in Guangdong province, who were all consistent with the ALI/ARDS diagnostic criteria. The patients were divided into three groups depending on ventilation status, ie. a no-ventilation group, a noninvasive ventilation group, and a mechanical ventilation group. The outcome of ventilation treatmentwas followed up.Multi-factor regression analysis was conducted to analyze the relations of ventilation treatment with ARDS and mortality, and factors associated with success of noninvasive ventilation. Results As soon as the patients met the diagnostic criteria of ALI/ARDS, the patients in the noninvasive ventilation group were in more serious condition and had a higher proportion of ARDS compared with the no-ventilation group ( P lt;0. 01) . The patients in the mechanical ventilation group had a higher mortality rate ( P lt;0.01) . 6 and 7 patients in the no-ventilation group had noninvasive ventilation and invasive ventilation thereafter, respectively. 15 patients in the noninvasive group switched to invasive ventilation. Compared with the patients without ventilation ( n =45) , the patients receiving noninvasive ventilation ( n = 61) were in more serious condition and at higher risk of developing ARDS ( P lt;0. 01) , but the mortality was not different between them ( P gt; 0. 05) . The patients who continued to receive noninvasive ventilation ( n = 40) were in more serious condition, and at higher risk of developing ARDS compared with the patients without ventilation ( n = 45) ( P lt; 0. 01) . 15 patients in the noninvasive group who switched to invasive ventilation were older than those patients continuing noninvasive ventilation.Conclusions For SARS patients fulfilling the ALI/ARDS criteria, the patients underwent noninvasive ventilation are more severe, run a higher probability of developing ARDS from ALI. But earlier initiation of noninvasive ventilation has no impact on mortality. The patients who tolerate noninvasive ventilation can avoid intubation, especially for young patients. However, the time and indication of shifting from noninvasive ventilation to invasive ventilation should be emphasized.