Objective To investigate the effects of different inspiratory rise time during noninvasive positive pressure ventilation ( NPPV) on work of breathing in patients with acute exacerbation of chronic obstructive pulmonary disease ( COPD) . Methods Eleven patients with acute exacerbation of COPD received different inspiratory rise time ( 0. 1sec, 0. 3sec, 0. 5sec) during NPPV. The changes of inspiratory muscle effort and breathing pattern of the patients were observed. Results The average respiratory rate,minute ventilation, and tidal volume were higher during NPPV compared with spontaneous breathing. But the changes of average minute ventilation and tidal volume were not significant ( P gt; 0. 05) . The pressure time product ( PTP) , transdiaphragmatic pressure ( Pdi) , and work of breathing of inspiratory muscle reduced significantly during different inspiratory rise time as compared with spontaneous breathing ( P lt;0. 01) . PTP,Pdi, and work of breathing reduced 59. 2% , 62. 7% , and 49% respectively when inspiratory rise time was 0. 1sec. They reduced more significantly during inspiratory rise time of 0. 1sec. Conclusions The present study confirms NPPV can unload inspiratory muscles in patients with acute exacerbation of COPD. It is more effective to reduce inspiratory load when inspiratory rise time is set at 0. 1sec while the patients feel most comfortable.
Objective To investigate the effects of noninvasive positive pressure ventilation (NPPV) on patients with acute left heart failure. Methods Twenty patients with acute left heart failure diagnosed between September 2013 and July 2014 were randomized into treatment group (n=10) and control group (n=10). Both groups used conventional sedations, diuretics and drugs that strengthened the heart and dilated the vessels, while early use of NPPV was applied in the experimental group. Arterial blood gas analysis [pH value, pressure of arterial carbon dioxide (PaCO2), and pressure of arterial oxygen (PaO2)], heart rate (HR), respiration, duration of Intensive Care Unit (ICU) stay and invasive mechanical ventilation, duration of overall mechanical ventilation, and success case numbers before and two hours after treatment were observed and analyzed. Results For the control group, two hours after treatment, PaO2 was (67.0±8.5) mm Hg (1 mm Hg=0.133 kPa), HR was (124±10) times/min, Respiration was (34±4) times/min, the duration of ICU stay was (6.0±1.1) days, invasive ventilation was for (32.0±3.1) hours, and the total time of mechanical ventilation was (32.0±3.1) hours. Those indexes for the treatment group two hours after treatment were: PaO2, (82.3±8.9) mm Hg; HR, (98±11) times/min; respiration, (24±4) times/min; the duration of ICU stay, (4.0±0.8) days; invasive ventilation time, (16.0±1.3) hours; the total time of mechanical ventilation, (26.0±1.8) hours. All the differences for each index between the two groups were statistically significant (P < 0.05). Conclusion Early application of NPPV can rapidly relieve clinical symptoms and reduce the medical cost for patients with acute left heart failure.
ObjectiveTo assess the mortality, acute exacerbations, exercise capacity, symptoms and significant physiological parameters (lung function, respiratory muscle function and gas exchange) of patients with severe stable chronic obstructive pulmonary disease (COPD) with respiratory failure treated by noninvasive positive pressure ventilation (NPPV).MethodsA meta-analysis of randomized controlled trials was carried out by searching PubMed, Cochrane library, Embase, OVID, Chinese Biomedical Literature Database and the bibliographies of the retrieved articles up to February 2017. Studies of patients with severe stable COPD with respiratory failure receiving long-term noninvasive positive pressure ventilation and comparison with oxygen therapy were conducted, and at least one of the following parameters were reviewed: frequency of acute exacerbations, mortality, lung function, respiratory muscle function, gas exchange, 6-minute walk test.ResultsSix studies with 695 subjects met the inclusion criteria and were analyzed. The PaCO2 was significantly decreased in patients who received long-term NPPV. No significant difference was found between long-term NPPV and oxygen therapy in mortality, frequency of acute exacerbations, gas exchange, lung function, respiratory muscle function and exercise capacity. The subgroup analysis showed that NPPV improves survival of patients when it is targeted at greatly reducing hypercapnia.ConclusionCurrent evidence suggests that there is no significant improvement by application of NPPV on severe stable COPD with respiratory failure patients, but NPPV may reduce patients’ mortality with the aim of reducing hypercapnia.
Objective To determine the efficacy and prognosis of noninvasive positive pressure ventilation (NPPV) in exacerbations of chronic obstructive pulmonary disease (COPD). Methods Trials were located through electronic searches of MEDLINE, EMBASE, Springer, and Foreign Journals Integration System (from the start date to March 2008). We also checked the bibliographies of retrieved articles. Statistical analysis was performed with The Cochrane Collaboration’s software RevMan 4.2.10. Results A total of 19 trials involving 1 236 patients were included. Results showed that: (1) NPPV vs. conventional therapy: NPPV was superior to conventional therapy in terms of intubation rate (RR 0.36, 95%CI 0.27 to 0.49), failure rate (RR 0.62, 95%CI 0.43 to 0.90), and mortality (RR 0.49, 95%CI 0.34 to 0.69). The length of hospital stay was shorter in the NPPV group compared with the conventional group (WMD – 3.83, 95%CI – 5.78 to – 1.89), but the length of ICU stay was similar. The changes of PaO2, PaCO2, and pH were much more obvious in the NPPV group compared with the conventional group. The change of respiratory rate was more significant in the NPPV group compared with the conventional group (WMD – 3.75, 95%CI – 5.48 to – 2.03). At discharge and follow-up, there were no significant differences in FEV1, pH, PaCO2, PaO2, and vital capacity between the two groups. (2) NPPV vs. invasive ventilation: the mortality was similar between the two groups. The incidence of complications was lower in the NPPV group compared with the invasive group (RR 0.38, 95%CI 0.20 to 0.73). The length of ICU stay, duration of mechanical ventilation, and weaning time were shorter in the NPPV group than those of the invasive group. At discharge and follow-up, clinical conditions were similar between the two groups. Conclusion The limited current evidence showed that NPPV was superior to conventional therapy in improving intubation rate, mortality, short term of blood-gas change, the change of respiratory rate; and superior to invasive ventilation in the length of hospital stay and the incidence of complication. There were no difference among them in discharge and follow-up.
ObjectiveTo investigate the value of noninvasive positive pressure ventilation in patients with high risk of weaning induced pulmonary oedema.MethodsFrom June 2018 to June 2019, 63 patients with mechanical ventilation in the Department of Critical Care Medicine of the First Hospital of Lanzhou University were enrolled. Randomized digital table method was randomly divided into two groups and the resulting random number assignment was hidden in opaque envelopes, the experimental group received non-invasive positive pressure ventilation (n=32), and the control group received mask oxygen therapy ventilation (n=31). The heart rate, respiratory rate, means arterial pressure, hypoxemia, reintubation, blood gas analysis and other indicators were compared between the two groups after 2 hours of weaning. The length of hospital stay, mortality and complications were compared between the two groups.ResultsAfter 2 hours of weaning, the heart rate and respiratory rate were significantly lower in the non-invasive positive pressure ventilation group than in the mask group (P<0.05). There was no difference in mean arterial pressure between the two groups of patients, which was not statistically significant (P>0.05). The incidence of hypoxemia, laryngeal edema and reintubation in the noninvasive positive pressure ventilation group was significantly lower than that in the mask group, which was statistically significant (P<0.05), and the blood gas analysis index was better than the mask group (P<0.05). The non-invasive positive pressure ventilation group was significantly shorter than the mask group in the length of hospital stay and intensive care unit (P<0.05). The hospital mortality rate in 28 days was lower than that in the mask group (P<0.05), but there was no difference in tracheotomy, pneumothorax and subcutaneous emphysema between the two groups (P>0.05).ConclusionsNoninvasive positive pressure ventilation can effectively prevent hypoxemia, laryngeal edema, and re-intubation in patients at high risk of withdrawal related pulmonary edema. It can also shorten the length of hospital stay, which is worth clinical attention and promotion.
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.
Objective The risk factors of noninvasive positive pressure ventilation (NPPV) in the treatment of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) combined with failure of respiratory failure were identified by meta-analysis, so as to provide a basis for early clinical prevention and treatment failure and early intervention. Methods PubMed, The Cochrane Library, EMbase, China National Knowledge Infrastructure, Wanfang, VIP and CBM Data were searched to collect studies about risk factors about failure of noninvasive positive pressure ventilation in AECOPD and respiratory failure published from January 2000 to January 2021. Two researchers independently conducted literature screening, literature data extraction and quality assessment. Meta-analysis was performed on the final literature obtained using RevMan 5.3 software. Results Totally 19 studies involving 3418 patients were recruited. The statistically significant risk factors included Acute Physiology and Chronic Health Evaluation (APACHEⅡ) score, pre-treatment PCO2, pre-treatment pH, Glasgow Coma Scale (GCS), respiratory rate (RR) before treatment, body mass index (BMI), age, C-reactive protein (CRP), renal insufficiency, sputum disturbance, aspiration of vomit. Conclusions High APACHE-Ⅱ score, high PCO2 before treatment, low pH value before treatment, low GCS score, high RR before treatment, low BMI, advanced age, low albumin, high CRP, renal insufficiency, sputum disturbance, and vomit aspiration were the risk factors for failure of respiratory failure in patients with COPD treated by NIPPV. Failure of non-invasive positive pressure ventilation in COPD patients with respiratory failure is affected by a variety of risk factors, and early identification and control of risk factors is particularly important to reduce the rate of treatment failure.
Objective To study the effect of noninvasive positive pressure ventilation (NPPV) in chronic obstructive pulmonary disease (COPD) patients with hypercapnic coma secondary to respiratory failure.Methods COPD patients with or without coma secondary to respiratory failure were both treated by bi-level positive airway pressure (BiPAP) ventilation on base of routine therapy.There were 32 cases in coma group and 42 cases in non-coma group.Such parameters as arterial blood gas (ABG)，Glasgow coma scale (GCS)，time of NPPV therapy，achievement ratio，and adverse effects were investigated.Results 30 patients in the coma group were improved after NPPV treatment (26 cases recovered consciousness treated by BiPAP in 2 hours，3 cases recovered between 3~8 hours，1 case recovered after 24 hours).The parameters of ABG，the tidal volume and the minute ventilation volume were improved after BiPAP.The time of effective therapy was (9±4) days in the coma group and (7±3) days in the non-coma group with no significant difference (Pgt;0.05).The achievement ratio was similar in two groups (93.75% vs 97.62%，Pgt;0.05).But the incidence of gastrointestinal tympanites reached to a higher level in the coma group (80.5%) than the non-coma group (10.6%).Conclusion COPD patients with hypercapnic coma secondary to respiratory failure isn’t the absolute contraindication of NPPV treatment.
Objective To analyze the risk factors of treatment failure by noninvasive positive pressure ventilation (NPPV) in patients with acute respiratory failure (ARF) due to acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and explore the best time that NPPV be replaced by invasive ventilation when NPPV failure occurs. Methods The data of patients with ARF due to AECOPD who were treated with NPPV from January 2013 to December 2015 were retrospectively collected. The patients were divided into two groups: the NPPV success group and the NPPV failure group (individuals who required endotracheal intubation or tracheotomy at any time). The Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ score was analyzed; the Glasgow Coma Scale score, respiratory rate (RR), pH value, partial pressure of oxygen (PaO2), PaO2/fraction of inspired oxygen (FiO2) ratio, and partial pressure of carbon dioxide were also analyzed at admission, after 2 hours of NPPV, and after 24 hours of NPPV. Results A total of 185 patients with ARF due to AECOPD were included. NPPV failed in 35.1% of the patients (65/185). Multivariate analysis identified the following factors to be independently associated with NPPV failure: APACHEⅡscore≥30 [odds ratio (OR)=20.603, 95% confidence interval (CI) (5.309, 80.525), P<0.001], RR at admission≥35 per minute [OR=3.723, 95%CI (1.197, 11.037), P=0.020], pH value after 2 hours of NPPV<7.25 [OR=2.517, 95%CI (0.905, 7.028), P=0.070], PaO2 after 2 hours of NPPV<60 mm Hg (1 mm Hg=0.133 kPa) [OR=3.915, 95%CI (1.374, 11.508), P=0.010], and PaO2/FiO2 after 2 hours of NPPV<200 mm Hg [OR=4.024, 95%CI (1.542, 11.004), P=0.010]. Conclusion When patients with ARF due to AECOPD have a higher severity score, have a rapid RR at admission, or fail to improve in terms of pH and oxygenation after 2 hours of NPPV, the risk of NPPV failure is higher.
Objective To investigate the physiological effects of different oxygen injection site on ventilatory status and oxygenation during noninvasive positive pressure ventilation ( NPPV) with portable noninvasive ventilators. Methods A prospective crossover randomized study was performed. Oxygen injection site was randomized into the outlet of the ventilator, the connection site between mask and circuit, and the mask under the condition of leak port immobilized in the mask. Oxygen flow was retained in the baseline level at the initial 5 to 10 minutes, and adjusted to obtain arterial oxygen saturation measured by pulse oximetry ( SpO2 ) ranging from 90% to 95% after SpO2 remains stable. SpO2 at the initial 5 to 10 minutes, oxygen flow, ventilatory status, oxygenation, hemodynamics and dyspnea indexes at0. 5 hour, 1 hour, and 2 hours of NPPV were compared between different oxygen injection sites. Results 10 patients were recruited into the study. Under the condition of the same oxygen flow, SpO2 with oxygen injection site in the outlet of the ventilator was significantly higher than that with oxygen injection site in the connection site between mask and circuit [ ( 98.9 ±0.9) % vs. ( 96.9 ±1.1) % , P =0. 003] , whereas SpO2 with oxygen injection site in the connection site between mask and circuit was significantly higher than that with oxygen injection site in the mask [ ( 96.9 ±1.1) % vs. ( 94.1 ±1.6) %, P = 0.000] . Oxygen flow with oxygen injection site in the mask was statistically higher than that with oxygen injection site at other sites ( P lt; 0.05) . Arterial oxygen tension/ oxygen flow with oxygen injection site in the outlet of the ventilator was significantly higher than that with oxygen injection site in the connection site between mask and circuit ( 67.9 ±31.1 vs. 37.0 ±15.0, P =0.007) , and than that with oxygen injection site in the mask ( 67.9 ± 31.1 vs. 25.0 ±9.1, P = 0.000) . pH, arterial carbon dioxide tension, hemodynamics and dyspnea indexes were not significantly different between different oxygen injection sites ( P gt; 0.05) .Conclusions When portable noninvasive ventilator was applied during NPPV, oxygen injection site significantly affects improvement of oxygenation, and shows a trend for affecting ventilatory status and work of breathing. When the leak port was immobilized in the mask, the nearer oxygen injection site approaches the outlet of the ventilator, the more easily oxygenation is improved and the lower oxygen flow is demanded.