Noninvasive ventilation in acute respiratory failure

Comparison of the Efficacies of High-Flow Nasal Cannula Oxygen Therapy and Non-invasive Nasal Cannula Ventilation in Preventing Intubation

OBJECTIVE

This study aimed to compare high-flow nasal cannula oxygen therapy (nc-HFOT) and non-invasive nasal cannula ventilation (nc-NIV) in terms of intubation requirements.

MATERIALS AND METHODS

The study was conducted retrospectively on cases followed up in the pediatric intensive care unit (PICU) between October 2019 and December 2021.

RESULTS

Of all cases, 43 (55.8%) were male, and the median age was 16 months. The median PRISM-3 score for all cases was 2.5 (range: 0-3). Among the cases 45 cases (58.4%) received nc-HFOT treatment, and 32 cases (41.6%) received nc-NIV treatment. The median duration of respiratory support for all cases was 2 days, and 14 cases (18.2%) needed intubation. The median PICU stay day for all cases was 7 days, and the median hospital stay day was 11 days. The median age, PICU, and hospital stay days of the nc-NIV group were significantly higher (P < .05). In the logistic regression analysis, the probability of requiring intubation in cases initially nc-NIV was performed was found to be 4.95 times higher than those using nc-HFOT (OR: 4.95, 95% CI: 1.3-18.8, P = 0.01). Additionally, cases with underlying chronic diseases were found to have a 5.9 times increased likelihood of requiring intubation compared to those without (OR: 5.9, 95% CI: 1.41-24.5, P = .01). Five cases (6.5%) were lost during intensive care stay.

CONCLUSION

The application of nc-NIV increases intubation by 4.95 times compared to the application of nc-HFOT. The intubation rate in cases with underlying chronic diseases is also 5.9 times higher than those without.

Helicopter Air Transport of a Patient Using High Flow Nasal Cannula: A Case Report

The classic out-of-hospital approach to a patient with severe acute respiratory failure involves both orotracheal intubation and invasive mechanical ventilation. The use of non-invasive methods for respiratory support has been shown to be beneficial in managing both acute and chronic respiratory failure. However, its use had not been previously considered for air medical transport due to concerns related to airway safety during flight, limited oxygen availability, and limited experience in this setting. We describe the successful inter-hospital helicopter transport of a patient with end-stage lung disease to a transplantation unit while utilizing a high-flow oxygen cannula, which was performed without significant complications. Our successful case report raises the possibility that high-flow nasal cannulas may be safely employed in the management of respiratory failure in specific patient populations during air medical transport.

Effectiveness of high-flow nasal cannulae compared with noninvasive positive-pressure ventilation in preventing reintubation in patients receiving prolonged mechanical ventilation

Many intensive care unit patients who undergo endotracheal extubation experience extubation failure and require reintubation. Because of the high mortality rate associated with reintubation, postextubation respiratory management is crucial, especially for high-risk populations. We conducted the present study to compare the effectiveness of oxygen therapy administered using high-flow nasal cannulae (HFNC) and noninvasive positive pressure ventilation (NIPPV) in preventing reintubation among patients receiving prolonged mechanical ventilation (PMV). This single-center, prospective, unblinded randomized controlled trial was at the respiratory care center (RCC). Participants were randomized to an HFNC group or an NIPPV group (20 patients in each) and received noninvasive respiratory support (NRS) administered using their assigned method. The primary outcome was reintubation within7 days after extubation. None of the patients in the NIPPV group required reintubation, whereas 5 (25%) of the patients in the HFNC group required reintubation (P = 0.047). The 90-day mortality rates of the NIPPV and HFNC groups (four patients [20%] vs. two patients [10%], respectively) did not differ significantly. No significant differences in length of RCC stay, length of hospital stay, time to liberation from NRS, and ventilator-free days at 28-day were identified. The time to event outcome analysis also revealed that the risk of reintubation in the HFNC group was higher than that in the NIPPV group (P = 0.018). Although HFNC is becoming increasingly common as a form of postextubation NRS, HFNC may not be as effective as NIPPV in preventing reintubation among patients who have been receiving PMV for at least 2 weeks. Additional studies evaluating HFNC as an alternative to NIPPV for patients receiving PMV are warranted.ClinicalTrial.gov ID: NCT04564859; IRB number: 20160901R.Trial registration: ClinicalTrial.gov ( https://clinicaltrials.gov/ct2/show/NCT04564859 ).

Rapid Shallow Breathing Index as a Predictor for Intubation and Mortality in Acute Respiratory Failure

BACKGROUND

Noninvasive ventilation (NIV) is one of the most important therapeutic tools in patients with acute respiratory failure. However, in case of incorrect patient selection it can delay necessary intubation and is associated with complications and even mortality. Patient selection, therefore, plays a key role in therapeutic success. The purpose of this study was to determine the value of the rapid shallow breathing index (RSBI) in predicting the failure of NIV.

METHODS

This prospective observational study was conducted in the emergency department (ED) of a tertiary hospital. Adults presenting to the ED with acute respiratory failure were included in the study. The success of RSBI values measured initially (RSBI 1) and at 30 min (RSBI 2) and the difference between these 2 values (Δ RSBI) in predicting subjects' intubation requirement and survival was tested using multivariate logistic regression analysis.

RESULTS

Two hundred sixty-seven subjects were included in the study. RSBI 1, RSBI 2, and Δ RSBI values differed significantly between the intubated and non-intubated subjects. According to the multivariate model, RSBI 1 and RSBI 2 > 105, Δ RSBI < 19, heart rate > 100 beats/min, and S_pO2 < 92% were significantly associated with intubation requirement. RSBI 1, RSBI 2, and Δ RSBI values also differed significantly between subjects with a fatal course and surviving individuals. According to the multivariate model, RSBI 2 > 105, Δ RSBI < 19, heart rate > 100, and increasing age were associated with in-hospital mortality.

CONCLUSIONS

RSBI can be a successful marker in predicting the failure of NIV and predicting in-hospital mortality in patients admitted to the ED with acute respiratory failure.

Non-Invasive Ventilation as a Therapy Option for Acute Exacerbations of Chronic Obstructive Pulmonary Disease and Acute Cardiopulmonary Oedema in Emergency Medical Services

In this observational prospective multicenter study conducted between October 2016 and October 2018, we tested the hypothesis that the use of prehospital non-invasive ventilation (phNIV) to treat patients with acute respiratory insufficiency (ARI) caused by severe acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and acute cardiopulmonary oedema (ACPE) is effective, time-efficient and safe. The data were collected at four different physician response units and three admitting hospitals in a German EMS system. Patients with respiratory failure due to acute exacerbation of chronic obstructive pulmonary disease and acute cardiopulmonary oedema were enrolled. A total of 545 patients were eligible for the final analysis. Patients were treated with oxygen supplementation, non-invasive ventilation or invasive mechanical ventilation. The primary outcomes were defined as changes in the clinical parameters and the in-hospital course. The secondary outcomes included time efficiency, peri-interventional complications, treatment failure rate, and side-effects. Oxygenation under phNIV improved equally to endotracheal intubation (ETI), and more effectively in comparison to standard oxygen therapy (SOT) (paO2 SOT vs. non-invasive ventilation (NIV) vs. ETI: 82 mmHg vs. 125 mmHg vs. 135 mmHg, p-value SOT vs. NIV < 0.0001). In a matched subgroup analysis phNIV was accompanied by a reduced time of mechanical ventilation (phNIV: 1.8 d vs. ETI: 4.2 d) and a shortened length of stay at the intensive care unit (3.4 d vs. 5.8 d). The data support the hypothesis that the treatment of severe AECOPD/ACPE-induced ARI using prehospital NIV is effective, time efficient and safe. Compared to ETI, a matched comparison supports the hypothesis that prehospital implementation of NIV may provide benefits for an in-hospital course.

High-flow nasal cannula versus noninvasive ventilation in patients with COVID-19: a systematic review and meta-analysis

Background:

During the novel coronavirus disease 2019 (COVID-19) pandemic raging around the world, the effectiveness of respiratory support treatment has dominated people’s field of vision. This study aimed to compare the effectiveness and value of high-flow nasal cannula (HFNC) with noninvasive ventilation (NIV) for COVID-19 patients.

Methods:

A comprehensive systematic review via PubMed, Web of Science, Cochrane, Scopus, WHO database, China Biology Medicine Disc (SINOMED), and China National Knowledge Infrastructure (CNKI) databases was conducted, followed by meta-analysis. RevMan 5.4 was used to analyze the results and risk of bias. The primary outcome is the number of deaths at day 28. The secondary outcomes are the occurrence of invasive mechanical ventilation (IMV), the number of deaths (no time-limited), length of intensive care unit (ICU) and hospital stay, ventilator-free days, and oxygenation index [partial pressure of arterial oxygen (PaO₂)/fraction of inhaled oxygen (FiO₂)] at 24 h.

Results:

In total, nine studies [one randomized controlled trial (RCT), seven retrospective studies, and one prospective study] totaling 1582 patients were enrolled in the meta-analysis. The results showed that the incidence of IMV, number of deaths (no time-limited), and length of ICU stay were not statistically significant in the HFNC group compared with the NIV group (ps = 0.71, 0.31, and 0.33, respectively). Whereas the HFNC group performed significant advantages in terms of the number of deaths at day 28, length of hospital stay and oxygenation index (p < 0.05). Only in the ventilator-free days did NIV show advantages over the HFNC group (p < 0.0001).

Conclusion:

For COVID-19 patients, the use of HFNC therapy is associated with the reduction of the number of deaths at day 28 and length of hospital stay, and can significantly improve oxygenation index (PaO₂/FiO₂) at 24 h. However, there was no favorable between the HFNC and NIV groups in the occurrence of IMV. NIV group was superior only in terms of ventilator-free days.

Management of COVID-19-Associated Acute Respiratory Failure with Alternatives to Invasive Mechanical Ventilation: High-Flow Oxygen, Continuous Positive Airway Pressure, and Noninvasive Ventilation

Patients admitted to hospital with coronavirus disease 2019 (COVID-19) may develop acute respiratory failure (ARF) with compromised gas exchange. These patients require oxygen and possibly ventilatory support, which can be delivered via different devices. Initially, oxygen therapy will often be administered through a conventional binasal oxygen catheter or air-entrainment mask. However, when higher rates of oxygen flow are needed, patients are often stepped up to high-flow nasal cannula oxygen therapy (HFNC), continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), or invasive mechanical ventilation (IMV). BiPAP, CPAP, and HFNC may be beneficial alternatives to IMV for COVID-19-associated ARF. Current evidence suggests that when nasal catheter oxygen therapy is insufficient for adequate oxygenation of patients with COVID-19-associated ARF, CPAP should be provided for prolonged periods. Subsequent escalation to IMV may be implemented if necessary.

Bilevel positive airway pressure ventilation for non-COPD acute hypercapnic respiratory failure patients: A systematic review and meta-analysis

The effectiveness of bi-level positive airway pressure (BiPAP) in patients with acute hypercapnic respiratory failure (AHRF) due to etiologies other than chronic obstructive pulmonary disease (COPD) is unclear. To systematically review the evidence regarding the effectiveness of BiPAP in non-COPD patients with AHRF. The Cochrane Library, MEDLINE, EMBASE, and CINAHL Plus were searched according to prespecified criteria (PROSPERO-CRD42018089875). Randomized controlled trials (RCTs) assessing the effectiveness of BiPAP versus continuous positive airway pressure (CPAP), invasive mechanical ventilation, or O₂ therapy in adults with non-COPD AHRF were included. The primary outcomes of interest were the rate of endotracheal intubation (ETI) and mortality. Risk-of-bias assessment was performed, and data were synthesized and meta-analyzed where appropriate. Two thousand four hundred and eighty-five records were identified after removing duplicates. Eighty-eight articles were identified for full-text assessment, of which 82 articles were excluded. Six studies, of generally low or uncertain risk-of-bias, were included involving 320 participants with acute cardiogenic pulmonary edema (ACPO) and solid tumors. No significant differences were seen between BiPAP ventilation and CPAP with regard to the rate of progression to ETI (risk ratio [RR] = 1.49, 95% confidence interval [CI], 0.63-3.62, P = 0.37) and in-hospital mortality rate (RR = 0.71, 95% CI, 0.25-1.99, P = 0.51) in patients with AHRF due to ACPO. The efficacy of BiPAP appears similar to CPAP in reducing the rates of ETI and mortality in patients with AHRF due to ACPO. Further research on other non-COPD conditions which commonly cause AHRF such as obesity hypoventilation syndrome is needed.

Altered expression of microRNAs in the rat diaphragm in a model of ventilator-induced diaphragm dysfunction after controlled mechanical ventilation

BACKGROUND

Ventilator-induced diaphragm dysfunction (VIDD) is a common complication of life support by mechanical ventilation observed in critical patients in clinical practice and may predispose patients to severe complications such as ventilator-associated pneumonia or ventilator discontinuation failure. To date, the alterations in microRNA (miRNA) expression in the rat diaphragm in a VIDD model have not been elucidated. This study was designed to identify these alterations in expression.

RESULTS

Adult male Wistar rats received conventional controlled mechanical ventilation (CMV) or breathed spontaneously for 12 h. Then, their diaphragm tissues were collected for RNA extraction. The miRNA expression alterations in diaphragm tissue were investigated by high-throughput microRNA-sequencing (miRNA-seq). For targeted mRNA functional analysis, gene ontology (GO) analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were subsequently conducted. qRT-PCR validation and luciferase reporter assays were performed. We successfully constructed a model of ventilator-induced diaphragm dysfunction and identified 38 significantly differentially expressed (DE) miRNAs, among which 22 miRNAs were upregulated and 16 were downregulated. GO analyses identified functional genes, and KEGG pathway analyses revealed the signaling pathways that were most highly correlated, which were the MAPK pathway, FoxO pathway and Autophagy-animal. Luciferase reporter assays showed that STAT3 was a direct target of both miR-92a-1-5p and miR-874-3p and that Trim63 was a direct target of miR-3571.

CONCLUSIONS

The current research supplied novel perspectives on miRNAs in the diaphragm, which may not only be implicated in diaphragm dysfunction pathogenesis but could also be considered as therapeutic targets in diaphragm dysfunction.

Predictors of Successful Weaning from Noninvasive Ventilation in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Single-Center Retrospective Cohort Study

Purpose

Noninvasive ventilation (NIV) is often required for patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and it can significantly reduce the need for endotracheal intubation. Currently, there is no standard method for predicting successful weaning from NIV. Therefore, we aimed to evaluate whether a weaning index can predict NIV outcomes of patients with AECOPD.

Methods

This study was conducted at a single academic public hospital in northern Taiwan from February 2019 to January 2021. Patients with AECOPD admitted to the hospital with respiratory failure who were treated with NIV were included in the study. Univariate and multivariate logistic regression analyses were used to identify independent predictors of successful weaning from NIV. Receiver operating characteristic curve methodology was used to assess the predictive capacity.

Results

A total of 85 patients were enrolled, 65.9% of whom were successfully weaned from NIV. The patients had a mean age of 75.8 years and were mostly men (89.4%). The rapid shallow breathing index (RSBI) (P < 0.001), maximum inspiratory pressure (P = 0.014), and maximum expiratory pressure (P = 0.004) of the successful group were significant while preparing to wean. The area under the receiver operating characteristic curve for the RSBI was 0.804, which was considered excellent discrimination.

Conclusion

The RSBI predicted successful weaning from NIV in patients with AECOPD with hypercapnic respiratory failure. This index may be useful for selecting patients with AECOPD that are suitable for NIV weaning.

Non-invasive Positive Pressure Ventilation for Acute Cardiogenic Pulmonary Edema and Chronic Obstructive Pulmonary Disease in Prehospital and Emergency Settings

Non-invasive ventilation is an important intervention in treating acute respiratory failure caused by acute cardiogenic pulmonary edema (ACPE) and acute exacerbations of chronic obstructive pulmonary disease (COPD). Although there are studies that give evidence on the efficacy and safety of non-invasive ventilation over standard medical care for COPD and cardiogenic pulmonary edema, less are known about the form of non-invasive ventilation, continuous positive airway pressure (CPAP), or bilevel positive airway pressure (BiPAP) as an effective intervention for respiratory failure and its efficacy and safety in prehospital settings. We conducted a systematic review by using PubMed and Google Scholar as databases for collecting studies related to the effectiveness of CPAP and BiPAP for cardiogenic pulmonary edema and COPD; the major outcome studied was reducing rates of endotracheal intubation secondary and tertiary outcomes included mortality reduction and shortening length of hospital stay. The study follows the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) checklist 2009. Sixteen studies were identified, including systematic reviews, randomized control trials, and observational studies. Studies published on or after 2010 in a population greater than 40 years old suffering from acute COPD and cardiogenic pulmonary edema were taken for review. Studies that described other respiratory diseases treated with non-invasive ventilation were excluded. Quality appraisal was done using the Cochrane risk bias tool for randomized control trials, Amstar-2 for systematic reviews, and New Castle Ottawa Tool for observational studies. Five studies compared the effectiveness of CPAP and BiPAP with standard medical care in prehospital and emergency settings. Six studies described prehospital intervention. Both forms of non-invasive ventilation were equally significant and effective. Prehospital use had tremendously reduced intubation rates, with not much variability noticed for mortality and hospital stay. Non-invasive ventilation is an effective measure for respiratory failure secondary to COPD and ACPE. Early out of hospital utilization of CPAP and BiPAP reduces the rate of invasive ventilation and reduces complications due to endotracheal intubation. Endotracheal intubation is associated with a considerable incidence of complications like failed intubation, hypotension, or circulatory arrest, even if the emergency physician is well trained, making these forms of non-invasive ventilation safe and effective interventions in the prehospital settings.

Video-assisted thoracoscopic surgery for primary lung cancer resections in patients with moderate to severe chronic obstructive pulmonary diseases

Background

Lung cancer patients with chronic obstructive pulmonary disease (COPD) are considered a high-risk population to receive radical surgical treatment due to the high incidence of cardiopulmonary complications. The aim of this study was to evaluate the clinical factors associated with postoperative complications in primary lung cancer patients with moderate to extremely severe grades of COPD.

Methods

From December 2015 to June 2020, 138 patients with moderate to extremely severe COPD who underwent video-assisted thoracoscopic surgery (VATS) lung cancer resection (lobectomy or sublobar resection) were retrospectively reviewed. Patients' postoperative complications were collected from clinical records. Clinical factors (such as COPD severity or surgical approaches, etc.) were evaluated to investigate the association with postoperative complications.

Results

Of the 138 patients included in the study, the mean age was 67 (63-74) years, the mean preoperative forced expiratory volume in one second (FEV1) was 1.33±0.39 L, the mean FEV1% was 51.23% (41.43-60.00%). 33% patients (46/138) had postoperative complications, and no mortality occurred. Univariate analysis revealed that incidence of overall complications (OCs) and respiratory complications (RCs) was markedly higher in extremely severe COPD patients compared to moderate (OCs, P=0.033; RCs, P=0.050) and severe (OCs, P=0.015; RCs, P=0.008) COPD patients, respectively. Multivariate analysis showed that COPD grade was an independent risk factor of RCs (P=0.024). Furthermore, the grades of COPD (moderate, P=0.029; severe, P=0.028; extremely severe, P=0.019) and the surgical procedure (lobectomy or sublobar resection, P=0.043) were independent risk factors for atelectasis, which was the most common postoperative complication.

Conclusions

The aggravation of COPD was accompanied by an increase in the incidence of respiratory system complications postoperatively, especially atelectasis. For patients with moderate to extremely severe grades of COPD, careful perioperative evaluation should be performed to identify the indicators that influence the surgical choice between lobectomy and sublobar resection.

Analysis of the clinical effect of noninvasive mechanical ventilation in AIDS patients complicated with pneumonia

OBJECTIVE

To explore the clinical application effect of noninvasive mechanical ventilation for patients with acquired immune deficiency syndrome (AIDS) complicated with pneumonia.

METHODS

A prospective study was conducted on 86 patients with AIDS complicated with pneumocystis pneumonia. The patients were randomly divided into a control group and an experimental group, both of which were treated with conventional drugs. The control group was supplemented with oxygen via a mask, and the experimental group was additionally treated with noninvasive ventilator ventilation. The changes of arterial oxygen partial pressure, oxygenation index, respiratory frequency, pulse rate, serum albumin and other indicators between the two groups before and after treatment were observed. The patient's hospitalization time, overall improvement and mortality rate were compared.

RESULTS

Compared with those before treatment, the arterial oxygen partial pressure, oxygenation index, respiratory frequency, and pulse rate of the two groups of patients were significantly improved after treatment (P<0.05). The improvement of the experimental group after treatment was more significant than that of the control group, and the difference was statistically significant (P<0.001). After treatment, the proportion of recovery rate of serum albumin in the experimental group was 81.40%, which was significantly higher than that in the control group (53.49%), and the difference was statistically significant (P<0.05). Compared with the control group, hospitalization time, treatment improvement and mortality rate in the experimental group had significant advantages and statistical significance (P<0.05).

CONCLUSION

For AIDS patients complicated with pneumonia, noninvasive mechanical ventilation had obvious treatment effects, which could significantly improve respiratory function, reduce mortality rate, and increase recovery rate. It can be considered as a therapeutic method to be included in routine treatment protocols.

Prehospital continuous positive airway pressure for acute respiratory failure: the ACUTE feasibility RCT

BACKGROUND

Acute respiratory failure is a life-threatening emergency. Standard prehospital management involves controlled oxygen therapy. Continuous positive airway pressure is a potentially beneficial alternative treatment; however, it is uncertain whether or not this treatment could improve outcomes in NHS ambulance services.

OBJECTIVES

To assess the feasibility of a large-scale pragmatic trial and to update an existing economic model to determine cost-effectiveness and the value of further research.

DESIGN

(1) An open-label, individual patient randomised controlled external pilot trial. (2) Cost-effectiveness and value-of-information analyses, updating an existing economic model. (3) Ancillary substudies, comprising an acute respiratory failure incidence study, an acute respiratory failure diagnostic agreement study, clinicians perceptions of a continuous positive airway pressure mixed-methods study and an investigation of allocation concealment.

SETTING

Four West Midlands Ambulance Service hubs, recruiting between August 2017 and July 2018.

PARTICIPANTS

Adults with respiratory distress and peripheral oxygen saturations below the British Thoracic Society's target levels were included. Patients with limited potential to benefit from, or with contraindications to, continuous positive airway pressure were excluded.

INTERVENTIONS

Prehospital continuous positive airway pressure (O-Two system, O-Two Medical Technologies Inc., Brampton, ON, Canada) was compared with standard oxygen therapy, titrated to the British Thoracic Society's peripheral oxygen saturation targets. Interventions were provided in identical sealed boxes.

MAIN OUTCOME MEASURES

Feasibility objectives estimated the incidence of eligible patients, the proportion recruited and allocated to treatment appropriately, adherence to allocated treatment, and retention and data completeness. The primary clinical end point was 30-day mortality.

RESULTS

Seventy-seven patients were enrolled (target 120 patients), including seven patients with a diagnosis for which continuous positive airway pressure could be ineffective or harmful. Continuous positive airway pressure was fully delivered to 74% of participants (target 75%). There were no major protocol violations/non-compliances. Full data were available for all key outcomes (target ≥ 90%). Thirty-day mortality was 27.3%. Of the 21 deceased participants, 14 (68%) either did not have a respiratory condition or had ceiling-of-treatment decision implemented that excluded hospital non-invasive ventilation and critical care. The base-case economic evaluation indicated that standard oxygen therapy was probably cost-effective (incremental cost-effectiveness ratio £5685 per quality-adjusted life-year), but there was considerable uncertainty (population expected value of perfect information of £16.5M). Expected value of partial perfect information analyses indicated that effectiveness of prehospital continuous positive airway pressure was the only important variable. The incidence rate of acute respiratory failure was 17.4 (95% confidence interval 16.3 to 18.5) per 100,000 persons per year. There was moderate agreement between the primary prehospital and final hospital diagnoses (Gwet's AC1 coefficient 0.56, 95% confidence interval 0.43 to 0.69). Lack of hospital awareness of the Ambulance continuous positive airway pressure (CPAP): Use, Treatment Effect and economics (ACUTE) trial, limited time to complete trial training and a desire to provide continuous positive airway pressure treatment were highlighted as key challenges by participating clinicians.

LIMITATIONS

During week 10 of recruitment, the continuous positive airway pressure arm equipment boxes developed a 'rattle'. After repackaging and redistribution, no further concerns were noted. A total of 41.4% of ambulance service clinicians not participating in the ACUTE trial indicated a difference between the control and the intervention arm trial boxes (115/278); of these clinician 70.4% correctly identified box contents.

CONCLUSIONS

Recruitment rate was below target and feasibility was not demonstrated. The economic evaluation results suggested that a definitive trial could represent value for money. However, limited compliance with continuous positive airway pressure and difficulty in identifying patients who could benefit from continuous positive airway pressure indicate that prehospital continuous positive airway pressure is unlikely to materially reduce mortality.

FUTURE WORK

A definitive clinical effectiveness trial of continuous positive airway pressure in the NHS is not recommended.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN12048261.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 7. See the NIHR Journals Library website for further project information.

The application of non-invasive and invasive mechanical ventilation in the first episode of acute respiratory failure

Acute respiratory failure (RF) is a life-threatening syndrome. This study investigated the application of two major clinical strategies, non-invasive mechanical ventilation (NIV) and invasive mechanical ventilation (IMV), in the first episode of acute RF. Data from the longitudinal health insurance database, which included 1,000,000 insured citizens, were used. The NIV group consisted of 1201 patients and the IMV group consisted of 16,072 patients. Chi-square test and t test were applied to determine the differences in categorical and continuous variables. Further analysis was performed by using univariate and multivariable logistic regression and Poisson regression. There was a significant increase of 733% in the number of NIV users from 2000 to 2012. NIV use was frequently observed in old-age persons (aOR 3.99, 95% CI 3.06-5.21 for those aged ≥ 80 years), women (aOR 1.33, 95% CI 1.18-1.50), patients admitted to a high-level hospital (aOR 1.95, 95% CI 1.63-2.34 for those admitted to a medical center), and patients with a higher Charlson comorbidity index (CCI, aOR 1.38-1.66 for those CCI ≥ 2). In addition, patients with chronic pulmonary disease, cancer, and congestive heart failure were predominant in NIV users and were significantly associated with NIV use. Overall, the use of NIV has markedly increased over the past few years. Persons of advanced age, women, patients admitted to a high-level hospital, and patients with multiple comorbidities were associated with more frequent NIV use. Chronic pulmonary disease, cancer, and congestive heart failure were most important comorbidities for NIV use.

Predictive Factors for Failure of Noninvasive Ventilation in Adult Intensive Care Unit: A Retrospective Clinical Study

Background

Noninvasive ventilation (NIV) has been reported to be beneficial for patients with acute respiratory failure in intensive care unit (ICU); however, factors that influence the clinical outcome of NIV were unclarified. We aim to determine the factors that predict the failure of NIV in critically ill patients with acute respiratory failure (ARF). Setting. Adult mixed ICU in a medical university affiliated hospital. Patients and Methods. A retrospective clinical study using data from critical adult patients with initial NIV admitted to ICU in the period August 2016 to November 2017. Failure of NIV was regarded as patients needing invasive ventilation. Logistic regression was employed to determine the risk factor(s) for NIV, and a predictive model for NIV outcome was set up using risk factors.

Results

Of 101 included patients, 50 were unsuccessful. Although more than 20 variables were associated with NIV failure, multivariate logistic regression demonstrated that only ideal body weight (IBW) (OR 1.110 (95%1.027-1.201), P=0.009), the maximal heart rate during NIV period (HR-MAX) (OR 1.024 (1.004-1.046), P=0.021), the minimal respiratory rate during NIV period (RR-MIN) (OR 1.198(1.051-1.365), P=0.007), and the highest body temperature during NIV period (T-MAX) (OR 1.838(1.038-3.252), P=0.037) were independent risk factors for NIV failure. We set up a predictive model based on these independent risk factors, whose area under the receiver operating characteristic curve (AUROC) was 0.783 (95% CI: 0.676-0.899, P < 0.001), and the sensitivity and specificity of model were 68.75% and 71.43%, respectively, with the optimal cut-off value of 0.4863.

Conclusion

IBW, HR-MAX, RR-MIN, and T-MAX were associated with NIV failure in patients with ARF. A predictive model based on the risk factors could help to discriminate patients who are vulnerable to NIV failure.

Daytime noninvasive ventilatory support for patients with ventilatory pump failure: a narrative review

Over the past three decades, the use of noninvasive ventilation or "NIV" to assuage symptoms of hypoventilation for patients with early onset or mild ventilatory pump failure has been extended to up to the use of continuous noninvasive ventilatory support (CNVS) at full ventilatory support settings as a definitive alternative to tracheostomy mechanical ventilation. NVS, along with mechanical insufflation-exsufflation, now provides a noninvasive option for the management of both chronic and acute respiratory failure for these patients. The most common diagnoses for which these methods are useful include chest wall deformities, neuromuscular diseases, morbid obesity, high level spinal cord injury and idiopathic, primary or secondary disorders of the ventilatory control. Thus, NVS is being used in diverse settings: critical care units, medical wards, at home, and in extended care. The aim of this review is to examine the techniques used for daytime support.

Clinical efficacy of high-flow nasal humidified oxygen therapy in patients with hypoxemia

To evaluate the effectiveness of high-flow nasal humidified oxygen (HFNHO) therapy in patients with mild hypoxemia after extubation. This study included 316 patients with mild hypoxemia after extubation from May 2016 to May 2018 from two intensive care units in China. Compare the effects of the Venturi Mask and High-Flow Nasal Humidified Oxygen (HFNHO) therapy on Heart Rate (HR), Respiratory Rate (RR), Oxygen Saturation (SpO₂), Oxygen Partial Pressure (PO₂), Partial Pressure Of Carbon Dioxide (PCO₂), Oxygenation Index (PO₂/FiO₂) after extubation, the use of noninvasive mechanical ventilation and tracheal intubation after treatment failure were observed and recorded. Patients have both lower HR and RR than those who received mask treatment (75.4±18.5 vs. 83.0±20.4, p = 0.0004; 18±6.5 vs. 23.6±10.3, p<0.001, respectively). There was significant difference between those who had HFNHO and mask administration’s SpO₂ and PO₂ (94.1±6.4 vs. 87.5±1.5, p<0.001; 88.16±2.9 vs. 77.3±2.3, p<0.001, respectively). For the HFNHO group, patients had lower PCO₂ with the mask group. (41.3±0.99 vs 42.2±1.2, p<0.001). On the other hand, the levels of PO₂/FiO₂ was significantly higher in the HFNHO Group, (181.0±8.3 vs. 157.2±4.9, p<0.05). We concluded HFNHO therapy could significantly relieve the symptoms of dyspnea, improve oxygenation, reduce the use of noninvasive mechanical ventilation and reduce the rate of secondary tracheal intubation in patients with mild hypoxemia after extubation.

New modalities for non-invasive positive pressure ventilation: A review article

Efficiency of non-invasive positive pressure ventilation in the treatment of respiratory failure has been shown in many published studies. In this review article, we introduced new modalities of non-invasive ventilation (NIV), clinical settings in which NIV can be used and a practical summary of the latest official guidelines published by the European Respiratory Clinical Practice. Clinical trials and review articles in four databases up to 25 February 2018 about new modalities of non-invasive positive pressure ventilation were reviewed. Commonly used modalities for treatment of respiratory failure include: CPAP (continuous positive airway pressure) and BiPAP (bilevel positive airway pressure) or NIPSV (noninvasive pressure support ventilation). The limitations of the BiPAP method are the trigger and cycle asynchrony, inadequate volume delivery and increased respiratory rate. Newer methods, such as adaptive servo-ventilation, have been developed to treat central and complex sleep apnea and the NAVA (neutrally adjusted ventilatory assist) to improve the trigger and cycle asynchrony. In the proportional assist ventilation, unlike the pressure support ventilation, with increased patient effort (flow) the tidal volume increases and it prevents the increase in the respiratory rate and respiratory distress. High-flow nasal cannula is a non-invasive technique that does not provide respiratory support, but provides a mixture of oxygen to the patient. The use of non-invasive pursed-lip breathing ventilation in chronic obstructive pulmonary disease (COPD) patients reduces dyspnea (decreases respiratory rate) and increases blood oxygen saturation. New modalities of NIV improve patient comfort and patient-ventilator interactions, and are recommended in patients with respiratory failure.

Nasal high-frequency oscillatory ventilation (nHFOV) versus nasal continuous positive airway pressure (NCPAP) as an initial therapy for respiratory distress syndrome (RDS) in preterm and near-term infants

BACKGROUND

Currently, various forms of non-invasive respiratory support have been used in the management of respiratory distress syndrome (RDS) in preterm neonates. However, nasal high-frequency oscillatory ventilation (nHFOV) has not yet been applied commonly as an initial treatment.

OBJECTIVES

This study was designed to investigate the efficacy and safety of nHFOV compared with nasal continuous positive airway pressure (NCPAP) in preterm and near-term infants with RDS.

METHODS

In a randomised clinical trial, a total of 68 neonates (gestational age (GA) between 30 and 36 weeks and 6 days) with a clinical diagnosis of RDS were randomly assigned to either the NCPAP (n=34) or the nHFOV (n=34) group. The primary outcome was the duration of non-invasive respiratory support (duration of using NCPAP or nHFOV).

RESULT

The median (IQR) duration of non-invasive respiratory support, was significantly shorter in the nHFOV group than that in the NCPAP group (20 (15-25.3) versus 26.5 (15-37.4) hours, respectively; p=0.02). The need for a ventilator occurred in 4 out of 34 (11.8%) neonates in the NCPAP group and in none of the neonates in the nHFOV group (p=0.03). In addition, intraventricular haemorrhage (IVH) occurred in nine cases (6.9%) in the NCPAP group and two cases (3.3%) in the nHFOV group, which showed a significant difference (p=0.04). The incidence of pneumothorax, chronic lung disease, pulmonary haemorrhage and necrotising enterocolitis was similar between the two groups.

CONCLUSION

This study showed that nHFOV significantly reduced the duration of non-invasive respiratory support and decreased the need for intubation compared with NCPAP in infants with RDS. Furthermore, nHFOV seems to reduce the incidence of IVH without increasing other complications.

TRIAL REGISTRATION NUMBER

IRCT2017062734782N1.

The ACUTE (Ambulance CPAP: Use, Treatment effect and economics) feasibility study: a pilot randomised controlled trial of prehospital CPAP for acute respiratory failure

Background

Acute respiratory failure (ARF) is a common and life-threatening medical emergency. Standard prehospital management involves controlled oxygen therapy and disease-specific ancillary treatments. Continuous positive airway pressure (CPAP) is a potentially beneficial alternative treatment that could be delivered by emergency medical services. However, it is uncertain whether this treatment could work effectively in United Kingdom National Health Service (NHS) ambulance services and if it represents value for money.

Methods

An individual patient randomised controlled external pilot trial will be conducted comparing prehospital CPAP to standard oxygen therapy for ARF. Adults presenting to ambulance service clinicians will be eligible if they have respiratory distress with peripheral oxygen saturation below British Thoracic Society (BTS) target levels, despite titrated supplemental oxygen. Enrolled patients will be allocated (1:1 simple randomisation) to prehospital CPAP (O_two system) or standard oxygen therapy using identical sealed boxes. Feasibility outcomes will include incidence of recruited eligible patients, number of erroneously recruited patients and proportion of cases adhering to allocation schedule and treatment, followed up at 30 days and with complete data collection. Effectiveness outcomes will comprise survival at 30 days (definitive trial primary end point), endotracheal intubation, admission to critical care, length of hospital stay, visual analogue scale (VAS) dyspnoea score, EQ-5D-5L and health care resource use at 30 days. The cost-effectiveness of CPAP, and of conducting a definitive trial, will be evaluated by updating an existing economic model. The trial aims to recruit 120 patients over 12 months from four regional ambulance hubs within the West Midlands Ambulance Service (WMAS). This sample size will allow estimation of feasibility outcomes with a precision of < 5%. Feasibility and effectiveness outcomes will be reported descriptively for the whole trial population, and each trial arm, together with their 95% confidence intervals.

Discussion

This study will determine if it is feasible, acceptable and cost-effective to undertake a full-scale trial comparing CPAP and standard oxygen treatment, delivered by ambulance service clinicians for ARF. This will inform NHS practice and prevent inappropriate prehospital CPAP adoption on the basis of limited evidence and at a potentially substantial cost.

Trial registration

ISRCTN12048261. Registered on 30 August 2017. http://www.isrctn.com/ISRCTN12048261

Effects of Modes, Obesity, and Body Position on Non-invasive Positive Pressure Ventilation Success in the Intensive Care Unit: A Randomized Controlled Study

OBJECTIVES

Different outcomes and success rates of non-invasive positive pressure ventilation (NPPV) in patients with acute hypercapnic respiratory failure (AHRF) still pose a significant problem in intensive care units. Previous studies investigating different modes, body positioning, and obesity-associated hypoventilation in patients with chronic respiratory failure showed that these factors may affect ventilator mechanics to achieve a better minute ventilation. This study tried to compare pressure support (BiPAP-S) and average volume targeted pressure support (AVAPS-S) modes in patients with acute or acute-on-chronic hypercapnic respiratory failure. In addition, short-term effects of body position and obesity within both modes were analyzed.

MATERIAL and METHODS

We conducted a randomized controlled study in a 7-bed intensive care unit. The course of blood gas analysis and differences in ventilation variables were compared between BiPAP-S (n=33) and AVAPS-S (n=29), and between semi-recumbent and lateral positions in both modes.

RESULTS

No difference was found in the length of hospital stay and the course of PaCO2, pH, and HCO3 levels between the modes. There was a mean reduction of 5.7±4.1 mmHg in the PaCO2 levels in the AVAPS-S mode, and 2.7±2.3 mmHg in the BiPAP-S mode per session (p<0.05). Obesity didn't have any effect on the course of PaCO2 in both the modes. Body positioning had no notable effect in both modes.

CONCLUSION

Although the decrease in the PaCO2 levels in the AVAPS-S mode per session was remarkably high, the course was similar in both modes. Furthermore, obesity and body positioning had no prominent effect on the PaCO2 response and ventilator mechanics. Post hoc power analysis showed that the sample size was not adequate to detect a significant difference between the modes.

IL-8 predicts early mortality in patients with acute hypercapnic respiratory failure treated with noninvasive positive pressure ventilation

Background

Patients with Acute Hypercapnic Respiratory Failure (AHRF) who are unresponsive to appropriate medical treatment, are often treated with Noninvasive Positive Pressure Ventilation (NPPV). Clinical predictors of the outcome of this treatment are scarce. Therefore, we evaluated the role of the biomarkers IL-8 and GDF-15 in predicting 28-day mortality in patients with AHRF who receive treatment with NPPV.

Methods

The study population were 46 patients treated with NPPV for AHRF. Clinical and background data was registered and blood samples taken for analysis of inflammatory biomarkers. IL-8 and GDF-15 were selected for analysis, and related to risk of 28-day mortality (primary endpoint) using Cox proportional hazard models adjusted for gender, age and various clinical parameters.

Results

Of the 46 patients, there were 3 subgroup in regards to primary diagnosis: Acute Exacerbation of COPD (AECOPD, n = 34), Acute Heart Failure (AHF, n = 8) and Acute Exacerbation in Obesity Hypoventilation Syndrome (AEOHS, n = 4). There was significant difference in the basic characteristic of the subgroups, but not in the clinical parameters that were used in treatment decisions. 13 patients died within 28 days of admission (28%). The Hazard Ratio for 28-days mortality per 1-SD increment of IL-8 was 3.88 (95% CI 1.86–8.06, p < 0.001). When IL-8 values were divided into tertiles, the highest tertile had a significant association with 28 days mortality, HR 10.02 (95% CI 1.24–80.77, p for trend 0.03), compared with the lowest tertile. This correlation was maintained when the largest subgroup with AECOPD was analyzed. GDF-15 was correlated in the same way, but when put into the same model as IL-8, the significance disappeared.

Conclusion

IL-8 is a target to explore further as a predictor of 28 days mortality, in patients with AHRF treated with NPPV.

Use of noninvasive ventilation in immunocompromised patients with acute respiratory failure: a systematic review and meta-analysis

Background

Acute respiratory failure (ARF) remains a common hazardous complication in immunocompromised patients and is associated with increased mortality rates when endotracheal intubation is needed. We aimed to evaluate the effect of early noninvasive ventilation (NIV) compared with oxygen therapy alone in this patient population.

Methods

We searched for relevant studies in MEDLINE, EMBASE, and the Cochrane database up to 25 July 2016. Randomized controlled trials (RCTs) were included if they reported data on any of the predefined outcomes in immunocompromised patients managed with NIV or oxygen therapy alone. Results were expressed as risk ratio (RR) and mean difference (MD) with accompanying 95% confidence interval (CI).

Results

Five RCTs with 592 patients were included. Early NIV significantly reduced short-term mortality (RR 0.62, 95% CI 0.40 to 0.97, p = 0.04) and intubation rate (RR 0.52, 95% CI 0.32 to 0.85, p = 0.01) when compared with oxygen therapy alone, with significant heterogeneity in these two outcomes between the pooled studies. In addition, early NIV was associated with a shorter length of ICU stay (MD −1.71 days, 95% CI −2.98 to 1.44, p = 0.008) but not long-term mortality (RR 0.92, 95% CI 0.74 to 1.15, p = 0.46).

Conclusions

The limited evidence indicates that early use of NIV could reduce short-term mortality in selected immunocompromised patients with ARF. Further studies are needed to identify in which selected patients NIV could be more beneficial, before wider application of this ventilator strategy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1586-9) contains supplementary material, which is available to authorized users.

Helmet CPAP versus Oxygen Therapy in Hypoxemic Acute Respiratory Failure: A Meta-Analysis of Randomized Controlled Trials

PURPOSE

The efficacy of helmet continuous positive airway pressure (CPAP) in hypoxemic acute respiratory failure (hARF) remains unclear. The aim of this meta-analysis was to critically review studies that investigated the effect of helmet CPAP on gas exchange, mortality, and intubation rate in comparison with standard oxygen therapy.

MATERIALS AND METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) by searching the PubMed, Embase, Cochrane library, OVID, and CBM databases, and the bibliographies of the retrieved articles. Studies that enrolled adults with hARF who were treated with helmet CPAP and measured at least one of the following parameters were included: gas exchange, intubation rate, in-hospital mortality rate.

RESULTS

Four studies with 377 subjects met the inclusion criteria and were analyzed. Compared to the standard oxygen therapy, helmet CPAP significantly increased the PaO₂/FiO₂ [weighted mean difference (WMD)=73.40, 95% confidence interval (95% CI): 43.92 to 102.87, p<0.00001], and decreased the arterial carbon dioxide levels (WMD=-1.92, 95% CI: -3.21 to -0.63, p=0.003), intubation rate [relative risk (RR)=0.21, 95% CI: 0.11 to 0.40, p<0.00001], and in-hospital mortality rate (RR=0.22, 95% CI: 0.09 to 0.50, p=0.0004).

CONCLUSION

The results of this meta-analysis suggest that helmet CPAP improves oxygenation and reduces mortality and intubation rates in hARF. However, the significant clinical and statistical heterogeneity of the literature implies that large RCTs are needed to determine the role of helmet CPAP in different hypoxemic ARF populations.

Pathophysiological Basis of Acute Respiratory Failure on Non-Invasive Mechanical Ventilation

Noninvasive mechanical ventilation (NIMV) was created for patients who needed noninvasive ventilator support, this procedure decreases the complications associated with the use of endotracheal intubation (ETT). The application of NIMV has acquired major relevance in the last few years in the management of acute respiratory failure (ARF), in patients with hypoxemic and hypercapnic failure. The main advantage of NIMV as compared to invasive mechanical ventilation (IMV) is that it can be used earlier outside intensive care units (ICUs). The evidence strongly supports its use in patients with COPD exacerbation, support in weaning process in chronic obstructive pulmonary disease (COPD) patients, patients with acute cardiogenic pulmonary edema (ACPE), and Immunosuppressed patients. On the other hand, there is poor evidence that supports the use of NIMV in other pathologies such as pneumonia, acute respiratory distress syndrome (ARDS), and during procedures as bronchoscopy, where its use is still controversial because the results of these studies are inconclusive against the decrease in the rate of intubation or mortality.

Humidification on Ventilated Patients: Heated Humidifications or Heat and Moisture Exchangers?

The normal physiology of conditioning of inspired gases is altered when the patient requires an artificial airway access and an invasive mechanical ventilation (IMV). The endotracheal tube (ETT) removes the natural mechanisms of filtration, humidification and warming of inspired air. Despite the noninvasive ventilation (NIMV) in the upper airways, humidification of inspired gas may not be optimal mainly due to the high flow that is being created by the leakage compensation, among other aspects. Any moisture and heating deficit is compensated by the large airways of the tracheobronchial tree, these are poorly suited for this task, which alters mucociliary function, quality of secretions, and homeostasis gas exchange system. To avoid the occurrence of these events, external devices that provide humidification, heating and filtration have been developed, with different degrees of evidence that support their use.

Predictors of non-invasive ventilation failure in severe respiratory failure due to community acquired pneumonia

BACKGROUND

Non-invasive ventilation (NIV) has been used for acute respiratory failure to avoid endotracheal intubation and intensive care admission. Few studies have assessed the usefulness of NIV in patients with severe community acquired pneumonia (CAP). The use of NIV in severe CAP is controversial because there is a greater variability in success compared to other pulmonary conditions.

MATERIALS AND METHODS

We retrospectively followed 130 patients with CAP and severe acute respiratory failure (PaO2/FiO2 < 250) admitted to a Respiratory Monitoring Unit (RMU) and underwent NIV. We assessed predictors of NIV failure and hospital mortality using univariate and multivariate analyses.

RESULTS

NIV failed in 26 patients (20.0%). Higher chest X-ray score at admission, higher heart rate after 1 hour of NIV, and a higher alveolar-arteriolar gradient (A-aDO2) after 24 hours of NIV each independently predicted NIV failure. Higher chest X ray score, higher LDH at admission, higher heart rate after 24 hours of NIV and higher A-aDO2 after 24 hours of NIV were directly related to hospital mortality.

CONCLUSION

NIV treatment had high rate of success. Successful treatment is related to less lung involvement and to early good response to NIV and continuous improvement in clinical response.