Non-invasive positive pressure ventilation (CPAP or bilevel NPPV) for cardiogenic pulmonary oedema

Relation between partial arterial carbon dioxide pressure and pH value and optic nerve sheath diameter: a prospective self-controlled non-randomized trial study

OBJECTIVE

This study aims to determine if there is a correlation between differences in optic nerve sheath diameter (ONSD) and changes in PaCO2 and pH values that were measured in the arterial blood gas (ABG) before and after treatment in COPD patients with acute hypercarbic respiratory failure (AHRF).

MATERIALS AND METHODS

This study serves as a prospective self-controlled non-randomized trial study conducted in the emergency clinic of a tertiary hospital. Forty-four patients with COPD, who were found to have acidosis and hypercarbia in ABG and had an indication for non-invasive mechanic ventilation (NIMV), were analyzed prospectively. Demographic information, vital findings, initial ABG values, the ONSD measurement (before the NIMV treatment), consciousness state, and the ABG results obtained in the second hour of the monitoring and the ONSD measurement (after the NIMV treatment) were recorded.

RESULTS

In this study, 13 (29.5%) of the patients were female and 31 (70.5%) were male. The age distribution was evaluated as 68.3 ± 9.2 years; the minimum age was 54 and the maximum was 91. A high level of positively significant correlation was found between the mean ONSD and PaCO2 (p < 0.0001). There is a high fit (0.72) between the mean ONSD and PaCO2. A moderate level of negatively significant correlation was found between the mean ONSD and the pH (p < 0.0001). However, there is an insignificant low fit (0.32) between the mean ONSD and the pH.

CONCLUSION

The ONSD changed significantly and in a highly correlated manner to acute changes in PaCO2 levels.

Factors and Outcomes Associated with Failed Noninvasive Positive Pressure Ventilation in Patients with Acute Respiratory Failure

Background

The decision guild for non-invasive positive pressure ventilation (NPPV) application in acute respiratory failure (ARF) patients still needs to work out.

Methods

Adult patients with acute hypoxemic or hypercapnic respiratory failure were recruited and treated with NPPV or primary invasive mechanical ventilation (IMV). Patients’ characteristic and clinical outcomes were recorded. Logistic regression models were used to estimate the adjusted odds ratio (aOR) and 95% confidence intervals for baseline characteristics and clinical outcomes. Subgroup analyses by reason behind successful NPPV were conducted to ascertain if any difference could influence the outcome.

Results

A total of 4525 ARF patients were recruited in our facility between year 2015 and 2017. After exclusion, 844 IMV patients, 66 patients with failed NPPV, and 74 patients with successful NPPV were enrolled. Statistical analysis showed APACHE II score (aOR = 0.93), time between admission and start NPPV (aOR = 0.92), and P/F ratio (aOR = 1.04) were associated with successful NPPV. When comparing with IMV patients, failed NPPV patients displayed a significantly lower APACHE II score, higher Glasgow Coma Scale, longer length of stay in hospital, longer duration of invasive ventilation, RCW/Home ventilator, and some comorbidities.

Conclusion

APACHE II score, time between admission and start NPPV, and PaO2 can be predictors for successful NPPV. The decision of NPPV application is critical as ARF patients with failed NPPV have various worse outcomes than patients receiving primary IMV.

Parallel-group, randomised, controlled, non-inferiority trial of high-flow nasal cannula versus non-invasive ventilation for emergency patients with acute cardiogenic pulmonary oedema: study protocol

INTRODUCTION

High-flow nasal cannula (HFNC) is an innovative oxygen-delivering technique, which has been shown to effectively decrease the intubation risk in patients with hypoxaemic respiratory failure of various aetiologies compared with conventional oxygen therapy. Also, it has proved to be non-inferior to non-invasive positive pressure ventilation (NIPPV) in patients with hypoxaemic respiratory failure primarily due to pneumonia. Evidence on its benefits compared with NIPPV, which is the standard of care for patients with acute cardiogenic pulmonary oedema (ACPE) with hypoxaemic respiratory distress, is limited. Therefore, we planned this study to investigate the effects of HFNC compared with NIPPV for emergency patients with ACPE.

METHODS AND ANALYSIS

In this single-centred, non-blinded, parallel-group, randomised, controlled, non-inferiority trial, we will randomly allocate 240 patients visiting the emergency department with ACPE in a 1:1 ratio to receive either HFNC or NIPPV for at least 4 hours using computer-generated mixed-block randomisation concealed by sealed opaque envelopes. The primary outcome is the intubation rate in 72 hours after randomisation. The main secondary outcomes are intolerance rate, mortality rate and treatment failure rate (a composite of intolerance, intubation and mortality). The outcome assessors and data analysts will be blinded to the intervention. These categorical outcomes will be analysed by calculating the risk ratio. Interim analyses evaluating the primary outcome will be performed after half of the expected sample size are recruited.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Siriraj Institutional Review Board (study ID: Si 271/2021). It has been granted the Siriraj Research and Development Fund. All participants or their authorised third parties will provide written informed consent prior to trial inclusion. The study results will be published in a peer-reviewed international journal and presented at national and international scientific conferences.

TRIAL REGISTRATION NUMBER

TCTR20210413001.

Comparison of Local and Systemic Inflammation During Invasive Versus Noninvasive Ventilation in Rats

The impact of noninvasive ventilation (NIV) on local and systemic inflammation is poorly characterized, particularly when compared with invasive mechanical ventilation (IMV). We sought to quantify the local and systemic inflammatory response of these 2 respiratory treatments in rats with lipopolysaccharide (LPS)-induced lung injury (LPS-injured) and healthy rats. Animals were subjected to 4 h of NIV or IMV treatments at noninjurious settings, or 4 h of control treatment in which healthy or LPS-injured animals remained spontaneously breathing under isoflurane anesthesia with no respiratory support. Cytokines were then quantified in the serum and lung tissue by multiplex enzyme-linked immunosorbent assay. Contrary to our hypothesis, there were no significant differences in cytokine levels in serum or lung when comparing the NIV- and IMV-treated groups; this was true in both LPS-injured and healthy rats. However, within the LPS-injured group, pulmonary levels of interleukin (IL)-1α, IL-6, and tumor necrosis factor α were significantly lower in the NIV-treated group than in control but not in the IMV-treated group compared with control. We conclude that NIV, unlike IMV, could attenuate local inflammation.

The Association Between Early Administration of Noninvasive Ventilation and Short-Term Outcome for Acute Heart Failure

Background Acute decompensated heart failure (ADHF) is a life-threatening disease that requires emergent intervention. Although noninvasive positive pressure ventilation (NPPV) is crucial for treating ADHF, the earliest time point for administering NPPV remains unknown. In this study, we hypothesized that early NPPV administration for patients with acute heart failure in the emergency department (ED) would lead to a better outcome. Methodology This is a single-center retrospective cohort study at an ED of a community hospital in Japan. The data were collected from consecutive patients who were administered NPPV for ADHF in the ED from April 2016 to September 2018. The primary exposure was the timing of NPPV administration (within 30 minutes versus over 30 minutes after arrival). The primary outcome was 30-day mortality. Results A total of 115 patients were included in this study. Overall, the median age was 78 (interquartile range [IQR] = 70-84 years), and 63 (54.9%) patients were male. The median time from the arrival at the ED to NPPV administration for the patients was 14 minutes (IQR = 8-30 minutes). Overall, 72% (83/115) of the patients were categorized as early administration group (<30 minutes). The total 30-day mortality was 7.0% (8/115), and the total tracheal intubation rate was 11% (13/115). Early NPPV administration for patients with ADHF was associated with lower 30-day mortality (3.6% vs. 16%; p = 0.04) and shorter length of oxygenation (four days vs. seven days; p < 0.01). Multivariate logistic regression test showed that 30-day mortality was significantly lower in the early treatment group (adjusted odds ratio = 0.19; 95% confidential interval = 0.04-0.90). Conclusions Although further investigation is needed, early NPPV administration for patients with ADHF in the ED was associated with lower 30-day mortality.

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.

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.

Use of continuous positive airway pressure and non-invasive ventilation for respiratory failure in an Australian aeromedical retrieval service: A retrospective case series

OBJECTIVE

The purpose of the present study was to investigate the use of respiratory support via continuous positive airway pressure (CPAP) and non-invasive ventilation (NIV) in a medical retrieval service in Queensland, Australia, with reference to transport considerations and patient safety.

METHODS

In this unblinded retrospective case series over a 13-month period, a clinical database was reviewed for the use of CPAP/NIV. Retrieval metrics as well as clinical data were recorded.

RESULTS

A total of 128 patients were transferred either by rotary (80%) or fixed wing (20%). The median transport time was 65 min. The median total mission time was 3.7 h. Fifty-two percent of patients were female. The median age was 69 years and 93% had a background of cardiorespiratory disease. Sixty-five percent of patients were receiving CPAP/NIV before arrival of the retrieval team. The main diagnoses were respiratory failure (29.7%), acute pulmonary oedema (26.6%) and chronic obstructive pulmonary disease (25.8%). There were no incidences of pneumothorax, intubation in transit, vomiting, desaturation, hypotension, cardiac arrest or death. In two cases NIV was abandoned due to mask intolerance and in one case there was a decrease in Glasgow Coma Scale by 2. In no cases was there a detrimental outcome for the patient.

CONCLUSION

The use of NIV and CPAP appears to have a low-risk profile in aeromedical retrieval even for prolonged periods of time in an adult population.

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.

Prehospital arterial hypercapnia in acute heart failure is associated with admission to acute care units and emergency room length of stay: a retrospective cohort study

BACKGROUND

Acute Heart Failure (AHF) is a common condition that often presents with acute respiratory distress and requires urgent medical evaluation and treatment. Arterial hypercapnia is common in AHF and has been associated with a higher rate of intubation and non-invasive ventilation in the Emergency Room (ER), but its prognostic value has never been studied in the prehospital setting.

METHODS

A retrospective study was performed on the charts of all patients taken care of by a physician-staffed prehospital mobile unit between June 2016 and September 2019 in Geneva. After approval by the ethics committee, charts were screened to identify all adult patients with a diagnosis of AHF in whom a prehospital arterial blood gas (ABG) sample was drawn. The main predictor was prehospital hypercapnia. The primary outcome was the admission rate in an acute care unit (ACU, composite of intensive care and high-dependency units). Secondary outcomes were ER length of stay (LOS), orientation from ER (intensive care unit, high-dependency unit, general ward, discharge home), intubation rate at 24 h, hospital LOS and hospital mortality.

RESULTS

A total of 106 patients with a diagnosis of AHF were analysed. Hypercapnia was found in 61 (58%) patients and vital signs were more severely altered in this group. The overall ACU admission rate was 48%, with a statistically significant difference between hypercapnic and non-hypercapnic patients (59% vs 33%, p = 0.009). ER LOS was shorter in hypercapnic patients (5.4 h vs 8.9 h, p = 0.016).

CONCLUSIONS

There is a significant association between prehospital arterial hypercapnia, acute care unit admission, and ER LOS in AHF patients.

Critically Ill Adults With Coronavirus Disease 2019 in New Orleans and Care With an Evidence-Based Protocol

Background

Characteristics of critically ill adults with coronavirus disease 2019 (COVID-19) in an academic safety net hospital and the effect of evidence-based practices in these patients are unknown.

Research Question

What are the outcomes of critically ill adults with COVID-19 admitted to a network of hospitals in New Orleans, Louisiana, and what is an evidence-based protocol for care associated with improved outcomes?

Study Design and Methods

In this multi-center, retrospective, observational cohort study of ICUs in four hospitals in New Orleans, Louisiana, we collected data on adults admitted to an ICU and tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between March 9, 2020 and April 14, 2020. The exposure of interest was admission to an ICU that implemented an evidence-based protocol for COVID-19 care. The primary outcome was ventilator-free days.

Results

The initial 147 patients admitted to any ICU and tested positive for SARS-CoV-2 constituted the cohort for this study. In the entire network, exposure to an evidence-based protocol was associated with more ventilator-free days (25 days; 0-28) compared with non-protocolized ICUs (0 days; 0-23, P = .005), including in adjusted analyses (P = .02). Twenty patients (37%) admitted to protocolized ICUs died compared with 51 (56%; P = .02) in non-protocolized ICUs. Among 82 patients admitted to the academic safety net hospital’s ICUs, the median number of ventilator-free days was 22 (interquartile range, 0-27) and mortality rate was 39%.

Interpretation

Care of critically ill COVID-19 patients with an evidence-based protocol is associated with increased time alive and free of invasive mechanical ventilation. In-hospital survival occurred in most critically ill adults with COVID-19 admitted to an academic safety net hospital’s ICUs despite a high rate of comorbidities.

Protocolized emergency department observation care improves quality of ischemic stroke care in Haiti

INTRODUCTION

In many low-income countries, Emergency Medicine is underdeveloped and faces many operational challenges including emergency department (ED) overcrowding and prolonged patient length of stays (LOS). In high-resource settings, protocolized ED observation unit (EDOU) care reduces LOS while preserving care quality. EDOUs are untested in low-income countries. We evaluate the effect protocolized EDOU care for ischemic stroke on the quality and efficiency of care in Haiti.

METHODS

We performed a prospective cohort study of protocolized observation care for ischemic stroke at a Haitian academic hospital between January 2014 and September 2015. We compared patients cared for in the EDOU using the ischemic stroke protocol (study group) to eligible patients cared for before protocol implementation (baseline group), as well as to eligible patients treated after protocol introduction but managed without the EDOU protocol (contemporary reference group). We analysed three quality of care measures: aspirin administration, physical therapy consultation, and swallow evaluation. We also analysed ED and hospital LOS as measures of efficiency.

RESULTS

Patients receiving protocolized EDOU care achieved higher care quality compared to the baseline group, with higher rates of aspirin administration (91% v. 17%, p < 0.001), physical therapy consultation (50% v. 9.6%, p < 0.001), and swallow evaluation (36% v. 3.7%, p < 0.001). We observed similar improvements in the study group compared to the contemporary reference group. Most patients (92%) were managed entirely in the ED or EDOU. LOS for non-admitted patients was longer in the study group than the baseline group (28 v. 19 h, p = 0.023).

CONCLUSION

Protocolized EDOU care for patients with ischemic stroke in Haiti improved performance on key quality measures but increased LOS, likely due to more interventions. Future studies should examine the aspects of EDOU care are most effective at promoting higher care quality, and if similar results are achievable in patients with other conditions.

Effect of the COVID-19 Pandemic on Acute Respiratory Care of Hypoxemic Patients With Acute Heart Failure in Japan - A Cross-Sectional Study

Background: The effect of the COVID-19 pandemic on the respiratory management strategy with regard to the use of non-invasive positive pressure ventilation (NPPV) and high-flow nasal cannula (HFNC) in patients with acute heart failure (AHF) in Japan is unclear.

Methods and Results: This cross-sectional study used a self-reported online questionnaire, with responses from 174 institutions across Japan. More than 60% of institutions responded that the treatment of AHF patients requiring respiratory management became fairly or very difficult during the COVID-19 pandemic than earlier, with institutions in alert areas considering such treatment significantly more difficult than those in non-alert areas (P=0.004). Overall, 61.7% and 58.8% of institutions changed their indications for NPPV and HFNC, respectively. Significantly more institutions in the alert area changed their practices for the use of NPPV and HFNC during the COVID-19 pandemic (P=0.004 and P=0.002, respectively). When there was insufficient time or information to determine whether AHF patients may have concomitant COVID-19, institutions in alert areas were significantly more likely to refrain from using NPPV and HFNC than institutions in non-alert areas.

Conclusions: The COVID-19 pandemic has compelled healthcare providers to change the respiratory management of AHF, especially in alert areas.

Helmet CPAP revisited in COVID-19 pneumonia: A case series

Introduction

Noninvasive positive pressure ventilation (NIPPV) plays an important role in the management of respiratory failure. However, since the emergence of the COVID-19 pandemic, utilization of traditional face mask NIPPV has been curtailed in part due to risk of aerosolization of respiratory particles and subsequent health care worker exposure. A randomized clinical trial in 2016 reported that an alternative interface, helmet NIPPV, may be more effective than traditional NIPPV at preventing intubation and improving mortality. The helmet NIPPV interface provides positive airway pressure, while also theoretically minimizing aerosolization, making it a feasible modality in management of respiratory failure in COVID-19 patients.

Case and outcomes

This report describes a single-center experience of a series of three COVID-19 patients with hypoxemic respiratory failure managed with helmet NIPPV. One patient was able to avoid intubation while a second patient was successfully extubated to NIPPV. Ultimately, the third patient was unable to avoid intubation with helmet NIPPV, although the application of the device was late in the progression of the disease.

Discussion

NIPPV is an important modality in the management of respiratory failure and has been shown to reduce the need for immediate endotracheal intubation in select populations. For patients unable to tolerate facemask NIPPV, the helmet provides an alternate interface. In COVID-19 patients, the helmet interface may reduce the risk of virus exposure to health care workers from aerosolization. Based on this experience, we recommend that helmet NIPPV can be considered as a feasible option for the management of patients with COVID-19, whether the goal is to prevent immediate intubation or avoid post-extubation respiratory failure. Randomized studies are needed to definitively validate the use of helmet NIPPV in this population.

Conclusion

Helmet NIPPV is a feasible therapy to manage COVID-19 patients.

Meta-Analysis Comparing Outcomes of Therapies for Patients With Central Sleep Apnea and Heart Failure With Reduced Ejection Fraction

Patients with heart failure with reduced ejection fraction and predominant central sleep apnea pose treatment challenges. A system review and meta-analysis of randomized controlled trials (RCTs) were undertaken. Electronic searches of digital repositories, journals, specialty society and manufacturer websites, manual searches of reference sections of RCTs, and published clinical guidelines were performed. Studies were graded for bias. Meta-analytic random effects models were used. Outcomes of interest included: sleep, cardiovascular, mortality, and quality of life (QoL). Grading of recommendations assessment, development and evaluation was performed. Nineteen randomized studies were identified that met the inclusion criteria of apnea hypopnea index (AHI) ≥10, predominant central sleep apnea (CSA), and heart failure with reduced ejection fraction (HFrEF) ≤50%. Most trials examined adaptive servo ventilation (ASV) (8 studies) and continuous positive airway pressure (CPAP) (9 studies). Bias existed in that: 15 of 19 (79%) of the trials lacked blinding, 10 of 19 were manufacturer funded, and with attrition in 8 of 19 studies. In meta-analysis, ASV performed better than control on sleep but not on QoL or cardiovascular outcomes, including mortality. CPAP demonstrated positive short-term outcomes on sleep, cardiovascular, and QoL (3 months). Longer-term cardiovascular and mortality data did not show benefit. Drug therapies demonstrated a positive clinical effect short term on sleep outcomes only. Transvenous phrenic nerve stimulation (TPNS) demonstrated positive treatment outcomes on sleep and QoL at 6 months. Evidence suggests improvement in cardiovascular outcomes with TPNS. In conclusion, ASV and CPAP therapies improve sleep, but long-term QoL or cardiovascular benefit was lacking. TPNS exhibited positive outcomes on sleep and QoL at 6 months with positive trends in CV outcomes.

High-Flow Nasal Cannula versus Noninvasive Positive Pressure Ventilation in Patients with Heart Failure after Extubation: An Observational Cohort Study

Noninvasive positive pressure ventilation (NPPV) has been widely applied in patients with high-risk extubation failure, including heart failure. High-flow nasal cannula (HFNC) has been demonstrated to benefit patients with heart failure by reducing cardiac preload. This study aimed to compare the effectiveness of HFNC to NPPV for preventing extubation failure in patients with heart failure. This 3-year retrospective and single-center cohort study included patients with heart failure with left ventricular ejection fraction <50% who received prophylactic HFNC or NPPV after scheduled extubation from January 2015 to January 2018 from a medical center with four adult intensive care units. Demographics, comorbidities, diagnosis, and weaning status were collected. The primary outcome was treatment failure within 72 hours after extubation, which was defined as escalation to NPPV or reintubation in the HFNC group and was defined as requiring reintubation in the NPPV group. Secondary outcomes were reintubation within 72 hours, reintubation, duration of stay, and mortality during the intensive care unit and hospital stay. Of the 104 patients analyzed, characteristics of 58 patients in the HFNC group and 46 patients in the NPPV group were compared. The treatment failure within 72 hours in the two groups was not significantly different (25.9% vs 13%, p=0.106). Hypoxemic respiratory failure related treatment failure was significantly higher in the HFNC group. Prophylactic HFNC as first-line therapy had a comparable rate of reintubation within 72 hours to the prophylactic NPPV alone (17.2% vs 13%, p=0.556). Other secondary outcomes were similar between the two groups. Among patients with heart failure, HFNC was not inferior to NPPV for preventing extubation failure and reintubation. However, in case of an impending respiratory failure, selective patients may benefit from rescue NPPV.

Adult Patients with Respiratory Distress: Current Evidence-based Recommendations for Prehospital Care

INTRODUCTION

We developed evidence-based recommendations for prehospital evaluation and treatment of adult patients with respiratory distress. These recommendations are compared with current protocols used by the 33 local emergency medical services agencies (LEMSA) in California.

METHODS

We performed a review of the evidence in the prehospital treatment of adult patients with respiratory distress. The quality of evidence was rated and used to form guidelines. We then compared the respiratory distress protocols of each of the 33 LEMSAs for consistency with these recommendations.

RESULTS

PICO (population/problem, intervention, control group, outcome) questions investigated were treatment with oxygen, albuterol, ipratropium, steroids, nitroglycerin, furosemide, and non-invasive ventilation. Literature review revealed that oxygen titration to no more than 94-96% for most acutely ill medical patients and to 88-92% in patients with acute chronic obstructive pulmonary disease (COPD) exacerbation is associated with decreased mortality. In patients with bronchospastic disease, the data shows improved symptoms and peak flow rates after the administration of albuterol. There is limited data regarding prehospital use of ipratropium, and the benefit is less clear. The literature supports the use of systemic steroids in those with asthma and COPD to improve symptoms and decrease hospital admissions. There is weak evidence to support the use of nitrates in critically ill, hypertensive patients with acute pulmonary edema (APE) and moderate evidence that furosemide may be harmful if administered prehospital to patients with suspected APE. Non-invasive positive pressure ventilation (NIPPV) is shown in the literature to be safe and effective in the treatment of respiratory distress due to acute pulmonary edema, bronchospasm, and other conditions. It decreases both mortality and the need for intubation. Albuterol, nitroglycerin, and NIPPV were found in the protocols of every LEMSA. Ipratropium, furosemide, and oxygen titration were found in a proportion of the protocols, and steroids were not prescribed in any LEMSA protocol.

CONCLUSION

Prehospital treatment of adult patients with respiratory distress varies widely across California. We present evidence-based recommendations for the prehospital treatment of undifferentiated adult patients with respiratory distress that will assist with standardizing management and may be useful for EMS medical directors when creating and revising protocols.

In-Hospital Management of Sleep Apnea During Heart Failure Hospitalization: A Randomized Controlled Trial

BACKGROUND

Obstructive sleep apnea (OSA) is associated with increased mortality and readmissions in patients with heart failure (HF). The effect of in-hospital diagnosis and treatment of OSA during decompensated HF episodes remains unknown.

METHODS AND RESULTS

A single-site, randomized, controlled trial of hospitalized patients with decompensated HF (n = 150) who were diagnosed with OSA during the hospitalization was undertaken. All participants received guideline-directed therapy for HF decompensation. Participants were randomized to an intervention arm which received positive airway pressure (PAP) therapy during the hospitalization (n = 75) and a control arm (n = 75). The primary outcome was discharge left ventricular ejection fraction (LVEF). The LVEF changed in the PAP arm from 25.5 ± 10.4 at baseline to 27.3 ± 11.9 at discharge. In the control group, LVEF was 27.3 ± 11.7 at baseline and 28.8 ± 10.5 at conclusion. There was no significant effect on LVEF of in-hospital PAP compared with controls (P = .84) in the intention-to-treat analysis. The on-treatment analysis in the intervention arm showed a significant increase in LVEF in participants who used PAP for ≥3 hours per night (n = 36, 48%) compared with those who used it less (P = .01). There was a dose effect with higher hours of use associated with more improvement in LVEF. Follow-up of readmissions at 6 months after discharge revealed a >60% decrease in readmissions for patients who used PAP ≥3 h/night compared with those who used it <3 h/night (P < .02) and compared with controls (P < .04).

CONCLUSIONS

In-hospital treatment with PAP was safe but did not significantly improve discharge LVEF in patients with decompensated HF and newly diagnosed OSA. An exploratory analysis showed that adequate use of PAP was associated with higher discharge LVEF and decreased 6 months readmissions.

Noninvasive respiratory support in the hypoxaemic peri-operative/periprocedural patient: a joint ESA/ESICM guideline

Hypoxaemia is a potential life-threatening yet common complication in the peri-operative and periprocedural patient (e.g. during an invasive procedure at risk of deterioration of gas exchange, such as bronchoscopy). The European Society of Anaesthesiology (ESA) and the European Society of Intensive Care Medicine (ESICM) developed guidelines for the use of noninvasive respiratory support techniques in the hypoxaemic patient in the peri-operative and periprocedural period. The panel outlined five clinical questions regarding treatment with noninvasive respiratory support techniques [conventional oxygen therapy (COT), high flow nasal cannula, noninvasive positive pressure ventilation (NIPPV) and continuous positive airway pressure (CPAP)] for hypoxaemic patients with acute peri-operative/periprocedural respiratory failure. The goal was to assess the available literature on the various noninvasive respiratory support techniques, specifically studies that included adult participants with hypoxaemia in the peri-operative/periprocedural period. The literature search strategy was developed by a Cochrane Anaesthesia and Intensive Care trial search specialist in close collaboration with the panel members and the ESA group methodologist. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to assess the level of evidence and to grade recommendations. The final process was then validated by both ESA and ESICM scientific committees. Among 19 recommendations, the two grade 1B recommendations state that: in the peri-operative/periprocedural hypoxaemic patient, the use of either NIPPV or CPAP (based on local expertise) is preferred to COT for improvement of oxygenation; and that the panel suggests using NIPPV or CPAP immediately post-extubation for hypoxaemic patients at risk of developing acute respiratory failure after abdominal surgery.

ISCCM Guidelines for the Use of Non-invasive Ventilation in Acute Respiratory Failure in Adult ICUs

A. ACUTE HYPERCAPNIC RESPIRATORY FAILURE A1. Acute Exacerbation of COPD: Recommendations: NIV should be used in management of acute exacerbation of COPD in patients with acute or acute-on-chronic respiratory acidosis (pH = 7.25-7.35). (1A) NIV should be attempted in patients with acute exacerbation of COPD (pH <7.25 & PaCO2 ≥ 45) before initiating invasive mechanical ventilation (IMV) except in patients requiring immediate intubation. (2A). Lower the pH higher the chance of failure of NIV. (2B) NIV should not to be used routinely in normo- or mildly hyper-capneic patients with acute exacerbation of COPD, without acidosis (pH > 7.35). (2B) A2. NIV in ARF due to Chest wall deformities/Neuromuscular diseases: Recommendations: NIV may be used in patients of ARF due to chest wall deformity/Neuromuscular diseases. (PaCO2 ≥ 45) (UPP) A3. NIV in ARF due to Obesity hypoventilation syndrome (OHS): Recommendations: NIV may be used in AHRF in OHS patients when they present with acute hypercapnic or acute on chronic respiratory failure (pH 45). (3B) NIV/CPAP may be used in obese, hypercapnic patients with OHS and/or right heart failure in the absence of acidosis. (UPP) B. NIV IN ACUTE HYPOXEMIC RESPIRATORY FAILURE: B1. NIV in Acute Cardiogenic Pulmonary Oedema: Recommendations: NIV is recommended in hospital patients with ARF, due to Cardiogenic pulmonary edema. (1A). NIV should be used in patients with acute heart failure/ cardiogenic pulmonary edema, right from emergency department itself. (1B) Both CPAP and BiPAP modes are safe and effective in patients with cardiogenic pulmonary edema. (1A). However, BPAP (NIV-PS) should be preferred in cardiogenic pulmonary edema with hypercapnia. (3A) B2. NIV in acute hypoxemic respiratory failure: Recommendations: NIV may be used over conventional oxygen therapy in mild early acute hypoxemic respiratory failure (P/F ratio <300 and >200 mmHg), under close supervision. (2B) We strongly recommend against a trial of NIV in patients with acute hypoxemic failure with P/F ratio <150. (2A) B3. NIV in ARF due to Chest Trauma: Recommendations: NIV may be used in traumatic flail chest along with adequate pain relief. (3B) B4. NIV in Immunocompromised Host: Recommendations: In Immunocompromised patients with early ARF, we may consider NIV over conventional oxygen. (2B). B5. NIV in Palliative Care: Recommendations: We strongly recommend use of NIV for reducing dyspnea in palliative care setting. (2A) B6. NIV in post-operative cases: Recommendations: NIV should be used in patients with post-operative acute respiratory failure. (2A) B6a. NIV in abdominal surgery: Recommendations: NIV may be used in patients with ARF following abdominal surgeries. (2A) B6b. NIV in bariatric surgery: Recommendations: NIV may be used in post-bariatric surgery patients with pre-existent OSA or OHS. (3A) B6c. NIV in Thoracic surgery: Recommendations: In cardiothoracic surgeries, use of NIV is recommended post operatively for acute respiratory failure to improve oxygenation and reduce chance of reintubation. (2A) NIV should not be used in patients undergoing esophageal surgery. (UPP) B6d. NIV in post lung transplant: Recommendations: NIV may be used for shortening weaning time and to avoid re-intubation following lung transplantation. (2B) B7. NIV during Procedures (ETI/Bronchoscopy/TEE/Endoscopy): Recommendations: NIV may be used for pre-oxygenation before intubation. (2B) NIV with appropriate interface may be used in patients of ARF during Bronchoscopy/Endoscopy to improve oxygenation. (3B) B8. NIV in Viral Pneumonitis ARDS: Recommendations: NIV cannot be considered as a treatment of choice for patients with acute respiratory failure with H1N1 pneumonia. However, it may be reasonable to use NIV in selected patients with single organ involvement, in a strictly controlled environment with close monitoring. (2B) B9. NIV and Acute exacerbation of Pulmonary Tuberculosis: Recommendations: Careful use of NIV in patients with acute Tuberculosis may be considered, with effective infection control precautions to prevent air-borne transmission. (3B) B10. NIV after planned extubation in high risk patients: Recommendation: We recommend that NIV may be used to wean high risk patients from invasive mechanical ventilation as it reduces re-intubation rate. (2B) B11. NIV for respiratory distress post extubation: Recommendations: We recommend that NIV therapy should not be used to manage respiratory distress post-extubation in high risk patients. (2B) C. APPLICATION OF NIV: Recommendation: Choice of mode should be mainly decided by factors like disease etiology and severity, the breathing effort by the patient and the operator familiarity and experience. (UPP) We suggest using flow trigger over pressure triggering in assisted modes, as it provides better patient ventilator synchrony. Especially in COPD patients, flow triggering has been found to benefit auto PEEP. (3B) D. MANAGEMENT OF PATIENT ON NIV: D1. Sedation: Recommendations: A non-pharmacological approach to calm the patient (Reassuring the patient, proper environment) should always be tried before administrating sedatives. (UPP) In patients on NIV, sedation may be used with extremely close monitoring and only in an ICU setting with lookout for signs of NIV failure. (UPP) E. EQUIPMENT: Recommendations: We recommend that portable bilevel ventilators or specifically designed ICU ventilators with non-invasive mode should be used for delivering Non–invasive ventilation in critically ill patients. (UPP) Both critical care ventilators with leak compensation and bi-level ventilators have been equally effective in decreasing the WOB, RR, and PaCO2. (3B) Currently, Oronasal mask is the most preferred interface for non-invasive ventilation for acute respiratory failure. (3B) F. WEANING: Recommendations: We recommend that weaning from NIV may be done by a standardized protocol driven approach of the unit. (2B)

How to cite this article: Chawla R, Dixit SB, Zirpe KG, Chaudhry D, Khilnani GC, Mehta Y, et al. ISCCM Guidelines for the Use of Non-invasive Ventilation in Acute Respiratory Failure in Adult ICUs. Indian J Crit Care Med 2020;24(Suppl 1):S61–S81.

Indications for Non-Invasive Ventilation in Respiratory Failure

BACKGROUND

Non-invasive ventilation (NIV) is increasingly being used to treat episodes of acute respiratory failure not only in critical care and respiratory wards, but also in emergency departments.

AIM

Aim of this review is to summarize the current indications for the management of NIV for respiratory failure.

METHODS

Current literature about the topic was reviewed and critically reported to describe the rationale and physiologic advantages of NIV in various situations of respiratory failure.

RESULTS

Early NIV use is commonly associated with the significant decrease in endotracheal intubation rate, the incidence of infective complications (especially ventilatory associated pneumonia), Intensive Care Units and the length of hospital stay and, in selected conditions, also in mortality rates. Severe acute exacerbation of chronic obstructive pulmonary disease (pH<7.35 and relative hypercarbia) and acute cardiogenic pulmonary oedema are the most common NIV indications; in these conditions NIV advantages are clearly documented. Not so evident are the NIV benefits in hypoxaemic respiratory failure occurring without prior chronic respiratory disease (De novo respiratory failure). One recent randomized control trial reported in hypoxaemic respiratory failure a survival benefit of high-flow nasal cannulae over standard oxygen therapy and bilevel NIV. Evidence suggests the advantages of NIV also in respiratory failure in immunocompromised patients or chest trauma patients. Use during a pandemic event has been assessed in several observational studies but remains controversial; there also is not sufficient evidence to support the use of NIV treatment in acute asthma exacerbation.

CONCLUSION

NIV eliminates morbidity related to the endotracheal tube (loss of airway defense mechanism with increased risk of pneumonia) and in selected conditions (COPD exacerbation, acute cardiogenic pulmonary edema, immunosuppressed patients with pulmonary infiltrates and hypoxia) is clearly associated with a better outcome in comparison to conventional invasive ventilation. However, NIV is associated with complications, especially minor complications related to interface. Major complications like aspiration pneumonia, barotrauma and hypotension are infrequent.

Respiratory support in acute heart failure with preserved vs reduced ejection fraction

Background

There is little evidence addressing the use and differential impact of respiratory support in acute heart failure (AHF) patients with preserved (HFPEF) vs reduced (HFREF) ejection fraction. Therefore, our objective was to determine the usage and clinical outcomes of critical care respiratory support in AHF across the two populations.

Hypothesis

Respiratory support would be associated with adverse outcome in both HFPEF and HFREF.

Methods

We identified HFPEF, HFREF, invasive mechanical ventilation (IMV), and noninvasive ventilation (NIV) using International Classification of Disease‐Ninth Edition codes in the National Inpatient Sample between January 1, 2008 and December 31, 2014. We determined rates of IMV and NIV use. We identified predictors of need for IMV and NIV and the association between ventilation strategies and in‐hospital mortality in HFPEF vs HFREF.

Results

1.3 million AHF‐HFPEF and 1.7 million AHF‐HFREF hospitalizations were included; 5.98% of AHF HFPEF hospitalizations included NIV and 0.57% included IMV. Among HFREF hospitalizations, fewer (4.1%) included NIV and more (0.93%) included IMV. In HFPEF hospitalization, NIV use was associated with 2.24‐fold increased risk for death compared to no respiratory support in an adjusted model (HR 2.24 95% CI 2.05‐2.44) and IMV use was associated with 2.85‐fold increased risk for death (HR 2.85 95% CI 2.30‐3.53). This increased risk of in‐hospital mortality was similar among HFREF patients.

Conclusions

Use of respiratory support is increasing among patients with both HFPEF and HFREF and associated with substantially increased mortality in both heart failure subtypes.

National Trends in Incidence and Outcomes of Patients With Heart Failure Requiring Respiratory Support

Despite increasing medical complexity in patients with heart failure (HF), there are limited data on incidence and outcomes for patients with HF needing respiratory support. This study sought to examine contemporary trends of respiratory support strategies among patients with HF. Using the National Inpatient Sample, we identified adults aged greater than 18 years hospitalized with a primary diagnosis of HF. We assessed for trends in the use of invasive mechanical ventilation (IMV) and noninvasive ventilation (NIV), length of stay, hospital costs, and in-hospital mortality. From 2002 to 2014, we identified 9,508,768 HF hospitalizations, which included 202,340 (2.13%) and 257,549 (2.71%) patients that required IMV and NIV, respectively. Over the study period, the proportion of HF patients requiring IMV significantly decreased (3.25% in 2002 to 1.56% in 2014) whereas the use of NIV significantly increased from 0.95% to 7.25% (p_trend <0.001 for both). In-hospital mortality significantly increased for IMV (31.5% in 2002 to 38.6% in 2014) recipients and decreased for patients requiring NIV (9.0% to 5.6%, p_trend <0.0001 for both). The average length of stay was nearly 7 days longer in the IMV group (12.2 days) and 2 days longer in the NIV group (6.8 days; p <0.001 for both). Hospital charges have nearly tripled for patients requiring IMV ($99,358 in 2014, p_trend <0.001) and doubled for those requiring NIV ($37,539 in 2014, p_trend <0.001). In conclusion, respiratory support strategies for patients with HF have significantly evolved with increasing use of NIV as compared with IMV. However, the in-hospital mortality associated with respiratory failure remains unacceptably high.

A comprehensive protocol for ventilator weaning and extubation: a prospective observational study

Background

Ventilator weaning protocols have been shown to reduce the duration of mechanical ventilation (MV), intensive care unit length of stay, and resource use. However, weaning protocols have not significantly affected mortality or reintubation rates. The extubation process is a critical component of respiratory care in patients who receive MV. Post-extubation respiratory failure (PERF) is a common event associated with significant morbidity and mortality. We hypothesized that a comprehensive protocol for ventilator weaning and extubation would be effective for preventing PERF and reintubation and reducing mortality in critically ill patients.

Methods

A ventilator weaning and extubation protocol was developed. The protocol consisted of checklists across four evaluations: spontaneous breathing trial, extubation, prophylactic non-invasive positive pressure ventilation (NPPV), and evaluation after extubation. Observational data were collected after implementing the protocol in patients admitted to the Advanced Emergency and Critical Care Center of Shinshu University Hospital. Not only outcomes of patients but also influences of each component of the protocol on the clinical decision-making process were investigated. Further, a comparison between PERF and non-PERF patients was performed.

Results

A total of 464 consecutive patients received MV for more than 48 h, and 248 (77 women; mean age, 65 ± 17 years) were deemed eligible. The overall PERF and reintubation rates were 9.7% and 5.2%, respectively. Overall, 54.1% of patients with PERF received reintubation. Hospital stay and mortality were not significantly different between PERF and non-PERF patients (p = 0.16 and 0.057, respectively). As a result, the 28-day and hospital mortality were 1.2% and 6.9%, respectively.

Conclusions

We found that the rates of PERF, reintubation, and hospital mortality were lower than those in previous reports even with nearly the same degree of severity at extubation. The comprehensive protocol for ventilator weaning and extubation may prevent PERF and reintubation and reduce mortality in critically ill patients.

Comparison of high-flow nasal cannula oxygen therapy and non-invasive ventilation as first-line therapy in respiratory failure: a multicenter retrospective study

Aim

To identify which subgroups of respiratory failure could benefit more from high‐flow nasal cannula oxygen therapy (HFNC) or non‐invasive ventilation (NIV).

Methods

We undertook a multicenter retrospective study of patients with acute respiratory failure (ARF) who received HFNC or NIV as first‐line respiratory support between January 2012 and December 2017. The adjusted odds ratios (OR) with 95% confidence intervals (CI) for HFNC versus NIV were calculated for treatment failure and 30‐day mortality in the overall cohort and in patient subgroups.

Results

High‐flow nasal cannula oxygen therapy and NIV were used in 200 and 378 patients, and the treatment failure and 30‐day mortality rates were 56% and 34% in the HFNC group and 41% and 39% in the NIV group, respectively. The risks of treatment failure and 30‐day mortality were not significantly different between the two groups. In subgroup analyses, HFNC was associated with increased risk of treatment failure in patients with cardiogenic pulmonary edema (adjusted OR 6.26; 95% CI, 2.19–17.87; P < 0.01) and hypercapnia (adjusted OR 3.70; 95% CI, 1.34–10.25; P = 0.01), but the 30‐day mortality was not significantly different in these subgroups. High‐flow nasal cannula oxygen therapy was associated with lower risk of 30‐day mortality in patients with pneumonia (adjusted OR 0.43; 95% CI, 0.19–0.94; P = 0.03) and in patients without hypercapnia (adjusted OR 0.51; 95% CI, 0.30–0.88; P = 0.02).

Conclusion

High‐flow nasal cannula oxygen therapy could be more beneficial than NIV in patients with pneumonia or non‐hypercapnia, but not in patients with cardiogenic pulmonary edema or hypercapnia.

Inpatient management of acute decompensated heart failure

Acute decompensated heart failure (ADHF) is the leading cause of hospital admissions in patients older than 65 years. These hospitalisations are highly risky and are associated with poor outcomes, including rehospitalisation and death. The management of ADHF is drastically different from that of chronic heart failure as inpatient treatment consists primarily of haemodynamic stabilisation, symptom relief and prevention of short-term morbidity and mortality. In this review, we will discuss the strategies put forth in the most recent American College of Cardiology/American Heart Association and Heart Failure Society of America guidelines for ADHF as well as the evidence behind these recommendations.

Non-Invasive Ventilatory Support In the Elderly

PURPOSE OF REVIEW

The first description of non-invasive ventilation use began in the 1920s. Since then, its role in patient care has evolved through increased clinical knowledge and scientific advancements. The utilization of non-invasive ventilation has broadened from initial application in acute in-hospital ICU settings to now include the outpatient settings. This review discusses the history of non-invasive ventilation and its role in acute in-hospital chronic obstructive pulmonary disease (COPD) exacerbations, cardiogenic pulmonary edema, and weaning from mechanical ventilation in the elderly. The elderly population represents a significant portion of patients hospitalized for the aforementioned conditions. These groups often have more limitations related to the use of invasive mechanical ventilation (IMV), therefore, it is essential to understand the impact of non-invasive ventilation on hospital outcomes.

RECENT FINDINGS

There is strong clinical evidence supporting the use of non-invasive ventilation in patients with respiratory failure secondary to acute COPD exacerbations and cardiogenic pulmonary edema. When compared to standard medical management of these conditions, there is a consistent and significant reduction in the rate of endotracheal intubation and in-hospital mortality.

SUMMARY

The basis of noninvasive ventilation applicability has been determined by significant reduction in mortality and intubation rates. Although survival benefits have been observed, there still remain limitations to the clinical applicability of non-invasive ventilation in certain patient populations and conditions that require further investigation.

Saudi Heart Association (SHA) guidelines for the management of heart failure

Heart failure (HF) is the leading cause of morbidity and mortality worldwide and negatively impacts quality of life, healthcare costs, and longevity. Although data on HF in the Arab population are scarce, recently developed regional registries are a step forward to evaluating the quality of current patient care and providing an overview of the clinical picture. Despite the burden of HF in Saudi Arabia, there are currently no standardized protocols or guidelines for the management of patients with acute or chronic heart failure. Therefore, the Heart Failure Expert Committee, comprising 13 local specialists representing both public and private sectors, has developed guidelines to address the needs and challenges for the diagnosis and treatment of HF in Saudi Arabia. The ultimate aim of these guidelines is to assist healthcare professionals in delivering optimal care and standardized clinical practice across Saudi Arabia.

Emergency care research ethics in low-income and middle-income countries

A large proportion of the total global burden of disease is caused by emergency medical conditions. Emergency care research is essential to improving emergency medicine but this research can raise some distinctive ethical challenges, especially with regard to (1) standard of care and risk–benefit assessment; (2) blurring of the roles of clinician and researcher; (3) enrolment of populations with intersecting vulnerabilities; (4) fair participant selection; (5) quality of consent; and (6) community engagement. Despite the importance of research to improve emergency care in low-income and middle-income countries (LMICs) and the widely acknowledged ethical challenges, very little has been written on the ethics of emergency care research in LMICs. This paper examines the ethical and regulatory challenges to conducting emergency care research with human participants in LMICs. We outline key challenges, present potential solutions or frameworks for addressing these challenges, and identify gaps. Despite the ethical and regulatory challenges, conducting high-quality, ethical emergency care research in LMICs is possible and it is essential for global health.

Acute non-invasive ventilation - getting it right on the acute medical take

Non-invasive ventilation (NIV) given to the right patient, in the right setting, in the right way and at the right time improves outcomes. However, national audits reveal poor practice in patient selection, clinical judgement, treatment initiation and availability of trained staff. NIV is indicated for persistent acute hypercapnic respiratory failure (AHRF) with acidosis after usual medical management in chronic obstructive pulmonary disease (COPD) exacerbation and even without acidosis in neuromuscular disorders or other restrictive conditions eg obesity hypoventilation or kyphoscoliosis. Having trained staff in a suitable environment with adequate equipment are keys to its success, along with close monitoring. A plan should be put in place at the time of initiating NIV about the ceiling of care, eg escalation to intubation or palliation, if the patient is not improving with NIV. Early NIV failure is most likely due to technical issues, such as inadequate pressures or mask leak, while late failure is usually the consequence of advanced disease. Any presentation with AHRF is a poor prognostic indicator and outpatient respiratory follow-up is indicated following discharge. For selected patients with COPD who remain hypercapnic 2 weeks after an exacerbation, domiciliary NIV can reduce admissions and improve survival. For patients with neuromuscular disorders or kyphoscoliosis a presentation with AHRF almost always indicates the need for domiciliary NIV.

External validation of the SAPS3-CNIV score to predict hospital mortality following noninvasive ventilation: a retrospective single-centre study

Prognostication tools are developed to assist clinical decision making and provide valid diagnostic and prognostic outcomes including mortality. Given significant disease and demographic heterogeneity, these tools have to be generally applicable to different patient populations. Therefore, once a model is developed it is internally and externally validated with subsequent clinical impact analyses after which its performance is evaluated and that particular model is then established.

A retrospective single-centre study suggesting that patients with higher SAPS3-CNIV scores may be monitored in an ICU setting in order to reduce adverse patient events and optimal utilisation of resourceshttp://ow.ly/F5qp30o2OT7

Non-invasive positive pressure ventilation (CPAP or bilevel NPPV) for cardiogenic pulmonary oedema

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) has been used to treat respiratory distress due to acute cardiogenic pulmonary oedema (ACPE). We performed a systematic review and meta-analysis update on NPPV for adults presenting with ACPE.

OBJECTIVES

To evaluate the safety and effectiveness of NPPV compared to standard medical care (SMC) for adults with ACPE. The primary outcome was hospital mortality. Important secondary outcomes were endotracheal intubation, treatment intolerance, hospital and intensive care unit length of stay, rates of acute myocardial infarction, and adverse event rates.

SEARCH METHODS

We searched CENTRAL (CRS Web, 20 September 2018), MEDLINE (Ovid, 1946 to 19 September 2018), Embase (Ovid, 1974 to 19 September 2018), CINAHL Plus (EBSCO, 1937 to 19 September 2018), LILACS, WHO ICTRP, and clinicaltrials.gov. We also reviewed reference lists of included studies. We applied no language restrictions.

SELECTION CRITERIA

We included blinded or unblinded randomised controlled trials in adults with ACPE. Participants had to be randomised to NPPV (continuous positive airway pressure (CPAP) or bilevel NPPV) plus standard medical care (SMC) compared with SMC alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected articles for inclusion. We extracted data with a standardised data collection form. We evaluated the risks of bias of each study using the Cochrane 'Risk of bias' tool. We assessed evidence quality for each outcome using the GRADE recommendations.

MAIN RESULTS

We included 24 studies (2664 participants) of adult participants (older than 18 years of age) with respiratory distress due to ACPE, not requiring immediate mechanical ventilation. People with ACPE presented either to an Emergency Department or were inpatients. ACPE treatment was provided in an intensive care or Emergency Department setting. There was a median follow-up of 13 days for hospital mortality, one day for endotracheal intubation, and three days for acute myocardial infarction. Compared with SMC, NPPV may reduce hospital mortality (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.51 to 0.82; participants = 2484; studies = 21; I² = 6%; low quality of evidence) with a number needed to treat for an additional beneficial outcome (NNTB) of 17 (NNTB 12 to 32). NPPV probably reduces endotracheal intubation rates (RR 0.49, 95% CI 0.38 to 0.62; participants = 2449; studies = 20; I² = 0%; moderate quality of evidence) with a NNTB of 13 (NNTB 11 to 18). There is probably little or no difference in acute myocardial infarction (AMI) incidence with NPPV compared to SMC for ACPE (RR 1.03, 95% CI 0.91 to 1.16; participants = 1313; studies = 5; I² = 0%; moderate quality of evidence). We are uncertain as to whether NPPV increases hospital length of stay (mean difference (MD) -0.31 days, 95% CI -1.23 to 0.61; participants = 1714; studies = 11; I² = 55%; very low quality of evidence). Adverse events were generally similar between NPPV and SMC groups, but evidence was of low quality.

AUTHORS' CONCLUSIONS

Our review provides support for continued clinical application of NPPV for ACPE, to improve outcomes such as hospital mortality and intubation rates. NPPV is a safe intervention with similar adverse event rates to SMC alone. Additional research is needed to determine if specific subgroups of people with ACPE have greater benefit of NPPV compared to SMC. Future research should explore the benefit of NPPV for ACPE patients with hypercapnia.

Noninvasive ventilation in critically ill patients with the Middle East respiratory syndrome

Background

Noninvasive ventilation (NIV) has been used in patients with the Middle East respiratory syndrome (MERS) with acute hypoxemic respiratory failure, but the effectiveness of this approach has not been studied.

Methods

Patients with MERS from 14 Saudi Arabian centers were included in this analysis. Patients who were initially managed with NIV were compared to patients who were managed only with invasive mechanical ventilation (invasive MV).

Results

Of 302 MERS critically ill patients, NIV was used initially in 105 (35%) patients, whereas 197 (65%) patients were only managed with invasive MV. Patients who were managed with NIV initially had lower baseline SOFA score and less extensive infiltrates on chest radiograph compared with patients managed with invasive MV. The vast majority (92.4%) of patients who were managed initially with NIV required intubation and invasive mechanical ventilation, and were more likely to require inhaled nitric oxide compared to those who were managed initially with invasive MV. ICU and hospital length of stay were similar between NIV patients and invasive MV patients. The use of NIV was not independently associated with 90‐day mortality (propensity score‐adjusted odds ratio 0.61, 95% CI [0.23, 1.60] P = 0.27).

Conclusions

In patients with MERS and acute hypoxemic respiratory failure, NIV failure was very high. The use of NIV was not associated with improved outcomes.

A pilot study of improvised CPAP (iCPAP) via face mask for the treatment of adult respiratory distress in low-resource settings

BACKGROUND

Continuous positive airway pressure (CPAP) is a mode of non-invasive ventilation used to treat a variety of respiratory conditions in the emergency department and intensive care unit. In low-resource settings where ventilators are not available, the ability to improvise a CPAP system from locally available equipment would provide a previously unavailable means of respiratory support for patients in respiratory distress. This manuscript details the design of such a system and its performance in healthy volunteers.

METHODS

An improvised CPAP system was assembled from standard emergency department equipment and tested in 10 healthy volunteers (6 male, 4 female; ages 29-33). The system utilizes a water seal and high-flow air to create airway pressure; it was set to provide a pressure of 5 cmH2O for the purposes of this pilot study. Subjects used the system in a monitored setting for 30 min. Airway pressure, heart rate, oxygen saturation, and end-tidal CO2 were monitored. Comfort with the device was assessed via questionnaire.

RESULTS

The system maintained positive airway pressure for the full trial period in all subjects, with a mean expiratory pressure (EP) of 5.1 cmH2O (SD 0.7) and mean inspiratory pressure (IP) of 3.2 cmH2O (SD 0.8). There was a small decrease in average EP (5.28 vs 4.88 cmH2O, p = 0.03) and a trend toward decreasing IP (3.26 vs 3.07 cmH2O, p = 0.22) during the trial. No significant change in heart rate, O2 saturation, respiratory rate, or end-tidal CO2 was observed. The system was well tolerated, ranked an average of 4.0 on a 1-5 scale for comfort (with 5 = very comfortable).

CONCLUSIONS

This improvised CPAP system maintained positive airway pressure for 30 min in healthy volunteers. Use did not cause tachycardia, hypoxia, or hypoventilation and was well tolerated. This system may be a useful adjunctive treatment for respiratory distress in low-resource settings. Further research should test this system in settings where other positive pressure modalities are not available.

A real life evaluation of non invasive ventilation in acute cardiogenic pulmonary edema: a multicenter, perspective, observational study for the ACPE SIMEU study group

BACKGROUND

During the past three decades conflicting evidences have been published on the use of non-invasive ventilation (NIV) in patients with acute cardiogenic pulmonary edema (ACPE). The aim of this study is to describe the management of acute respiratory failure (ARF) due to ACPE in twelve Italian emergency departments (EDs). We evaluated prevalence, characteristics and outcomes of ACPE patients treated with oxygen therapy, continuous positive airway pressure (CPAP) or Bi-level positive airway pressure (BiPAP) on admission to the EDs.

METHODS

In this multicenter, prospective, observational study, consecutive adult patients with ACPE were enrolled in 12 EDs in Italy from May 2009 to December 2013. Three study groups were identified according to the initial respiratory treatment: patients receiving oxygen therapy, those treated with CPAP and those treated with BiPAP. Treatment failure was evaluated as study outcome.

RESULTS

We enrolled 1293 patients with acute cardiogenic pulmonary edema. 273 (21%) began with oxygen, 788 (61%) with CPAP and 232 (18%) with BiPAP. One out of four patient who began with oxygen was subsequently switched to NIV and initial treatment with oxygen therapy had an odds ratio for treatment failure of 3.65 (95% CI: 2.55-5.23, p < 0.001).

CONCLUSIONS

NIV seems to be the first choice for treatment of ARF due to ACPE, showing high clinical effectiveness and representing a rescue option for patients not improving with conventional oxygen therapy.

Chinese society of cardiology expert consensus statement on the diagnosis and treatment of adult fulminant myocarditis

Fulminant myocarditis is primarily caused by infection with any number of a variety of viruses. It arises quickly, progresses rapidly, and may lead to severe heart failure or circulatory failure presenting as rapid-onset hypotension and cardiogenic shock, with mortality rates as high as 50%–70%. Most importantly, there are no treatment options, guidelines or an expert consensus statement. Here, we provide the first expert consensus, the Chinese Society of Cardiology Expert Consensus Statement on the Diagnosis and Treatment of Fulminant Myocarditis, based on data from our recent clinical trial (NCT03268642). In this statement, we describe the clinical features and diagnostic criteria of fulminant myocarditis, and importantly, for the first time, we describe a new treatment regimen termed life support-based comprehensive treatment regimen. The core content of this treatment regimen includes (i) mechanical life support (applications of mechanical respirators and circulatory support systems, including intraaortic balloon pump and extracorporeal membrane oxygenation, (ii) immunological modulation by using sufficient doses of glucocorticoid, immunoglobulin and (iii) antiviral reagents using neuraminidase inhibitor. The proper application of this treatment regimen may and has helped to save the lives of many patients with fulminant myocarditis.

Noninvasive ventilation in hypercapnic respiratory failure: from rocking beds to fancy masks

Significant developments have occurred in noninvasive ventilation (NIV) over the past two to three decades, such that it is now one of the most evidence-based areas of respiratory medicine. NIV is now part of the standard of care for a variety of conditions such as hypercapnic respiratory failure due to acute exacerbation of chronic obstructive pulmonary disease (COPD) or cardiogenic pulmonary oedema [1, 2] and it has gained prominence in other settings such as in weaning from invasive mechanical ventilation (IMV), in the postoperative period and in palliative care [3]. Indications for the use of NIV continue to expand.

A chronological account of some of the significant research into the application of NIV in acute hypercapnic respiratory failure over recent decadeshttp://ow.ly/L5bZ30ktEG6

Non-invasive ventilation in cardiogenic pulmonary edema

Cardiogenic pulmonary edema (CPE) is among the most common causes of acute respiratory failure (ARF) in the acute care setting and often requires ventilatory assistance. In patients with ARF due to CPE, use of non-invasive positive airway pressure can decrease the systemic venous return and the left ventricular (LV) afterload, thus reducing LV filling pressure and limiting pulmonary edema. In these patients, either non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) can improve vital signs and physiological parameters, decreasing the need for endotracheal intubation (ETI) and hospital mortality when compared to conventional oxygen therapy. Results on the use of NIV or CPAP in patients with CPE prior to hospitalization are not homogeneous among studies, hampering any conclusive recommendation regarding their role in the pre-hospital setting.

Noninvasive Positive-Pressure Ventilation for Preeclampsia-Induced Pulmonary Edema: 3 Case Reports and a Literature Review

Pulmonary edema caused by severe preeclampsia can be an indication for pregnancy termination. We aimed to investigate whether noninvasive positive-pressure ventilation (NPPV) was useful for preeclampsia-induced pulmonary edema. Three cases of preeclampsia-induced pulmonary edema managed with NPPV in our institute were reviewed retrospectively. A literature review was conducted regarding NPPV usage during pregnancy. NPPV was initiated at 30, 20, and 24 weeks of gestation in the 3 cases. In all cases, NPPV slowed the progression of pulmonary edema and succeeded in delaying pregnancy termination by 17 days on average. Maternal outcomes were positive, and no intubation was required. Between 1994 and 2017, there were 11 articles describing 12 cases in which NPPV was applied for pulmonary edema during pregnancy. However, there has been no case of NPPV management of preeclampsia-induced pulmonary edema thus far. Maternal and fetal outcomes were positive in these 12 cases. NPPV may contribute to prolonging pregnancy in patients with poor oxygenation due to preeclampsia-induced pulmonary edema. However, patients should be closely monitored, and the decision to intubate or terminate the pregnancy should be made without delay when the maternal or fetal condition worsens.

Early decrease of oxidative stress by non-invasive ventilation in patients with acute respiratory failure

Oxidative stress plays an important role in chronic respiratory diseases where the use of non-invasive ventilation seems to reduce the oxidative damage. Data on acute respiratory failure are still lacking. The aim of the study is to investigate the interplay between oxidative stress and acute respiratory failure, and the role of non-invasive ventilation in this setting. We enrolled 60 patients suffering from acute respiratory failure (PaO₂/FiO₂ ratio <300): 30 consecutive patients treated with non-invasive ventilation and 30 consecutive patients treated with conventional oxygen therapy. Serum levels of soluble Nox2-derived peptide (sNOX2-dp), a marker of NADPH-oxidase activation, and 8-iso-PGF2α and H₂O₂, markers of oxidative stress, were evaluated at baseline and after 3 h of treatment. At baseline, higher values of sNOX2-dp, 8-iso-PGF2α and H₂O₂ are associated with lower values of PaO₂/FiO₂ ratio (p < 0.001). After 3 h, serum levels of sNOX2-dp, H₂O₂, and 8-iso-PGF2α significantly decrease in patients treated with non-invasive ventilation, but not in patients treated with conventional oxygen therapy. Delta changes of oxidative stress parameters correlate inversely with the delta changes of PaO₂/FiO₂ (R = -0.623, p < 0.001 for sNOX2-dp; R = -0.428, p < 0.001 for H₂O₂; R = -0.548, p < 0.001 for 8-iso-PGF2α). In the acute respiratory failure setting, treatment with non-invasive ventilation reduces the levels of oxidative stress in the first hours. This reduction is associated with an improvement of PaO₂/FiO₂ ratio as well as in a reduction of NADPH-oxidase activity.

Non-invasive ventilation in the ED: Whom, When, How?

As emergency physicians, we encounter patients suffering from either hypoxemic and/or hypercarbic respiratory problems on a daily basis. A stepwise approach to solving this problem seems logical from an emergency medicine perspective. Current literature supports the notion that NIV decreases endotracheal intubation rates and, mortality in select patient populations. The key to the success of NIV is patient cooperation and support for the care givers. In this narrative review, non-invasive ventilation (NIV) is discussed in terms of modes of delivery, interface and patient selection, as well as practical considerations.

Models and applications for measuring the impact of health research: update of a systematic review for the Health Technology Assessment programme

BACKGROUND

This report reviews approaches and tools for measuring the impact of research programmes, building on, and extending, a 2007 review.

OBJECTIVES

(1) To identify the range of theoretical models and empirical approaches for measuring the impact of health research programmes; (2) to develop a taxonomy of models and approaches; (3) to summarise the evidence on the application and use of these models; and (4) to evaluate the different options for the Health Technology Assessment (HTA) programme.

DATA SOURCES

We searched databases including Ovid MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature and The Cochrane Library from January 2005 to August 2014.

REVIEW METHODS

This narrative systematic literature review comprised an update, extension and analysis/discussion. We systematically searched eight databases, supplemented by personal knowledge, in August 2014 through to March 2015.

RESULTS

The literature on impact assessment has much expanded. The Payback Framework, with adaptations, remains the most widely used approach. It draws on different philosophical traditions, enhancing an underlying logic model with an interpretative case study element and attention to context. Besides the logic model, other ideal type approaches included constructionist, realist, critical and performative. Most models in practice drew pragmatically on elements of several ideal types. Monetisation of impact, an increasingly popular approach, shows a high return from research but relies heavily on assumptions about the extent to which health gains depend on research. Despite usually requiring systematic reviews before funding trials, the HTA programme does not routinely examine the impact of those trials on subsequent systematic reviews. The York/Patient-Centered Outcomes Research Institute and the Grading of Recommendations Assessment, Development and Evaluation toolkits provide ways of assessing such impact, but need to be evaluated. The literature, as reviewed here, provides very few instances of a randomised trial playing a major role in stopping the use of a new technology. The few trials funded by the HTA programme that may have played such a role were outliers.

DISCUSSION

The findings of this review support the continued use of the Payback Framework by the HTA programme. Changes in the structure of the NHS, the development of NHS England and changes in the National Institute for Health and Care Excellence's remit pose new challenges for identifying and meeting current and future research needs. Future assessments of the impact of the HTA programme will have to take account of wider changes, especially as the Research Excellence Framework (REF), which assesses the quality of universities' research, seems likely to continue to rely on case studies to measure impact. The HTA programme should consider how the format and selection of case studies might be improved to aid more systematic assessment. The selection of case studies, such as in the REF, but also more generally, tends to be biased towards high-impact rather than low-impact stories. Experience for other industries indicate that much can be learnt from the latter. The adoption of researchfish^® (researchfish Ltd, Cambridge, UK) by most major UK research funders has implications for future assessments of impact. Although the routine capture of indexed research publications has merit, the degree to which researchfish will succeed in collecting other, non-indexed outputs and activities remains to be established.

LIMITATIONS

There were limitations in how far we could address challenges that faced us as we extended the focus beyond that of the 2007 review, and well beyond a narrow focus just on the HTA programme.

CONCLUSIONS

Research funders can benefit from continuing to monitor and evaluate the impacts of the studies they fund. They should also review the contribution of case studies and expand work on linking trials to meta-analyses and to guidelines.

FUNDING

The National Institute for Health Research HTA programme.

Pharmacological and Non-pharmacological Treatment for Decompensated Heart Failure: What Is New?

PURPOSE OF THE REVIEW

Acute heart failure (AHF) is a life-threatening clinical condition that requires prompt medical attention. The aim of the current review is to summarise the results of recent clinical trials conducted in patients with AHF.

RECENT FINDINGS

Several novel compounds have apparently beneficial acute effects on cardiovascular haemodynamics and patients' symptoms, but their administration has not yet translated into improved survival and has been deleterious in some cases. The management of patients with AHF is challenging and reflects the heterogeneity of patient's presentation, the complexity and severity of a multi-organ syndrome, and the limited therapeutic options, usually restricted to a combination of diuretics and vasodilators. Ongoing trials of novel treatments may provide evidence of an effect on outcomes.

Invasive versus non-invasive ventilation for acute respiratory failure in neuromuscular disease and chest wall disorders

BACKGROUND

Acute respiratory failure is a common life-threatening complication of acute onset neuromuscular diseases, and may exacerbate chronic hypoventilation in patients with neuromuscular disease or chest wall disorders. Standard management includes oxygen supplementation, physiotherapy, cough assistance, and, whenever needed, antibiotics and intermittent positive pressure ventilation. Non-invasive mechanical ventilation (NIV) via nasal, buccal or full-face devices has become routine practice in many centres.

OBJECTIVES

The primary objective of this review was to compare the efficacy of non-invasive ventilation with invasive ventilation in improving short-term survival in acute respiratory failure in people with neuromuscular disease and chest wall disorders. The secondary objectives were to compare the effects of NIV with those of invasive mechanical ventilation on improvement in arterial blood gas after 24 hours and lung function measurements after one month, incidence of barotrauma and ventilator-associated pneumonia, duration of mechanical ventilation, length of stay in the intensive care unit and length of hospital stay.

SEARCH METHODS

We searched the following databases on 11 September 2017: the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE and Embase. We also searched conference proceedings and clinical trials registries.

SELECTION CRITERIA

We planned to include randomised or quasi-randomised trials with or without blinding. We planned to include trials performed in children or adults with acute onset neuromuscular diseases or chronic neuromuscular disease or chest wall disorders presenting with acute respiratory failure that compared the benefits and risks of invasive ventilation versus NIV.

DATA COLLECTION AND ANALYSIS

Two review authors reviewed searches and independently selected studies for assessment. We planned to follow standard Cochrane methodology for data collection and analysis.

MAIN RESULTS

We did not identify any trials eligible for inclusion in the review.

AUTHORS' CONCLUSIONS

Acute respiratory failure is a life-threatening complication of acute onset neuromuscular disease and of chronic neuromuscular disease and chest wall disorders. We found no randomised trials on which to elaborate evidence-based practice for the use of non-invasive versus invasive mechanical ventilation. For researchers, there is a need to design and conduct new randomised trials to compare NIV with invasive ventilation in acute neuromuscular respiratory failure. These trials should anticipate variations in treatment responses according to disease condition (acute onset versus acute exacerbation on chronic neuromuscular diseases) and according to the presence or absence of bulbar dysfunction.

High-flow oxygen via nasal cannulae in patients with acute hypoxemic respiratory failure: a systematic review and meta-analysis

BACKGROUND

We performed a systematic review and meta-analysis to evaluate the efficacy and safety of high-flow oxygen via nasal cannulae (HFNC) compared to non-invasive ventilation (NIV) and/or standard oxygen in patients with acute, hypoxemic respiratory failure.

METHODS

We reviewed randomized controlled trials from CENTRAL, EMBASE, MEDLINE, Scopus and the International Clinical Trials Registry Platform (inception to February 2016), conference proceedings, and relevant article reference lists. Two reviewers independently screened and extracted trial-level data from trials investigating HFNC in patients with acute, hypoxemic respiratory failure. Internal validity was assessed in duplicate using the Cochrane Risk of Bias tool. The strength of evidence was assessed in duplicate using the Grading of Recommendations Assessment, Development and Evaluation framework. Our primary outcome was mortality. Secondary outcomes included dyspnea, PaO2:FiO2 ratio, PaCO2, and pH. Safety outcomes included respiratory arrest, intubation, delirium, and skin breakdown.

RESULTS

From 2023 screened citations, we identified seven trials (1771 patients) meeting inclusion criteria. All trials were at high risk of bias due to lack of blinding. There was no evidence for a mortality difference in patients receiving HFNC vs. NIV and/or standard oxygen (RR 1.01, 95% CI 0.69 to 1.48, I 2 = 63%, five trials, 1629 patients). In subgroup analyses of HFNC compared to NIV or standard oxygen individually, mortality differences were not observed. Measures of patient tolerability were heterogeneous. The PaO2:FiO2 ratio at 6-12 h was significantly lower in patients receiving oxygen via HFNC compared to NIV or standard oxygen for hypoxemic respiratory failure (MD - 53.34, 95% CI - 71.95 to - 34.72, I 2 = 61%, 1143 patients). There were no differences in pH, PaCO2, or rates of intubation or cardio-respiratory arrest. Delirium and skin breakdown were infrequently reported in included trials.

CONCLUSIONS

In patients with acute hypoxemic respiratory failure HFNC was not associated with a difference in mortality compared to NIV or standard oxygen. Secondary outcomes including dyspnea, tolerance, and safety were not systematically reported. Residual heterogeneity and variable reporting of secondary outcomes limit the conclusions that can be made in this review. Prospective trials designed to evaluate the efficacy and safety of HFNC in patients with acute hypoxemic respiratory failure are required.