Official ERS/ATS clinical practice guidelines: noninvasive ventilation for acute respiratory failure

Patient self-inflicted lung injury: implications for acute hypoxemic respiratory failure and ARDS patients on non-invasive support

The role of spontaneous breathing among patients with acute hypoxemic respiratory failure and ARDS is debated: while avoidance of intubation with noninvasive ventilation (NIV) or high-flow nasal cannula improves clinical outcome, treatment failure worsens mortality. Recent data suggest patient self-inflicted lung injury (P-SILI) as a possible mechanism aggravating lung damage in these patients. P-SILI is generated by intense inspiratory effort yielding: (A) swings in transpulmonary pressure (i.e. lung stress) causing the inflation of big volumes in an aerated compartment markedly reduced by the disease-induced aeration loss; (B) abnormal increases in transvascular pressure, favouring negative-pressure pulmonary edema; (C) an intra-tidal shift of gas between different lung zones, generated by different transmission of muscular force (i.e. pendelluft); (D) diaphragm injury. Experimental data suggest that not all subjects are exposed to the development of P-SILI: patients with a PaO2/FiO2 ratio below 200 mmHg may represent the most at risk population. For them, current evidence indicates that high-flow nasal cannula alone may be superior to intermittent sessions of low-PEEP NIV delivered through face mask, while continuous high-PEEP helmet NIV likely promotes treatment success and may mitigate lung injury. The optimal initial noninvasive treatment of hypoxemic respiratory failure/ARDS remains however uncertain; high-flow nasal cannula and high-PEEP helmet NIV are promising tools to enhance success of the approach, but the best balance between these techniques has yet to be identified. During noninvasive support, careful clinical monitoring remains mandatory for prompt detection of treatment failure, in order not to delay intubation and protective ventilation.

European Respiratory Society International Congress 2018: highlights from Assembly 2 on respiratory intensive care

The respiratory intensive care Assembly of the European Respiratory Society is proud to present a summary of several important sessions held at the International Congress in Paris in 2018. For the highly esteemed reader who may have missed the Congress, a concise review was written on three topics: the state-of-the-art session on respiratory critical care, hot topics in weaning and the best abstracts in noninvasive ventilation.

The respiratory intensive care Assembly of the European Respiratory Society is proud to present a summary of several important sessions from the 2018 #ERSCongress in Parishttp://ow.ly/6Du830nFESK

Current Status of Noninvasive Ventilation Use in Korean Intensive Care Units: A Prospective Multicenter Observational Study

Background

Data on noninvasive ventilation (NIV) use in intensive care units (ICUs) are very limited in South Korea.

Methods

A prospective observational study was performed in 20 ICUs of university-affiliated hospitals from June 2017 to February 2018. Adult patients (age>18 years) who were admitted to the ICU and received NIV treatment for acute respiratory failure were included.

Results

A total of 156 patients treated with NIV were enrolled (mean age, 71.9±11.6 years). The most common indications for NIV were acute hypercapnic respiratory failure (AHRF, n=89) and post-extubation respiratory failure (n=44). The main device for NIV was an invasive mechanical ventilator with an NIV module (61.5%), and the majority of patients (87.2%) used an oronasal mask. After the exclusion of 32 do-not-resuscitate patients, NIV success rate was 68.5% (85/124); ICU and hospital mortality rates were 8.9% and 15.3%, respectively. However, the success rate was lower in patients with de novo respiratory failure (27.3%) compared to that of patients with AHRF (72.8%) or post-extubation respiratory failure (75.0%). In multivariate analysis, immunocompromised state, de novo respiratory failure, post-NIV (2 hours) respiratory rate, NIV mode (i.e., non-pressure support ventilation mode), and the change of NIV device were significantly associated with a lower success rate of NIV.

Conclusion

AHRF and post-extubation respiratory failure were the most common indications for NIV in Korean ICUs. Overall NIV success was achieved in 68.5% of patients, with the lowest rate in patients with de novo respiratory failure.

Is positive airway pressure therapy underutilized in chronic obstructive pulmonary disease patients?

INTRODUCTION

The role of noninvasive positive pressure ventilation (NIPPV) in patients with stable chronic obstructive pulmonary disease (COPD) in the home-setting remains controversial. Despite studies suggesting potential benefits, there is an apparent underutilization of such therapy in patients with stable COPD in a domiciliary setting. Areas covered: The reasons for underutilization in the home-setting are multifactorial, and we provide our perspective on the adequacy of scientific evidence and implementation barriers that may underlie the observed underutilization. In this article, we will discuss continuous PAP, bilevel PAP, and non-invasive positive pressure ventilation using a home ventilator (NIPPV). Expert commentary: Many patients with stable COPD and chronic respiratory failure do not receive NIPPV therapy at home despite supportive scientific evidence. Such underutilization suggests that there are barriers to implementation that include provider knowledge, health services, and payor policies. For patients with stable COPD without chronic respiratory failure, there is inadequate scientific evidence to support domiciliary NIPPV or CPAP therapy. In patients with stable COPD without chronic respiratory failure, studies aimed at identifying patient characteristics that determine the effectiveness of domiciliary NIPPV therapy needs further study. Future implementation and health-policy research with appropriate stakeholders are direly needed to help improve patient outcomes.

Acute respiratory failure in immunocompromised adults

Acute respiratory failure occurs in up to half of patients with haematological malignancies and 15% of those with solid tumours or solid organ transplantation. Mortality remains high. Factors associated with mortality include a need for invasive mechanical ventilation, organ dysfunction, older age, frailty or poor performance status, delayed intensive care unit admission, and acute respiratory failure due to an invasive fungal infection or unknown cause. In addition to appropriate antibacterial therapy, initial clinical management aims to restore oxygenation and predict the most probable cause based on variables related to the underlying disease, acute respiratory failure characteristics, and radiographic findings. The cause of acute respiratory failure must then be confirmed using the most efficient, least invasive, and safest diagnostic tests. In patients with acute respiratory failure of undetermined cause, a standardised diagnostic investigation should be done immediately at admission before deciding whether to perform more invasive diagnostic procedures or to start empirical treatments. Collaborative and multidisciplinary clinical and research networks are crucial to improve our understanding of disease pathogenesis and causation and to develop less invasive diagnostic strategies and more targeted treatment options.

NIV for acute respiratory failure in COPD: high in-hospital mortality is determined by patient selection

Introduction: Hospital mortality among chronic obstructive pulmonary disease (COPD) patients receiving NIV for acute respiratory failure has shown to be significantly higher in clinical settings than in the randomized trials (RCTs) which clinical guidelines are based on. This may be due to the quality of care of NIV or patient selection. In daily clinical practice, we include patients with terminal pulmonary disease with a do-not-intubate (DNI) or a do-not-resuscitate (DNR) order with a high mortality risk compared to highly selected patients in RCTs. The aim of this study was to determine the role of patient selection for in-hospital mortality among patients receiving NIV for acute respiratory failure of COPD.

Methods: We conducted a retrospective study including all patients receiving acute NIV due to acute respiratory failure at the respiratory wards in 2012–2013 at two hospitals in Greater Copenhagen.

Results: Overall in-hospital mortality rate was 30%. In patients with a DNI/DNR order, mortality was 59% and in patients with no limitations in treatment 2%. Patients who fulfilled the exclusion criteria of the RCT by Plant et al. had a mortality of 41% compared to 25% in the remaining population.

Conclusions: High overall in-hospital mortality reflects that patient selection in clinical practice is very different from RCT. Quality of acute NIV treatment seems acceptable in clinical practice for patients with less severe COPD and no limitations in treatment. Higher mortality in patients with DNI/DNR order may be due to inefficient NIV treatment for these patients with more severe COPD.

Benefits of non-invasive ventilation in acute hypercapnic respiratory failure

Non-invasive ventilation (NIV) with bilevel positive airway pressure is a non-invasive technique, which refers to the provision of ventilatory support through the patient's upper airway using a mask or similar device. This technique is successful in correcting hypoventilation. It has become widely accepted as the standard treatment for patients with hypercapnic respiratory failure (HRF). Since the 1980s, NIV has been used in intensive care units and, after initial anecdotal reports and larger series, a number of randomized trials have been conducted. Data from these trials have shown that NIV is a valuable treatment for HRF. This review aims to explore the principal areas in which NIV can be useful, focusing particularly on patients with acute HRF (AHRF). We will update the evidence base with the goal of supporting clinical practice. We provide a practical description of the main indications for NIV in AHRF and identify the group of patients with hypercapnic failure who will benefit most from the application of NIV.

Noninvasive Ventilation and Oxygen Therapy after Extubation in Patients with Acute Respiratory Failure: A Meta-analysis of Randomized Controlled Trials

Background

Role of noninvasive ventilation (NIV) following extubation in patients with acute respiratory failure is debatable. NIV may provide benefit in post surgical patients, but its role in nonsurgical patients is controversial.

Materials and methods

PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) were searched (from 1946 to 20^th November 2017) to identify prospective randomized controlled trials, where postextubation NIV has been compared with standard oxygen therapy in adult patients with acute respiratory failure.

Results

Data of 1525 patients from 11 randomized trials have been included in this meta-analysis. Two trials used NIV to manage post-extubation respiratory failure. Pooled analysis found that mortality rate at longest available follow-up [OR (95% CI) 0.84 (0.50, 1.42); p = 0.52] and reintubation rate [OR (95% CI) 0.75 (0.51, 1.09); p = 0.13] were similar between NIV and standard oxygen therapy. NIV did not decrease intubation rate when used as preventive modality [OR (95% CI) 0.65 (0.40, 1.06); p = 0.08]. Duration of ICU stay was also similar in the two groups [MD (95% CI) 0.46 (-0.43, 1.36) days; p = 0.3].

Conclusion

Post extubation NIV in non- surgical patients with acute respiratory failure does not provide any benefit over conventional oxygen therapy.

How to cite this article

Maitra S, Bhattacharjee S, Som A. Noninvasive Ventilation and Oxygen Therapy after Extubation in Patients with Acute Respiratory Failure: A Meta-analysis of Randomized Controlled Trials. Indian J Crit Care Med 2019;23(9):414-422.

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.

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.

High flow nasal therapy in immunocompromised patients with acute respiratory failure: A systematic review and meta-analysis

PURPOSE

The role of high-flow nasal therapy (HFNT) as compared to conventional oxygen therapy (COT) in immunocompromised patients admitted to intensive care unit (ICU) with acute respiratory failure (ARF) remains unclear. We conducted a systematic review and meta-analysis in order to address this issue.

METHODS

We searched PubMed, Medline and Embase until November 7th, 2018. Randomized controlled trials (RCTs), non-randomized prospective and retrospective evidence were selected. Observational studies were considered for sensitivity analysis. Primary outcome was mortality rate; intubation rate was a secondary outcome.

RESULTS

We included four studies in the primary analysis: one RCT, two RCT's post-hoc analyses and one retrospective study. We found no significant difference in short-term mortality comparing HFNT vs. COT: 1) ICU: n = 872 patients, odds ratio (OR) = 0.80 [0.44,1.45], p = 0.46, I² = 30%, p = 0.24; 2) 28-day: n = 996 patients, OR = 0.79 [0.45,1.38], p = 0.40, I² = 52%, p = 0.12). Conversely, we found a reduction of intubation rate in the HFNT group (n = 1052 patients, OR = 0.74 [0.55,0.98], p = 0.03, I² = 7%, p = 0.36). The inclusion of one observational study for sensitivity analysis did not grossly change results.

CONCLUSIONS

We found no benefit of HFNT over COT on mortality in immunocompromised patients with ARF. However, HFNT was associated with a lower intubation rate warranting further research.

Effects of Roflumilast on Rehospitalization and Mortality in Patients

Introduction: Hospitalization for chronic obstructive pulmonary disease (COPD) exacerbation portends the greatest risk of rehospitalization and mortality. Treatments that prevent hospitalizations could significantly lessen COPD morbidity and mortality. Methods: We performed a prospective, randomized, double-blind, placebo-controlled study of roflumilast 500 ug daily versus placebo in patients hospitalized for acute COPD exacerbation. Primary outcome was time to all-cause mortality or non-elective rehospitalization at 180 days post-randomization. Secondary outcomes were death or hospitalization from a respiratory cause, quality of life, change in health status, forced expiratory volume in 1 second (FEV1) and roflumilast tolerance. Results: A total of 64 patients with moderate to severe COPD (FEV1, 37.6 ± 16.4% predicted; 61% female, 61.6 ± 7.9 years old) were assigned to roflumilast or placebo. No deaths occurred in the follow-up period. There was no difference in the time to first readmission between the roflumilast and placebo groups (46.1 days versus 47.3 days respectively, p=0.93). There were 29 and 30 readmissions in the roflumilast and placebo groups, respectively (p=0.47). The St George's Respiratory Questionnaire (SGRQ) decreased 10.8 points and 7.8 points in the roflumilast and placebo groups, respectively and were not different. EuroQuality of Life Five Dimension scale (EQ5D) scores improved, but not significantly in either group. Weight loss and nausea were more common with roflumilast but not different from placebo. Change in glycosylated hemoglobin percentage (HgbA1C%) was not different between groups. Sub-analysis for the impact of chronic bronchitis did not affect outcomes. Conclusion: In this pilot study conducted in patients hospitalized with an exacerbation of COPD, roflumilast did not affect time to all-cause rehospitalization, quality of life, FEV1 or any other measured parameter.

Early extubation followed by immediate noninvasive ventilation vs. standard extubation in hypoxemic patients: a randomized clinical trial

PURPOSE

Noninvasive ventilation (NIV) may facilitate withdrawal of invasive mechanical ventilation (i-MV) and shorten intensive care unit (ICU) length of stay (LOS) in hypercapnic patients, while data are lacking on hypoxemic patients. We aim to determine whether NIV after early extubation reduces the duration of i-MV and ICU LOS in patients recovering from hypoxemic acute respiratory failure.

METHODS

Highly selected non-hypercapnic hypoxemic patients were randomly assigned to receive NIV after early or standard extubation. Co-primary end points were duration of i-MV and ICU LOS. Secondary end points were treatment failure, severe events (hemorrhagic, septic, cardiac, renal or neurologic episodes, pneumothorax or pulmonary embolism), ventilator-associated pneumonia (VAP) or tracheobronchitis (VAT), tracheotomy, percent of patients receiving sedation after study enrollment, hospital LOS, and ICU and hospital mortality.

RESULTS

We enrolled 130 consecutive patients, 65 treatments and 65 controls. Duration of i-MV was shorter in the treatment group than for controls [4.0 (3.0-7.0) vs. 5.5 (4.0-9.0) days, respectively, p = 0.004], while ICU LOS was not significantly different [8.0 (6.0-12.0) vs. 9.0 (6.5-12.5) days, respectively (p = 0.259)]. Incidence of VAT or VAP (9% vs. 25%, p = 0.019), rate of patients requiring infusion of sedatives after enrollment (57% vs. 85%, p = 0.001), and hospital LOS, 20 (13-32) vs. 27(18-39) days (p = 0.043) were all significantly reduced in the treatment group compared with controls. There were no significant differences in ICU and hospital mortality or in the number of treatment failures, severe events, and tracheostomies.

CONCLUSIONS

In highly selected hypoxemic patients, early extubation followed by immediate NIV application reduced the days spent on invasive ventilation without affecting ICU LOS.

Ward-Based Non-Invasive Ventilation in Acute Exacerbations of COPD: A Narrative Review of Current Practice and Outcomes in the UK

Non-invasive ventilation (NIV) is frequently used as a treatment for acute hypercapnic respiratory failure (AHRF) in hospitalised patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). In the UK, many patients with AHRF secondary to AECOPD are treated with ward-based NIV, rather than being treated in critical care. NIV has been increasingly used as an alternative to invasive ventilation and as a ceiling of treatment in patients with a ‘do not intubate’ order. This narrative review describes the evidence base for ward-based NIV in the context of AECOPD and summarises current practice and clinical outcomes in the UK.

Non-invasive ventilation as a strategy for weaning from invasive mechanical ventilation: a systematic review and Bayesian meta-analysis

PURPOSE

A systematic review and meta-analysis was conducted to answer the question 'In adults with respiratory failure requiring invasive ventilation for more than 24 h, does a weaning strategy with early extubation to non-invasive ventilation (NIV) compared to invasive ventilation weaning reduce all-cause hospital mortality?'

METHODS

We included randomised and quasi-randomised controlled trials that evaluated the use of non-invasive ventilation, compared to invasive ventilation, as a weaning strategy in adults mechanically ventilated for at least 24 h. The EMBASE, MEDLINE and Cochrane Central Register of Controlled Trials (CENTRAL) bibliographic databases were searched from inception to February 2018. Bayesian hierarchical models were used to perform the meta-analysis. The primary outcome was mortality at hospital discharge. Secondary outcomes included mortality (30, 60, 90 and 180 days), quality of life, duration of invasive ventilation, weaning failure, length of stay [intensive care unit (ICU) and hospital] and adverse events.

RESULTS

Twenty-five relevant studies involving 1609 patients were included in the quantitative analysis. Studies had moderate to high risk of bias due to risk of performance and detection bias. Mortality at hospital discharge was lower in the NIV weaning group compared to the invasive weaning group [pooled odds ratio (OR) 0.58, 95% highest density interval (HDI) 0.29-0.89]. Subgroup analyses showed lower pooled mortality at hospital discharge rates in NIV weaning than those in the control group in chronic obstructive pulmonary disease (COPD) patients (pooled OR 0.43, 95% HDI 0.13-0.81) and the effect is less certain in the mixed ICU population (pooled OR 0.88, 95% HDI 0.25-1.48). NIV weaning reduced the duration of invasive ventilation in patients [standardised mean difference (SMD) - 1.34, 95% HDI - 1.92 to - 0.77] and ICU length of stay (SMD - 0.70, 95% HDI - 0.94 to - 0.46). Reported rates of ventilator associated pneumonia (VAP) were lower in the NIV group. NIV weaning did not reduce overall hospital length of stay or long-term mortality. There were insufficient data to compare other adverse events and health-related quality of life.

CONCLUSIONS

The use of NIV in weaning from mechanical ventilation decreases hospital mortality, the incidence of VAP and ICU length of stay. NIV as a weaning strategy appears to be most beneficial in patients with COPD.

Non-invasive ventilation: Essential requirements and clinical skills for successful practice

Audits and case reviews of the acute delivery of non-invasive ventilation (NIV) have shown that the results achieved in real life often fall short of those achieved in research trials. Factors include inappropriate selection of patients for NIV and failure to apply NIV correctly. This highlights the need for proper training of all involved individuals. This article addresses the different skills needed in a team to provide an effective NIV service. Some detail is given in each of the key areas but it is not comprehensive and should stimulate further learning (reading, attendance on courses, e-learning, etc.), determined by the needs of the individual.

High flow nasal therapy in perioperative medicine: from operating room to general ward

BACKGROUND

High flow nasal therapy (HFNT) is a technique in which humidified and heated gas is delivered to the airways through the nose via small nasal prongs at flows that are higher than the rates generally applied during conventional oxygen therapy. The delivered high flow rates combine mixtures of air and oxygen and enable different inspired oxygen fractions ranging from 0.21 to 1. HFNT is increasingly used in critically ill adult patients, especially hypoxemic patients in different clinical settings.

MAIN BODY

Noninvasive ventilation delivers positive pressure (end-expiratory and inspiratory pressures or continuous positive airway pressure) via different external interfaces. In contrast, HFNT produces different physiological effects that are only partially linked to the generation of expiratory positive airway pressure. HFNT and noninvasive ventilation (NIV) are interesting non-invasive supports in perioperative medicine. HFNT exhibits some advantages compared to NIV because HFNT is easier to apply and requires a lower nursing workload. Tolerance of HFNT remains a matter of intense debate, and it may be related to selected parameters. Patients receiving HFNT and their respiratory patterns should be closely monitored to avoid delays in intubation despite correct oxygenation parameters.

CONCLUSION

HFNT seems to be an interesting noninvasive support in perioperative medicine. The present review provides anesthesiologists with an overview of current evidence and practical advice on the application of HFNT in perioperative medicine in adult patients.

Non-invasive ventilation or high-flow oxygen therapy: When to choose one over the other?

It has been found that high-flow oxygen therapy (HFOT) can reduce mortality of patients admitted to intensive care unit (ICU) for de novo acute respiratory failure (ARF) as compared to non-invasive ventilation (NIV). HFOT might therefore be considered as a first-line strategy of oxygenation in these patients. The beneficial effects of HFOT may be explained by its good tolerance and by physiological characteristics including delivery of high FiO₂ , positive end expiratory pressure (PEEP) effect and continuous dead space washout contributing to decreased work of breathing. In contrast, NIV should be used cautiously in patients with de novo ARF due to high tidal volumes promoted by pressure support and that may potentially worsen pre-existing lung injury. Although recent studies have reported no benefit and even deleterious effects of NIV in immunocompromised patients with ARF, the experts have recommended its use as a first-line strategy. In patients with acute-on-chronic respiratory failure and respiratory acidosis, it has been clearly shown that NIV is the best strategy of oxygenation. However, HFOT seems able to reverse respiratory acidosis and further studies are needed to evaluate whether HFOT could represent an alternative to standard oxygen. Although NIV is recommended to treat ARF in post-operative patients or to prevent post-extubation respiratory failure in ICU, recent large-scale randomized studies suggest that HFOT could be equivalent to NIV. While recent recommendations have been established from studies comparing NIV with standard oxygen, new studies are needed to compare NIV versus HFOT in order to better define the appropriate indications for both treatments.

Obstructive sleep apnea in patients surviving acute hypercapnic respiratory failure is best predicted by static hyperinflation

Rationale

Acute hypercapnic respiratory failure (AHRF) treated with non-invasive ventilation in the ICU is frequently caused by chronic obstructive pulmonary disease (COPD) exacerbations and obesity-hypoventilation syndrome, the latter being most often associated with obstructive sleep apnea. Overlap syndrome (a combination of COPD and obstructive sleep apnea) may represent a major burden in this population, and specific diagnostic pathways are needed to improve its detection early after ICU discharge.

Objectives

To evaluate whether pulmonary function tests can identify a high probability of obstructive sleep apnea in AHRF survivors and outperform common screening questionnaires to identify the disorder.

Methods

Fifty-three patients surviving AHRF (31 males; median age 67 years (interquartile range: 62–74) participated in the study. Anthropometric data were recorded and body plethysmography was performed 15 days after ICU discharge. A sleep study was performed 3 months after ICU discharge.

Results

The apnea-hypopnea index was negatively associated with static hyperinflation as measured by the residual volume to total lung capacity ratio in the % of predicted (coefficient = -0.64; standard error 0.17; 95% CI -0.97 to -0.31; p<0.001). A similar association was observed in COPD patients only: coefficient = -0.65; standard error 0.19; 95% CI -1.03 to -0.26; p = 0.002. Multivariate analysis with penalized maximum likelihood confirmed that the residual volume to total lung capacity ratio was the main contributor for apnea-hypopnea index variance in addition to classic predictors. Screening questionnaires to select patients at risk for sleep-disordered breathing did not perform well.

Conclusions

In AHRF survivors, static hyperinflation is negatively associated with the apnea-hypopnea index in both COPD and non-COPD patients. Measuring static hyperinflation in addition to classic predictors may help to increase the recognition of obstructive sleep apnea as common screening tools are of limited value in this specific population.

Noninvasive ventilation in acute hypoxemic respiratory failure: A systematic review and meta-analysis

PURPOSE

Evaluate current recommendation for the use of noninvasive ventilation (Bi-level positive airway pressure- BiPAP modality) in hypoxemic acute respiratory failure, excluding chronic obstructive pulmonary disease.

METHODS

Electronic searches in MEDLINE, Web of Science, Clinical Trials, and The Cochrane Central Register of Controlled Clinical Trials. We searched for randomized controlled trials comparing BiPAP to a control group in patients with hypoxemic acute respiratory failure. Endotracheal intubation and death were the assessed outcomes.

RESULTS

Of the 563 studies found, nine met the inclusion criteria for this systematic review. The pooled RR (95% CI) for intubation in patients with acute pulmonary edema (APE)/community acquired pneumonia (CAP) and in immunosuppressed patients (cancer and transplants) were 0.61 (0.39-0.84) and 0.77 (0.60-0.93), respectively. For Intensive Care Units (ICU) mortality, the RR (95% CI) in patients with APE/CAP was 0.51 (0.22-0.79). The heterogeneity was low in all comparisons.

CONCLUSIONS

NIV showed a significant protective effect for intubation in immunosuppressed patients (cancer and transplants) and in patients with APE/CAP. However, the benefits of NIV for other etiologies are not clear and more trials are needed to prove these effects.

High-flow nasal therapy vs standard oxygen during breaks off noninvasive ventilation for acute respiratory failure: A pilot randomized controlled trial

PURPOSE

To assess the role of high-flow nasal therapy (HFNT) compared to standard oxygen (SO) as complementary therapy to non-invasive ventilation (NIV).

METHODS

Multicenter trial including patients (n = 54) anticipated to receive NIV for ≥24 h due to acute or acute-on-chronic respiratory failure. Subjects were randomized (1:1) to SO or HFNT during breaks off NIV. Primary outcome was total time on and off NIV. Secondary outcomes were comfort and dyspnea, respiratory rate (RR), oxygen saturation (S_pO₂), tolerance and side effects.

RESULTS

Total time per patient on NIV (1315 vs 1441 min) and breaks (1362 vs 1196 min), and mean duration of each break (520 vs 370 min) were similar in the HFNT and SO arms (p > .05). Comfort score was higher on HFNT than on SO (8.3 ± 2.7 vs 6.9 ± 2.3, p = .001). Dyspnea, RR and S_pO₂ were similar in the two arms, but the increase in RR and dyspnea seen with SO during breaks did not occur with HFNT.

CONCLUSION

Compared to SO, HFNT did not reduce time on NIV. However, it was more comfortable and the increase in RR and dyspnea seen with SO did not occur with HFNT. Therefore, HFNT could be a suitable alternative to SO during breaks off NIV.

Management of severe acute exacerbations of COPD: an updated narrative review

Background

Patients with chronic obstructive pulmonary disease (COPD) may experience an acute worsening of respiratory symptoms that results in additional therapy; this event is defined as a COPD exacerbation (AECOPD). Hospitalization for AECOPD is accompanied by a rapid decline in health status with a high risk of mortality or other negative outcomes such as need for endotracheal intubation or intensive care unit (ICU) admission. Treatments for AECOPD aim to minimize the negative impact of the current exacerbation and to prevent subsequent events, such as relapse or readmission to hospital.

Main body

In this narrative review, we update the scientific evidence about the in-hospital pharmacological and non-pharmacological treatments used in the management of a severe AECOPD. We review inhaled bronchodilators, steroids, and antibiotics for the pharmacological approach, and oxygen, high flow nasal cannulae (HFNC) oxygen therapy, non-invasive mechanical ventilation (NIMV) and pulmonary rehabilitation (PR) as non-pharmacological treatments. We also review some studies of non-conventional drugs that have been proposed for severe AECOPD.

Conclusion

Several treatments exist for severe AECOPD patients requiring hospitalization. Some treatments such as steroids and NIMV (in patients admitted with a hypercapnic acute respiratory failure and respiratory acidosis) are supported by strong evidence of their efficacy. HFNC oxygen therapy needs further prospective studies. Although antibiotics are preferred in ICU patients, there is a lack of evidence regarding the preferred drugs and optimal duration of treatment for non-ICU patients. Early rehabilitation, if associated with standard treatment of patients, is recommended due to its feasibility and safety. There are currently few promising new drugs or new applications of existing drugs.

Survey on accessibility and real-life application of noninvasive ventilation

Noninvasive mechanical ventilation (NIV) is an accepted method of respiratory failure treatment; however, at present, little is known about the global factors limiting NIV application. A survey designed to determine NIV accessibility and limiting factors in world economies and regions was developed. The questionnaire was sent to members of the European Respiratory Society (ERS) Respiratory Intensive Care Assembly and all ERS National Delegates. Replies to the survey were collected from 161 respondents from 46 countries. NIV was found to be provided most frequently by pulmonologists and intensivists. In high-income economies (HIEs), NIV reimbursement in chronic respiratory failure treatment was found to be independent of the underlying disease and supplementary insurance (p<0.0001), whereas in upper-middle-income economies (UMIEs) it was found to be dependent on the underlying disease (p<0.0001). In chronic respiratory failure, NIV was not reimbursed in lower-middle-income economies (LMIEs) (p<0.0001). In LMIEs and UMIEs, the lack of financial resources was the main limiting factor in acute (p=0.007) and chronic respiratory failure (p<0.0001). In the income-level-based assessment, financing was recognised as relevant in LMIEs and UMIEs (p<0.0001), equipment in LMIEs and UMIEs (p=0.03), medical staff in all economies (p=0.02), and legal regulations in LMIEs (p=0.0005). It was confirmed that NIV in acute and chronic respiratory failure is reimbursed based on government regulations in UMIEs and HIEs (p<0.0001), and is not reimbursed and probably will not be reimbursed in the near future in LMIEs (p<0.0001). We conclude that financial constraints are still considered a major limiting factor for NIV use.

Oxygenation/non-invasive ventilation strategy and risk for intubation in immunocompromised patients with hypoxemic acute respiratory failure

We investigated how the initial ventilation/oxygenation management may influence the need for intubation on the coming day in a cohort of immunocompromised patients with acute hypoxemic respiratory failure (ARF).

Data from 847 immunocompromised patients with ARF were used to estimate the probability of intubation at day+1 within the first 3 days of ICU admission, according to oxygenation management. First, noninvasive ventilation (NIV) was compared to oxygen therapy whatever the administration device; then standard oxygen was compared to High Flow Nasal Cannula therapy alone (HFNC), NIV alone or NIV+HFNC. To take into account the oxygenation regimens over time and to handle confounders, propensity score weighting models were used.

In the original sample, the probability of intubation at day+1 was higher in the NIV group vs oxygenation therapy (OR = 1.64, 95CI, 1.09–2.48) or vs the standard oxygen group (OR = 2.05, 95CI: 1.29–3.29); it was also increased in the HFNC group compared to standard oxygen (OR = 2.85, 95CI: 1.37–5.67). However, all these differences disappeared by handling confounding-by-indication in the weighted samples, as well as in the pooled model. Note that adjusted OR for day-28 mortality increased with the day of intubation.

In this large cohort of immunocompromised patients, ventilation/oxygenation management had no impact on the probability of intubation on the coming day.

Perioperative lung protective ventilation

Perioperative lung injury is a major source of postoperative morbidity, excess healthcare use, and avoidable mortality. Many potential inciting factors can lead to this condition, including intraoperative ventilator induced lung injury. Questions exist as to whether protective ventilation strategies used in the intensive care unit for patients with acute respiratory distress syndrome are equally beneficial for surgical patients, most of whom do not present with any pre-existing lung pathology. Studied both individually and in combination as a package of intraoperative lung protective ventilation, the use of low tidal volumes, moderate positive end expiratory pressure, and recruitment maneuvers have been shown to improve oxygenation and pulmonary physiology and to reduce postoperative pulmonary complications in at risk patient groups. Further work is needed to define the potential contributions of alternative ventilator strategies, limiting excessive intraoperative oxygen supplementation, use of non-invasive techniques in the postoperative period, and personalized mechanical ventilation. Although the weight of evidence strongly suggests a role for lung protective ventilation in moderate risk patient groups, definitive evidence of its benefit for the general surgical population does not exist. However, given the shift in understanding of what is needed for adequate oxygenation and ventilation under anesthesia, the largely historical arguments against the use of intraoperative lung protective ventilation may soon be outdated, on the basis of its expanding track record of safety and efficacy in multiple settings.

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

High-flow nasal cannula oxygen therapy alone or with non-invasive ventilation during the weaning period after extubation in ICU: the prospective randomised controlled HIGH-WEAN protocol

INTRODUCTION

Recent practice guidelines suggest applying non-invasive ventilation (NIV) to prevent postextubation respiratory failure in patients at high risk of extubation failure in intensive care unit (ICU). However, such prophylactic NIV has been only a conditional recommendation given the low certainty of evidence. Likewise, high-flow nasal cannula (HFNC) oxygen therapy has been shown to reduce reintubation rates as compared with standard oxygen and to be as efficient as NIV in patients at high risk. Whereas HFNC may be considered as an optimal therapy during the postextubation period, HFNC associated with NIV could be an additional means of preventing postextubation respiratory failure. We are hypothesising that treatment associating NIV with HFNC between NIV sessions may be more effective than HFNC alone and may reduce the reintubation rate in patients at high risk.

METHODS AND ANALYSIS

This study is an investigator-initiated, multicentre randomised controlled trial comparing HFNC alone or with NIV sessions during the postextubation period in patients at high risk of extubation failure in the ICU. Six hundred patients will be randomised with a 1:1 ratio in two groups according to the strategy of oxygenation after extubation. The primary outcome is the reintubation rate within the 7 days following planned extubation. Secondary outcomes include the number of patients who meet the criteria for moderate/severe respiratory failure, ICU length of stay and mortality up to day 90.

ETHICS AND DISSEMINATION

The study has been approved by the ethics committee and patients will be included after informed consent. The results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03121482.

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.

High-flow nasal cannula oxygen therapy decreases postextubation neuroventilatory drive and work of breathing in patients with chronic obstructive pulmonary disease

BACKGROUND

The physiological effects of high-flow nasal cannula O₂ therapy (HFNC) have been evaluated mainly in patients with hypoxemic respiratory failure. In this study, we compared the effects of HFNC and conventional low-flow O₂ therapy on the neuroventilatory drive and work of breathing postextubation in patients with a background of chronic obstructive pulmonary disease (COPD) who had received mechanical ventilation for hypercapnic respiratory failure.

METHODS

This was a single center, unblinded, cross-over study on 14 postextubation COPD patients who were recovering from an episode of acute hypercapnic respiratory failure of various etiologies. After extubation, each patient received two 1-h periods of HFNC (HFNC1 and HFNC2) alternated with 1 h of conventional low-flow O₂ therapy via a face mask. The inspiratory fraction of oxygen was titrated to achieve an arterial O₂ saturation target of 88-92%. Gas exchange, breathing pattern, neuroventilatory drive (electrical diaphragmatic activity (EAdi)) and work of breathing (inspiratory trans-diaphragmatic pressure-time product per minute (PTP_DI/min)) were recorded.

RESULTS

EAdi peak increased from a mean (±SD) of 15.4 ± 6.4 to 23.6 ± 10.5 μV switching from HFNC1 to conventional O₂, and then returned to 15.2 ± 6.4 μV during HFNC2 (conventional O₂: p < 0.05 versus HFNC1 and HFNC2). Similarly, the PTP_DI/min increased from 135 ± 60 to 211 ± 70 cmH₂O/s/min, and then decreased again during HFNC2 to 132 ± 56 (conventional O₂: p < 0.05 versus HFNC1 and HFNC2).

CONCLUSIONS

In patients with COPD, the application of HFNC postextubation significantly decreased the neuroventilatory drive and work of breathing compared with conventional O₂ therapy.

Noninvasive ventilation in acute respiratory failure: which recipe for success?

Noninvasive positive-pressure ventilation (NPPV) to treat acute respiratory failure has expanded tremendously over the world in terms of the spectrum of diseases that can be successfully managed, the locations of its application and achievable goals.

The turning point for the successful expansion of NPPV is its ability to achieve the same physiological effects as invasive mechanical ventilation with the avoidance of the life-threatening risks correlated with the use of an artificial airway.

Cardiorespiratory arrest, extreme psychomotor agitation, severe haemodynamic instability, nonhypercapnic coma and multiple organ failure are absolute contraindications for NPPV. Moreover, pitfalls of NPPV reduce its rate of success; consistently, a clear plan of what to do in case of NPPV failure should be considered, especially for patients managed in unprotected setting. NPPV failure is likely to be reduced by the application of integrated therapeutic tools in selected patients handled by expert teams.

In conclusion, NPPV has to be considered as a rational art and not just as an application of science, which requires the ability of clinicians to both choose case-by-case the best “ingredients” for a “successful recipe” (i.e.patient selection, interface, ventilator, interface,etc.) and to avoid a delayed intubation if the ventilation attempt fails.

Oxygen Treatment in Intensive Care and Emergency Medicine

BACKGROUND

Oxygen treatment is often life-saving, but multiple studies in recent years have yielded evidence that the indiscriminate administration of oxygen to patients in the intensive care unit and emergency room can cause hyperoxia and thereby elevate mortality.

METHODS

This review is based on prospective, randomized trials concerning the optimum use of oxygen in adult medicine, which were retrieved by a selective search in PubMed, as well as on pertinent retrospective studies and guideline recommendations.

RESULTS

13 prospective, randomized trials involving a total of 17 213 patients were analyzed. In patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) and in ventilated intensive-care patients, normoxia was associated with a lower mortality than hyperoxia (2% vs. 9%). In patients with myocardial infarction, restrictive oxygen administration was associated with a smaller infarct size on cardiac MRI at 6 months compared to oxygen administration at 8 L/min (13.1 g vs. 20.3 g). For patients with stroke, the currently available data do not reveal any benefit or harm from oxygen administration. None of the trials showed any benefit from the administration of oxygen to non-hypoxemic patients; in fact, this was generally associated with increased morbidity or mortality.

CONCLUSION

Hypoxemia should certainly be avoided, but the fact that the liberal administration of oxygen to patients in intensive care units and emergency rooms tends to increase morbidity and mortality implies the advisability of a conservative, normoxic oxygenation strategy.

Nurses' and physicians' knowledge and skills in non-invasive ventilation: Equipment and contextual influences

OBJECTIVES

To assess non-invasive ventilation knowledge and skills among nurses and physicians in different contexts: equipment and contextual influences.

METHOD

Cross-sectional, descriptive study in 4 intensive care units (ICU) (1 surgical, 3 medical-surgical), 1 postsurgical recovery unit, 2 emergency departments (ED) and 3 wards, in 4 hospitals (3 university, 1 community) with 407 professionals. A 13-item survey, validated in the setting, was applied (Kappa index, 0.97 (95% CI [.965-.975]).

RESULTS

Nurses (63.7% response); physicians (39% response). The overall percentage of correct responses was 50%. Scored from 1 to 5, with lower scores reflecting more knowledge, nurses scored 3.27±.5 vs 2.62±.5 physicians, respectively (mean difference,.65 (95% CI: .48-.82, P<.001). There were no differences between hospitals or units (P=.07 and P=.09). A notable percentage of respondents incorrectly identified the patient-ventilator synchronization strategy as "covering the expiratory port" (intentional leaks) and pressing the mask against the patient's face (unintentional leaks) (28.2% ICU, 22.5% ED, 8.3% postoperative resuscitation, 61.5% wards), with no difference between nurses and physicians (27.9% vs 23.4%, P=.6). Only 50% of nurse respondents correctly answered a question about measuring mask size and just 11.7% of the nurses knew the "2-finger fit" adjustment.

CONCLUSIONS

There was no difference in nurses' and physicians' knowledge according to the setting studied. The lack of knowledge regarding NIV therapy depended on training received and material available. To reduce the existent confusion between intentional and nonintentional leak, the use of a single type of NIV supply and providing an appropriate level of training for nurses is recommended.