High pressure versus high intensity noninvasive ventilation in stable hypercapnic chronic obstructive pulmonary disease: a randomized crossover trial

Home Noninvasive Ventilation in COPD

Evidence is increasing that long-term noninvasive ventilation (LTNIV) can improve outcomes in individuals with severe, hypercapnic COPD. Although the evidence remains unclear in some aspects, LTNIV seems to be able to improve patient-related and physiologic outcomes like dyspnea, FEV1 and partial pressure of carbon dioxide (Pco2) and also to reduce rehospitalizations and mortality. Efficacy generally is associated with reduction in Pco2. To achieve this, an adequate interface (mask) is essential, as are appropriate ventilation settings that target the specific respiratory physiologic features of COPD. This will ensure comfort, synchrony, and adherence that will result in physiologic improvements. This article briefly reviews the newest evidence and current guidelines on LTNIV in severe COPD. It describes an actual patient who benefitted from the therapy. Finally, it provides strategies for initiating and optimizing this LTNIV in COPD, discussing high-pressure noninvasive ventilation, optimization of triggering, and control of inspiratory time. As demand increases, clinicians will need to be familiar with this therapy to reap its benefits, because inadequately adjusted LTNIV will not be tolerated or effective.

A history of home mechanical ventilation: The past, present and future

This state-of-the-art review provides an overview of the history of home mechanical ventilation (HMV), including early descriptions of mechanical ventilation from ancient and Renaissance perspectives and the mass development of ventilators designed for long-term use during the poliomyelitis epidemic. Seminal data from key clinical trials supports the application of HMV in certain patients with chronic obstructive pulmonary disease, neuromuscular disease and obesity-related respiratory failure. Innovative engineering coupled with refined physiological understanding now permits widespread delivery of home mechanical ventilation to a global population, using portable devices with advanced ventilatory modes and telemonitoring capabilities. Exponential growth in digital technology continues, and ongoing research is needed to understand how to harness clinical and physiological data to benefit patients and healthcare services in a clinically- and cost-effective manner.

Noninvasive Home Mechanical Ventilation for Stable Hypercapnic COPD: A Clinical Respiratory Review from Canadian Perspectives

Acute short-term noninvasive ventilation (NIV) for hypercapnic respiratory failure in chronic obstructive pulmonary disease (COPD) has well-established benefits; however, the role of long-term home NIV remains controversial. In the past decade, studies utilizing aggressive NIV settings to maximally reduce carbon dioxide levels (PaCO2) have resulted in several positive clinical trials and led to updated guidelines on home NIV for stable hypercapnic COPD patients. This clinical respiratory review discusses the high-intensity NIV approach, summarizes recent key trials and guidelines pertaining to home NIV in COPD, and considers key clinical questions for future research and application in the Canadian context. With recent evidence and Canadian Thoracic Society (CTS) guidelines supporting the use of NIV in carefully selected COPD patients with persistent daytime hypercapnia, we believe it is time to reconsider our approach.

Home Noninvasive Ventilation for COPD

Patients with hypercapnic COPD appear to represent a phenotype driven by specific physiology including air trapping and mechanical disadvantage, sleep hypoventilation, and sleep apnea. Such individuals appear to be at high risk for adverse health outcomes. Home noninvasive ventilation (NIV) has been shown to have the potential to help compensate for physiological issues underlying hypercapnia. In contrast to older literature, contemporary clinical trials of home NIV have been shown to improve patient-oriented outcomes including quality of life, hospitalizations, and mortality. Advancements in the use of NIV, including the use of higher inspiratory pressures, may account for recent success. Successful practical application of home NIV thus requires an adequate understanding of patient selection, devices and modes, and strategies for titration. The emergence of telemonitoring holds promise for further improvements in patient care by facilitating titration, promoting adherence, troubleshooting issues, and possibly predicting exacerbations. Given the complexity of home NIV, clinicians and health systems might consider establishment of dedicated home ventilation programs to provide such care. In addition, incorporation of respiratory therapist expertise is likely to improve success. Traditional fee-for-service structures have been a challenge for financing such programs, but ongoing changes toward value-based care are likely to make home NIV programs more feasible.

Does one size fit all? An update on chronic ventilatory support in different respiratory illnesses

Home noninvasive ventilation (HNIV) improves outcomes in different disease categories. In this article, we discuss indications for when and how to initiate HNIV in COPD, obesity hypoventilation syndrome (OHS) and neuromuscular disorders (NMD). While in COPD, significant diurnal hypercapnia and high-intensity HNIV are essential ingredients for success, in NMD and OHS, early respiratory changes are best detected during sleep through oxy-capnography associated (or not) with respiratory polygraphy. In COPD and OHS, it is crucial to consider the coexistence of obstructive sleep apnoea because treatment with continuous positive airway pressure may be the simplest and most effective treatment that should be proposed even in hypercapnic patients as first-line therapy. In NMD, the need for continuous HNIV and eventual switching to tracheostomy ventilation makes this group's management more challenging. Achieving successful HNIV by improving quality of sleep, quality of life and keeping a good adherence to the therapy is a challenge, above all in COPD patients. In OHS patients, on top of HNIV, initiation of other interventions such as weight loss management is crucial. More resources should be invested in improving all these aspects. Telemonitoring represents a promising method to improve titration and follow-up of HNIV.

Getting It Right in Obstructive Lung Disease

Chronic hypercapnic respiratory failure in obstructive lung diseases may benefit from nocturnal Home non-invasive ventilation (HNIV). It has been shown that in patients with persistence of hypercapnia after an acute episode of chronic obstructive pulmonary disease (COPD) exacerbation requiring mechanical ventilation, HNIV may improve the risk for new admission and survival. The ability to reach these aims depends on the correct timing of enrolling patients, as well as a correct definition of ventilatory needing and setting of the ventilator. This review tries to define a possible home treatment path of hypercapnic respiratory failure in COPD by analyzing the main studies published in recent years.

Ventilatory neural drive in chronically hypercapnic patients with COPD: effects of sleep and nocturnal noninvasive ventilation

Sleep brings major challenges for the control of ventilation in humans, particularly the regulation of arterial carbon dioxide pressure (P _aCO2 ). In patients with COPD, chronic hypercapnia is associated with increased mortality. Therefore, nocturnal high-level noninvasive positive-pressure ventilation (NIV) is recommended with the intention to reduce P _aCO2 down to normocapnia. However, the long-term physiological consequences of P _aCO2 "correction" on the mechanics of breathing, gas exchange efficiency and resulting symptoms (i.e. dyspnoea) remain poorly understood. Investigating the influence of sleep on the neural drive to breathe and its translation to the mechanical act of breathing is of foremost relevance to create a solid rationale for the use of nocturnal NIV. In this review, we critically discuss the mechanisms by which sleep influences ventilatory neural drive and mechanical consequences in healthy subjects and hypercapnic patients with advanced COPD. We then discuss the available literature on the effects of nocturnal NIV on ventilatory neural drive and respiratory mechanics, highlighting open avenues for further investigation.

Home Non-Invasive Positive Pressure Ventilation in Chronic Obstructive Pulmonary Disease: Why, Who, and How?

Advanced chronic obstructive pulmonary disease (COPD) might result in chronic hypercapnic ventilatory failure. Similar to neuromuscular and restrictive chest wall diseases, long-term non-invasive positive pressure ventilation (NPPV) is increasingly used in chronic hypercapnic COPD. This review describes the methods, patient selection, ventilatory strategies, and therapeutic effects of long-term Home-NPPV based on randomized controlled clinical trials published since 1985 in English language retrieved from the databases PubMed and Scopus. Long-term NPPV is feasible and effective in stable, non-exacerbated COPD patients with daytime hypercapnia with arterial pressure of carbon dioxide (PaCO2) levels ≥50 mm Hg (6.6 kPa), if the applied ventilatory pressures and application times improve baseline hypercapnia by at least 20%. Patients who survived an acute hypercapnic exacerbation might benefit from long-term NPPV if hypercapnia persists 2-4 weeks after resolution of the exacerbation. Pressure-controlled ventilation or pressure-support ventilation with adequate minimum backup breathing frequencies, in combination with nasal masks or oronasal masks have been successfully used in all larger clinical trials. Ventilatory strategies with mean inspiratory pressures of up to 28 cm H2O are well-tolerated by patients, but limitations exist in patients with impaired cardiac performance. Home-NPPV with a PaCO2-reductive approach might be considered as an additional treatment option in patients with stable chronic hypercapnic COPD.

Physiological effects of high-intensity versus low-intensity noninvasive positive pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease: a randomised controlled trial

Background

High-intensity noninvasive positive pressure ventilation (NPPV) is a novel ventilatory approach to maximally decreasing elevated arterial carbon dioxide tension (PaCO₂) toward normocapnia with stepwise up-titration of pressure support. We tested whether high-intensity NPPV is more effective than low-intensity NPPV at decreasing PaCO₂, reducing inspiratory effort, alleviating dyspnoea, improving consciousness, and improving NPPV tolerance in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

In this physiological, randomised controlled trial, we assigned 24 AECOPD patients to undergo either high-intensity NPPV (n = 12) or low-intensity NPPV (n = 12). The primary outcome was PaCO₂ 24 h after randomisation. Secondary outcomes included gas exchange other than PaCO₂ 24 h after randomisation, inspiratory effort, dyspnoea, consciousness, NPPV tolerance, patient–ventilator asynchrony, cardiac function, ventilator-induced lung injury (VILI), and NPPV-related adverse events.

Results

Inspiratory positive airway pressure 24 h after randomisation was significantly higher (28.0 [26.0–28.0] vs. 15.5 [15.0–17.5] cmH₂O; p = 0.000) and NPPV duration within the first 24 h was significantly longer (21.8 ± 2.1 vs. 15.3 ± 4.7 h; p = 0.001) in the high-intensity NPPV group. PaCO₂ 24 h after randomisation decreased to 54.0 ± 11.6 mmHg in the high-intensity NPPV group but only decreased to 67.4 ± 10.6 mmHg in the low-intensity NPPV group (p = 0.008). Inspiratory oesophageal pressure swing, oesophageal pressure–time product (PTPes)/breath, PTPes/min, and PTPes/L were significantly lower in the high-intensity group. Accessory muscle use and dyspnoea score 24 h after randomisation were also significantly lower in that group. No significant between-groups differences were observed in consciousness, NPPV tolerance, patient–ventilator asynchrony, cardiac function, VILI, or NPPV-related adverse events.

Conclusions

High-intensity NPPV is more effective than low-intensity NPPV at decreasing elevated PaCO₂, reducing inspiratory effort, and alleviating dyspnoea in AECOPD patients.

Trial registration: ClinicalTrials.gov (NCT04044625; registered 5 August 2019).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01018-4.

Chronic hypercapnic respiratory failure and non-invasive ventilation in people with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) should no longer be seen as a condition for which little can be done. Novel pharmacotherapeutic interventions, surgical and procedural advances, and respiratory assist devices have provided numerous ways to help patients with COPD and treatable traits. For nearly 30 years, non-invasive ventilation, the application of positive pressure through a mask interface placed outside of the airway, has been the cornerstone for treatment of acute hypercapnic respiratory failure due to COPD exacerbation. Clinical trials indicate that this intervention could benefit patients with COPD and chronic hypercapnic respiratory failure in a stable state. This narrative review aims to provide the necessary background for internists to consider this therapeutic option for their COPD patients. We discuss the mechanism of action and implementation, and provide a glimpse into the future of this promising intervention.

Nasal versus oronasal masks for home non-invasive ventilation in patients with chronic hypercapnia: a systematic review and individual participant data meta-analysis

BACKGROUND

The optimal interface for the delivery of home non-invasive ventilation (NIV) to treat chronic respiratory failure has not yet been determined. The aim of this individual participant data (IPD) meta-analysis was to compare the effect of nasal and oronasal masks on treatment efficacy and adherence in patients with COPD and obesity hypoventilation syndrome (OHS).

METHODS

We searched Medline and Cochrane Central Register of Controlled Trials for prospective randomised controlled trials (RCTs) of at least 1 month's duration, published between January 1994 and April 2019, that assessed NIV efficacy in patients with OHS and COPD. The main outcomes were diurnal PaCO₂, PaO₂ and NIV adherence (PROSPERO CRD42019132398).

FINDINGS

Of 1576 articles identified, 34 RCTs met the inclusion criteria and IPD were obtained for 18. Ten RCTs were excluded because only one type of mask was used, or mask data were missing. Data from 8 RCTs, including 290 IPD, underwent meta-analysis. Oronasal masks were used in 86% of cases. There were no differences between oronasal and nasal masks for PaCO₂ (0.61 mm Hg (95% CI -2.15 to 3.38); p=0.68), PaO₂ (-0.00 mm Hg (95% CI -4.59 to 4.58); p=1) or NIV adherence (0·29 hour/day (95% CI -0.74 to 1.32); p=0.58). There was no interaction between the underlying pathology and the effect of mask type on any outcome.

INTERPRETATION

Oronasal masks are the most used interface for the delivery of home NIV in patients with OHS and COPD; however, there is no difference in the efficacy or tolerance of oronasal or nasal masks.

Management of Chronic Respiratory Failure in Chronic Obstructive Pulmonary Disease: High-Intensity and Low-Intensity Ventilation

A significant body of literature supports the benefit of noninvasive ventilation (NIV) for acute hypercapnia in the setting of exacerbations of chronic obstructive pulmonary disease (COPD). In those with severe COPD with chronic hypercapnic respiratory failure, however, the role of NIV has been more controversial. This article reviews the physiologic basis for considering NIV in patients with COPD, summarizes existing evidence supporting the role of NIV in COPD, highlights the patient population and ventilatory approach most likely to offer benefit, and suggests a potential clinical pathway for managing patients.

Long-Term Mechanical Ventilation: Recommendations of the Swiss Society of Pulmonology

Long-term mechanical ventilation is a well-established treatment for chronic hypercapnic respiratory failure (CHRF). It is aimed at improving CHRF-related symptoms, health-related quality of life, survival, and decreasing hospital admissions. In Switzerland, long-term mechanical ventilation has been increasingly used since the 1980s in hospital and home care settings. Over the years, its application has considerably expanded with accumulating evidence of beneficial effects in a broad range of conditions associated with CHRF. Most frequent indications for long-term mechanical ventilation are chronic obstructive pulmonary disease, obesity hypoventilation syndrome, neuromuscular and chest wall diseases. In the current consensus document, the Special Interest Group of the Swiss Society of Pulmonology reviews the most recent scientific literature on long-term mechanical ventilation and provides recommendations adapted to the particular setting of the Swiss healthcare system with a focus on the practice of non-invasive and invasive home ventilation in adults.

Sleep disordered breathing and chronic obstructive pulmonary disease: a narrative review on classification, pathophysiology and clinical outcomes

Chronic obstructive pulmonary disease (COPD) causes load-capacity-drive imbalance in both wakefulness and sleep, principally driven by expiratory flow limitation and hyperinflation. Sleep imposes additional burdens to the respiratory muscle pump, driven by changes in respiratory muscle tone, neural respiratory drive and consequences of the supine position. COPD patients are therefore at higher risk of decompensation during sleep, which may manifest as altered sleep architecture, isolated nocturnal desaturation, sleep hypoventilation and restless legs. Each form of sleep disordered breathing in COPD is associated with adverse clinical and patient-reported outcomes, including increased risk of exacerbations, hospitalisation, cardiovascular events, reduced survival and poorer quality of life. COPD-obstructive sleep apnoea (OSA) overlap syndrome represents a distinct clinical diagnosis, in which clinical outcomes are significantly worse than in either disease alone, including increased mortality, risk of cardiovascular events, hospitalisation and exacerbation frequency. Sleep disordered breathing is under-recognised by COPD patients and their clinicians, however early diagnosis and management is crucial to reduce the risk of adverse clinical outcomes. In this narrative review, we describe the pathophysiology of COPD and physiological changes that occur during sleep, manifestations and diagnosis of sleep disordered breathing in COPD and associated clinical outcomes.

Long-Term Noninvasive Ventilation in Chronic Stable Hypercapnic Chronic Obstructive Pulmonary Disease. An Official American Thoracic Society Clinical Practice Guideline

Background: Noninvasive ventilation (NIV) is used for patients with chronic obstructive pulmonary disease (COPD) and chronic hypercapnia. However, evidence for clinical efficacy and optimal management of therapy is limited.

Target Audience: Patients with COPD, clinicians who care for them, and policy makers.

Methods: We summarized evidence addressing five PICO (patients, intervention, comparator, and outcome) questions. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach was used to evaluate the certainty in evidence and generate actionable recommendations. Recommendations were formulated by a panel of pulmonary and sleep physicians, respiratory therapists, and methodologists using the Evidence-to-Decision framework.

Recommendations:1) We suggest the use of nocturnal NIV in addition to usual care for patients with chronic stable hypercapnic COPD (conditional recommendation, moderate certainty); 2) we suggest that patients with chronic stable hypercapnic COPD undergo screening for obstructive sleep apnea before initiation of long-term NIV (conditional recommendation, very low certainty); 3) we suggest not initiating long-term NIV during an admission for acute-on-chronic hypercapnic respiratory failure, favoring instead reassessment for NIV at 2–4 weeks after resolution (conditional recommendation, low certainty); 4) we suggest not using an in-laboratory overnight polysomnogram to titrate NIV in patients with chronic stable hypercapnic COPD who are initiating NIV (conditional recommendation, very low certainty); and 5) we suggest NIV with targeted normalization of Pa_CO2 in patients with hypercapnic COPD on long-term NIV (conditional recommendation, low certainty).

Conclusions: This expert panel provides evidence-based recommendations addressing the use of NIV in patients with COPD and chronic stable hypercapnic respiratory failure.

Extubating to Noninvasive Ventilation: Noninvasive Ventilation from Intensive Care Unit to Home

Weaning to noninvasive ventilation in intensive care unit and bridging the patients to home with respiratory support is evolving as the technology of noninvasive ventilation is improving. In patients with chronic obstructive pulmonary disease exacerbation, timing of initiation of noninvasive ventilation is the key, as persistently hypercapnic patients show benefits. High-intensity pressure support seems to do better in comparison to low-intensity pressure support. In patients with obesity and hypercapnia, obesity hypoventilation cannot be ruled out especially in an inpatient setting, and it is crucial that these patients are discharged with noninvasive ventilation.

Noninvasive Ventilator Devices and Modes

Noninvasive ventilation has become an increasingly common treatment strategy for patients with diverse conditions involving chronic respiratory failure. An intimate understanding of various advanced respiratory devices and modes is essential in the management of these patients. Pressure-limited modes of ventilation are more commonly used than volume modes for noninvasive ventilation owing to enhanced patient comfort and synchrony with the ventilator, as well as improved leak compensation. Common pressure modes include spontaneous/timed and pressure control, with volume-assured pressure support being an additive feature available on certain devices. Evidence guiding the optimal mode of ventilation for specific diseases is limited.

Home mechanical ventilation: quality of life patterns after six months of treatment

Background

It has been shown that home mechanical ventilation improves quality of life, but it has not been widely studied which particular patient groups benefit the most from starting this type of therapy. The purpose of this prospective observational study was to evaluate quality of life change patterns 6 months after initiation of home mechanical ventilation in patients suffering from chronic respiratory failure using patient reported outcomes.

Methods

We enrolled 74 chronic respiratory failure patients starting invasive or noninvasive home mechanical ventilation through the Semmelweis University Home Mechanical Ventilation Program. Quality of life was evaluated at baseline and at 6 months after initiation of home mechanical ventilation using the Severe Respiratory Insufficiency Questionnaire.

Results

Overall quality of life showed 10.5% improvement 6 months after initiation of home mechanical ventilation (p < 0.001). The greatest improvement was observed in Respiratory complaint (20.4%, p = 0.015), Sleep and attendant symptoms (19.3%, p < 0.001), and Anxiety related subscales (14.4%, p < 0.001). Interface (invasive versus noninvasive ventilation) was not associated with improvement in quality of life (p = 0.660). Severely impaired patients showed the greatest improvement (CC = -0.328, p < 0.001). Initial diagnosis contributed to the observed change (p = 0.025), with chronic obstructive pulmonary disease and obesity hypoventilation syndrome patients showing the greatest improvement, while amyotrophic lateral sclerosis patients showed no improvement in quality of life. We found that patients who were started on long term ventilation in an acute setting, required oxygen supplementation and had low baseline quality of life, showed the most improvement during the six-month study period.

Conclusions

Our study highlights the profound effect of home mechanical ventilation on quality of life in chronic respiratory failure patients that is indifferent of ventilation interface but is dependent on initial diagnosis and some baseline characteristics, like acute initiation, oxygen supplementation need and baseline quality of life.

Trial registration

This study was approved by and registered at the ethics committee of Semmelweis University (SE TUKEB 251/2017; 20th of December, 2017).

European Respiratory Society guidelines on long-term home non-invasive ventilation for management of COPD

Background

While the role of acute non-invasive ventilation (NIV) has been shown to improve outcome in acute life-threatening hypercapnic respiratory failure in COPD, the evidence of clinical efficacy of long-term home NIV (LTH-NIV) for management of COPD is less. This document provides evidence-based recommendations for the clinical application of LTH-NIV in chronic hypercapnic COPD patients.

Materials and methods

The European Respiratory Society task force committee was composed of clinicians, methodologists and experts in the field of LTH-NIV. The committee developed recommendations based on the GRADE (Grading, Recommendation, Assessment, Development and Evaluation) methodology. The GRADE Evidence to Decision framework was used to formulate recommendations. A number of topics were addressed under a narrative format which provides a useful context for clinicians and patients.

Results

The task force committee delivered conditional recommendations for four actionable PICO (target population-intervention-comparator-outcome) questions, 1) suggesting for the use of LTH-NIV in stable hypercapnic COPD; 2) suggesting for the use of LTH-NIV in COPD patients following a COPD exacerbation requiring acute NIV 3) suggesting for the use of NIV settings targeting a reduction in carbon dioxide and 4) suggesting for using fixed pressure support as first choice ventilator mode.

Conclusions

Managing hypercapnia may be an important intervention for improving the health outcome of COPD patients with chronic respiratory failure. The task force conditionally supports the application of LTH-NIV to improve health outcome by targeting a reduction in carbon dioxide in COPD patients with persistent hypercapnic respiratory failure. These recommendations should be applied in clinical practice by practitioners that routinely care for chronic hypercapnic COPD patients.

More than Heart Failure: Central Sleep Apnea and Sleep-Related Hypoventilation

Central sleep apnea (CSA) comprises a variety of breathing patterns and clinical entities. They can be classified into 2 categories based on the partial pressure of carbon dioxide in the arterial blood. Nonhypercapnic CSA is usually characterized by a periodic breathing pattern, while hypercapnic CSA is based on hypoventilation. The latter CSA form is associated with central nervous, neuromuscular, and rib cage disorders as well as obesity and certain medication or substance intake. In contrast, nonhypercapnic CSA is typically accompanied by an overshoot of the ventilation and often associated with heart failure, cerebrovascular diseases, and stay in high altitude. CSA and hypoventilation syndromes are often considered separately, but pathophysiological aspects frequently overlap. An integrative approach helps to recognize underlying pathophysiological mechanisms and to choose adequate therapeutic strategies. Research in the last decades improved our insights; nevertheless, diagnostic tools are not always appropriately chosen to perform comprehensive sleep studies. This supports misinterpretation and misclassification of sleep disordered breathing. The purpose of this article is to highlight unresolved problems, raise awareness for different pathophysiological components and to discuss the evidence for targeted therapeutic strategies.

Spontaneous-timed versus controlled noninvasive ventilation in chronic hypercapnia - a crossover trial

Background: There is an ongoing debate about optimal ventilator modes and settings during noninvasive ventilation (NIV). Objectives: To compare the effect of spontaneous-timed (ST) and controlled NIV on carbon dioxide reduction in patients suffering from chronic hypercapnia. Methods: Night and daytime blood gas analysis, lung function tests and 6 minute walking distance tests (6MWD) were done before and after every 6-week treatment. Results: This randomized prospective crossover trial included 42 patients. Pooled data analysis showed a decrease of nocturnal CO₂ from 54.8±5.9 mmHg to 41.6±5.5 mmHg during ST ventilation (p<0.01) and from 56.2±7.5 mmHg to 42.7±5.4 mmHg during controlled NIV (p<0.01) with no difference between treatment forms (p=0.30). Daytime CO₂ levels decreased from 49.3±5.5 mmHg to 45.6±4.5 mmHg when spontaneous timed ventilation was applied (p<0.01) and from 52.2±6.8 mmHg to 44.9±21114.4 mmHg in case of controlled ventilation (p<0.01) The amount of CO₂ reduction was 3.8±5.6 mmHg after ST mode and 7.3±6.8 mmHg controlled ventilation (p<0.05). Nocturnal ventilator use was 5.7±2.1 and 6.7±2.3 hours for ST and controlled ventilation respectively (p=0.02). There was no effect on walking distance and lung function. Conclusion: Controlled NIV showed improved compliance compared to ST ventilation. We observed similar CO₂ reductions during nocturnal ventilation, however controlled ventilation achieved a higher reduction of daytime CO₂ levels.

High-intensity non-invasive ventilation in stable hypercapnic COPD: Evidence of efficacy and practical advice

Patients with end-stage chronic obstructive pulmonary disease (COPD) frequently develop chronic hypercapnic respiratory failure (CHRF), with disabling symptoms and poor survival. The use of long-term nocturnal non-invasive ventilation (NIV) to treat CHRF in COPD has long been subject of debate due to conflicting evidence. However, since the introduction of high-intensity NIV (HI-NIV) in COPD, physiological and clinical benefits have been shown. HI-NIV refers to specific ventilator settings used for NIV aimed at achieving normocapnia or the lowest partial arterial carbon dioxide pressure (PaCO₂ ) values as possible. This review will provide an overview of existing evidence of the efficacy of HI-NIV stable COPD patients with CHRF. Secondly, we will discuss hypotheses underlying NIV benefit in stable hypercapnic COPD, providing insight into better patient selection and hopefully more individually titrated HI-NIV. Finally, we will provide practical advice on how to initiate and follow-up patients on HI-NIV, with special emphasis on monitoring that should be available during the initiation and follow-up of HI-NIV, and will discuss more extended monitoring techniques that could improve HI-NIV treatment in the future.

Health-related quality of life measurement in patients with chronic respiratory failure

The improvement of health-related quality of life (HRQL) is an important goal in managing patients with chronic respiratory failure (CRF) receiving long-term oxygen therapy (LTOT) and/or domiciliary noninvasive ventilation (NIV). Two condition-specific HRQL questionnaires have been developed to specifically assess these patients: the Maugeri Respiratory Failure Questionnaire (MRF) and the Severe Respiratory Insufficiency Questionnaire (SRI). The MRF is more advantageous in its ease of completion; conversely, the SRI measures diversified health impairments more multi-dimensionally and discriminatively with greater balance, especially in patients receiving NIV. The SRI is available in many different languages as a result of back-translation and validation processes, and is widely validated for various disorders such as chronic obstructive pulmonary disease, restrictive thoracic disorders, neuromuscular disorders, and obesity hypoventilation syndrome, among others. Dyspnea and psychological status were the main determinants for both questionnaires, while the MRF tended to place more emphasis on activity limitations than SRI. In comparison to existing generic questionnaires such as the Medical Outcomes Study 36-item short form (SF-36) and disease-specific questionnaires such as the St. George's Respiratory Questionnaire (SGRQ) and the Chronic Respiratory Disease Questionnaire (CRQ), both the MRF and the SRI have been shown to be valid and reliable, and have better discriminatory, evaluative, and predictive features than other questionnaires. Thus, in assessing the HRQL of patients with CRF using LTOT and/or NIV, we might consider avoiding the use of the SF-36 or even the SGRQ or CRQ alone and consider using the CRF-specific SRI and MRF in addition to existing generic and/or disease-specific questionnaires.

High-pressure versus low-pressure home non-invasive positive pressure ventilation with built-in software in patients with stable hypercapnic COPD: a pilot study

High-pressure non-invasive positive pressure ventilation (NPPV) is a new strategy targeted at maximally reducing arterial carbon dioxide. However, high inspiratory positive airway pressure (IPAP) might cause respiratory adverse events likely to diminish the benefit of NPPV. In the setting of ventilatory support, monitoring NPPV efficacy and resolving problems promptly are critical. This study assessed the treatment effect of high and low-pressure NPPV in chronic hypercapnic COPD using home ventilator with built-in software. In this pilot study, we investigated 34 patients using NPPV for 3 months. 13 patients used high-pressure ventilation and 21 patients used low-pressure ventilation. The primary outcome was daytime partial pressure of arterial blood carbon dioxide (P_aCO₂). There were no between-group differences in daytime P_aCO₂ and FEV₁, but a trend favouring high-pressure NPPV was observed. Significant between-group differences were found in the transition dyspnoea index (TDI) (high-pressure, 1.69 ± 1.75, versus low-pressure, -0.04 ± 2.71, p = 0.044). No differences were found in usage time, leakage, health-related quality of life, spirometry, or 6-minute walk test. High-pressure NPPV with built-in software monitoring in patients with chronic hypercapnic COPD is associated with improvement in TDI scores and a positive trend in favour of high-pressure NPPV for improving P_aCO₂ is observed.

Effect of Home Noninvasive Ventilation With Oxygen Therapy vs Oxygen Therapy Alone on Hospital Readmission or Death After an Acute COPD Exacerbation: A Randomized Clinical Trial

IMPORTANCE

Outcomes after exacerbations of chronic obstructive pulmonary disease (COPD) requiring acute noninvasive ventilation (NIV) are poor and there are few treatments to prevent hospital readmission and death.

OBJECTIVE

To investigate the effect of home NIV plus oxygen on time to readmission or death in patients with persistent hypercapnia after an acute COPD exacerbation.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial of patients with persistent hypercapnia (Paco2 >53 mm Hg) 2 weeks to 4 weeks after resolution of respiratory acidemia, who were recruited from 13 UK centers between 2010 and 2015. Exclusion criteria included obesity (body mass index [BMI] >35), obstructive sleep apnea syndrome, or other causes of respiratory failure. Of 2021 patients screened, 124 were eligible.

INTERVENTIONS

There were 59 patients randomized to home oxygen alone (median oxygen flow rate, 1.0 L/min [interquartile range {IQR}, 0.5-2.0 L/min]) and 57 patients to home oxygen plus home NIV (median oxygen flow rate, 1.0 L/min [IQR, 0.5-1.5 L/min]). The median home ventilator settings were an inspiratory positive airway pressure of 24 (IQR, 22-26) cm H2O, an expiratory positive airway pressure of 4 (IQR, 4-5) cm H2O, and a backup rate of 14 (IQR, 14-16) breaths/minute.

MAIN OUTCOMES AND MEASURES

Time to readmission or death within 12 months adjusted for the number of previous COPD admissions, previous use of long-term oxygen, age, and BMI.

RESULTS

A total of 116 patients (mean [SD] age of 67 [10] years, 53% female, mean BMI of 21.6 [IQR, 18.2-26.1], mean [SD] forced expiratory volume in the first second of expiration of 0.6 L [0.2 L], and mean [SD] Paco2 while breathing room air of 59 [7] mm Hg) were randomized. Sixty-four patients (28 in home oxygen alone and 36 in home oxygen plus home NIV) completed the 12-month study period. The median time to readmission or death was 4.3 months (IQR, 1.3-13.8 months) in the home oxygen plus home NIV group vs 1.4 months (IQR, 0.5-3.9 months) in the home oxygen alone group, adjusted hazard ratio of 0.49 (95% CI, 0.31-0.77; P = .002). The 12-month risk of readmission or death was 63.4% in the home oxygen plus home NIV group vs 80.4% in the home oxygen alone group, absolute risk reduction of 17.0% (95% CI, 0.1%-34.0%). At 12 months, 16 patients had died in the home oxygen plus home NIV group vs 19 in the home oxygen alone group.

CONCLUSIONS AND RELEVANCE

Among patients with persistent hypercapnia following an acute exacerbation of COPD, adding home noninvasive ventilation to home oxygen therapy prolonged the time to readmission or death within 12 months.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00990132.

Non-invasive ventilation with intelligent volume-assured pressure support versus pressure-controlled ventilation: effects on the respiratory event rate and sleep quality in COPD with chronic hypercapnia

BACKGROUND

COPD patients who develop chronic hypercapnic respiratory failure have a poor prognosis. Treatment of choice, especially the best form of ventilation, is not well known.

OBJECTIVES

This study compared the effects of pressure-controlled (spontaneous timed [ST]) non-invasive ventilation (NIV) and NIV with intelligent volume-assured pressure support (IVAPS) in chronic hypercapnic COPD patients regarding the effects on alveolar ventilation, adverse patient/ventilator interactions and sleep quality.

METHODS

This prospective, single-center, crossover study randomized patients to one night of NIV using ST then one night with the IVAPS function activated, or vice versa. Patients were monitored using polysomnography (PSG) and transcutaneous carbon dioxide pressure (PtcCO2) measurement. Patients rated their subjective experience (total score, 0-45; lower scores indicate better acceptability).

RESULTS

Fourteen patients were included (4 females, age 59.4±8.9 years). The total number of respiratory events was low, and similar under pressure-controlled (5.4±6.7) and IVAPS (8.3±10.2) conditions (P=0.064). There were also no clinically relevant differences in PtcCO2 between pressure-controlled and IVAPS NIV (52.9±6.2 versus 49.1±6.4 mmHg). Respiratory rate was lower under IVAPS overall; between-group differences reached statistical significance during wakefulness and non-rapid eye movement sleep. Ventilation pressures were 2.6 cmH2O higher under IVAPS versus pressure-controlled ventilation, resulting in a 20.1 mL increase in breathing volume. Sleep efficiency was slightly higher under pressure-controlled ventilation versus IVAPS. Respiratory arousals were uncommon (24.4/h [pressure-controlled] versus 25.4/h [IVAPS]). Overall patient assessment scores were similar, although there was a trend toward less discomfort during IVAPS.

CONCLUSION

Our results show that IVAPS NIV allows application of higher nocturnal ventilation pressures versus ST without affecting sleep quality or inducing ventilation- associated events.

Respiratory muscle activity and patient-ventilator asynchrony during different settings of noninvasive ventilation in stable hypercapnic COPD: does high inspiratory pressure lead to respiratory muscle unloading?

Introduction

High-intensity noninvasive ventilation (NIV) has been shown to improve outcomes in stable chronic obstructive pulmonary disease patients. However, there is insufficient knowledge about whether with this more controlled ventilatory mode optimal respiratory muscle unloading is provided without an increase in patient–ventilator asynchrony (PVA).

Patients and methods

Ten chronic obstructive pulmonary disease patients on home mechanical ventilation were included. Four different ventilatory settings were investigated in each patient in random order, each for 15 min, varying the inspiratory positive airway pressure and backup breathing frequency. With surface electromyography (EMG), activities of the intercostal muscles, diaphragm, and scalene muscles were determined. Furthermore, pressure tracings were derived simultaneously in order to assess PVA.

Results

Compared to spontaneous breathing, the most pronounced decrease in EMG activity was achieved with the high-pressure settings. Adding a high breathing frequency did reduce EMG activity per breath, while the decrease in EMG activity over 1 min was comparable with the high-pressure, low-frequency setting. With high backup breathing frequencies less breaths were pressure supported (25% vs 97%). PVAs occurred more frequently with the low-frequency settings (P=0.017).

Conclusion

High-intensity NIV might provide optimal unloading of respiratory muscles, without undue increases in PVA.

The effect of domiciliary noninvasive ventilation on clinical outcomes in stable and recently hospitalized patients with COPD: a systematic review and meta-analysis

Introduction

Noninvasive ventilation (NIV) improves survival among patients with hypercapnic respiratory failure in hospital, but evidence for its use in domiciliary settings is limited. A patient’s underlying risk of having an exacerbation may affect any potential benefit that can be gained from domiciliary NIV. This is the first comprehensive systematic review to stratify patients based on a proxy for exacerbation risk: patients in a stable state and those immediately post-exacerbation hospitalization.

Methods

A systematic review of nonrandomized and randomized controlled trials (RCTs) was undertaken in order to compare the relative effectiveness of different types of domiciliary NIV and usual care on hospital admissions, mortality, and health-related quality of life. Standard systematic review methods were used for identifying studies (until September 2014), quality appraisal, and synthesis. Data were presented in forest plots and pooled where appropriate using random-effects meta-analysis.

Results

Thirty-one studies were included. For stable patients, there was no evidence of a survival benefit from NIV (relative risk [RR] 0.88 [0.55, 1.43], I²=60.4%, n=7 RCTs), but there was a possible trend toward fewer hospitalizations (weighted mean difference −0.46 [−1.02, 0.09], I²=59.2%, n=5 RCTs) and improved health-related quality of life. For posthospital patients, survival benefit could not be demonstrated within the three RCTs (RR 0.89 [0.53, 1.49], I²=25.1%), although there was evidence of benefit from four non-RCTs (RR 0.45 [0.32, 0.65], I²=0%). Effects on hospitalizations were inconsistent. Post hoc analyses suggested that NIV-related improvements in hypercapnia were associated with reduced hospital admissions across both populations. Little data were available comparing different types of NIV.

Conclusion

The effectiveness of domiciliary NIV remains uncertain; however, some patients may benefit. Further research is required to identify these patients and to explore the relevance of improvements in hypercapnia in influencing clinical outcomes. Optimum time points for commencing domiciliary NIV and equipment settings need to be established.

The cost-effectiveness of domiciliary non-invasive ventilation in patients with end-stage chronic obstructive pulmonary disease: a systematic review and economic evaluation

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic progressive lung disease characterised by non-reversible airflow obstruction. Exacerbations are a key cause of morbidity and mortality and place a considerable burden on health-care systems. While there is evidence that patients benefit from non-invasive ventilation (NIV) in hospital during an acute exacerbation, evidence supporting home use for more stable COPD patients is limited. In the U.K., domiciliary NIV is considered on health economic grounds in patients after three hospital admissions for acute hypercapnic respiratory failure.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of domiciliary NIV by systematic review and economic evaluation.

DATA SOURCES

Bibliographic databases, conference proceedings and ongoing trial registries up to September 2014.

METHODS

Standard systematic review methods were used for identifying relevant clinical effectiveness and cost-effectiveness studies assessing NIV compared with usual care or comparing different types of NIV. Risk of bias was assessed using Cochrane guidelines and relevant economic checklists. Results for primary effectiveness outcomes (mortality, hospitalisations, exacerbations and quality of life) were presented, where possible, in forest plots. A speculative Markov decision model was developed to compare the cost-effectiveness of domiciliary NIV with usual care from a UK perspective for post-hospital and more stable populations separately.

RESULTS

Thirty-one controlled effectiveness studies were identified, which report a variety of outcomes. For stable patients, a modest volume of evidence found no benefit from domiciliary NIV for survival and some non-significant beneficial trends for hospitalisations and quality of life. For post-hospital patients, no benefit from NIV could be shown in terms of survival (from randomised controlled trials) and findings for hospital admissions were inconsistent and based on limited evidence. No conclusions could be drawn regarding potential benefit from different types of NIV. No cost-effectiveness studies of domiciliary NIV were identified. Economic modelling suggested that NIV may be cost-effective in a stable population at a threshold of £30,000 per quality-adjusted life-year (QALY) gained (incremental cost-effectiveness ratio £28,162), but this is associated with uncertainty. In the case of the post-hospital population, results for three separate base cases ranged from usual care dominating to NIV being cost-effective, with an incremental cost-effectiveness ratio of less than £10,000 per QALY gained. All estimates were sensitive to effectiveness estimates, length of benefit from NIV (currently unknown) and some costs. Modelling suggested that reductions in the rate of hospital admissions per patient per year of 24% and 15% in the stable and post-hospital populations, respectively, are required for NIV to be cost-effective.

LIMITATIONS

Evidence on key clinical outcomes remains limited, particularly quality-of-life and long-term (> 2 years) effects. Economic modelling should be viewed as speculative because of uncertainty around effect estimates, baseline risks, length of benefit of NIV and limited quality-of-life/utility data.

CONCLUSIONS

The cost-effectiveness of domiciliary NIV remains uncertain and the findings in this report are sensitive to emergent data. Further evidence is required to identify patients most likely to benefit from domiciliary NIV and to establish optimum time points for starting NIV and equipment settings.

FUTURE WORK RECOMMENDATIONS

The results from this report will need to be re-examined in the light of any new trial results, particularly in terms of reducing the uncertainty in the economic model. Any new randomised controlled trials should consider including a sham non-invasive ventilation arm and/or a higher- and lower-pressure arm. Individual participant data analyses may help to determine whether or not there are any patient characteristics or equipment settings that are predictive of a benefit of NIV and to establish optimum time points for starting (and potentially discounting) NIV.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012003286.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Update: Non-Invasive Positive Pressure Ventilation in Chronic Respiratory Failure Due to COPD

Long-term non-invasive positive pressure ventilation (NPPV) has widely been accepted to treat chronic hypercapnic respiratory failure arising from different etiologies. Although the survival benefits provided by long-term NPPV in individuals with restrictive thoracic disorders or stable, slowly-progressing neuromuscular disorders are overwhelming, the benefits provided by long-term NPPV in patients with chronic obstructive pulmonary disease (COPD) remain under question, due to a lack of convincing evidence in the literature. In addition, long-term NPPV reportedly failed in the classic trials to improve important physiological parameters such as arterial blood gases, which might serve as an explanation as to why long-term NPPV has not been shown to substantially impact on survival. However, high intensity NPPV (HI-NPPV) using controlled NPPV with the highest possible inspiratory pressures tolerated by the patient has recently been described as a new and promising approach that is well-tolerated and is also capable of improving important physiological parameters such as arterial blood gases and lung function. This clearly contrasts with the conventional approach of low-intensity NPPV (LI-NPPV) that uses considerably lower inspiratory pressures with assisted forms of NPPV. Importantly, HI-NPPV was very recently shown to be superior to LI-NPPV in terms of improved overnight blood gases, and was also better tolerated than LI-NPPV. Furthermore, HI-NPPV, but not LI-NPPV, improved dyspnea, lung function and disease-specific aspects of health-related quality of life. A recent study showed that long-term treatment with NPPV with increased ventilatory pressures that reduced hypercapnia was associated with significant and sustained improvements in overall mortality. Thus, long-term NPPV seems to offer important benefits in this patient group, but the treatment success might be dependent on effective ventilatory strategies.

Chronic hypoventilation syndromes and sleep-related hypoventilation

Chronic hypoventilation affects patients with disorders on any level of the respiratory system. The generation of respiratory impulses can be impaired in congenital disorders, such as central congenital alveolar hypoventilation, in alterations of the brain stem or complex diseases like obesity hypoventilation. The translation of the impulses via spinal cord and nerves to the respiratory muscles can be impaired in neurological diseases. Thoraco-skeletal or muscular diseases may inhibit the execution of the impulses. All hypoventilation disorders are characterized by a reduction of the minute ventilation with an increase of daytime hypercapnia. As sleep reduces minute ventilation substantially in healthy persons and much more pronounced in patients with underlying thoraco-pulmonary diseases, hypoventilation manifests firstly during sleep. Therefore, sleep related hypoventilation may be an early stage of chronic hypoventilation disorders. After treatment of any prevailing underlying disease, symptomatic therapy with non-invasive ventilation (NIV) is required. The adaptation of the treatment should be performed under close medical supervision. Pressure support algorithms have become most frequently used. The most recent devices automatically apply pressure support and vary inspiratory and expiratory pressures and breathing frequency in order to stabilize upper airways, normalize ventilation, achieve best synchronicity between patient and device and aim at optimizing patients' adherence.

Sleep disorders in chronic obstructive pulmonary disease: etiology, impact, and management

ABSTRACT

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality and may frequently be complicated by sleep disorders. Insomnia and obstructive sleep apnea are commonly encountered in patients with COPD. Nocturnal hypoxemia is also prevalent in COPD may occur despite adequate awake oxygenation and can be especially severe in rapid eye movement sleep. Additionally, several factors--some of them unique to COPD--can contribute to sleep-related hypoventilation. Recognition of hypoventilation can be vital as supplemental oxygen therapy itself can acutely worsen hypoventilation and lead to disastrous consequences. Finally, accruing data establish an association between restless leg syndrome and COPD--an association that may be driven by hypoxemia and/or hypercapnia. Comorbid sleep disorders portend worse sleep quality, diminished quality of life, and multifarious other adverse consequences. The awareness and knowledge regarding sleep comorbidities in COPD has continued to evolve over past many years. There are still several lacunae, however, in our understanding of the etiologies, impact, and therapies of sleep disorders, specifically in patients with COPD. This review summarizes the latest concepts in prevalence, pathogenesis, diagnosis, and management of diverse sleep disorders in COPD.

Noninvasive ventilation in acute respiratory failure

After the institution of positive-pressure ventilation, the use of noninvasive ventilation (NIV) through an interface substantially increased. The first technique was continuous positive airway pressure; but, after the introduction of pressure support ventilation at the end of the 20th century, this became the main modality. Both techniques, and some others that have been recently introduced and which integrate some technological innovations, have extensively demonstrated a faster improvement of acute respiratory failure in different patient populations, avoiding endotracheal intubation and facilitating the release of conventional invasive mechanical ventilation. In acute settings, NIV is currently the first-line treatment for moderate-to-severe chronic obstructive pulmonary disease exacerbation as well as for acute cardiogenic pulmonary edema and should be considered in immunocompromised patients with acute respiratory insufficiency, in difficult weaning, and in the prevention of postextubation failure. Alternatively, it can also be used in the postoperative period and in cases of pneumonia and asthma or as a palliative treatment. NIV is currently used in a wide range of acute settings, such as critical care and emergency departments, hospital wards, palliative or pediatric units, and in pre-hospital care. It is also used as a home care therapy in patients with chronic pulmonary or sleep disorders. The appropriate selection of patients and the adaptation to the technique are the keys to success. This review essentially analyzes the evidence of benefits of NIV in different populations with acute respiratory failure and describes the main modalities, new devices, and some practical aspects of the use of this technique.

Volume assured versus pressure preset non-invasive ventilation for compensated ventilatory failure in COPD

BACKGROUND

The addition of domiciliary non-invasive ventilation (NIV) to standard therapy in chronic obstructive pulmonary disease (COPD) patients with compensated ventilatory failure (CVF) is reported to have beneficial effects. Compliance with NIV is an important factor. Volume assured NIV (va-NIV) may improve compliance and ventilation during sleep by automatically titrating ventilatory pressures.

METHODS

A prospective single centre, randomised, parallel group trial comparing va-NIV and pressure preset NIV (pp-NIV) in COPD patients with CVF naïve to domiciliary NIV was performed (ISCRTN91892415). The primary outcomes were arterial blood gases, mean overnight oximetry (mSpO2) and compliance after three months. Secondary outcomes included pulmonary function, exercise capacity and health-related quality of life assessment.

RESULTS

Forty patients were randomised in a 1:1 ratio. The va-NIV median target minute ventilation was 8.4 L/min and pp-NIV median inspiratory pressure was 28 cmH2O. There were no significant differences between groups in primary or secondary outcomes after three months. Mean (SD) PaO2 8.7 (1.7) versus 7.9 (1.7) kPa (p = 0.19), PaCO2 6.7 (0.5) versus 7.3 (1.1) kPa (p = 0.1), mSpO2 89.7 (4.2) versus 89.8 (3.9) % (p = 0.95), compliance 5.0 (3.1) versus 4.7 (3.2) hours (p = 0.8) in va-NIV versus pp-NIV respectively. Patients allocated va-NIV spent fewer days in hospital initiating therapy 3.3 (1.6) versus 5.2 (2.8) (p = 0.02). Both groups showed significant improvements in PaCO2 and mSpO2 after three months treatment.

CONCLUSIONS

Domiciliary va-NIV and pp-NIV have similar effects on physiological outcomes in COPD patients with CVF and both are well tolerated.

Non-invasive ventilation in the treatment of sleep-related breathing disorders: A review and update

Non-invasive mechanical ventilation (NIV) was originally used in patients with acute respiratory compromises or exacerbations of chronic respiratory diseases as an alternative to intubation. Over the last thirty years NIV has been used during the night in patients with stable chronic lung diseases such as obstructive sleep apnea, the overlap syndrome (COPD and obstructive sleep apnea), neuromuscular disorders, obesity-hypoventilation syndrome and in other conditions such as sleep disorders associated with congestive heart failure. In this review we discuss the different types of NIV, the specific conditions in which they can be used as well as the indications, recommendations, and evidence supporting the efficacy of NIV.