Long-term controlled trial of nocturnal nasal positive pressure ventilation in patients with severe COPD

The Importance of Stabilizing PaCO2 during Long-term Non-invasive Ventilation in Subjects with COPD

OBJECTIVE

In subjects with chronic obstructive pulmonary disease (COPD), the effect of partial pressure of CO2 (PaCO2) alterations during long-term non-invasive ventilation (NIV) on continuance remains uncertain. We herein investigated the utility of PaCO2 stability during long-term NIV as a prognostic outcome.

METHODS

We retrospectively assessed data from 54 subjects with COPD who received long-term NIV. The annual alteration in PaCO2 during NIV was determined using a simple linear regression method for each subject who had at least two 6-month intervals of PaCO2 data. Annual alterations in PaCO2 during long-term NIV and probable confounders were examined, and long-term NIV discontinuation was the major outcome.

RESULTS

Data from 37 subjects who met the criteria were analyzed. PaCO2 during long-term NIV increased slightly in 19 subjects (group 1, <2 mm Hg/y), and increased greatly in 18 subjects (group 2, >2 mmHg/y). In the multivariate modality model, smaller annual alterations in PaCO2 (p=0.009) and lower PaCO2 6 months after the start of long-term NIV (6 m-PaCO2) (p=0.03) were associated with a significantly higher probability of continuing NIV. The 2- and 5-year probabilities of continuing NIV were 89% and 66% for group 1 and 78% and 32% for group 2, respectively.

CONCLUSION

A lower 6 m-PaCO2 and a lower annual alteration of PaCO2 during long-term NIV are significant predictive variables for patients with 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.

Non-invasive positive pressure ventilation for the treatment of severe stable chronic obstructive pulmonary disease: a prospective, multicentre, randomised, controlled clinical trial

BACKGROUND

Evidence is weak for the ability of long-term non-invasive positive pressure ventilation (NPPV) to improve survival in patients with stable hypercapnic chronic obstructive pulmonary disease (COPD). Previous prospective studies did not target a reduction in hypercapnia when adjusting ventilator settings. This study investigated the effect of long-term NPPV, targeted to markedly reduce hypercapnia, on survival in patients with advanced, stable hypercapnic COPD.

METHODS

This investigator-initiated, prospective, multicentre, randomised, controlled clinical trial enrolled patients with stable GOLD stage IV COPD and a partial carbon dioxide pressure (PaCO2) of 7 kPa (51.9 mm Hg) or higher and pH higher than 7.35. NPPV was targeted to reduce baseline PaCO2 by at least 20% or to achieve PaCO2 values lower than 6.5 kPa (48.1 mm Hg). Patients were randomly assigned (in a 1:1 ratio) via a computer-generated randomisation sequence with a block size of four, to continue optimised standard treatment (control group) or to receive additional NPPV for at least 12 months (intervention group). The primary outcome was 1-year all-cause mortality. Analysis was by intention to treat. The intervention was unblinded, but outcome assessment was blinded to treatment assignment. This study is registered with ClinicalTrials.gov, number NCT00710541.

FINDINGS

Patients were recruited from 36 respiratory units in Germany and Austria, starting on Oct 29, 2004, and terminated with a record of the vital status on July 31, 2011. 195 patients were randomly assigned to the NPPV group (n=102) or to the control group (n=93). All patients from the control group and the NPPV group were included in the primary analysis. 1-year mortality was 12% (12 of 102 patients) in the intervention group and 33% (31 of 93 patients) in the control group; hazard ratio 0.24 (95% CI 0.11-0.49; p=0.0004). 14 (14%) patients reported facial skin rash, which could be managed by changing the type of the mask. No other intervention-related adverse events were reported.

INTERPRETATION

The addition of long-term NPPV to standard treatment improves survival of patients with hypercapnic, stable COPD when NPPV is targeted to greatly reduce hypercapnia.

FUNDING

German Lung Foundation; ResMed, Germany; Tyco Healthcare, Germany; and Weinmann, Germany.

Long-term adherence with non-invasive ventilation improves prognosis in obese COPD patients

BACKGROUND AND OBJECTIVE

Long-term non-invasive ventilation (NIV) has become a widespread modality of treatment in chronic obstructive pulmonary disease (COPD) patients with chronic respiratory failure. However, benefits in terms of patient-related outcomes are still under debate. Both NIV adherence and heterogeneous responses in different COPD phenotypes may contribute to the difficulty of demonstrating NIV benefits. Our aim was to assess the impact of NIV adherence on the rate of hospitalization for acute exacerbation and death.

METHODS

This is a prospective multi-centre cohort study of COPD patients treated by long-term NIV. Comorbidities, anthropometrics, respiratory parameters were collected at inclusion in the study. Follow-up data included vital status, NIV adherence and hospitalizations. The influence of NIV adherence on prognosis was tested using an adjusted Cox model. Sensitivity analyses for obese and non-obese COPD subtypes were also conducted.

RESULTS

Two hundred thirteen patients (48% obese) were included with 45.5% died during 47.7 [interquartile range = 27.8; 73] months' follow-up. Survival was better in obese COPD than non-obese COPD. The use of NIV > 9 h/day was associated with an increased risk of death or hospitalization for acute exacerbation [HR = 1.6; 95CI: 1.1-2.4]. In obese COPD, this risk described a U-shaped curve from >1 to >9 h/day NIV usage with an improvement in prognosis when NIV adherence was > 5 h/day [HR = 0.5; 95CI: 0.2-0.9].

CONCLUSIONS

Adherence to NIV was associated with better prognosis only in obese COPD. NIV use > 9 h/day predicted poor outcomes.

Current opinions on non-invasive ventilation as a treatment for chronic obstructive pulmonary disease

PURPOSE OF REVIEW

This review examines the current reports, the evidence and the issues surrounding the use of non-invasive ventilation (NIV) for the treatment of chronic obstructive pulmonary disease (COPD) in both the acute and domiciliary setting.

RECENT FINDINGS

With the increasing use of NIV, more recent studies have focused on investigating the outcomes of our current practice. Although overall morbidity and mortality outcomes in the acute setting have improved, patients who initially stabilize but then deteriorate during an acute exacerbation of COPD have a poor prognosis. The focus must be on phenotyping this high-risk group to investigate other potential rescue treatments, including extracorporeal carbon dioxide removal. Indeed, phenotyping appears to favour the obese COPD patient, which may have a protective role in reducing the risk of NIV failure and recurrent hospital admissions. Randomized controlled trial evidence to support the use of NIV in a domiciliary setting as a treatment for COPD is awaited, and until the data from a number of ongoing clinical trials are available, the wide variation in global practice will continue. Increased understanding of patient ventilator asynchrony has improved domiciliary NIV set up, which is expected to enhance the tolerability of NIV, promoting patient adherence.

SUMMARY

NIV is the established standard of care to treat acute hypercapnic exacerbations of COPD postoptimal medical management. NIV as a long-term treatment for COPD remains controversial based on the evidence from the published randomized controlled trials. With increasing experience of NIV therapy, patient outcomes are improving; however, further work is still required to better characterize and target the patients who will most benefit from NIV.

Long-term home noninvasive mechanical ventilation increases systemic inflammatory response in chronic obstructive pulmonary disease: a prospective observational study

Background. Long-term home noninvasive mechanical ventilation (NIV) is beneficial in COPD but its impact on inflammation is unknown. We assessed the hypothesis that NIV modulates systemic and pulmonary inflammatory biomarkers in stable COPD. Methods. Among 610 patients referred for NIV, we shortlisted those undergoing NIV versus oxygen therapy alone, excluding subjects with comorbidities or non-COPD conditions. Sputum and blood samples were collected after 3 months of clinical stability and analyzed for levels of human neutrophil peptides (HNP), interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-alpha). Patients underwent a two-year follow-up. Unadjusted, propensity-matched, and pH-stratified analyses were performed. Results. Ninety-three patients were included (48 NIV, 45 oxygen), with analogous baseline features. Sputum analysis showed similar HNP, IL-6, IL-10, and TNF-alpha levels (P > 0.5). Conversely, NIV group exhibited higher HNP and IL-6 systemic levels (P < 0.001) and lower IL-10 concentrations (P < 0.001). Subjects undergoing NIV had a significant reduction of rehospitalizations during follow-up compared to oxygen group (P = 0.005). These findings were confirmed after propensity matching and pH stratification. Conclusions. These findings challenge prior paradigms based on the assumption that pulmonary inflammation is per se detrimental. NIV beneficial impact on lung mechanics may overcome the potential unfavorable effects of an increased inflammatory state.

Noninvasive ventilation and lung volume reduction

As parenchymal lung disease in chronic obstructive pulmonary disease becomes increasingly severe there is a diminishing prospect of drug therapies conferring clinically useful benefit. Lung volume reduction surgery is effective in patients with heterogenous upper zone emphysema and reduced exercise tolerance, and is probably underused. Rapid progress is being made in nonsurgical approaches to lung volume reduction, but use outside specialized centers cannot be recommended presently. Noninvasive ventilation given to patients with acute hypercapnic exacerbation of chronic obstructive pulmonary disease reduces mortality and morbidity, but the place of chronic non-invasive ventilatory support remains more controversial.

Noninvasive positive pressure ventilation in subjects with stable COPD: a randomized trial

BACKGROUND

The use of domiciliary noninvasive positive pressure ventilation (NPPV) in stable chronic obstructive pulmonary disease (COPD) with chronic hypercapnic respiratory failure has yielded variable effects on survival, quality of life, and dyspnea. We hypothesized that use of NPPV in stable COPD and partial pressure of carbon dioxide (PaCO2) <52 mmHg might result in improvement in quality of life and dyspnea.

METHODS

Thirty patients with stable COPD (forced expiratory volume in the first second <50% predicted and PaCO2 <52 mmHg) were prospectively randomized to receive domiciliary NPPV (bilevel positive airway pressure, 15/5 cm H2O) or usual therapy for 6 months. Measurements were made at baseline, 6 weeks, 3 months, and 6 months. Primary outcomes were quality of life as assessed by the Chronic Respiratory Disease Questionnaire (CRQ), and dyspnea as measured by the Transitional Dyspnea Index (TDI).

RESULTS

Fifteen subjects in the NPPV arm and 12 controls completed all the study visits. At 6 weeks and 3 months, the NPPV arm showed significant improvement in TDI total score. However, this effect persisted only in the TDI-Task at 6 months (P=0.03). NPPV use was associated with a small improvement in the CRQ-Mastery domain (0.6 versus -0.1, P=0.04). The arterial partial pressure of oxygen (PaO2) in the control arm worsened over the period of the study, whereas it remained stable in the NPPV arm (change -7.2 mmHg versus +2.1 mmHg, respectively, P=0.02).

CONCLUSION

NPPV resulted in a small improvement in quality of life indices in stable COPD patients with PaCO2 <52 mmHg. Future larger studies will clarify the role of NPPV in this stable subgroup of patients with COPD.

Admission prevention in COPD: non-pharmacological management

Exacerbations of chronic obstructive pulmonary disease (COPD) are one of the commonest causes of hospital admission in Europe, Australasia, and North America. These adverse events have a large effect on the health status of the patients and impose a heavy burden on healthcare systems. While we acknowledge the contribution of pharmacotherapies to exacerbation prevention, our interpretation of the data is that exacerbations continue to be a major burden to individuals and healthcare systems, therefore, there remains great scope for other therapies to influence exacerbation frequency and preservation of quality of life. In this review, the benefits and limitations of pulmonary rehabilitation, non-invasive ventilation, smoking cessation, and long-term oxygen therapy are discussed. In addition, supported discharge, advanced care coordination, and telehealth programs to improve clinical outcome are reviewed as future directions for the management of COPD.

Nocturnal non-invasive ventilation for cardio-respiratory disorders in adults

Following the classic 'iron lung' non-invasive negative pressure ventilator, non-invasive positive pressure ventilation (NIPPV), particularly used 'nocturnally' has developed a broad role in both the acute hospital setting and domiciliary long-term use for many cardio-respiratory disorders associated with acute and chronic ventilatory failure. This role is based in part upon the perceived relative ease of application and discontinuation of NIPPV, ability to avoid intubation or tracheostomy and their associated morbidities and availability of increasingly portable pressure and volume cycled NIPPV devices. Nevertheless, the many methodologies necessary for optimal NIPPV use are often underappreciated by health care workers and patients alike. This review focuses on the rationale, practice, and future directions for 'nocturnal' use of non-invasive positive pressure ventilation (nNIV) in cardio-respiratory disorders in adults which are commonly associated with sleep-related apnea, hypoventilation and hypoxemia: congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), obesity hypoventilation syndrome (OHS), cystic fibrosis (CF) and neuromuscular disorders.

Nocturnal noninvasive positive pressure ventilation in stable COPD: a systematic review and individual patient data meta-analysis

INTRODUCTION

The effects of nocturnal noninvasive positive pressure ventilation (NIPPV) in patients with stable chronic obstructive pulmonary disease (COPD) remain controversial.

METHODS

The Cochrane Airways group Register of Trials, MEDLINE, EMBASE and CINAHL were searched up to August 2012. Individual patient data from randomised controlled trials on NIPPV outcomes were selected for two separate meta-analyses: the first with follow-up of 3 months and the second with 12 months of follow-up. Additionally, subgroup analyses within the NIPPV group comparing IPAP levels, compliance and levels of hypercapnia on change in PaCO2 after 3 months were performed.

RESULTS

Seven trials (245 patients) were included. All studies were considered of moderate to high quality. No significant difference was found between NIPPV and control groups after 3 or 12 months of follow-up when looking at PaCO2 and PaO2, 6-minute walking distance, health-related quality-of-life, forced expiratory volume in 1 s, forced vital capacity, maximal inspiratory pressure and sleep efficiency. Significant differences in change in PaCO2 after 3 months were found for patients ventilated with IPAP levels of at least 18 cm H2O, for patients who used NIPPV for at least 5 h per night as well as for patients with baseline PaCO2 of at least 55 mm Hg when compared to patients with lower IPAP levels, poorer compliance or lower levels of hypercapnia.

DISCUSSION

At present, there is insufficient evidence to support the application of routine NIPPV in patients with stable COPD. However, higher IPAP levels, better compliance and higher baseline PaCO2 seem to improve PaCO2.

Leaks can dramatically decrease FiO2 on home ventilators: a bench study

Background

Long term oxygen therapy improves survival in hypoxemic patients with chronic obstructive pulmonary disease (COPD). Because pressure support ventilation with a home care ventilator is largely unsupervised, there is considerable risk of leakage occurring, which could affect delivered FiO₂. We have therefore conducted a bench study in order to measure the effect of different levels of O₂ supply and degrees of leakage on delivered FiO₂. Ventilator tested: Legendair® (Airox™, Pau, France). Thirty-six measures were performed in each four ventilators with zero, 5 and 10 l.min-1 leakage and 1,2,4 and 8 l O2 flow.

Findings

FiO₂ decreased significantly with 5 l.min-1 leakage for all O2 flow rates, and with 10 l.min-1 at 4 and 8 l.min-1 O2.

Conclusion

During application of NIV on home ventilators, leakage can dramatically decrease inspired FiO2 making it less effective. It is important to know the FiO2 dispensed when NIV is used for COPD at home. We would encourage industry to develop methods for FiO2 regulation Chronic use of NIV for COPD with controlled FiO2 or SpO2 requires further studys.

Nocturnal non-invasive positive pressure ventilation for stable chronic obstructive pulmonary disease

BACKGROUND

Non-invasive positive pressure ventilation (NIPPV) is effective in treating acute exacerbations of chronic obstructive pulmonary disease (COPD). Nocturnal non-invasive positive pressure ventilation (nocturnal-NIPPV) has been proposed as an intervention for stable hypercapnic patients with COPD.

OBJECTIVES

To assess the effects of nocturnal-NIPPV at home via nasal mask or face mask in people with COPD by using a meta-analysis based on individual patient data (IPD).

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register. We performed the latest search in August 2012.

SELECTION CRITERIA

Randomised controlled trials in people with stable COPD that compared nocturnal-NIPPV at home for at least five hours per night, for at least three consecutive weeks plus standard therapy with standard therapy alone.

DATA COLLECTION AND ANALYSIS

IPD were collected and two review authors assessed risk of bias independently.

MAIN RESULTS

This update of the systematic review on nocturnal-NIPPV in COPD (Wijkstra 2002), has led to the inclusion of three new studies, leading to seven included studies on 245 people. We obtained IPD for all participants in all included studies. The 95% confidence interval (CI) of all outcomes included zero. These included partial pressure of CO2 and O2 in arterial blood, six-minute walking distance (6MWD), health-related quality of life (HRQoL), forced expiratory volume in one second (FEV1), forced vital capacity (FVC), maximal inspiratory pressure (PImax) and sleep efficiency. The mean effect on 6MWD was small at 27.7 m and not statistically significant. Given the width of the 95% CI (-28.1 to 66.3 m), the real effect of NIPPV on 6MWD is uncertain and we cannot exclude an effect that is clinically significant (considering that the minimal clinically difference on 6MWD is around 26 m).

AUTHORS' CONCLUSIONS

Nocturnal-NIPPV at home for at least three months in hypercapnic patients with stable COPD had no consistent clinically or statistically significant effect on gas exchange, exercise tolerance, HRQoL, lung function, respiratory muscle strength or sleep efficiency. Meta-analysis of the two new long-term studies did not show significant improvements in blood gases, HRQoL or lung function after 12 months of NIPPV. However, the small sample sizes of these studies preclude a definite conclusion regarding the effects of NIPPV in COPD.

Polysomnography in stable COPD under non-invasive ventilation to reduce patient-ventilator asynchrony and morning breathlessness

BACKGROUND

Stable severe chronic obstructive pulmonary disease (COPD) patients with chronic hypercapnic respiratory failure treated by nocturnal bi-level positive pressure non-invasive ventilation (NIV) may experience severe morning deventilation dyspnea. We hypothesised that in these patients, progressive hyperinflation, resulting from inappropriate ventilator settings, leads to patient-ventilator asynchrony (PVA) with a high rate of unrewarded inspiratory efforts and morning discomfort.

METHODS

Polysomnography (PSG), diaphragm electromyogram and transcutaneous capnography (PtcCO(2)) under NIV during two consecutive nights using baseline ventilator settings on the first night, then, during the second night, adjustment of ventilator parameters under PSG with assessment of impact of settings changes on sleep, patient-ventilator synchronisation, morning arterial blood gases and morning dyspnea.

RESULTS

Eight patients (61 ± 8 years, FEV(1) 30 ± 8% predicted, residual volume 210 ± 30% predicted) were included. In all patients, pressure support was decreased during setting adjustments, as well as tidal volume, while respiratory rate increased without any deleterious effect on nocturnal PtcCO(2) or morning PaCO(2). PVA index, initially high (40 ± 30%) during the baseline night, decreased significantly after adjusting ventilator settings (p = 0.0009), as well as subjective perception of PVA leaks, and morning dyspnea while quality of sleep improved.

CONCLUSION

The subgroup of COPD patients treated by home NIV, who present marked deventilation dyspnea and unrewarded efforts may benefit from adjustment of ventilator settings under PSG or polygraphy.

Factors associated with noninvasive ventilation response in the first day of therapy in patients with hypercapnic respiratory failure

BACKGROUND AND AIM:

Noninvasive ventilation (NIV) decreases mechanical ventilation indication in the early period of acute hypercapnic respiratory failure (AHcRF) and factors for success have been studied well. But, less is known about the factors influencing the NIV response in the subacute period. This study was aimed to determine the factors influencing the reduction of PaCO₂ levels within first 24 hours of therapy.

METHODS:

NIV response was defined as reduction of PaCO₂ level below 50 mmHg within first 24 hours. Patients with AHcRF, treated with NIV, were divided into 2 groups according to this criterion; group 1 as the nonresponsive, group 2 as the responsive. The differences in NIV methods and characteristics of the two groups were evaluated and compared in this retrospective study.

RESULTS:

A total of 100 patients were included in the study; 66 of them in group 1 and 34 in group 2. No significant differences were identified between the length of NIV application and intensive care unit (ICU) stay, intubation and mortality rates, across the groups. Ninety-one percent of the patients in group 2 had received all night long NIV therapy; this was just 74% in group 1 (P=0.036). Results of multivariate analysis showed that while nocturnal application was significantly associated with better response, prior home ventilation and requirement of higher pressure support (PS) levels significantly and independently associated with poorer response to NIV therapy.

CONCLUSION:

In patients with AHcRF, all night long use of NIV may accelerate healing by improving PaCO₂ reduction within the first 24 hours. A rapid response in PaCO₂ levels should not be expected in patients requiring higher PS levels and using prior home ventilation.

[Non-invasive mechanical ventilation in COPD]

Non-invasive mechanical ventilation is the preferred method for the treatment of acute respiratory failure in patients with chronic obstructive pulmonary disease (COPD). Primary contraindications and stopping criteria must be regarded to avoid delaying endotracheal intubation. The primary interface is usually a nasal-oral mask. Cautious sedation can facilitate non-invasive ventilation in some patients. Under certain circumstances non-invasive ventilation may enable successful extubation in COPD patients with prolonged weaning. COPD patients can also benefit from preventive non-invasive ventilation in order to avoid re-intubation after a planned extubation. Domiciliary nocturnal non-invasive ventilation is an option for some patients with COPD in chronic hypercapnic respiratory failure. This treatment should be established in a specialised unit.

An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea

BACKGROUND

Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome.

PURPOSE

The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea.

METHODS

An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members.

RESULTS

Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains.

CONCLUSIONS

Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.

An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea

BACKGROUND

Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome.

PURPOSE

The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea.

METHODS

An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members.

RESULTS

Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains.

CONCLUSIONS

Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.

The role of non-invasive home mechanical ventilation in patients with chronic obstructive pulmonary disease requiring prolonged weaning

BACKGROUND AND OBJECTIVE

Patients with COPD who require prolonged weaning from invasive mechanical ventilation show poor long-term survival. Whether non-invasive home mechanical ventilation (HMV) has a beneficial effect after prolonged weaning has not yet been clearly determined.

METHODS

Patients with COPD who required prolonged weaning and were admitted to a specialized weaning centre between January 2002 and February 2008 were enrolled in the study. Long-term survival and prognostic factors, including the role of non-invasive HMV, were evaluated.

RESULTS

Of 117 patients (87 men, 30 women; mean age 69.5±9.5 years) included in the study, weaning from invasive ventilation was achieved in 82 patients (70.1%). Successful weaning was associated with better survival 1 year after discharge from hospital (hazard ratio (HR) 2.24, 95% CI: 1.16-4.31; P=0.016). Among the 82 patients who were successfully weaned, non-invasive HMV was initiated in 39 (47.6%) due to persistent chronic ventilatory failure. Initiation of HMV was associated with a higher rate of survival to 1 year as compared with patients who did not receive ventilatory support (84.2% vs 54.3%; HR 3.68, 95% CI: 1.43-9.43; P=0.007). In addition, younger age and higher PaO₂, haemoglobin concentration and haematocrit at discharge were associated with better survival. In an adjusted multivariate analysis, initiation of non-invasive HMV after successful weaning remained an independent prognostic factor for survival to 1 year (HR 3.63, 95% CI: 1.23-10.75; P=0.019).

CONCLUSIONS

These findings suggest that based on the potential for improvement in long-term survival, non-invasive HMV should be considered in patients with severe COPD and persistent chronic hypercapnic respiratory failure after prolonged weaning.

The effects of long-term noninvasive ventilation in hypercapnic COPD patients: a randomized controlled pilot study

Introduction

Noninvasive ventilation (NIV) is a well-established treatment for acute-on- chronic respiratory failure in hypercapnic COPD patients. Less is known about the effects of a long-term treatment with NIV in hypercapnic COPD patients and about the factors that may predict response in terms of improved oxygenation and lowered CO₂ retention.

Methods

In this study, we randomized 15 patients to a routine pharmacological treatment (n = 5, age 66 [standard deviation ± 6] years, FEV₁ 30.5 [±5.1] %pred, PaO₂ 65 [±6] mmHg, PaCO₂ 52.4 [±6.0] mmHg) or to a routine treatment and NIV (using the Synchrony BiPAP device [Respironics, Inc, Murrsville, PA]) (n = 10, age 65 [±7] years, FEV₁ 29.5 [±9.0] %pred, PaO₂ 59 [±13] mmHg, PaCO₂ 55.4 [±7.7] mmHg) for 6 months. We looked at arterial blood gasses, lung function parameters and performed a low-dose computed tomography of the thorax, which was later used for segmentation (providing lobe and airway volumes, iVlobe and iVaw) and post-processing with computer methods (providing airway resistance, iRaw) giving overall a functional image of the separate airways and lobes.

Results

In both groups there was a nonsignificant change in FEV₁ (NIV group 29.5 [9.0] to 38.5 [14.6] %pred, control group 30.5 [5.1] to 36.8 [8.7] mmHg). PaCO₂ dropped significantly only in the NIV group (NIV: 55.4 [7.7] → 44.5 [4.70], P = 0.0076; control: 52.4 [6.0] → 47.6 [8.2], NS). Patients actively treated with NIV developed a more inhomogeneous redistribution of mass flow than control patients. Subsequent analysis indicated that in NIV-treated patients that improve their blood gases, mass flow was also redistributed towards areas with higher vessel density and less emphysema, indicating that flow was redistributed towards areas with better perfusion. There was a highly significant correlation between the % increase in mass flow towards lobes with a blood vessel density of >9% and the increase in PaO₂. Improved ventilation–perfusion match and recruitment of previously occluded small airways can explain the improvement in blood gases.

Conclusion

We can conclude that in hypercapnic COPD patients treated with long-term NIV over 6 months, a mass flow redistribution occurs, providing a better ventilation–perfusion match and hence better blood gases and lung function. Control patients improve homogeneously in iVaw and iRaw, without improvement in gas exchange since there is no improved ventilation/perfusion ratio or increased alveolar ventilation. These differences in response can be detected through functional imaging, which gives a more detailed report on regional lung volumes and resistances than classical lung function tests do. Possibly only patients with localized small airway disease are good candidates for long-term NIV treatment. To confirm this and to see if better arterial blood gases also lead to better health related quality of life and longer survival, we have to study a larger population.

Two-year home-based nocturnal noninvasive ventilation added to rehabilitation in chronic obstructive pulmonary disease patients: a randomized controlled trial

BACKGROUND

The use of noninvasive intermittent positive pressure ventilation (NIPPV) in chronic obstructive pulmonary disease (COPD) patients with chronic hypercapnic respiratory failure remains controversial as long-term data are almost lacking. The aim was to compare the outcome of 2-year home-based nocturnal NIPPV in addition to rehabilitation (NIPPV + PR) with rehabilitation alone (PR) in COPD patients with chronic hypercapnic respiratory failure.

METHODS

Sixty-six patients could be analyzed for the two-year home-based follow-up period. Differences in change between the NIPPV + PR and PR group were assessed by a linear mixed effects model with a random effect on the intercept, and adjustment for baseline values. The primary outcome was health-related quality of life (HRQoL); secondary outcomes were mood state, dyspnea, gas exchange, functional status, pulmonary function, and exacerbation frequency.

RESULTS

Although the addition of NIPPV did not significantly improve the Chronic Respiratory Questionnaire compared to rehabilitation alone (mean difference in change between groups -1.3 points (95% CI: -9.7 to 7.4)), the addition of NIPPV did improve HRQoL assessed with the Maugeri Respiratory Failure questionnaire (-13.4% (-22.7 to -4.2; p = 0.005)), mood state (Hospital Anxiety and Depression scale -4.0 points (-7.8 to 0.0; p = 0.05)), dyspnea (Medical Research Council -0.4 points (-0.8 to -0.0; p = 0.05)), daytime arterial blood gases (PaCO2 -0.4 kPa (-0.8 to -0.2; p = 0.01); PaO2 0.8 kPa (0.0 to 1.5; p = 0.03)), 6-minute walking distance (77.3 m (46.4 to 108.0; p < 0.001)), Groningen Activity and Restriction scale (-3.8 points (-7.4 to -0.4; p = 0.03)), and forced expiratory volume in 1 second (115 ml (19 to 211; p = 0.019)). Exacerbation frequency was not changed.

CONCLUSIONS

The addition of NIPPV to pulmonary rehabilitation for 2 years in severe COPD patients with chronic hypercapnic respiratory failure improves HRQoL, mood, dyspnea, gas exchange, exercise tolerance and lung function decline. The benefits increase further with time.

TRIAL REGISTRATION

ClinicalTrials.Gov (ID NCT00135538).

Home mechanical ventilation: a Canadian Thoracic Society clinical practice guideline

Increasing numbers of patients are surviving episodes of prolonged mechanical ventilation or benefitting from the recent availability of userfriendly noninvasive ventilators. Although many publications pertaining to specific aspects of home mechanical ventilation (HMV) exist, very few comprehensive guidelines that bring together all of the current literature on patients at risk for or using mechanical ventilatory support are available. The Canadian Thoracic Society HMV Guideline Committee has reviewed the available English literature on topics related to HMV in adults, and completed a detailed guideline that will help standardize and improve the assessment and management of individuals requiring noninvasive or invasive HMV. The guideline provides a disease-specific review of illnesses including amyotrophic lateral sclerosis, spinal cord injury, muscular dystrophies, myotonic dystrophy, kyphoscoliosis, post-polio syndrome, central hypoventilation syndrome, obesity hypoventilation syndrome, and chronic obstructive pulmonary disease as well as important common themes such as airway clearance and the process of transition to home. The guidelines have been extensively reviewed by international experts, allied health professionals and target audiences. They will be updated on a regular basis to incorporate any new information.

A randomised crossover trial comparing volume assured and pressure preset noninvasive ventilation in stable hypercapnic COPD

Recent randomised controlled trials suggest non-invasive ventilation may offer benefit in the long-term management of ventilatory failure in stable COPD. The best mode of ventilation is unknown and newer volume assured modes may offer advantages by optimising ventilation overnight when treatment is delivered. This study compares volume assured with pressure preset non-invasive ventilation. Randomised crossover trial including twenty five subjects previously established on long-term non-invasive ventilation to manage COPD with chronic ventilatory failure. Two 8-week treatment periods of volume assured and pressure preset non-invasive ventilation. The primary outcomes were daytime arterial blood gas tensions and mean nocturnal oxygen saturation. Secondary outcomes included lung function, exercise capacity, mean nocturnal transcutaneous carbon dioxide, health status and compliance. No significant differences were seen in primary or secondary outcomes following 8 weeks of treatment when comparing volume assured and pressure preset ventilation. Primary outcomes assessed: mean (standard deviation) PaO(2) 7.8 (1.2) vs 8.1(1) kPa, PaCO(2) 6.7 (1.1) vs 6.3 (1.2) kPa and mean nocturnal oxygenation 90 (4) vs 91 (3)% volume assured versus pressure preset, respectively. Volume assured and pressure preset non-invasive ventilation appear equally effective in the long-term management of ventilatory failure associated with stable COPD.

PaCO2 six months after the initiation of long-term noninvasive ventilation in patients with COPD

BACKGROUND AND OBJECTIVE

The appropriate target level for PaCO(2) after the introduction of long-term noninvasive positive pressure ventilation (NPPV) in patients with COPD remains uncertain, and therefore must be tested.

METHODS

Data on 54 patients with COPD receiving long-term domiciliary NPPV were examined retrospectively. PaCO(2) a few months after NPPV and potential confounders were analyzed with discontinuation of long-term NPPV as the primary outcome. The differences in annual hospitalization rates due to respiratory deterioration between those from 1 year before to 2 years after initiation of NPPV were compared according to the PaCO(2) measured at 6 months after NPPV (6-mo PaCO(2)).

RESULTS

6-mo PaCO(2) seemed to be most related to continuation of NPPV (p=0.019). Patients with 6-mo PaCO(2) of less than 60 mmHg had maintained a significantly lower PaCO(2) value 6 to 24 months after NPPV (p=0.04) and had a significantly higher continuation rate of NPPV (p=0.03) than those with a 6-mo PaCO(2) of 60 mmHg or more. Annual hospitalization rates due to respiratory deterioration were not associated with the 6-mo PaCO(2) level, but fatal hospitalization rates during the first year of NPPV were significantly correlated with relatively high 6-mo PaCO(2) (p=0.008).

CONCLUSION

A relatively low 6-mo PaCO(2) value was predictive of long-term use of NPPV. The target values of 6-mo PaCO(2) may, therefore, be less than 60 mmHg in COPD patients with extremely severe hypercapnia, although more prospective studies are needed.

Effects of long-term non-invasive home mechanical ventilation on chronic respiratory failure

OBJECTIVE

Chronic respiratory failure (CRF) is a syndrome defined by certain disturbances in arterial blood gases. Non-invasive mechanical ventilation (NIMV) is an increasingly used treatment modality in respiratory failure. The aim of this study was to investigate the long-term effects of NIMV on pulmonary function and survival of patients with CRF.

METHODS

The study enrolled 170 CRF patients who it was decided should receive long-term home mechanical ventilation. Patients were stratified into two distinct groups - Group I (patients for whom NIMV was recommended and who had used it) and Group II (patients for whom NIMV was recommended at least 1 year ago but who had not used it for various reasons). Best arterial blood gas and pulmonary function test values in the year before the NIMV recommendation were obtained from patient records. The same tests were performed at least 1 year (1-5 years) after initiation of NIMV therapy in Group I patients and at least 1 year (1-5 years) after prescription of the device in Group II.

RESULTS

In the assessments performed 1 year after NIMV recommendation, no difference was found between groups in terms of hospital admissions. However, in Group I, intra-group analysis showed a reduction in the number of hospitalizations 1 year after NIMV. A marked reduction in PaCO(2) level was found in Group I patients 1 year after NIMV therapy. Mean survival after NIMV recommendation was 40.27 +/- 3.56 months in Group I, and 27.35 +/- 3.68 months in Group II (log rank = 7.79; p = 0.005). It was found that survival time increased as duration of NIMV usage increased.

CONCLUSION

NIMV therapy has some important and significant benefits in patients with hypercapnic chronic respiratory failure. This study has some limitations in terms of patient selection, power analysis and survival analysis. To assess the effects of NIMV on mortality and pulmonary functions, the authors believe that there is need for prospective, controlled, multicentre studies with longer follow-up periods, improved adherence and novel ventilator modes and settings.

Chronic obstructive pulmonary disease: an update on diagnosis and management issues in older adults

Chronic obstructive pulmonary disease (COPD) is a debilitating disease of the elderly that causes significant morbidity and mortality. Despite being a treatable and preventable disease, the prevalence continues to rise because of the worldwide epidemic of smoking. COPD is associated with enormous healthcare costs. It has systemic effects, and common co-morbid conditions such as cardiovascular disease, muscle wasting and osteoporosis may all be linked through a common systemic inflammatory cascade. Depression, anxiety and malnutrition are also common in elderly COPD patients. These factors not only affect quality of life (QOL) but also compliance with therapy. Malnutrition is an independent predictor of mortality and poor outcome. Spirometry is essential for the diagnosis of COPD, but the criteria defining airflow limitation are not clear cut for elderly patients and could result in over-diagnosis. However, older patients perceive their symptoms differently, and COPD could also be under-diagnosed in this population. Acute exacerbations result in worsening symptoms that necessitate additional treatment, and may cause a more rapid decline in lung function and QOL. The management of elderly patients with COPD should encompass a multidisciplinary approach. An evaluation of patients' nutritional status and mental health should be undertaken, in addition to assessing their lung function and functional impairment. Significant underlying co-morbidities should be evaluated and treated to derive the maximal benefit of therapy. Specific therapy for COPD should start with cessation of exposure to the most important risk factor, tobacco smoke. Smoking cessation rates in the elderly have not declined, and this may reflect an underlying reluctance by physicians to counsel and offer smoking cessation therapies to the elderly. Unlike oxygen therapy in hypoxaemic patients, bronchodilators and corticosteroids do not decrease mortality in COPD patients and they are primarily directed towards symptom relief. However, they do have a positive effect on QOL and exacerbation rates. The choice of delivery devices for inhaled medications is important in the elderly, and patients' inhaler technique and manual dexterity should be frequently assessed. Pulmonary rehabilitation and nutritional supplementation are other important components of care. End-of-life issues should be adequately addressed in the elderly with COPD, and an approach integrating curative and palliative interventions is recommended.

Respiratory muscle unloading during auto-adaptive non-invasive ventilation

RATIONALE

Non-invasive ventilation (NIV) has been shown to improve clinical outcomes in acute and chronic hypercapnic respiratory failure. A new timed, automated, auto-adaptive non-invasive ventilatory mode (TA-mode) has been recently introduced.

OBJECTIVE

To investigate the degree of respiratory muscle unloading with this new mode in comparison to assisted (S-mode) NIV in healthy individuals.

METHODS

Work of breathing, pressure time product and transdiaphragmatic pressure time product were measured during unassisted breathing, assisted and TA-mode-NIV in eight healthy, awake volunteers at inspiratory pressures of 20 and expiratory pressures of 4hPa.

RESULTS

Assisted and TA-mode-NIV reduced the work of breathing by 50 and 89.1%, pressure time product by 61.5 and 72.6% and transdiaphragmatic pressure time product by 77 and 88.7%, respectively when compared to unassisted breathing. The degree of respiratory muscle unloading was higher during TA-mode-NIV when compared to assisted non-invasive ventilation (work of breathing p<0.001, pressure time product p=0.04 and transdiaphragmatic pressure time product p=0,01).

CONCLUSION

TA-mode-NIV achieved significant higher levels of respiratory muscle unloading in healthy individuals when compared to assisted non-invasive ventilation.