Health-related quality of life and long-term prognosis in chronic hypercapnic respiratory failure: a prospective survival analysis

Home non-invasive ventilation: An observational study of aetiology, chronic respiratory failure of multiple aetiologies, survival and treatment adherence

Home non-invasive ventilation (NIV) is used to treat patients with chronic respiratory failure (CRF). However, knowledge on the prevalence and impact of multimorbid aetiology of CRF, patterns of NIV use, and survival of these patients is limited. Our aim was to analyse the multiple aetiologies of CRF, patterns of NIV use and the outcome of those patients. We conducted a retrospective analysis of 1,281 patients treated with home-NIV between 2004 and 2014 in Turku University Hospital, Finland. The patients were divided into nine disease categories: obstructive airways disease (16 %); obesity hypoventilation syndrome (11 %); neuromuscular disease (10 %); chest wall diseases (4 %); sleep apnoea (26 %); interstitial lung diseases (3 %); malignancy (2 %); other (3 %) and acute (8 %), which refers to the patients who did not fulfil criteria of CRF. In addition, multiple aetiologies of CRF were found in 17 %. Mean adherence to home-NIV was 6.0 ± 4.4 h/d and median treatment duration 410 (120-1021) days. Adherence, treatment duration or survival did not significantly differ between patients with either single or multiple causative diseases leading to CRF. Median survival was 4.5 years (95 % CI 3.6 to 5.4). The main reasons for discontinuing NIV were death (56 %) and lack of motivation (19 %). We conclude that home-NIV is used in a variety of diseases. CRF of multiple aetiologies is prevalent and not limited to chronic obstructive lung disease and obstructive sleep apnoea overlap syndrome. However, the adherence to home-NIV or survival did not differ between patients with a single or multiple diseases causing CRF, but the survival of the home-NIV patients differed according to the underlying aetiology of CRF.

Obesity hypoventilation syndrome, literature review

Obesity is a global health concern that has been increasing over the years, and it is associated with several pathophysiological changes affecting the respiratory system, including alveolar hypoventilation. Obesity hypoventilation syndrome (OHS) is one of the six subtypes of sleep-hypoventilation disorders. It is defined as the presence of obesity, chronic alveolar hypoventilation leading to daytime hypercapnia and hypoxia, and sleep-disordered breathing. The existence of a sleep disorder is one of the characteristics that patients with OHS present. Among them, 90% of patients have obstructive sleep apnea (OSA), and the remaining 10% of patients with OHS have non-obstructive sleep hypoventilation without OSA or with mild OSA. This review aims to provide a comprehensive understanding of the epidemiological and pathophysiological impact of OHS and to highlight its clinical features, prognosis, and severity, as well as the available treatment options.

The Role of Obstructive Sleep Apnea in Hypercapnic Respiratory Failure Identified in Critical Care, Inpatient, and Outpatient Settings

An emerging body of literature describes the prevalence and consequences of hypercapnic respiratory failure. While device qualifications, documentation practices, and previously performed clinical studies often encourage conceptualizing patients as having a single "cause" of hypercapnia, many patients encountered in practice have several contributing conditions. Physiologic and epidemiologic data suggest that sleep-disordered breathing-particularly obstructive sleep apnea (OSA)-often contributes to the development of hypercapnia. In this review, the authors summarize the frequency of contributing conditions to hypercapnic respiratory failure among patients identified in critical care, emergency, and inpatient settings with an aim toward understanding the contribution of OSA to the development of hypercapnia.

Inspiratory Muscle Dysfunction Mediates and Predicts a Disease Continuum of Hypercapnic Failure in Chronic Obstructive Pulmonary Disease

INTRODUCTION

Advanced chronic obstructive pulmonary disease (COPD) is associated with chronic hypercapnic failure. The present work aimed to comprehensively investigate inspiratory muscle function as a potential key determinant of hypercapnic respiratory failure in patients with COPD.

METHODS

Prospective patient recruitment encompassed 61 stable subjects with COPD across different stages of respiratory failure, ranging from normocapnia to isolated nighttime hypercapnia and daytime hypercapnia. Arterialized blood gas analyses and overnight transcutaneous capnometry were used for patient stratification. Assessment of respiratory muscle function encompassed body plethysmography, maximum inspiratory pressure (MIP), diaphragm ultrasound, and transdiaphragmatic pressure recordings following cervical magnetic stimulation of the phrenic nerves (twPdi) and a maximum sniff manoeuvre (Sniff Pdi).

RESULTS

Twenty patients showed no hypercapnia, 10 had isolated nocturnal hypercapnia, and 31 had daytime hypercapnia. Body plethysmography clearly distinguished patients with and without hypercapnia but did not discriminate patients with isolated nocturnal hypercapnia from those with daytime hypercapnia. In contrast to ultrasound parameters and transdiaphragmatic pressures, only MIP reflected the extent of hypercapnia across all three stages. MIP values below -48 cmH2O predicted nocturnal hypercapnia (area under the curve = 0.733, p = 0.052).

CONCLUSION

In COPD, inspiratory muscle dysfunction contributes to progressive hypercapnic failure. In contrast to invasive tests of diaphragm strength only MIP fully reflects the pathophysiological continuum of hypercapnic failure and predicts isolated nocturnal hypercapnia.

Hypercapnia and its relationship with respiratory infections

INTRODUCTION

Hypercapnia is developed in patients with acute and/or chronic respiratory conditions. Clinical data concerning hypercapnia and respiratory infections interaction is limited.

AREAS COVERED

Currently, the relationship between hypercapnia and respiratory infections remains unclear. In this review, we summarize studies on the effects of hypercapnia on models of pulmonary infections to clarify the role of elevated CO2 in these pulmonary pathologies. Hypercapnia affects different cell types in the alveoli, leading to changes in the immune response. In vitro studies show that hypercapnia downregulates the NF-κβ pathway, reduces inflammation and impairs epithelial wound healing. While in vivo models show a dual role between short- and long-term effects of hypercapnia on lung infection. However, it is still controversial whether the effects observed under hypercapnia are pH dependent or not.

EXPERT OPINION

The role of hypercapnia is still a controversial debate. Hypercapnia could play a beneficial role in mechanically ventilated models, by lowering the inflammation produced by the stretch condition. But it could be detrimental in infectious scenarios, causing phagocyte dysfunction and lack of infection control. Further data concerning hypercapnia on respiratory infections is needed to elucidate this interaction.

Home noninvasive ventilation in severe COPD: in whom does it work and how?

Background

Not all hypercapnic COPD patients benefit from home noninvasive ventilation (NIV), and mechanisms through which NIV improves clinical outcomes remain uncertain. We aimed to identify "responders" to home NIV, denoted by a beneficial effect of NIV on arterial partial pressure of carbon dioxide (PaCO2), health-related quality of life (HRQoL) and survival, and investigated whether NIV achieves its beneficial effect through an improved PaCO2.

Methods

We used individual patient data from previous published trials collated for a systematic review. Linear mixed-effect models were conducted to compare the effect of NIV on PaCO2, HRQoL and survival, within subgroups defined by patient and treatment characteristics. Secondly, we conducted a causal mediation analysis to investigate whether the effect of NIV is mediated by a change in PaCO2.

Findings

Data of 1142 participants from 16 studies were used. Participants treated with lower pressure support (<14 versus ≥14 cmH2O) and with lower adherence (<5 versus ≥5 h·day-1) had less improvement in PaCO2 (mean difference (MD) -0.30 kPa, p<0.001 and -0.29 kPa, p<0.001, respectively) and HRQoL (standardised MD 0.10, p=0.002 and 0.11, p=0.02, respectively), but this effect did not persist to survival. PaCO2 improved more in patients with severe dyspnoea (MD -0.30, p=0.02), and HRQoL improved only in participants with fewer than three exacerbations (standardised MD 0.52, p=0.03). The results of the mediation analysis showed that the effect on HRQoL is mediated partially (23%) by a change in PaCO2.

Interpretation

With greater pressure support and better daily NIV usage, a larger improvement in PaCO2 and HRQoL is achieved. Importantly, we demonstrated that the beneficial effect of home NIV on HRQoL is only partially mediated through a reduction in diurnal PaCO2.

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.

Effect of Respiratory Events on Health-Related Quality of Life in Patients Treated with Long-Term Noninvasive Ventilation

BACKGROUND

Long-term noninvasive ventilation (NIV) can increase or maintain health-related quality of life (HRQoL) for patients with chronic hypercapnic respiratory failure (CHRF). Evidence from studies systematically assessing how NIV-specific factors influence HRQoL is limited.

OBJECTIVES

The objective of this study was to describe HRQoL measured by the Severe Respiratory Insufficiency Questionnaire (SRI) in patients with CHRF treated with long-term NIV and to analyze the associations between HRQoL and hypoxemia, hypercapnia, and respiratory events such as apneas, hypopneas (AHI), and patient ventilator asynchrony (PVA) occurring during long-term NIV.

METHODS

We included sixty-seven stable patients with established long-term NIV due to neuromuscular disease or thoracic cage disorders in a prospective cross-sectional study at Oslo University Hospital. Patients answered the SRI and underwent daytime arterial blood gases, nocturnal pulse oximetry, sleep polygraphy, and nocturnal transcutaneous CO2.

RESULTS

The mean global SRI for 62 patients was 64.8 ± 14.5, with the highest score in SRI Social Relationships (79.5 ± 15.6). There were no differences in HRQoL between the different patient groups. Compliant patients had a significantly higher score in SRI Attendant and Sleep. Residual nocturnal hypoxemia affected both the subscale SRI "Respiratory Complaints" and SRI "Attendant Symptoms and Sleep." Persisting daytime hypercapnia, nocturnal hypoventilation, and high AHI affected the subscale SRI "Anxiety" negatively, while frequent PVA was associated with a lower score in SRI "Physical Function."

CONCLUSION

In a group of patients with long-term NIV, undesired respiratory events during NIV are associated with lower HRQoL in several of the SRI subscales. We suggest designing interventional studies to confirm the possible relationship between HRQoL and respiratory events during long-term NIV.

The Role of Long-Term Noninvasive Ventilation in Chronic Stable Hypercapnic Chronic Obstructive Pulmonary Disease

Despite the heterogeneity of data on the role of noninvasive ventilation (NIV) in severe stable chronic obstructive pulmonary disease with chronic hypercapnia, the current evidence supports the use of NIV in select populations and phenotypes. The Center for Medicare and Medicaid Services reimbursement criteria are complex, and the practice of navigating the most efficient method to initiate NIV therapy continues to be challenging. These patients optimally require referral to a medical center that has physicians with specific training in pulmonary and sleep medicine, who can navigate the specific needs for the use of NIV.

Comparing the quality of care for long-term ventilated individuals at home versus in shared living communities: a convergent parallel mixed-methods study

BACKGROUND

People on home mechanical ventilation (HMV) belong to a heterogeneous population with complex care needs. In Germany, outpatient intensive care is provided in people's private home (PH) or in shared living communities (SLC). Increasing patient numbers have led to criticism of the quality of care in recent years. Since quality deficits from the perspective of those affected are largely unclear, the following research question emerged: How do interviews with ventilated individuals and family caregivers explain any differences or similarities in the quality of care between PH and SLC?

METHODS

This study used a mixed-methods convergent parallel design, where quantitative and qualitative components were separately collected and analysed. The quantitative component (structured interviews and online survey) included ventilation characteristics, health-related resource use, health-related quality of life (HRQL) measured with the Severe Respiratory Insufficiency Questionnaire (SRI; range 0-100; higher scores indicated higher HRQL) and the Burden Scale of the Family Caregivers short version (BSFC-s; range 0-30; higher scores indicated higher burden). The qualitative component (semi-structured interviews) focused on people's experience of person-centred care. Data were merged using a weaving method and the Picker framework of Person-Centred Care.

RESULTS

The quantitative component revealed that ventilated individuals living in PHs were on average 20 years younger than participants living in SLCs (n = 46; PH: 46.86 ±15.40 years vs. SLC: 65.07 ±11.78 years; p = .001). HRQL (n = 27; PH: 56.62 ±16.40 vs. SLC: 55.35 ±12.72; p > .999) and the burden of family caregivers (n = 16; PH: 13.20 ±10.18 vs. SLC: 12.64 ±8.55; p > .999) were not significantly different between living situation. The qualitative component revealed that person-centred care is possible in both care settings (ventilated individuals: n = 13; family caregivers: n = 18).

CONCLUSION

This study describes a care situation that is as heterogeneous as the population of people with HMV. HRQL and the burden of family caregivers are highly individual and, like person-centred care, independent of the living situation. Policy decisions that facilitate person-centred care need to recognise that quality of care is highly individual and starts with the free choice of the care setting.

Hypercapnia in COPD: Causes, Consequences, and Therapy

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder that may lead to gas exchange abnormalities, including hypercapnia. Chronic hypercapnia is an independent risk factor of mortality in COPD, leading to epithelial dysfunction and impaired lung immunity. Moreover, chronic hypercapnia affects the cardiovascular physiology, increases the risk of cardiovascular morbidity and mortality, and promotes muscle wasting and musculoskeletal abnormalities. Noninvasive ventilation is a widely used technique to remove carbon dioxide, and several studies have investigated its role in COPD. In the present review, we aim to summarize the causes and effects of chronic hypercapnia in COPD. Furthermore, we discuss the use of domiciliary noninvasive ventilation as a treatment option for hypercapnia while highlighting the controversies within the evidence. Finally, we provide some insightful clinical recommendations and draw attention to possible future research areas.

Comparative effectiveness of smartphone healthcare applications for improving quality of life in lung cancer patients: study protocol

BACKGROUND

Although pulmonary rehabilitation is helpful for patients following lung cancer surgery, rehabilitation is not widely available, due in part to a lack of medical resources. Recent developments in digital health care have overcome the space limitations associated with in-person health care. This study will evaluate and compare the efficacy of three different smartphone healthcare systems in patients with lung cancer.

METHODS

This single center randomized controlled study is designed to evaluate the efficacy of digital healthcare applications for lung cancer patients after thoracoscopic lung resection. A total of 320 patients will be enrolled and randomized 1:1:1:1 into four different groups, with one group each using the smartphone applications NOOM, Walkon, and Efilcare and the fourth being the control group without intervention. Questionnaires will be administered to patients at baseline and after 3, 6, and 12 months. The primary endpoint will be the score on the EuroQol five-dimension index. Secondary endpoints will include other questionnaires about quality of life and dyspnea.

DISCUSSION

This prospective randomized controlled study may allow assessments and comparisons of the efficacy of various smartphone applications in patients who undergo lung cancer surgery. This process may enable the introduction of healthcare interventions that maintain quality of life in patients with lung cancer. Trial registration CRIS, KCT0005447. Registered 06 October 2020, https://cris.nih.go.kr/cris/search/detailSearch.do/19346.

Exploring red cell distribution width as a biomarker for treatment efficacy in home mechanical ventilation

BACKGROUND

With the growing practice of home mechanical ventilation, there is a need to identify biological markers for adequate follow-up. Red cell distribution width (RDW) is a promising candidate because it is convenient, objective and may reflect treatment effect over a long period of time. The aim of this study was to explore the possible role of RDW as a marker for home mechanical ventilation in real-life, unselected chronic respiratory patient populations.

METHODS

First, we identified characteristic RDW values for mixed case, unselected chronic respiratory failure and home mechanical ventilated patients through retrospective review within our institutional database. Next, we conducted a prospective observational study to identify RDW changes during the first six months of optimized home mechanical ventilation treatment. Adult patients starting home mechanical ventilation were included. Factors affecting RDW change during the first 6 months of treatment were analysed.

RESULTS

RDW was elevated in both chronic respiratory failure and home mechanical ventilation patients compared to healthy individuals in the retrospective review. In the prospective study of 70 patients, we found that 55.4% of patients starting home mechanical ventilation have abnormal RDW values which are reduced from 14.7 (IQR = 13.2-16.2)% to 13.5 (IQR = 13.1-14.6)% during the first 6 months of HMV treatment (p < 0.001). RDW improvement correlates with improvement in self-reported health-related quality of life and sleepiness scale scores, as well as physical functional status during the same time frame. RDW proved to be a comparable marker to other parameters traditionally used to evaluate treatment efficacy.

CONCLUSIONS

RDW is elevated in chronic respiratory failure patients and is significantly reduced in the first six months of optimized home mechanical ventilation. Although further research is needed to verify if RDW change reflects outcome and how comorbidities influence RDW values, our results suggest that RDW is a promising marker of home mechanical ventilation efficacy. Trial registration This study was approved by and registered at the ethics committee of Semmelweis University (TUKEB 250/2017 and TUKEB 250-1/2017, 20th of December 2017 and 1st of October 2019).

Elucidating Predictors of Obesity Hypoventilation Syndrome in a Large Bariatric Surgery Cohort

Rationale: Although understanding predictors of obesity hypoventilation syndrome (OHS), a condition associated with increased morbidity and mortality, is of key importance for risk prediction, existing characterization is limited.Objectives: We hypothesize that OHS patients referred for bariatric surgery have more severe obstructive sleep apnea and metabolic derangements compared with their eucapnic counterparts.Methods: A total of 1,718 patients undergoing polysomnography with end-tidal CO₂ monitoring prior to bariatric surgery at Cleveland Clinic from September 2011 to September 2018 were included. OHS was defined by body mass index (BMI) ≥ 30 kg/m² and either polysomnography-based end-tidal CO₂ ≥ 45 mm Hg or serum bicarbonate levels ≥ 27 mEq/L based on the updated European Respiratory Society guidelines. Unadjusted and multivariable logistic regression models (odds ratio; 95% confidence interval) were used to examine OHS predictors consisting of factors in domains of patient characteristics, polysomnography (cardiorespiratory and sleep architecture), laboratory, and metabolic parameters.Results: The analytic sample comprised 1,718 patients with the following characteristics: age of 45.3 ± 12.1 years, 20.7% were male, BMI = 48.6 ± 9 kg/m², and 63.6% were white individuals. OHS prevalence was 68.4%. Unadjusted analyses revealed a 1.5% increased odds of OHS (1.01; 1.00-1.03) per 1-unit BMI increase, 1.7% (1.02; 1.01-1.02) per 1% increase in sleep time Sa_O2 < 90%, 12% increase (1.12; 1.03-1.22) per 1-U increase in hemoglobin A1c, and 3.4% increased odds (1.03; 1.02-1.05) per 5-U increase in apnea-hypopnea index. The association of apnea-hypopnea index with OHS persisted after adjustment for age, sex, race, and BMI and its comorbidities (1.02; 1.01-1.04).Conclusions: OHS was highly prevalent in patients referred for bariatric surgery by more than two-thirds. Even after consideration of confounders including obesity, obstructive sleep apnea remained a strong OHS predictor, as were increasing age, male sex, nocturnal hypoxia, and impaired long-term glucose control. These findings can inform OHS risk stratification in bariatric surgery and set the stage for experimental studies to examine sleep-related respiratory and metabolic contributions to hypoventilation.

Cardiovascular disease in obesity hypoventilation syndrome - A review of potential mechanisms and effects of therapy

Cardiovascular disease is common in patients with obesity hypoventilation syndrome (OHS) and accounts in part for their poor prognosis. This narrative review article examines the epidemiology of cardiovascular disease in obesity hypoventilation syndrome, explores possible contributing factors and the effects of therapy. All studies that included cardiovascular outcomes and biomarkers were included. Overall, there is a higher burden of cardiovascular disease and cardiovascular risk factors among patients with obesity hypoventilation syndrome. In addition to obesity and sleep-disordered breathing, there are several other pathophysiological mechanisms that contribute to higher cardiovascular morbidity and mortality in OHS. There is evidence emerging that positive airway pressure therapy and weight loss have beneficial effects on the cardiovascular system in obesity hypoventilation syndrome patients, but further research is needed to clarify whether this translates to clinically important outcomes.

Ventilatory response to exercise is preserved in patients with obesity hypoventilation syndrome

STUDY OBJECTIVES

Blunted ventilatory responses to hypoxia and hypercapnia during resting conditions are common findings in patients with obesity hypoventilation syndrome (OHS). Exercise increases the work and oxygen cost of breathing and produces excessive carbon dioxide (CO₂). The aim of this investigation was to study ventilatory responses to incremental exercise in patients with OHS.

METHODS

Sixty-eight obese adults with OHS (n = 15), eucapnic obstructive sleep apnea (n = 26), or simple obesity (n = 27) participated in an incremental exercise test on a cycle ergometer and an in-laboratory sleep study.

RESULTS

The peak oxygen uptake (peak VO₂) and peak pulse oxygen was decreased in patients with OHS compared with patients with either obstructive sleep apnea or simple obesity. The ventilatory response to exertional metabolic demand (nadir VE/VCO₂, ∆VE/∆VCO₂ slope, and VE/VCO₂ at peak exercise) did not significantly differ among the 3 groups. Minute ventilation, tidal volume, respiratory frequency, tidal volume/respiratory frequency, and inspiratory time/total time ratio at a given work rate were comparable among the 3 groups. Among the whole cohort, apnea-hypopnea index was not independently associated with peak VO₂, and no association was found between the ∆VE/∆VCO₂ slope and resting arterial partial pressure of CO₂.

CONCLUSIONS

The ventilatory response to incremental exercise is preserved in patients with OHS compared with patients with obstructive sleep apnea and simple obesity who were matched for age and body mass index. This result highlights the complexity of the respiratory control system during exercise for patients with OHS, which may be uncoupled with the ventilatory response during sleep and resting conditions.

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.

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).

Hypercapnia at Hospital Admission as a Predictor of Mortality

Introduction

Hypercapnia is an indicator of ventilatory exhaustion. There is some disagreement regarding whether hypercapnia is also a predictor of mortality. In this prospective study, we aimed to investigate whether hypercapnia can predict in-hospital and 1-year mortality rates in patients with dyspnea or pulmonary diseases.

Patients and Methods

All patients with dyspnea or pulmonary diseases underwent routine blood gas analysis at hospital admission. During the 12-month enrollment period, 2710 patients were enrolled, and 588 patients with hypercapnia at admission were identified. Of the 1626 normocapnic patients, 62 were randomly selected as controls. In-hospital and 1-year mortality rates were determined.

Results

There were significant increases in mortality rate between acute hypercapnic patients and both chronic hypercapnic patients and normocapnic controls. Their in-hospital mortality rates were 17%, 6.7% and 3.2%, respectively. Their 1-year mortality rates were 32%, 20.2% and 14.5%, respectively. The 1-year mortality rates of hypercapnic patients with different underlying diseases were 24.6% (chronic obstructive pulmonary disease), 28.4% (congestive heart disease), 1.6% (obstructive sleep apnea syndrome/obesity hypoventilation syndrome), 50.9% (pneumonia), 0% (suppressed central respiratory drive, primarily due to opiate abuse) and 22.8% (other conditions).

Discussion

The 1-year mortality rate of patients with acute hypercapnia at hospital admission was 32%, with significant differences compared to chronic hypercapnic patients (20.2%) and normocapnic patients (14.5%). There was a wide range of 1-year mortality rates between the hypercapnic patients with different underlying diseases.

Validation of the Hungarian version of the SRI Questionnaire

BACKGROUND

Home mechanical ventilation is a reliable treatment for patients suffering from chronic respiratory failure, improving survival and quality of life. Prevalence has been increasing worldwide as a result of evolving technical possibilities, telemedicine and improving national guidelines. Projects to establish a national guideline and registry for patients treated with home mechanical ventilation are currently under way in Hungary and our aim was to validate a quality of life questionnaire suited for evaluation and follow up in this specific patient group. The Severe Respiratory Insufficiency Questionnaire (SRI) is a quality of life tool designed to evaluate patients receiving home mechanical ventilation and has been validated both in patient groups receiving invasive and noninvasive ventilation.

METHODS

The Hungarian version of the SRI was created using the translation-backtranslation method, which was then tested for validity, viability and reliability in a cohort involving patients from three centers, receiving long-term home mechanical ventilation for chronic respiratory failure through an invasive or noninvasive interface. Patient data was collected (demographic data, lung function test, arterial blood gas, ventilation settings) and quality of life was measured with the previously validated SF-36 and newly created Hungarian SRI Questionnaires at two time points.

RESULTS

One hundred four patients receiving home mechanical ventilation were enrolled. The time to complete the SRI Questionnaire was 8.6 (±3.1) minutes, 69.2% questionnaires were self-administered. Exploratory factor analysis explained 73.8% of the variance of the questionnaire, but resulted in 13 scales. We found correlations between the SRI subscale scores to corresponding scales of the previously validated general quality of life survey SF-36. The Cronbach alpha coefficient was 0.928 for the Summary Scale of the SRI Questionnaire, proving high internal consistency. Reproducibility was high for most scales, resulting in a high overall correlation for the summary score (0.877, p < 0.001).

CONCLUSIONS

The Hungarian version of the SRI Questionnaire is a viable, valid, reliable and reproduceable quality of life tool applicable for patients treated with home mechanical ventilation.

COPD Patients' Experience of Long-Term Domestic Oxygen-Enriched Nasal High Flow Treatment: A Qualitative Study

Little is known about chronic obstructive pulmonary disease (COPD) patients experience with home-based health treatments, which are currently rapidly evolving. A previous randomized controlled trial investigated the use of long-term oxygen enriched high flow nasal cannula (HFNC) treatment at home. The aim of this study was to explore COPD patients' experience using home HFNC treatment. Patients in this qualitative study were included from the previous RCT. All patients used long-term oxygen therapy and HFNC, the latter as a primarily nocturnal add-on. Data were collected using semi-structured interviews focused on four themes: 'Description of daily use', 'Experienced changes', 'Treatment benefits and disadvantages' and 'User-friendliness'. The interviewer played an encouraging, non-normative neutral facilitator role in order to give the participants possibility to explain themselves as fully as possible. Participants were recruited until themes were saturated. A total of 12 patients (5 males, 7 females) and 8 relatives participated. Six themes were identified as important to patient adherence: Perceived lower work of breathing; reduced symptoms; improved quality of sleep; increased activity of daily living; feeling safe; technology use. The results increase our knowledge of patient experience of using HFNC for home treatment, which improved the patients' experience through reducing symptoms and increase the activity of daily living. Furthermore, they substantiate the necessity of perceived usefulness and ease of use as important factors for adherence to treatment.

Validation of the Finnish severe respiratory insufficiency questionnaire

INTRODUCTION

Chronic respiratory insufficiency impacts patients' lives and reduces quality of life. The Severe Respiratory Insufficiency (SRI) questionnaire examines health-related quality of life and is designed specifically for patients receiving home mechanical ventilation (HMV) for chronic respiratory failure (CRF).

OBJECTIVES

The aim of this study was to validate the Finnish version of the SRI and study its reproducibility in patients with CRF.

METHODS

Our 74 patients receiving HMV or long-term oxygen treatment for CRF or both completed the SRI and St George's Respiratory questionnaires (SGRQ) three times (at baseline, and then one week and one month later). Reliability and validity of the questionnaires was analysed with Cronbach's alpha and intraclass correlation coefficient. Patients were prospectively followed up for 5 years, with data collected on their use of hospital services and mortality.

RESULTS

Cronbach's alpha in the SRI ranged from 0.67 to 0.88 and was >0.7 on all subscales except the "attendant symptoms and sleep". On four subscales, Cronbach's alpha was >0.8, and on the summary scale, 0.95. The SRI showed high correlation with SGRQ. Both tests showed good reproducibility. During the 5-year follow-up, 27 (36%) patients died.

CONCLUSIONS

The Finnish SRI proved valid, reliable and reproducible. Its psychometric properties were good and similar to those of the original questionnaire and of other validation studies.

Long-term non-invasive ventilation for stable chronic hypercapnic COPD

Introduction: Long-term non-invasive ventilation (LTNIV) for the stable hypercapnic chronic obstructive pulmonary disease (COPD)-patients have been a subject of much debate in the last two decades. The aim of this study was to compile the current knowledge on LTNIV in order to evaluate the effects on mortality and hypercapnia. Methods: Literature search in Pubmed, Ovid, and Embase for RCTs in Humans from January 2000 through January 2019 in written English. Results: Six studies with a total of 861 patients were included. LTNIV in stable hypercapnic COPD patients significantly reduced PaCO₂ but only one study found significant reduction in mortality. Conclusion: Our meta-analyses demonstrate that LTNIV significantly reduced PaCO₂ in stable patients with chronic hypercapnic respiratory failure compared to standard care alone, and subgroup analyses on studies with a predefined plan for ventilation, showed a considerable trend towards significant reduction in mortality. The take home messages on LTNIV in stable hypercapnic COPD are: It is essential that the patients have stable chronic hypercapnia.The degree of stability can best be assessed after a minimum of 2 weeks following an acute hypercapnic respiratory failure (AHRF).It is important to ventilate the patient with the goal to reduce PaCO₂ by at least 20% or below 6.5 kPa.

Nasal high-flow versus noninvasive ventilation in patients with chronic hypercapnic COPD

Background

Despite the encouraging results of noninvasive ventilation (NIV) in chronic hypercapnic COPD patients, it is also evident that some patients do not tolerate NIV or do not benefit from it. We conducted a study in which COPD patients with stable, chronic hypercapnia were treated with NIV and nasal high-flow (NHF) to compare effectiveness.

Methods

In a multi-centered, randomized, controlled, cross-over design, patients received 6 weeks of NHF ventilation followed by 6 weeks of NIV ventilation or vice-versa (TIBICO) between 2011 and 2016. COPD patients with stable daytime hypercapnia (pCO₂≥50 mmHg) were recruited from 13 German centers. The primary endpoint was pCO₂ changes from baseline blood gas, lung function, quality of life (QoL), the 6 min walking test, and duration of device use were secondary endpoints.

Results

A total of 102 patients (mean±SD) age 65.3±9.3 years, 61% females, body mass index 23.1±4.8 kg/m², 90% GOLD D, pCO₂ 56.5±5.4 mmHg were randomized. PCO₂ levels decreased by 4.7% (n=94; full analysis set; 95% CI 1.8-7.5, P=0.002) using NHF and 7.1% (95% CI 4.1-10.1, P<0.001) from baseline using NIV (indistinguishable to intention-to-treat analysis). The difference of pCO₂ changes between the two devices was -1.4 mmHg (95% CI -3.1-0.4, P=0.12). Both devices had positive impact on blood gases and respiratory scores (St. George's Respiratory Questionnaire, Severe Respiratory Insufficiency Questionnaire).

Conclusions

NHF may constitute an alternative to NIV in COPD patients with stable chronic hypercapnia, eg, those not tolerating or rejecting NIV with respect to pCO₂ reduction and improvement in QoL.

Biomarkers and clinical outcomes in COPD: a systematic review and meta-analysis

BACKGROUND

Conventional measures to evaluate COPD may fail to capture systemic problems, particularly musculoskeletal weakness and cardiovascular disease. Identifying these manifestations and assessing their association with clinical outcomes (ie, mortality, exacerbation and COPD hospital admission) is of increasing clinical importance.

OBJECTIVE

To assess associations between 6 min walk distance (6MWD), heart rate, fibrinogen, C reactive protein (CRP), white cell count (WCC), interleukins 6 and 8 (IL-6 and IL-8), tumour necrosis factor-alpha, quadriceps maximum voluntary contraction, sniff nasal inspiratory pressure, short physical performance battery, pulse wave velocity, carotid intima-media thickness and augmentation index and clinical outcomes in patients with stable COPD.

METHODS

We systematically searched electronic databases (August 2018) and identified 61 studies, which were synthesised, including meta-analyses to estimate pooled HRs, following Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Shorter 6MWD and elevated heart rate, fibrinogen, CRP and WCC were associated with higher risk of mortality. Pooled HRs were 0.80 (95% CI 0.73 to 0.89) per 50 m longer 6MWD, 1.10 (95% CI 1.02 to 1.18) per 10 bpm higher heart rate, 3.13 (95% CI 2.14 to 4.57) per twofold increase in fibrinogen, 1.17 (95% CI 1.06 to 1.28) per twofold increase in CRP and 2.07 (95% CI 1.29 to 3.31) per twofold increase in WCC. Shorter 6MWD and elevated fibrinogen and CRP were associated with exacerbation, and shorter 6MWD, higher heart rate, CRP and IL-6 were associated with hospitalisation. Few studies examined associations with musculoskeletal measures.

CONCLUSION

Findings suggest 6MWD, heart rate, CRP, fibrinogen and WCC are associated with clinical outcomes in patients with stable COPD. Use of musculoskeletal measures to assess outcomes in patients with COPD requires further investigation.

TRIAL REGISTRATION NUMBER

CRD42016052075.

Health-related quality of life as predictor for mortality in patients treated with long-term mechanical ventilation

Background

The Severe Respiratory Insufficiency (SRI) questionnaire is a specific measure of health-related quality of life (HRQoL) in patients treated with long-term mechanical ventilation (LTMV). The aim of the present study was to examine whether SRI sum scores and related subscales are associated with mortality in LTMV patients.

Methods

The study included 112 LTMV patients (non-invasive and invasive) from the Norwegian LTMV registry in Western Norway from 2008 with follow-up in August 2014. SRI data were obtained through a postal questionnaire, whereas mortality data were obtained from the Norwegian Cause of Death Registry. The SRI questionnaire contains 49 items and seven subscales added into a summary score (range 0–100) with higher scores indicating a better HRQoL. The association between the SRI score and mortality was estimated as hazard ratios (HRs) with 95% confidence intervals (95% CI) using Cox regression models and HRs were estimated per one unit change in the SRI score.

Results

Of the 112 participating patients in 2008, 52 (46%) had died by August 2014. The mortality rate was the highest in patients with chronic obstructive pulmonary disease (75%), followed by patients with neuromuscular disease (46%), obesity hypoventilation syndrome (31%) and chest wall disease (25%) (p < 0.001). Higher SRI sum scores in 2008 were associated with a lower mortality risk after adjustment for age, education, hours a day on LTMV, time since initiation of LTMV, disease category and comorbidity (HR 0.98, 95% CI: 0.96–0.99). In addition, SRI-Physical Functioning (HR 0.98, 95% CI: 0.96–0.99), SRI-Psychological Well-Being (HR 0.98, 95% CI: 0.97–0.99), and SRI-Social Functioning (HR 0.98, 95% CI: 0.97–0.99) remained significant risk factors for mortality after covariate adjustment. In the subgroup analyses of patient with neuromuscular diseases we found significant inverse associations between some of the SRI subscales and mortality.

Conclusions

SRI score is associated with mortality in LTMV-treated patients. We propose the use of SRI in the daily clinic with repeated measurements as part of individual follow-up. Randomized clinical trials with interventions aimed to improve HRQoL in LTMV patients should consider the SRI questionnaire as the standard HRQoL measurement.

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0768-4) contains supplementary material, which is available to authorized users.

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.

Long-term effects of oxygen-enriched high-flow nasal cannula treatment in COPD patients with chronic hypoxemic respiratory failure

BACKGROUND

This study investigated the long-term effects of humidified high-flow nasal cannula (HFNC) in COPD patients with chronic hypoxemic respiratory failure treated with long-term oxygen therapy (LTOT).

PATIENTS AND METHODS

A total of 200 patients were randomized into usual care ± HFNC. At inclusion, acute exacerbation of COPD (AECOPD) and hospital admissions 1 year before inclusion, modified Medical Research Council (mMRC) score, St George's Respiratory Questionnaire (SGRQ), forced expiratory volume in 1 second (FEV1), 6-minute walk test (6MWT) and arterial carbon dioxide (PaCO2) were recorded. Patients completed phone interviews at 1, 3 and 9 months assessing mMRC score and AECOPD since the last contact. At on-site visits (6 and 12 months), mMRC, number of AECOPD since last contact and SGRQ were registered and FEV1, FEV1%, PaCO2 and, at 12 months, 6MWT were reassessed. Hospital admissions during the study period were obtained from hospital records. Hours of the use of HFNC were retrieved from the high-flow device.

RESULTS

The average daily use of HFNC was 6 hours/day. The HFNC group had a lower AECOPD rate (3.12 versus 4.95/patient/year, p<0.001). Modeled hospital admission rates were 0.79 versus 1.39/patient/year for 12- versus 1-month use of HFNC, respectively (p<0.001). The HFNC group had improved mMRC scores from 3 months onward (p<0.001) and improved SGRQ at 6 and 12 months (p=0.002, p=0.033) and PaCO2 (p=0.005) and 6MWT (p=0.005) at 12 months. There was no difference in all-cause mortality.

CONCLUSION

HFNC treatment reduced AECOPD, hospital admissions and symptoms in COPD patients with hypoxic failure.

Factors associated with change in health-related quality of life among individuals treated with long-term mechanical ventilation, a 6-year follow-up study

AIMS

To examine changes and explanatory variables for changes in health-related quality of life in patients treated with long-term mechanical ventilation over a 6-year period.

BACKGROUND

Long-term mechanical ventilation is a treatment for individuals with chronic hypercapnic respiratory failure, primarily caused by neuromuscular diseases, obesity hypoventilation syndrome, chronic obstructive pulmonary and restrictive thoracic diseases. Studies on long-term outcome on health-related quality of life and factors influencing it are lacking.

DESIGN

Prospective cohort study.

METHODS

Data were collected from the Norwegian Long-Term-Mechanical-Ventilation Registry and from patient-reported questionnaire in 2008 and 2014. Health-related quality of life was measured by the Severe Respiratory Insufficiency questionnaire, containing 49 items and seven subdomains. Linear mixed effects models were used to measure changes and identify factors for changes.

RESULTS

After 6 years, 60 patients were still participating, out of 127 at baseline. Health-related quality of life improved significantly in the total score and in four subdomains of the questionnaire. Satisfaction with training in long-term mechanical ventilation was an explanatory variable for improved 'psychological well-being' and follow-up for improvement of 'anxiety'. Side effects of the treatment like facial soreness were associated with the total score. High age and high forced vital capacity were related to lower 'physical function' and improved 'social functioning', respectively.

CONCLUSION

Long-term mechanical ventilation over 6 years improved health-related quality of life in most patients. Patient training, follow-up and reduction of side effects, largely delivered by trained nurses, contribute to achieve the main goal of the treatment-improved health-related quality of life.

Validation of the Greek version of the Severe Respiratory Insufficiency questionnaire

BACKGROUND

The Severe Respiratory Insufficiency (SRI) questionnaire is a multidimensional, well-validated tool for the assessment of health-related quality of life (HRQL) in patients with severe chronic respiratory failure (CRF), due to a variety of underlying disorders. The aim of this study was to validate the SRI questionnaire in the Greek language (Gr-SRI).

METHODS

Reliability and validity analyses were performed for the Gr-SRI using data of 136 consecutive patients with CRF, due to chronic obstructive pulmonary disease (COPD) or non-COPD respiratory diseases (kyphoscoliosis, obesity-hypoventilation, and post-tuberculosis sequelae). Sixty-three patients (46.3 %) were under long-term oxygen therapy (LTOT), while 73 (53.7 %) under long-term non-invasive mechanical ventilation at home (HMV), either with or without LTOT.

RESULTS

Cronbach's alpha was high for the Summary Score of the SRI (0.86) showing high internal consistency, comparable to that of the original German version. The results of the principal component analysis on the SRI Summary Score produced a one-factor construct with a variance of 54 %, which confirmed a single Summary Score for the Greek SRI also. The highest and the lowest scores were detected in Respiratory Complaints and Physical Functioning subscales, respectively. The SRI was capable of discriminating COPD patients and non-COPD patients, with COPD patients having lower mean SRI scores, but no difference was observed between COPD patients under HMV or LTOT.

CONCLUSIONS

Greek SRI has high psychometric properties qualifying its use for HRQL assessment in patients with CRF. HIPPOKRATIA 2017, 21(4): 186-190.

Comorbidities and Subgroups of Patients Surviving Severe Acute Hypercapnic Respiratory Failure in the Intensive Care Unit

RATIONALE

No methodical assessment of the lung, cardiac, and sleep function of patients surviving an acute hypercapnic respiratory failure episode requiring admission to the intensive care unit (ICU) has been reported in the literature.

OBJECTIVES

To prospectively investigate the prevalence and impact of comorbidities in patients treated by mechanical ventilator support (invasive or noninvasive) for acute hypercapnic respiratory failure in the ICU.

METHODS

Seventy-eight consecutive patients admitted for an episode of acute hypercapnic respiratory failure underwent an assessment of lung, cardiac, and sleep function by pulmonary function tests, transthoracic echocardiography, and polysomnography 3 months after ICU discharge.

MEASUREMENTS AND MAIN RESULTS

Sixty-seven percent (52 of 78) of patients exhibited chronic obstructive pulmonary disease (COPD), although only 19 had been previously diagnosed. Patients without COPD were primarily obese. Prevalence of severe obstructive sleep apnea was 51% (95% confidence interval, 34-69) in patients with COPD and 81% (95% confidence interval, 54-96) in patients without COPD. Previously undiagnosed cardiac dysfunction with preserved ejection fraction was highly prevalent (44%), as was hypertension (67%). More than half of the population demonstrated at least three major comorbidities known to precipitate acute hypercapnic respiratory failure. Multimorbidity was associated with longer time to hospital discharge. Hospital readmission or death occurred in 46% of patients over an average of 3.5 months after discharge.

CONCLUSIONS

Severe hypercapnic respiratory failure requiring ICU admission resulted primarily from COPD or obesity. Major comorbidities are highly prevalent in both cases and most often ignored. Surviving acute hypercapnic respiratory failure should be an opportunity to systematically evaluate lung, heart, and sleep functions to improve poor outcomes. Clinical trial registered with www.clinicaltrials.gov (NCT 02111876).

Survival of Hypercapnic Patients with COPD and Obesity Hypoventilation Syndrome Treated with High Intensity Non Invasive Ventilation in the Daily Routine Care

BACKGROUND

Home ventilation is an effective treatment option for obesity hypoventilation syndrome (OHS). This therapy is still controversial for stable chronic obstructive pulmonary disease (COPD). A recent study showed reduced mortality for COPD patients receiving home ventilation with high inflation pressures and back-up respiratory rates [so called High Intensity non-invasive ventilation (NIV)].

OBJECTIVE

The purpose of this study is whether High Intensity NIV applied in the routine care of COPD and OHS patients can lead to CO2 reduction and survival data comparable to data from controlled studies.

METHOD

In this prospective non interventional study fifty-one patients with COPD (FEV1 0.95l, corr. 32.8%) and 34 patients with OHS (VC 1.74l, corr. 50.7%) with chronic hypercapnic respiratory failure, who were treated with NIV were followed up for four years.

RESULTS

Elevated CO2 values before NIV in COPD patients (8.6kPa), and in OHS patients (8.3kPa), could be lowered significantly to the upper normal range (COPD: 5.9kPa; OHS: 5.85kPa). The one-, two-, and three-year survival rates for COPD patients were 83%, 73%, and 55%, respectively. The one-, two-, and three-year survival rates for OHS patients were 85%, 72%, and 68%, respectively.

CONCLUSION

High intensity NIV within routine care is effective in reducing blood CO2 levels in COPD- and in OHS- related chronic respiratory insufficiency. The survival rates obtained here are comparable to data from controlled clinical trials on COPD.

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.

Evaluation of Health-Related Quality of Life among Tuberculosis Patients in Two Cities in Yemen

Background

The health-related quality of life (HRQoL) of Tuberculosis (TB) patients is important because it directly influences the outcome of TB patients in several aspects. The current study aims to evaluate and to find the factors influencing the HRQoL of TB patients in two major TB-prevalent cities (Taiz and Alhodidah) in Yemen.

Methods

A prospective study was conducted, and all TB patients meeting the HRQoL criteria were asked to complete the HRQoL SF-36 survey. The records of TB patients were examined for disease confirmation, and a follow-up was consequently performed for patients during treatment between March 2013 and February 2014 in Taiz and Alhodidah Cities. HRQol scores were calculated by using QM scoring software version 4.5, in which the physical component score (PCS) and mental component score (MCS) were obtained. The scores obtained between 47–53 normal based score (NBS) were considered equivalent to the US normal score. Low scores indicate the poor health situation of TB patients

Results

A total of 243 TB patients enrolled in the study at the beginning of the treatment. A total of 235 and 197 TB patients completed the questionnaire at the end of the intensive phase (I.P.) and continuation phase (C.P.), respectively. The final dropout rate was 16.2%. The mean PCS and MCS scores at the beginning of treatment were low, thus showing the poor health situation of TB patients. The mean PCS scores at the beginning of treatment, end of I.P., and end of treatment were (36.1), (44.9), and (48), respectively. Moreover, the mean MCS score at the beginning of treatment, end of I.P., and end of treatment were (35.1), (42.2), and (44.3), respectively. The result shows that significant increases are observed at the end of I.P. for PCS and MCS because of the treatment and slight changes at the end of C.P. Despite this finding, the MCS score remains below the normal range (47), thus indicating a significant risk of depression among TB patients. Furthermore, general linear repeated measure ANOVA was performed for selected variables, to examine the changes of PCS and MCS over time. It was found that Alhodiah city, chewing khat habit, stigmatization, and duration of treatment more than six months were greatly associated with low mean MCS score of TB patient, indicating great risk of depression which may result in poor treatment outcome.

Conclusion

TB patients in Yemen were found to have poor QoL, with a significant likelihood of depression. Highly risk depression was found among TB patients in Alhodiah city, khat chewers, stigmatization and having a duration of treatment more than 6 months. Therefore, additional efforts should be made to improve their QoL because it may affect the final clinical outcome of patients.

Clinical Outcomes Associated with Home Mechanical Ventilation: A Systematic Review

Background. The prevalence of patients supported with home mechanical ventilation (HMV) for chronic respiratory failure has increased. However, the clinical outcomes associated with HMV are largely unknown. Methods. We performed a systematic review of studies evaluating patients receiving HMV for indications other than obstructive lung disease, reporting at least one clinically relevant outcome including health-related quality of life (HRQL) measured by validated tools; hospitalization requirements; caregiver burden; and health service utilization. We searched MEDLINE, EMBASE, CINAHL, the Cochrane library, clinical trial registries, proceedings from selected scientific meetings, and bibliographies of retrieved citations. Results. We included 1 randomized control trial (RCT) and 25 observational studies of mixed methodological quality involving 4425 patients; neuromuscular disorders (NMD) (n = 1687); restrictive thoracic diseases (RTD) (n = 481); obesity hypoventilation syndrome (OHS) (n = 293); and others (n = 748). HRQL was generally described as good for HMV users. Mental rather than physical HRQL domains were rated higher, particularly where physical assessment was limited. Hospitalization rates and days in hospital appear to decrease with implementation of HMV. Caregiver burden associated with HMV was generally high; however, it is poorly described. Conclusion. HRQL and need for hospitalization may improve after establishment of HMV. These inferences are based on relatively few studies of marked heterogeneity and variable quality.

Mental health, serum biomarkers and survival in severe COPD: a pilot study

Background

Chronic obstructive pulmonary disease (COPD) impairs physical status and impacts on mental health. This prospective study was designed to assess associations between mental health and systemic biomarkers, and their combined relationship with long-term survival in stable severe COPD.

Methods

Forty-five patients with severe but stable COPD (forced expiratory volume in 1 s of 29.8 (quartiles: 22.6; 41.4) %predicted) were assessed using the Hospital Anxiety and Depression Scale (HADS), the Patient Health Questionnaire (PHQ), St. George’s Respiratory Questionnaire and the State-Trait Anxiety Inventory (STAI). The following serum biomarkers were measured: 25-OH-cholecalciferol, C-reactive protein, erythrocyte sedimentation rate, leucocyte number, serum amyloid-A (SA-A), N-terminal pro-brain natriuretic peptide, troponin I, glycosylated haemoglobin, haemoglobin (Hb), haematocrit (Hc), creatinine and thyroid-stimulating hormone. Patients were followed-up for 36 months. Associations between aspects of mental health and biomarkers, and their utility as predictors of 3-year survival were evaluated by regression analyses.

Results

The prevalence of anxiety (HADS-A: 89.9 %), depression (HADS-D: 58.8 %; PHQ: 60.6 %), somatisation (PHQ-15: 81.8 %) and psychosocial stress (PHQ-stress: 60.6 %) was high. There was a significant positive association between the leucocyte count and SA-A level with STAI-trait anxiety (p = 0.03 and p = 0.005, respectively), and between leucocytes and PHQ-stress (p = 0.043). Hb and Hc were significantly negatively associated with HADS-depression (p = 0.041 and p = 0.031, respectively). Univariate Cox regression analyses revealed that leucocyte count (hazard ratio (HR) 2.976, 95 % CI 1.059-8.358; p = 0.038), and stress (HR 4.922, 95 % CI 1.06–22.848; p = 0.042) were linked to long-term survival. In multivariate Cox regression analyses, including known risk factors for survival in COPD, PHQ-stress (HR 45.63, 95 % CI 1.72–1,208.48; p = 0.022) remained significantly associated with survival.

Conclusion

In this pilot study different dimensions of mental health were correlated to serum biomarkers, probably reflecting systemic effects of COPD. While leucocyte number and PHQ-stress were associated with long-term survival in univariate analyses, PHQ-stress remained in multivariate analyses as independent prognostic factor.

Is hypercapnia associated with poor prognosis in chronic obstructive pulmonary disease? A long-term follow-up cohort study

OBJECTIVES

To assess whether hypercapnia may predict the prognosis in chronic obstructive pulmonary disease (COPD).

DESIGN

Prospective cohort study comparing the survival of patients with COPD and normocapnia to those with chronic hypercapnia.

SETTING

Patients with consecutive COPD were enrolled between 1 May 1993 and 31 October 2006 at two medical centres. Follow-up was censored on 31 October 2011.

PARTICIPANTS

A total of 275 patients with stable COPD and aged 40-85 years were enrolled. Diagnosis of hypercapnia was confirmed by blood gas analysis. Patients with near-terminal illness or comorbidities that affect PaCO2 (obstructive sleep apnoea, obesity-related hypoventilation, or neuromuscular disease) were excluded. The outcome of 98 patients with normocapnia and 177 with chronic hypercapnia was analysed.

OUTCOME MEASURES

Overall survival.

RESULTS

Median survival was longer in patients with normocapnia than in those with hypercapnia (6.5 vs 5.0 years, p=0.016). Multivariate COX regression analysis indicated that age (HR=1.043, 95% CI 1.012 to 1.076), Charlson Index, which is a measure of comorbidity (HR=1.172, 95% CI 1.067 to 1.288), use of medication (HR=0.565, 95% CI 0.379 to 0.842), body mass index (BMI) (HR=0.922, 95% CI 0.883 to 0.963), PaCO2 (HR=1.026, 95% CI 1.011 to 1.042), Cor pulmonale (HR=2.164, 95% CI 1.557 to 3.006), non-invasive positive-pressure ventilation (NPPV) (HR=0.615, 95% CI 0.429 to 0.881) and per cent of forced expiratory volume in 1 s (FEV1%) (HR=0.979, 95% CI 0.967 to 0.991), were independent risk factors for mortality.

CONCLUSIONS

Increased age, Charlson Index, chronic hypercapnia and Cor pulmonale, and decreased FEV1%, use of medication, BMI and NPPV, were associated with a poor prognosis in patients with COPD.

Acute cardiopulmonary failure from sleep-disordered breathing

Sleep-disordered breathing (SDB) comprises a diverse set of disorders marked by abnormal respiration during sleep. Clinicians should realize that SDB may present as acute cardiopulmonary failure in susceptible patients. In this review, we discuss three clinical phenotypes of acute cardiopulmonary failure from SDB: acute ventilatory failure, acute congestive heart failure, and sudden death. We review the pathophysiologic mechanisms and recommend general principles for management. Timely recognition of, and therapy for, SDB in the setting of acute cardiopulmonary failure may improve short- and long-term outcomes.

Self-perceived quality of life predicts mortality risk better than a multi-biomarker panel, but the combination of both does best

Background

Associations between measures of subjective health and mortality risk have previously been shown. We assessed the impact and comparative predictive performance of a multi-biomarker panel on this association.

Methods

Data from 4,261 individuals aged 20-79 years recruited for the population-based Study of Health in Pomerania was used. During an average 9.7 year follow-up, 456 deaths (10.7%) occurred. Subjective health was assessed by SF-12 derived physical (PCS-12) and mental component summaries (MCS-12), and a single-item self-rated health (SRH) question. We implemented Cox proportional-hazards regression models to investigate the association of subjective health with mortality and to assess the impact of a combination of 10 biomarkers on this association. Variable selection procedures were used to identify a parsimonious set of subjective health measures and biomarkers, whose predictive ability was compared using receiver operating characteristic (ROC) curves, C-statistics, and reclassification methods.

Results

In age- and gender-adjusted Cox models, poor SRH (hazard ratio (HR), 2.07; 95% CI, 1.34-3.20) and low PCS-12 scores (lowest vs. highest quartile: HR, 1.75; 95% CI, 1.31-2.33) were significantly associated with increased risk of all-cause mortality; an association independent of various covariates and biomarkers. Furthermore, selected subjective health measures yielded a significantly higher C-statistic (0.883) compared to the selected biomarker panel (0.872), whereas a combined assessment showed the highest C-statistic (0.887) with a highly significant integrated discrimination improvement of 1.5% (p < 0.01).

Conclusion

Adding biomarker information did not affect the association of subjective health measures with mortality, but significantly improved risk stratification. Thus, a combined assessment of self-reported subjective health and measured biomarkers may be useful to identify high-risk individuals for intensified monitoring.

Obesity hypoventilation syndrome: mechanisms and management

Obesity hypoventilation syndrome describes the association between obesity and the development of chronic daytime alveolar hypoventilation. This syndrome arises from a complex interaction between sleep-disordered breathing, diminished respiratory drive, and obesity-related respiratory impairment, and is associated with significant morbidity and mortality. Therapy directed toward reversing these abnormalities leads to improved daytime breathing, with available treatment options including positive pressure therapy, weight loss, and pharmacological management. However, a lack of large-scale, well-designed studies evaluating these various therapies has limited the development of evidence-based treatment recommendations. Although treatment directed toward improving sleep-disordered breathing is usually effective, not all patients tolerate mask ventilation and awake hypercapnia may persist despite effective use. In the longer term, weight loss is desirable, but data on the success and sustainability of this approach in obesity hypoventilation are lacking. The review outlines the major mechanisms believed to underlie the development of hypoventilation in this subgroup of obese patients, their clinical presentation, and current therapy options.

Associations between mortality, asthma, and health-related quality of life in an elderly cohort of Swedes

BACKGROUND

Asthma is a common chronic health condition among the elderly and an important cause of morbidity and mortality. Some studies show that subjective assessments of health-related quality of life (HRQL) are important predictors of mortality and survival. The primary aim of this study was to investigate whether low HRQL was a predictor of mortality in elderly subjects and whether such an association differed between subjects with and without asthma.

METHODS

In 1990, a cohort in middle Sweden was investigated using a respiratory questionnaire. To assess HRQL, the generic instrument Gothenburg Quality of Life (GQL) was used. The participants were also investigated by spirometry and allergy testing. The present study was limited to the subjects in the oldest age group, aged 60-69 years in 1990, and included 222 subjects with clinically verified asthma, 148 subjects with respiratory symptoms but no asthma or other lung diseases, and 102 subjects with no respiratory symptoms. Mortality in the cohort was followed during 1990-2008.

RESULTS

Altogether, 166 of the 472 subjects in the original cohort had died during the follow-up period of 1990-2008. Mortality was significantly higher in men, in older subjects, in smokers, and subjects with a low forced expiratory volume in one second (FEV(1)). There was, however, no difference in mortality between the asthmatic and the nonasthmatic groups. A higher symptoms score for GQL was significantly related to increased mortality. No association between HRQL and mortality was found when limiting the analysis to the asthmatic group, although the asthmatics had a lower symptom score for GQL compared to the other groups.

CONCLUSION

A higher symptom score in the GQL instrument was significantly related to increased mortality, but this association was not found when analyzing the asthmatic group alone. The negative prognostic implications of a low HRQL in the whole group and the fact that the asthmatic group had a lower HRQL than the other group supports the use of HRQL instruments in clinical health assessments.

The pickwickian syndrome-obesity hypoventilation syndrome

Obesity-hypoventilation syndrome (OHS), also historically described as the Pickwickian syndrome, consists of the triad of obesity, sleep disordered breathing, and chronic hypercapnia during wakefulness in the absence of other known causes of hypercapnia. Its exact prevalence is unknown, but it has been estimated that 10% to 20% of obese patients with obstructive sleep apnea have hypercapnia. OHS often remains undiagnosed until late in the course of the disease. Early recognition is important because these patients have significant morbidity and mortality. Effective treatment can lead to significant improvement in patient outcomes, underscoring the importance of early diagnosis. The authors review the definition and epidemiology of OHS, in addition to the current multifaceted understanding of the pathophysiology, and provide useful clinical approaches to diagnosis and treatment.

Treatment of respiratory failure in COPD

Patients with advanced COPD and acute or chronic respiratory failure are at high risk for death. Beyond pharmacological treatment, supplemental oxygen and mechanical ventilation are major treatment options. This review describes the physiological concepts underlying respiratory failure and its therapy, as well as important treatment outcomes. The rationale for the controlled supply of oxygen in acute hypoxic respiratory failure is undisputed. There is also a clear survival benefit from long-term oxygen therapy in patients with chronic hypoxia, while in mild, nocturnal, or exercise-induced hypoxemia such long-term benefits appear questionable. Furthermore, much evidence supports the use of non-invasive positive pressure ventilation in acute hypercapnic respiratory failure. It application reduces intubation and mortality rates, and the duration of intensive care unit or hospital stays, particularly in the presence of mild to moderate respiratory acidosis. COPD with chronic hypercapnic respiratory failure became a major indication for domiciliary mechanical ventilation, based on pathophysiological reasoning and on data regarding symptoms and quality of life. Still, however, its relevance for long-term survival has to be substantiated in prospective controlled studies. Such studies might preferentially recruit patients with repeated hypercapnic decompensation or a high risk for death, while ensuring effective ventilation and the patients’ adherence to therapy.

[Clinical value of forced expiratory volume in 1 s (FEV1) in chronic obstructive pulmonary disease]

There is overwhelming evidence from large-scale placebo-controlled trials but also from epidemiologic COPD (chronic obstructive pulmonary disease) studies and meta-analyses supporting FEV(1) (forced expiratory volume in 1 s) as a strong diagnostic and prognostic marker that predicts future morbidity and mortality. Specifically, attenuation of reduced FEV(1) is a powerful indicator of successful medical intervention and vice versa. FEV(1) decline indicates an increasing risk for advanced disease stage eventually leading to further deterioration. However, it remains to be determined whether reducing the frequency of exacerbations or pharmacological improvement of FEV(1) can help to slow lung function decline and consequently improve clinical outcome in these patients. All in all, FEV(1) and its change over time are essential parameters in the assessment of COPD progression and efficacy of therapeutic intervention.