Noninvasive ventilation in stable hypercapnic COPD: what is the evidence?

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

BACKGROUND

Noninvasive ventilation (NIV) is recommended as the first-line respiratory support method for patients with hypercapnic respiratory failure (HRF). However, the need for well-trained operators and the occurrence of treatment discomfort may limit its efficacy. High-flow nasal oxygen therapy (HFNO) is a convenient respiratory support with user-friendly operation, high comfort, and good compliance. This systematic review and meta-analysis was performed to compare the therapeutic effects of HFNO and other noninvasive respiratory support methods [NIV or conventional oxygen therapy (COT)] in patients with acute HRF (AHRF) or chronic HRF (CHRF).

METHODS

We searched the PubMed, Web of Science, Embase, and Cochrane Library databases from inception to May 2024 to identify randomized clinical trials comparing the impact of HFNO and NIV/COT in adults with HRF.

RESULTS

Sixteen studies (1630 patients) were included. Compared with NIV, HFNO did not improve the primary outcome of PaCO2 in patients with AHRF or CHRF [AHRF: MD = -0.81, 95 % CI = -3.40 to 1.77; CHRF: MD = 1.82, 95 % CI = 0.44 to 3.20]. However, HFNO showed advantages over COT (AHRF: MD = -2.03, 95 % CI = -3.48 to -0.59; CHRF: MD = -2.64, 95 % CI = -4.24 to -1.03).

CONCLUSIONS

The evidence of its clinical efficacy in hypercapnic patients remains inconclusive. Further studies are needed to generate more evidence for the application of HFNO in patients with HRF and to determine the subset of patients for whom may be preferable.

Initiation of home noninvasive ventilation in hypercapnic chronic obstructive pulmonary disease: when, where, and how?

PURPOSE OF REVIEW

This review aims to highlight the importance of timely initiation of home noninvasive ventilation (homeNIV) for patients with chronic hypercapnic respiratory failure (CHRF) due to chronic obstructive pulmonary disease (COPD). As emerging evidence continues to show substantial benefits in reducing mortality and hospitalizations, it's crucial to identify which patients will benefit most and to provide clear guidance on implementing homeNIV effectively.

RECENT FINDINGS

Recent research supports the use of high intensity homeNIV for CHRF secondary to COPD, showing marked reductions in hospitalizations and mortality. However, despite its proven benefits, homeNIV is underutilized, often due to significant barriers related to payor policies and gaps in knowledge by those most likely to be evaluating and managing patients with advanced COPD. The literature also reveals ongoing debate about the optimal timing and setting for starting homeNIV, whether in outpatient clinics or directly after hospital discharge.

SUMMARY

The evidence suggests that homeNIV should be more widely used, with a focus on early initiation and careful titration to normalize PaCO 2 over time. By addressing the barriers to its broader use, we can improve outcomes for patients with CHRF due to COPD.

Sleep Deficiency, Sleep Apnea, and Chronic Lung Disease

With sleep occupying up to one-third of every adult's life, addressing sleep is essential to overall health. Sleep disturbance and deficiency are common in patients with chronic lung diseases and associated with worse clinical outcomes and poor quality of life. A detailed history incorporating nocturnal respiratory symptoms, symptoms of obstructive sleep apnea (OSA) and restless legs syndrome, symptoms of anxiety and depression, and medications is the first step in identifying and addressing the multiple factors often contributing to sleep deficiency in chronic lung disease. Additional research is needed to better understand the relationship between sleep deficiency and the spectrum of chronic lung diseases.

Defining a phenotype of severe COPD patients who develop chronic hypercapnia

INTRODUCTION

Chronic hypercapnia, defined by elevated blood CO2 levels, is a serious complication most prevalent in severe COPD. It negatively impacts quality of life, increases hospitalization rates, and elevates mortality risks. However, not all severe COPD patients develop chronic hypercapnia, and its underlying mechanisms remain unclear. Identifying clinical and pathophysiological predictors of hypercapnia is essential for tailored treatment strategies. This study investigates the relationship between hypercapnia and patient characteristics, lung function, and CT scan features to identify potential therapeutic targets.

METHODS

This cross-sectional study included 1526 COPD patients from three cohorts: a standard care cohort and two research cohorts (NCT04023409; NCT03053973). Data collected included demographic and clinical information, blood gases, lung function (FEV1, FVC, TLC, RV, DLCOc), and high-resolution CT scans (lung volumes, air trapping, emphysema scores, airway wall thickness (Pi10), and diaphragm indices).

RESULTS

Hypercapnia prevalence increased with COPD severity. Hypercapnic patients were older, more likely to smoke, and had more comorbidities. They exhibited lower FEV1 and FVC, and higher RV/TLC ratios, with CT scans showing lower emphysema scores and greater Pi10. Multivariate analysis identified lower PaO2, FEV1% predicted, and emphysema scores, along with higher RV/TLC ratios and NT-proBNP levels, as independent predictors of PaCO2, collectively explaining 46.3 % of the variance.

CONCLUSION

COPD patients with chronic hypercapnia are characterized by higher smoking rates, lower PaO2 levels, poorer lung function, less emphysema, and increased airway pathology. These findings underscore the multifactorial nature of hypercapnia in COPD, highlighting the need for personalized therapeutic strategies targeting these factors to improve outcomes.

Chronic obstructive pulmonary disease (COPD) and COPD-like phenotypes

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease. Historically, two COPD phenotypes have been described: chronic bronchitis and emphysema. Although these phenotypes may provide additional characterization of the pathophysiology of the disease, they are not extensive enough to reflect the heterogeneity of COPD and do not provide granular categorization that indicates specific treatment, perhaps with the exception of adding inhaled glucocorticoids (ICS) in patients with chronic bronchitis. In this review, we describe COPD phenotypes that provide prognostication and/or indicate specific treatment. We also describe COPD-like phenotypes that do not necessarily meet the current diagnostic criteria for COPD but provide additional prognostication and may be the targets for future clinical trials.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Effect of Intensity of Home Noninvasive Ventilation in Individuals With Neuromuscular and Chest Wall Disorders: A Systematic Review and Meta-Analysis of Individual Participant Data

INTRODUCTION

Home noninvasive ventilation (NIV), targeting a reduction of carbon dioxide with a combination of sufficient inspiratory support and backup-rate improves outcomes in patients with chronic obstructive pulmonary disease. The aim of this systematic review with individual participant data (IPD) meta-analysis was to evaluate the effects of intensity of home NIV on respiratory outcomes in individuals with slowly progressive neuromuscular (NMD) or chest-wall disorders (CWD).

METHODS

Controlled, non-controlled and cohort studies indexed between January-2000 and December-2020 were sought from Medline, Embase and the Cochrane Central Register. Outcomes were diurnal PaCO₂, PaO₂, daily NIV usage, and interface type (PROSPERO-CRD 42021245121). NIV intensity was defined according to the Z-score of the product of pressure support (or tidal volume) and backup-rate.

RESULTS

16 eligible studies were identified; we obtained IPD for 7 studies (176 participants: 113-NMD; 63-CWD). The reduction in PaCO₂ was greater with higher baseline PaCO₂. NIV intensity per se was not associated with improved PaCO₂ except in individuals with CWD and the most severe baseline hypercapnia. Similar results were found for PaO₂. Daily NIV usage was associated with improvement in gas exchange but not with NIV intensity. No association between NIV intensity and interface type was found.

CONCLUSION

Following home NIV initiation in NMD or CWD patients, no relationship was observed between NIV intensity and PaCO₂, except in individuals with the most severe CWD. The amount of daily NIV usage, rather than intensity, is key to improving hypoventilation in this population during the first few months after introduction of therapy.

Application of Acupoint Catgut Embedding Therapy Combined with Liuzijue Breathing Exercise in the Treatment of Patients with Stable Chronic Obstructive Pulmonary Disease

Objective

To evaluate the application value of acupoint catgut embedding therapy combined with Liuzijue breathing exercise in the treatment of patients with stable chronic obstructive pulmonary disease (COPD) and its impact on immune function and quality of life.

Methods

A total of 100 patients with stable COPD admitted to our hospital from February 2020 to February 2021 were included and assigned to the experimental group (n = 50) and the control group (n = 50) according to the order of admission. Both groups of patients received conventional treatment. The control group was given daily inhalation of budesonide and formoterol fumarate powder for inhalation (320 ug/bottle), and the experimental group received additional acupoint catgut embedding therapy combined with Liuzijue breathing exercise. The clinical efficacy, pulmonary function indexes, activities of daily living (ADL) scores, quality of life (QOL) scores, traditional Chinese medicine (TCM) syndrome scores, the number of acute exacerbations, medical expenses, the incidence of adverse reactions, and immune indicators were compared between the two groups of patients.

Results

The experimental group yielded a significantly higher effective rate of treatment than the control group (P < 0.05). After the treatment, the experimental group obtained a superior outcome in terms of lung function indexes, immune function indexes, ADL and QOL scores, and the TCM syndrome scores when compared with the control group (P < 0.05). The number of acute exacerbations in the experimental group was remarkably lower than that in the control group (P < 0.05). No serious adverse reactions were observed in the two groups of patients, and no significant difference in the incidence of adverse reactions was found (P > 0.05).

Conclusion

Acupoint catgut embedding therapy combined with Liuzijue breathing exercise, with high safety, can improve the treatment effect and the quality of life of patients with stable COPD, which merits clinical promotion.

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

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

Sleep Deficiency, Sleep Apnea, and Chronic Lung Disease

With sleep occupying up to one-third of every adult's life, addressing sleep is essential to overall health. Sleep disturbance and deficiency are common in patients with chronic lung diseases and associated with worse clinical outcomes and poor quality of life. A detailed history incorporating nocturnal respiratory symptoms, symptoms of obstructive sleep apnea (OSA) and restless legs syndrome, symptoms of anxiety and depression, and medications is the first step in identifying and addressing the multiple factors often contributing to sleep deficiency in chronic lung disease. Additional research is needed to better understand the relationship between sleep deficiency and the spectrum of chronic lung diseases.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

Supplementary Information

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

Effect of neuromuscular electrical stimulation on exercise capacity in patients with severe chronic obstructive pulmonary disease: A randomised controlled trial

OBJECTIVE

To compare strengthening by neuromuscular electrical stimulation versus cycle ergometer training during a pulmonary rehabilitation program, in patients with severe to very severe chronic obstructive pulmonary disease.

DESIGN

A prospective randomized controlled study.

SETTING

Two inpatient pulmonary rehabilitation centers.

SUBJECTS

Patients with severe to very severe chronic obstructive pulmonary disease and multidimensional index to predict risk of death ≥5, were randomly assigned to receive neuromuscular electrical stimulation or cycle ergometer training during pulmonary rehabilitation.

MAIN MEASURES

The primary endpoint was the change in exercise capacity using 1-min sit-to-stand test Secondary endpoints were the changes in exercise capacity using 6-min walk test, quadriceps strength, quality of life and dyspnea.

RESULTS

102 patients were included. After 3 weeks, 47 patients in the neuromuscular electrical stimulation group, and 45 in the cycle ergometer training group were able to be analyzed. No significant difference was seen in the evolution of exercise capacity using 1-min sit-to-stand test (3.3 ± 3.8 and 2.6 ± 4.1) and 6-min walk test (37.8 ± 58.4 and 33.1 ± 46.7), in the evolution of quadriceps strength and endurance (9.2 ± 12.9 and 6.6 ± 16.1; 9.0 ± 13.2 and 6.2 ± 17.0), in the evolution of quality of life (St George's Respiratory Questionnaire: -11.3 ± 11.7 and -8.1 ± 11.6; COPD Assessment Test: -5.7 ± 7.1 and -4.7 ± 7.0), or in the evolution of dyspnea using Dyspnea 12 (-5.5 ± 10.2 and -5.9 ± 8.5) except using modified medical research council scale (95% confidence interval: 0.48 [0.05; 0.91], p = 0.027).

CONCLUSION

We found no significant difference between the two programs on exercise capacity, quadriceps strength and quality of life.

“The role of a negative pressure ventilator coupled with oxygen helmet against COVID-19: a review”

Background

The coronavirus (SARS-COV-2) pandemic has provoked the global healthcare industry by potentially affecting more than 20 14 million people across the globe, causing lasting damage to the lungs, notably pneumonia, ARDS (acute respiratory distress 15 syndrome), and sepsis with the rapid spread of infection. To aid the functioning of the lungs and to maintain the blood oxygen 16 saturation (SpO₂) in coronavirus patients, ventilator assistance is required.

Materials and methods

The main purpose of this article is to outline the need 17 for the introduction of a non-invasive negative pressure ventilator (NINPV) as a promising alternative to positive pressure 18 ventilator (PPV) by elucidating the cons of non-invasive ventilators in clinical conditions like ARDS. Another motive is to 19 profoundly diminish the rate of infection spread by the employment of oxygen helmets, instead of endotracheal intubation in 20 invasive positive pressure ventilator (IPPV) or non-invasive positive pressure ventilator (NIPPV) like face masks and high-flow 21 nasal cannula (HFNC).

Result and conclusion

The integration of oxygen helmet with NPV would result in a number of notable facets including the 22 degree of comfort delivered to patients who are exposed to various ventilator-induced lung injuries (VILI) in the forms of 23 atelectasis, barotrauma, etc. Likewise, preventing the aerosol-generating procedures (AGP) diminishes the rate of nosocomial 24 infections and providing a better environment to both the patients and the healthcare professionals.

Stable Chronic Obstructive Pulmonary Disease (COPD) Management Under a Tiered Medical System in China

Background

Early diagnosis and proper management of a large number of chronic obstructive pulmonary disease (COPD) patients are great challenges for the Chinese health care system. Although tiered medical services have been promoted by the Chinese government since 2015, they have not been ideally implemented for COPD diagnosis and management.

Patients and Methods

We designed a cross-sectional study. Eligible COPD patients (n = 648) and physicians (n = 161) were consecutively recruited from 8 hospitals in different tiers in China. COPD characteristics and treatments were compared among hospitals in different tiers. Multivariate logistic regression was performed to identify risk factors associated with airflow limitation, symptoms and acute exacerbation.

Results

The PFT rate at first diagnosis was 99%, 69.4% and 29.9% in teaching, second-tier and community hospitals (P < 0.001). Only approximately 10.9%, 1.7% and 9.6% and 21.8%, 6.9% and 32% of COPD patients received influenza or pneumococcal vaccines (P < 0.001). The proportion of patients who did not use inhaled drugs or had irregular inhalation was 2%, 24.6% and 78.8% (P < 0.001). Education level (RR-1 = −41.26%, P = 0.007), FEV1%pred (RR-1 = −2.76%, P < 0.001), and influenza vaccination in the last year (RR-1 = −64.53%, P = 0.006) were all negatively correlated with COPD acute exacerbation (AE). COPD duration (RR-1 = 131.73%, P = 0.009), AE (RR-1 = 151.39%, P < 0.001), and COPD Assessment Test (CAT) scores (RR-1 = 3.82%, P = 0.019) were all positively correlated with COPD airflow limitation severity.

Conclusion

Differences exist in the diagnosis, treatment and management of COPD among different tiers of hospitals in China. Teaching hospitals can manage COPD patients relatively well. There are still some gaps compared with developed countries.

Assistive technologies for home NIV in patients with COPD: feasibility and positive experience with remote-monitoring and volume-assured auto-EPAP NIV mode

Background

Outcomes for patients with chronic obstructive pulmonary disease (COPD) with persistent hypercapnic respiratory failure are improved by long-term home non-invasive ventilation (NIV). Provision of home-NIV presents clinical and service challenges. The aim of this study was to evaluate outcomes of home-NIV in hypercapnic patients with COPD who had been set-up at our centre using remote-monitoring and iVAPS-autoEPAP NIV mode (Lumis device, ResMed).

Methods

Retrospective analysis of a data set of 46 patients with COPD who commenced remote-monitored home-NIV (AirView, ResMed) between February 2017 and January 2018. Events including time to readmission or death at 12 months were compared with a retrospectively identified cohort of 27 patients with hypercapnic COPD who had not been referred for consideration of home-NIV.

Results

The median time to readmission or death was significantly prolonged in patients who commenced home-NIV (median 160 days, 95% CI 69.38 to 250.63) versus the comparison cohort (66 days, 95% CI 21.9 to 110.1; p<0.01). Average time to hospital readmission was 221 days (95% CI, 47.77 to 394.23) and 70 days (95% CI, 55.31 to 84.69; p<0.05), respectively. Median decrease in bicarbonate level of 4.9 mmol/L (p<0.0151) and daytime partial pressure of carbon dioxide 2.2 kPa (p<0.032) in home-NIV patients with no required increase in nurse home visits is compatible with effectiveness of this service model. Median reduction of 14 occupied bed days per annum was observed per patient who continued home-NIV throughout the study period (N=32).

Conclusion

These findings demonstrate the feasibility and provide initial utility data for a technology-assisted service model for the provision of home-NIV therapy for patients with COPD.

Living conditions and autonomy levels in COPD patients receiving non-invasive ventilation: impact on health related quality of life

BACKGROUND

Research on health-related quality of life (HRQL) has become increasingly important in recent decades. However, the impact of both living conditions and the level of autonomy impairments on HRQL in COPD patients receiving non-invasive ventilation (NIV) is still unclear.

METHODS

The Severe Respiratory Insufficiency Questionnaire (SRI) was used to measure HRQL in a prospective cohort of COPD patients in whom home NIV was already established. Data on sociodemographics, clinical characteristics and standardized levels of autonomy impairment were evaluated. A multiple linear regression analysis was performed to identify the factors associated with a reduced HRQL.

RESULTS

A total of 137 patients (67.0 ± 7.8 years, 45% female) were assessed. The mean SRI Summary Score was 54.1 ± 16.9 (95%CI: 51.1-57.1; N = 127). Regular ambulatory care was provided in 76% of patients, but only 37% underwent pulmonary rehabilitation. Overall, 69% of patients lived with family members, while 31% lived alone (family situation). Autonomy impairment levels were most serious in 3%, serious in 14%, and significant in 29% of patients, while 54% had no impairments at all. Of note, higher levels of autonomy impairment were markedly associated with lower SRI scores (regression coefficient - 6.5 ± 1.1 per level; P < 0.001). In contrast, family situation (0.2 ± 3.0; P = 0.959), ambulatory care by a respiratory specialist (1.7 ± 3.6; P = 0.638), and pulmonary rehabilitation (- 0.8 ± 3.1; P = 0.802) did not appear to influence HRQL. Possible subgroup effects were evident for the factors "impaired autonomy" and "living in a nursing home" (P = 0.016).

CONCLUSION

A higher level of autonomy impairment has been identified as the major determinant of reduced HRQL in COPD-patients receiving long-term NIV, particularly in those living in a nursing home. Trial Registration German Clinical Trials Register (DRKS00008759).

Long-Term Domiciliary Noninvasive Ventilation for COPD

COPD can lead to abnormalities in oxygenation as well as ventilation. Thanks to pioneering work by Dr Thomas Petty, supplemental oxygen therapy has been shown to improve morbidity and mortality for individuals with COPD and severe daytime hypoxemia. However, efforts to augment ventilation have been less uniformly successful. Recent studies employing a so-called high-intensity noninvasive ventilation strategy, which used high inspiratory pressures and backup breathing frequency to reduce arterial carbon dioxide levels, have shown improved quality of life and reduced mortality. Thus, efforts are underway to better identify and treat patients with COPD who might benefit from noninvasive ventilation, though many practical questions remain.

Mortality and Healthcare Utilization of Patients with Compensated Hypercapnia

RATIONALE

Acute hypercapnic respiratory failure has been shown to be associated with worse outcomes for various disease states, but less is known about patients with compensated hypercapnic respiratory failure. Although these patients have a normal pH, it remains unknown whether chronically elevated partial pressures of carbon dioxide (PaCO2), irrespective of etiology, put patients at risk of adverse events.

OBJECTIVES

To understand the burden of and clinical factors associated with morbidity and mortality in patients with compensated hypercapnic respiratory failure.

METHODS

We performed a query of the electronic medical record (EMR) to identify patients hospitalized at the University of Michigan from January 1 - December 31, 2018 who had compensated hypercapnia, using a PaCO2 ≥ 50 mmHg and pH 7.35 - 7.45 on arterial blood gas (ABG). We obtained demographic and clinical data from the EMR. Survival probabilities for PaCO2 subgroups (50.0-54.9; 55.0-64.9; ≥65.0 mmHg) were determined using the Kaplan-Meier product limit estimator. Cox proportional hazard models were constructed to test the association between PaCO2 and all-cause mortality.

RESULTS

We identified 491 patients with compensated hypercapnia. The mean age was 60.5 ± 16.2. Patients were 57.4% male and 86.2% white. The mean pH and PaCO2 were 7.38 ± 0.03 and 58.8 ± 9.7 mmHg respectively. There were a total of 1,030 hospitalizations, with 44.4% of patients having 2 or more admissions. The median numbers of cumulative hospital and ICU days were 21.0 (IQR 11.0-38.0) and 7.0 (IQR 3.0-14.0) respectively. 217 patients (44.2%) died over a median of 592 days. In univariate analysis, every 5-mmHg increase in PaCO2 was associated with a higher risk of all-cause death (HR 1.09; 95% CI 1.03-1.16; p=0.004). This association was maintained after adjusting for age, sex, BMI, and the Charlson comorbidity index (HR 1.09 for every 5-mmHg increase in PaCO2; 95% CI 1.02-1.16; p=0.009). There was a statistically significant interaction between PaCO2 and BMI on mortality (p= 0.01 for the interaction term).

CONCLUSIONS

Patients with compensated hypercapnic respiratory failure have high mortality and healthcare utilization with higher PaCO2 associated with worse survival. Obese hypercapnic patients have higher risk of death with increases in PaCO2.

The impact of a telemedicine intervention on home non-invasive ventilation in a rural population with advanced COPD

INTRODUCTION

Rural regions have unique challenges with the implementation of new therapies upon discharge from the hospital due to multiple barriers.

OBJECTIVES

We investigated the effect of home non-invasive ventilation (NIV) plus the implementation of a call center following hospitalization for acute exacerbations of COPD (chronic obstructive lung disease) on NIV usage and readmissions.

METHODS

In this prospective pilot study, consecutive patients were screened at our institution for diagnosis of hypercarbic respiratory failure or COPD exacerbation from 2018 to 2019. Patients with more than two admissions in the last year were reviewed for eligibility. Of the 82 patients screened, 22 were eligible. There were 10 participants randomized to the intervention (NIV and call center) arm and 10 to NIV alone.

RESULTS

A total of 20 patients were randomized (mean age of 64, 45% males, BMI of 32). At three months, average usage was 32.1 days out of 90, 35%. When comparing the call center group to the standard group, there was a statistically significant difference in total days of device usage 48.7 compared to 15.5 (significant U-value of 16, critical value of U at p<.05 of 27) and cumulative use in hours 284 versus 87.7 (significant U-value of 20). Participants in the call center group were readmitted on average 4.2 times compared to 2.4 in the control group which was not statistically different (non-significant U-value of 42). In the follow-up period, 9/20 (45%) of the participants died.

CONCLUSION

This pilot study highlights the challenges in implementing care for advanced COPD in a rural population. Our data suggest that telemedicine may favorably address therapy adherence.

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.

Non-invasive ventilation intervention during exercise training in individuals with chronic obstructive pulmonary disease: A systematic review and meta-analysis

OBJECTIVE

evidence is inconsistent for the effect of non-invasive ventilation (NIV) for individuals with chronic obstructive pulmonary disease (COPD) during exercise training. This review aimed to determine the effect of NIV in COPD individuals during exercise training on exercise capacity, quality of life, functional performance and symptoms.

MATERIAL AND METHODS

we searched for studies evaluating the effect of NIV on COPD individuals during exercise training published until May 2020 in 6 electronic databases (PubMed, Embase, Cochrane Library, Web of Science, clinical trial registers and Wanfang). The included studies were appraised with the Cochrane Risk of Bias tool and Downs and Black criteria. The primary outcomes were improvement in 6-min walking distance and quality of life. Mean difference (MD) or standardized mean difference (SMD) with 95% confidence intervals (CIs) was calculated.

RESULTS

among 855 identified articles, reports for 15 studies with heterogeneous populations were eligible, with 520 individuals: 257 in the NIV group and 263 in the control group. Across studies, NIV intervention during exercise training affected exercise performance (6-min walking distance: SMD: 0.33, 95% CI: 0.06; 0.59, P=0.02; quality of life: SMD: -0.77, 95% CI: -1.01; -0.53, P<0.001). In the analysis of dyspnea, pooled estimates demonstrated improvement in the NIV versus control group. NIV intervention was also better than exercise alone in ameliorating oxygen saturation, PaO2, PaCO2, blood lactate level and breath rate. The groups did not differ in duration of exercise, BODE index, minute ventilation, heart rate and systolic blood pressure.

CONCLUSIONS

our review suggests that NIV is a relevant adjuvant for exercise training in COPD individuals because the intervention could improve exercise performance and quality of life. The current results also demonstrate the importance of further investigations of higher methodological quality to assess the effect on exercise capacity and quality of life.

Noninvasive Ventilator Devices and Modes

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

Effects of volume-assured pressure support noninvasive ventilation in stable COPD with chronic respiratory failure: Meta-analysis and literature review

BACKGROUND

Patients receiving long-term home noninvasive ventilation (NIV) may slow down the progression to acute exacerbation of chronic obstructive pulmonary disease (AECOPD), however, the problem with respiratory instability during sleep diminished was persisted, which may reduce the effectiveness of NIV and the patient's quality of life. A novel NIV mode with volume-assured pressure support (VAPS) has been gradually applied to improve sleep quality in COPD patients with chronic respiratory failure. This meta-analysis aimed to evaluate the efficacy of VAPS in stable COPD patients with chronic respiratory failure.

METHODS

We performed an electronic literature search for RCTs from January 2008 to October 2018. Studies investigating the effects of VAPS in stable COPD patients with chronic respiratory failure were conducted, and the following primary outcomes were reviewed: effectiveness of ventilation, sleep quality, and quality of life.

RESULTS

Five studies with 150 subjects were identified. While questionnaire scores showed significant improvements in the VAPS mode, no significant difference was found in the effectiveness of ventilation (pH, MD = 0.01 [95% CI -0.01 to 0.02, P = 0.27]; PaCO₂, MD = 1.25 [95% CI -1.45 to 3.95, P = 0.37]; PaO₂, MD = 3.14 [95% CI -0.76 to 7.05, P = 0.11]; mSaO₂, MD = 0.23 [95% CI -1.22 to 1.67, P = 0.76]; mPtcCO₂, MD = 3.03 [95% CI -6.06 to- 0.60, P = 0.10]). The VAPS mode did not seem to ameliorate sleep quality and quality of life.

CONCLUSION

The VAPS mode had similar efficacy as the pressure-support (PS) mode. However, VAPS could significantly improve the patients' subjective feelings.

Clinical Evidence of Nasal High-Flow Therapy in Chronic Obstructive Pulmonary Disease Patients

Nasal high-flow therapy (NHFT) is an upcoming treatment for chronic obstructive pulmonary disease (COPD) patients. It supplies heated, humidified, and, desirably, oxygen-enriched air through a nasal cannula at flow rates up to 60 L/min. Several studies examined the effect of NHFT in COPD patients, but a clear overview is lacking. The present review aimed to give an overview of the clinical evidence of NHFT in 3 aspects of COPD care: long-term use in stable COPD patients, use for treatment of COPD exacerbations, and use during exercise therapy in COPD. For each topic, a specific literature search was performed up to December 9, 2019. Studies show promising results, with most evidence for its long-term use in hypoxemic COPD patients that frequently exacerbate, and very limited evidence for its use during COPD exacerbations or as a worthwhile adjunct to exercise training. More evidence is therefore needed to know how to incorporate NHFT in standard clinical practice.

A Low-Cost Breath Analyzer Module in Domiciliary Non-Invasive Mechanical Ventilation for Remote COPD Patient Monitoring

Smart Breath Analyzers were developed as sensing terminals of a telemedicine architecture devoted to remote monitoring of patients suffering from Chronic Obstructive Pulmonary Disease (COPD) and home-assisted by non-invasive mechanical ventilation via respiratory face mask. The devices based on different sensors (CO₂/O₂ and Volatile Organic Compounds (VOCs), relative humidity and temperature (R.H. & T) sensors) monitor the breath air exhaled into the expiratory line of the bi-tube patient breathing circuit during a noninvasive ventilo-therapy session; the sensor raw signals are transmitted pseudonymized to National Health Service units by TCP/IP communication through a cloud remote platform. The work is a proof-of-concept of a sensors-based IoT system with the perspective to check continuously the effectiveness of therapy and/or any state of exacerbation of the disease requiring healthcare. Lab tests in controlled experimental conditions by a gas-mixing bench towards CO₂/O₂ concentrations and exhaled breath collected in a sampling bag were carried out to test the realized prototypes. The Smart Breath Analyzers were also tested in real conditions both on a healthy volunteer subject and a COPD suffering patient.

Psychosocial Interventions for Patients with Severe COPD-An Up-to-Date Literature Review

Background and Objectives: Chronic obstructive pulmonary disease (COPD) is a life limiting condition with a long list of serious psychosocial consequences, aggravating with illness progression. In advanced stages, chronic respiratory failure often develops, which might undermine mental health and reduce activity. The study objective was to review the recent studies concerning psychosocial interventions dedicated to patients with severe COPD. Materials and Methods: The PubMed database was searched for terms, such as ‘COPD and long-term oxygen therapy, non-invasive ventilation, severe or respiratory failure’ and ‘psychological or psychosocial or mental health and intervention.’ Studies were included that described patients with stable, severe COPD and the outcomes of psychosocial interventions. Results and Conclusions: Thirty-four studies were identified and divided into four thematic groups: home medical support, exercise, self-management and mental health. The number of studies that focused on mental health preservation in severe COPD was very limited; i.e., none refer directly to those treated with respiratory failure. Improving patients’ self-efficacy gave promising effects to the acceptance of palliative care, pulmonary rehabilitation completion and mental health. Physical activity might be recommended to be included in interventions for mental health enhancement, although little is known about the role of the particular forms of exercise. An increasing beneficial use of new technologies for psychosocial interventions was noted. Psychosocial interventions applied in advanced COPD underline the roles of self-efficacy, telehealth and physical activity in physical and mental health preservation. However, all of the above elements need to be independently tested on more homogenous groups of patients and have the possible modes of their treatment analysed.

Diagnosis and management of chronic obstructive pulmonary disease in Serbia: an expert group position statement

In recent years, several national chronic obstructive pulmonary disease (COPD) guidelines have been issued. In Serbia, the burden of COPD is high and most of the patients are diagnosed at late stages. Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy is poorly implemented in real-life practice, as many patients are still prescribed inhaled corticosteroids (ICS)-containing regimens and slow-release theophylline. In this document, we propose an algorithm for treating COPD patients in Serbia based on national experts’ opinion, taking into account global recommendations and recent findings from clinical trials that are tailored according to local needs. We identified four major components of COPD treatment based on country specifics: active case finding and early diagnosis in high-risk population, therapeutic algorithm for initiation and escalation of therapy that is simple and easy to use in real-life practice, de-escalation of ICS in low-risk non-exacerbators, and individual choice of inhaler device based on patients' ability and preferences. With this approach we aim to facilitate implementation of the recommendation, initiate the treatment in early stages, improve cost-effectiveness, reduce possible side effects, and ensure efficient treatment.

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.