AVAPS-AE versus ST mode: A randomized controlled trial in patients with obesity hypoventilation syndrome

Ventilation in the obese: physiological insights and management

Obesity can have profound adverse effects on the respiratory system, including an impact on pulmonary function, respiratory mechanics, respiratory muscle strength and endurance, gas exchange, control of breathing, and exercise capacity. Lung mechanics are modified by increased pleural pressure resulting from increased abdominal mass and subsequent peripheral airway occlusion and worsening of lung compliance due to reduced functional residual capacity without impairment of chest wall compliance. Arterial blood gases are frequently altered in these subjects and these abnormalities are directly proportional to body mass index. Mechanisms that may account for gas exchange abnormalities are multiple: ventilation/perfusion inequality (responsible for isolated hypoxaemia) and alveolar hypoventilation (responsible for so-called "obesity hypoventilation syndrome" (OHS)). Hypoventilation in obese patients results from a diversity of mechanisms, among which the two most frequently raised are mechanical limitation and blunted ventilatory drive. OHS is frequently underappreciated and diagnosis is frequently made during a first acute exacerbation. Obstructive sleep apnoea is a condition frequently associated with obesity and must be systematically screened for in this population because of its impact on morbidity and therapeutic management. Ventilatory management of these patients will depend on the patient's underlying situation, clinical presentation and physiology, including sleep study results; it may include continuous positive airway pressure or non-invasive ventilation. The goal of this narrative review is to provide a physiological-based overview of the impact of obesity on the respiratory system with a special focus on ventilatory management of patients with obesity-related respiratory disturbances.

The role of the AVAPS ventilation mode combined with TCM monitoring in weaning patients with AECOPD

To explore the role of AVAPS combined with TCM monitoring in the weaning of patients with AECOPD. In this study, 100 patients with AECOPD were included, who were divided into the AVAPS group and the S/T group after weaning. The respiration-related parameters were compared between the two groups at the time of weaning and after 1 h and 12 h of noninvasive ventilation. The correlations between PtcCO2 and PaCO2 and the differences in each parameter were compared. The predictive value of PtcCO2 variability after 1 h and 12 h of noninvasive respiratory support for the 48-h reintubation rate were analysed. Logistic regression analysis was performed to explore the risk factors affecting the 48-h reintubation rate of AECOPD patients. After 1 h and 12 h of treatment with different ventilation modes, the variations in the respiration-related parameters in the AVAPS group were all significantly greater than those in the S/T group (P < 0.05). In the AVAPS group, the incidence of 48-hour reintubation was lower, the time to reintubation was longer, and length of hospital and ICU stays were shorter (P < 0.05). The ROC curve revealed that PtcCO2 variability- 2, the ROX index- 2 and their combination had predictive value for the 48-h reintubation rate of AECOPD patients. The logistic regression revealed that after 12 h of noninvasive support, a PtcCO2 variability ≥ - 5.8% with a ROX index ≤ 9.6 was independent risk factors affecting the 48 h reintubation rate in weaning patients with AECOPD (OR = 2.815; P < 0.05). For patients with AECOPD, the AVAPS ventilation mode combined with PtcCO2 monitoring can significantly improve respiratory physiological parameters and reduce the 48 h reintubation rate. After 12 h of noninvasive support, a PtcCO2 variability ≥ - 5.8% with a ROX index ≤ 9.6 is considered as a independent risk factor for reintubation 48 h after weaning.

Clinical review of non-invasive ventilation

Non-invasive ventilation (NIV) is the mainstay to treat patients who need augmentation of ventilation for acute and chronic forms of respiratory failure. The last several decades have witnessed an extension of the indications for NIV to a variety of acute and chronic lung diseases. Evolving advancements in technology and personalised approaches to patient care make it feasible to prioritise patient-centred care models that deliver home-based management using telemonitoring and telemedicine systems support. These trends may improve patient outcomes, reduce healthcare costs and improve the quality of life for patients who suffer from chronic diseases that precipitate respiratory failure.

Australasian Sleep Association 2024 guidelines for sleep studies in adults

Executive summary: This document is a consensus statement of a subcommittee of experienced sleep physicians and scientists, tasked to review the literature and formulate recommendations on the indications, performance, and reporting of sleep studies, to update clinical practice from the 2017 Australasian Sleep Association (ASA) guidelines for sleep studies in adults (Douglas JA, Chai-Coetzer CL, McEvoy D, et al. Guidelines for sleep studies in adults - a position statement of the Australasian Sleep Association. Sleep Med. 2017;36(Suppl 1):S2-S22. doi:10.1016/j.sleep.2017.03.019). This document moves the focus beyond important discussions outlined in the 2017 guidelines, particularly surrounding the sensitivity and specificity of validated questionnaires and home sleep studies. The 2024 guide outlines the performance of the broad range of sleep testing available for the investigations of sleep disorders in adults including indications, strengths, limitations, and reporting standards.

Initiation of Chronic Non-invasive Ventilation

Initiation of home non-invasive ventilation (NIV) requires careful consideration of the patient's condition, motivation, expectations, wishes, and social circumstances. The decision to start NIV depends on a combination of factors including patient symptoms and objective evidence of nocturnal hypoventilation. A solid understanding of the underlying pathophysiology is key to a systematic and well-balanced clinical approach to titrating NIV. The location where NIV is initiated is not the most relevant issue, provided that it is a comfortable, safe environment in which adequate monitoring can be assured. The majority of patients prefer their own home for treatment initiation.

[Take-home messages from the 2nd COPD 2023 Biennial of the French Society of Respiratory Diseases. Placing the patient at the center of the care pathway]

INTRODUCTION

The second COPD Biennial organized by the COPD working group of the French Society of Respiratory Diseases took place in Paris (Cochin) on 13th December 2023.

STATE OF THE ART

Major trends in 2023 were discussed; they encompassed concepts, definitions, biologics, care pathways, pulmonary rehabilitation and complex situations entailed by respiratory infections, cardiovascular comorbidities and pulmonary hypertension, and modalities of oxygen therapy and ventilation.

PERSPECTIVES

The different talks underlined major changes in COPD including the concepts of pre-COPD, etiotypes, health trajectories and new definitions of exacerbation. Recent results in biologics for COPD open the door to new pharmacological options. Assessment of current care pathways in France highlighted some causes for concern. For example, pulmonary rehabilitation is a key but insufficiently practiced element. Respiratory infections require careful assessment and treatments. Diagnosis and treatment of cardiovascular comorbidities and pulmonary hypertension are of paramount importance. As of late, oxygen therapy and ventilation modalities have evolved, and are beginning to afford more personalized options.

CONCLUSIONS

As regards COPD, a personalized approach is crucial, placing the patient at the center of the care pathway and facilitating coordination between healthcare providers.

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

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

An exposed/unexposed cohort study assessing the effectiveness, the safety and the survival of patients established on home non-invasive ventilation after 80 years old

BACKGROUND

Little is known about the use of long-term non-invasive ventilation (NIV) in the elderly. We aimed to assess if the effectiveness of long-term NIV of patients ≥ 80 years (older) was not greatly inferior to that of patients < 75 years (younger).

METHODS

This retrospective exposed/unexposed cohort study included all patients established on long-term NIV treated at Rouen University Hospital between 2017 and 2019. Follow-up data were collected at the first visit following NIV initiation. The primary outcome was daytime PaCO2 with a non-inferiority margin of 50% of the improvement of PaCO2 for older patients compared to younger patients.

RESULTS

We included 55 older patients and 88 younger patients. After adjustment on the baseline PaCO2, the mean daytime PaCO2 was reduced by 0.95 (95% CI: 0.67; 1.23) kPa in older patients compared to1.03 (95% CI: 0.81; 1.24) kPa in younger patients for a ratio of improvements estimated at 0.95/1.03 = 0.93 (95% CI: 0.59; 1.27, one-sided p = 0.007 for non-inferiority to 0.50). Median (interquartile range) daily use was 6 (4; 8.1) hours in older versus 7.3 (5; 8.4) hours in younger patients. No significant differences were seen in the quality of sleep and NIV safety. The 24-months survival was 63.6% in older and 87.2% in younger patients.

CONCLUSIONS

effectiveness and safety seemed acceptable in older patients, with a life expectancy long enough to expect a mid-term benefit, suggesting that initiation of long-term NIV should not be refused only based on age. Prospective studies are needed.

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.

Quality of life in patients with chronic respiratory failure on home mechanical ventilation

Home mechanical ventilation (HMV) is a treatment for chronic respiratory failure that has shown clinical and cost effectiveness in patients with underlying COPD, obesity-related respiratory failure and neuromuscular disease (NMD). By treating chronic respiratory failure with adequate adherence to HMV, improvement in patient-reported outcomes including health-related quality of life (HRQoL) have been evaluated using general and disease-specific quantitative, semi-qualitative and qualitative methods. However, the treatment response in terms of trajectory of change in HRQoL is not uniform across the restrictive and obstructive disease groups. In this review, the effect of HMV on HRQoL across the domains of symptom perception, physical wellbeing, mental wellbeing, anxiety, depression, self-efficacy and sleep quality in stable and post-acute COPD, rapidly progressive NMD (such as amyotrophic lateral sclerosis), inherited NMD (including Duchenne muscular dystrophy) and obesity-related respiratory failure will be discussed.

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

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

Ventilators, Settings, Autotitration Algorithms

The choice of a ventilator model for a single patient is usually based on parameters such as size (portability), presence or absence of battery and ventilatory modes. However, there are many details within each ventilator model about triggering, pressurisation or autotitration algorithms that may go unnoticed, but may be important or may justify some drawbacks that may occur during their use in individual patients. This review is intended to emphasize these differences. Guidance is also provided on the operation of autotitration algorithms, in which the ventilator is able to take decisions based on a measured or estimated parameter. It is important to know how they work and their potential sources of error. Current evidence on their use is also provided.

Cost-effectiveness of outpatient versus inpatient non-invasive ventilation setup in obesity hypoventilation syndrome: the OPIP trial

BACKGROUND

Current guidelines recommend that patients with obesity hypoventilation syndrome (OHS) are electively admitted for inpatient initiation of home non-invasive ventilation (NIV). We hypothesised that outpatient NIV setup would be more cost-effective.

METHODS

Patients with stable OHS referred to six participating European centres for home NIV setup were recruited to an open-labelled clinical trial. Patients were randomised via web-based system using stratification to inpatient setup, with standard fixed level NIV and titrated during an attended overnight respiratory study or outpatient setup using an autotitrating NIV device and a set protocol, including home oximetry. The primary outcome was cost-effectiveness at 3 months with daytime carbon dioxide (PaCO₂) as a non-inferiority safety outcome; non-inferiority margin 0.5 kPa. Data were analysed on an intention-to-treat basis. Health-related quality of life (HRQL) was measured using EQ-5D-5L (5 level EQ-5D tool) and costs were converted using purchasing power parities to £(GBP).

RESULTS

Between May 2015 and March 2018, 82 patients were randomised. Age 59±14 years, body mass index 47±10 kg/m² and PaCO₂ 6.8±0.6 kPa. Safety analysis demonstrated no difference in ∆PaCO₂ (difference -0.27 kPa, 95% CI -0.70 to 0.17 kPa). Efficacy analysis showed similar total per-patient costs (inpatient £2962±£580, outpatient £3169±£525; difference £188.20, 95% CI -£61.61 to £438.01) and similar improvement in HRQL (EQ-5D-5L difference -0.006, 95% CI -0.05 to 0.04). There were no differences in secondary outcomes.

DISCUSSION

There was no difference in medium-term cost-effectiveness, with similar clinical effectiveness, between outpatient and inpatient NIV setup. The home NIV setup strategy can be led by local resource demand and patient and clinician preference.

TRIAL REGISTRATION NUMBERS

NCT02342899 and ISRCTN51420481.

Noninvasive Mechanical Ventilation with Average Volume-Assured Pressure Support versus BiPAP S/T in De Novo Hypoxemic Respiratory Failure

Background

Bilevel positive airway pressure in spontaneous/time and average volume-assured pressure support (BiPAP·S/T-AVAPS) could maintain an adequate tidal volume by reducing the patient's inspiratory effort; however, this ventilatory strategy has not been compared with other ventilatory modes, especially the conventional BiPAP S/T mode, when noninvasive mechanical ventilation (NIMV) is used. The primary objective of this study was to determine the rate of success and failure of the use of BiPAP·S/T-AVAPS versus BiPAP·S/T alone in patients with mild-to-moderate "de novo" hypoxemic respiratory failure.

Methods

This was a matched-cohort study. Subjects with mild-to-moderate de novo hypoxemic respiratory failure were divided into two groups according to the ventilatory strategy used. The subjects in the BiPAP·S/T group were paired with those in the BiPAP·S/T-AVAPS group.

Results

A total of 58 subjects were studied. Twenty-nine subjects in the BiPAP·S/T group were paired with 29 subjects in the BiPAP·S/T-AVAPS group. Twenty patients (34.5%) presented with "failure of NIMV," while 38 (65.5%) patients did not. In addition, 13 (22.4%) patients died, while 45 (77.6%) recovered. No differences were found in the percentage of intubation (P=0.44) and mortality (P=0.1).

Conclusion

The BiPAP S/T-AVAPS ventilator mode was not superior to the BiPAP·S/T mode. A high mortality rate was observed in patients with NIMV failure in both modes. This trial is registered with https://doi.org/10.1186/ISRCTN17904857.

PAP therapy and readmission rates after in-hospital laboratory titration polysomnography in patients with hypoventilation

STUDY OBJECTIVES

Hypoventilation associated with sleep disordered breathing in inpatients is associated with higher risk of morbidity, hospitalizations and death. In-hospital titration polysomnography qualifies patients for positive airway pressure (PAP) therapy and optimizes settings, but impact is unknown. This study describes a process for in-hospital sleep testing and evaluates subsequent PAP adherence and readmission.

METHODS

A retrospective cohort of patients with hypoventilation and in-hospital titration polysomnography with available PAP data were analyzed to determine whether PAP adherence was associated with 90-day readmission. Absolute differences were obtained using logistic regression models. Models were adjusted for body mass index, age and Elixhauser Index. PAP adherence and nonadherence were defined as ≥ 4 and < 4 hours daily average use prior to readmission or first 90-days post-discharge.

RESULTS

81 patients, 50.6% male, age (mean ± SD) 61.1 ± 13.5 years were included. Comorbid sleep disorders included 91.4% with OSA and 23.5% with central sleep apnea. 28/52 (53.8%) nonadherent and 6/29 (20.7%) adherent patients had 90-day readmissions. 11 (13.6%) patients (all nonadherent) were readmitted within 2 weeks of discharge. Adjusted model showed a 35.6% (95% CI 15.9%-55.2%) reduction in 90-day readmission in adherent group compared to nonadherent (p=0.004). Similar reductions in readmission were found with adherence ≥ 50% and ≥ 70% days ≥ 4 hours. Male sex, treatment with iVAPS, and highest CO₂ ≥ 60 mmHg on polysomnography were associated with largest differences in readmission rates between adherent and nonadherent patients.

CONCLUSIONS

Adherence to optimized PAP therapy after in-hospital titration polysomnography in patients with hypoventilation may decrease readmissions.

Pediatric Average Volume Assured Pressure Support

Average volume assured pressure support (AVAPS) is a modality of non-invasive ventilation that enables the machine to deliver a pre-set tidal volume by adjusting the inspiratory pressure support within a set range. Data on its use in the pediatric population are limited to case reports and single centre case series. This article reviews paediatric data on use of AVAPS and highlights the need for validation to help develop specific guidelines on use of AVAPS in children.

Optimal Noninvasive Medicare Access Promotion: Patients with Hypoventilation Syndromes A Technical Expert Panel Report from the American College of Chest Physicians, the American Association for Respiratory Care, the American Academy of Sleep Medicine, and the American Thoracic Society

The existing coverage criteria for home noninvasive ventilation (NIV) do not recognize the diversity of hypoventilation syndromes and advances in technologies. This document summarizes the work of the Hypoventilation Syndromes Technical Expert Panel working group. The most pressing current coverage barriers identified were: 1) overreliance on arterial blood gases (particularly during sleep); 2) need to perform testing on prescribed oxygen; 3) requiring a sleep study to rule out obstructive sleep apnea as the cause of sustained hypoxemia; 4) need for spirometry; 5) need to demonstrate BPAP without a backup rate failure to qualify for BPAP S/T; and 6) qualifying hospitalized patients for home NIV therapy at the time of discharge. Critical evidence support for changes to current policies include randomized clinical trial evidence and clinical practice guidelines. In order to decrease morbidity-mortality by achieving timely access to NIV for patients with hypoventilation, particularly those with obesity hypoventilation syndrome, we make the following key suggestions: 1) Given the significant technological advances, we advise acceptance of surrogate noninvasive end tidal and transcutaneous PCO₂ and venous blood gases in lieu of arterial blood gases,; 2) Not requiring PCO₂ measures while on prescribed oxygen; 3) Not requiring a sleep study to avoid delays in care in patients being discharged from the hospital; 4) Remove spirometry as a requirement; 5) Not requiring BPAP without a backup rate failure to approve BPAP S/T. The overarching goal of the Technical Expert Panel is to establish pathways that improve clinicians' management capability to provide Medicare beneficiaries access to appropriate home NIV therapy. Adoption of these proposed suggestions would result in the right device, at the right time, for the right type of patients with hypoventilation syndromes.

Defining successful non-invasive ventilation initiation: Data from a real-life cohort

BACKGROUND AND OBJECTIVE

When home non-invasive ventilation (NIV) is initiated, five goals need to be achieved: a daily use >4 h/day, an improvement in gas exchange, health-related quality of life (HRQL) and sleep quality without side effects. Our aim was to assess how frequently these five goals were reached and the factors predictive of achievement.

METHODS

We conducted a monocentric cohort study that included patients electively established on home NIV over 2 years. HRQL was assessed at baseline and follow-up by the Severe Respiratory Insufficiency questionnaire. Adequate initiation was defined as the achievement of at least three of five goals and successful initiation as the achievement of all.

RESULTS

Two-hundred and fifty patients were included at baseline. NIV was initiated for: obesity hypoventilation syndrome (n = 95; 38%), neuromuscular disease (n = 70; 28%), chronic obstructive pulmonary disease (n = 66; 26%) and chest wall disease (n = 19; 8%). At follow-up, measures of all five goals were available in 141 (56%) patients. NIV initiation was adequate for 96 (68%) patients and successful for 12 (9%) patients. In multivariate analysis, a tidal volume ≥ 7.8 ml/kg of ideal body weight was associated with an increased likelihood of adequate NIV initiation (hazard ratio: 5.765 [95% CI:1.824-18.223], p = 0.006]. Improvement in daytime partial arterial carbon dioxide pressure (PaCO₂ ) was not correlated to improvement in HRQL or sleep quality. Severe to very severe NIV-related side effects occurred in 114 (47%) patients and were associated with higher daytime PaCO₂ (6.35 ± 1.08 vs. 5.92 ± 0.79 kPa, p < 0.001).

CONCLUSION

Successful home NIV initiation is rarely achieved in real life. HRQL and NIV tolerance should be assessed to improve patient-centred outcomes.

Contemporary Concise Review 2020: Sleep

Obstructive sleep apnoea (OSA) now affects one-seventh of the world's population. Treatment of even mild OSA can improve daytime sleepiness and quality of life. Recent modifications to uvulopalatopharyngoplasty may make it a more widely applicable treatment option in selected patients with OSA. Diet and exercise have effects on sleep apnoea severity independent of weight loss. Insomnia has become increasingly common during the coronavirus disease 2019 (COVID-19) pandemic.

Use of average volume-assured pressure support as a therapeutic option in patients with central sleep apnea syndrome

PURPOSE

Central sleep apnea (CSA) syndrome commonly occurs with other medical conditions such as congestive heart failure, opiate use, and brainstem disorders. Various treatment modalities have been used with varied effectiveness in an attempt to improve ventilation and reduce the apnea-hypopnea index (AHI) in patients with CSA. This study evaluated whether or not a bilevel positive airway pressure mode of noninvasive ventilation, average volume-assured pressure support (AVAPS) is effective in treating CSA.

METHODS

This was a retrospective review of patients with CSA who underwent AVAPS titration studies at our institution. We included patients with CSA with apnea-hypopnea index (events/hour) (AHI) ≥ 15, and examined the effectiveness of AVAPS in reducing AHI, improving oxygenation parameters, and improving sleep architecture.

RESULTS

There were 12 patients, with mean age 62.8 ± 11.5 years, body mass index (BMI) 33.5 ± 4.7 kg/m², 8 men, and Epworth Sleepiness Scale 9.3 ± 4.9. Five patients had CSA attributed to opiate use, 4 patients had CSA with Cheyne-Stokes respiration, and 3 patients had primary CSA. The only significant change from baseline PSG was AHI reduction with AVAPS: 63.3 ± 19.1 to 30.5 ± 30.3 (p < 0.003). In 5 patients (42%), AHI was reduced to < 15 with AVAPS use. Improvement in AHI was not related to gender, BMI, opiate use, or age. Defining response to therapy as AHI reduced to < 15, we found that lack of hypertension was the only significant predictor of response (p = 0.045). No significant changes in sleep architecture between the two studies were found.

CONCLUSION

AVAPS is an effective mode of treating CSA in a significant proportion of patients. More studies are needed to confirm these findings and determine what factors are associated with response to therapy.

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

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

Novel modes of non-invasive ventilation in chronic respiratory failure: a narrative review

Home non-invasive ventilation (NIV) is central in the management of chronic hypercapnic respiratory failure and is associated with improvements in clinically relevant outcomes. Home NIV typically involves delivery of fixed positive inspiratory and expiratory airway pressures. These pressures do not reflect physiological changes to respiratory mechanics and airway calibre during sleep, which may impact on physiological efficacy, subsequent clinical outcomes, and therapy adherence. Novel ventilator modes have been designed in an attempt to address these issues. Volume-assured pressure support modes aim to automatically adjust inspiratory pressure to achieve a pre-set target tidal volume. The addition of auto-titrating expiratory pressure to maintain upper airway calibre is designed for patients at risk of upper airway collapse, such as obese patients and those with obstructive sleep apnoea complicating their hypercapnic failure. Heterogeneity in setup protocols, patient selection and trial design limit firm conclusions to be drawn on the clinical efficacy of these modes. However, there are data to suggest that compared to fixed-pressure NIV, volume-assured modes may improve nocturnal carbon dioxide, sleep quality and ventilator adherence in select patients. The use of the forced oscillation technique to identify expiratory flow limitation and adjust expiratory pressure to eliminate it is the most recent addition to these advanced modes and is yet to be assessed in formal clinical trials.

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.