Randomized trial of 'intelligent' autotitrating ventilation versus standard pressure support non-invasive ventilation: impact on adherence and physiological outcomes

New noninvasive modalities in long-term pediatric ventilation: a scoping review

Long-term noninvasive ventilation modalities for the pediatric population have undergone a continuous evolution. Hybrid noninvasive ventilation modalities have been recently introduced in clinical practice. Combining the advantages of conventional ventilation, hybrid modes use algorithms that automatically adjust the ventilator's settings to achieve a predefined ventilation target. Most of the recommendations on the use and settings of hybrid noninvasive ventilation modalities in children are derived from adult experience. Therefore, there is a lack of evidence on its implementation in pediatric chronic respiratory diseases. This scoping review aims to map the existing information regarding the use of hybrid ventilation modalities in the pediatric population and identify knowledge or research gaps. We performed a literature search using MEDLINE and Pubmed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. We included 13 studies (ten studies on average volume-assured pressure-support ventilation; two studies on intelligent volume-assured pressure-support ventilation; and one study on adaptive servoventilation). The use of new noninvasive ventilation modes in the pediatric population has been applied for the treatment of neuromuscular and hypoventilation syndromes as an alternative therapeutic option in the case of the failure of conventional noninvasive ventilation. Their widespread use has been hampered by the limited evidence available. Longitudinal studies on a larger number of patients are needed to confirm their effectiveness and evaluate their long-term clinical and functional outcomes.

Volume assured pressure support mode use for non-invasive ventilation in pediatrics

There has been increasing interest in utilizing volume assured pressure support (VAPS) modes of ventilation for children, which historically had only been favored in adult populations. In addition to patients with obesity hypoventilation syndrome, newer pediatric populations for which it has recently been prescribed include congenital central hypoventilation syndrome and children with neuromuscular disease such as Duchenne muscular dystrophy and spinal muscular atrophy. Given its expanding use in pediatrics, greater familiarity with VAPS is essential for pediatric pulmonologists and sleep physicians. This review article will highlight methods of initiation for this mode, specific ventilator settings, discussion of suitable pediatric patient populations, ventilator titrations via formal polysomnograms and detailed ventilator data downloads specific interpretation. Finally, common challenges to be aware of and how to troubleshoot relevant machine alarms will be reviewed.

Are all ventilators for NIV performing the same? A bench analysis

Global pandemic due to COVID-19 has increased the interest for ventilators´ use worldwide. New devices have been developed and older ones have undergone a renewed interest, but we lack robust evidence about performance of each ventilator to match appropriate device to a given patient and care environment. The aim of this bench study was to investigate the performance of six devices for noninvasive ventilation, and to compare them in terms of volume delivered, trigger response, pressurization capacity and synchronization in volume assisted controlled and pressure support ventilation. All ventilators were tested under thirty-six experimental conditions by using the lung model ASL5000® (IngMar Medical, Pittsburgh, PA). Two leak levels, two muscle inspiratory efforts and three mechanical patterns were combined for simulation. Trigger function was assessed by measurement of trigger-delay time. Pressurization capacity was evaluated as area under the pressure-time curve over the first 500 ms after inspiratory effort onset. Synchronization was evaluated by the asynchrony index and by incidence and type of asynchronies in each condition. All ventilators showed a good performance, even if pressurization capacity was worse than expected. Leak level did not affect their function. Differences were found during low muscle effort and obstructive pattern. In general, Philips Trilogy Evo/EV300 and Hamilton C3 showed the best results. NIV devices successfully compensate air leaks but still underperform with low muscle effort and obstructive lungs. Clinicians´ must have a clear understanding of the goals of NIV both for devices´ choice and set main parameters to achieve therapy success.

Effectiveness of long-term noninvasive ventilation measured by remote monitoring in neuromuscular disease

Background and objective

Patients with neuromuscular disease are often treated with home noninvasive ventilation (NIV) with devices capable of remote patient monitoring. We sought to determine whether long-term NIV data could provide insight into the effectiveness of ventilation over time.

Methods

We abstracted available longitudinal data for adults with neuromuscular disease in monthly increments from first available to most recent. Generalised linear mixed-effects modelling with subject-level random effects was used to evaluate trajectories over time.

Results

1799 months of data across 85 individuals (median age 61, interquartile range (IQR) 46-71 years; 44% female; 49% amyotrophic lateral sclerosis (ALS)) were analysed, with a median (IQR) of 17 (8-35) months per individual. Over time, tidal volume increased and respiratory rate decreased. Dynamic respiratory system compliance decreased, accompanied by increased pressure support. Compared to volume-assured mode, fixed-pressure modes were associated with lower initial tidal volume, higher respiratory rate and lower pressures, which did not fully equalise with volume-assured mode over time. Compared with non-ALS patients, those with ALS had lower initial pressure support, but faster increases in pressure support over time, and ALS was associated wtih a more robust increase in respiratory rate in response to low tidal volume. Nonsurvivors did not differ from survivors in ventilatory trajectories over time, but did exhibit decreasing NIV use prior to death, in contrast with stable use in survivors.

Conclusion

NIV keeps breathing patterns stable over time, but support needs are dynamic and influenced by diagnosis and ventilation mode. Mortality is preceded by decreased NIV use rather than inadequate support during use.

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.

Role of Average Volume Assured Pressure Support Mode (AVAPS) in the Management of Acute Exacerbation of Chronic Obstructive Pulmonary Disease With Type 2 Respiratory Failure

Background Non-invasive ventilation (NIV) is a well-established approach in the treatment of acute exacerbation of chronic obstructive pulmonary disease (COPD) with type 2 respiratory failure. Average volume-assured pressure support (AVAPS) mode integrates the characteristics of both volume and pressure-controlled modes of NIV. In bilevel positive airway pressure (BiPAP) mode, volume is the dependent variable, whereas in AVAPS mode, pressure is the dependent variable. In this study, we aimed to compare the role of AVAPS mode with BiPAP spontaneous/timed (S/T) mode for the management of patients with acute exacerbation of COPD with type 2 respiratory failure. Methodology A hospital-based comparative and analytical study was carried out on 100 patients with acute exacerbation of COPD with type 2 respiratory failure admitted to respiratory disease hospital, Sardar Patel Medical College, Bikaner (Rajasthan, India). Patients were randomly divided into two groups of 50 patients each. Group A patients were treated with AVAPS mode and group B patients with BiPAP (S/T) mode. Arterial blood gases, average duration of hospital stay, and need for invasive mechanical ventilation were compared between the two groups. Results There was a statistically significant difference in favor of group A in terms of improvement in pH and pCO₂ as compared to group B at 6 h (pH, p=0.027; pCO₂, p=0.012) and 24 h (pH, p=0.032; pCO₂, p=0.013). The duration of hospital stay was found to be lower in group A (p=0.003). However, no significant difference was found in terms of need for invasive mechanical ventilation between both groups (p=0.338). Conclusion Application of AVAPS mode results in more rapid and steady improvement in patients of COPD as compared to BiPAP (S/T) mode. Thus, management through non-invasive ventilation AVAPS mode should be considered in patients with acute exacerbation of COPD with type 2 respiratory failure.

Cardiovascular autonomic control during application of different modes of noninvasive ventilation in patients affected by amyotrophic lateral sclerosis

BACKGROUND

Cardiovascular events commonly cause death in amyotrophic lateral sclerosis (ALS) even in patients treated by noninvasive ventilation (NIV).

OBJECTIVES

to evaluate autonomic function with the assessment of heart rate variability (HRV) in ALS patients treated by assist pressure control ventilation (APCV) and assist control ventilation (ACV) during sleep.

METHODS

Consecutive ALS patients underwent one polysomnography during APCV and one during ACV. HRV was analyzed both in the total sleep period (from first stage N1 to last awakening) and in a 5-minute period of stable stage N2. Time domain, frequency domain and nonlinear indexes of HRV were measured.

RESULTS

Nineteen patients (age 62.0 ± 8.7, 9F/10 M) were studied. The analysis did not reveal differences in blood gasses between NIV modalities, but a longer expiratory time (3.01±0.6 vs 2.8 ± 0.6 s, respectively APCV vs ACV, p = 0.001) and a lower arousal index (17.5 ± 9.1 vs 23.1 ± 13.9, p = 0.02) during APCV. HRV was indicative of higher vagal activity during APCV, especially in the 5-minute periods. In the total sleep periods, the HRV time domain indexes reflecting parasympathetic activity were positively correlated with the expiratory time and negatively with the inspiratory/expiratory time ratio. Low frequencies were positively, and high frequencies negatively, correlated with inspiratory time. HRV and sleep structure parameters were not correlated, except very low frequencies that were correlated to the arousal index.

CONCLUSIONS

Respiratory influences on autonomic control can be preserved in ALS. The slower breathing pattern during APCV may help to maintain a higher vagal activity. Through this mechanism, in the long-term APCV could more beneficial to ALS patients than ACV.

APAP, BPAP, CPAP, and New Modes of Positive Airway Pressure Therapy

Positive airway pressure (PAP) is the primary treatment of sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. Just as clinicians use pharmacological mechanism of action and pharmacokinetic data to optimize medication therapy for an individual, understanding how PAP works and choosing the right mode and device are critical to optimizing therapy in an individual patient. The first section of this chapter will describe the technology inside PAP devices that is essential for understanding the algorithms used to control the airflow and pressure. The second section will review how different comfort settings including ramp and expiratory pressure relief and modes of PAP therapy including continuous positive airway pressure (CPAP), autotitrating CPAP, bilevel positive airway pressure, adaptive servoventilation, and volume-assured pressure support control the airflow and pressure. Proprietary algorithms from several different manufacturers are described. This chapter derives its descriptions of algorithms from multiple sources including literature review, manufacture publications and websites, patents, and peer-reviewed device comparisons and from personal communication with manufacturer representatives. Clinical considerations related to the technological aspects of the different algorithms and features will be reviewed.

Comparing effectiveness of intelligent volume-assured pressure support (iVAPS) vs bi-level positive airway pressure spontaneous/timed (BPAP S/T) for hypercapnic respiratory failure in chronic obstructive pulmonary disease

BACKGROUND AND AIM

Intelligent volume-assured pressure support (iVAPS) is a relatively new hybrid mode of non-invasive ventilation (NIV). There is still limited evidence for iVAPS. The aim of this study was to compare the effectiveness of iVAPS to that of bi-level positive airway pressure spontaneous/timed (BPAP S/T) in patients with acute hypercapnic respiratory failure or acute-on-chronic hypercapnic respiratory failure caused by acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in the emergency department.

MATERIAL AND METHODS

This was an observational, retrospective study. Eighty-two patients with hypercapnic respiratory failure caused by AECOPD, who were admitted to our emergency department, were analysed. Arterial blood gas (ABG) parameters, length of hospital stay and rate of intensive care unit (ICU) admission were compared between iVAPS and BPAP S/T.

RESULTS

A total of 82 patients (26 females, 56 males, mean age 68.26 ± 11.63 years) who were treated with iVAPS (N = 26) or BPAP S/T (N = 56) were enrolled. There were no significant differences between two modes with respect to demographics such as age, gender, presence of comorbidity, usage of long-term oxygen therapy or NIV, and the baseline ABG parameters. The presence of pneumonia was significantly higher in BPAP S/T (P = .01). The rate of ICU admission was 26.9% in iVAPS vs 25% in BPAP S/T. The mean length of hospital stay was 11.5 ± 12.3 days in iVAPS and 9.7 ± 7.4 days in BPAP S/T (P = .53). The mean values of ABG parameters at the 1st and 24th hours of NIV therapy did not differ in both groups.

CONCLUSION

Both modes were similarly effective in the management of appropriately selected patients with hypercapnic respiratory failure caused by AECOPD. Hence, we underline that NIV mode selection in the emergency department should be performed in line with experiences of clinicians/institutions and accessibility of ventilator devices/modes.

Acute on Chronic Neuromuscular Respiratory Failure in the Intensive Care Unit: Optimization of Triage, Ventilation Modes, and Extubation

Critical care management of acute respiratory failure in patients with neuromuscular disease (NMD) such as amyotrophic lateral sclerosis (ALS) is not standardized and is challenging for many critical care specialists. Progressive hypercapnic respiratory failure and ineffective airway clearance are key issues in this patient population. Often at the time of hospital presentation, patients are already supported by home mechanical ventilatory support with noninvasive ventilation (NIV) and an airway clearance regimen. Prognosis is poor once a patient develops acute respiratory failure requiring intubation and invasive mechanical ventilatory support, commonly leading to tracheostomy or palliative-focused care. 

We focus on this understudied group of patients with ALS without tracheostomy and incorporate existing data to propose a technical approach to the triage and management of acute respiratory failure, primarily for those who require intubation and mechanical ventilatory support for reversible causes, and also for progression of end-stage disease. Optimizing management in this setting improves both quality and quantity of life.

Neuromuscular patients with acute respiratory failure require protocolized and personalized triage and treatment. Here, we describe the technical methods used at our single institution. The triage phase incorporates comprehensive evaluation for new etiologies of hypoxia and hypercapnia, which are not initially presumed to be secondary to progression or end-stage neuromuscular respiratory failure. In select patients, this may involve intubation or advanced adjustments of NIV machines. Next, once the acute etiology(s) is identified and treated, the focus shifts: training and use of mechanical airway clearance to optimize pulmonary function, facilitation of NIV wean or successful extubation to NIV, and transition to a stable regimen for home ventilation. The comprehensive protocol described here incorporates multi-institutional approaches and effectively optimizes acute respiratory failure in patients with neuromuscular pulmonary disease. 

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

Sleep-Disordered Breathing in Patients with Motor Neurone Disease: One Size Does Not Fit all

INTRODUCTION

Sleep-disordered breathing (SDB) in patients with motor neurone disease (MND) is normally attributed to hypoventilation due to muscle weakness. However, we have observed different patterns of SDB among MND patients referred for non-invasive ventilation, which do not appear to be explained by respiratory muscle weakness alone.

AIM

The aim of this study was to examine the characteristics of SDB in MND.

METHODS

This is a retrospective analysis of sleep studies (using polysomnography [PSG]), pulmonary function tests, and arterial blood gases in MND patients referred to a tertiary sleep medicine service for clinical review. Sleep apnoeas were characterised as obstructive or central, and to further characterise the nature of SDB, hypopnoeas were classified as obstructive versus central.

RESULTS

Among 13 MND patients who had a diagnostic PSG, the mean ± SD age was 68.9 ± 9.8 years, BMI 23.0 ± 4.3 kg/m2, forced vital capacity 55.7 ± 20.9% predicted, and partial pressure of CO2 (arterial blood) 52.7 ± 12.1 mm Hg. A total of 38% of patients (5/13) showed evidence of sleep hypoventilation. The total apnoea/hypopnoea index (AHI) was (median [interquartile range]) 44.4(36.2-56.4)/h, with 92% (12/13) showing an AHI >10/h, predominantly due to obstructive events, although 8% (1/13) also showed frequent central apnoea/hypopnoeas.

CONCLUSIONS

Patients with MND exhibit a wide variety of SDB. The prevalence of obstructive sleep apnoea (OSA) is surprising considering the normal BMI in most patients. A dystonic tongue and increased upper-airway collapsibility might predispose these patients to OSA. The wide variety of SDB demonstrated might have implications for ventilator settings and patients' outcomes.

Noninvasive Ventilation in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive neurodegenerative disease involving upper and lower motor neurons and has limited treatment options. The weakness progresses to involve the diaphragms, resulting in respiratory failure and death. Home noninvasive ventilation has been shown to improve survival and quality of life, especially in those with intact bulbar function. Once initiated, close monitoring with nocturnal oximetry, remote downloads from the home noninvasive ventilation machine, and measurement of serum bicarbonate should be conducted. Additionally, transcutaneous CO2 monitoring can be considered if available. This article discusses the indications, timing, initiation, and management of noninvasive ventilation in amyotrophic lateral sclerosis.

Volume-assured pressure support mode for noninvasive ventilation: can it improve overnight adherence in children with neuromuscular disease?

Purpose

Volume-assured pressure support in noninvasive ventilation (VAPS-NIV) is a newer mode providing automatic pressure support adjustment to ensure a constant alveolar ventilation. Previous studies have shown that NIV effectiveness depends on patient adherence and tolerance. The aim of this study was to determine the adherence and efficacy of VAPS-NIV compared to spontaneous-time (S/T) mode in pediatric patients with neuromuscular disease (NMD).

Methods

This was a prospective observational study. Children with NMD who utilized NIV at home for ≥ 3 months were recruited from the Long-term ventilation clinic at The Hospital for Sick Children, Toronto, Canada, from July 1, 2015, to July 1, 2019. Baseline characteristics, date of initiation of NIV, and pulmonary function tests were recorded. Polysomnogram (PSG) data and adherence were recorded and analyzed comparing VAPS and S/T modes.

Results

Twenty children with NMD (17 male, 85%) were enrolled. The mean (SD) age at initiation of NIV was 11.6 ± 4.6 years. The median (IQR) duration of ventilation was 1.36 (0.80–2.98) years. The mean average daily usage and the median daily usage for VAPS mode and S/T mode were 8.4 ± 1.6 versus 7.2 ± 2.5 h (p = 0.012) and 8.6 ± 1.4 versus 7.8 ± 2.1 h (p = 0.022), respectively. There was no difference in sleep architecture, gas exchange, or parent proxy report of NIV tolerance between S/T and VAPS modes.

Conclusion

VAPS was associated with an improvement in adherence to therapy in children with NMD compared to S/T mode. Longitudinal studies are required to evaluate long-term clinical outcomes using VAPS mode in children with NMD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11325-021-02288-1.

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.

Noninvasive volume-assured pressure support for chronic respiratory failure: a review

PURPOSE OF REVIEW

Noninvasive ventilation (NIV) is an established treatment for chronic hypercapnic respiratory failure (CRF). Volume-assured pressure support (VAPS) is a mode of NIV that automatically adjusts inspiratory pressure in order to maintain a constant respiratory volume. We aim to discuss the role and application of VAPS in CRF.

RECENT FINDINGS

Recently published meta-analyses and reviews fail to demonstrate a significant difference in gas exchange, sleep, or quality-of-life improvement between VAPS and bilevel positive airway pressure (BPAP) in patients with CRF. A recent manuscript suggests that VAPS therapy in chronic obstructive pulmonary disease patients may reduce the number of exacerbations. It has been shown that with a protocol-driven approach BPAP and VAPS can both be successfully titrated during a single split-night polysomnography.

SUMMARY

VAPS is as effective as other modes of NIV at improving ventilation and sleep in CRF. The potential advantage is a more consistent ventilatory support through daytime-nighttime variations and progression of disease over time. However, the impact on long-term outcomes, such as survival, has not been studied.

Long-Term Noninvasive Ventilation in the Geneva Lake Area: Indications, Prevalence, and Modalities

BACKGROUND

Noninvasive ventilation (NIV) is standard of care for chronic hypercapnic respiratory failure, but indications, devices, and ventilatory modes are in constant evolution.

RESEARCH QUESTION

To describe changes in prevalence and indications for NIV over a 15-year period; to provide a comprehensive report of characteristics of the population treated (age, comorbidities, and anthropometric data), mode of implementation and follow-up, devices, modes and settings used, physiological data, compliance, and data from ventilator software.

STUDY DESIGN AND METHODS

Cross-sectional observational study designed to include all subjects under NIV followed by all structures involved in NIV in the Cantons of Geneva and Vaud (1,288,378 inhabitants).

RESULTS

A total of 489 patients under NIV were included. Prevalence increased 2.5-fold since 2000 reaching 38 per 100,000 inhabitants. Median age was 71 years, with 31% being > 75 years of age. Patients had been under NIV for a median of 39 months and had an average of 3 ± 1.8 comorbidities; 55% were obese. COPD (including overlap syndrome) was the most important patient group, followed by obesity hypoventilation syndrome (OHS) (26%). Daytime Paco₂ was most often normalized. Adherence to treatment was satisfactory, with 8% only using their device < 3.5 h/d. Bilevel positive pressure ventilators in spontaneous/timed mode was the default mode (86%), with a low use of autotitrating modes. NIV was initiated electively in 50% of the population, in a hospital setting in 82%, and as outpatients in 15%.

INTERPRETATION

Use of NIV is increasing rapidly in this area, and the population treated is aging, comorbid, and frequently obese. COPD is presently the leading indication followed by OHS.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT04054570; URL: www.clinicaltrials.gov.

Effect of average volume-assured pressure support treatment on health-related quality of life in COPD patients with chronic hypercapnic respiratory failure: a randomized trial

The long-term effect of average volume-assured pressure support (AVAPS) on health-related quality of life (HRQOL) in chronic obstructive pulmonary disease (COPD) patients with chronic hypercapnic respiratory failure (CHRF) remains unclear. The objective of this study is to identify the long-term effect of AVAPS in COPD patients with CHRF through assessment of HRQOL, exercise tolerance after six months duration.

METHODS

In this randomized, controlled, parallel-group study, 40 stable hypercapnic COPD patients were randomized in a 1:1 ratio to receive either spontaneous timed AVAPS (ST/AVAPS) (intervention) or Bilevel positive airway pressure (ST/BiPAP) (control). HRQL was measured with the Short Form 12 Health Survey Questionnaire (SF-12). Exercise tolerance assessed by 6 min walking distance. Analyses were done between groups from baseline to the average of six months measurements.

RESULTS

AVAPS led to significant 6 months improvements in several domains of (SF-12) compared to the control group, with the greatest improvement seen in general health [treatment effect of 8.2 points (95% confidence interval [95% CI 3.2 to 11.7; p = 0.001)], vitality (treatment effect 5.4 points [95% CI 1.4 to 9.3]; p = 0.001), physical functioning 5.5 points [95% CI 1.1 to 9.8]; p = 0.001) and bodily pain 5.1 points [95% CI 3.4 to 8.8]; p = 0.002). The physical health summary score improved by 3.7 points (95% CI 1.2 to 5.8; p = 0.001), but no significant improvement in the emotional or social role functioning, mental health subscale was noted. AVAPS also resulted in improvement 6 min walking distance 9.2 points (95% CI - 1 to - 15];p = 0.001). A significant reduction in the daytime (PaCO2) was observed after 6 months in those treated with AVAPS.

CONCLUSIONS

In COPD patients with hypercapnic respiratory failure, AVAPS improved exercise tolerance and multiple domains of HRQOL over six months of follow-up, with the significant improvement observed in general health.

Automatic EPAP intelligent volume-assured pressure support is effective in patients with chronic respiratory failure: A randomized trial

BACKGROUND AND OBJECTIVE

Patients with chronic respiratory failure are increasingly managed with domiciliary non-invasive ventilation (NIV). There may be limited ability to provide NIV titration for these complex patients, and ventilatory requirements and upper airway support needs may change over time. Therefore, an automatically adjusting expiratory positive airway pressure (AutoEPAP) algorithm may offer advantages over manually adjusted EPAP for treating these patients. This study compared 4% oxygen desaturation index (ODI4%) values during the use of an AutoEPAP algorithm versus manual EPAP titration with the intelligent volume-assured pressure support (iVAPS) algorithm.

METHODS

This prospective, single-blind, randomized, crossover study was conducted at six US sites. Patients with chronic respiratory failure (neuromuscular disease, chronic obstructive pulmonary disease, obesity hypoventilation and other aetiologies) and an apnoea-hypopnoea index of >5/h who were already established NIV users underwent a single night of NIV with the iVAPS manual EPAP and iVAPS AutoEPAP in the sleep laboratory in random order.

RESULTS

A total of 38 patients constituted the study population. Mean ODI4% was statistically non-inferior with AutoEPAP versus manual EPAP (P < 0.0001). There was no difference in the effect on ODI4% across respiratory failure subgroups. Ventilation parameters and gas exchange were similar with either NIV mode, indicating equally effective treatment of respiratory failure. Sleep parameters were improved during AutoEPAP versus manual EPAP.

CONCLUSION

A single night of NIV using the iVAPS with AutoEPAP algorithm was non-inferior to a single night of iVAPS with manual EPAP titration in patients with respiratory failure.

CLINICAL TRIAL REGISTRATION

NCT02683772 at clinicaltrials.gov.

Obesity hypoventilation syndrome

Obesity hypoventilation syndrome (OHS) is defined as a combination of obesity (body mass index ≥30 kg·m-2), daytime hypercapnia (arterial carbon dioxide tension ≥45 mmHg) and sleep disordered breathing, after ruling out other disorders that may cause alveolar hypoventilation. OHS prevalence has been estimated to be ∼0.4% of the adult population. OHS is typically diagnosed during an episode of acute-on-chronic hypercapnic respiratory failure or when symptoms lead to pulmonary or sleep consultation in stable conditions. The diagnosis is firmly established after arterial blood gases and a sleep study. The presence of daytime hypercapnia is explained by several co-existing mechanisms such as obesity-related changes in the respiratory system, alterations in respiratory drive and breathing abnormalities during sleep. The most frequent comorbidities are metabolic and cardiovascular, mainly heart failure, coronary disease and pulmonary hypertension. Both continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV) improve clinical symptoms, quality of life, gas exchange, and sleep disordered breathing. CPAP is considered the first-line treatment modality for OHS phenotype with concomitant severe obstructive sleep apnoea, whereas NIV is preferred in the minority of OHS patients with hypoventilation during sleep with no or milder forms of obstructive sleep apnoea (approximately <30% of OHS patients). Acute-on-chronic hypercapnic respiratory failure is habitually treated with NIV. Appropriate management of comorbidities including medications and rehabilitation programmes are key issues for improving prognosis.

Long-Term Ventilation in Neuromuscular Patients: Review of Concerns, Beliefs, and Ethical Dilemmas

BACKGROUND

Noninvasive mechanical ventilation (NIV) is an effective treatment in patients with neuromuscular diseases (NMD) to improve symptoms, quality of life, and survival.

SUMMARY

NIV should be used early in the course of respiratory muscle involvement in NMD patients and its requirements may increase over time. Therefore, training on technical equipment at home and advice on problem solving are warranted. Remote monitoring of ventilator parameters using built-in ventilator software is recommended. Telemedicine may be helpful in reducing hospital admissions. Anticipatory planning and palliative care should be carried out to lessen the burden of care, to maintain or withdraw from NIV, and to guarantee the most respectful management in the last days of NMD patients' life. Key Message: Long-term NIV is effective but challenging in NMD patients. Efforts should be made by health care providers in arranging a planned transition to home and end-of-life discussions for ventilator-assisted individuals and their families.

Noninvasive auto-titrating ventilation (AVAPS-AE) versus average volume-assured pressure support (AVAPS) ventilation in hypercapnic respiratory failure patients

Auto-titrating noninvasive ventilation (NIV) has been developed as a new mode applying variable expiratory-positive airway pressure (EPAP) in addition to variable inspiratory pressures (IPAP), both to deliver targeted tidal volume (VT) and to eliminate upper airway resistance. The purpose of this study is to evaluate whether NIV with auto-titrating mode will decrease more PaCO₂ within a shorter time compared to volume-assured mode in hypercapnic intensive care unit (ICU) patients. The hypercapnic respiratory failure patients treated with average volume assured pressure support- automated EPAP mode (group1) were compared with those treated with average volume-assured pressure support mode (group2). Two groups were matched with each other according to baseline diagnoses, demographic characteristics, arterial blood gas values, target VT settings and daily NIV usage times. Built-in software was used to gather the ventilatory parameters. Twenty-eight patients were included in group 1, and 22 in group 2. The decrease in PaCO₂ had been achieved within a shorter time period in group 1 (p < 0.05). This response was more pronounced within the first 6 h (mean reduction in PaCO₂ was 7 ± 7 mmHg in group 1 and 2 ± 5 mmHg in group 2, p = 0.025), and significantly greater reductions in PaCO₂ (18 ± 11 mmHg in group 1 and 9 ± 8 mmHg in group 2, p = 0.008) and plasma HCO₃ levels (from 32 to 30 mEq and from 35 to 35 mEq, p = 0.007) took place within first 4 days. While mean IPAP was similar in both groups, maximum EPAP, mean VT and leak were significantly higher in group 1 than in group 2 (p < 0.05). Results of this preliminary study suggest that, this new auto-titrating NIV mode may provide additional benefit on volume-assured mode in decreasing PaCO₂ more efficiently and rapidly in hypercapnic ICU patients.

Treating Chronic Hypoventilation With Automatic Adjustable Versus Fixed EPAP Intelligent Volume-Assured Positive Airway Pressure Support (iVAPS): A Randomized Controlled Trial

Objectives

New noninvasive ventilation (NIV) modes can automatically adjust pressure support settings to deliver effective ventilation in response to varying ventilation demands. It is recommended that fixed expiratory positive airway pressure (FixedEPAP) is determined by attended laboratory polysomnographic (PSG) titration. This study investigated whether automatically determined EPAP (AutoEPAP) was noninferior to FixedEPAP for the control of obstructive sleep apnea (OSA) during intelligent volume-assured pressure support (iVAPS) treatment of chronic hypoventilation.

Methods

In this randomized, double-blind, crossover study, patients with chronic hypoventilation and OSA used iVAPS with AutoEPAP or FixedEPAP over two separate nights of attended PSG. PSG recordings were scored by an independent scorer using American Academy of Sleep Medicine 2012 criteria.

Results

Twenty-five adults (14 male) with chronic hypoventilation secondary to obesity hypoventilation syndrome (n = 11), chronic obstructive pulmonary disease (n = 9), or neuromuscular disease (n = 5), all of whom were on established home NIV therapy, were included (age 57 ± 7 years, NIV for ≥3 months, apnea-hypopnea index [AHI] >5/hour). AutoEPAP was noninferior to FixedEPAP for the primary outcome measure (median [interquartile range] AHI 2.70 [1.70-6.05]/hour vs. 2.40 [0.25-5.95]/hour; p = .86). There were no significant between-mode differences in PSG sleep breathing and sleep quality, or self-reported sleep quality, device comfort, and patient preference. Mean EPAP with the Auto and Fixed modes was 10.8 ± 2.0 and 11.8 ± 3.9 cmH2O, respectively (p = .15).

Conclusions

In patients with chronic hypoventilation using iVAPS, the AutoEPAP algorithm was noninferior to FixedEPAP over a single night's therapy.

Positive Airway Pressure Device Technology Past and Present: What's in the "Black Box"?

Since the introduction of continuous positive airway pressure (PAP) for the treatment of obstructive sleep apnea (OSA) in 1981, PAP technology has diversified exponentially. Compact and quiet fixed continuous PAP flow generators, autotitrating PAP devices, and bilevel PAP devices that can treat multiple sleep-disordered breathing phenotypes including OSA, central sleep apnea (CSA), combinations of OSA and CSA, and hypoventilation are available. Adaptive servo-ventilators can suppress Hunter-Cheyne-Stokes breathing and CSA and treat coexisting obstructive events. Volume-assured pressure support PAP apparatus purports to provide a targeted degree of ventilatory assistance while also treating cooccurring OSA and/or CSA.

AJRCCM: 100-Year Anniversary. Homeward Bound: A Centenary of Home Mechanical Ventilation

The evolution of home mechanical ventilation is an intertwined chronicle of negative and positive pressure modes and their role in managing ventilatory failure in neuromuscular diseases and other chronic disorders. The uptake of noninvasive positive pressure ventilation has resulted in widespread growth in home ventilation internationally and fewer patients being ventilated invasively. As with many applications of domiciliary medical technology, home ventilatory support has either led or run in parallel with acute hospital applications and has been influenced by medical and societal shifts in the approach to chronic care, the creation of community support teams, a preference of recipients to be treated at home, and economic imperatives. This review summarizes the trends and growing evidence base for ventilatory support outside the hospital.

Long-term volume-targeted pressure-controlled ventilation: sense or nonsense?

The technology underlying the development of novel ventilatory modes for long-term noninvasive ventilation of patients with chronic hypercapnia is continuously evolving. Volume-targeted pressure-controlled ventilation is a hybrid ventilation mode designed to combine the advantages of conventional ventilation modes, while avoiding their drawbacks. However, manufacturers have created different names and have patented algorithms and set-up variables, which can result in confusion for physicians and respiratory therapists. In addition, clear evidence for the superiority of this novel mode has not yet been established. These factors have most likely hindered more widespread use of this mode in clinical practice. The current review presents the rationale, working principles, characteristics and set-up recommendations associated with volume-targeted modes. In addition, it summarises the clinical and laboratory studies that have challenged this mode.

Sleep-Disordered Breathing in Neuromuscular Disease: Diagnostic and Therapeutic Challenges

Normal sleep-related rapid eye movement sleep atonia, reduced lung volumes, reduced chemosensitivity, and impaired airway dilator activity become significant vulnerabilities in the setting of neuromuscular disease. In that context, the compounding effects of respiratory muscle weakness and disease-specific features that promote upper airway collapse or cause dilated cardiomyopathy contribute to various sleep-disordered breathing events. The reduction in lung volumes with neuromuscular disease is further compromised by sleep and the supine position, exaggerating the tendency for upper airway collapse and desaturation with sleep-disordered breathing events. The most commonly identified events are diaphragmatic/pseudo-central, due to a decrease in the rib cage contribution to the tidal volume during phasic rapid eye movement sleep. Obstructive and central sleep apneas are also common. Noninvasive ventilation can improve survival and quality of sleep but should be used with caution in the context of dilated cardiomyopathy or significant bulbar symptoms. Noninvasive ventilation can also trigger sleep-disordered breathing events, including ineffective triggering, autotriggering, central sleep apnea, and glottic closure, which compromise the potential benefits of the intervention by increasing arousals, reducing adherence, and impairing sleep architecture. Polysomnography plays an important diagnostic and therapeutic role by correctly categorizing sleep-disordered events, identifying sleep-disordered breathing triggered by noninvasive ventilation, and improving noninvasive ventilation settings. Optimal management may require dedicated hypoventilation protocols and a technical staff well versed in the identification and troubleshooting of respiratory events.

Intelligent volume-assured pressured support (iVAPS) for the treatment of congenital central hypoventilation syndrome

PURPOSE

Congenital central hypoventilation syndrome (CCHS) is characterized by ventilatory insensitivity to hypercapnia and hypoxemia during sleep and/or wakefulness. Management of CCHS includes a long-term ventilation. However, ventilation can be challenging given differences in the control of breathing during different sleep stages. Intelligent volume-assured pressure support (iVAPS) is a mode of Bi-level positive airway pressure (BPAP) ventilation in which the pressure support is modulated to ensure a constant alveolar ventilation. The aim of this study was to determine if BPAP with iVAPS mode is more effective at controlling hypercapnia than BPAP with spontaneous/timed (S/T) mode.

METHODS

A retrospective chart review of CCHS patients who underwent both a titration polysomnogram (PSG) with standard BPAP S/T mode and a consecutive follow-up study with BPAP iVAPS mode at The Hospital for Sick Children, Toronto, Canada, between January 1, 2013 and September 30, 2015 were included. Comparisons were made between S/T mode and iVAPS mode.

RESULTS

Eight (four males) children with CCHS were included. The median (IQR) age at the time of PSG using Bi-level ventilation with S/T mode for study participants was 10.0 (IQR 8.4, 11.6) years followed by PSGs with iVAPS mode, median age 10.6 (IQR 9.1, 12.5) years. The non-rapid eye movement (NREM) peak transcutaneous CO₂ (tcCO₂) median (IQR) for iVAPS was 43.0 (40.0-46.0-) mmHg versus 46.5 (45.0-48.0) mmHg for S/T mode, (p value <0.05).

CONCLUSION

iVAPS was associated with a reduction in the maximum tcCO2 during NREM sleep as compared to traditional S/T mode. Prospective, longitudinal studies are needed to evaluate the benefits of BPAP therapy iVAPS mode for the treatment of pediatric CCHS.

Advanced positive airway pressure modes: adaptive servo ventilation and volume assured pressure support

INTRODUCTION

Volume assured pressure support (VAPS) and adaptive servo ventilation (ASV) are non-invasive positive airway pressure (PAP) modes with sophisticated negative feedback control systems (servomechanism), having the capability to self-adjust in real time its respiratory controlled variables to patient's respiratory fluctuations. However, the widespread use of VAPS and ASV is limited by scant clinical experience, high costs, and the incomplete understanding of propriety algorithmic differences in devices' response to patient's respiratory changes. Hence, we will review and highlight similarities and differences in technical aspects, control algorithms, and settings of each mode, focusing on the literature search published in this area.

AREAS COVERED

One hundred twenty relevant articles were identified by Scopus, PubMed, and Embase databases from January 2010 to 2016, using a combination of MeSH terms and keywords. Articles were further supplemented by pearling. Recommendations were based on the literature review and the authors' expertise in this area. Expert commentary: ASV and VAPS differ in their respiratory targets and response to a respiratory fluctuation. The VAPS mode targets a more consistent minute ventilation, being recommended in the treatment of sleep related hypoventilation disorders, while ASV mode attempts to provide a more steady breathing airflow pattern, treating successfully most central sleep apnea syndromes.

Domiciliary noninvasive positive airway pressure therapy in children

There has been a dramatic increase in the past few decades in the number of children receiving noninvasive positive airway pressure (PAP) therapy at home. Although PAP therapy was first prescribed for children with obstructive sleep apnea, the indications have rapidly widened to include treatment for central hypoventilation syndromes, neuromuscular and chest wall disorders as well as primary respiratory diseases. Given the rapidly expanding use of PAP therapy in children, pediatric pulmonologists need to be familiar with the indications, technical and safety considerations as well as potential complications and challenges that may arise when caring for children using PAP therapy. This review article covers the definition of PAP therapy, modes, interfaces, devices, indications, contraindications, suggested settings, complications as well as the factors influencing the adherence.

Advances and New Approaches to Managing Sleep-Disordered Breathing Related to Chronic Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a common disease affecting about 20 million US adults. Sleep-disordered breathing (SDB) problems are frequent and poorly characterized for patients with COPD. Both the well-known success of noninvasive ventilation (NIV) in the acute COPD exacerbation in the hospital setting and that NIV is the cornerstone of chronic therapy for SDBs have urged the attention of the medical community to determine the impact of NIV on chronic COPD management with and without coexisting SDBs. Early observational studies showed decreased long-term survival rates on patients with COPD with concomitant chronic hypercapnia when compared with normocapnic patients.

New modes in non-invasive ventilation

Non-invasive ventilation is useful to treat some forms of respiratory failure. Hence, the number of patients receiving this treatment is steadily increasing. Considerable conceptual and technical progress has been made in the last years by manufacturers concerning this technique. This includes new features committed to improve its effectiveness as well as patient-ventilator interactions. The goal of this review is to deal with latest advances in ventilatory modes and features available for non-invasive ventilation. We present a comprehensive analysis of new modes of ventilator assistance committed to treat respiratory failure (hybrid modes) and central and complex sleep apnea (adaptive servo ventilation), and of new modes of triggering and cycling (neurally adjusted ventilatory assist). Technical aspects, modes of operation and settings of these new features as well as an exhaustive review of published data, their benefits and limits, and the potential place of these devices in clinical practice, are discussed.

Update on clinical trials in home mechanical ventilation

Home mechanical ventilation (HMV) is an increasingly common intervention and is initiated for a range of pathological processes, including neuromuscular disease (NMD), chronic obstructive pulmonary disease (COPD) and obesity related respiratory failure. There have been important recent data published in this area, which helps to guide practice by indicating which populations may benefit from this intervention and the optimum method of setting up and controlling sleep disordered breathing. Recent superficially conflicting data has been published regarding HMV in COPD, with a trial in post-exacerbation patients suggesting no benefit, but in stable chronic hypercapnic patients suggesting a clear and sustained mortality benefit. The two studies are critiqued and the potential reasons for the differing results are discussed. Early and small trial data is frequently contradicted with larger randomised controlled trials and this has been the case with diaphragm pacing being shown to be potentially harmful in the latest data, confirming the importance of non-invasive ventilation (NIV) in NMD such as motor neurone disease. Advances in ventilator technology have so far appeared quicker than the clinical data to support their use; although small and often unblinded, the current data suggests equivalence to standard modes of NIV, but with potential comfort benefits that may enhance adherence. The indications for NIV have expanded since its inception, with an effort to treat sleep disordered breathing as a result of chronic heart failure (HF). The SERVE-HF trial has recently demonstrated no clear advantage to this technology and furthermore detected a potentially deleterious effect, with a worsening of all cause and cardiovascular mortality in the treated group compared to controls. The review serves to provide the reader with a critical review of recent advances in the field of sleep disordered breathing and HMV.

The use of volume-assured pressure support noninvasive ventilation in acute and chronic respiratory failure: a practical guide and literature review

Noninvasive positive pressure ventilation (NPPV) is an important tool in the management of acute and chronic respiratory failure. Traditionally, continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) have been the most commonly utilized modes for these purposes. Newer hybrid modes of NPPV, such as average volume-assured pressure support (VAPS), combine the properties of both volume- and pressure-controlled NPPV and represent another tool in the treatment of acute and chronic respiratory failure. Evidence demonstrating the superiority of VAPS over BPAP is sparse, but there have been studies that have demonstrated comparable efficacy between the two modes. The use of VAPS in acute hypercapnic respiratory failure has shown better clearance of CO2 compared to BPAP, due to its property of delivering a more assured tidal volume. This, however, did not lead to a decrease in hospital-days or improved mortality, relative to BPAP. The studies evaluating VAPS for chronic respiratory failure involve small sample sizes but have shown some promise. The benefits noted with VAPS, however, did not translate into increased survival, decreased hospitalizations or improved quality of life compared to BPAP. The limited evidence available suggests that VAPS is equally effective in treating acute and chronic respiratory failure compared to BPAP. Overall, the evidence to suggest superiority of one mode over the other is lacking. There is a need for larger studies before firm conclusions can be made.

Treatment of sleep-disordered breathing with positive airway pressure devices: technology update

Many types of positive airway pressure (PAP) devices are used to treat sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. These include continuous PAP, autoadjusting CPAP, bilevel PAP, adaptive servoventilation, and volume-assured pressure support. Noninvasive PAP has significant leak by design, which these devices adjust for in different manners. Algorithms to provide pressure, detect events, and respond to events vary greatly between the types of devices, and vary among the same category between companies and different models by the same company. Many devices include features designed to improve effectiveness and patient comfort. Data collection systems can track compliance, pressure, leak, and efficacy. Understanding how each device works allows the clinician to better select the best device and settings for a given patient. This paper reviews PAP devices, including their algorithms, settings, and features.

Obesity Hypoventilation Syndrome

Obesity hypoventilation syndrome is a respiratory consequence of morbid obesity that is characterized by alveolar hypoventilation during sleep and wakefulness. The disorder involves a complex interaction between impaired respiratory mechanics, ventilatory drive and sleep-disordered breathing. Early diagnosis and treatment is important, because delay in treatment is associated with significant mortality and morbidity. Available treatment options include non-invasive positive airway pressure (PAP) therapies and weight loss. There is limited long-term data regarding the effectiveness of such therapies. This review outlines the current concepts of clinical presentation, diagnostic and management strategies to help identify and treat patients with obesity-hypoventilation syndromes.

Positive airway pressure therapy for heart failure

Heart failure (HF) is a life-threatening disease and is a growing public health concern. Despite recent advances in pharmacological management for HF, the morbidity and mortality from HF remain high. Therefore, non-pharmacological approaches for HF are being developed. However, most non-pharmacological approaches are invasive, have limited indication and are considered only for advanced HF. Accordingly, the development of less invasive, non-pharmacological approaches that improve outcomes for patients with HF is important. One such approach may include positive airway pressure (PAP) therapy. In this review, the role of PAP therapy applied through mask interfaces in the wide spectrum of HF care is discussed.

Advances in Positive Airway Pressure Treatment Modalities for Hypoventilation Syndromes

RATIONALE

Positive airway pressure therapy for hypoventilation syndromes can significantly improve health-related quality of life (HR-QOL), healthcare costs, and even mortality. The sleep-disordered breathing in such individuals are quite complex and require sophisticated devices with algorithms that are designed to accurately detect and effectively treat respiratory events that includes hypoventilation, upper airway obstruction, lower airway obstruction, central apneas and central hypopneas and reduce the work of breathing while maintaining breathing comfort.

OBJECTIVES

The therapeutic physiological rationale for the various advanced PAP modalities and the details about the principles of operation and technology implementation are provided here.

CONCLUSIONS

The physiological rationale for advanced PAP modalities is sound considering the complexity of sleep-disordered breathing in patients with hypoventilation syndromes. Although such devices are increasingly used in clinical practice, the supporting clinical evidence - specifically comparative-effectiveness studies in real-life conditions -- needs to be performed. Moreover, there is much opportunity for further refining these devices that include the ability of the device to reliably monitor gas-exchange, sleep-wakefulness state, and for reducing variability in device efficacy due to provider-selected device-settings.