Usefulness of transcutaneous PCO2to assess nocturnal hypoventilation in restrictive lung disorders

Clinical correlates of respiratory disorders in patients with severe multiple sclerosis: A cross-sectional cohort

BACKGROUND

Respiratory disorders remain incompletely described in multiple sclerosis (MS), even though they are a frequent cause of death.

METHODS

The objective was to describe respiratory disorders in MS patients with Expanded Disability Status Score (EDSS) ⩾ 6.5. Diaphragm dysfunction was defined by at least two of the seven criteria: clinical signs, inspiratory recruitment of neck muscles during wakefulness, reduced upright vital capacity (VC) < 80%, upright-to-supine VC ⩾ 15% of upright VC, decrease in Maximal Inspiratory Pressure < 60%, phasic activation of inspiratory neck muscles during sleep, and opposition of thoracic and abdominal movements during sleep. Cough weakness was defined by a peak cough flow < 270 L/min and/or need for cough assist. Sleep apnea syndrome was defined by an apnea-hypopnea index ⩾ 15.

RESULTS

Notably, 71 MS patients were included: median age 54 [48, 61] years; median disease duration 21.4 [16.0, 31.4] years. Of these, 52 patients had one or more respiratory disorders; diaphragm dysfunction was the most frequent (n = 34). Patients with diaphragm dysfunction and cough weakness were more disabled. The fatigue score and the cognitive evaluations did not differ between the groups. Five patients required non-invasive ventilation.

CONCLUSION

Respiratory disorders are frequent in severe MS, mostly diaphragm dysfunction. Of interest, instrumental interventions are available to address these disorders.

Sleep disordered breathing assessment in patient with slowly progressive neuromuscular disease

BACKGROUND

Sleep-disordered breathing (SDB) is common in patients with neuromuscular diseases (NMD). Focusing on hypercapnia may lead to the neglect of other SDB such as obstructive and/or central sleep apnea syndrome (SAS). Our objectives were to assess the risk of inappropriate SDB management according to different screening strategies and to evaluate the prevalence and determinants of isolated and overlapping sleep apnea in patients with slowly progressive NMD.

METHODS

This monocentric, cross-sectional, retrospective study analyzed medical records of adult NMD patients referred to a sleep department. Diagnostic strategies, including respiratory polygraphy (RP), nocturnal transcutaneous capnography (tcCO2), and blood gases (BG), were assessed for their performance in diagnosing SDB. Demographics and pulmonary function test results were compared between patients with or without SDB to identify predictors.

RESULTS

Among the 149 patients who underwent a full diagnostic panel (RP + tcCO2 + BG), 109 were diagnosed with SDB. Of these, 33% had isolated SAS, and central apneas were predominant. Using single diagnostic strategies would lead to inappropriate SDB management in two thirds of patients. A combination of 2 diagnostic tools resulted respectively in 21.1, 22.9 and 42.2 % of inappropriate SDB management for RP + tcCO2, RP + BG and tcCO2 + BG.

CONCLUSION

The significant prevalence of sleep apnea syndrome in patients with slowly progressive NMD highlights the need for increased awareness among clinicians. Improved diagnostics involve a systematic approach addressing both sleep apnea and diurnal and nocturnal alveolar hypoventilation to avoid inappropriate management and limit the consequences of SDB.

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.

Pulmonary care for ALS: Progress, gaps, and paths forward

INTRODUCTION

Adults with amyotrophic lateral sclerosis (ALS) have been using home mechanical ventilation for over 50 years. More recently, home respiratory care has evolved to include portable home ventilators, airway clearance devices, and physiological assessments with telemonitoring capability.

CURRENT STATE OF RESPIRATORY CARE

National organizations currently offer incentives for providing a pulmonary care specialist within a multidisciplinary ALS clinic; however, several critical gaps exist between the available technology and employing a clinician with the necessary expertise.

GAPS IN CARE

Lack of formal training and poor financial incentives have led to a paucity of both clinicians and active clinical research engaging in the home respiratory care of ALS. Criteria for noninvasive ventilation (NIV) initiation are controversial, and few guidelines exist on the ideal subsequent adjustments of NIV with evolving disease. Consequently, many patients with ALS tolerate NIV poorly and must face the harrowing decision of hospice vs tracheostomy. Advancement of respiratory care in ALS has been hindered by critical gaps in pulmonologist availability, training in chronic respiratory failure, financial support, clinical research, and clarity on ventilation management beyond initiation.

BRINGING RESPIRATORY CARE UP TO SPEED

Only a multifaceted approach will suffice for addressing the voids in ALS respiratory care, including various education initiatives, financial incentives, clinical research programs, and elevating the standard of respiratory care.

Moving from Inpatient to Outpatient or Home Initiation of Non-Invasive Home Mechanical Ventilation

Home mechanical ventilation (HMV) is an effective treatment for patients with chronic hypercapnic respiratory failure caused by restrictive or obstructive pulmonary disorders. Traditionally, HMV is initiated in the hospital, nowadays usually on a pulmonary ward. The success of HMV, and especially non-invasive home mechanical ventilation (NIV), has led to a steep and ongoing increase in the incidence and prevalence of HMV, in particular for patients with COPD or obesity hypoventilation syndrome. Consequently, the number of available hospital beds to accommodate these patients has become insufficient, and models of care that minimize the use of (acute) hospital beds need to be developed. At present, the practices for initiation of NIV vary widely, reflecting the limited research on which to base model-of-care decisions, local health system features, funding models, and historical practices. Hence, the opportunity to establish outpatient and home initiation may differ between countries, regions, and even HMV centres. In this narrative review, we will describe the evidence regarding the feasibility, effectiveness, safety, and cost savings of outpatient and home initiation of NIV. In addition, the benefits and challenges of both initiation strategies will be discussed. Finally, patient selection and execution of both approaches will be examined.

Monitoring Systems in Home Ventilation

Non-invasive ventilation (NIV) is commonly used at home for patient with nocturnal hypoventilation caused by a chronic respiratory failure. Monitoring NIV is required to optimize the ventilator settings when the lung condition changes over time, and to detect common problems such as unintentional leaks, upper airway obstructions, and patient–ventilator asynchronies. This review describes the accuracy and limitations of the data recorded by the ventilator. To efficiently interpret this huge amount of data, clinician assess the daily use and regularity of NIV utilization, the unintentional leaks and their repartition along the NIV session, the apnea–hypopnea index and the flow waveform, and the patient–ventilator synchrony. Nocturnal recordings of gas exchanges are also required to detect nocturnal alveolar hypoventilation. This review describes the indication, validity criteria, and interpretation of nocturnal oximetry and transcutaneous capnography. Polygraphy and polysomnography are indicated in specific cases to characterize upper airway obstruction. Telemonitoring of the ventilator is a useful tool that should be integrated in the monitoring strategy. The technical solution, information, and limitations are discussed. In conclusion, a basic monitoring package is recommended for all patients complemented by advanced monitoring for specific cases.

Monitoring Long Term Noninvasive Ventilation: Benefits, Caveats and Perspectives

Long term noninvasive ventilation (LTNIV) is a recognized treatment for chronic hypercapnic respiratory failure (CHRF). COPD, obesity-hypoventilation syndrome, neuromuscular disorders, various restrictive disorders, and patients with sleep-disordered breathing are the major groups concerned. The purpose of this narrative review is to summarize current knowledge in the field of monitoring during home ventilation. LTNIV improves symptoms related to CHRF, diurnal and nocturnal blood gases, survival, and health-related quality of life. Initially, patients with LTNIV were most often followed through elective short in-hospital stays to ensure patient comfort, correction of daytime blood gases and nocturnal oxygenation, and control of nocturnal respiratory events. Because of the widespread use of LTNIV, elective in-hospital monitoring has become logistically problematic, time consuming, and costly. LTNIV devices presently have a built-in software which records compliance, leaks, tidal volume, minute ventilation, cycles triggered and cycled by the patient and provides detailed pressure and flow curves. Although the engineering behind this information is remarkable, the quality and reliability of certain signals may vary. Interpretation of the curves provided requires a certain level of training. Coupling ventilator software with nocturnal pulse oximetry or transcutaneous capnography performed at the patient's home can however provide important information and allow adjustments of ventilator settings thus potentially avoiding hospital admissions. Strategies have been described to combine different tools for optimal detection of an inefficient ventilation. Recent devices also allow adapting certain parameters at a distance (pressure support, expiratory positive airway pressure, back-up respiratory rate), thus allowing progressive changes in these settings for increased patient comfort and tolerance, and reducing the requirement for in-hospital titration. Because we live in a connected world, analyzing large groups of patients through treatment of “big data” will probably improve our knowledge of clinical pathways of our patients, and factors associated with treatment success or failure, adherence and efficacy. This approach provides a useful add-on to randomized controlled studies and allows generating hypotheses for better management of HMV.

Proposals from a French expert panel for respiratory care in ALS patients

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive diaphragm weakness and deteriorating lung function. Bulbar involvement and cough weakness contribute to respiratory morbidity and mortality. ALS-related respiratory failure significantly affects quality of life and is the leading cause of death. Non-invasive ventilation (NIV), which is the main recognized treatment for alleviating the symptoms of respiratory failure, prolongs survival and improves quality of life. However, the optimal timing for the initiation of NIV is still a matter of debate. NIV is a complex intervention. Multiple factors influence the efficacy of NIV and patient adherence. The aim of this work was to develop practical evidence-based advices to standardize the respiratory care of ALS patients in French tertiary care centres.

METHODS

For each proposal, a French expert panel systematically searched an indexed bibliography and prepared a written literature review that was then shared and discussed. A combined draft was prepared by the chairman for further discussion. All of the proposals were unanimously approved by the expert panel.

RESULTS

The French expert panel updated the criteria for initiating NIV in ALS patients. The most recent criteria were established in 2005. Practical advice for NIV initiation were included and the value of each tool available for NIV monitoring was reviewed. A strategy to optimize NIV parameters was suggested. Revisions were also suggested for the use of mechanically assisted cough devices in ALS patients.

CONCLUSION

Our French expert panel proposes an evidence-based review to update the respiratory care recommendations for ALS patients in daily practice.

Respiratory Muscle Function Tests and Diaphragm Ultrasound Predict Nocturnal Hypoventilation in Slowly Progressive Myopathies

Introduction: In slowly progressive myopathies, diaphragm weakness early manifests through sleep-related hypoventilation as reflected by nocturnal hypercapnia. This study investigated whether daytime tests of respiratory muscle function and diaphragm ultrasound predict hypercapnia during sleep.

Methods: Twenty-seven patients with genetic myopathies (myotonic dystrophy type 1 and 2, late-onset Pompe disease, facioscapulohumeral dystrophy; 48 ± 11 years) underwent overnight transcutaneous capnometry, spirometry, measurement of mouth occlusion pressures, and diaphragm ultrasound.

Results: Sixteen out of 27 patients showed nocturnal hypercapnia (peak p_tcCO₂ ≥ 50 mmHg for ≥ 30 min or increase in p_tcCO₂ by 10 mmHg or more from the baseline value). In these patients, forced vital capacity (FVC; % predicted) and maximum inspiratory pressure (MIP; % of lower limit or normal or LLN) were significantly reduced compared to normocapnic individuals. Nocturnal hypercapnia was predicted by reduction in FVC of <60% [sensitivity, 1.0; area under the curve (AUC), 0.82] and MIP (%LLN) <120% (sensitivity, 0.83; AUC, 0.84), the latter reflecting that in patients with neuromuscular disease, pretest likelihood of abnormality is per se higher than in healthy subjects. Diaphragm excursion velocity during a sniff maneuver excluded nocturnal hypercapnia with high sensitivity (0.90) using a cutoff of 8.0 cm/s.

Conclusion: In slowly progressive myopathies, nocturnal hypercapnia is predicted by FVC <60% or MIP <120% (LLN). As a novelty, nocturnal hypercapnia can be excluded with acceptable sensitivity by diaphragm excursion velocity >8.0 cm/s on diaphragm ultrasound.

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.

Hypoventilation syndrome in neuromuscular disorders

PURPOSE OF REVIEW

Hypoventilation syndrome in neuromuscular disorders (NMDs) is primarily due to respiratory muscle weakness and results in increased morbidity and mortality. This article highlights current aspects of neuromuscular hypoventilation syndrome, including pathophysiology, clinical symptoms, assessment, respiratory involvement in various NMD, and causal and symptomatic treatments with an emphasis on recent research and advances.

RECENT FINDINGS AND SUMMARY

New therapeutic agents have been developed within the last years, proving a positive effect on respiratory system. Symptomatic therapies, including mechanical ventilation and cough assistance approaches, are important in NMD and respiratory muscle training may have benefit in strengthening respiratory muscles and should be offered patients with respiratory muscle weakness the same way as physiotherapy. Correct respiratory assessments and their correct interpretation are hallmarks for early diagnosis of hypoventilation syndrome and treatment.

Telemonitoring for Home Assisted Ventilation: A Narrative Review

The recent advent of remote ventilator telemonitoring has the potential to revolutionize home-assisted ventilation care in the United States and elsewhere. Home ventilation machines (i.e., respiratory assist devices and portable ventilators) can now wirelessly transmit usage and performance data to cloud-based web servers for remote access by participating clinicians. In this Focused Review, we provide an update on available technology, suggest practical applications for clinical care and research, and review supporting literature. Remote monitoring permits early data review, refinement of device settings to optimize ventilatory function, and troubleshooting if a new problem arises after initial setup. Data from home spirometry and noninvasively measured blood gas tensions can complement ventilator data to reflect physiological response. Acknowledging a paucity of published outcome studies, remote telemonitoring may be a cost-effective strategy to reduce emergency room visits, urgent clinic appointments, and hospitalizations. Ongoing clinical trials in Europe aim to expand on the benefit of this rapidly evolving technology. However, several barriers may hinder widespread implementation, especially in the United States. Clinicians must familiarize themselves with each ventilator manufacturer’s proprietary software to safely leverage this technology for improving care. Legal and ethical considerations threaten clinician interest. Medical insurance payers must adapt a reimbursement scheme to incentivize clinicians and durable medical equipment companies to perform this time-consuming service. Cohort-level ventilator data will facilitate multicenter clinical trials focused on improving the respiratory care of this vulnerable population.

Management of respiratory complications and rehabilitation in individuals with muscular dystrophies: 1st Consensus Conference report from UILDM - Italian Muscular Dystrophy Association (Milan, January 25-26, 2019)

Respiratory complications are common in the patient with muscular dystrophy. The periodic clinical and instrumental respiratory evaluation is extremely important. Despite the presence in the literature of updated guidelines, patient associations often report lack of knowledge of these pathologies, particularly in peripheral hospitals. The purpose of this work, inspired by the Italian Muscular Dystrophy Association (UILDM) is to improve management of respiratory problems necessary for the management of these patients complex. To this end, the main items that the specialist can meet in the follow-up of these pathologies have been analyzed and discussed, among which the respiratory basal evaluation, the criteria of adaptation to non-invasive ventilation, management of bronchial secretions, situations of respiratory emergency, indications for tracheostomy and the subject of advance directives of treatment (DAT).

Adult North Star Network (ANSN): Consensus Guideline For The Standard Of Care Of Adults With Duchenne Muscular Dystrophy

There are growing numbers of adults with Duchenne Muscular Dystrophy living well into their fourth decade. These patients have complex medical needs that to date have not been addressed in the International standards of care. We sought to create a consensus based standard of care through a series of multi-disciplinary workshops with specialists from a wide range of clinical areas: Neurology, Cardiology, Respiratory Medicine, Gastroenterology, Endocrinology, Palliative Care Medicine, Rehabilitation, Renal, Anaesthetics and Clinical Psychology. Detailed reports of evidence reviewed and the consensus building process were produced following each workshop and condensed into this final document which was approved by all members of the Adult North Star Network including service users. The aim of this document is to provide a framework to improve clinical services and multi-disciplinary care for adults living with Duchenne Muscular Dystrophy.

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.

Monitoring of noninvasive ventilation: comparative analysis of different strategies

Background

Noninvasive ventilation (NIV) represents an effective treatment for chronic respiratory failure. However, empirically determined NIV settings may not achieve optimal ventilatory support. Therefore, the efficacy of NIV should be systematically monitored. The minimal recommended monitoring strategy includes clinical assessment, arterial blood gases (ABG) and nocturnal transcutaneous pulsed oxygen saturation (SpO₂). Polysomnography is a theoretical gold standard but is not routinely available in many centers. Simple tools such as transcutaneous capnography (TcPCO₂) or ventilator built-in software provide reliable informations but their role in NIV monitoring has yet to be defined. The aim of our work was to compare the accuracy of different combinations of tests to assess NIV efficacy.

Methods

This retrospective comparative study evaluated the efficacy of NIV in consecutive patients through four strategies (A, B, C and D) using four different tools in various combinations. These tools included morning ABG, nocturnal SpO₂, TcPCO₂ and data provided by built-in software via a dedicated module. Strategy A (ABG + nocturnal SpO₂), B (nocturnal SpO₂ + TcPCO₂) and C (TcPCO₂ + builtin software) were compared to strategy D, which combined all four tools (NIV was appropriate if all four tools were normal).

Results

NIV was appropriate in only 29 of the 100 included patients. Strategy A considered 53 patients as appropriately ventilated. Strategy B considered 48 patients as appropriately ventilated. Strategy C misclassified only 6 patients with daytime hypercapnia.

Conclusion

Monitoring ABG and nocturnal SpO₂ is not enough to assess NIV efficacy. Combining data from ventilator built-in software and TcPCO₂ seems to represent the best strategy to detect poor NIV efficacy.

Trialregistration Institutional Review Board of the Société de Pneumologie de Langue Française (CEPRO 2016 Georges)

Disorders of sleep in spinal and bulbar muscular atrophy (Kennedy's disease)

INTRODUCTION

Spinal and bulbar muscular atrophy (SBMA) is a progressive, X-linked lower motor neuron disorder exclusively affecting men. Since knowledge on sleep disorders in SBMA is scarce compared to other motoneuron diseases, this retrospective case-control study aimed to investigate sleep and sleep-related breathing in patients with SBMA.

METHODS

In 23 non-ventilated patients with SBMA (median age 52 years), clinical disease characteristics, forced vital capacity and diagnostic polysomnographies were retrospectively evaluated. In 16 patients, overnight transcutaneous capnometry was available. Twenty-three male control subjects with chronic insomnia were matched for age and body mass index.

RESULTS

In patients with SBMA obstructive sleep apnoea (OSA, apnoea-hypopnoea index/AHI > 5/h) was more frequent than in control subjects (14/23 or 61% vs. 6/23 or 26%, p = 0.02), and median AHI was significantly higher in patients (9.0/h vs. 3.4/h, p < 0.01). Among SBMA patients, the AHI was not related to age or body mass index. Alveolar hypoventilation as reflected by nocturnal hypercapnia was found in 3/16 patients. Rapid eye movement (REM) sleep without atonia was present in 44% of SBMA patients but only in 4% of controls (p < 0.01). During REM and non-REM sleep, no behavioural abnormalities were observed in either group. Periodic limb movements in sleep (index > 15/h) were frequent in SBMA patients but rarely disrupted sleep.

CONCLUSIONS

In patients with SBMA, sleep-disordered breathing may comprise both OSA and nocturnal hypoventilation. REM sleep without atonia may also be found, but its clinical significance remains unclear. In patients complaining of sleep-related symptoms, cardiorespiratory polysomnography and transcutaneous capnometry are recommended.

Sleep disturbances in patients with amyotrophic lateral sclerosis: current perspectives

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease inevitably leading to generalized muscle weakness and premature death. Sleep disturbances are extremely common in patients with ALS and substantially add to the burden of disease for both patients and caregivers. Disruption of sleep can be caused by physical symptoms, such as muscle cramps, pain, reduced mobility, spasticity, mucus retention, and restless legs syndrome. In addition, depression and anxiety may lead to significant insomnia. In a small subset of patients, rapid eye movement (REM) sleep behavioral disorder may be present, reflecting neurodegeneration of central nervous system pathways which are involved in REM sleep regulation. With regard to overall prognosis, sleep-disordered breathing (SDB) and nocturnal hypoventilation (NH) are of utmost importance, particularly because NH precedes respiratory failure. Timely mechanical ventilation is one of the most significant therapeutic measures to prolong life span in ALS, and transcutaneous capnometry is superior to pulse oxymetry to detect NH early. In addition, it has been shown that in patients on home ventilatory support, survival time depends on whether normocapnia, normoxia, and elimination of apneic events during sleep can be reliably achieved. Several studies have investigated sleep patterns and clinical determinants of sleep disruption in ALS, but exact prevalence numbers are unknown. Thus, constant awareness for sleep-related symptoms is appropriate. Since no curative treatment can be offered to affected patients, sleep complaints should be thoroughly investigated in order to identify any treatable etiology and improve or stabilize quality of life as much as possible. The use of hypnotics should be confined to palliation during the terminal phase and refractory insomnia in earlier stages of the disease, taking into account that most compounds potentially aggravate SDB.

Non-invasive ventilation in amyotrophic lateral sclerosis

Non-invasive ventilation (NIV) has become an important cornerstone of symptomatic treatment in amyotrophic lateral sclerosis (ALS), improving survival and quality of life.

In this review, we summarize the most important recent developments and insights, including evidence of efficacy, indication criteria and time of initiation, ventilation parameters and adaptation strategies, treatment of complicating factors, transition from NIV to invasive ventilation, termination of NIV and end-of-life management. Recent publications have questioned former conventions and guideline recommendations, especially with regard to timing and prognostic factors; therefore, a fresh look and re-evaluation of current evidence is needed.

Sleep-related breathing disorders in facioscapulohumeral dystrophy

PURPOSE

Severe manifestations of facioscapulohumeral dystrophy (FSHD) may be associated with sleep-disordered breathing (SDB), including obstructive sleep apnea (OSA) and nocturnal hypoventilation (NH), but prevalence data are scarce. In patients with respiratory muscle weakness, detection of NH can be facilitated by transcutaneous capnometry, but respective data derived from FSHD patients have not yet been published.

METHODS

We collected sleep studies and capnometry recordings from 31 adult patients with genetically confirmed FSHD who were admitted to our sleep laboratory for first-ever evaluation of sleep-related breathing. Indications for admission included non-restorative sleep, morning headache, or excessive daytime sleepiness. In addition, sleep studies were initiated if symptoms or signs of respiratory muscle weakness were present. Thirty-one subjects with insomnia served as controls for comparison of respiratory measures during sleep.

RESULTS

In the FSHD group, 17/31 (55%) patients showed OSA and 8 (26%) had NH. NH would have been missed in 7/8 patients if only oximetry criteria of hypoventilation had been applied. Capnography results were correlated with disease severity as reflected by the Clinical Severity Score (CSS). Non-invasive ventilation (NIV) was started in 6 patients with NH and 3 individuals with OSA. Nocturnal continuous positive airway pressure was administered to 2 patients, and positional therapy was sufficient in 4 individuals. In patients initiated on NIV, nocturnal gas exchange already improved in the first night of treatment.

CONCLUSIONS

SDB is common in adult patients with FSHD complaining of sleep-related symptoms. It may comprise OSA, NH, and most often, the combination of both. Sleep-related hypercapnia is associated with disease severity. Transcutaneous capnometry is superior to pulse oximetry for detection of NH.

Beneficial effect of nocturnal oximetric control on the clinical and gasometric situation and the prognosis of patients with home non-invasive mechanical ventilation

INTRODUCTION AND OBJECTIVE

The effectiveness of home non-invasive mechanical ventilation (NIMV) is assessed by determining blood gas values in wakefulness, the evolution of their symptoms, and the monitoring of ventilation at night. The aim of our study is to evaluate whether defined values reached with outpatient monitoring by oximetry is related to the clinical, arterial gases and survival of a sample of patients with home NIMV.

MATERIAL AND METHOD

Retrospective observational cohort study of a series of patients receiving home NIMV treatment for different causes. Patients with amyotrophic lateral sclerosis and less than 3 months of follow-up were excluded. The evolution of the patient's symptoms, their baseline arterial blood gases in wakefulness, and home nocturnal oximetry records, are evaluated at each outpatient visit. Good maintained oximetry control (MOC) was defined when mean O2 saturation values were reached and maintained until the last revision. Patient groups were considered, according to whether or not a good MOC was achieved during follow-up.

RESULT

Four hundred patients were evaluated. Three hundred and sixty four (91%) were included in the study; their median age was 68 years, 51% were male. 37.6% had a good MOC during follow-up. Compared to patients with not good MOC, a better long-term mortality was obtained (16.8% vs 28.2%, P=.013), and an improvement in symptoms (33.8% vs 18.6%, P=.002) and a lower proportion of patients with persistently>50mmHg PaCO2 (14.2% vs. 33.9%, P<.001) was observed.

CONCLUSION

In the follow-up of patients with home NIMV in our context, values defined in home nocturnal oximetry (good MOC) are positively associated with clinical, gasometric and longer-term survival.

Respiratory involvement in neuromuscular disorders

PURPOSE OF REVIEW

In numerous neuromuscular disorders (NMDs), respiratory muscle weakness is present, and acute or chronic respiratory failure may evolve. Very often, respiratory involvement substantially adds to the burden of disease, impairs quality of life, or reduces life expectancy. This article summarizes new aspects of both diagnosis and management of respiratory muscle weakness in patients with NMDs.

RECENT FINDINGS

Drugs like deflazacort, ataluren, eteplirsen, and nusinersen are now approved treatments for Duchenne Muscular Dystrophy and Spinal Muscular Atrophy, and others are on their way in NMDs. Although observing how innovative drugs will change the natural history of these diseases, including respiratory function over time, adequate symptomatic treatment remains meaningful and is strongly recommended. Physicians should systematically take respiratory involvement into account to improve patients' quality of life and prognosis.

SUMMARY

First, it is outlined in which subtypes of NMD respiratory muscle dysfunction is particularly relevant. Second, new developments regarding diagnostic procedures, including respiratory muscle strength testing, spirometry, and sleep studies, are covered. Third, this article gives an overview on current concepts of ventilatory support and management of secretions in patients with NMD.

Prevalence of sleep apnoea and capnographic detection of nocturnal hypoventilation in amyotrophic lateral sclerosis

OBJECTIVE

This retrospective study aimed to investigate whether overnight oxymetry and early morning blood gas analysis predict nocturnal hypoventilation (NH) as reflected by night-time hypercapnia in patients with amyotrophic lateral sclerosis (ALS). In addition, prevalence and clinical determinants of sleep apnoea in ALS were evaluated.

METHODS

In 250 patients with non-ventilated ALS, transcutaneous capnometry was performed along with polysomnography or polygraphy and early morning blood gases.

RESULTS

123 patients were female, and 84 patients had bulbar-onset ALS. 40.0% showed NH, and an apnoea-hypopnoea index (AHI) >5/hour was found in 45.6%. In 22.3%, sleep apnoea and NH coincided. The obstructive apnoea index was significantly higher than the central apnoea index (p<0.0001). Both NH and sleep apnoea were significantly more common in male than in female patients. Sleep apnoea and AHI were associated with better bulbar function. Desaturation time (t_<90%) and transcutaneous CO₂ were negatively correlated with upright vital capacity. Early morning base excess (EMBE), bicarbonate and t_<90% were independent predictors of NH. However, among 100 patients with NH, 31 were missed by t_<90% >5 min and 17 were not identified when EMBE >3 mmol/L and t_<90% >5 min were combined.

CONCLUSION

In ALS, sleep apnoea is common and often accompanies NH. It is mainly obstructive, and central apnoea appears to be clinically irrelevant. Polygraphy or oxymetry alone are not sufficient to uncover NH. Combination of EMBE and t_<90% may increase sensitivity, but transcutaneous capnography is strongly recommended for reliable detection of NH in patients with ALS.

Detection of early nocturnal hypoventilation in neuromuscular disorders

Objective Nocturnal hypoventilation (NH) is a complication of respiratory involvement in neuromuscular disorders (NMD) that can evolve into symptomatic daytime hypercapnia if not treated proactively with non-invasive ventilation. This study aimed to assess whether NH can be detected in the absence of other signs of nocturnal altered gas exchange. Methods We performed nocturnal transcutaneous coupled (tc) pCO2/SpO2 monitoring in 46 consecutive cases of paediatric-onset NMD with a restrictive respiratory defect (forced vital capacity < 60%). Nocturnal hypoventilation was defined as tcPCO2 > 50 mmHg for > 25% of recorded time, and hypoxemia as tcSpO2 < 88% for > 5 minutes. Daytime symptoms and bicarbonate were recorded after overnight monitoring. Results Twenty-nine of 46 consecutive patients showed NH. Twenty-three patients did not have nocturnal hypoxemia and 18 were clinically asymptomatic. In 20 patients, PaCO2 in daytime blood samples was normal. Finally, 13/29 patients with NH had isolated nocturnal hypercapnia without nocturnal hypoxia, clinical NH symptoms, or daytime hypercapnia. Conclusions Paediatric patients with NMD can develop NH in the absence of clinical symptoms or significant nocturnal desaturation. Therefore, monitoring of NH should be included among nocturnal respiratory assessments of these patients as an additional tool to determine when to commence non-invasive ventilation.

[Update on the respiratory management of patients with chronic neuromuscular disease]

BACKGROUND

Neuromuscular diseases include a wide range of conditions that may involve potentially life-threatening respiratory complications (infection, respiratory failure).

SURVEILLANCE AND PULMONARY FUNCTION TESTS

For patients with neuromuscular diseases, clinical assessment of respiratory function and regular pulmonary function tests are needed to screen for nocturnal respiratory disorders, weakness of the diaphragm and potential restrictive disorders and/or chronic hypercapnic respiratory insufficiency, possibly with couch deficiency. MANAGEMENT OF NOCTURNAL RESPIRATORY DISORDERS AND CHRONIC RESPIRATORY FAILURE: Nocturnal respiratory assistance is an important phase of care for nocturnal respiratory disorders and chronic respiratory failure. This may involve continuous positive airway pressure, adaptative servo-ventilation or non-invasive ventilation with a facial or nasal mask. As needed, diurnal assistance may be proposed by mouthpiece ventilation. Should non-invasive ventilation prove insufficient, or if significant swallowing disorders or recurrent bronchial obstruction develop, or in case of prolonged intubation, tracheotomy may be required.

LOWER AIRWAY OBSTRUCTION

In case of lower airway infection with ineffective cough, physical therapy, associated with air stacking, intermittent positive pressure breathing or mechanical in-exsufflation may be proposed.

PATIENT-CENTERED MANAGEMENT

Care for swallowing disorders, nutritional counseling (cachexia, obesity), vaccinations and therapeutic education are integral elements of patient-centered management aiming to prevent the negative impact of infection and to manage respiratory failure of chronic neuromuscular disease.

Care management in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive and fatal neurodegenerative disease characterized by progressive weakness of voluntary muscles of movement as well as those for swallowing, speech and respiration. In the absence of curative treatment, care can improve quality of life, prolong survival, and support ALS patients and their families, and also help them to anticipate and prepare for the end of life. Multidisciplinary management in tertiary centers is recommended in close collaboration with general practitioners, home carers and a dedicated health network. Patients' follow-up deals mainly with motor impairment and physical disability, adaptation, nutrition and respiratory function. Involvement of palliative care as part of the multidisciplinary team management offers patients the possibility of discussing their end of life issues. This review summarizes the different aspects of ALS care, from delivering the diagnosis to the end of life, and the organization of its management.