Diaphragm pacing and noninvasive respiratory management of amyotrophic lateral sclerosis/motor neuron disease

Respiratory Management of Patients With Neuromuscular Weakness: An American College of Chest Physicians Clinical Practice Guideline and Expert Panel Report

BACKGROUND

Respiratory failure is a significant concern in neuromuscular diseases (NMDs). This CHEST guideline examines the literature on the respiratory management of patients with NMD to provide evidence-based recommendations.

STUDY DESIGN AND METHODS

An expert panel conducted a systematic review addressing the respiratory management of NMD and applied the Grading of Recommendations, Assessment, Development, and Evaluations approach for assessing the certainty of the evidence and formulating and grading recommendations. A modified Delphi technique was used to reach a consensus on the recommendations.

RESULTS

Based on 128 studies, the panel generated 15 graded recommendations, one good practice statement, and one consensus-based statement.

INTERPRETATION

Evidence of best practices for respiratory management in NMD is limited and is based primarily on observational data in amyotrophic lateral sclerosis. The panel found that pulmonary function testing every 6 months may be beneficial and may be used to initiate noninvasive ventilation (NIV) when clinically indicated. An individualized approach to NIV settings may benefit patients with chronic respiratory failure and sleep-disordered breathing related to NMD. When resources allow, polysomnography or overnight oximetry can help to guide the initiation of NIV. The panel provided guidelines for mouthpiece ventilation, transition to home mechanical ventilation, salivary secretion management, and airway clearance therapies. The guideline panel emphasizes that NMD pathologic characteristics represent a diverse group of disorders with differing rates of decline in lung function. The clinician's role is to add evaluation at the bedside to shared decision-making with patients and families, including respect for patient preferences and treatment goals, considerations of quality of life, and appropriate use of available resources in decision-making.

Noninvasive ventilatory support in morbid obesity

BACKGROUND

In the conventional management of the morbidly obese that normalizes the apnea-hypopnea index (AHI), CO2 levels often remain elevated.

METHODS

A retrospective review of morbidly obese patients using volume preset settings up to 1800ml to positive inspiratory pressures (PIPs) of 25-55cm H2O, or pressure control at 25-50cm H2O pressure via noninvasive interfaces up to continuously (CNVS).

RESULTS

Twenty-six patients, mean 55.6±14.8 years of age, weight 108-229kg, mean BMI 56.1 (35.5-77)kg/m², mean AHI 69.0±24.9, depended on up to CNVS for 3 weeks to up to 66 years. There were eleven extubations and seven decannulations to CNVS despite failure to pass spontaneous breathing trials. Thirteen were CNVS dependent for 92.2 patient-years with little to no ventilator free breathing ability (VFBA). Six used NVS from 10 to 23h a day, and others only for sleep. Fifteen patients with cough peak flows (CPF) less than 270L/m had access to mechanical insufflation-exsufflation (MIE) in the peri-extubation/decannulation period and long-term. The daytime end-tidal (Et)CO2 of 14 who were placed on sleep NVS without extubation or decannulation to it decreased from mean EtCO2 61.0±9.3-38.5±3.6mm Hg and AHI normalized to 2.2. Blood gas levels were normal while using NVS/CNVS. Pre-intubation PaCO2 levels, when measured, were as high as 183mm Hg before extubation to CNVS.

CONCLUSIONS

Ventilator unweanable morbidly obese patients can be safely extubated/decannulated and maintained indefinitely using up to CNVS rather than resort to tracheotomies.

Tracking a Fast-Moving Disease: Longitudinal Markers, Monitoring, and Clinical Trial Endpoints in ALS

Amyotrophic lateral sclerosis (ALS) encompasses a heterogeneous group of phenotypes with different progression rates, varying degree of extra-motor involvement and divergent progression patterns. The natural history of ALS is increasingly evaluated by large, multi-time point longitudinal studies, many of which now incorporate presymptomatic and post-mortem assessments. These studies not only have the potential to characterize patterns of anatomical propagation, molecular mechanisms of disease spread, but also to identify pragmatic monitoring markers. Sensitive markers of progressive neurodegenerative change are indispensable for clinical trials and individualized patient care. Biofluid markers, neuroimaging indices, electrophysiological markers, rating scales, questionnaires, and other disease-specific instruments have divergent sensitivity profiles. The discussion of candidate monitoring markers in ALS has a dual academic and clinical relevance, and is particularly timely given the increasing number of pharmacological trials. The objective of this paper is to provide a comprehensive and critical review of longitudinal studies in ALS, focusing on the sensitivity profile of established and emerging monitoring markers.

Long-Term Outcome of Amyotrophic Lateral Sclerosis in Korean Subjects

Objective

To report the latest long-term outcome of amyotrophic lateral sclerosis (ALS) and to analyze the predictors of prognosis.

Methods

Subjects who were diagnosed with ALS between January 2005 and December 2009 at a single institute were followed up until death or up to December 2014. Data regarding age, sex, date of onset, date of diagnosis, presence of bulbar symptoms on onset, date of initiation of non-invasive ventilation (NIV), and the date of tracheostomy were collected. Survival was assessed using Kaplan-Meier curves and multivariate analyses of the risk of death were performed using the Cox proportional hazards model.

Results

Among 212 suspicious subjects, definite ALS was diagnosed in 182 subjects. The survival rate at 3 and 5 years from onset was 61.5% and 40.1%, respectively, and the survival rate at 3 and 5 years post-diagnosis was 49.5% and 24.2%, respectively. Further, 134 patients (134/182, 73.6%) were initiated on NIV, and among them, 90 patients (90/182, 49.5%) underwent tracheostomy. Male gender and onset age of ≥65 years were independent predictors of adverse survival.

Conclusion

The analysis of long term survival in ALS showed excellent outcomes considering the overall poor prognosis of this disease.

Noninvasive Respiratory Management of Patients With Neuromuscular Disease

This review article describes definitive noninvasive respiratory management of respiratory muscle dysfunction to eliminate need to resort to tracheotomy. In 2010 clinicians from 22 centers in 18 countries reported 1,623 spinal muscular atrophy type 1 (SMA1), Duchenne muscular dystrophy (DMD), and amyotrophic lateral sclerosis users of noninvasive ventilatory support (NVS) of whom 760 required it continuously (CNVS). The CNVS sustained their lives by over 3,000 patient-years without resort to indwelling tracheostomy tubes. These centers have now extubated at least 74 consecutive ventilator unweanable patients with DMD, over 95% of CNVS-dependent patients with SMA1, and hundreds of others with advanced neuromuscular disorders (NMDs) without resort to tracheotomy. Two centers reported a 99% success rate at extubating 258 ventilator unweanable patients without resort to tracheotomy. Patients with myopathic or lower motor neuron disorders can be managed noninvasively by up to CNVS, indefinitely, despite having little or no measurable vital capacity, with the use of physical medicine respiratory muscle aids. Ventilator-dependent patients can be decannulated of their tracheostomy tubes.

Definition, discrimination, diagnosis and treatment of central breathing disturbances during sleep

The complexity of central breathing disturbances during sleep has become increasingly obvious. They present as central sleep apnoeas (CSAs) and hypopnoeas, periodic breathing with apnoeas, or irregular breathing in patients with cardiovascular, other internal or neurological disorders, and can emerge under positive airway pressure treatment or opioid use, or at high altitude. As yet, there is insufficient knowledge on the clinical features, pathophysiological background and consecutive algorithms for stepped-care treatment. Most recently, it has been discussed intensively if CSA in heart failure is a “marker” of disease severity or a “mediator” of disease progression, and if and which type of positive airway pressure therapy is indicated. In addition, disturbances of respiratory drive or the translation of central impulses may result in hypoventilation, associated with cerebral or neuromuscular diseases, or severe diseases of lung or thorax. These statements report the results of an European Respiratory Society Task Force addressing actual diagnostic and therapeutic standards. The statements are based on a systematic review of the literature and a systematic two-step decision process. Although the Task Force does not make recommendations, it describes its current practice of treatment of CSA in heart failure and hypoventilation.

Practical respiratory management in amyotrophic lateral sclerosis: evidence, controversies and recent advances

In amyotrophic lateral sclerosis, the onset of respiratory muscle weakness is silent, but survival following symptom recognition may only be a few weeks. Consequently, respiratory function and symptoms should be assessed every 2-3 months. Noninvasive ventilation improves symptoms, quality of life and survival, without increasing carer burden. Lung volume recruitment helps to reverse and prevent atelectasis, improving gas exchange, while techniques to enhance sputum clearance reduce the risk of mucus plugging and lower respiratory tract infections. When noninvasive support fails, often due to severe bulbar impairment, tracheostomy ventilation prolongs life. Most patients receiving tracheostomy ventilation at home report satisfactory quality of life, but at the expense of high carer burden. Diaphragmatic pacing is associated with an increased risk of death.

The evidence for symptomatic treatments in amyotrophic lateral sclerosis

PURPOSE OF REVIEW

Amyotrophic lateral sclerosis (ALS) is a progressive, incurable and fatal neurodegenerative disease. Few interventions significantly alter the disease course, but many symptomatic treatments exist to improve patients' quality of life. In this review, we describe our approach to symptomatic management of ALS and discuss the underlying evidence base.

RECENT FINDINGS

Discussion focuses predominantly on recently published articles. We cover management settings, disease-modifying treatment, vitamin D, respiratory management including noninvasive ventilation and diaphragmatic pacing, secretions, nutrition, dysphagia and gastrostomy, communication problems, mobility, spasticity, pain, cognition, depression and emotional lability, fatigue, sleep disturbance, head drop, prevention of deep venous thrombosis and end-of-life issues.

SUMMARY

Multidisciplinary specialist care appears to improve quality of life and survival. Riluzole remains the only available disease-modifying medication and confers a survival advantage of 2-3 months. Noninvasive ventilation improves quality of life and extends survival by approximately 7 months, at least in patients without severe bulbar problems. Nutrition is an independent prognostic factor; whether gastrostomy improves survival and quality of life remains unclear and further studies are underway. Many other symptomatic treatments appear helpful to individuals in clinic, but further randomized clinical trials are required to provide a more robust evidence base.

Comprehensive rehabilitative care across the spectrum of amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease) is a neurodegenerative disease that results in progressive muscle weakness and wasting. There is no known cure and the disease is uniformly fatal.

PURPOSE

This review discusses current concepts in ALS care, from breaking the diagnosis to end-of-life care. People with ALS have several multidisciplinary needs due to a complex and dynamic disease process. They benefit from rehabilitation interventions that are individualized and have the goal of optimizing independence, function, and safety. These strategies also help minimize symptomatic burden and maximize quality of life.

CONCLUSION

Patient-centered, multidisciplinary care has a significant impact on the life of people with ALS and is the current standard of care for this patient population.

A plural role for lipids in motor neuron diseases: energy, signaling and structure

Motor neuron diseases (MNDs) are characterized by selective death of motor neurons and include mainly adult-onset amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). Neurodegeneration is not the single pathogenic event occurring during disease progression. There are multiple lines of evidence for the existence of defects in lipid metabolism at peripheral level. For instance, hypermetabolism is well characterized in ALS, and dyslipidemia correlates with better prognosis in patients. Lipid metabolism plays also a role in other MNDs. In SMA, misuse of lipids as energetic nutrients is described in patients and in related animal models. The composition of structural lipids in the central nervous system is modified, with repercussion on membrane fluidity and on cell signaling mediated by bioactive lipids. Here, we review the main epidemiologic and mechanistic findings that link alterations of lipid metabolism and motor neuron degeneration, and we discuss the rationale of targeting these modifications for therapeutic management of MNDs.

Acute and chronic respiratory failure

Respiratory failure (RF) can be attributed to a plethora of neuromuscular diseases (NMDs) and manifests clinically in a multitude of overt or more subtle ways. The basic principles of pathophysiology, diagnosis and treatment of neurologic diseases and of RF apply concomitantly to this subset of patients. Various entities should be approached according to the latest evidence-based recommendations. Treatment follows the natural disease progression, from minimal respiratory assistance to mechanical ventilation (MV). A comprehensive treatment plan has to be formulated that takes into consideration the patient's wishes.

Multidisciplinary clinics: optimizing treatment for patients with amyotrophic lateral sclerosis

SUMMARY Amyotrophic lateral sclerosis is an incurable, lethal neurodegenerative disease. The majority of patients die from respiratory failure within 2–5 years after symptom onset. Recent studies show a paradigm shift in the method of delivering a number of effective treatments through an emerging network of multidisciplinary clinics. This article focuses on the role played by these clinics in raising the standard-of-care for patients with amyotrophic lateral sclerosis. Although newly developed treatments are still underutilized, substantial progress is being made by multidisciplinary clinics, which play a pivotal role in coordinating access to effective therapeutics.