Noninvasive respiratory assistance as aid for respiratory care in neuromuscular disorders.

Chronic respiratory failure is a common complication of neuromuscular disease. The use of noninvasive ventilation and mechanically assisted cough can reduce symptoms of hypoventilation, slow lung function decline, improve sleep quality, and in some cases prolong survival in patients with neuromuscular disease. In this article, we review indications for the initiation of noninvasive ventilation and mechanically assisted cough as well as provide recommendations for settings and titration. We discuss the evidence supporting the use of noninvasive ventilation as an adjunct to rehabilitation in patients with neuromuscular disease. Lastly, we review the ethical considerations that are relevant to decisions regarding initiation and cessation of noninvasive ventilation. While noninvasive ventilation and mechanically assisted cough have become standards of care in many forms of neuromuscular disease, most current recommendations are based on expert opinion rather than much-needed data from prospective clinical trials and we emphasize topics requiring future research.

Chronic Neuromuscular Respiratory Failure and Home Assisted Ventilation.

Chronic respiratory failure is a common, important complication of many types of neuromuscular and chest wall disorders. While the pathophysiology of each disease may be different, these disorders can variably affect all muscles involved in breathing, including inspiratory, expiratory, and bulbar muscles, ultimately leading to chronic respiratory failure and hypoventilation. The use of home assisted ventilation through noninvasive interfaces aims to improve the symptoms of hypoventilation, improve sleep quality, and, when possible, improve mortality. An increasing variety of interfaces has allowed for improved comfort and compliance. In a minority of scenarios, noninvasive ventilation is either not appropriate or no longer effective due to disease progression, and a transition to tracheal ventilation should be considered.

Successful Treatment of Prolonged, Severe Coronavirus Disease 2019 Lower Respiratory Tract Disease in a B cell Acute Lymphoblastic Leukemia Patient With an Extended Course of Remdesivir and Nirmatrelvir/Ritonavir.

A patient with B-cell acute lymphoblastic leukemia (ALL) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had persistent, progressive pneumonia with viremia after 5 months of infection despite monoclonal antibodies, intravenous (IV) remdesivir and prolonged oral steroids. Twenty days of nirmatrelvir/ritonavir and 10 days of IV remdesivir led to full recovery.

Extreme Sawtooth-Sign in Motor Neuron Disease (MND) suggests Laryngeal Resistance to Forced Expiratory Airflow.

OBJECTIVE: The impact of laryngeal dysfunction on airflow has not been well characterized in motor neuron disease (MND). This study aimed to detect and characterize extreme airflow oscillations informally observed during volitional cough and forced vital capacity (FVC) tasks in individuals with MND who demonstrated neurolaryngeal impairments including reduced speed and extent of vocal fold abduction compared to healthy controls during volitional cough expulsion. The extreme airflow oscillations in the MND group, when viewed as a flow-volume loop, appeared similar to the "sawtooth-sign." If the airflow oscillations are periodic in a range similar to phonation, they may reflect reduced laryngeal patency. METHODS: Volitional cough and FVC airflow data (3 trials each) from 12 participants with MND with bulbar/laryngeal involvement (3 F; ages 45-76) and 12 healthy controls (6 F; ages 41-68) were analyzed for periodicity. Percent and absolute durations of periodicity of the flow oscillations were calculated by an algorithm applied to the airflow signals. In addition, the frequency, magnitude, and kurtosis of the periodic airflow oscillations were described and compared between groups. RESULTS: In both volitional cough and FVC trials, the percent of airflow periodicity during forced expiration was significantly higher (z = 3.54) in individuals with MND, adjusted for age and sex. Periodic airflow accounted for on average 28% of the total time in participants with MND and was within a frequency range similar to phonation. Magnitude of the airflow oscillations was also larger for participants with MND (z = 3.46), and kurtosis of airflow was smaller (z = -4.70) during forced expiration, indicating persistent airflow oscillations throughout exhalation. CONCLUSIONS: The significantly larger-magnitude, lower-kurtosis, and more prominent presence of sawtooth-like airflow periodicity within a frequency range similar to phonation observed in individuals with MND with neurolaryngeal impairments suggests glottic airflow resistance during forced expiration.

Building a home ventilation programme: population, equipment, delivery and cost.

Home mechanical ventilation (HMV) improves quality of life and survival in patients with neuromuscular disorders (NMD). Developing countries may benefit from published evidence regarding the prevalence, cost of equipment, technical issues and organisation of HMV in NMD, facilitating the development of local turn-key HMV programmes. Unfortunately, such evidence is scattered in the existing literature. We searched Medline for publications in English and French from 2005 to 2020. This narrative review analyses 24 international programmes of HMV. The estimated prevalence (min-max) of HMV is ±7.3/100 000 population (1.2-47), all disorders combined. The prevalence of HMV is associated with the gross domestic product per capita in these 24 countries. The prevalence of NMD is about 30/100 000 population, of which ±10% would use HMV. Nocturnal (8/24 hour), discontinuous (8-16/24 hours) and continuous (>16/24 hours) ventilation is likely to concern about 60%, 20% and 20% of NMD patients using HMV. A minimal budget of about 168€/patient/year (504€/100 000 population), including the cost of equipment solely, should address the cost of HMV equipment in low-income countries. When services and maintenance are included, the budget can drastically increase up to between 3232 and 5760€/patient/year. Emerging programmes of HMV in developing countries reveal the positive impact of international cooperation. Today, at least 12 new middle, and low-income countries are developing HMV programmes. This review with updated data on prevalence, technical issues, cost of equipment and services for HMV should trigger objective dialogues between the stakeholders (patient associations, healthcare professionals and politicians); potentially leading to the production of workable strategies for the development of HMV in patients with NMD living in developing countries.

Optimal NIV Medicare Access Promotion: Patients With Thoracic Restrictive Disorders: 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 noninvasive ventilation (NIV) do not recognize the benefits of early initiation of NIV for those with thoracic restrictive disorders and do not address the unique needs for daytime support as the patients progress to ventilator dependence. This document summarizes the work of the thoracic restrictive disorder Technical Expert Panel working group. The most pressing current coverage barriers identified were: (1) delays in implementing NIV treatment; (2) lack of coverage for many nonprogressive neuromuscular diseases; and (3) lack of clear policy indications for home mechanical ventilation (HMV) support in thoracic restrictive disorders. To best address these issues, we make the following key recommendations: (1) given the need to encourage early initiation of NIV with bilevel positive airway pressure devices, we recommend that symptoms be considered as a reason to initiate therapy even at mildly reduced FVCs; (2) broaden CO2 measurements to include surrogates such as transcutaneous, end-tidal, or venous blood gas; (3) expand the diagnostic category to include phrenic nerve injuries and disorders of central drive; (4) allow a bilevel positive airway pressure device to be advanced to an HMV when the vital capacity is < 30% or to address severe daytime respiratory symptoms; and (5) provide additional HMV when the patient is ventilator dependent with use > 18 h per day. Adoption of these proposed recommendations would result in the right device, at the right time, for the right type of patients with thoracic restrictive disorders.

Mouthpiece ventilation in neuromuscular disorders: Narrative review of technical issues important for clinical success.

In neuromuscular disorders (NMDs), nocturnal non-invasive ventilation (NIV) via a nasal mask is offered when hypercapnic respiratory failure occurs. With disease progression, nocturnal NIV needs to be extended into the daytime. Mouthpiece ventilation (MPV) is an option for daytime NIV. MPV represents a difficult task for home ventilators due to rapidly changing load conditions resulting from intermittent connections and disconnections from MPV circuit. The 252nd ENMC International Expert Workshop, held March 6th to 8th 2020 in Amsterdam, reported general guidelines for management of daytime MPV in NMDs. This report could not present all the detail regarding the technical issues important for clinical success of MPV. Based on the expert workshop discussions and the evidence from existing studies, the current narrative review aims to identify the technical issues of MPV and offers guidance via a decisional algorithm and educational figures providing relevant information that is important for successful implementation of MPV.

Effects of Mouthpiece Noninvasive Ventilation on Speech in Men With Muscular Dystrophy: A Pilot Study.

Purpose The use of noninvasive ventilation (NIV) is on the rise as an alternative to tracheostomy for individuals with neuromuscular disorders with life-prolonging and quality-of-life benefits. This pilot study was designed to determine if mouthpiece NIV (M-NIV) alters speech in individuals with muscular dystrophy (MD). Method Eight men (23-44 years), seven with Duchenne MD and one with Becker MD, who used daytime M-NIV, were asked to sustain phonation, count, and read under three conditions: (a) Uncued (no instructions), (b) With M-NIV (cued to use M-NIV with all speaking breaths), and (c) Without M-NIV (as tolerated). Breath group and inspiratory durations, syllables/breath group, and relative sound pressure level were determined from audio and video recordings. Results Uncued condition: Participants used the ventilator for all inspirations that preceded sustained phonation and counting. During reading, four participants used M-NIV for all inspirations, one never used it, and three used it for some (19%-41%) inspirations. With- versus Without-M-NIV conditions: Breath group duration was significantly longer across all tasks, syllables per breath group were significantly greater during reading, and inspiratory pause duration during reading was significantly longer with M-NIV than without. Sound pressure level was significantly higher during the first second of sustained phonation with M-NIV (though not for counting and reading). Two participants were unable to complete the reading task audibly without using their M-NIV. Conclusions Speech may be better with M-NIV than without because it is possible to produce longer breath groups and some people with severe respiratory muscle weakness may not be able to speak at all without ventilator-supplied air. Nevertheless, the longer inspiratory pauses that accompany M-NIV may interrupt the flow of speech. Future research is needed to determine the most effective way to use M-NIV for speaking and whether training participants in its use can bring even greater speech benefits.

The US Strategic National Stockpile Ventilators in Coronavirus Disease 2019: A Comparison of Functionality and Analysis Regarding the Emergency Purchase of 200,000 Devices.

BACKGROUND: Early in the coronavirus disease 2019 (COVID-19) pandemic, there was serious concern that the United States would encounter a shortfall of mechanical ventilators. In response, the US government, using the Defense Production Act, ordered the development of 200,000 ventilators from 11 different manufacturers. These ventilators have different capabilities, and whether all are able to support COVID-19 patients is not evident. RESEARCH QUESTION: Evaluate ventilator requirements for affected COVID-19 patients, assess the clinical performance of current US Strategic National Stockpile (SNS) ventilators employed during the pandemic, and finally, compare ordered ventilators' functionality based on COVID-19 patient needs. STUDY DESIGN AND METHODS: Current published literature, publicly available documents, and lay press articles were reviewed by a diverse team of disaster experts. Data were assembled into tabular format, which formed the basis for analysis and future recommendations. RESULTS: COVID-19 patients often develop severe hypoxemic acute respiratory failure and adult respiratory defense syndrome (ARDS), requiring high levels of ventilator support. Current SNS ventilators were unable to fully support all COVID-19 patients, and only approximately half of newly ordered ventilators have the capacity to support the most severely affected patients; ventilators with less capacity for providing high-level support are still of significant value in caring for many patients. INTERPRETATION: Current SNS ventilators and those on order are capable of supporting most but not all COVID-19 patients. Technologic, logistic, and educational challenges encountered from current SNS ventilators are summarized, with potential next-generation SNS ventilator updates offered.

Lifetime Care of Duchenne Muscular Dystrophy.

Individuals with Duchenne muscular dystrophy (DMD) have evolving sleep and respiratory pathophysiology over their lifetimes. Across the lifespan of DMD, various sleep-related breathing disorders (SRBD) have been described, including obstructive sleep apnea, central sleep apnea, and nocturnal hypoventilation. In addition to SRBD, individuals with DMD can be affected by insomnia, chronic pain and other factors interfering with sleep quality, and daytime somnolence. The natural progression of DMD pathophysiology has changed with the introduction of therapies for downstream pathologic pathways and will continue to evolve with the development of therapies that target function and expression of dystrophin.

Swallowing with Noninvasive Positive-Pressure Ventilation (NPPV) in Individuals with Muscular Dystrophy: A Qualitative Analysis.

The purpose of the study is to describe experiences of swallowing with two forms of noninvasive positive-pressure ventilation (NPPV): mouthpiece NPPV (M-NPPV) and nasal bilevel positive airway pressure (BPAP) in people with muscular dystrophy. Ten men (ages 22-42 years; M = 29.3; SD = 7.1) with muscular dystrophy (9 with Duchenne's; 1 with Becker's) completed the Eating Assessment Tool (EAT-10; Ann Otol Rhinol Laryngol 117(12):919-924 [33]) and took part in semi-structured interviews. The interviews were audio recorded, transcribed, and verified. Phenomenological qualitative research methods were used to code (Dedoose.com) and develop themes. All participants affirmed dysphagia symptoms via responses on the EAT-10 (M = 11.3; SD = 6.38; Range = 3-22) and reported eating and drinking with M-NPPV and, to a lesser extent, nasal BPAP. Analysis of interview data revealed three primary themes: (1) M-NPPV improves the eating/drinking experience: Most indicated that using M-NPPV reduced swallowing-related dyspnea. (2) NPPV affects breathing-swallowing coordination: Participants described challenges and compensations in coordinating swallowing with ventilator-delivered inspirations, and that the time needed to chew solid foods between ventilator breaths may lead to dyspnea and fatigue. (3) M-NPPV aids cough effectiveness: Participants described improved cough strength following large M-NPPV delivered inspirations (with or without breath stacking). Although breathing-swallowing coordination is challenging with NPPV, participants reported that eating and drinking is more comfortable than when not using it. Overall, eating and drinking with NPPV delivered via a mouthpiece is preferred and is likely safer for swallowing than with nasal BPAP. M-NPPV (but not nasal BPAP) is reported to improve cough effectiveness, an important pulmonary defense in this population.

Experiences of Speaking With Noninvasive Positive Pressure Ventilation: A Qualitative Investigation.

Purpose The aim of this study was to describe experiences of speaking with 2 forms of noninvasive positive pressure ventilation (NPPV)-mouthpiece NPPV (M-NPPV) and nasal bilevel positive airway pressure (BPAP)-in people with neuromuscular disorders who depend on NPPV for survival. Method Twelve participants (ages 22-68 years; 10 men, 2 women) with neuromuscular disorders (9 Duchenne muscular dystrophy, 1 Becker muscular dystrophy, 1 postpolio syndrome, and 1 spinal cord injury) took part in semistructured interviews about their speech. All subjects used M-NPPV during the day, and all but 1 used BPAP at night for their ventilation needs. Interviews were audio-recorded, transcribed, and verified. A qualitative descriptive phenomenological approach was used to code and develop themes. Results Three major themes emerged from the interview data: (a) M-NPPV aids speaking (by increasing loudness, utterance duration, clarity, and speaking endurance), (b) M-NPPV interferes with the flow of speaking (due to the need to pause to take a breath, problems with mouthpiece placement, and difficulty in using speech recognition software), and (c) nasal BPAP interferes with speaking (by causing abnormal nasal resonance, muffled speech, mask discomfort, and difficulty in coordinating speaking with ventilator-delivered inspirations). Conclusion These qualitative data from chronic NPPV users suggest that both M-NPPV and nasal BPAP may interfere with speaking but that speech is usually better and speaking is usually easier with M-NPPV. These findings can be explained primarily by the nature of the 2 ventilator delivery systems and their interfaces.

Respiratory Care of Patients With Neuromuscular Disease.

Neuromuscular diseases are a heterogeneous group of neurologic diseases that affect a number of neural structures including the motor nerves, neuromuscular junctions, or the muscles themselves. Although many of the diseases are rare, the total number of individuals who present to a pulmonologist or respiratory care provider is significant. Approaches to care include regular and careful clinical follow-up of symptoms of sleep-disordered breathing, daytime hypoventilation, as well as cough and swallowing effectiveness. Noninvasive support with nocturnal mask ventilation and a pressure support device can be extraordinarily helpful and delay daytime ventilatory failure. When daytime ventilatory failure develops, other noninvasive methods are available for portable assistance. Support of cough function with manual assistance, a resuscitator bag, and/or mechanical insufflation-exsufflation can help prevent and treat infection. Referral for swallowing evaluation and treatment is very important for those with impaired bulbar function. This comprehensive respiratory care approach to individuals with neuromuscular disease and respiratory system involvement is essential to maintaining the health and longevity of these individuals.

Respiratory Management of the Patient With Duchenne Muscular Dystrophy.

In 2010, Care Considerations for Duchenne Muscular Dystrophy, sponsored by the Centers for Disease Control and Prevention, was published in Lancet Neurology, and in 2018, these guidelines were updated. Since the publication of the first set of guidelines, survival of individuals with Duchenne muscular dystrophy has increased. With contemporary medical management, survival often extends into the fourth decade of life and beyond. Effective transition of respiratory care from pediatric to adult medicine is vital to optimize patient safety, prognosis, and quality of life. With genetic and other emerging drug therapies in development, standardization of care is necessary to accurately assess treatment effects in clinical trials. This revision of respiratory recommendations preserves a fundamental strength of the original guidelines: namely, reliance on a limited number of respiratory tests to guide patient assessment and management. A progressive therapeutic strategy is presented that includes lung volume recruitment, assisted coughing, and assisted ventilation (initially nocturnally, with the subsequent addition of daytime ventilation for progressive respiratory failure). This revision also stresses the need for serial monitoring of respiratory muscle strength to characterize an individual's respiratory phenotype of severity as well as provide baseline assessments for clinical trials. Clinical controversies and emerging areas are included.

Pathophysiology of Neuromuscular Respiratory Diseases.

Gas exchange between the atmosphere and the human body depends on the lungs and the function of the respiratory pump. The respiratory pump consists of the respiratory control center located in the brain, bony rib cage, diaphragm, and intercostal, accessory, and abdominal muscles. A variety of muscles serve to fine-tune adjustments of ventilation to metabolic demands. Appropriate evaluation and interventions can prevent respiratory complications and prolong life in individuals with neuromuscular diseases. This article discusses normal function of the respiratory pump, general pathophysiologic issues, and abnormalities in more common neuromuscular diseases.

Utility of Pulse Oximetry to Detect Aspiration: An Evidence-Based Systematic Review.

Pulse oximetry is a commonly used means to measure peripheral capillary oxyhemoglobin saturation (SpO2). Potential use of pulse oximetry to detect aspiration is attractive to clinicians, as it is readily available, quick, and noninvasive. However, research regarding validity has been mixed. This systematic review examining evidence on the use of pulse oximetry to detect a decrease in SpO2 indicating aspiration during swallowing is undertaken to further inform clinical practice in dysphagia assessment. A multi-engine electronic search was conducted on 8/25/16 and updated on 4/8/17 in accordance with standards published by the Preferred Reporting for Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA). Inclusion criteria included use of pulse oximetry to detect aspiration with simultaneous confirmation of aspiration via a gold standard instrumental study. Keywords included dysphagia or aspiration AND pulse oximetry. Articles meeting criteria were reviewed by two blinded co-investigators. The search yielded 294 articles, from which 19 were judged pertinent and reviewed in full. Ten met the inclusion criteria and all were rated at Level III-2 on the Australian Diagnostic Levels of Evidence. Study findings were mixed with sensitivity ranging from 10 to 87%. Potentially confounding variables were observed in all studies reviewed, and commonly involved defining "desaturation" within a standard measurement error range (~ 2%), mixed populations, mixed viscosities/textures observed during swallowing, and lack of comparison group. The majority of studies failed to demonstrate an association between observed aspiration and oxygen desaturation. Current evidence does not support the use of pulse oximetry to detect aspiration.