Using transcutaneous carbon dioxide monitor (TOSCA 500) to detect respiratory failure in patients with amyotrophic lateral sclerosis: A validation study

Evaluation and management of dyspnea as the dominant presenting feature in neuromuscular disorders

Dyspnea is a common symptom in neuromuscular disorders and, although multifactorial, it is usually due to respiratory muscle involvement, associated musculoskeletal changes such as scoliosis or, in certain neuromuscular conditions, cardiomyopathy. Clinical history can elicit symptoms such as orthopnea, trepopnea, sleep disruption, dysphagia, weak cough, and difficulty with secretion clearance. The examination is essential to assist with the diagnosis of an underlying neurologic disorder and determine whether dyspnea is from a cardiac or pulmonary origin. Specific attention should be given to possible muscle loss, use of accessory muscles of breathing, difficulty with neck flexion/extension, presence of thoraco-abdominal paradox, conversational dyspnea, cardiac examination, and should include a detailed neurological examination directed at the suspected differential diagnosis. Pulmonary function testing including sitting and supine spirometry, measures of inspiratory and expiratory muscle strength, cough peak flow, sniff nasal inspiratory pressure, pulse oximetry, transcutaneous CO2, and arterial blood gases will help determine the extent of the respiratory muscle involvement, assess for hypercapnic or hypoxemic respiratory failure, and qualify the patient for noninvasive ventilation when appropriate. Additional testing includes dynamic imaging with sniff fluoroscopy or diaphragm ultrasound, and diaphragm electromyography. Polysomnography is indicated for sleep related symptoms that are not otherwise explained. Noninvasive ventilation alleviates dyspnea and nocturnal symptoms, improves quality of life, and prolongs survival. Therapy targeted at neuromuscular disorders may help control the disease or favorably modify its course. For patients who have difficulty with secretion clearance, support of expiratory function with mechanical insufflation-exsufflation, oscillatory devices can reduce the aspiration risk.

Expanded central role of the respiratory physiotherapists in the community setting

The development of community hubs through the Slaintecare initiative will rely on respiratory physiotherapists and clinical nurse specialists for the management of chronic respiratory diseases. The role of the respiratory physiotherapist has evolved dramatically over the last decade. We review the increasing scope of practice of the physiotherapist and the evidence base for same. We pay particular attention to the role of the physiotherapist in areas such as pulmonary rehabilitation, sputum clearance, neuromuscular disease, chronic respiratory failure, ambulatory oxygen assessments and dysfunctional breathing. We give an in depth review of sputum clearance techniques. We also address areas of potential future expansion for the role of the physiotherapist such as prescription and initiation of non-invasive ventilation.

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.

Transcutaneous CO2 monitoring as indication for inpatient non-invasive ventilation initiation in patients with amyotrophic lateral sclerosis

INTRODUCTION/AIMS

Amyotrophic lateral sclerosis (ALS) is characterized by profound muscle weakness, including diaphragmatic weakness resulting in hypercapnic respiratory failure. While non-invasive ventilation (NIV) is usually initiated in the home, patients presenting with hypercapnic respiratory failure may be at high risk of adverse outcomes with delays in treatment. We aim to describe the clinical utility of transcutaneous CO₂ (TCO₂ ) to assess the need for inpatient initiation of NIV.

METHODS

Eight patients from the University of Michigan Pranger ALS clinic were directly admitted to the hospital for urgent initiation of NIV between May 2020-May 2021. A retrospective review of electronic medical records, including pre-hospital pulmonary function assessments, hospitalization blood gases, and NIV use metrics was performed.

RESULTS

All eight patients had symptoms of respiratory insufficiency at time of admission, although not all patients had forced vital capacity (FVC) measurements that would identify need for NIV. All patients had measured TCO₂  > 45 mmHg. Seven of eight patients had worsening hypercapnia after admission, indicating advanced respiratory failure. All patients were titrated to tolerance of continuous nocturnal NIV while in the hospital, with an average length of stay of 6.5 days (range, 3-8). All patients demonstrated compliance with NIV, >4 h, at post-hospital follow-up.

DISCUSSION

Many current ambulatory measurements underestimate, or incompletely evaluate, respiratory dysfunction, and arterial blood gases are not typically readily available. Outpatient TCO₂ measurements can serve as a useful screening tool to identify ALS patients who would benefit from inpatient initiation and titration of NIV.

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.

Respiratory muscle testing in amyotrophic lateral sclerosis: a practical approach

In amyotrophic lateral sclerosis (ALS), respiratory muscle weakness leads to respiratory failure and death. Non-invasive positive pressure ventilation (NIPPV) appears to reduce lung function decline, thus improving survival and quality-of-life of patients affected by the disease. Unfortunately, clinical features and timing to start NIPPV are not well defined. Starting from recent findings, we examine established and novel tests of respiratory muscle function that could help clinicians decide whether and when to start NIPPV in ALS. Non-invasive tests estimate the function of inspiratory, expiratory, and bulbar muscles, whereas clinical examination allows to assess the overall neurologic and respiratory symptoms and general conditions. Most of the studies recommend that together with a thorough clinical evaluation of the patient according to current guidelines, vital capacity, maximal static and sniff nasal inspiratory pressures, maximal static expiratory pressures and peak cough expiratory flow, and nocturnal pulse oximetry be measured. A sound understanding of physiology can guide the physician also through the current armamentarium for additional supportive treatments for ALS, such as symptomatic drugs and new treatments to manage sialorrhea and thickened saliva, cough assistance, air stacking, and physiotherapy. In conclusion, careful clinical and functional evaluation of respiratory function and patient's preference are key determinants to decide "when" and "to whom" respiratory treatments can be provided.

Assessment of pulmonary function in amyotrophic lateral sclerosis: when can polygraphy help evaluate the need for non-invasive ventilation?

BACKGROUND

Non-invasive positive-pressure ventilation (NPPV) is an established, effective, long-term treatment for patients with amyotrophic lateral sclerosis (ALS), but the correct indicators for the establishment of NPPV have not been defined.

METHODS

In this retrospective study, records (spirometry, nocturnal polygraphy, nocturnal blood gases) of 131 patients with ALS were reviewed in order to evaluate the role of polygraphy for prediction of respiratory failure in ALS.

RESULTS

The patient group reporting with versus without dyspnoea had significantly lower values on the revised ALS-Functional Rating Scale (ALSFRS-R), vital capacity (VC), forced VC (FVC), arterial oxygen saturation and arterial oxygen tension readings, including a higher apnoea-hypopnoea index. 23 patients, who did not report about dyspnoea, had an FVC of <75%. Nocturnal hypoventilation was observed in 67% of the patients with ALS independent of their ALSFRS-R. The patient group with nocturnal hypoventilation was characterised by a significantly lower VC, FVC and maximal static inspiratory pressure compared with the group without nocturnal hypoventilation. However, also in the absence of nocturnal hypoventilation, 8 patients had a VC <50% as predicted.

DISCUSSION

Our study shows that in patients not reporting dyspnoea and having an FVC of >75%, nocturnal hypoventilation was observed in nearly every second patient. Therefore, for the question of whether NPPV should be initiated, polygraphy does not provide useful additional information if the FVC is already <75% as predicted. However, in patients with more or less normal lung function parameters or where lung spirometry cannot perform adequately (eg, bulbar ALS), it can provide sufficient evidence for the need of NPPV.

Supportive and symptomatic management of amyotrophic lateral sclerosis

The main aims in the care of individuals with amyotrophic lateral sclerosis (ALS) are to minimize morbidity and maximize quality of life. Although no cure exists for ALS, supportive and symptomatic care provided by a specialist multidisciplinary team can improve survival. The basis for supportive management is shifting from expert consensus guidelines towards an evidence-based approach, which encourages the use of effective treatments and could reduce the risk of harm caused by ineffective or unsafe interventions. For example, respiratory support using noninvasive ventilation has been demonstrated to improve survival and quality of life, whereas evidence supporting other respiratory interventions is insufficient. Increasing evidence implicates a causal role for metabolic dysfunction in ALS, suggesting that optimizing nutrition could improve quality of life and survival. The high incidence of cognitive dysfunction and its impact on prognosis is increasingly recognized, although evidence for effective treatments is lacking. A variety of strategies are used to manage the other physical and psychological symptoms, the majority of which have yet to be thoroughly evaluated. The need for specialist palliative care throughout the disease is increasingly recognized. This Review describes the current approaches to symptomatic and supportive care in ALS and outlines the current guidance and evidence for these strategies.

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.

Treatment of respiratory impairment in patients with motor neuron disease in the Netherlands: patient preference and timing of referral

BACKGROUND AND PURPOSE

We assessed the first evaluation at a large ventilation clinic in the Netherlands to: (i) determine what proportion of patients with motor neuron disease would benefit from earlier referral; and (ii) examine the patient preferences regarding ventilatory support.

METHODS

Observational study at a single centre with a catchment area of 7.6 million inhabitants. Data on disease status, the referral process and patients' preferences regarding ventilatory support were collected during the first home ventilation services (HVS) assessment and analysed for correlation with the presence of daytime hypercapnia and suspected nocturnal hypoventilation. The latter conditions require immediate (within 48 h) or subacute (within 3 weeks) initiation of ventilatory support.

RESULTS

Vital capacity (in percentage of predicted value, VC%pred) was assessed by referring physicians in 84% of the 217 referred patients; the mean VC%pred was 69% (SD 16). One-hundred and ninety-one patients attended the first HVS assessment without ventilatory support, at a median of 21 days following referral: 18% had respiratory failure (daytime hypercapnia), 19% had normocapnia but were suspected of nocturnal hypoventilation, and 63% had normocapnia without symptoms. Following the HVS assessment, 25 patients (13%) declined home mechanical ventilation; this occurred more often in patients with (14/70) compared with patients without respiratory impairment (11/121; P < 0.05).

CONCLUSION

A meaningful proportion of patients who desire ventilatory support are referred to a ventilation clinic after already developing respiratory failure. Future studies could examine means, including more sensitive respiratory measures, to detect those patients who could benefit from earlier referral.