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

Unraveling sleep respiratory dysfunction in amyotrophic lateral sclerosis: Beyond the apnea-hypopnea index and sleep-related hypoxia

The timely introduction of non-invasive ventilation (NIV) is extremely relevant in the multidisciplinary management of patients affected by amyotrophic lateral sclerosis (ALS) and is based on the proper identification of red flags for early diaphragmatic exhaustion. Polygraphic sleep recording may provide insightful information on the ongoing respiratory impairment; in particular, atypical breathing patterns need to be recognized, as the application of current guidelines for sleep-related hypoxemia or sleep apnea may be insufficient for detecting early signs of diaphragmatic fatigue. We report the case of a 51-year-old man affected by ALS who was asymptomatic for breathing impairment, but whose nocturnal polysomnographic recording, despite not significant for obstructive sleep apnea nor for conventional hypoventilatory patterns, strongly suggested initial respiratory failure, as lately confirmed by the pulmonary follow-up. We discuss the advantages of including sleep recording in the clinical work-up of patients affected by ALS.

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.

Utility of Rectus Abdominis Ultrasound as a Respiratory Function Test for Amyotrophic Lateral Sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) causes deterioration of respiratory function. Muscle weakness of the orbicularis oris interferes with the accurate assessment of respiratory function using spirometry. Reduced forced vital capacity (FVC) is an indicator that helps determine the appropriate timing to provide noninvasive ventilation (NIV) for the survival of ALS patients. We employed ultrasonography to evaluate changes in respiratory function by measuring the thickness of the rectus abdominis (RA) muscle as a possible alternative to spirometry.

METHODS

Sixteen subjects with ALS were included in this study. The thickness of RA muscles was measured using ultrasonography, and respiratory fluctuations, such as vital capacity (VC), FVC, FEV₁, percentage of predicted VC (%VC), percentage of predicted FVC (%FVC), percentage of predicted FEV₁ (%FEV₁), and FEV₁/FVC, were evaluated using spirometry.

RESULTS

Sixteen subjects underwent assessment by ultrasonography. A positive correlation was observed between the percent change in RA muscle thickness evaluated from maximal expiration to maximal inspiration and %VC (P = .001), %FVC (P = .001), FEV₁ (P = .009), and %FEV₁ (P = .02).

CONCLUSIONS

RA ultrasonography was useful for predicting a reduction in VC in subjects with ALS and may help determine the best timing for introducing NIV.

Thoracic Excursion Is a Biomarker for Evaluating Respiratory Function in Amyotrophic Lateral Sclerosis

Objective

To evaluate the usefulness of thoracic excursion as a biomarker in patients with amyotrophic lateral sclerosis (ALS).

Methods

We measured the forced the vital capacity (FVC), thoracic excursion, baseline-to-peak diaphragmatic compound muscle action potential (DCMAP) amplitude, diaphragm thickness at full inspiration (DTfi), Medical Research Council (MRC) sum score for muscle strength, and arterial partial pressures of oxygen and carbon dioxide and administered the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) and modified Medical Research Council (mMRC) Dyspnea Scale. The test–retest reliability of thoracic excursion was determined.

Results and Conclusions

Thirty-four patients with ALS and 26 age- and sex-matched healthy participants were enrolled. Thoracic excursion measurement had excellent test–retest reliability (intraclass coefficient: 0.974). Thoracic excursion was more strongly correlated with FVC (r = 0.678, p < 0.001) than DCMAP amplitude (r = 0.501, p = 0.003) and DTfi (r = 0.597, p < 0.001). It was also correlated with ALSFRS-R score (r = 0.610, p < 0.001), MRC sum score (r = 0.470, p = 0.005), and mMRC Dyspnea Scale score (r = −0.446, p = 0.008) and was the most sensitive parameter for assessing dyspnea and FVC. Thoracic excursion decreased as FVC declined in the early and late stages, there were no differences in DCMAP amplitude and DTfi between the early and late stages, and ALSFRS-R score and MRC sum score decreased only in the late stage. Thoracic excursion was well correlated with respiratory function and is useful for predicting respiratory and general dysfunction in patients with ALS regardless of stage.

Home-monitoring of vital capacity in people with a motor neuron disease

Background

Home-monitoring of spirometry has the potential to improve care for patients with a motor neuron disease (MND) by enabling early detection of respiratory dysfunction and reducing travel burden. Our aim was to evaluate the validity and feasibility of home-monitoring vital capacity (VC) in patients with MND.

Methods

We included 33 patients with amyotrophic lateral sclerosis, progressive muscular atrophy or primary lateral sclerosis who completed a 12-week home-monitoring protocol, consisting of 4-weekly unsupervised home assessments of VC and a functional rating scale. At baseline, during a home visit, patients/caregivers were trained in performing a VC test, and the investigator performed a supervised VC test, which was repeated at final follow-up during a second home visit. Validity of the unsupervised VC tests was evaluated by the differences between supervised and unsupervised VC tests, and through Bland–Altman 95% limits-of-agreement. Feasibility was assessed by means of a survey of user-experiences.

Results

The 95% limits-of-agreement were [− 14.3; 11.7] %predicted VC, and 88% of unsupervised VC tests fell within 10%predicted of supervised VC. 88% of patients experienced VC testing as easy and not burdensome, however, 15% patients did not think their VC test was performed as well as in the clinic. 94% of patients would like home-monitoring of VC in MND care.

Discussion

Unsupervised VC testing at home, with prior face-to-face training, is a valid and time-efficient method for the remote monitoring of respiratory function, and well-accepted by patients with MND and their caregivers.

Medical therapies for amyotrophic lateral sclerosis-related respiratory decline: an appraisal of needs, opportunities and obstacles

A roundtable convened in July 2020 examined issues concerning respiratory support in amyotrophic lateral sclerosis (ALS), with reference to the potential for an early-phase orally administered medication that might either postpone the introduction of noninvasive ventilation (NIV) and/or enhance the benefits to be gained from it. Attention was also given to the impact of the COVID-19 pandemic on usual practice in the assessment and management of ALS-related respiratory difficulties. Implementation of NIV marks a step-change in clinical status for patients and a major increase in burden for caregivers. All means to ease this transition should be explored: an oral therapy that supported respiratory function and patients' independence and sense of well-being would aid discussions to facilitate the eventual successful introduction of NIV. Assessment of a candidate oral therapy that might support respiratory function in ALS patients would be aided by the development of improved patient-reported outcome measures for robust quantification of treatment effect and quality of life. Such instruments could also be used to monitor patients' status during the COVID-19 pandemic, averting some of the risks of face-to-face assessment plus the patient burden and costs of traditional methods. Several oral candidate therapies have recently failed to meet their primary endpoints in clinical trials. However, understanding of the underlying physiology and appropriate trial design have grown and will inform future developments in this field.

Validity and reliability of the Turkish version of "the Dyspnea-ALS-Scale (DALS-15)"

AIM

The aim of this study was to investigate the validity and reliability of the Turkish version of The Dyspnea-ALS-Scale (DALS-15).

METHODS

Forward translation, back translation, and cross-cultural adaptation were used to ensure the equivalency of translated version of the scale. Then, patients with amyotrophic lateral sclerosis (ALS) who have dyspnea or orthopnea that develops with effort or at rest were evaluated using DALS-15 via online surveys. The respiratory subscale of ALS Functional Rating Scale-Revised (ALSFRS-R) and Modified Borg Dyspnea Scale (MBDS) was used to investigate the construct validity of the Turkish DALS-15. Reliability was assessed with Cronbach's α and inter-item correlation matrix (internal consistency).

RESULTS

We have included 52 ALS patients in the study. Findings showed that Turkish version of DALS-15 was highly correlated with respiratory subscale of ALSFRS-R (r =  - 0.668; p =  < 0.0001) and MBDS (for upright position: r = 0.728; p =  < 0.0001 and for supine: r = 0.78; p =  < 0.0001). The scale did not show any ceiling or floor effect. Also, DALS-15 had a high level of Cronbach's α (0.95) and internal consistency (ICC: 0.949; 95%CI: 0.92-0.96). Test-re-test reliability of the questionnaire was (ICC: 0.909; 95% CI: 0.81-0.95). The standard error of measurement value was 2.76, whereas the minimal detectable change score was 7.66 points for the translated version of the scale.

CONCLUSIONS

The Turkish version of DALS-15 possesses strong psychometric properties with excellent validity and reliability. It is shown to be useful for online self-assessment, outside of the clinical settings, especially in hard times such as a pandemic.

Respiratory parameters on diagnostic sleep studies predict survival in patients with amyotrophic lateral sclerosis

OBJECTIVE

In amyotrophic lateral sclerosis (ALS), respiratory muscle involvement and sleep-disordered breathing relate to worse prognosis. The present study investigated whether respiratory outcomes on first-ever sleep studies predict survival in patients with ALS, specifically taking into account subsequent initiation of non-invasive ventilation (NIV).

METHODS

From patients with ALS, baseline sleep study records, transcutaneous capnometry, early morning blood gas analysis, survival data and clinical disease characteristics were retrospectively analyzed. Patients were stratified according to whether enduring NIV was consecutively established ("NIV(+)") or not ("NIV(-)").

RESULTS

Among the study cohort (n = 158, 72 female, 51 with bulbar onset ALS, 105 deceased) sleep-disordered breathing was present at baseline evaluation in 97 patients. Early morning base excess (EMBE) > 2 mmol/l predicted nocturnal hypercapnia. Ninety-five patients were NIV(+) and 63 were NIV(-). Survival from baseline sleep studies was significantly reduced in NIV(-) but not in NIV(+) patients with nocturnal CO₂ tension ≥ 50 mmHg, apnea hypopnea index ≥ 5/h, and EMBE > 2 mmol/l. Hazard ratio for EMBE > 2 mmol/l was increased in NIV(-) patients only, and EMBE independently predicted survival in both NIV(-) and NIV(+) patients. Furthermore, EMBE on baseline sleep studies was the only predictor for survival from symptom onset, and hazard ratio for shorter survival was markedly higher in the NIV(-) than the NIV(+) group (2.85, p = 0.005, vs. 1.71, p = 0.042).

INTERPRETATION

In patients with ALS, EMBE > 2 mmol/l predicts nocturnal hypercapnia and shorter survival. Negative effects of sleep-disordered breathing on survival are statistically abolished by sustained NIV.

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

INTRODUCTION

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Noninvasive Ventilation in Amyotrophic Lateral Sclerosis

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

Diaphragmatic dysfunction at the first visit to a chest diseases outpatient clinic in 500 patients with amyotrophic lateral sclerosis

INTRODUCTION

In this study, we aimed to evaluate diaphragmatic dysfunction (DD) by using a practical approach in patients with amyotrophic lateral sclerosis (ALS) at the first visit to a chest diseases outpatient clinic.

METHODS

Patients with ALS seen in our outpatient clinic for the past 5 y and followed up for at least 1 y, were retrospectively evaluated. Having at least one of the following three criteria was accepted as DD: (a) paradoxical abdominal movement (PAM), (b) sitting-supine forced vital capacity (FVC) difference ≥ 20%, (c) sitting-supine arterial oxygen saturation measured by pulse oximetry (SpO₂ ) difference ≥ 4%. Respiratory symptoms, arterial blood gas analysis, sleep studies, noninvasive mechanical ventilation use, and mortality were recorded.

RESULTS

Five-hundred patients with ALS were included (female/male: 220/280, age: 58.9 ± 11.3 y). Of the patients, 22.8% had daytime hypercapnia. DD was observed in 55% of the patients (PAM in 112, sitting-supine FVC difference ≥ 20% in 50, and sitting-supine SpO₂ difference ≥ 4% in 113 patients). Of the patients with DD, 31.6% (n = 87) had no respiratory symptoms, 46.4% had FVC > 70% and 33.5% had FVC <50%. Nocturnal hypoxemia (sleep time spent with SpO₂  < 90% ≥30%) was present in 59.7%, and all patients with nocturnal hypoxemia had DD. Obstructive sleep apnea (8 severe, 14 moderate, 39 mild) was detected in 55% of the patients with polysomnography (n = 61) or polygraphy (n = 50). During follow-up, 52.2% of the patients died. Mean survival time was shorter in patients with DD (P < .001).

CONCLUSION

Paradoxical abdomimal movement (PAM), sitting-supine SpO₂ difference ≥ 4% and sitting-supine FVC difference ≥ 20% are indicators of DD, which should be routinely evaluated at every outpatient visit.

Long-term noninvasive ventilation in COPD: current evidence and future directions

Introduction: Long-term noninvasive ventilation (NIV) is an established treatment for end-stage COPD patients suffering from chronic hypercapnic respiratory failure. This is reflected by its prominent position in national and international medical guidelines. Areas covered: In recent years, novel developments in technology such as auto-titrating machines and hybrid modes have emerged, and when combined with advances in information and communication technologies, these developments have served to improve the level of NIV-based care. Such progress has largely been instigated by the fact that healthcare systems are now confronted with an increase in the number of patients, which has led to the need for a change in current infrastructures. This article discusses the current practices and recent trends, and offers a glimpse into the future possibilities and requirements associated with this form of ventilation therapy. Expert opinion: Noninvasive ventilation is an established and increasingly used treatment option for patients with chronic hypercapnic COPD and those with persistent hypercapnia following acute hypercapnic lung failure. The main target is to augment alveolar hypoventilation by reducing P_aCO₂ to relieve symptoms. Nevertheless, when dealing with severely impaired patients, it appears necessary to switch the focus to patient-related outcomes such as health-related quality of life.

Triage of Amyotrophic Lateral Sclerosis Patients during the COVID-19 Pandemic: An Application of the D50 Model

Amyotrophic lateral sclerosis (ALS) is a progressive neuromuscular disease, the management of which requires the continuous provision of multidisciplinary therapies. Owing to the novel coronavirus disease (COVID-19) pandemic, regular contact with ALS patients at our center was severely restricted and patient care was at risk by delay of supportive therapies. We established a triage system based on the D50 disease progression model and were thus able to identify a prospective cohort with high disease aggressiveness (D50 < 30). Thirty-seven patients with highly aggressive disease were actively offered follow-up, either via telephone or on-site, depending on their disease-specific needs and abilities. We describe here the procedures, obstacles, and results of these prescient efforts during the restrictions caused by COVID-19 in the period between March and June 2020. In conclusion, four patients with highly aggressive disease were initiated with non-invasive ventilation and two received a gastrostomy. We could show that a comparable amount of advanced care was induced in a retrospective cohort within a similar time period one year prior to the COVID-19 outbreak. Our workflow to identify high-risk patients via D50 model metrics can be easily implemented and integrated within existing centers. It helped to maintain a high quality of advanced care planning for our ALS patients.

Dyspnea as a Fatigue-Promoting Factor in ALS and the Role of Objective Indicators of Respiratory Impairment

CONTEXT

There is no evidence-based treatment for fatigue in amyotrophic lateral sclerosis (ALS), and identification of treatable causes determines management strategies. Although dyspnea is a key symptom of ALS and effectively treatable, it has not been sufficiently investigated whether dyspnea may be a fatigue-promoting factor.

OBJECTIVES

To determine the level of fatigue in dyspneic ALS patients and whether fatigue is promoted by dyspnea. We further evaluated the correlation of fatigue with respiratory function tests.

METHODS

About 101 dyspneic patients and 20 matched controls completed the ALS Functional Rating Scale-Extension and the Fatigue Severity Scale. Dyspneic patients additionally completed the Dyspnea-ALS Scale and the ALS Assessment Questionnaire and underwent respiratory function tests (forced vital capacity, sniff nasal inspiratory pressure, mean inspiratory and expiratory pressure with respective relaxation rates, and blood gases). Multiple regression and correlation analyses were conducted.

RESULTS

Dyspneic patients had significantly higher fatigue scores than nondyspneic patients, and their fatigue significantly affected quality of life. Dyspnea alone explained up to 24% of the variance in fatigue. No associations were observed between fatigue and respiratory function tests. Patients with noninvasive ventilation reported significantly more dyspnea and fatigue.

CONCLUSION

Fatigue is a frequent and bothersome symptom in dyspneic ALS patients. Dyspnea-related distress is, in contrast to objective indicators of respiratory impairment, a determining factor of experienced fatigue. There is an urgent need for further symptom relief beyond noninvasive ventilation. Adequate treatment of dyspnea has the potential for synergies in symptom management arising from the association between fatigue and dyspnea.

Effects of noninvasive ventilation in amyotrophic lateral sclerosis: The complication of bulbar impairment

Amyotrophic lateral sclerosis is a neurodegenerative illness that causes gradual loss of muscle function. Patients eventually develop bulbar impairment, requiring extensive respiratory support. Noninvasive ventilation (NIV) has gained attention as an easily accessible method with promising benefits. We conducted this systematic review to outline the therapeutic effects of NIV, add to previous publications discussing this topic by providing updates on newly completed and ongoing studies, and identify limitations that must be addressed in future trials. A search of PubMed and Cochran for relevant primary studies yielded 26 publications. Studies indicate NIV use is associated with improvements in quality of life, regardless of the severity of bulbar impairment. However, NIV’s benefits on survival were limited to patients with less bulbar impairment. In addition, our review found several limitations that undermine the efforts to establish a definitive treatment regimen. Future studies will need to address these problems in order to provide patients with better respiratory care.

The upper cervical spinal cord in ALS assessed by cross-sectional and longitudinal 3T MRI

The upper cervical spinal cord is measured in a large longitudinal amyotrophic lateral sclerosis (ALS) cohort to evaluate its role as a biomarker. Specifically, the cervical spinal cord´s cross-sectional area (CSA) in plane of the segments C1–C3 was measured semi-automatically with T1-weighted 3T MRI sequences in 158 ALS patients and 86 controls. Six-month longitudinal follow-up MRI scans were analyzed in 103 patients. Compared to controls, in ALS there was a significant mean spinal cord atrophy (63.8 mm² vs. 60.8 mm², p = 0.001) which showed a trend towards worsening over time (mean spinal cord CSA decrease from 61.4 mm² to 60.6 mm² after 6 months, p = 0.06). Findings were most pronounced in the caudal segments of the upper cervical spinal cord and in limb-onset ALS. Baseline CSA was related to the revised ALS functional rating scale, disease duration, precentral gyrus thickness and total brain gray matter volume. In conclusion, spinal cord atrophy as assessed in brain MRIs in ALS patients mirrors the extent of overall neurodegeneration and parallels disease severity.

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.

Dyspnea in amyotrophic lateral sclerosis: The Dyspnea-ALS-Scale (DALS-15) essentially contributes to the diagnosis of respiratory impairment

BACKGROUND

Dyspnea is a cardinal but often underestimated symptom in amyotrophic lateral sclerosis (ALS). The newly developed Dyspnea-ALS-Scale (DALS-15) is highly relevant for therapeutic decisions because dyspnea is a separate criterion to consider noninvasive ventilation (NIV) in ALS. In comparison to the limited effects of neuroprotective compounds, NIV has the greatest impact on survival and improves quality of life.

OBJECTIVE

To investigate whether dyspnea corresponds to parameters of respiratory status mainly used in clinical neurological practice. We also investigated if the DALS-15 could help identify patients for consideration of NIV in whom neither spirometry nor blood gas parameters indicate the need for NIV (forced vital capacity (FVC) < 50% or probable <75%, pCO₂ ≥45  mmHg).

METHODS

Seventy ALS patients with dyspnea according to the DALS-15 obtained blood gas analysis and spirometry (FVC in sitting and supine positions). The supine decline in FVC was calculated.

RESULTS

There was no linear relationship between dyspnea and spirometry as well as blood gases. 83% of our patients had an upright FVC still greater than 50% and no daytime hypercapnia.

CONCLUSIONS

Our study clearly shows that dyspnea can occur independently of objective indicators of respiratory impairment like spirometry or blood gases. Hence, the DALS-15 covers another aspect of respiratory impairment than these tests and refers to the subjective component of respiratory impairment. It detects dyspnea in a considerable proportion of patients in whom NIV should thus be considered although their spirometric and blood gas results do not point towards NIV. The DALS-15 therefore may help to improve the stratification of patients with respiratory impairment for more efficient symptom management and timely coordination of care.

The Dyspnea-ALS-Scale (DALS-15) optimizes individual treatment in patients with amyotrophic lateral sclerosis (ALS) suffering from dyspnea

BACKGROUND

Dyspnea is frequent in amyotrophic lateral sclerosis (ALS) and one of the most bothersome symptoms. The recently developed Dyspnea-ALS-Scale (DALS-15) is a disease-specific patient-reported outcome to detect and quantify dyspnea.

OBJECTIVES

To analyze in a case-based approach the diagnostic and clinical implications and the benefit of the DALS-15 for individual patients in daily clinical routine.

METHODS

Dyspnea was assessed by the 15-item comprising DALS-15 in two patients with ALS. Spirometry was performed and blood gases were analyzed. Results were evaluated in the clinical context of the respective patients.

RESULTS

In one patient the presence of dyspnea detected by the DALS-15 indicated noninvasive ventilation (NIV) although forced vital capacity (FVC) and blood gas analysis were well preserved. After NIV implementation, the DALS-15 was helpful to determine the patient's need for medication, the timing of NIV titration and the adaptation of NIV sessions. In another patient, who was anarthric and no longer able to perform spirometry due to severe bulbar impairment, the DALS-15 allowed a standardized assessment of dyspnea-related distress independently of bulbar dysfunction.

CONCLUSION

The DALS-15 provides a deeper insight into the respiratory status of individual patients. It helps to diagnose respiratory impairment in patients in whom NIV should be considered although FVC and blood gas results do not reveal indication for NIV. It is also valuable for the guidance of patients in later stages of respiratory impairment when NIV is already implemented, and in patients with severe bulbar dysfunction. The DALS-15 can improve specific symptom management and coordination of care and therefore has the potential to optimize individual treatment in ALS patients with dyspnea.

Dyspnea in Amyotrophic Lateral Sclerosis: Rasch-Based Development and Validation of a Patient-Reported Outcome (DALS-15)

CONTEXT

Dyspnea is a cardinal but often underestimated symptom in amyotrophic lateral sclerosis (ALS). The lack of a satisfying assessment tool leads to diagnostic uncertainty and bears the risk that established life-prolonging and symptom-relieving therapeutic options will not be adequately applied.

OBJECTIVES

The objective of this study was to develop and validate a German language disease-specific patient-reported outcome measure to assess dyspnea in ALS by combination of a qualitative and quantitative approach using Rasch analysis.

METHODS

Based on input from clinical experts and patients, a preliminary 35-item questionnaire was developed and completed by 94 patients with ALS having dyspnea. Data were subjected to Rasch analysis and tested for required measurement issues such as appropriate response categories, the absence of differential item functioning, local independence, and unidimensionality.

RESULTS

After iterative Rasch analyses, the final 15-item Dyspnea-ALS-Scale (DALS-15) was obtained. The scale satisfies the axioms of the Rasch model with good fit statistics, the absence of local dependency, and differential item functioning as well as acceptable unidimensionality. The DALS-15 is optimally targeted and suitable for group and individual use. It shows excellent test-retest reliability and convergent validity.

CONCLUSION

The DALS-15 satisfies strictest modern measurement criteria and has interval scale properties. It fills an important gap in assessment and could be most helpful to optimize symptom management in patients with ALS.

Reliability of autonomic activations as surrogates of cortical arousals in ventilated patients affected by amyotrophic lateral sclerosis

PURPOSE

The study aims to evaluate the performance of autonomic activations as a tool to assess sleep fragmentation and to recognize hypopneas in patients with amyotrophic lateral sclerosis (ALS) under non-invasive mechanical ventilation and secondarily, to evaluate, in patients with the same disease, the relationship between disruption of autonomic nervous system (ANS) activity and the usefulness of the autonomic activations as surrogates of cortical arousals.

METHODS

Sixteen ALS patients underwent simultaneous polysomnography and portable cardiorespiratory monitoring (PM). On the polysomnography, standard rules were used for scoring arousals and respiratory events. On the PM, autonomic arousals were scored as ≥ 15% heart rate (HR) increase with a ≥ 35% pulse wave amplitude (PWA) reduction, HR increase ≥ 20%, or PWA decrease ≥ 40%. Nocturnal HR variability was analyzed in the ALS patients and in 11 control subjects as an index of ANS activity.

RESULTS

Synchronized epoch by epoch analysis of the polysomnography and PM recordings showed that only 31.0 (22.5-58.7)% cortical and 36.1 (20.5-47.2)% autonomic arousals were associated with one another. Among hypopneas scored at polysomnography, 71.7% were associated with a cortical arousal but not with a desaturation. On average, HR variability in ALS showed signs of depressed ANS activity that was particularly evident in the patients where the cortical arousals exceeded the autonomic ones.

CONCLUSIONS

In ventilated ALS patients, autonomic activations may hardly have a role as surrogates of cortical arousals for assessment of sleep fragmentation and for respiratory scoring. Depression of ANS activity may be related to their poor performance.

Impact of home mechanical ventilation on sleep quality

PURPOSE OF REVIEW

The number of patients receiving home mechanical ventilation (HMV) has dramatically increased in recent years. Although physiological parameters, health-related quality of life and long-term outcomes frequently serve as primary outcomes, only a few studies have primarily addressed sleep quality in patients undergoing HMV. Therefore, this review article summarizes the current knowledge on sleep quality in patients receiving HMV.

RECENT FINDINGS

HMV can be performed noninvasively via face masks or invasively via tracheal cannulas. Studies in patients receiving invasive HMV therapy are clearly lacking. Most studies in this field have focused on invasively ventilated patients in the ICU, but the findings are not necessarily applicable to patients undergoing invasive HMV. On the other hand, there are several trials showing that noninvasive ventilation (NIV) has the potential to improve sleep quality in patients with severe sleep disturbances associated with chronic hypercapnic respiratory failure. To this end, both subjectively and objectively assessed sleep qualities by polysomnography are reported to improve after long-term NIV is initiated.

SUMMARY

Although HMV has the potential to improve sleep quality in patients with chronic hypercapnic respiratory failure, it can also have a negative impact on sleep quality, particularly in cases of patient-ventilator asynchrony or leakage. Therefore, both subjective and objective polysomnographic assessments of sleep quality should become an integral part of managing patients who receive HMV therapy.

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.

Breathing: Motor Control of Diaphragm Muscle

Breathing occurs without thought but is controlled by a complex neural network with a final output of phrenic motor neurons activating diaphragm muscle fibers (i.e., motor units). This review considers diaphragm motor unit organization and how they are controlled during breathing as well as during expulsive behaviors.