Nocturnal oximetry: utility in the respiratory management of amyotrophic lateral sclerosis

Use of the combination of spirometry, arterial blood gas analysis and overnight oximetry to predict the outcomes of patients affected by motor neuron disease: The Milan-Torin respiratory score (Mi-To-RS)

BACKGROUND AND PURPOSE

The use of multiple tests, including spirometry, arterial blood gas (ABG) analysis and overnight oximetry (OvOx), is highly recommended to monitor the respiratory function of patients with motor neuron disease (MND). In this study, we propose a composite score to simplify the respiratory management of MND patients and better stratify their prognosis.

MATERIALS AND METHODS

We screened the clinical charts of 471 non-ventilated MND patients referred to the Neuro-rehabilitation Unit of the San Raffaele Scientific Institute of Milan (January 2001-December 2019), collecting spirometric, ABG and OvOx parameters. To evaluate the prognostic role of each measurement, univariate Cox regression for death/tracheostomy was performed, and the variables associated with survival were selected to design a scoring system. Univariate and multivariate Cox regression analyses were then carried out to evaluate the prognostic role of the score. Finally, results were replicated in an independent cohort from the Turin ALS Center.

RESULTS

The study population included 450 patients. Six measurements were found to be significantly associated with survival and were selected to design a scoring system (maximum score = 8 points). Kaplan-Meier analysis showed significant stratification of survival and time to non-invasive mechanical ventilation adaptation according to score values, and multivariate analysis confirmed the independent effect of the respiratory score on survival of each cohort.

CONCLUSION

Forced vital capacity, ABG and OvOx parameters provide complementary information for the respiratory management and prognosis of MND patients and the combination of these parameters into a single score might help neurologists predict prognosis and guide decisions on the timing of the implementation of different diagnostic or therapeutic approaches.

Comparative Performance of Different Respiratory Test Parameters for Detection of Early Respiratory Insufficiency in Patients With ALS

OBJECTIVE

To compare the performance of different respiratory function testing in a multidisciplinary ALS clinic.

METHODS

Demographics, clinical data, and respiratory testing parameters were abstracted from the medical records of patients who attended a multidisciplinary ALS clinic from 2008-2016. We compared the performance of the three primary respiratory test parameters used by Medicare for the initiation of non-invasive ventilation (NIV), (forced vital capacity (FVC) < 50% predicted, maximum inspiratory pressure (MIP) < 60 cm H20, and abnormal overnight pulse oximetry (OvOx)) on how they related to several clinically relevant attributes.

RESULTS

476 subjects were identified who underwent at least one respiratory test. Abnormalities of OvOx, MIP, and FVC occurred at a median of 1.6, 1.5, and 3.8 years from disease onset, respectively (p < 0.00001). Subjects with bulbar-onset ALS exhibited earlier abnormalities in MIP and FVC than in spinal-onset ALS (p <0.005). The median survival after an abnormal OvOx, MIP, or FVC test was 1.4, 1.4, and 0.9 years, respectively (p < 0.0001). Utilizing the ALS Functional Rating Score respiratory subscales, at the time of reported respiratory symptoms there were abnormalities in OvOx (60%), MIP (69%), and FVC (19%). Conversely, when respiratory parameter abnormalities preceded reported respiratory symptoms, this occurred with frequencies in OvOx (79%), MIP (42%) or FVC (24%). Four hundred forty-three subjects (93.1%) developed at least one abnormal respiratory measure meeting Medicare criteria for NIV consideration, but fewer than 50% in our cohort demonstrated NIV use. Improved survival in subjects using NIV was statistically significant in patients with bulbar-onset ALS.

CONCLUSIONS

Abnormalities in OvOx and MIP perform better than FVC at early detection of neuromuscular respiratory weakness in ALS. Initiation of NIV in patients with respiratory insufficiency may improve overall survival in ALS. In the setting of the COVID-19 pandemic, FVC and MIP have not been routinely performed due to infectious aerosol generation. OvOx, which we now routinely mail to patients' homes, has been utilized exclusively during the COVID-19 pandemic, and allows for continued remote monitoring of respiratory status of patients with ALS.

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.

The uses of overnight pulse oximetry

Overnight pulse oximetry (OPO) has proven to be an effective and beneficial technique to determine the cardiorespiratory status of patients in both the inpatient and outpatient settings. It is a cheap, safe, reliable, simple, and accurate method of patient monitoring as compared to the expensive and labor-intensive method of multichannel polysomnography for detecting sleep-disordered breathing. It provides accurate information about patient's oxygenation status and also helps in monitoring the response to continuous positive airway pressure and in the surgical treatment of obstructive sleep apnea (OSA). Nocturnal hypoxemia portends a poor prognosis in patients of chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD), and neuromuscular diseases. OPO can help its early detection and management.

Amyotrophic Lateral Sclerosis and the Respiratory System

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that always affects the respiratory muscles. It is characterized by degeneration of motor neurons in the brain and spinal cord. Respiratory complications are the most common causes of death in ALS and typically occur within 3 to 5 years of diagnosis. Because ALS affects both upper and lower motor neurons, it causes hyperreflexia, spasticity, muscle fasciculations, muscle atrophy, and weakness. It ultimately progresses to functional quadriplegia. ALS most commonly begins in the limbs, but in about one-third of cases it begins in the bulbar muscles responsible for speech and swallowing.

Sleep–wake problems in patients with amyotrophic lateral sclerosis: implications for patient management

SUMMARY Sleep–wake problems are frequent, although unrecognized, complications of amyotrophic lateral sclerosis (ALS). Sleep disorders such as insomnia, sleep-disordered breathing and restless legs syndrome have all been reported in patients with ALS, despite the limited number of studies and the small populations investigated so far. Sleep disturbances gradually worsen with disease progression, suggesting a relationship between the severity of disease and the neurodegenerative process. However, poor sleep can also be a consequence of several disturbances such as anxiety, depression, pain, choking, sialorrhea, fasciculations, cramps, nocturia and the inability to get comfortable and move freely in bed. Sleep disorders may have many reflections on patients with ALS, including excessive daytime somnolence, fatigue, impaired cognition, reduced quality of life and survival. This article reviews the recent literature on sleep–wake problems in patients with ALS, focusing on the implications for patient management.

Nocturnal home pulse oximetry: variability and clinical implications in home mechanical ventilation

BACKGROUND

Nocturnal home pulse oximetry (NHPO) provides information by measuring a series of variables: time spent with SaO(2) <90% expressed as percentage (T90) or in minutes (Tm90), mean SaO(2) (MnS), and lowest SaO(2) (LwS.) The presence of significant nocturnal desaturation has been proposed as a parameter in decision making with regard to initiating home mechanical ventilation (HMV) or monitoring HMV effectiveness. However, there is limited information on the possible variability of the test, and this could influence the interpretation of results.

OBJECTIVES

To explore the variability between 2 consecutive measurements of NHPO and to determine clinical applications in HMV.

METHODS

The patients presented diseases susceptible to HMV treatment and were enrolled in stable condition without respiratory failure. NHPO was conducted on 2 consecutive nights. The variables analyzed were: T90, Tm90, Mns, and LwS. The coefficient of variation (CV), a concordance coefficient (CC), and the Bland-Altman method were used in order to explore the variability.

RESULTS

We studied 40 cases. Two were excluded, and the remaining 38 were aged 58 ± 16 years (19 males). Eighteen were receiving HMV. CV values exceeded 100% for T90 and Tm90 and were below 5% for MnS and LwS. The CC for T90, Tm90, and LwS showed confidence intervals with lower limits below 0.5, while for MnS the value was 0.88 (0.79-0.93).

CONCLUSIONS

There is a wide variability in NHPO recordings for T90, Tm90, and LwS, so a single determination to detect nocturnal desaturation may not be valid for decision making; the parameter with the least interindividual variability and intraindividual variability was MnS.

Practice parameter update: the care of the patient with amyotrophic lateral sclerosis: drug, nutritional, and respiratory therapies (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology

OBJECTIVE

To systematically review evidence bearing on the management of patients with amyotrophic lateral sclerosis (ALS).

METHODS

The authors analyzed studies from 1998 to 2007 to update the 1999 practice parameter. Topics covered in this section include slowing disease progression, nutrition, and respiratory management for patients with ALS.

RESULTS

The authors identified 8 Class I studies, 5 Class II studies, and 43 Class III studies in ALS. Important treatments are available for patients with ALS that are underutilized. Noninvasive ventilation (NIV), percutaneous endoscopic gastrostomy (PEG), and riluzole are particularly important and have the best evidence. More studies are needed to examine the best tests of respiratory function in ALS, as well as the optimal time for starting PEG, the impact of PEG on quality of life and survival, and the effect of vitamins and supplements on ALS.

RECOMMENDATIONS

Riluzole should be offered to slow disease progression (Level A). PEG should be considered to stabilize weight and to prolong survival in patients with ALS (Level B). NIV should be considered to treat respiratory insufficiency in order to lengthen survival (Level B) and to slow the decline of forced vital capacity (Level B). NIV may be considered to improve quality of life (Level C) [corrected].Early initiation of NIV may increase compliance (Level C), and insufflation/exsufflation may be considered to help clear secretions (Level C).

[Mechanisms of deregulated response to hypoxia in sporadic amyotrophic lateral sclerosis: a clinical study]

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder of upper and lower motorneurons, leading to death in 3 to 5 years. Respiratory insufficiency and hypoxemia are closely linked during the clinical course of ALS. Chronic respiratory insufficiency and hypoxemia generally occur late in the disease course but rapid episodes of intermittent hypoxemia followed by reoxygenation can occur early and insidiously. Two pathways are involved in the response to hypoxemia: (i) hypoxia inducible factor-1 (HIF-1) and VEGF/HIF-2 and an erythropoietin (EPO) mediated pathway, in response to prolonged hypoxemia; and (ii) nuclear factor kappa-B (NFkappa-B) during acute hypoxemia followed by reoxygenation episodes, inducing inflammatory mediators: interleukin-6 (IL-6), TNF-alpha, cyclo oxygenase-2 (COX-2) and prostaglandin E-2 (PGE-2). Our aim was to specify the role of the different functional pathways of response to hypoxemia in sporadic ALS patients, compared with neurological controls and according to the level of hypoxemia. We report the results of several studies of hypoxemic and/or inflammatory mediators in the cerebrospinal fluid (CSF) from ALS patients, according to their respiratory status, showing a selective defect of HIF-1 mediated angiogenic factors (VEGF and angiogenin [ANG]) during chronic hypoxia in sporadic ALS patients, compared to hypoxemic neurological controls; contrasting with an early activation of the NFkappa-B pathway since the isolated desaturation stage (IL-6, TNF-alpha, PGE-2, angiopoietin-2) in the same cohort of sporadic ALS patients. All these results are consistent with a selective impairment of the HIF-1 pathway during chronic hypoxemia in ALS patients. Inflammatory mediators were strongly elevated, since the early stage of the disease until chronic hypoxemia, suggesting a compensatory mechanism.

Palliative care in amyotrophic lateral sclerosis, Parkinson's disease, and multiple sclerosis

BACKGROUND

Amyotrophic lateral sclerosis, Parkinson's disease, atypical parkinsonian syndromes, and multiple sclerosis are progressive neurologic disorders that cumulatively afflict a large number of people. Effective end-of-life palliative care depends upon an understanding of the clinical aspects of each of these disorders.

OBJECTIVES

The authors review the unique and overlapping aspects of each of these disorders with an emphasis upon the clinical management of symptoms.

DESIGN

The authors review current management and the supporting literature.

CONCLUSIONS

Clinicians have many effective therapeutic options to choose from when managing the symptoms produced by these disorders.

Management guidelines for motor neurone disease patients on non-invasive ventilation at home

Most motor neurone disease (MND) patients die of respiratory system complications. When patients have advanced disease with symptoms of respiratory failure, management issues can become complicated by the introduction of assisted ventilatory devices. Therefore, care provision by a multidisciplinary team must be structured and co-ordinated in order to ensure that patients and their carers receive the optimal level of care. The objective of this article is to review the literature and explore the complex issues surrounding the use of non-invasive positive pressure ventilation (NIPPV) in home care MND patients as a justification for the development of a management guideline for medical practitioners. A guideline for multidisciplinary care of home ventilated MND patients will be proposed.

Management strategies for patients with amyotrophic lateral sclerosis from diagnosis through death

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive neuromuscular disorder that is inevitably fatal. There are no effective treatments to stop or reverse the natural course of the disease. The role of the physician is to provide comfort and optimize quality of life.

REVIEW SUMMARY

Management of patients with ALS is a process extending over months to years. It begins with breaking the news of the diagnosis and extends through the terminal phase. Medication may extend lifespan by a small amount. However, most efforts are centered around symptom management. Areas of importance include respiration, nutrition, secretions, communication, pseudobulbar affect, therapy and exercise, spasticity and cramps, pain, depression and suicide, spirituality and religion, cognitive changes, the development of advance directives, and care at the end of life. Multidisciplinary ALS clinics provide much-needed support for patients with ALS and their caregivers.

CONCLUSION

Although physicians cannot cure ALS or even halt progression, there is much that can be done to manage the physical and emotional symptoms, thereby maintaining or enhancing quality of life.

Neuromuscular disorders and sleep

Neuromuscular disorders are caused by the primary involvement of the motor unit. In these patients, sleep-disordered breathing (SDB) due to respiratory muscle weakness is often encountered during sleep. Because there is a tendency to overlook this disorder, all patients with neuromuscular disorders should be questioned about SDB. Overnight polysomnography is the best investigation for SDB and nocturnal desaturations. In the management of these patients, noninvasive intermittent positive pressure ventilation results in improvement of SDB and breathing.