Nocturnal pulse oximetry: a new approach to establish the appropriate time for non-invasive ventilation in ALS patients

EFNS guidelines on the clinical management of amyotrophic lateral sclerosis (MALS)--revised report of an EFNS task force

BACKGROUND

The evidence base for the diagnosis and management of amyotrophic lateral sclerosis (ALS) is weak.

OBJECTIVES

To provide evidence-based or expert recommendations for the diagnosis and management of ALS based on a literature search and the consensus of an expert panel.

METHODS

All available medical reference systems were searched, and original papers, meta-analyses, review papers, book chapters and guidelines recommendations were reviewed. The final literature search was performed in February 2011. Recommendations were reached by consensus.

RECOMMENDATIONS

Patients with symptoms suggestive of ALS should be assessed as soon as possible by an experienced neurologist. Early diagnosis should be pursued, and investigations, including neurophysiology, performed with a high priority. The patient should be informed of the diagnosis by a consultant with a good knowledge of the patient and the disease. Following diagnosis, the patient and relatives/carers should receive regular support from a multidisciplinary care team. Medication with riluzole should be initiated as early as possible. Control of symptoms such as sialorrhoea, thick mucus, emotional lability, cramps, spasticity and pain should be attempted. Percutaneous endoscopic gastrostomy feeding improves nutrition and quality of life, and gastrostomy tubes should be placed before respiratory insufficiency develops. Non-invasive positive-pressure ventilation also improves survival and quality of life. Maintaining the patient's ability to communicate is essential. During the entire course of the disease, every effort should be made to maintain patient autonomy. Advance directives for palliative end-of-life care should be discussed early with the patient and carers, respecting the patient's social and cultural background.

Home mechanical ventilation: a Canadian Thoracic Society clinical practice guideline

Increasing numbers of patients are surviving episodes of prolonged mechanical ventilation or benefitting from the recent availability of userfriendly noninvasive ventilators. Although many publications pertaining to specific aspects of home mechanical ventilation (HMV) exist, very few comprehensive guidelines that bring together all of the current literature on patients at risk for or using mechanical ventilatory support are available. The Canadian Thoracic Society HMV Guideline Committee has reviewed the available English literature on topics related to HMV in adults, and completed a detailed guideline that will help standardize and improve the assessment and management of individuals requiring noninvasive or invasive HMV. The guideline provides a disease-specific review of illnesses including amyotrophic lateral sclerosis, spinal cord injury, muscular dystrophies, myotonic dystrophy, kyphoscoliosis, post-polio syndrome, central hypoventilation syndrome, obesity hypoventilation syndrome, and chronic obstructive pulmonary disease as well as important common themes such as airway clearance and the process of transition to home. The guidelines have been extensively reviewed by international experts, allied health professionals and target audiences. They will be updated on a regular basis to incorporate any new information.

Mechanical ventilation for amyotrophic lateral sclerosis/motor neuron disease

BACKGROUND

Amyotrophic lateral sclerosis, also known as motor neuron disease, is a fatal neurodegenerative disease. Without mechanical ventilation, death from respiratory failure usually follows within two to five years of the onset of symptoms.

OBJECTIVES

To examine the efficacy of mechanical ventilation (tracheostomy and non-invasive ventilation) in improving survival, on disease progression and quality of life in amyotrophic lateral sclerosis.

SEARCH STRATEGY

We searched The Cochrane Neuromuscular Disease Group Trials Specialized Register (December 8 2008), The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2008), MEDLINE (January 1966 to December 2008), EMBASE (January 1947 to December 2008), CINAHL Plus (January 1937 to December 2008), and AMED (January 1985 to December 2008). We also searched for ongoing studies on clinicaltrials.gov.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials involving non-invasive or tracheostomy assisted ventilation in participants with a clinical diagnosis of amyotrophic lateral sclerosis.

DATA COLLECTION AND ANALYSIS

Four authors independently selected studies for assessment. All authors extracted data independently from the full text of selected studies and assessed the risk of bias in studies that met the inclusion criteria. We attempted to obtain missing data where possible.

MAIN RESULTS

Two randomised controlled trials involving 54 participants receiving non-invasive ventilation were identified and included. Incomplete data were published for one study and we contacted the trial authors who were not able to provide the missing data. Therefore the results of the review were based on a single study of 41 participants. The study showed that the overall median survival in the whole cohort after initiation of assisted ventilation was significantly different between the non-invasive ventilation and standard care groups (P = 0.0062) with a median survival for the non-invasive ventilation group patients of 48 days longer than the standard care group participants. Non-invasive ventilation significantly improved survival and quality of life in the subgroup with normal to moderately impaired bulbar function. Non-invasive ventilation did not prolong survival in patients with poor bulbar function although it showed significant improvement in the mean symptoms domain of the sleep apnoea quality-of-life index but not in the Short Form-36 quality of life mental component summary score .

AUTHORS' CONCLUSIONS

Evidence from a single randomised trial of non-invasive ventilation in 41 participants suggests that it significantly prolongs survival and improves or maintains quality of life in people with ALS. Survival and some measures of quality of life were significantly improved in the subgroup of people with better bulbar function, but not in those with severe bulbar impairment.

Prognostic factors in ALS: A critical review

We have performed a systematic review to summarize current knowledge concerning factors related to survival in ALS and to evaluate the implications of these data for clinical trials design. The median survival time from onset to death ranges from 20 to 48 months, but 10-20% of ALS patients have a survival longer than 10 years. Older age and bulbar onset are consistently reported to have a worse outcome. There are conflicting data on gender, diagnostic delay and El Escorial criteria. The rate of symptom progression was revealed to be an independent prognostic factor. Psychosocial factors, FTD, nutritional status, and respiratory function are also related to ALS outcome. The effect of enteral nutrition on survival is still unclear, while NIPPV has been found to improve survival. There are no well established biological markers of progression, although some are likely to emerge in the near future. These findings have relevant implications for the design of future trials. Randomization, besides the type of onset, should take into account age, respiratory status at entry, and a measure of disease progression pre-entry. Alternative trial designs can include the use of natural history controls, the so-called minimization method for treatment allocation, and the futility approach.

Randomised controlled trial in non-invasive ventilation: what trial?

Amyotrophic lateral sclerosis (ALS) is caused by mutations in the gene for Cu/Zn superoxide dismutase (SOD1) in 10% of familial and sporadic cases. During the SOD1 analysis of 9 FALS and 121 SALS, in only one sporadic case we found the exonic mutation N19S; in 15 SALS patients we found a 319t>a variation in IVS1 sequence, at 108 bp upstream from exon 2. This variation has an unusually high frequency of 11% and is always in linkage disequilibrium with a described polymorphism in IVS3, +34a>c. The 319t>a variation is classified in two different public databases, HGMD and The ALS Online Database, as a splicing mutation and not as a polymorphism. The unusually high frequency of this mutation in our patients prompted us to determinate its frequency in 130 age- and gender- matched healthy controls and in 54 patients with Alzheimer's disease. We found again linkage disequilibrium with the polymorphism in intron 3, and the frequency of 11% and 7.8%, respectively. These results strongly support the idea that the IVS1 +319 t>a alone is not an ALS causing mutation, and that special care must be taken in the interpretation of data from mutations databases for correct genetic counselling.

Sleep characteristics of amyotrophic lateral sclerosis in patients with preserved diaphragmatic function

There are a number of sleep studies in amyotrophic lateral sclerosis (ALS), in general including a heterogeneous population of patients. We aimed to study sleep in a population of selected ALS patients by investigating nocturnal polysomnography (PSG) characteristics in ALS patients with normal respiratory function tests and preserved diaphragmatic innervation. Ninety-two ALS patients were screened by percutaneous nocturnal oximetry (PNO). Eleven ALS patients with normal respiratory function tests, phrenic motor responses and preserved motor units on needle electromyography of the diaphragm, but abnormal PNO, were selected for PSG. REM was present in eight patients, but normal in only three. Three patients had mixed apnoea-hypopnoea, severe in one. Seven showed a pattern of periodic mild O(2) desaturation, which occurred in REM 3, REM and NREM 3 and in NREM sleep 1. One patient studied six months later had more severe changes in the second evaluation. In conclusion, the most common sleep disordered breathing was periodic mild O(2) desaturation independent of the sleep stage (REM, NREM). This might represent central drive dysfunction or respiratory muscle fatigue in ALS.

Evaluation of sham non‐invasive ventilation for randomized, controlled trials in ALS

Non-invasive positive pressure ventilation (NIV) treatment of advanced respiratory insufficiency prolongs survival in ALS. To investigate the critical question of whether earlier initiation of NIV might provide additional benefit, a randomized trial with an appropriate placebo is needed. This study evaluated sub-therapeutic (sham) continuous positive airway pressure as a potential placebo. In a single-blind design, 40 ALS patients with forced vital capacity>50% were randomized to receive 30 seconds (s) of either active NIV, with 8 cm H2O inspiratory and 4 cm H2O expiratory pressure, or sham NIV with<1 cm of H2O continuous positive airway pressure at the mask. A questionnaire was then used to assess whether subjects thought that they had received a "real" or "pretend" treatment trial. The subjects' median age was 60.5 years, and 38% were female. Twelve of 20 subjects (60%) who received active NIV and 7 (35%) of the 20 subjects who received sham thought that they had tried the active treatment (p = 0.11). Only 8 (20%) of all subjects were confident about their determination that they had received "real" or "pretend" NIV. Thus, sub-therapeutic (sham) continuous positive airway pressure is a promising placebo control for NIV trials in ALS.

Evidence for central abnormality in respiratory control in primary lateral sclerosis

Primary lateral sclerosis (PLS) is a very rare disease characterized by pure upper motor neuron findings. Although a number of previous reports have evaluated this condition, no study has addressed the respiratory function in PLS. Six patients meeting previously proposed diagnostic criteria for PLS were submitted to a number of respiratory tests: forced vital capacity, maximal pressures, phrenic nerve responses, needle electromyography of the respiratory muscles, percutaneous nocturnal oximetry (PNO) and polysomnography (two patients). Our results show that the diaphragm is not affected in this condition, but some respiratory function tests (RFT) and PNO had abnormal values. Voluntary muscular activation to perform RFT may be limited in these patients. PNO and polysomnography suggest that respiratory central drive dysfunction can occur when upper motor neurons are severely affected, in PLS. However, we did not verify progression on follow-up.

Clinical care of patients with amyotrophic lateral sclerosis

Although amyotrophic lateral sclerosis and its variants are readily recognised by neurologists, about 10% of patients are misdiagnosed, and delays in diagnosis are common. Prompt diagnosis, sensitive communication of the diagnosis, the involvement of the patient and their family, and a positive care plan are prerequisites for good clinical management. A multidisciplinary, palliative approach can prolong survival and maintain quality of life. Treatment with riluzole improves survival but has a marginal effect on the rate of functional deterioration, whereas non-invasive ventilation prolongs survival and improves or maintains quality of life. In this Review, we discuss the diagnosis, management, and how to cope with impaired function and end of life on the basis of our experience, the opinions of experts, existing guidelines, and clinical trials. We highlight the need for research on the effectiveness of gastrostomy, access to non-invasive ventilation and palliative care, communication between the care team, the patient and his or her family, and recognition of the clinical and social effects of cognitive impairment. We recommend that the plethora of evidence-based guidelines should be compiled into an internationally agreed guideline of best practice.

When should home mechanical ventilation be started in patients with different neuromuscular disorders?

BACKGROUND AND OBJECTIVES

Current international consensus guidelines identify a number of indicators for the establishment of home mechanical ventilation (HMV) for patients with neuromuscular diseases but do not address the possible clinical differences between each of the underlying disorders. This study assessed the differences in the physiological parameters of patients with neuromuscular disease commenced on HMV for the treatment of symptomatic chronic hypercapnic respiratory failure.

METHODS

Patients commenced on HMV for the treatment of symptomatic chronic hypercapnic respiratory failure over a 9-year period were studied. Physiological parameters at the time of referral for HMV, impact of HMV and survival were analysed.

RESULTS

The study recruited 66 patients with neuromuscular disease. Thirty-one patients had rapidly progressive disease: amyotrophic lateral sclerosis (ALS, n = 19), Duchenne muscular dystrophy (DMD, n = 12) and 35 patients had slowly progressive disease. Mean FVC at HMV onset was 40.3 +/- 17.5% predicted in all patients, but was >50% predicted in eight patients (12%). ALS patients were more hypercapnic (P = 0.03) and more hypoxaemic (P < 0.001), but had better FEV(1) at HMV onset, compared with DMD patients (P = 0.005). Maximal inspiratory mouth occlusion pressure (PImax) was 3.0 +/- 1.6 kPa in all patients, but values were lower compared with international consensus guidelines (5.88 kPa). Median survival in DMD, slowly progressive diseases and ALS was 132, 82 and 16 months, respectively (P < 0.001).

CONCLUSIONS

Blood gases and lung function parameters vary substantially between patients with differing underlying neuromuscular disorders when commenced on HMV for the treatment of symptomatic chronic hypercapnic respiratory failure. In contrast, PImax is equally reduced in all patients and more severely reduced compared with consensus guidelines. The specific underlying neuromuscular disease has a major impact on outcome. Specific selection criteria are needed for the use of HMV in the different diseases that comprise neuromuscular disorders.

Early use of non-invasive ventilation prolongs survival in subjects with ALS

Non-invasive positive pressure ventilation (NPPV) can improve survival in ALS patients with advanced respiratory impairment, but it is not known if it is beneficial earlier in the disease course. A retrospective cohort study of patients with ALS was performed comparing survival from time of diagnosis in subjects who started NPPV use when their FVC was >or=65% predicted (Early NPPV) with subjects who started NPPV when their FVC was below 65% predicted (Standard NPPV). The Early group (n = 25) and the Standard group (n = 67) were similar except for pulmonary function (mean FVC in Early NPPV group = 74.3+/-10.1% predicted and 48.3+/-11.3 in Standard group, p<0.001). The median time from ALS diagnosis to death was significantly longer in the Early NPPV group (2.7 years vs. 1.8 years, p = 0.045). This remained significant after adjustment for potential confounding factors (H.R. = 0.55, 95% CI 0.31-0.98). Survival from time of diagnosis was nearly one year longer in the Early group. Until more definitive data are available from randomized trials, our findings suggest that clinicians either encourage earlier use of NPPV or use more sensitive tests for respiratory muscle impairment than upright FVC.

A population based study of respiratory function in motor neuron disease patients living in Tayside and North East Fife, Scotland

Respiratory failure is a major cause of morbidity and the principal cause of death in motor neuron disease; non-invasive ventilation is increasingly used worldwide to palliate the respiratory symptoms. This observational study was designed to evaluate the prevalence of respiratory insufficiency within the motor neuron disease population of Tayside and North East Fife, Scotland. Twenty-six patients were identified, their diagnosis confirmed according to agreed criteria and subjected to the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, the Epworth Sleepiness questionnaire; spirometry, sniff nasal inspiratory pressure and nocturnal pulse oximetry measurements.Twenty-two (84.6%) patients reported one or more symptoms of respiratory insufficiency, 19 patients (73%) had forced vital capacity <80% of predicted in the sitting position and 10 (38.5%) had oxygen saturation <90% for >5% of night. On this basis a potential 10 patients required consideration for ventilation. As well as probable improvement in quality of life and survival for those patients this potential increase in workload has major educational, management and resource implications for health care providers.

A retrospective analysis of sleep quality and survival with domiciliary ventilatory support in motor neuron disease

Previous studies have demonstrated that domiciliary ventilatory support improves survival, quality of life and cognitive function in motor neuron disease (MND). These benefits are partly attributed to better sleep quality and less hypoxia. In a retrospective analysis we compared the effect of non-invasive (NPPV, n = 52), tracheostomy (TPPV, n = 23) and no ventilation (n = 43) on sleep and survival in MND patients over a seven-year period. The TPPV and NPPV groups had more sleep arousals (AI, p = 0.024), more respiratory events (p = 0.001) and more time asleep with an oxygen saturation less than 90% (%TST with SpO2<90%, p = 0.01), than those who were not ventilated. After treatment with TPPV or NPPV, the percentage of rapid eye movement sleep increased (p<0.001) and the %TST with Sp02<90% (p = 0.006) and AI (p = 0.001) decreased. Improvements were larger and more consistent with NPPV. The median survival of those who used TPPV was 41 months, NPPV 32 months and of those not ventilated was 25 months, significantly different four years (p = 0.0497) after symptom onset. In this retrospective cohort of MND patients, ventilation, particularly NPPV, markedly improved sleep and conferred a modest survival advantage.

Management of respiration in MND/ALS patients: an evidence based review

This systematic review comprises an objective appraisal of the evidence in regard to the management of respiration in patients with motor neuron disease (MND/ALS). Studies were identified through computerised searches of 32 databases. Internet searches of websites of drug companies and MND/ALS research web sites, 'snow balling' and hand searches were also employed to locate any unpublished study or other 'grey literature' on respiration and MND/ALS. Since management of MND/ALS involves a number of health professionals and care workers, searches were made across multiple disciplines. No time frame was imposed on the search in order to increase the probability of identifying all relevant studies, although there was a final limit of March 2005. Recommendations for patient and carer-based guidelines for the clinical management of respiration for MND/ALS patients are suggested on the basis of qualitative analyses of the available evidence. However, these recommendations are based on current evidence of best practice, which largely comprises observational research and clinical opinion. There is a clear need for further evidence, in particular randomised and non-randomised controlled trials on the effects of non-invasive ventilation and additional larger scale cohort studies on the issues of initial assessment of respiratory symptoms, and management and timing of interventions.

Maladies neuromusculaires : évaluation des fonctions ventilatoires

Involvement of respiratory muscles is a nearly constant feature of neuromuscular disorders, leading to respiratory failure. A careful respiratory follow up adapted to the variable time course of each disease is therefore mandatory. As the first step, a systematic clinical evaluation is essential to detect the subtle respiratory symptoms and signs related to respiratory muscle failure. Dyspnea and orthopnea are often late findings in patients with a usually severe functional impairment due to peripheral muscle weakness. Nocturnal respiratory events (obstructive sleep apnea syndrome and hypoventilation) are strongly suggested by daytime hypersomnolence and frequent morning headaches. Physical evaluation is essential to detect accessory muscle recruitment, supine abdominal paradox, and encumbrance of upper or lower airways. Vital capacity (VC) is the most classical lung function test. The major limitation of spirometry is its poor sensitivity to detect a moderate inspiratory muscle weakness. Supine VC may improve the detection of diaphragmatic involvement. Peak expiratory flow during cough (cough PEF) gives an overall evaluation of cough efficiency, values below 160 to 270 L/min suggesting poor airway clearance. Arterial blood gases are performed in case of clinical signs, significant deterioration of lung function tests, or sleep desaturations. Hypercapnia is weakly related to lung function results in patients with Steinert dystrophy and those with bulbar involvement. A specific evaluation of respiratory muscle strength is mandatory, as these tests are both sensitive and highly prognostic. Possible discrepancies (particularly in bulbar patients) between maximal inspiratory pressure (PImax) and sniff nasal inspiratory pressure (SNIP) justify to perform both measurements and to select the highest pressure. A maximal expiratory pressure (PEmax) below 45 cm H2O may indicate a compromised cough efficiency but the correlation with cough PEF may be poor. A screening nocturnal oxymetry is useful to detect sleep apneas and hypoventilation. Criteria defining significant desaturations remain however controversial. Suspicion of obstructive sleep apnea syndrome on clinical grounds or oxymetry findings should be confirmed by a conventional polysomnography.

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.

Survival in Amyotrophic Lateral Sclerosis With Home Mechanical Ventilation

STUDY OBJECTIVES

To analyze (1) the impact of a protocol of early respiratory evaluation of the indications for home mechanical ventilation (HMV) in patients with amyotrophic lateral sclerosis (ALS), and (2) the effects of the protocol and of bulbar involvement on the survival of patients receiving noninvasive ventilation (NIV).

DESIGN AND SETTING

Retrospective study in a tertiary care referral center.

PATIENTS

HMV was indicated in 86 patients with ALS, with 22 patients (25%) presenting with intolerance to treatment associated with bulbar involvement. Treatment with HMV had been initiated in 15 of 64 patients prior to initiating the protocol (group A) and in the remaining 49 patients after protocol initiation (group B).

RESULTS

In group A, the majority of patients began treatment with HMV during an acute episode requiring ICU admission (p = 0.001) and tracheal ventilation (p = 0.025), with a lower percentage of patients beginning HMV treatment without respiratory insufficiency (p = 0.013). No significant differences in survival rates were found between groups A and B among patients treated with NIV. Greater survival was observed in group B (p = 0.03) when patients with bulbar involvement were excluded (96%). Patients without bulbar involvement at the start of therapy with NIV presented a significantly better survival rate (p = 0.03). Multivariate analysis showed bulbar involvement to be an independent prognostic factor for survival (relative risk, 1.6; 95% confidence interval, 1.01 to 2.54; p = 0.04). No significant differences in survival were observed between patients with bulbar involvement following treatment with NIV and those with intolerance, except for the subgroup of patients who began NIV treatment with hypercapnia (p = 0.0002).

CONCLUSIONS

Early systematic respiratory evaluation in patients with ALS is necessary to improve the results of HMV. Further studies are required to confirm the benefits of NIV treatment in patients with bulbar involvement, especially in the early stages.