Respiratory assistance with a non-invasive ventilator (Bipap) in MND/ALS patients: survival rates in a controlled trial

Clinical review: long-term noninvasive ventilation

Noninvasive positive ventilation has undergone a remarkable evolution over the past decades and is assuming an important role in the management of both acute and chronic respiratory failure. Long-term ventilatory support should be considered a standard of care to treat selected patients following an intensive care unit (ICU) stay. In this setting, appropriate use of noninvasive ventilation can be expected to improve patient outcomes, reduce ICU admission, enhance patient comfort, and increase the efficiency of health care resource utilization. Current literature indicates that noninvasive ventilation improves and stabilizes the clinical course of many patients with chronic ventilatory failure. Noninvasive ventilation also permits long-term mechanical ventilation to be an acceptable option for patients who otherwise would not have been treated if tracheostomy were the only alternative. Nevertheless, these results appear to be better in patients with neuromuscular/-parietal disorders than in chronic obstructive pulmonary disease. This clinical review will address the use of noninvasive ventilation (not including continuous positive airway pressure) mainly in diseases responsible for chronic hypoventilation (that is, restrictive disorders, including neuromuscular disease and lung disease) and incidentally in others such as obstructive sleep apnea or problems of central drive.

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.

Nocturnal mechanical ventilation for chronic hypoventilation in patients with neuromuscular and chest wall disorders

BACKGROUND

Chronic alveolar hypoventilation is a common complication of many neuromuscular and chest wall disorders. Long-term nocturnal mechanical ventilation is increasingly used to treat it.

OBJECTIVES

To examine the efficacy of nocturnal mechanical ventilation in relieving hypoventilation related symptoms and in prolonging survival in people with neuromuscular or chest wall disorders.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register, MEDLINE (from January 1966 to June 2006), and EMBASE (from January 1980 to June 2006) for randomised trials and contacted authors of trials and other experts in the field.

SELECTION CRITERIA

We searched for quasi-randomised or randomised controlled trials of participants with neuromuscular or chest wall disorder-related stable chronic hypoventilation of all ages and all degrees of severity, receiving any type and any mode of nocturnal mechanical ventilation. The primary outcome measure was short-term and long-term reversal of hypoventilation related clinical symptoms and secondary outcomes were unplanned hospital admission, one year mortality, short-term and long-term reversal of daytime hypercapnia, improvement of lung function and sleep breathing disorders.

DATA COLLECTION AND ANALYSIS

We identified eight randomised trials.

MAIN RESULTS

The eight eligible trials included a total of 144 participants. The relative risk of 'no improvement of hypoventilation related clinical symptoms' in the short-term following nocturnal mechanical ventilation was available in only one trial with 10 participants and was not significant, 0.09 (95% confidence interval (CI) 0.01 to 1.31). The relative risk of 'no reversal of daytime hypercapnia' in the short-term following nocturnal ventilation was significant and favoured treatment, 0.37 (95% CI 0.20 to 0.65). The weighted mean difference of nocturnal mean oxygen saturation was 5.45% (95% CI 1.47 to 9.44) more improvement in participants treated with nocturnal mechanical ventilation. For most of the outcome measures there was no significant long-term difference between nocturnal mechanical ventilation and no ventilation. However, the estimated risk of death based on three studies was reduced following nocturnal ventilation, 0.62 (95% CI 0.42 to 0.91). There was considerable and significant heterogeneity between the trials possibly related to differences between the study populations. Most of the secondary outcomes were not assessed in the eligible trials. Data from two crossover trials suggested no evidence for a difference in reversal of daytime hypercapnia and sleep study parameters between volume-cycled and pressure-cycled ventilation. No data could be summarised for the comparisons between invasive and non-invasive mechanical ventilation or between intermittent positive pressure and negative pressure ventilation.

AUTHORS' CONCLUSIONS

Current evidence about the therapeutic benefit of mechanical ventilation is weak, but consistent, suggesting alleviation of the symptoms of chronic hypoventilation in the short-term. In three small studies survival was prolonged mainly in participants with motor neuron diseases. With the exception of motor neuron disease, further larger randomised trials are needed to confirm long-term beneficial effects of nocturnal mechanical ventilation on quality of life, morbidity and mortality, to assess its cost-benefit ratio in neuromuscular and chest wall diseases and to compare the different types and modes of ventilation.

Respiratory apraxia in amyotrophic lateral sclerosis

Respiratory dysfunction is a critical problem in amyotrophic lateral sclerosis (ALS). We report a patient with ALS who had respiratory apraxia. A 74-year-old female presented with progressive dysarthria and dysphagia. Clinical signs and evidence of widespread denervation on electromyography (EMG) confirmed the diagnosis of ALS. She had no signs of dementia. Irregular volitional inspiratory movements on verbal command were noticed, in contrast with rhythmic automatic inspiration - respiratory apraxia. Limb and buco-facial movements showed no signs of apraxia. EMG of respiratory muscles was normal, apart from irregular phasic activity of the diaphragm on volitional inspiration; this was confirmed by recording respiratory movements with a percutaneous sensor transducer. Sleep study was normal. She deteriorated rapidly; nonetheless, no clinical sign of dementia or other apraxic findings were observed. ALS, particularly when of bulbar onset, can cause respiratory apraxia and EMG of the respiratory muscles can be useful to detect this condition.

Non-invasive positive ventilation in the treatment of sleep-related breathing disorders

This chapter addresses the use of long-term non-invasive positive pressure ventilation (NIPPV) (to the exclusion of continuous positive airway pressure) in the different clinical settings in which it is currently proposed: principally in diseases responsible for hypoventilation characterized by elevated PaCO(2). Nasal masks are predominantly used, followed by nasal pillow and facial masks. Mouthpieces are essentially indicated in case daytime ventilation is needed. Many clinicians currently prefer pressure-preset ventilator in assist mode as the first choice for the majority of the patients with the view of offering better synchronization. Nevertheless, assist-control mode with volume-preset ventilator is also efficient. The settings of the ventilator must insure adequate ventilation assessed by continuous nocturnal records of at least oxygen saturation of haemoglobin-measured by pulse oximetry. The main categories of relevant diseases include different types of neuromuscular disorders, chest-wall deformities and even lung diseases. Depending on the underlying diseases and on individual cases, two schematic situations may be individualized. Either intermittent positive pressure ventilation (IPPV) is continuously mandatory to avoid death in the case of complete or quasi-complete paralysis or is used every day for several hours, typically during sleep, producing enough improvement to allow free time during the daylight in spontaneous breathing while hypoventilation and related symptoms are improved. In case of complete or quasi-complete need of mechanical assistance, a tracheostomy may become an alternative to non-invasive access. In neuromuscular diseases, in kyphosis and in sequela of tuberculosis patients, NIPPV always significantly increases survival. Conversely, no data support a positive effect on survival in chronic obstructive pulmonary disease.

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.

Longitudinal assessment of noninvasive positive pressure ventilation adjustments in ALS patients

The absence of data guiding optimal titration of noninvasive positive pressure ventilation (NIPPV) over time in ALS patients may contribute to the under-prescribing of NIPPV. We conducted a retrospective, single-center, chart review assessment of NIPPV pressure settings used for symptomatic treatment of ALS patients to determine NIPPV adjustments, and to compare survival between those who were tolerant and intolerant to NIPPV. All subjects were started on nocturnal NIPPV at 8 and 3 cm H2O inspiratory and expiratory pressure, respectively. Of the 18 tolerant subjects identified, 4 (22%) had no NIPPV pressure changes before death; 8 (44%), 1 change; 4 (22%), 2 changes; 1 (6%), 3 changes; and 1 (6%), 5 changes. Most pressure changes occurred during the first year of NIPPV initiation. The maximum pressure needed for comfort by any patient in this study was 19/5 cm H2O, while 4 (22%) found the original 8/3 cm H2O settings to be sufficient until death. Subjects in the tolerant group had better survival, when adjusting for age and site of symptom onset (bulbar versus limb), with a hazard ratio of 0.23 [95% confidence interval: 0.10, 0.54]. The current data suggest that ALS patients who are tolerant to NIPPV typically need at least one upward change in pressure settings. Tolerance to relatively low NIPPV inspiratory pressures is associated with improved survival.

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.

Supramaximal Inflation Improves Lung Compliance in Subjects With Amyotrophic Lateral Sclerosis

RATIONALE

Lung compliance has been found to be low in patients with chronic diaphragmatic weakness or paralysis but has not been well-studied in patients with amyotrophic lateral sclerosis (ALS). Noninvasive positive-pressure ventilation (NPPV) prolongs survival in ALS patients but may also have additional beneficial effects.

OBJECTIVES

This study evaluated static expiratory lung compliance (CL) in subjects with ALS and determined the effect of lung inflation with supramaximal inflation on CL.

DESIGN

This was a prospective trial comparing CL before and after supramaximal lung inflation via mouthpiece-delivered positive pressure.

SETTING

A single university medical center with an multidisciplinary ALS center.

PARTICIPANTS

Fourteen subjects with ALS were compared to 4 healthy volunteers.

INTERVENTIONS

Subjects underwent a battery of pulmonary function tests including for CL. Then they used positive pressure administered via a mouthpiece set to 10 cm H2O above their maximal static recoil pressure for 5 min. The CL measurement was then repeated.

RESULTS

The mean (+/- SD) baseline CL was reduced (164.1 +/- 82.1 mL/cm H2O) in subjects with ALS and was significantly lower than that in healthy volunteers (237.5 mL/cm H2O; p = 0.04). CL increased significantly in subjects with evidence of diaphragm weakness (change in CL, 11.3 +/- 16.7 mL/cm H2O; p = 0.03). Healthy volunteers did not have an increase in CL.

CONCLUSIONS

Patients with ALS and diaphragmatic weakness have reduced CL, and brief supramaximal inflation increases CL. These findings suggest that atelectasis or increased alveolar surface forces are present in ALS patients and that these patients will have increased work of breathing. Some of the beneficial effects demonstrated with NPPV therapy may be through its effects on CL and the work of breathing.

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.

Effects of non-invasive ventilation on survival and quality of life in patients with amyotrophic lateral sclerosis: a randomised controlled trial

BACKGROUND

Few patients with amyotrophic lateral sclerosis currently receive non-invasive ventilation (NIV), reflecting clinical uncertainty about the role of this intervention. We aimed to assess the effect of NIV on quality of life and survival in amyotrophic lateral sclerosis in a randomised controlled trial.

METHODS

92 of 102 eligible patients participated. They were assessed every 2 months and randomly assigned to NIV (n=22) or standard care (n=19) when they developed either orthopnoea with maximum inspiratory pressure less than 60% of that predicted or symptomatic hypercapnia. Primary validated quality-of-life outcome measures were the short form 36 mental component summary (MCS) and the sleep apnoea quality-of-life index symptoms domain (sym). Both time maintained above 75% of baseline (T(i)MCS and T(i)sym) and mean improvement (microMCS and microsym) were measured.

FINDINGS

NIV improved T(i)MCS, T(i)sym, microMCS, microsym, and survival in all patients and in the subgroup with better bulbar function (n=20). This subgroup showed improvement in several measures of quality of life and a median survival benefit of 205 days (p=0.006) with maintained quality of life for most of this period. NIV improved some quality-of-life indices in those with poor bulbar function, including microsym (p=0.018), but conferred no survival benefit.

INTERPRETATION

In patients with amyotrophic lateral sclerosis without severe bulbar dysfunction, NIV improves survival with maintenance of, and improvement in, quality of life. The survival benefit from NIV in this group is much greater than that from currently available neuroprotective therapy. In patients with severe bulbar impairment, NIV improves sleep-related symptoms, but is unlikely to confer a large survival advantage.

Paradoxical response of VEGF expression to hypoxia in CSF of patients with ALS

Vascular endothelial growth factor (VEGF) is implicated in motor neurone degeneration. In normal individuals, hypoxia is known to induce an overexpression of VEGF, as measured in CSF. We show that patients with ALS do not manifest this VEGF overexpression in the presence of hypoxia. Although VEGF gene expression is mainly stimulated by hypoxia, we have measured lower VEGF levels in cerebrospinal fluid (CSF) from hypoxaemic patients with amyotrophic lateral sclerosis (ALS) than in CSF from normoxaemic patients with ALS. In contrast, hypoxaemic neurological controls displayed higher levels than normoxaemic neurological controls. There was a negative correlation between VEGF levels and the severity of hypoxaemia in patients with ALS, suggesting deregulation of VEGF in ALS.

Clinical trials in ALS: a review of the role of clinical and neurophysiological measurements

We have reviewed all the published clinical trials of ALS and, from those considered sufficiently large, and containing a control group, we have evaluated their methodology with regard to statistical power. This implies a critical analysis of the endpoint measurements. We have concluded that clinical endpoints used in clinical trials of ALS have frequently been insufficiently sensitive, non-linear, or even not intuitively highly relevant to the disease. We suggest that the ALS-FRS, perhaps also MUNE and the Neurophysiological Index, may be the best measures currently available. These techniques have complementary characteristics that allow them to be used to address different aspects of the disease and its treatment in various trials designs. In the past some trials may have failed to demonstrate a treatment effect because the chosen endpoint measures and the trial design were inappropriate.

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.

Randomised controlled trial of non-invasive ventilation (NIV) for nocturnal hypoventilation in neuromuscular and chest wall disease patients with daytime normocapnia

BACKGROUND

Long term non-invasive ventilation (NIV) reduces morbidity and mortality in patients with neuromuscular and chest wall disease with hypercapnic ventilatory failure, but preventive use has not produced benefit in normocapnic patients with Duchenne muscular dystrophy. Individuals with nocturnal hypercapnia but daytime normocapnia were randomised to a control group or nocturnal NIV to examine whether nocturnal hypoventilation is a valid indication for NIV.

METHODS

Forty eight patients with congenital neuromuscular or chest wall disease aged 7-51 years and vital capacity<50% predicted underwent overnight respiratory monitoring. Twenty six with daytime normocapnia and nocturnal hypercapnia were randomised to either nocturnal NIV or to a control group without ventilatory support. NIV was started in the control group if patients fulfilled preset safety criteria.

RESULTS

Peak nocturnal transcutaneous carbon dioxide tension (Tcco2) did not differ between the groups, but the mean (SD) percentage of the night during which Tcco2 was >6.5 kPa decreased in the NIV group (-57.7 (26.1)%) but not in controls (-11.75 (46.1)%; p=0.049, 95% CI -91.5 to -0.35). Mean (SD) arterial oxygen saturation increased in the NIV group (+2.97 (2.57)%) but not in controls (-1.12 (2.02)%; p=0.024, 95% CI 0.69 to 7.5). Nine of the 10 controls failed non-intervention by fulfilling criteria to initiate NIV after a mean (SD) of 8.3 (7.3) months.

CONCLUSION

Patients with neuromuscular disease with nocturnal hypoventilation are likely to deteriorate with the development of daytime hypercapnia and/or progressive symptoms within 2 years and may benefit from the introduction of nocturnal NIV before daytime hypercapnia ensues.

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.

Surveillance et traitement des troubles respiratoires associés à la sclérose latérale amyotrophique

INTRODUCTION

In amyotrophic lateral sclerosis (ALS), respiratory muscle involvement is highly predictive of survival and quality of life (QOL). There is compelling evidence that non invasive ventilation (NIV) prolongs survival by several months and improves QOL more than any other currently available treatment. Frequent testing of pulmonary function and regular evaluations are recommended since 1999 by the American Academy of Neurology in order to take appropriate treatment decisions.

STATE OF ART

There are numerous tests available to evaluate respiratory status in ALS and it is important to know their sensitivity and specificity to recognize clinical risk situations. Some recent data suggest that sniff nasal pressure and maximal inspiratory pressure (MIP) can be performed reliably by most ALS patients and are more sensitive to decrements in inspiratory muscle strength than spirometry or arterial blood gasometry.

PERSPECTIVES

Airway obstruction caused by ineffective coughing is the principal cause of intolerance to NIV. Several factors other than respiratory muscle strength may affect pulmonary function: postural changes, nutritional status, infectious disease, drugs.

CONCLUSION

The neurologist has to coordinate multidisciplinary care, with attention to individual patient preferences, and with a frank and compassionate discussion between the patient, the family, the physicians and the caregivers.

Descriptive epidemiology of amyotrophic lateral sclerosis in Japan, 1995-2001

BACKGROUND: This study was conducted to describe the epidemiologic features of amyotrophic lateral sclerosis (ALS) in Japan by examining annual trends in mortality (1995-2001), and to discuss the background factors possibly responsible for the recent variations in the mortality rate.

METHODS: Trends in both the age-adjusted and age-specific mortality rates of ALS were examined by using the data obtained from the vital statistics of Japan between 1995 and 2001.

RESULTS: There were small increases in the number of ALS deaths (from 1249 to 1400 per year) and the crude mortality rates (from 1.00 to 1.10 per 100,000 population) between 1995 and 2001. The age-adjusted mortality rate of ALS (adjusted using the 1985 model population of Japan) has decreased (from 0.84 per 100,000 population in 1995 to 0.74 in 2001). Age-specific mortality rates have been increasing particularly in the population older than 70 years of age, with the peak in mortality in the 70- to 80-year old age group.

CONCLUSIONS: ALS mortality rates increased proportionally more for elderly population during the study period. Further epidemiologic studies will be needed to clarify the possible background factors contributing to the increase in ALS mortality in the elderly.

Use of Sniff Nasal-Inspiratory Force to Predict Survival in Amyotrophic Lateral Sclerosis

Respiratory muscle weakness is the usual cause of death in amyotrophic lateral sclerosis. The prognostic value of the forced vital capacity (FVC), mouth-inspiratory force, and sniff nasal-inspiratory force were established in a group of 98 patients with amyotrophic lateral sclerosis who were followed trimonthly for 3 years. Sniff nasal-inspiratory force correlated with the transdiaphragmatic pressure (r = 0.9, p < 0.01). Sniff nasal-inspiratory force was most likely to be recorded at the last visit (96% of cases), compared with either the FVC or mouth-inspiratory force (86% and 81%, respectively, p < 0.01). A sniff nasal-inspiratory force less than 40 cm H(2)O was significantly related with nocturnal hypoxemia. When sniff nasal-inspiratory force was less than 40 cm H(2)O, the hazard ratio for death was 9.1 (p = 0.001), and the median survival was 6 +/- 0.3 months. The sensitivity of FVC < 50% for predicting 6-month mortality was 58% with a specificity of 96%, whereas sniff nasal-inspiratory force less than 40 H(2)O had a sensitivity of 97% and a specificity of 79% for death within 6 months. Thus the sniff nasal-inspiratory force test is a good measure of respiratory muscle strength in amyotrophic lateral sclerosis, it can be performed by patients with advanced disease, and it gives prognostic information.

Oximetry and indications for tracheotomy for amyotrophic lateral sclerosis

STUDY OBJECTIVE

To explore the use of oximetry as a guide for using respiratory aids and tracheotomy in the treatment of patients with amyotrophic lateral sclerosis (ALS).

SETTING

A retrospective review of all ALS patients presenting to a neuromuscular disease clinic since 1996.

METHODS

Patients who were symptomatic for nocturnal hypoventilation were prescribed noninvasive ventilation (NIV). Patients with assisted cough peak flows of < 300 L/min were prescribed oximeters and access to mechanically assisted coughing (MAC) to prevent or reverse decreases in baseline pulse oximetric saturation (Spo(2)) levels of < 95%. The number of decreases in baseline Spo(2) that could be normalized by any combination of NIV and MAC and the duration of normalization were recorded. When the baseline was not or could not be normalized, the time to acute respiratory failure and tracheotomy or death were recorded.

RESULTS

Twenty-five patients became dependent on NIV, including 13 patients who received NIV continuously for a mean (+/- SD) period of 19.7 +/- 16.9 months, without desaturation (group 1). For another 76 patients, the daytime baseline Spo(2) level decreased to < 95% 78 times. For 41 patients, the baseline level was corrected by NIV/MAC (group 2) for a mean duration of 11.1 +/- 8.7 months before desaturation reoccurred for 27 patients. Of the latter patients, 11 underwent tracheotomy, 14 died in < 2 months, and 2 had their condition again corrected by the addition of MAC therapy. For 35 patients, the desaturation was not or could not be normalized (group 3). Thirty-three of these 35 patients required tracheotomy or died within 2 months. The only significant difference between groups 1 and 2 and group 3 was significantly poorer glottic function in the patients in group 3.

CONCLUSION

Tracheotomy or death is highly likely within 2 months of a decrease in baseline Spo(2) that cannot be corrected by NIV or MAC. The long-term use of NIV and MAC, and the avoidance of tracheotomy is dependent on glottic function rather than on inspiratory or expiratory muscle failure.

Insuficiência respiratória aguda como primeira manifestação de esclerose lateral amiotrófica: dois casos clínicos

Amyotrophic Lateral Sclerosis (ALS) is a fast progressing neuromuscular disease that affects all but the extrinsic muscles of the eye and sphincters. The main cause of morbidity and mortality are the respiratory complications that usually start in a late stage of the diseases natural history. In a small number of cases acute respiratory failure is the initial manifestation of the disease. The authors present 2 case studies admitted to a pulmonary department, without previously known neuromuscular disease, with the diagnosis of acute respiratory failure of unknown etiology and that were later shown to be cases of ALS. Analysis of the cases presented here, and those already published in the literature, suggests that the occurrence of acute respiratory failure in patients without a previous history of pulmonary and/or heart disease, especially in the 5th and 6th decade of life, should alert to ALS as a possible diagnosis.

Longitudinal effects of noninvasive positive-pressure ventilation in patients with amyotrophic lateral sclerosis

OBJECTIVE

To evaluate the duration of benefit on symptoms, quality of life, and survival derived from the use of noninvasive positive-pressure ventilation by patients with amyotrophic lateral sclerosis.

DESIGN

In this prospective, cohort study, 30 of 36 consecutively referred symptomatic patients tolerated nightly noninvasive positive-pressure ventilation and undertook pulmonary function testing and 12 symptom and quality-of-life instruments concerning sleep quality, daytime sleepiness, physical fatigue, mental fatigue, and depression that were administered during a 10-mo period.

RESULTS

With treatment, there was a significant improvement in the majority of patients in sleep quality, daytime sleepiness, physical fatigue, and depression; however, significant improvements lasted for up to 10 mo only in sleep quality. Partial pressure of arterial oxygen, partial pressure of arterial carbon dioxide, and oxyhemoglobin saturation remained stable or even improved for up to 7 mo during use of part-time noninvasive positive-pressure ventilation. A total of 14 patients had survival prolonged by continuous dependence on noninvasive positive-pressure ventilation.

CONCLUSIONS

Noninvasive positive-pressure ventilation provides a long-lasting benefit on symptoms and quality of life indicators for amyotrophic lateral sclerosis patients and should be offered to all patients with symptoms of sleep disordered breathing or inspiratory muscle dysfunction. It can also prolong tracheostomy-free survival.

Disorders of the respiratory muscles

The act of breathing depends on coordinated activity of the respiratory muscles to generate subatmospheric pressure. This action is compromised by disease states affecting anatomical sites ranging from the cerebral cortex to the alveolar sac. Weakness of the respiratory muscles can dominate the clinical manifestations in the later stages of several primary neurologic and neuromuscular disorders in a manner unique to each disease state. Structural abnormalities of the thoracic cage, such as scoliosis or flail chest, interfere with the action of the respiratory muscles-again in a manner unique to each disease state. The hyperinflation that accompanies diseases of the airways interferes with the ability of the respiratory muscles to generate subatmospheric pressure and it increases the load on the respiratory muscles. Impaired respiratory muscle function is the most severe consequence of several newly described syndromes affecting critically ill patients. Research on the respiratory muscles embraces techniques of molecular biology, integrative physiology, and controlled clinical trials. A detailed understanding of disease states affecting the respiratory muscles is necessary for every physician who practices pulmonary medicine or critical care medicine.

The basic aspects of therapeutics in amyotrophic lateral sclerosis

Once thought to be a single pathological disease state, amyotrophic lateral sclerosis (ALS) is now recognized to be the limited phenotypic expression of a complex, heterogeneous group of biological processes, resulting in an unrelenting loss of motor neurons. On average, individuals affected with the disease live <5 years. In this article, the complex nature of the pathogenesis of ALS, including features of age dependency, environmental associations, and genetics, is reviewed. Once held to be uncommon, it is now clear that ALS is associated with a frontotemporal dementia and that this process may reflect disturbances in the microtubule-associated tau protein metabolism. The motor neuron ultimately succumbs in a state where significant disruptions in neurofilament metabolism, mitochondrial function, and management of oxidative stress exist. The microenvironment of the neuron becomes a complex milieu in which high levels of glutamate provide a source of chronic excitatory neurotoxicity, and the contributions of activated microglial cells lead to further cascades of motor neuron death, perhaps serving to propagate the disease once established. The final process of motor neuron death encompasses many features of apoptosis, but it is clear that this alone cannot account for all features of motor neuron loss and that aspects of a necrosis-apoptosis continuum are at play. Designing pharmacological strategies to mitigate against this process thus becomes an increasingly complex issue, which is reviewed in this article.

Critical care management of neuromuscular disease, including long-term ventilation

PURPOSE OF REVIEW

This review highlights recent advances in the critical care management of neuromuscular disease, particularly in the long-term management of chronic respiratory failure occurring as a consequence of neuromuscular disease.

RECENT FINDINGS

Although randomized clinical trial evidence of benefit is sparse, a large volume of nonrandomized clinical trial evidence has accumulated demonstrating that noninvasive positive pressure ventilation prolongs and improves quality of life in conditions such as Duchenne muscular dystrophy and motor neuron disease.

SUMMARY

Immunomodulatory treatments favorably modify the course of neuromuscular diseases such as Guillain-Barré syndrome, whereas long-term noninvasive positive pressure ventilation has transformed the outlook in previously untreatable conditions such as motor neuron disease and muscular dystrophies. The availability of long-term noninvasive positive pressure ventilation raises major medical, social, economic, and ethical issues that are increasingly being investigated and discussed.

Ethics and decision making in end stage lung disease

Most physicians believe they do more good than harm, and these duties of helping and not harming the patient are rooted in the Hippocratic oath, the good Samaritan tradition, and the Order of the Knight Hospitallers founded in the 11th century to care for pilgrims and those wounded in the Crusades.(1) In recent times the simple principles of beneficence and non-maleficence have been augmented and sometimes challenged by a rising awareness of patient/consumer rights, and the public expectation of greater involvement in medical, social and scientific affairs which affect them. In a publicly funded healthcare system in which rationing (explicit or otherwise) is inevitable, the additional concepts of utility and distributive justice can easily come into conflict with the individual's right to autonomy. Possible treatment options for end stage lung disease include transplantation and long term invasive ventilation which are challenging in resource terms. Other interventions such as pulmonary rehabilitation and palliative care are relatively low cost but not uniformly accessible.

[Noninvasive intermittent self ventilation in chronic respiratory insufficiency]

Corresponding to the two compartments of the respiratory system (lungs and ventilatory pump), two different forms of respiratory insufficiency can be distinguished on a pathophysiologic basis: disturbances of gas exchange with primary oxygenation failure (hypoxemia) due to pulmonary diseases and reduced ventilation of the lungs (hypoventilation) with primary elevated arterial carbon dioxide partial pressure (hypercapnia) and secondary hypoxemia due to disorders of the ventilatory pump. Different methods can be employed in the diagnosis of respiratory insufficiency, e.g., spirometry, blood gas analysis, nocturnal monitoring with capnography, or transcutaneous pCO2 registration and measurement of mouth occluding pressure. Therapeutic measures for respiratory insufficiency are based on two treatment principles: long-term oxygen therapy to improve hypoxemia and noninvasive ventilation therapy to improve hypercapnia and concomitant hypoxemia. The indication for long term ventilation depends on subjective complaints, objective measurement parameters, disease course, and other disease symptoms. The most frequent indications for home mechanical ventilation are diseases with restrictive ventilatory defects, especially chest wall disorders and neuromuscular disorders.

Management of motor neurone disease

Motor neurone disease is a progressive neurodegenerative disorder leading to severe disability and death. It is clinically characterised by mixed upper and lower motor neurone involvement affecting bulbar, limb, and respiratory musculature. Recent guidelines have established diagnostic criteria and defined management of the condition. In a proportion of familial amyotrophic lateral sclerosis there is a mutation in the gene encoding the enzyme copper/zinc superoxide dismutase 1; this has allowed mutation screening and generated considerable laboratory based research. The diagnosis must be given with care and consideration and close follow up is essential. Management involves a multidisciplinary team based in the hospital and the community. Riluzole is the only drug shown to have a disease modifying effect and has been approved by the National Institute for Clinical Excellence. The essence of care is good symptomatic management, including nutritional support with percutaneous endoscopic gastrostomy and ventilatory care with non-invasive ventilation. Palliative care should be introduced before the terminal stages after careful discussion with the patient and carers. Knowledge of this condition has grown dramatically recently with a parallel improvement in treatment and ability to deal with the most troublesome problems.

Amyotrophic lateral sclerosis: prolongation of life by noninvasive respiratory AIDS

STUDY OBJECTIVE

To describe prolongation of survival in patients with amyotrophic lateral sclerosis (ALS) by continuous noninvasive intermittent positive-pressure ventilation (NPPV) and mechanically assisted coughing (MAC) using oximetry as feedback.

SETTING

A retrospective review of ALS patients visiting one center from 1990 to 2000.

DESIGN

Patients were trained in mouthpiece and nasal NPPV when symptomatic for hypoventilation, and trained in MAC with oximetry feedback when assisted peak cough flow (PCF) levels decreased to < 270 L/min. Survival was considered to be prolonged when full-time NPPV was required with limited ventilator-free breathing tolerance.

RESULTS

Of 101 patients who met the criteria for access to NPPV and MAC, 15 have not yet used them, and 11 patients with severe bulbar muscle dysfunction died without ever successfully using them. Three patients used NPPV full-time, and oximetry and MAC episodically, but did not yet require ongoing NPPV. Eighteen used NPPV part-time for a mean (+/- SD) duration of 3.8 +/- 4.1 months. Nineteen others underwent tracheotomy after 4.7 +/- 4.5 months of receiving part-time NPPV. Sixteen patients used part-time NPPV for 17.5 +/- 13.0 months (maximum, 25 months), then full-time NPPV for 14.1 +/- 12.6 months (maximum, 40 months) before undergoing tracheotomy. Nineteen patients used part-time and full-time NPPV for 25.2 +/- 19.8 months (maximum, 114 months) and 17.5 +/- 13.3 months (maximum, 87 months), respectively, without undergoing tracheotomy. Ten of these NPPV users died once bulbar dysfunction became severe.

CONCLUSION

We conclude that up to continuous use of NPPV, along with MAC when needed, can permit prolonged survival and delay the need for tracheotomy for a significant minority of ALS patients by > 1 year.

Outcome of ventilatory support for acute respiratory failure in motor neurone disease

OBJECTIVES

To review the outcome of acute ventilatory support in patients presenting acutely with respiratory failure, either with an established diagnosis of motor neurone disease (MND) or with a clinical event where the diagnosis of MND has not yet been established.

METHODS

Outcome was reviewed in 24 patients with respiratory failure due to MND who received endotracheal intubation and intermittent positive pressure ventilation either at presentation or as a result of the unexpected development of respiratory failure. Patients presenting to local hospitals with acute respiratory insufficiency and requiring tracheal intubation, ventilatory support, and admission to an intensive therapy unit (ITU) before transfer to a regional respiratory care unit were selected. Clinical features of presentation, management, and outcome were studied.

RESULTS

24 patients with MND were identified, all being intubated and ventilated acutely within hours of presentation. 17 patients (71%) were admitted in respiratory failure before the diagnosis of MND had been made; the remaining seven patients (29%) were already known to have MND but deteriorated rapidly such that intubation and ventilation were initiated acutely. Seven patients (29%) died on ITU (between seven and 54 days after admission). 17 patients (71%) were discharged from ITU. 16 patients (67%) received long term respiratory support and one patient required no respiratory support following tracheal extubation. The daily duration of support that was required increased gradually with time.

CONCLUSION

When a patient with MND is ventilated acutely, with or without an established diagnosis, independence from the ventilator is rarely achieved. Almost all of these patients need long term ventilatory support and the degree of respiratory support increases with time as the disease progresses. The aim of management should be weaning the patient to the minimum support compatible with symptomatic relief and comfort. Respiratory failure should be anticipated in patients with MND when the diagnosis has been established.

Primary lateral sclerosis: clinical, neurophysiological, and magnetic resonance findings

OBJECTIVE

To describe the clinical, neurophysiological, and MRI findings in 10 patients with primary lateral sclerosis (PLS).

RESULTS

The course of the disease was very slowly progressive. Spasticity due to upper motor neuron dysfunction was the most prominent sign, but EMG showed slight lower motor neuron signs, such as a mixed pattern on maximal voluntary contraction and enlarged motor unit potentials. One patient had clinically mild lower motor neuron involvement. Central motor conduction times (CMCT) were more prolonged in PLS than is the case in ALS. Minor sensory signs were found on neurophysiological examination, comparable with those in ALS. In four patients serum creatine kinase activity was raised. On MRI cortical atrophy was seen, most pronounced in the precentral gyrus and expanding into the parietal-occipital region.

CONCLUSIONS

PLS is a distinct clinical syndrome, part of the range of motor neuron diseases. Besides pronounced upper motor neuron symptoms, mild lower motor neuron symptoms can also be found, as well as (subclinical) sensory symptoms. PLS can be distinguished from ALS by its slow clinical course, a severely prolonged MEP, and a more extensive focal cortical atrophy.

A preliminary evaluation of a prospective study of pulmonary function studies and symptoms of hypoventilation in ALS/MND patients

There is still no consensus as to which physiologic marker should be used as a trigger for the initiation of non-invasive positive pressure ventilation (NPPV) in patients with amyotrophic lateral sclerosis (ALS). Current practice parameters recommend that the decision to begin treatment be based upon forced vital capacity (FVC) measurements. A prospective, randomized study was performed in 20 ALS patients who had an FVC of 70-100%. Patients received baseline assessments including: ALS functional rating scale-respiratory version (ALSFRS-R), pulmonary symptom scale, Short form 36 (SF-36), FVC%, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and nocturnal oximetry. Patients were randomized to receive NPPV based upon nocturnal oximetry studies suggesting oxygen desaturation <90% for one cumulative minute ("early intervention") or a FVC <50% ("standard of care"). At enrollment, there was no significant correlation between FVC% and the ALSFRS-R, symptom score, MEP, MIP, or duration of nocturnal desaturation <90%. An increase in the vitality subscale of the SF-36 was demonstrated in 5/6 patients randomized to "early intervention" with NPPV. Our data indicate that FVC% correlates poorly with respiratory symptoms and suggests that MIP and nocturnal oximetry may be more sensitive measures of early respiratory insufficiency. In addition, intervention with NPPV earlier than our current standard of care may result in improved quality of life.

Amyotrophic lateral sclerosis care in Italy: a nationwide study in neurological centers

Recently, formal standards for the management of amyotrophic lateral sclerosis (ALS) have been proposed by the American Academy of Neurology (AAN). However, there are few information about the actual care of ALS. We have assessed the management of ALS in Italy in various clinical settings, on basis of a self-reported questionnaire. Thirty-six out of the 80 Italian ALS neurological departments with a particular interest in ALS care answered the questionnaire. The centers were subdivided according the mean number of patients currently followed-up (> or =30 vs. <30). An integrated health-care team for ALS existed in all large centers but only in 14% of small centers (p=0.0001). Diagnosis was communicated to most but not all patients. Symptomatic therapies were generally offered to patients in all centers. Nutritional interventions, including percutaneous endoscopic gastrostomy (PEG), were proposed by most centers, but the percentage of patients who underwent PEG was significantly higher in large centers (p=0.04). Respiratory management seemed to be lacking both in large and in small centers since non-invasive positive pressure ventilation (NIPPV) was proposed by only 70% of large and 50% of small centers; however, the percentage of patients who underwent NIPPV was significantly higher in large centers (p=0.03). Moreover, the discussion of respiratory issues was performed quite late in the course of the disease, usually when the patients have first respiratory symptoms. Therefore, there are considerable opportunities to improve the care of ALS patients in Italy, primarily through the education of neurologists on AAN standards of care for ALS.

The effect of non-invasive positive pressure ventilation (NIPPV) on cognitive function in amyotrophic lateral sclerosis (ALS): a prospective study

OBJECTIVES

Neuropsychological investigations have shown a degree of cognitive dysfunction in a proportion of non-demented patients with ALS. Respiratory muscle weakness in ALS can lead to nocturnal hypoventilation, resulting in sleep disturbance and daytime somnolence. Sleep deprivation of this type may cause impairments in cognitive function, but this has not been formally evaluated in ALS.

METHODS

Cognitive functioning was evaluated in nine patients with ALS with sleep disturbance caused by nocturnal hypoventilation (NIPPV group), and in a comparison group of 10 similar patients without ventilation problems (control group). The NIPPV group then started non-invasive positive pressure ventilation (NIPPV) at night. After about 6 weeks, change in cognitive function was evaluated.

RESULTS

Statistically significant improvement in scores on two of the seven cognitive tests was demonstrated in the NIPPV group postventilation, and a trend towards significant improvement was found for two further tests. Scores in the control group did not improve significantly for these four tests, although an improvement was found on one other test.

CONCLUSIONS

Nocturnal hypoventilation and sleep disturbance may cause cognitive dysfunction in ALS. These deficits may be partially improved by NIPPV over a 6 week period. This has important implications for investigations of both cognitive dysfunction in non-demented patients with ALS, and the effect of ventilation on quality of life.

Current management of ALS: comparison of the ALS CARE Database and the AAN Practice Parameter. The American Academy of Neurology

BACKGROUND

The American Academy of Neurology (AAN) ALS Practice Parameter was published in April 1999. The ALS CARE Database has been collecting data on the management of patients with ALS in North America since 1996.

OBJECTIVE

To compare the management of patients with ALS in North America as recorded in the ALS CARE Database with the recommendations of the AAN ALS Practice Parameter.

METHODS

Data were analyzed from 2018 patients at enrollment and from 373 of these patients who died between enrollment and May 1999.

RESULTS

Eighty-two percent of the enrolled patients reported that they had been given enough information about ALS. Only 54% of patients with drooling were receiving medication for this problem. Only 41% of those who reported being depressed most of the time were receiving antidepressant medications. Only 28% of those with dyspnea and only 9.2% of those with a forced vital capacity <40% predicted were receiving noninvasive positive pressure ventilator support. Only 30% of those with moderate to severe dysphagia had a gastrostomy tube. Half of the patients who died did so at home, but only 47% of them received residential hospice services. Although 89% of patients who died were recorded as having done so peacefully, 17% were reported to have had breathing difficulties (i.e., respiratory distress), 8% anxiety, 3.3% pain, and 2.5% choking. Advance directives were in place for 90% of the patients who died, and in 97% of cases these directives were followed.

CONCLUSIONS

These findings indicate that in the 3-year period prior to the publication of the AAN Practice Parameter, many but not all patients received the care that is recommended in that parameter; there were deficiencies, particularly in the key areas of gastrostomy and noninvasive positive pressure ventilation.

Respiratory Failure or Impairment in Amyotrophic Lateral Sclerosis

Respiratory complications account for the majority of deaths occurring in patients suffering from amyotrophic lateral sclerosis (ALS). Patients normally succumb to their illness within an average of 3 to 5 years from the time of diagnosis from complications such as hypoventilation, hypoxemia, hypercarbia, aspiration, and other pneumonia and pulmonary emboli. Although invariably disabling, ALS need not be fatal if respiratory involvement is detected early, which will allow sufficient time to discuss and implement treatment options. The recently published American Academy of Neurology guidelines for the management of ALS recommends the following: Serial measures of pulmonary function to guide management and determine prognosis. Noninvasive ventilatory support--an effective initial therapy for symptomatic chronic hypoventilation and prolonged survival. Invasive ventilatory support when long-term survival is the goal and noninvasive support is no longer sufficient. Physicians respect the right of the patient to choose, refuse, or withdraw ventilatory support. Liberal use of opiates and anxiolytics to relieve dyspnea and anxiety when ventilatory support is refused or withdrawn.

Objective measures of the efficacy of noninvasive positive-pressure ventilation in amyotrophic lateral sclerosis

The impact of noninvasive positive-pressure ventilation (NIPPV) on pulmonary function studies, quality of life, and survival was assessed in patients with amyotrophic lateral sclerosis. NIPPV did not change the rate of decline of the forced vital capacity (FVC) and forced expiratory volume in the first second (FEV(1)) (2.31 and 2.09 percent-predicted points per month, respectively). NIPPV resulted in a drop of FEV(1) by 5.94 percent-predicted points (P = 0.07), and of maximal inspiratory pressure by 6.33 percent-predicted points (P = 0.11). The change in FEV(1) and FVC pre- and postintervention correlated with the corresponding change in maximal inspiratory pressure. Fatigue and mastery scores were improved by NIPPV. Median survivals in patients intolerant and tolerant of NIPPV were 5 and 20 months, respectively (P = 0.002). Although NIPPV has no impact on the rate of decline of lung function and may have deleterious effects on spirometric measures, it may improve quality of life and survival.

Development of a patient-specific dyspnoea questionnaire in motor neurone disease (MND): the MND dyspnoea rating scale (MDRS)

Motor neurone disease (MND) is a progressive, unremitting and fatal disease. Respiratory dysfunction is common and a significant cause of morbidity. The relationship between subjective dyspnoea and objective measures of lung function have been unexplored in MND. Increasing interest in the specific treatment of respiratory symptoms in MND has highlighted the need for simple, reliable and valid measures to quantify the degree of dyspnoea in this condition. Several generic questionnaires have been developed to rate subjective breathlessness but are inappropriate for use in MND patients as they often assess dyspnoea by exercise-limitation. As yet, there are no published disease-specific measures to assess dyspnoea in MND. In order to accurately and reproducibly measure the subjective experience of dyspnoea in this patient group, we have developed and validated a novel patient-specific dyspnoea questionnaire, the MND dyspnoea rating scale (MDRS). It comprises three domains covering dyspnoea, emotion and mastery and is valid for use in MND patients at all stages of disease progression. In our cohort of 40 unselected patients with MND we have shown that the patients subjective experience of dyspnoea is closely related to emotion and psychological control over the disease. Dyspnoea is not related to objective measures of lung function such as vital capacity, irrespective of limb or bulbar presentation. In conclusion, vital capacity, although useful prognostically, is only one aspect of respiratory function in MND. The MDRS is a reliable and valid tool to rate subjective dyspnoea in MND.