Pulmonary complications of chronic neuromuscular diseases and their management

Respiratory Involvement in Patients with Neuromuscular Diseases: A Narrative Review

Respiratory muscle weakness is a major cause of morbidity and mortality in patients with neuromuscular diseases (NMDs). Respiratory involvement in NMDs can manifest broadly, ranging from milder insufficiency that may affect only sleep initially to severe insufficiency that can be life threatening. Patients with neuromuscular diseases exhibit very often sleep-disordered breathing, which is frequently overlooked until symptoms become more severe leading to irreversible respiratory failure necessitating noninvasive ventilation (NIV) or even tracheostomy. Close monitoring of respiratory function and sleep evaluation is currently the standard of care. Early recognition of sleep disturbances and initiation of NIV can improve the quality of life and prolong survival. This review discusses the respiratory impairment during sleep in patients with NMDs, the diagnostic tools available for early recognition of sleep-disordered breathing and the therapeutic options available for overall respiratory management of patients with NMDs.

Polysomnography findings in pediatric spinal muscular atrophy types 1-3

BACKGROUND

Sleep disordered breathing (SDB) causes sleep disturbance and daytime symptoms in children with neuromuscular disorders. Although polysomnography (PSG) findings are well described in many neuromuscular disorders, there are limited reports from children with spinal muscular atrophy (SMA). The aim of this study was to determine the sleep architecture and breathing characteristics and non-invasive ventilation (NIV) use in our pediatric SMA cohort.

METHODS

We conducted a cross-sectional cohort study of all children with SMA in Queensland, Australia. Children were Nusinersen naïve and had a full diagnostic PSG in 2018. The PSG was scored and reported by a single pediatric sleep physician in accordance with American Academy of Sleep Medicine Criteria (2012).

RESULTS

In sum, 31 children (18 males), Six with Type 1, 16 with Type 2 and nine with Type 3, aged 0.25-18.8 years old were studied. SDB was seen in each SMA type and was more pronounced during rapid eye movement (REM) sleep. Type 1: all patients exhibited SDB, three (50%) with central sleep apnea (CSA) and three (50%) with mixed disease. Type 2: five (31%) had CSA, one (6%) mixed disease, seven (44%) had early SDB and three (19%) had normal sleep breathing. Type 3: four (44%) children had CSA and five had early SDB. No child exhibited obstructive sleep apnea (OSA) alone.Starting NIV significantly reduced mean total PSG Apnea-Hypopnea Index (AHI) scores from a grouped mean of 15.4 events per hour (SD ± 14.6; 95% CI 6.1-24.7) to 4.0 events per hour (SD ± 4.2, 95% CI 1.2-6.5, p = 0.01).

CONCLUSION

SDB is common in children with SMA and was present in all types. CSA was the most common disorder; with mixed SDB also present in type 1 and 2 SMA.

Respiratory repercussions of neurological diseases and how best to manage them

Introduction: The high incidence of respiratory impairments in patients with neurological diseases is recognized, but the design, dosage, and effectiveness of interventions to manage them are seen as an ongoing challenge.Areas covered: This article summarizes the evidence regarding the respiratory impairments in major neurological diseases, and how to best manage them.Expert opinion: On the balance of available evidence, respiratory impairments are part of the clinical profile of neurological diseases including Multiple Sclerosis, Stroke, and Parkinson's Disease, acquiring more importance as the pathologies progress. It is recognized that knowledge gaps remain in some areas of relevance related to respiratory function and further research is required. When considering the therapeutic options, the respiratory training emerges as the approach with most evidence. However, important questions remain unsolved: what kind, how much, and how to best include respiratory interventions is uncertain. At present, respiratory programs also fail to include clinically relevant factors such as ambulation and trunk stability.

Use of an Accelerated Discharge Pathway in Patients With Severe Cerebral Palsy Undergoing Posterior Spinal Fusion for Neuromuscular Scoliosis

BACKGROUND

Implementation of a coordinated multidisciplinary postoperative pathway has been shown to reduce length of stay after posterior spinal fusion (PSF) for adolescent idiopathic scoliosis. This study sought to compare the outcomes of nonambulatory cerebral palsy (CP) patients treated with PSF and cared for using an accelerated discharge (AD) pathway with those using a more traditional discharge (TD) pathway.

METHODS

A total of 74 patients with Gross Motor Function Classification System (GMFCS) class 4/5 CP undergoing PSF were reviewed. Thirty consecutive patients were cared for using a TD pathway, and 44 patients were subsequently treated using an AD pathway. The cohorts were then evaluated for postoperative complications and length of stay.

RESULTS

Length of stay (LOS) was 19% shorter in patients managed with the AD pathway (AD 4.0 days [95% CI 2.5-5.5] vs. TD 4.9 days [95% CI 3.5-6.3], p = .01). There was no difference between groups with respect to age at surgery, GMFCS class, preoperative curve magnitude, pelvic obliquity, kyphosis, postoperative curve correction, fusion to the pelvis, or length of fusion between groups. Length of stay remained significantly shorter in the AD group by 0.9 days when controlling for estimated blood loss (EBL) and length of surgery. Complication rates trended lower in the AD group (33% AD vs. 52% TD, p = .12), including pulmonary complications (21% AD vs. 38% TD, p = .13). There was no significant difference in wound complications, return to the operating room, or medical readmissions between groups.

CONCLUSIONS

Adoption of a standardized postoperative pathway reduced LOS by 19% in nonambulatory CP patients. Overall, complications, including pulmonary, trended lower in the AD group. Early discharge appears to be possible in this challenging patient population. Although the AD pathway may not be appropriate for all patients, the utility of the AD pathway in optimizing care for more routine PSF for this patient subset appears to be worthwhile.

LEVEL OF EVIDENCE

Level III, therapeutic.

Transition to adult care in young people with neuromuscular disease on non-invasive ventilation

BACKGROUND

Long-term mechanical ventilation (LTV) with non-invasive ventilation (NIV) prolongs survival in patients with Neuromuscular Diseases (NMDs). Transition from paediatric to adult healthcare system is an undervalued and challenging issue for children with chronic conditions on mechanical ventilation.

METHODS

this retrospective study aims to compare issues of young adults in age to transition to adult care (≥ 15 years old) affected by NMDs on NIV in two different Paediatric Respiratory Units in two different countries: Bambino Gesù Children's Hospital, Research Institute, (Rome, Italy) (BGCH) and the Paediatric Respiratory Unit of the Royal Brompton Hospital (London, UK) (RBHT).

RESULTS

The median (min-max) age at starting ventilation was significantly different in the two groups (16 years old vs 12, p = 0.0006). We found significant difference in terms of median age at the time of observation (18 (15-22) vs 17 (15-19) years, p = 0.0294) and of type of referral (all the patients from the BGCH group were referred to paediatric services (n = 15, 100%), median age 18 (15-22); only 6 patients, in the RBHT group, with a median age 15.50 (15-17) years, were entirely referred to paediatric service). We found different sleep-disordered breathing assessments 6 full Polysomnographies, 7 Cardio-Respiratory Polygraphies and 2 oximetry with capnography (SpO2-tcCO2) studies in the BCGH group, while all patients of RBHT group were assessed with an SpO2-tcCO2 study. All patients from both groups underwent multidisciplinary assessment.

CONCLUSIONS

In conclusion, patients with NMDs on NIV in age to transition to adult require complex multidisciplinary management: significant efforts are needed to achieve the proper transition to adult care.

Assessing Diaphragm Function in Chest Wall and Neuromuscular Diseases

Diaphragm dysfunction is defined as the partial or complete loss of diaphragm muscle contractility. However, because the diaphragm is one of only a few skeletal muscles that is not amenable to direct examination, the tools available for the clinician to assess diaphragm function have been limited. Traditionally, measures of lung volume, inspiratory muscle strength, and radiographic techniques such as fluoroscopy have provided the major method to assess diaphragm function. Measurement of transdiaphragmatic pressure provides the most direct means of evaluating the diaphragm, but this technique is not readily available to clinicians. Diaprhragm ultrasonography is new method that allows for direct examination of the diaphragm.

Pulmonary Function Testing in Neuromuscular and Chest Wall Disorders

Neuromuscular and chest wall disorders frequently compromise pulmonary function, and thorough respiratory evaluation often can assist in diagnosis, risk assessment, and prognosis. Because many of these disorders can be progressive, serial assessments are necessary to best define a trajectory of impairment (or improvement with therapy). This article covers the major respiratory testing modalities available in the evaluation of these patients, emphasizing both the benefits and shortcomings of each approach. Most parameters are available in a standard pulmonary laboratory (flows, volumes, static pressures), although referral to a specialized center may be necessary to conclusively evaluate a given patient.

Pathophysiology of Neuromuscular Respiratory Diseases

Gas exchange between the atmosphere and the human body depends on the lungs and the function of the respiratory pump. The respiratory pump consists of the respiratory control center located in the brain, bony rib cage, diaphragm, and intercostal, accessory, and abdominal muscles. A variety of muscles serve to fine-tune adjustments of ventilation to metabolic demands. Appropriate evaluation and interventions can prevent respiratory complications and prolong life in individuals with neuromuscular diseases. This article discusses normal function of the respiratory pump, general pathophysiologic issues, and abnormalities in more common neuromuscular diseases.

Perfil clínico e funcional dos pacientes com Distrofia Muscular de Duchenne assistidos na Associação Brasileira de Distrofia Muscular (ABDIM)

A distrofia muscular de Duchenne (DMD) é uma doença hereditária progressiva, de herança recessiva ligada ao cromossomo X. As manifestações clínicas se iniciam na infância com enfraquecimento muscular progressivo. Objetivo: Foi caracterizar o perfil clínico e funcional apresentado pelos pacientes com DMD, que se encontravam em acompanhamento na Associação Brasileira de Distrofia Muscular (ABDIM). Método: Foram coletados os dados de 58 pacientes com o diagnóstico de DMD. Resultados: Os resultados obtidos caracterizaram os pacientes com DMD da ABDIM, proporcionando dados como: idade da população, complicações clínicas mais freqüentes e nível de independência em relação á funcionalidade, caracterizando a diversidade do perfil clínico e funcional desses pacientes. Conclusão: Concluiu-se que o perfil clínico e funcional dos pacientes da ABDIM apresentou-se heterogêneo, mostrando que a progressão da doença varia de sujeito para sujeito dentro da população estudada, mesmo levando em consideração a faixa etária.

Assessment of diaphragm motion using ultrasonography in a patient with facio-scapulo-humeral dystrophy: A case report

RATIONALE

Diaphragm is the main inspiratory respiratory muscle and little is known about diaphragm ultrasound in facio-scapula-humeral muscular dystrophy, a neuromuscular disease characterized by an asymmetric skeletal muscle involvement.

PATIENT CONCERNS

Diaphragm function evaluation DIAGNOSIS:: Diaphragm muscle weakness attested by the drop of vital capacity (VC) value from sitting position (74%) to supine position (46%).

INTERVENTIONS

A diaphragm ultrasound was performed in supine position, from the anterior subcostal window OUTCOMES:: We found an opposite side to side hemi diaphragm displacement, either during sniff maneuver or during deep inspiration maneuver, showing a cranial abnormal reduced motion of the right hemi diaphragm whereas the left hemi diaphragm moved caudally.

LESSONS

Diaphragm weakness may be present with an asymmetric pattern and an opposite motion during inspiration or sniff manoeuver in facio-scapula-humeral muscular dystrophy. A future study with a systematic evaluation of a greater number of FSHD1 patients will be necessary to characterize this population.

Comparison of arterial and venous blood gases in patients with obesity hypoventilation syndrome and neuromuscular disease

OBJECTIVES:

Obesity hypoventilation syndrome (OHS) and some neuromuscular diseases (NMD) present with hypercapnic respiratory failure. Arterial blood gas (ABG) analysis is important in the diagnosis, follow-up, and treatment response of these diseases. However, ABG sampling is difficult in these patients because of excessive subcutaneous fat tissue, muscle atrophy, or contracture. The aim of this study is to investigate the value of venous blood gas (VBG), which is an easier and less complicated method, among stable patients with OHS and NMD.

METHODS:

The study included stable OHS and NMD patients who had been previously diagnosed and followed up between March 2017 and May 2017 in the outpatient clinic. ABG was taken from all patients in room air, and peripheral VBG was taken within 5 min after ABG sampling.

RESULTS:

Thirty-six patients with OHS and 46 patients with NMD were included in the study. There was a moderate positive correlation between arterial and venous pH values for all patients (r_s = 0.590, P < 0.001). There were a strong and very strong positive correlations between arterial and venous pCO₂ and HCO₃ values (r_s = 0.725 and r_s = 0.934, respectively) (P < 0.001). There was no correlation between arterial and venous pO₂ and saturation values. There was an agreement in Bland–Altman method for the values of ABG and VBG (pH, pCO₂, and HCO₃).

CONCLUSIONS:

There was a correlation between ABG and VBG values (pH, pCO₂, and HCO₃). VBG parameters (pH, pCO₂, and HCO₃) can be used safely instead of ABG parameters which have many risks, during treatment and follow-up of patients with OHS and NMD.

The effect of intrapulmonary percussive ventilation in pediatric patients: A systematic review

BACKGROUND

Intrapulmonary percussive ventilation (IPV) is frequently used in clinical practice to enhance sputum evacuation and lung recruitment. However, the evidence in different respiratory pathologies, especially in children, is still lacking. This systematic review aims to enlist the effectiveness of IPV as an airway clearance technique in pediatric patients.

DATA SOURCES

A systematic literature search was performed in PubMed, Web of Science, and the Cochrane Library databases.

STUDY SELECTION

Studies were included if the subjects suffered from a respiratory disease requiring airway clearance and the mean age of the sample was <18 years. After screening, nine articles remained for further analysis.

RESULTS

Three of the nine articles examined patients with cystic fibrosis (CF). No significant differences in lung function or expectorated mucus were found compared to conventional chest physiotherapy. On the other hand, significant beneficial results were found for the treatment or prevention of atelectasis in non-CF patients using IPV. Similar results were seen when comparing therapies for neuromuscular/neurological patients. One study found that IPV reduced hospital stay and improved the clinical status of children with acute bronchiolitis compared to no physiotherapy. Severe adverse events did not occur in the included studies.

CONCLUSION

A limited number of studies investigated IPV in the pediatric population. Despite the heterogeneity across the studies and the small sample sizes, the results seem promising. IPV is suggested to be a safe and effective alternative for airway clearance. Future research is required to confirm these results and to further analyze the possible benefits in different respiratory pathologies.

Hypoglossal Motor Neuron Death Via Intralingual CTB-saporin (CTB-SAP) Injections Mimic Aspects of Amyotrophic Lateral Sclerosis (ALS) Related to Dysphagia

Amyotrophic lateral sclerosis (ALS) is a devastating disease leading to degeneration of motor neurons and skeletal muscles, including those required for swallowing. Tongue weakness is one of the earliest signs of bulbar dysfunction in ALS, which is attributed to degeneration of motor neurons in the hypoglossal nucleus in the brainstem, the axons of which directly innervate the tongue. Despite its fundamental importance, dysphagia (difficulty swallowing) and strategies to preserve swallowing function have seldom been studied in ALS models. It is difficult to study dysphagia in ALS models since the amount and rate at which hypoglossal motor neuron death occurs cannot be controlled, and degeneration is not limited to the hypoglossal nucleus. Here, we report a novel experimental model using intralingual injections of cholera toxin B conjugated to saporin (CTB-SAP) to study the impact of only hypoglossal motor neuron death without the many complications that are present in ALS models. Hypoglossal motor neuron survival, swallowing function, and hypoglossal motor output were assessed in Sprague-Dawley rats after intralingual injection of either CTB-SAP (25 g) or unconjugated CTB and SAP (controls) into the genioglossus muscle. CTB-SAP treated rats exhibited significant (p ≤ 0.05) deficits vs. controls in: (1) lick rate (6.0 ± 0.1 vs. 6.6 ± 0.1 Hz; (2) hypoglossal motor output (0.3 ± 0.05 vs. 0.6 ± 0.10 mV); and (3) hypoglossal motor neuron survival (398 ± 34 vs. 1018 ± 41 neurons). Thus, this novel, inducible model of hypoglossal motor neuron death mimics the dysphagia phenotype that is observed in ALS rodent models, and will allow us to study strategies to preserve swallowing function.

Telemedicine for Facio-Scapulo-Humeral Muscular Dystrophy: A multidisciplinary approach to improve quality of life and reduce hospitalization rate?

BACKGROUND

Facio-Scapulo-Humeral Muscular Dystrophy (FSHD) is an autosomal dominant inherited disorder characterized by a variable and asymmetric involvement of facial, trunk, upper and lower extremity muscles. Although respiratory weakness is a relatively unknown feature of FSHD, it is not rare. Telemedicine has been used in a variety of health care fields, but only recently, with the advent of sophisticated technology, its interest among health professionals became evident, even in such diseases.

OBJECTIVE

To demonstrate the telemedicine efficacy in FSHD.

METHODS

Four siblings affected by a severe form of FSHD, living in a rural area far away from the referral center for neuromuscular diseases, who used a wheelchair, suffered from chronic respiratory failure and were provided with long-term non-invasive mechanical ventilation, received a 6-month period of telemedicine support. This consisted of video conferencing (respiratory physiotherapy, psychological support, neurological and pneumological assessment, nurse-coach supervision) and telemonitoring of cardiorespiratory variables (oxygen saturation, blood pressure, and heart rate).

RESULTS

We performed 540 video conference sessions per patient, including three daily contacts with short monitoring oximetry measurements, blood pressure, and heart-rate measurements, psychological support, neurological and pneumological assessment, nurse-coach supervision.

CONCLUSIONS

Our findings indicate that our telemedicine system was user-friendly, efficient for the home treatment of FSHD, and allowed reducing hospital admissions.

A middle-aged man with generalised weakness and dyspnoea

A 50-year-old male presented with progressive breathlessness and generalised muscular weakness for the last 10 days. He felt extremely weak and could barely walk due to breathlessness. His dyspnoea was increased when lying down and decreased by an upright posture. He had no other respiratory or cardiac symptoms.

Can you diagnose this middle-aged man with generalised weakness and dyspnoea?http://ow.ly/mSuQ30dxQ5o

Neuromuscular disorders and chronic ventilation

Morbidity and mortality have decreased in patients with neuromuscular disease due to implementation of therapies to augment cough and improve ventilation. Infants with progressive neuromuscular disease will eventually develop respiratory complications as a result of muscle weakness and their inability to compensate during periods of increased respiratory loads. The finding of nocturnal hypercapnia is often the trigger for initiating non-invasive ventilation and studies have shown that its use not only may improve sleep-disordered breathing, but also that it may have an effect on daytime function, symptoms related to hypercapnia, and partial pressure of CO₂. It is important to understand the respiratory physiology of this population and to understand the benefits and limitations of assisted ventilation.

Maximum inspiratory pressure as a clinically meaningful trial endpoint for neuromuscular diseases: a comprehensive review of the literature

Respiratory muscle strength is a proven predictor of long-term outcome of neuromuscular disease (NMD), including amyotrophic lateral sclerosis, Duchenne muscular dystrophy, and spinal muscular atrophy. Maximal inspiratory pressure (MIP), a sensitive measure of respiratory muscle strength, one of several useful tests of respiratory muscle strength, is gaining interest as a therapeutic clinical trial endpoint for NMD. In this comprehensive review we investigate the use of MIP as a measure of respiratory muscle strength in clinical trials of therapeutics targeting respiratory muscle, examine the correlation of MIP with survival, quality of life, and other measures of pulmonary function, and outline the role of MIP as a clinically significantly meaningful outcome measure. Our analysis supports the utility of MIP for the early evaluation of respiratory muscle strength, especially of the diaphragm, in patients with NMD and as a surrogate endpoint in clinical trials of therapies for NMD.

Support and rehabilitation of patients with pulmonary expansion deficit by using game therapy

Patients suffering from hypoventilation and pulmonary expansion deficit are at increased risk of developing pulmonary complications such as atelectasis, pneumonia or pleural effusion. These complications can increase the length of stay and spending on health, and generate long-term functional impairment. This study aims to produce a therapeutic alternative to the traditional method of lung re-expansion through incentive spirometry (IS) using the game therapy to build an innovative system. This system makes use of infrared and Bluetooth communication technology to associate the game therapy to EI. At the end of the system implementation, we expect to obtain good adhesion of the patient and the physiotherapists.

The Effectiveness of Singing or Playing a Wind Instrument in Improving Respiratory Function in Patients with Long-Term Neurological Conditions: A Systematic Review

BACKGROUND

Many long-term neurological conditions adversely affect respiratory function. Singing and playing wind instruments are relatively inexpensive interventions with potential for improving respiratory function; however, synthesis of current evidence is needed to inform research and clinical use of music in respiratory care.

OBJECTIVE

To critically appraise, analyze, and synthesize published evidence on the effectiveness of singing or playing a wind instrument to improve respiratory function in people with long-term neurological conditions.

DESIGN

Systematic review of published randomized controlled trials and observational studies examining singing or playing wind instruments to improve respiratory function in individuals with long-term neurological conditions.

METHODS

Articles meeting specified inclusion criteria were identified through a search of the Medline, Embase, PsycINFO, Cochrane Library, CINAHL, Web of Science, CAIRSS for Music, WHO International Clinical Trials Registry Platform Search Portal, and AMED databases as early as 1806 through March 2015. Information on study design, clinical populations, interventions, and outcome measures was extracted and summarized using an electronic standardized coding form. Methodological quality was assessed and summarized across studies descriptively.

RESULTS

From screening 584 references, 68 full texts were reviewed and five studies included. These concerned 109 participants. The studies were deemed of low quality, due to evidence of bias, in part due to intervention complexity. No adverse effects were reported. Overall, there was a trend toward improved respiratory function, but only one study on Parkinson's disease had significant between-group differences.

CONCLUSIONS

The positive trend in respiratory function in people with long-term neurological conditions following singing or wind instrument therapy is of interest, and warrants further investigation.

[Non-invasive and invasive out of hospital ventilation in chronic respiratory failure : Consensus report of the working group on ventilation and intensive care medicine of the Austrian Society of Pneumology]

The current consensus report was compiled under the patronage of the Austrian Society of Pneumology (Österreichischen Gesellschaft für Pneumologie, ÖGP) with the intention of providing practical guidelines for out-of-hospital ventilation that are in accordance with specific Austrian framework parameters and legal foundations. The guidelines are oriented toward a 2004 consensus ÖGP recommendation concerning the setup of long-term ventilated patients and the 2010 German Respiratory Society S2 guidelines on noninvasive and invasive ventilation of chronic respiratory insufficiency, adapted to national experiences and updated according to recent literature. In 11 chapters, the initiation, adjustment, and monitoring of out-of-hospital ventilation is described, as is the technical equipment and airway access. Additionally, the different indications-such as chronic obstructive pulmonary diseases, thoracic restrictive and neuromuscular diseases, obesity hypoventilation syndrome, and pediatric diseases-are discussed. Furthermore, the respiratory physiotherapy of adults and children on invasive and noninvasive long-term ventilation is addressed in detail.

Physiology of respiratory disturbances in muscular dystrophies

Muscular dystrophy is a group of inherited myopathies characterised by progressive skeletal muscle wasting, including of the respiratory muscles. Respiratory failure, i.e. when the respiratory system fails in its gas exchange functions, is a common feature in muscular dystrophy, being the main cause of death, and it is a consequence of lung failure, pump failure or a combination of the two. The former is due to recurrent aspiration, the latter to progressive weakness of respiratory muscles and an increase in the load against which they must contract. In fact, both the resistive and elastic components of the work of breathing increase due to airway obstruction and chest wall and lung stiffening, respectively. The respiratory disturbances in muscular dystrophy are restrictive pulmonary function, hypoventilation, altered thoracoabdominal pattern, hypercapnia, dyspnoea, impaired regulation of breathing, inefficient cough and sleep disordered breathing. They can be present at different rates according to the type of muscular dystrophy and its progression, leading to different onset of each symptom, prognosis and degree of respiratory involvement.

KEY POINTS

A common feature of muscular dystrophy is respiratory failure, i.e. the inability of the respiratory system to provide proper oxygenation and carbon dioxide elimination.In the lung, respiratory failure is caused by recurrent aspiration, and leads to hypoxaemia and hypercarbia.Ventilatory failure in muscular dystrophy is caused by increased respiratory load and respiratory muscles weakness.Respiratory load increases in muscular dystrophy because scoliosis makes chest wall compliance decrease, atelectasis and fibrosis make lung compliance decrease, and airway obstruction makes airway resistance increase.The consequences of respiratory pump failure are restrictive pulmonary function, hypoventilation, altered thoracoabdominal pattern, hypercapnia, dyspnoea, impaired regulation of breathing, inefficient cough and sleep disordered breathing.

EDUCATIONAL AIMS

To understand the mechanisms leading to respiratory disturbances in patients with muscular dystrophy.To understand the impact of respiratory disturbances in patients with muscular dystrophy.To provide a brief description of the main forms of muscular dystrophy with their respiratory implications.

The Prognostic Role of Obstructive Sleep Apnea at the Onset of Amyotrophic Lateral Sclerosis

BACKGROUND/OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive loss of central and peripheral motor neurons. Some studies have found discordant data in the presence of sleep apnea in ALS patients. An obstructive component also occurs with upper airways hypotonia and muscle weakness that may result in an excessive reduction of airway lumen, leading to obstructive sleep apnea (OSA). The aim of this study was to assess the role of obstructive apneic events at disease onset in the ALS prognosis.

METHODS

A longitudinal retrospective study was conducted on 42 clinically diagnosed ALS patients. The study population was divided into 2 groups according to their obstructive apnea/hypopnea index (AHIo): group 1 consisted of 20 patients with an AHIo ≥5 and group 2 consisted of 22 patients with an AHIo <5. Both groups were compared with regard to demographic, polygraphic, and respiratory function parameters as well as ALS characteristics (bulbar onset, time between onset and first check-up, time between diagnosis and first check-up, time between first check-up and death or tracheostomy).

RESULTS

The mean survival in ALS patients with an AHIo ≥5 was significantly shorter than in ALS without OSA (p = 0.0237). The sniff nasal inspiratory pressure test was significantly correlated with AHIo, time of oxyhemoglobin saturation below 90% and the oxyhemoglobin desaturation index (p < 0.0001).

CONCLUSIONS

Our study highlights the importance of an early diagnosis of OSA in ALS patients, allowing the identification of ALS patients with an OSA phenotype (AHIo ≥5), who are characterized by a worse prognosis.

Benefits of interventions for respiratory secretion management in adult palliative care patients-a systematic review

BACKGROUND

Respiratory secretions impact negatively on palliative patients. Unfortunately, a gold standard therapy is not yet available. The purpose of this study was to identify which interventions are in use to control respiratory secretions in patients with chronic disease with a poor prognosis and verify their effects on outcomes relevant for palliative care patients.

METHODS

A systematic review of the literature with narrative summary was conducted. We searched eight electronic databases in April (6th), 2016. Citation-tracking and reference list searches were conducted. We included randomized controlled trials, crossover trials, observational and qualitative studies regarding interventions for respiratory secretion management in adult patients with chronic diseases that met inclusion criteria indicating short prognosis.

RESULTS

Six randomized controlled trials, 11 observational studies, ten crossover trials and one qualitative study were found. Interventions included mechanical insufflation-exsufflation (MIE), expiratory muscle training, manually-assisted cough, tracheotomy, chest physiotherapy, suctioning, air stacking, electrical stimulation of abdominal muscles, nebulized saline, positive expiratory pressure masks, percussive ventilation, high frequency chest wall oscillations. The interventions with most promising benefits to patients in palliative care were manually-assisted cough and mechanical insufflation-exsufflation to promote expectoration and percussive ventilation to improve mucous clearance.

CONCLUSION

Therapies, such as manually assisted cough, mechanical insufflation-exsufflation and percussive ventilation, which aim to deal with respiratory secretion, were the most promising treatment for use in palliative care for specific diseases. Nevertheless, the evidence still needs to improve in order to identify which treatment is the best.

Cardiac implantable electronic devices in tracheotomized muscular dystrophy patients: Safety and risks

BACKGROUND/OBJECTIVES

Muscular dystrophies are genetic muscle disorders, in which heart involvement and chronic respiratory impairment affect survival. Cardiac conduction disturbances require implantable cardiac pacemaker. Implantable defibrillators may also be necessary to prevent cardiac sudden death. The safety and risk of cardiac electronic devices' implantation are not known in patients with muscular dystrophy. We aimed to assess the risks related to cardiac implantable electronic devices (CIED) in muscular dystrophy patients ventilated by tracheostomy.

METHODS

We reviewed all medical charts of neuromuscular patients and identified all CIED implantations of pacemakers (PM) or defibrillators (ICD) in patients ventilated using tracheostomy.

RESULTS

Twelve device implantations were included, performed in 9 patients (5 DMD, 1 Becker muscular dystrophy and 3 DM1). Mean age was 39.9years±13.0. All patients were wheel-chair bound and tracheotomized. Six pacemakers (PM) and 6 cardiac resynchronization (CRT) devices, including 2 defibrillators (CRT-D) were implanted. Following device implantation, two patients had a pneumothorax and one died from severe heart failure after an unsuccessful CRT implant attempt. Follow-up lasted up to 8years (mean 2.6±2.9years), during which one patient presented a PM pocket infection, requiring PM explantation and epicardial reimplantation.

CONCLUSION

We found a high prevalence of early complications (16.6% pneumothorax) after CIED implantation and an acceptable long-term infectious risk (8.3%). These results highlight the feasibility of CIED implantation in tracheotomized patients with muscular dystrophies and the need for a particular caution in the management of these patients during invasive procedures. ClinicalTrials.gov (identifier: NCT02501083).

Rural and remote care: Overcoming the challenges of distance

The challenges of providing quality respiratory care to persons living in rural or remote communities can be daunting. These populations are often vulnerable in terms of both health status and access to care, highlighting the need for innovation in service delivery. The rapidly expanding options available using telehealthcare technologies have the capacity to allow patients in rural and remote communities to connect with providers at distant sites and to facilitate the provision of diagnostic, monitoring, and therapeutic services. Successful implementation of telehealthcare programs in rural and remote settings is, however, contingent upon accounting for key technical, organizational, social, and legal considerations at the individual, community, and system levels. This review article discusses five types of telehealthcare delivery that can facilitate respiratory care for residents of rural or remote communities: remote monitoring (including wearable and ambient systems; remote consultations (between providers and between patients and providers), remote pulmonary rehabilitation, telepharmacy, and remote sleep monitoring. Current and future challenges related to telehealthcare are discussed.

Natural History of Cardiac and Respiratory Involvement, Prognosis and Predictive Factors for Long-Term Survival in Adult Patients with Limb Girdle Muscular Dystrophies Type 2C and 2D

BACKGROUND

Type 2C and 2D limb girdle muscular dystrophies (LGMD) are a group of autosomal recessive limb girdle muscular dystrophies manifested by proximal myopathy, impaired respiratory muscle function and cardiomyopathy. The correlation and the prognostic impact of respiratory and heart impairment are poorly described. We aimed to describe the long-term cardiac and respiratory follow-up of these patients and to determine predictive factors of cardio-respiratory events and mortality in LGMD 2C and 2D.

METHODS

We reviewed the charts of 34 LGMD patients, followed from 2005 to 2015, to obtain echocardiographic, respiratory function and sleep recording data. We considered respiratory events (acute respiratory failure, pulmonary sepsis, atelectasis or pneumothorax), cardiac events (acute heart failure, significant cardiac arrhythmia or conduction block, ischemic stroke) and mortality as outcomes of interest for the present analysis.

RESULTS

A total of 21 patients had type 2C LGMD and 13 patients had type 2D. Median age was 30 years [IQR 24-38]. At baseline, median pulmonary vital capacity (VC) was 31% of predicted value [20-40]. Median maximal inspiratory pressure (MIP) was 31 cmH2O [IQR 20.25-39.75]. Median maximal expiratory pressure (MEP) was 30 cm H2O [20-36]. Median left ventricular ejection fraction (LVEF) was 55% [45-64] with 38% of patients with LVEF <50%. Over a median follow-up of 6 years, we observed 38% respiratory events, 14% cardiac events and 20% mortality. Among baseline characteristics, LVEF and left ventricular end diastolic diameter (LVEDD) were associated with mortality, whilst respiratory parameters (VC, MIP, MEP) and the need for home mechanical ventilation (HMV) were associated with respiratory events.

CONCLUSION

In our cohort of severely respiratory impaired type 2C and 2D LGMD, respiratory morbidity was high. Cardiac dysfunction was frequent in particular in LGMD 2C and had an impact on long-term mortality.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02501083.

The use of volume-assured pressure support noninvasive ventilation in acute and chronic respiratory failure: a practical guide and literature review

Noninvasive positive pressure ventilation (NPPV) is an important tool in the management of acute and chronic respiratory failure. Traditionally, continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) have been the most commonly utilized modes for these purposes. Newer hybrid modes of NPPV, such as average volume-assured pressure support (VAPS), combine the properties of both volume- and pressure-controlled NPPV and represent another tool in the treatment of acute and chronic respiratory failure. Evidence demonstrating the superiority of VAPS over BPAP is sparse, but there have been studies that have demonstrated comparable efficacy between the two modes. The use of VAPS in acute hypercapnic respiratory failure has shown better clearance of CO2 compared to BPAP, due to its property of delivering a more assured tidal volume. This, however, did not lead to a decrease in hospital-days or improved mortality, relative to BPAP. The studies evaluating VAPS for chronic respiratory failure involve small sample sizes but have shown some promise. The benefits noted with VAPS, however, did not translate into increased survival, decreased hospitalizations or improved quality of life compared to BPAP. The limited evidence available suggests that VAPS is equally effective in treating acute and chronic respiratory failure compared to BPAP. Overall, the evidence to suggest superiority of one mode over the other is lacking. There is a need for larger studies before firm conclusions can be made.

Symptom Management and End-of-Life Care in Amyotrophic Lateral Sclerosis

The number of available symptomatic treatments has markedly enhanced the care of patients with amyotrophic lateral sclerosis (ALS). Once thought to be untreatable, patients with ALS today clearly benefit from multidisciplinary care. The impact of such care on the disease course, including rate of progression and mortality, has surpassed the treatment effects commonly sought in clinical drug trials. Unfortunately, there are few randomized controlled trials of medications or interventions addressing symptom management. In this review, the authors provide the level of evidence, when available, for each intervention that is currently considered standard of care by consensus opinion.

Can daytime measures of lung function predict respiratory failure in children with neuromuscular disease?

Neuromuscular disorders in children are a heterogeneous group of conditions with a variable age of presentation and overlapping clinical manifestations, many of which have progressive respiratory morbidity. Respiratory insufficiency occurs as a consequence of an imbalance between demands on the respiratory system and respiratory muscle capacity. Daytime measures of pulmonary function are used routinely in these children to assess respiratory status and monitor the consequences of the progression of muscle weakness. This review describes the current evidence for daytime pulmonary function tests and their ability to predict imminent respiratory morbidity.

Louis EK. Neuromuscular disorders and sleep in critically ill patients

Sleep-disordered breathing (SDB) is a frequent presenting manifestation of neuromuscular disorders and can lead to significant morbidity and mortality. If not recognized and addressed early in the clinical course, SDB can lead to clinical deterioration with respiratory failure. The pathophysiologic basis of SDB in neuromuscular disorders, clinical features encountered in specific neuromuscular diseases, and diagnostic and management strategies for SDB in neuromuscular patients in the critical care setting are reviewed. Noninvasive positive pressure ventilation has been a crucial advance in critical care management, improving sleep quality and often preventing or delaying mechanical ventilation and improving survival in neuromuscular patients.

Use of mechanical airway clearance devices in the home by people with neuromuscular disorders: effects on health service use and lifestyle benefits

Background

People with neuromuscular disorders (NMD) exhibit weak coughs and are susceptible to recurrent chest infections and acute respiratory complications, the most frequent reasons for their unplanned hospital admissions. Mechanical insufflation-exsufflation (MI-E) devices are a non-invasive method of increasing peak cough flow, improving cough efficacy, the clearance of secretion and overcoming atelectasis. There is limited published evidence on the impact of home use MI-E devices on health service utilisation. The aims of the study were: to assess the self-reported health and lifestyle benefits experienced as a result of home use of MI-E devices; and evaluate the effects of in-home use of MI-E devices on Emergency Department (ED) presentations, hospital admissions and inpatient length of stay (LOS).

Methods

Individuals with NMD who were accessing a home MI-E device provided through Muscular Dystrophy Western Australia were invited to participate in a quantitative survey to obtain information on their experiences and self-assessed changes in respiratory health. An ad-hoc record linkage was performed to extract hospital, ED and mortality data from the Western Australian Department of Health (DOHWA). The main outcome measures were ED presentations, hospital separations and LOS, before and after commencement of home use of an MI-E device.

Results

Thirty seven individuals with NMD using a MI-E device at home consented to participate in this study. The majority (73%) of participants reported using the MI-E device daily or weekly at home without medical assistance and 32% had used the machine to resolve a choking episode. The survey highlighted benefits to respiratory function maintenance and the ability to manage increased health care needs at home. Not using a home MI-E device was associated with an increased risk of ED presentations (RR = 1.76, 95% CI 1.1-2.84). The number of hospital separations and LOS reduced after the use of MI-E device, but not significantly. No deaths were observed in participants using the MI-E device at home.

Conclusions

Home use of a MI-E device by people living with NMD may have a potential impact on reducing their health service utilisation and risk of death. Future research with greater subject numbers and longer follow-up periods is recommended to enhance this field of study.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-015-0267-0) contains supplementary material, which is available to authorized users.

Home mechanical ventilation in childhood-onset hereditary neuromuscular diseases: 13 years' experience at a single center in Korea

Introduction

Children with hereditary neuromuscular diseases (NMDs) are at a high risk of morbidity and mortality related to respiratory failure. The use of home mechanical ventilation (HMV) has saved the lives of many children with NMD but, due to a lack of studies, dependable guidelines are not available. We drew upon our experience to compare the various underlying NMDs and to evaluate HMV with regard to respiratory morbidity, the proper indications and timing for its use, and to develop a policy to improve the quality of home noninvasive ventilation (NIV).

Methods

We retrospectively analyzed the medical records of 57 children with childhood-onset hereditary NMDs in whom HMV was initiated between January 2000 and May 2013 at Seoul National University Children's Hospital. The degree of respiratory morbidity was estimated by the frequency and duration of hospitalizations caused by respiratory distress.

Results

The most common NMD was spinal muscular atrophy (SMA, n = 33). Emergent mechanical ventilation was initiated in 44% of the patients before the confirmed diagnosis, and the indicators of pre-HMV respiratory morbidity (e.g., extubation trials, hypoxia, hospitalizations, and intensive care unit stay) were greater in these patients than in others. The proportion of post-HMV hospitalizations (range, 0.00−0.52; median, 0.01) was lower than that of pre-HMV hospitalizations (0.02−1.00; 0.99) (P < 0.001). Eight patients were able to maintain home NIV. The main causes of NIV failure were air leakage and a large amount of airway secretions.

Conclusions

The application of HMV helped reduce respiratory morbidity in children with childhood-onset hereditary NMD. Patients with SMA type I can benefit from an early diagnosis and the timely application of HMV. The choice between invasive and noninvasive HMV should be based on the patient’s age and NIV trial tolerance. Systematic follow-up guidelines provided by a multidisciplinary team are needed.

Telemedicine system for the care of patients with neuromuscular disease and chronic respiratory failure

INTRODUCTION

Neuromuscular diseases cause a number of limitations which may be improved by using a telemedicine system. These include functional impairment and dependence associated with muscle weakness, the insidious development of respiratory failure and episodes of exacerbation.

MATERIAL AND METHODS

The present study involved three patients with severe neuromuscular disease, chronic respiratory failure and long-term mechanical ventilation, who were followed up using a telemedicine platform. The telemedicine system is based on videoconferencing and telemonitoring of cardiorespiratory variables (oxygen saturation, heart rate, blood pressure and electrocardiogram). Two different protocols were followed depending on whether the patient condition was stable or unstable.

RESULTS

Over a period of 5 years, we analyzed a series of variables including use of the system, patient satisfaction and clinical impact. Overall we performed 290 videoconference sessions, 269 short monitoring oximetry measurements and 110 blood pressure measurements. With respect to the clinical impact, after enrolment in the telemedicine program, the total number of hospital admissions fell from 18 to 3.

CONCLUSIONS

Our findings indicate that the system was user friendly for patients and care givers. Patient satisfaction scores were acceptable. The telemedicine system was effective for the home treatment of three patients with severe neuromuscular diseases and reduced the need for hospital admissions.

Oral appliance to assist non-invasive ventilation in a patient with amyotrophic lateral sclerosis

BACKGROUND

From the moment the respiratory muscle groups are affected in amyotrophic lateral sclerosis (ALS), respiratory complications will be the major cause of morbidity and mortality. Untreated respiratory muscle impairment leads to respiratory insufficiency and additionally to difficulties in airway secretion clearance. Non-invasive ventilation (NIV) is the first choice in treating respiratory insufficiency in ALS as it improves sleep-related symptoms, quality of life and life expectancy. Nevertheless, NIV is not always effective, probably due to bulbar dysfunction or anatomical abnormalities. As a result, tracheostomy ventilation (TV) may become necessary.

METHODS

In this case report, we present a 60-year-old female with ALS, for whom it was not possible to provide a sufficient tidal volume with NIV. A chin lift was performed while the patient was awake to see if a more anterior jaw position would lead to an increased tidal volume. As this was the case, a mandibular advancement device (MAD) was fabricated.

RESULTS

With a combination of a MAD and NIV, the upper airway obstructions were overcome and a good ventilation and adherence to therapy were seen.

CONCLUSIONS

When there is the presumption of airway obstructions in combination with an ineffective NIV, we advise to perform a chin lift to assess whether the obstructions can be overcome by a more anterior jaw position. If that is the case, NIV may be combined with MAD to establish effective ventilation and avoid the use of TV.

[Respiratory treatments in neuromuscular disease]

In a previous article, a review was presented of the respiratory pathophysiology of the patient with neuromuscular disease, as well as their clinical evaluation and the major complications causing pulmonary deterioration. This article presents the respiratory treatments required to preserve lung function in neuromuscular disease as long as possible, as well as in special situations (respiratory infections, spinal curvature surgery, etc.). Special emphasis is made on the use of non-invasive ventilation, which is changing the natural history of many of these diseases. The increase in survival and life expectancy of these children means that they can continue their clinical care in adult units. The transition from pediatric care must be an active, timely and progressive process. It may be slightly stressful for the patient before the adaptation to this new environment, with multidisciplinary care always being maintained.

Multidisciplinary approach to the management of myopathies

PURPOSE OF REVIEW

Aside from some inflammatory myopathies and very few genetic disorders, there are no therapies that make most patients with myopathies stronger. Consequently, the management of these patients can be frustrating for patients and their families as well as the clinicians taking care of them. Treatment of these patients must involve a comprehensive approach focused on limiting the secondary effects of skeletal muscle weakness, managing comorbidities associated with specific diseases, and, most importantly, optimizing patients' functional abilities and quality of life in terms of their ability to accomplish activities of daily living. While the approach to each patient differs depending on their disease, certain common themes can be addressed in each patient. This review highlights an approach centered on four conceptual themes ("the Four S's"): Strength therapies, Supportive care, Symptomatic therapies, and pSychological support.

RECENT FINDINGS

Although relatively few well-designed studies have been done that highlight conservative management of patients with various myopathies, an emerging literature helps guide the clinician in certain key areas, especially in relation to cardiac and pulmonary management of these patients.

SUMMARY

While disease-altering therapies have proven elusive for many muscle diseases, a multimodal approach to the conservative and supportive care of these patients can markedly improve their quality of life. Pharmacologic treatment options for specific myopathies will not be addressed in this article but are covered elsewhere in this issue of CONTINUUM.

Effects of respiratory muscle training on pulmonary functions in patients with slowly progressive neuromuscular disease: a randomized controlled trial

Objective:

To investigate the effects of inspiratory and expiratory muscle training on pulmonary functions in patients with slowly progressive neuromuscular disease.

Design:

Prospective randomized controlled double-blinded study.

Setting:

Chest diseases clinic of university hospital.

Subjects:

Twenty-six patients with slowly progressive neuromuscular disease followed for respiratory problems were included in the study. Patients were randomly divided into two groups; experimental ( n = 14; age 31.6 ±12.3 years) and sham ( n = 12; age 26.5 ±8.6 years) groups.

Methods:

Spirometry, peak cough flow, maximal inspiratory pressure, maximal expiratory pressure, and sniff nasal inspiratory pressure were measured before the eighth week of study, and subsequently at end of it. Respiratory muscle training was performed by inspiratory (Threshold Inspiratory Muscle Trainer) and expiratory (Threshold Positive Expiratory Pressure) threshold loading methods. Training intensities were increased according to maximal inspiratory and expiratory pressures in the experimental group, while the lowest loads were used for training in the sham group. Patients performed 15 minutes inspiratory muscle training and 15 minutes expiratory muscle training, twice a day, five days/week, for a total of eight weeks at home. Training intensity was adjusted in the training group once a week.

Results:

Maximal inspiratory and expiratory pressures (cmH2O, % predicted) (respectively p = 0.002, p = 0.003, p = 0.04, p = 0.03) and sniff nasal inspiratory pressure ( p = 0.04) were improved in the experimental group when compared with the sham group. However, there was no improvement in spirometric measurements when groups were compared ( p > 0.05).

Conclusions:

As a conclusion of our study, we found that respiratory muscle strength improved by inspiratory and expiratory muscle training in patients with slowly progressive neuromuscular disease.

Management of pulmonary complications in neuromuscular disease

Restrictive lung disease occurs commonly in patients with neuromuscular disease. The earliest sign of respiratory compromise in the patient with neuromuscular disease is nocturnal hypoventilation, which progresses over time to include daytime hypoventilation and eventually the need for full-time mechanical ventilation. Pulmonary function testing should be done during regular follow-up visits to identify the need for assistive respiratory equipment and initiate early noninvasive ventilation. Initiation of noninvasive ventilation can improve quality of life and prolong survival in patients with neuromuscular disease.

Effect of home mechanical in-exsufflation on hospitalisation and life-style in neuromuscular disease: a pilot study

AIM

Mechanical in-exsufflation (MI-E) augments the weakened cough of patients with neuromuscular disease (NMD), clearing secretions and overcoming atelectasis. Little has been published on the impact of MI-E alone on rates of hospitalisation and quality of life (QOL). The aim of this study was to assess the impact of home MI-E on hospital admissions and life-style in children with NMD.

METHODS

A retrospective chart review was performed on children using MI-E, including data on the number of admissions to hospital, length of stay and hours of ventilation. A parental survey was used to gather information on the impact of MI-E on life-style for the child and family.

RESULTS

Ten children with NMD (seven spinal muscular atrophy, two Duchenne muscular dystrophy and one centronuclear myopathy) using MI-E at home were identified. MI-E use commenced at mean age of 8.5 years (range 1.1-16.9) with 1.4 years of use (range 0.3-3.8). MI-E pressures ranged from +/-30 to 40 cmH2 O with no complications reported. There was a significant reduction in hospital days at 6 (P = 0.036) and 12 (P = 0.028) months following commencement of home MI-E compared with the same period preceding MI-E use. The survey highlighted positive benefits of MI-E use, in particular the ability to treat many pulmonary exacerbations at home.

CONCLUSIONS

Home MI-E use by children with NMD can reduce hospitalisation and benefit families by maintaining their child at home.

Respiratory management strategies for Duchenne muscular dystrophy: practice variation amongst Canadian sub-specialists

PURPOSE

Respiratory management of Duchenne muscular dystrophy (DMD) is not well studied and may vary across centers and practitioners. Our objective was to describe and compare the respiratory management practices of Canadian Pediatric Respirologists and Neuromuscular specialists for children with DMD.

METHODS

A web-based survey was sent to all 56 practicing Canadian Pediatric Respirologists and to all 24 members of the Canadian Pediatric Neuromuscular Group (CPNG) who follow children with neuromuscular diseases. The survey included 28 questions about timing and indications for respiratory consultation, sleep disordered breathing (SDB) assessments, and treatments.

RESULTS

Thirty eight (68%) pediatric respirologists and 17 (71%) CPNG members responded. Respirologists provide initial consultation after a patient's first admission to hospital with respiratory complications (14/38, 37%) and when symptoms of SDB are present (14/38, 37%). Half of the CPNG members request initial Respirology consultation at the time of DMD diagnosis. Both groups request routine pulmonary function tests. Ninety-six percent of respirologists use maximal inspiratory (MIP) and expiratory pressures (MEP) to assess respiratory muscle strength, whereas 82% of CPNG members additionally use peak cough flow. Assessment for SDB is requested by both groups when pulmonary function is abnormal or patients are symptomatic. Respirologists favor polysomnography, whereas CPNG members use overnight pulse oximetry. Nocturnal non-invasive ventilation and lung volume recruitment (LVR) are used in a minority of patients.

CONCLUSIONS

Respirologists and CPNG members provide similar respiratory management of DMD patients, but differ in timing of consultation and choice of tests for pulmonary function and SDB. Canadian practices differ from the American Thoracic Society and Centre for Disease Control guidelines.