Physiologic benefits of mechanical insufflation-exsufflation in children with neuromuscular diseases

[Proposals from a French expert panel for respiratory care in ALS patients]

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive diaphragm weakness and deteriorating lung function. Bulbar involvement and cough weakness contribute to respiratory morbidity and mortality. ALS-related respiratory failure significantly affects quality of life and is the leading cause of death. Non-invasive ventilation (NIV), which is the main recognized treatment for alleviating the symptoms of respiratory failure, prolongs survival and improves quality of life. However, the optimal timing for the initiation of NIV is still a matter of debate. NIV is a complex intervention. Multiple factors influence the efficacy of NIV and patient adherence. The aim of this work was to develop practical evidence-based advices to standardize the respiratory care of ALS patients in French tertiary care centres.

METHODS

For each proposal, a French expert panel systematically searched an indexed bibliography and prepared a written literature review that was then shared and discussed. A combined draft was prepared by the chairman for further discussion. All of the proposals were unanimously approved by the expert panel.

RESULTS

The French expert panel updated the criteria for initiating NIV in ALS patients. The most recent criteria were established in 2005. Practical advice for NIV initiation were included and the value of each tool available for NIV monitoring was reviewed. A strategy to optimize NIV parameters was suggested. Revisions were also suggested for the use of mechanically assisted cough devices in ALS patients.

CONCLUSION

Our French expert panel proposes an evidence-based review to update the respiratory care recommendations for ALS patients in daily practice.

The Effect of Pressure Changes During Mechanical Insufflation-Exsufflation on Respiratory and Airway Physiology

BACKGROUND

Respiratory muscle weakness can impair cough function, leading to lower respiratory tract infections. These infections are an important contributor to morbidity and mortality in patients with neuromuscular disease. Mechanical insufflation-exsufflation (MIE) is used to augment cough function in these patients. Although MIE is widely used, there are few data to advise on the optimal technique. Since the introduction of MIE, the recommended pressures to be delivered have increased. There are concerns regarding the use of higher pressures and their potential to cause lung derecruitment and upper airway closure.

RESEARCH QUESTION

What is the impact of high-pressure MIE (HP-MIE) on lung recruitment, respiratory drive, upper airway flow, and patient comfort, compared with low-pressure MIE (LP-MIE), in patients with respiratory muscle weakness?

STUDY DESIGN AND METHODS

Clinically stable patients using domiciliary MIE with respiratory muscle weakness secondary to Duchenne muscle dystrophy, spinal cord injury, or long-term tracheostomy ventilation received LP-MIE (30/-30 cm H2O) and HP-MIE (60/-60 cm H2O) in a random sequence. Lung recruitment, neural respiratory drive, and cough peak expiratory flow were measured throughout, and patients reported comfort and breathlessness following each intervention.

RESULTS

A total of 29 patients (10 with Duchenne muscle dystrophy, eight with spinal cord injury, and 11 with long-term tracheostomy ventilation) were included in this study. HP-MIE augmented cough peak expiratory flow compared with LP-MIE (mean cough peak expiratory flow HP-MIE 228 ± 81 L/min vs LP-MIE 179 ± 67 L/min; P = .0001) without any significant change in lung recruitment, neural respiratory drive, or patient-reported breathlessness. However, in patients with more pronounced respiratory muscle weakness, HP-MIE resulted in an increased rate of upper airway closure and patient discomfort that may have an impact on clinical efficacy.

INTERPRETATION

HP-MIE did not lead to lung derecruitment or breathlessness compared with LP-MIE. However, it was poorly tolerated in individuals with advanced respiratory muscle weakness. HP-MIE generates more upper airway closure than LP-MIE, which may be missed if cough peak expiratory flow is used as the sole titration target.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02753959; URL: www.

CLINICALTRIALS

gov.

Mechanically assisted cough strategies: user perspectives and cough flows in children with neurodisability

Background

Mechanical insufflation-exsufflation (MI-E) is used to augment cough in children with neurodisability. We aimed to determine the user comfort and cough flows during three MI-E strategies, and to predict factors associated with improved comfort and cough flows.

Methods

This multicentre, crossover trial was done at four regional hospitals in Norway. Children with neurodisability using MI-E long term via mask were enrolled. In randomised order, they tested three MI-E setting strategies (in-/exsufflation pressure (cmH2O)/in (In)- versus exsufflation (Ex) time): 1) "A-symmetric" (±50/In=Ex); 2) "B-asymmetric" (+25- +30)/-40, In>Ex); and 3) "C-personalised", as set by their therapist. The primary outcomes were user-reported comfort on a visual analogue scale (VAS) (0=maximum comfort) and peak cough flows (PCF) (L·min-1) measured by a pneumotachograph in the MI-E circuit.

Results

We recruited 74 children median (IQR) age 8.1 (4.4-13.8) years, range 0.6-17.9, and analysed 218 MI-E sequences. The mean±sd VAS comfort scores were 4.7±2.96, 2.9±2.44 and 3.2±2.46 for strategies A, B and C, respectively (A versus B and C, p<0.001). The mean±sd PCF registered during strategies A, B and C were 203±46.87, 166±46.05 and 171±49.74 L·min-1, respectively (A versus B and C, p<0.001). Using low inspiratory flow predicted improved comfort. Age and unassisted cough flows increased exsufflation flows.

Conclusions

An asymmetric or personalised MI-E strategy resulted in better comfort scores, but lower PCF than a symmetric approach utilising high pressures. All three strategies generated cough flows above therapeutic thresholds and were rated as slightly to moderately uncomfortable.

Respiratory Management of Patients With Neuromuscular Weakness: An American College of Chest Physicians Clinical Practice Guideline and Expert Panel Report

BACKGROUND

Respiratory failure is a significant concern in neuromuscular diseases (NMDs). This CHEST guideline examines the literature on the respiratory management of patients with NMD to provide evidence-based recommendations.

STUDY DESIGN AND METHODS

An expert panel conducted a systematic review addressing the respiratory management of NMD and applied the Grading of Recommendations, Assessment, Development, and Evaluations approach for assessing the certainty of the evidence and formulating and grading recommendations. A modified Delphi technique was used to reach a consensus on the recommendations.

RESULTS

Based on 128 studies, the panel generated 15 graded recommendations, one good practice statement, and one consensus-based statement.

INTERPRETATION

Evidence of best practices for respiratory management in NMD is limited and is based primarily on observational data in amyotrophic lateral sclerosis. The panel found that pulmonary function testing every 6 months may be beneficial and may be used to initiate noninvasive ventilation (NIV) when clinically indicated. An individualized approach to NIV settings may benefit patients with chronic respiratory failure and sleep-disordered breathing related to NMD. When resources allow, polysomnography or overnight oximetry can help to guide the initiation of NIV. The panel provided guidelines for mouthpiece ventilation, transition to home mechanical ventilation, salivary secretion management, and airway clearance therapies. The guideline panel emphasizes that NMD pathologic characteristics represent a diverse group of disorders with differing rates of decline in lung function. The clinician's role is to add evaluation at the bedside to shared decision-making with patients and families, including respect for patient preferences and treatment goals, considerations of quality of life, and appropriate use of available resources in decision-making.

Mechanical Insufflation-Exsufflation: Considerations for Improving Clinical Practice

The provision of mechanical insufflation-exsufflation (MI-E) devices to enhance cough efficacy is increasing. Typically, MI-E devices are used to augment cough in patients with neuromuscular disorders but also in patients who are weak in an acute care setting. Despite a growing evidence base for the use of these devices, there are barriers to the provision of MI-E, including clinician lack of knowledge and confidence. Enhancing clinician education and confidence is key. Individualized or protocolized approaches can be used to initiate MI-E. Evaluation of MI-E efficacy is critical. One method to evaluate effectiveness of MI-E is the MI-E-assisted cough peak flow (CPF). However, this should always be considered alongside other factors discussed in this review. The purpose of this review is to increase the theoretical understanding of the provision and evaluation of MI-E and provide insight into how this knowledge can be applied into clinical practice. Approaches to initiation and titration can be selected based on the clinical situation, patient diagnosis (including and beyond neuromuscular disorders), and clinician’s confidence.

Pulmonological issues

Pediatric leukodystrophies are rare neurodegenerative diseases involving multiple systems. Each form has unique neurologic features but are characterized by encephalopathy with accompanying impairments evidenced in reflexes, muscle tone and movement control. Weakness of expiratory, inspiratory, and upper airway muscles may lead to impaired airway secretion clearance resulting in recurrent respiratory infections, dysphagia, sleep-disordered breathing, restrictive lung disease, and ultimately chronic respiratory insufficiency.

Proposals from a French expert panel for respiratory care in ALS patients

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive diaphragm weakness and deteriorating lung function. Bulbar involvement and cough weakness contribute to respiratory morbidity and mortality. ALS-related respiratory failure significantly affects quality of life and is the leading cause of death. Non-invasive ventilation (NIV), which is the main recognized treatment for alleviating the symptoms of respiratory failure, prolongs survival and improves quality of life. However, the optimal timing for the initiation of NIV is still a matter of debate. NIV is a complex intervention. Multiple factors influence the efficacy of NIV and patient adherence. The aim of this work was to develop practical evidence-based advices to standardize the respiratory care of ALS patients in French tertiary care centres.

METHODS

For each proposal, a French expert panel systematically searched an indexed bibliography and prepared a written literature review that was then shared and discussed. A combined draft was prepared by the chairman for further discussion. All of the proposals were unanimously approved by the expert panel.

RESULTS

The French expert panel updated the criteria for initiating NIV in ALS patients. The most recent criteria were established in 2005. Practical advice for NIV initiation were included and the value of each tool available for NIV monitoring was reviewed. A strategy to optimize NIV parameters was suggested. Revisions were also suggested for the use of mechanically assisted cough devices in ALS patients.

CONCLUSION

Our French expert panel proposes an evidence-based review to update the respiratory care recommendations for ALS patients in daily practice.

Routine lung volume recruitment in boys with Duchenne muscular dystrophy: a randomised clinical trial

BACKGROUND

Impaired cough results in airway secretion retention, atelectasis and pneumonia in individuals with Duchenne muscular dystrophy (DMD). Lung volume recruitment (LVR) stacks breaths to inflate the lungs to greater volumes than spontaneous effort. LVR is recommended in DMD clinical care guidelines but is not well studied. We aimed to determine whether twice-daily LVR, compared with standard of care alone, attenuates the decline in FVC at 2 years in boys with DMD.

METHODS

In this multicentre, assessor-blinded, randomised controlled trial, boys with DMD, aged 6-16 years with FVC >30% predicted, were randomised to receive conventional treatment or conventional treatment plus manual LVR twice daily for 2 years. The primary outcome was FVC % predicted at 2 years, adjusted for baseline FVC % predicted, age and ambulatory status. Secondary outcomes included change in chest wall distensibility (maximal insufflation capacity minus FVC) and peak cough flow.

RESULTS

Sixty-six boys (36 in LVR group, 30 in control) were evaluated (median age (IQR): 11.5 years (9.5-13.5), median baseline FVC (IQR): 85% predicted (73-96)). Adjusted mean difference in FVC between groups at 2 years was 1.9% predicted (95% CI -6.9% to 10.7%; p=0.68) in the direction of treatment benefit. We found no differences in secondary outcomes.

CONCLUSION

There was no difference in decline in FVC % predicted with use of twice-daily LVR for boys with DMD and relatively normal lung function. The burden associated with routine LVR may outweigh the benefit. Benefits of LVR to maintain lung health in boys with worse baseline lung function still need to be clarified.

TRIAL REGISTRATION NUMBER

NCT01999075.

Short-term effect of air stacking and mechanical insufflation-exsufflation on lung function in patients with neuromuscular diseases

Air stacking (AS) and mechanical insufflation-exsufflation (MI-E) aim to increase cough efficacy by augmenting inspiratory lung volumes in patients with neuromuscular diseases (NMDs). We studied the short-term effect of AS and MI-E on lung function. We prospectively included NMD patients familiar with daily AS or MI-E use. Studied outcomes were forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and peak expiratory flow (PEF) prior to, immediately after, and up to 2 h after treatment. Paired sample T-test and Wilcoxon signed-rank test was used. Sixty-seven patients participated. We observed increased FVC and FEV₁ immediately after AS with a mean difference of respectively 0.090 L (95% CI 0.045; 0.135, p < .001) and 0.073 L (95% CI 0.017; 0.128, p = .012). Increased FVC immediately after MI-E (mean difference 0.059 L (95% CI 0.010; 0.109, p = .021) persisted 1 hour (mean difference 0.079 L (95% CI 0.034; 0.125, p = .003). The effect of treatment was more pronounced in patients diagnosed with Spinal Muscular Atrophy, compared to patients with Duchenne muscular dystrophy. AS and MI-E improved FVC immediately after treatment, which persisted 1 h after MI-E. There is insufficient evidence that short-lasting increases in FVC would explain the possible beneficial effect of AS and MI-E.

Mechanical Insufflation Exsufflation, Syringomyelia, and Headache

ABSTRACT

Mechanical insufflation exsufflation creates cough flows to clear central airways secretions for patients with ineffective cough flows. At times, patients with even potentially effective spontaneous cough flows can have pain that prevents effective coughing. We describe a patient with Arnold-Chiari syndrome, syringomyelia, and hydrocephalus who had nine episodes of pneumonia through the age of 9 yrs, and cough associated headaches, who upon using mechanical insufflation exsufflation had no subsequent pneumonias for at least the next 17 yrs and no headaches when using it for coughing.

Cough augmentation techniques for people with chronic neuromuscular disorders

BACKGROUND

People with neuromuscular disorders may have a weak, ineffective cough predisposing them to respiratory complications. Cough augmentation techniques aim to improve cough effectiveness and mucous clearance, reduce the frequency and duration of respiratory infections requiring hospital admission, and improve quality of life.

OBJECTIVES

To determine the efficacy and safety of cough augmentation techniques in adults and children with chronic neuromuscular disorders.

SEARCH METHODS

On 13 April 2020, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and ClinicalTrials.gov for randomised controlled trials (RCTs), quasi-RCTs, and randomised cross-over trials.

SELECTION CRITERIA

We included trials of cough augmentation techniques compared to no treatment, alternative techniques, or combinations thereof, in adults and children with chronic neuromuscular disorders.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility, extracted data, and assessed risk of bias. The primary outcomes were the number and duration of unscheduled hospitalisations for acute respiratory exacerbations. We assessed the certainty of evidence using GRADE.

MAIN RESULTS

The review included 11 studies involving 287 adults and children, aged three to 73 years. Inadequately reported cross-over studies and the limited additional information provided by authors severely restricted the number of analyses that could be performed. Studies compared manually assisted cough, mechanical insufflation, manual and mechanical breathstacking, mechanical insufflation-exsufflation, glossopharyngeal breathing, and combination techniques to unassisted cough and alternative or sham interventions. None of the included studies reported on the primary outcomes of this review (number and duration of unscheduled hospital admissions) or listed 'adverse events' as primary or secondary outcome measures. The evidence suggests that a range of cough augmentation techniques may increase peak cough flow compared to unassisted cough (199 participants, 8 RCTs), but the evidence is very uncertain. There may be little to no difference in peak cough flow outcomes between alternative cough augmentation techniques (216 participants, 9 RCTs). There was insufficient evidence to determine the effect of interventions on measures of gaseous exchange, pulmonary function, quality of life, general function, or participant preference and satisfaction.

AUTHORS' CONCLUSIONS

We are very uncertain about the safety and efficacy of cough augmentation techniques in adults and children with chronic neuromuscular disorders and further studies are needed.

Pulmonary function testing in patients with neuromuscular disease

Progressive neuromuscular disease leads to muscle weakness or failure that produces loss of pulmonary function and clinical respiratory morbidity. Tracking pulmonary function in a practical and effective way is very important because it can help identify a stage of disease when a morbidity, such as inadequate airway clearance or respiratory failure, may be present. There are four general categories of pulmonary function outcome measures such as volume, flow, pressure, and gas exchange. These outcome measures have variable precision and accuracy in predicting clinical change, and practicality in performing them relative to age and condition. It is widely recommended to follow multiple measurements longitudinally and create an accurate and timely clinical picture. This manuscript will review the most commonly used and most practical measures for use in clinical practice and how they can help to assess morbidity, disease state, and help optimize patient management.

Airway Clearance Techniques: The Right Choice for the Right Patient

The management of bronchial secretions is one of the main problems encountered in a wide spectrum of medical conditions ranging from respiratory disorders, neuromuscular disorders and patients undergoing either thoracic or abdominal surgery. The purpose of this review is illustrate to the reader the different ACTs currently available and the related evidence present in literature. Alongside methods with a strong background behind as postural drainage, manual techniques or PEP systems, the current orientation is increasingly aimed at devices that can mobilize and / or remove secretions. Cough Assist, Vacuum Techniques, systems that modulate airflow have more and more scientific evidence. Different principles combination is a new field of investigation that goes toward an increasing of clinical complexity that will facing us.

Respiratory management of children with spinal muscular atrophy (SMA)

Spinal muscular atrophy (SMA) causes a predominantly bilateral proximal muscle weakness and atrophy. The respiratory muscles are also involved with a weakness of the intercostal muscles and a relatively spared diaphragm. This respiratory muscle weakness translates into a cough impairment, resulting in poor clearance of airway secretions and recurrent pulmonary infections, restrictive lung disease due to a poor or insufficient chest wall and lung growth, nocturnal hypoventilation and, finally, respiratory failure. Systematic and regular monitoring of respiratory muscle performance is necessary in children with SMA in order to anticipate respiratory complications, such as acute and chronic respiratory failure, and guide clinical care. This monitoring is based in clinical practice on volitional and noninvasive tests, such as vital capacity, sniff nasal inspiratory pressure, maximal static pressures, peak expiratory flow and peak cough flow because of their simplicity, availability and ease. In young children, those with poor cooperation or severe respiratory muscle weakness, other, mostly invasive, tests may be required to evaluate respiratory muscle performance. A sleep study, or at least overnight monitoring of nocturnal gas exchange is mandatory for detecting nocturnal alveolar hypoventilation. Training for patients and caregivers in cough-assisted techniques is recommended when respiratory muscle strength falls below 50% of predicted or in case of recurrent or severe respiratory infections. Noninvasive ventilation (NIV) should be initiated in case of isolated nocturnal hypoventilation and followed by a pediatric respiratory team with expertise in NIV. Multidisciplinary (neurology and respiratory) pediatric management is crucial for optimal care of children with SMA. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Randomized trial of lung hyperinflation therapy in children with congenital muscular dystrophy

OBJECTIVE

Respiratory compromise in congenital muscular dystrophy (CMD) occurs, in part, from chest wall contractures. Passive stretch with hyperinsufflation therapy could reduce related costo-vertebral joint contractures. We sought to examine the impact of hyperinsufflation use on lung function and quality of life in children with CMD.

STUDY DESIGN

We conducted a randomized controlled trial on hyperinsufflation therapy in children with CMD at two centers. An individualized hyperinsufflation regimen of 15 minutes twice daily using a cough assist device over a 12 months period was prescribed. We measured lung function, quality of life, and adherence. To demonstrate reproducibility, pulmonary function was measured twice on the same day. A mixed-effects regression model adjusting for confounders was used to assess the effects of hyperinsufflation.

RESULTS

We enrolled 34 participants in the study; 31 completed the trial (n = 17 treatment group and n = 14 controls). Participants in the treatment group demonstrated a relative gain in lung volume measured at 4 and 8 months, but not at 12 months. The control group required increases in the maximum insufflation pressures to achieve maximum lung volumes while the treatment group did not. Adherence was best early in the study, peaking at the first visit and decreasing at subsequent visits. Caregiver-reported quality of life was higher in the treatment group.

CONCLUSION

Hyperinsufflation therapy is effective in increasing and sustaining lung volume over time. Adherence, however, was inconsistent and difficult to maintain. Further research should determine if improved adherence leads to sustained benefits of hyperinsufflation.

A Review on Cough Augmentation Techniques: Assisted Inspiration, Assisted Expiration and Their Combination

Cough is an important mechanism of airway clearance. In patients who present weak and ineffective cough, augmentation techniques aim to assist or simulate the maneuver. These techniques target different phases of the cough cycle, mainly the inspiratory and expiratory phases, through assisted inspiration, assisted expiration and their combination. They include the manual hyperinflation, ventilator hyperinflation, glossopharyngeal breathing, manually assisted cough and mechanical insufflator-exsufflator, each applied individually or in different combinations. The aim of this review is to investigate the effectiveness and safety of cough augmentation techniques. Findings support that all commonly used techniques can theoretically improve airway clearance, as they generate higher cough peak flows compared to unassisted cough. Still, the studies assessing cough augmentation present considerable limitations and the direct comparison of different techniques is challenging. Current evidence indicate that cough peak flow shows higher increase with the combination of assisted inspiration and expiration, and improvement is greater in patients with lower unassisted values. Associated adverse events are infrequent.

Optimizing expiratory flows during mechanical cough in a pediatric neuromuscular lung model

Mechanical insufflation-exsufflation (MI-E) is recommended for subjects of all ages with neuromuscular disorders (NMDs) and weak cough. There is a lack of knowledge on the optimal treatment settings for young children. This study aims to determine the MI-E settings providing high expiratory airflow while using safe inspiratory volumes, and to identify possible limits where the benefit of incrementing the MI-E settings to achieve a higher expiratory airflow, decreased. Using an MI-E device and a lung model imitating a 1-year-old child with NMD, we explored the impact of 120 combinations of MI-E pressure and time settings on maximal expiratory airflow and inspiratory volume. High expiratory airflows were achieved with several pressure and time combinations where the exsufflation pressure, followed by insufflation pressure and time, had the greatest impact. The benefit of incrementing the settings to increase the expiratory airflow leveled off for the insufflation pressure and time, but not for the exsufflation pressure. Given exsufflation pressure of -40 or -50 cmH₂ O and insufflation time longer than 1 second, a plateau in the expiratory airflow curve was present at insufflation pressures from 25 cmH₂ O, whereas a plateau in the inspired volume curve occurred at insufflation pressures from 35 cmH₂ O. The present neuromuscular pediatric lung model study showed that expiratory pressure impacts expiratory airflow more than inspiratory pressure and time. An inspiratory and expiratory pressure set between 20 to 30 and -40 cmH₂ O, respectively, and an inspiratory time longer than 1 second may be considered as a basis when titrating MI-E settings in young children with NMD. The findings must be confirmed in clinical trials.

Preliminary Effectiveness and Safety of High Frequency Oscillation in Addition to Mechanical Insufflation and Exsufflation for Intratracheal Mucus Removal in Patients With Neuromuscular Disease: Protocol for a Prospective Study

Background

Mechanical insufflation-exsufflation (MI-E) is necessary for noninvasive management of respiratory clearance in patients with neuromuscular disorders (NMDs). Its utility has been proven, and the technique is recommended in a number of international guidelines for the management of patients with NMDs. However, the clearance of thick secretions adhering to the tracheobronchial walls could be problematic when these patients suffer from respiratory tract infections. To improve the effectiveness of the noninvasive technique, a novel device combining MI-E with high frequency oscillation (HFO) has been developed. However, the efficacy of HFO therapy in NMDs has not been well studied.

Objective

The aim of this study was to elucidate the effect of MI-E combined with HFO for mucus removal in NMD patients. To evaluate its efficacy, changes in transcutaneous oxygen saturation (SpO₂), which may predict intratracheal mucus removal, will be measured before and after use of MI-E.

Methods

This is a single-center, nonblinded, nonrandomized prospective study that will enroll 5 subjects hospitalized in Kobe University Hospital owing to respiratory tract infection. All subjects will receive MI-E therapy a few times daily and will receive HFO every other day, for 6 days. Before and after MI-E use, SpO₂ will be obtained and the change in SpO₂ (ΔSpO₂) between MI-E with and without HFO will be calculated. For every subject, the average of ΔSpO₂ with or without HFO will be obtained and the null hypothesis that there is a mean change of 0 in the SpO₂ between MI-E with and without HFO will be tested using the paired t test. If the treatment with HFO is found to be statistically significantly superior to the treatment without HFO, the study will conclude that HFO addition is more efficacious than no HFO addition.

Results

A total of 2 subjects have already been recruited and enrolled in this study as of August 2018.

Conclusions

This unique protocol will assess the efficacy of adding HFO to MI-E during the acute phase of respiratory tract infection in patients with NMDs.

International Registered Report Identifier (IRRID)

DERR1-10.2196/12102

Mechanical insufflation/exsufflation improves respiratory mechanics in critical care: Randomized crossover trial

This study evaluated the ventilatory and haemodynamic effects of the mechanical insufflator-exsufflator (MI-E) in critically ill patients. Sixteen mechanically ventilated patients performed three protocols: MI-E (-30/+30 cmH₂O) plus endotracheal suctioning; 50S: MI-E (-50/+50 cmH2O) plus endotracheal suctioning; and isolated endotracheal suctioning (IES). The protocols were applied randomly in all subjects, with 3 -h intervals in between. Peak airway pressure (Ppeak), plateau pressure (Pplat), airway resistance (Raw), static compliance (Cst), heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure, peripheral oxygen saturation (SpO₂) and amount of removed secretions were evaluated before (PRE), immediately after (POST) and 10 min after (10' POST) each protocol. The 50S protocol reduced Ppeak and Raw and increased Cst immediately after its application. Moreover, this protocol provided the largest amount of removed secretions and held SBP, DBP and SpO₂ at basal values. The MI-E at high pressures promotes benefits to respiratory mechanics, is more effective in removing pulmonary secretions and it does not lead to hemodynamic repercussions.

Titration of Mechanical Insufflation-Exsufflation Optimal Pressure Combinations in Neuromuscular Diseases by Flow/Pressure Waveform Analysis

INTRODUCTION

The aim of this study was to assess several air-pressure settings for MI-E to determine their effect on peak cough flow (PCF), and to compare the best pressures with those are more common used in the literature (±40cmH₂O) in patients with neuromuscular disorders (NMD).

METHODS

Adults with NMD in whom MI-E was indicated were recruited. Assisted PCF was measured by an external pneumotachograph. The protocol included 9 PCF measures per patient: 1 baseline (non-assisted), 4 with increasing inspiratory pressures without negative pressure (10, 20, 30 and 40cmH₂O or maximum tolerated), and then 4 adding expiratory pressures (-10, -20, -30 and -40cmH₂O or maximum tolerated) with maximum inspiratory pressure previously achieved.

RESULTS

Twenty one patients were included, 61% with amyotrophic lateral sclerosis (ALS). Mean PCFs with recommended pressures (±40cmH₂O) were lower than the scored in the individualized steps of the titration protocol (197.7±67l/min vs 214.2±60l/min, p<0.05). Regarding subgroups, mean PCF_max values in ALS patients with bulbar symptoms were significantly higher than those achieved with recommended pressures (163.6±80 vs 189±66l/min, p<0.05).

CONCLUSION

The PCF_max obtained with the protocol did not always match the recommended settings. It may be advisable to perform MI-E titration assessed by non-invasive PCF monitoring in patients with NMD, especially in ALS with bulbar involvement to improve the therapy detecting airway collapse induced by high pressures.

Improvement of Peak Cough Flow After the Application of a Mechanical In-exsufflator in Patients With Neuromuscular Disease and Pneumonia: A Pilot Study

Objective

To investigate and demonstrate persistent increase of peak cough flow after mechanical in-exsufflator application, in patients with neuromuscular diseases and pneumonia.

Methods

A mechanical in-exsufflator was applied with patients in an upright or semi-upright sitting position (pressure setting, +40 and −40 cmH₂O; in-exsufflation times, 2–3 and 1–2 seconds, respectively). Patients underwent five cycles, with 20–30 second intervals to prevent hyperventilation. Peak cough flow without and with assistive maneuvers, was evaluated before, and 15 and 45 minutes after mechanical in-exsufflator application.

Results

Peak cough flow was 92.6 L/min at baseline, and 100.4 and 100.7 L/min at 15 and 45 minutes after mechanical in-exsufflator application, respectively. Assisted peak cough flow at baseline, 15 minutes, and 45 minutes after mechanical in-exsufflator application was 170.7, 179.3, and 184.1 L/min, respectively. While peak cough flow and assisted peak cough flow increased significantly at 15 minutes after mechanical in-exsufflator application compared with baseline (p=0.030 and p=0.016), no statistical difference was observed between 15 and 45 minutes.

Conclusion

Increased peak cough flow after mechanical in-exsufflator application persists for at least 45 minutes.

Respiratory Management of the Patient With Duchenne Muscular Dystrophy

In 2010, Care Considerations for Duchenne Muscular Dystrophy, sponsored by the Centers for Disease Control and Prevention, was published in Lancet Neurology, and in 2018, these guidelines were updated. Since the publication of the first set of guidelines, survival of individuals with Duchenne muscular dystrophy has increased. With contemporary medical management, survival often extends into the fourth decade of life and beyond. Effective transition of respiratory care from pediatric to adult medicine is vital to optimize patient safety, prognosis, and quality of life. With genetic and other emerging drug therapies in development, standardization of care is necessary to accurately assess treatment effects in clinical trials. This revision of respiratory recommendations preserves a fundamental strength of the original guidelines: namely, reliance on a limited number of respiratory tests to guide patient assessment and management. A progressive therapeutic strategy is presented that includes lung volume recruitment, assisted coughing, and assisted ventilation (initially nocturnally, with the subsequent addition of daytime ventilation for progressive respiratory failure). This revision also stresses the need for serial monitoring of respiratory muscle strength to characterize an individual's respiratory phenotype of severity as well as provide baseline assessments for clinical trials. Clinical controversies and emerging areas are included.

The clinical use of mechanical insufflation-exsufflation in children with neuromuscular disorders in Europe

Mechanical insufflation-exsufflation (MI-E) is a strategy to treat pulmonary exacerbations in neuromuscular disorders (NMDs). Pediatric guidelines for optimal setting titration of MI-E are lacking and the settings used in studies vary. Our objective was to assess the actual MI-E settings being used in current clinical treatment of children with NMDs and a survey was sent in July 2016 to European expertise centers. Ten centers from seven countries gave information on MI-E settings for 240 children aged 4 months to 17.8 years (mean 10.5). Settings varied greatly between the centers. Auto mode was used in 71%, triggering of insufflation in 21% and manual mode in 8% of the cases. Mean (SD) time for insufflation (Ti) and exsufflation (Te) were 1.9 (0.5) and 1.8 (0.6) s respectively, both ranging from 1 to 4s. Asymmetric time settings were common (65%). Mean (SD) insufflation (Pi) and exsufflation (Pe) pressures were 32.4 (7.8) and -36.9 (7.4), ranging 10 to 50 and -10 to -60cmH₂O, respectively. Asymmetric pressures were as common as symmetric. Both Ti, Te, Pi and Pe increased with age (p < 0.001). In conclusion, pediatric MI-E settings in clinical use varied greatly and altered with age, highlighting the need of more studies to improve our knowledge of optimal settings in MI-E in children with NMDs.

Airway clearance techniques in neuromuscular disorders: A state of the art review

This is a unique state of the art review written by a group of 21 international recognized experts in the field that gathered during a meeting organized by the European Neuromuscular Centre (ENMC) in Naarden, March 2017. It systematically reports the entire evidence base for airway clearance techniques (ACTs) in both adults and children with neuromuscular disorders (NMD). We not only report randomised controlled trials, which in other systematic reviews conclude that there is a lack of evidence base to give an opinion, but also include case series and retrospective reviews of practice. For this review, we have classified ACTs as either proximal (cough augmentation) or peripheral (secretion mobilization). The review presents descriptions; standard definitions; the supporting evidence for and limitations of proximal and peripheral ACTs that are used in patients with NMD; as well as providing recommendations for objective measurements of efficacy, specifically for proximal ACTs. This state of the art review also highlights how ACTs may be adapted or modified for specific contexts (e.g. in people with bulbar insufficiency; children and infants) and recommends when and how each technique should be applied.

Recommendations for mechanical ventilation of critically ill children from the Paediatric Mechanical Ventilation Consensus Conference (PEMVECC)

Purpose

Much of the common practice in paediatric mechanical ventilation is based on personal experiences and what paediatric critical care practitioners have adopted from adult and neonatal experience. This presents a barrier to planning and interpretation of clinical trials on the use of specific and targeted interventions. We aim to establish a European consensus guideline on mechanical ventilation of critically children.

Methods

The European Society for Paediatric and Neonatal Intensive Care initiated a consensus conference of international European experts in paediatric mechanical ventilation to provide recommendations using the Research and Development/University of California, Los Angeles, appropriateness method. An electronic literature search in PubMed and EMBASE was performed using a combination of medical subject heading terms and text words related to mechanical ventilation and disease-specific terms.

Results

The Paediatric Mechanical Ventilation Consensus Conference (PEMVECC) consisted of a panel of 15 experts who developed and voted on 152 recommendations related to the following topics: (1) general recommendations, (2) monitoring, (3) targets of oxygenation and ventilation, (4) supportive measures, (5) weaning and extubation readiness, (6) normal lungs, (7) obstructive diseases, (8) restrictive diseases, (9) mixed diseases, (10) chronically ventilated patients, (11) cardiac patients and (12) lung hypoplasia syndromes. There were 142 (93.4%) recommendations with “strong agreement”. The final iteration of the recommendations had none with equipoise or disagreement.

Conclusions

These recommendations should help to harmonise the approach to paediatric mechanical ventilation and can be proposed as a standard-of-care applicable in daily clinical practice and clinical research.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-017-4920-z) contains supplementary material, which is available to authorized users.

Respiratory Care Considerations for Children with Medical Complexity

Children with medical complexity (CMC) are a growing population of diagnostically heterogeneous children characterized by chronic conditions affecting multiple organ systems, the use of medical technology at home as well as intensive healthcare service utilization. Many of these children will experience either a respiratory-related complication and/or they will become established on respiratory technology at home during their care trajectory. Therefore, healthcare providers need to be familiar with the respiratory related complications commonly experienced by CMC as well as the indications, technical and safety considerations and potential complications that may arise when caring for CMC using respiratory technology at home. This review will outline the most common respiratory disease manifestations experienced by CMC, and discuss various respiratory-related treatment options that can be considered, including tracheostomy, invasive and non-invasive ventilation, as well as airway clearance techniques. The caregiver requirements associated with caring for CMC using respiratory technology at home will also be reviewed.

[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.

Spontaneous Breathing Pattern as Respiratory Functional Outcome in Children with Spinal Muscular Atrophy (SMA)

Introduction

SMA is characterised by progressive motor and respiratory muscle weakness. We aimed to verify if in SMA children 1)each form is characterized by specific ventilatory and thoraco-abdominal pattern(VTAp) during quiet breathing(QB); 2)VTAp is affected by salbutamol therapy, currently suggested as standard treatment, or by the natural history(NH) of SMA; 3)the severity of global motor impairment linearly correlates with VTAp.

Materials and methods

VTAp was analysed on 32 SMA type I (SMA1,the most severe form), 51 type II (SMA2,the moderate), 8 type III (SMA3,the mildest) and 20 healthy (HC) using opto-electronic plethysmography. Spirometry, cough and motor function were measured in a subgroup of patients.

Results

In SMA1, a normal ventilation is obtained in supine position by rapid and shallow breathing with paradoxical ribcage motion. In SMA2, ventilation is within a normal range in seated position due to an increased respiratory rate(p<0.05) with reduced tidal volume(p<0.05) secondary to a poor contribution of pulmonary ribcage(%ΔV_RC,P, p<0.001). Salbutamol therapy had no effect on VTAp during QB(p>0.05) while tachypnea occurred in type I NH. A linear correlation(p<0.001) was found between motor function scales and VTAp.

Conclusion

A negative or reduced %ΔV_RC,P, indicative of ribcage muscle weakness, is a distinctive feature of SMA1 and SMA2 since infancy. Its quantitative assessment represents a non-invasive, non-volitional index that can be obtained in all children, even uncollaborative, and provides useful information on the action of ribcage muscles that are known to be affected by the disease.Low values of motor function scales indicate impairment of motor but also of respiratory function.

Respiratory management of patients with Fukuyama congenital muscular dystrophy

BACKGROUND

Fukuyama congenital muscular dystrophy (FCMD), characterized by intellectual impairment associated with cortical migration defects, is an autosomal recessive disorder caused by mutation in the fukutin gene. It is the second most common type of muscular dystrophy in Japan. Respiratory dysfunction, along with cardiomyopathy, can be life-threatening in patients with advanced-stage FCMD. However, few reports have focused on this issue.

METHODS

We retrospectively studied respiratory dysfunction and therapeutic management in 48 genetically diagnosed FCMD patients (mean age 11.0 years; range 3.6-31.9 years).

RESULTS

Mechanical ventilation was initiated at a median age of 12.1 years in 16 patients, 14 of whom received non-invasive positive pressure ventilation (NPPV) while the other 2 underwent tracheostomy with invasive ventilation (TIV). The two TIV cases had unexpectedly required the initiation of ventilatory support at the ages of 15.7 and 18.0 years, respectively, because of unsuccessful extubation followed by serious respiratory infections, despite rather good respiratory function before these episodes. Patients carrying a compound heterozygous founder mutation or with a severe phenotype tended to need ventilatory support 2-3 years earlier than homozygous patients and those with the typical or mild phenotype. Mechanical insufflation-exsufflation (MI-E) interventions were also employed in six patients with serious dysphagia and were well-tolerated in all cases.

CONCLUSION

For respiratory management, it is important to regularly evaluate respiratory function in FCMD patients over 10 years of age, since intellectual impairment and insomnia often mask the signs of respiratory dysfunction. Most patients, despite poor cooperation due to intellectual impairment, can tolerate NPPV and MI-E provided that a carefully worked-out plan is adopted.

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.

Mechanical insufflation/exsufflation improves vital capacity in neuromuscular disorders

Inherited neuromuscular disorders inevitably result in severe lung volume restriction associated with high morbidity and mortality. The aim of this retrospective study was to evaluate the long-term effects of the regular use of mechanical insufflation/exsufflation on the course of the vital capacity. This retrospective data analysis included 21 patients (16.1 ± 6.5 years) with neuromuscular disorders and severe lung volume restriction using nocturnal noninvasive ventilation. The patients were advised to regularly use the mechanical insufflation/exsufflation twice a day for 10 minutes applying sets of three insufflation/exsufflation breath via face mask irrespective of respiratory tract infection. Data on the course of vital capacity were collected 2 years prior and 2 years after the introduction of regular use of mechanical insufflation/exsufflation. Before the introduction of mechanical insufflation/exsufflation vital capacity decreased from 0.71 ± 0.38 L to 0.50 ± 0.24 L in the last year and from 0.88 ± 0.45 L to 0.71 ± 0.38 L in the next to last year. In the first year, after regular use of mechanical insufflation/exsufflation vital capacity significantly increased by 28% (from 0.50 L to 0.64 L)—after the second year the vital capacity increase remained stable (0.64 vs. 0.65 L). These data suggest that the regular use of mechanical insufflation/exsufflation improves vital capacity in patients with neuromuscular disorders and severe lung volume restriction.

Non-pharmaceutical management of respiratory morbidity in children with severe global developmental delay

BACKGROUND

Children with severe global developmental delay (SGDD) have significant intellectual disability and severe motor impairment; they are extremely limited in their functional movement and are dependent upon others for all activities of daily living. SGDD does not directly cause lung dysfunction, but the combination of immobility, weakness, skeletal deformity and parenchymal damage from aspiration can lead to significant prevalence of respiratory illness. Respiratory pathology is a significant cause of morbidity and mortality for children with SGDD; it can result in frequent hospital admissions and impacts upon quality of life. Although many treatment approaches are available, there currently exists no comprehensive review of the literature to inform best practice. A broad range of treatment options exist; to focus the scope of this review and allow in-depth analysis, we have excluded pharmaceutical interventions.

OBJECTIVES

To assess the effects of non-pharmaceutical treatment modalities for the management of respiratory morbidity in children with severe global developmental delay.

SEARCH METHODS

We conducted comprehensive searches of the following databases from inception to November 2013: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the Allied and Complementary Medicine Database (AMED) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We searched the Web of Science and clinical trials registries for grey literature and for planned, ongoing and unpublished trials. We checked the reference lists of all primary included studies for additional relevant references.

SELECTION CRITERIA

Randomised controlled trials, controlled trials and cohort studies of children up to 18 years of age with a diagnosis of severe neurological impairment and respiratory morbidity were included. Studies of airways clearance techniques, suction, assisted coughing, non-invasive ventilation, tracheostomy and postural management were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by The Cochrane Collaboration. As the result of heterogeneity, we could not perform meta-analysis. We have therefore presented our results using a narrative approach.

MAIN RESULTS

Fifteen studies were included in the review. Studies included children with a range of severe neurological impairments in differing settings, for example, home and critical care. Several different treatment modalities were assessed, and a wide range of outcome measures were used. Most studies used a non-randomised design and included small sample groups. Only four randomised controlled trials were identified. Non-randomised design, lack of information about how participants were selected and who completed outcome measures and incomplete reporting led to high or unclear risk of bias in many studies. Results from low-quality studies suggest that use of non-invasive ventilation, mechanically assisted coughing, high-frequency chest wall oscillation (HFCWO), positive expiratory pressure and supportive seating may confer potential benefits. No serious adverse effects were reported for ventilatory support or airway clearance interventions other than one incident in a clinically unstable child following mechanically assisted coughing. Night-time positioning equipment and spinal bracing were shown to have a potentially negative effect for some participants. However, these findings must be considered as tentative and require testing in future randomised trials.

AUTHORS' CONCLUSIONS

This review found no high-quality evidence for any single intervention for the management of respiratory morbidity in children with severe global developmental delay. Our search yielded data on a wide range of interventions of interest. Significant differences in study design and in outcome measures precluded the possibility of meta-analysis. No conclusions on efficacy or safety of interventions for respiratory morbidity in children with severe global developmental delay can be made based upon the findings of this review.A co-ordinated approach to future research is vital to ensure that high-quality evidence becomes available to guide treatment for this vulnerable patient group.

Respiratory assessment in centronuclear myopathies

The centronuclear myopathies (CNMs) are a group of inherited neuromuscular disorders classified as congenital myopathies. While several causative genes have been identified, some patients do not harbor any of the currently known mutations. These diverse disorders have common histological features, which include a high proportion of centrally nucleated muscle fibers, and clinical attributes of muscle weakness and respiratory insufficiency. Respiratory problems in CNMs may manifest initially during sleep, but daytime symptoms, ineffective airway clearance, and hypoventilation predominate as more severe respiratory muscle dysfunction evolves. Respiratory muscle capacity can be evaluated using a variety of clinical tests selected with consideration for the age and baseline motor function of the patient. Similar clinical tests of respiratory function can also be incorporated into preclinical CNM canine models to offer insight for clinical trials. Because respiratory problems account for significant morbidity in patients, routine assessments of respiratory muscle function are discussed.

Combined noninvasive ventilation and mechanical in-exsufflator in the treatment of pediatric acute neuromuscular respiratory failure

OBJECTIVES

The present study aims to evaluate the efficacy and complications of combined noninvasive ventilation (NIV) and assisted coughing by mechanical in-exsufflator (MIE) for acute respiratory failure (ARF) in children with neuromuscular disease (NMD).

METHODS

A prospective study was conducted in the pediatric intensive care unit. Children with NMD and ARF treated by combined NIV and MIE were included. Treatment success was defined as freedom from tracheal intubation during the hospital stay. Physiologic indices including PaO2 , PaCO2 , pH, and PaO2 /FiO2 were recorded before and 12, 24 hr after the use of NIV/MIE.

RESULTS

Combined NIV/MIE was used in 15 NMD children (mean: 8.1 years, range: 3 months to 18 years) with 16 cases of ARF. There was no mortality in this cohort. Treatment success was achieved in 12 cases (75%), including six cases (38%) demanding "Do Not Intubate." ARF was due to pneumonia, with a mean baseline PaCO2 of 73.2 ± 19.0 mmHg. In the success group, hypercarbia and acidosis improved after use of NIV/MIE for 24 hr (PaCO2 : 71.7 ± 18.6 mmHg vs. 55.8 ± 11.6 mmHg, P < 0.01; pH: 7.29 ± 0.07 vs. 7.38 ± 0.05, P < 0.01). All patients tolerated NIV/MIE well despite transient skin pressure sores in five cases.

CONCLUSIONS

Combined NIV/MIE is a safe and effective approach to rapidly improve physiologic indices and decrease the need for intubation in NMD children with ARF. NIV/MIE provides a good alternative for those refusing intubation.

Diaphragm remodeling and compensatory respiratory mechanics in a canine model of Duchenne muscular dystrophy

Ventilatory insufficiency remains the leading cause of death and late stage morbidity in Duchenne muscular dystrophy (DMD). To address critical gaps in our knowledge of the pathobiology of respiratory functional decline, we used an integrative approach to study respiratory mechanics in a translational model of DMD. In studies of individual dogs with the Golden Retriever muscular dystrophy (GRMD) mutation, we found evidence of rapidly progressive loss of ventilatory capacity in association with dramatic morphometric remodeling of the diaphragm. Within the first year of life, the mechanics of breathing at rest, and especially during pharmacological stimulation of respiratory control pathways in the carotid bodies, shift such that the primary role of the diaphragm becomes the passive elastic storage of energy transferred from abdominal wall muscles, thereby permitting the expiratory musculature to share in the generation of inspiratory pressure and flow. In the diaphragm, this physiological shift is associated with the loss of sarcomeres in series (∼ 60%) and an increase in muscle stiffness (∼ 900%) compared with those of the nondystrophic diaphragm, as studied during perfusion ex vivo. In addition to providing much needed endpoint measures for assessing the efficacy of therapeutics, we expect these findings to be a starting point for a more precise understanding of respiratory failure in DMD.

Mechanical insufflation-exsufflation for people with neuromuscular disorders

BACKGROUND

People with neuromuscular disorders (NMDs) may have weak respiratory (breathing) muscles which makes it difficult for them to effectively cough and clear mucus from the lungs. This places them at risk of recurrent chest infections and chronic lung disease. Mechanical insufflation-exsufflation (MI-E) is one of a number of techniques available to improve cough efficacy and mucus clearance.

OBJECTIVES

To determine the efficacy and safety of MI-E in people with NMDs.

SEARCH METHODS

On 7 October 2013, we searched the following databases from inception: the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (The Cochrane Library), MEDLINE, and EMBASE. We also searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform for ongoing trials. We conducted handsearches of reference lists and conference proceedings.

SELECTION CRITERIA

We considered randomised or quasi-randomised clinical trials, and randomised cross-over trials of MI-E used to assist airway clearance in people with a NMD and respiratory insufficiency. We considered comparisons of MI-E with no treatment, or alternative cough augmentation techniques.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility, extracted data, and assessed risk of bias in included studies according to standard Cochrane methodology. The primary outcome was mortality throughout follow-up or at six months follow-up.

MAIN RESULTS

Five studies with a total of 105 participants were found to be eligible for inclusion in this review. All included trials were short-term studies (two days or less), measuring immediate effects of the interventions. There was insufficient detail in the reports to assess methods of randomisation and allocation concealment. All five studies were at a high risk of bias from lack of blinding. The studies did not report on mortality, morbidity, quality of life, serious adverse events or any of the other prespecified outcomes. One study was a randomised cross-over trial conducted over two days, in which investigators applied two interventions twice daily in randomly assigned order, with a reverse cross-over the following day. Four studies applied multiple interventions for cough augmentation to each participant, in random order. One study reported fatigue as an adverse effect of MI-E, using a visual analogue scale. Peak cough expiratory flow (PCEF) was the most common outcome measure and was reported in four studies. Based on three studies, MI-E may improve PCEF compared to an unassisted cough. All interventions increased PCEF to the critical level necessary for mucus clearance. The included studies did not clearly show that MI-E improves cough expiratory flow more than other cough augmentation techniques. Based on one study, which was at risk of assessor bias, the addition of MI-E may reduce treatment time when added to a standard airway clearance regimen with manually assisted cough. MI-E appeared to be as well tolerated as other cough augmentation techniques, based on three studies which reported comfort visual analogue scores.

AUTHORS' CONCLUSIONS

The results of this review do not provide sufficient evidence on which to base clinical practice as we were unable to address important short- and long-term outcomes, including adverse effects of MI-E. There is currently insufficient evidence for or against the use of MI-E in people with NMDs. Further randomised controlled clinical trials are needed to test the safety and efficacy of MI-E.

Pulmonary issues in patients with chronic neuromuscular disease

Patients with chronic neuromuscular diseases such as spinal cord injury, amyotrophic lateral sclerosis, and muscular dystrophies experience respiratory complications that are cared for by the respiratory practitioner. An organized anatomical approach for evaluation and treatment is helpful to provide appropriate clinical care. Effective noninvasive strategies for management of hypoventilation, sleep-disordered breathing, and cough insufficiency are available for these patients.

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.

Survival of patients with spinal muscular atrophy type 1

BACKGROUND

Spinal muscular atrophy type 1 (SMA1) is a progressive disease and is usually fatal in the first year of life.

METHODS

A retrospective chart review was performed of SMA1 patients and their outcomes according to the following choices: letting nature take its course (NT); tracheostomy and invasive mechanical ventilation (TV); continuous noninvasive respiratory muscle aid (NRA), including noninvasive ventilation; and mechanically assisted cough.

RESULTS

Of 194 consecutively referred patients enrolled in this study (103 males, 91 females), NT, TV, and NRA were chosen for 121 (62.3%), 42 (21.7%), and 31 (16%) patients, respectively. Survival at ages 24 and 48 months was higher in TV than NRA users: 95% (95% confidence interval: 81.8%-98.8%) and 67.7% (95% confidence interval: 46.7%-82%) at age 24 months (P < .001) and 89.43% and 45% at age 48 months in the TV and NRA groups, respectively (P < .001). The choice of TV decreased from 50% (1992-1998) to 12.7% (2005-2010) (P < .005) with a nonstatistically significant increase for NT from 50% to 65%. The choice of NRA increased from 8.1% (1999-2004) to 22.7% (2005-2010) (P < .001).

CONCLUSIONS

Long-term survival outcome is determined by the choice of the treatment. NRA and TV can prolong survival, with NRA showing a lower survival probability at ages 24 and 48 months.

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.

Neuromuscular scoliosis

Scoliosis is a common deformity in many types of neuromuscular disease. Severe spinal curvature can cause difficulty in sitting. Conservative and surgical treatment of neuromuscular scoliosis differs from idiopathic scoliosis, being more complex and with a higher complications rate. Non-surgical measures rarely fully control progressive scoliosis, but aim to prevent spinal deformities secondary to muscular hypotonia or contracture. Twenty-four hour bracing should be adjusted throughout growth, and may induce functional impairment and loss of independence. Corrective surgery requires multidisciplinary management and perioperative screening. Pelvic obliquity is commonly associated with neuromuscular scoliosis, making sitting difficult: correction needs to be considered during surgical planning. The goal of surgical correction is to obtain and maintain a well-balanced spine above a well-positioned pelvis. Preoperative multidisciplinary assessment enables potential problems of terrain to be anticipated. Respiratory function investigation will guide possible non-invasive perioperative ventilation. Nutritional and psychosocial assessment should also be incorporated in this preparation, as should overall postoperative care. Implementing this overall strategic planning can achieve a good surgical and functional result in the vast majority of cases.

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.