UK physicians’ attitudes and practices in long-term non-invasive ventilation of Duchenne Muscular Dystrophy

Respiratory Insufficiency in Neuromuscular Disease (RIND): A Delphi Study to Establish Consensus Criteria to Define and Diagnose Hypoventilation in Pediatric Neuromuscular Disease

Chronic respiratory failure is a common endpoint in the loss of respiratory muscle function in patients with progressive neuromuscular disease (NMD). Identifying the onset of hypoventilation is critical to allow for the timely introduction of ventilator support and effectively manage respiratory failure [1-3]. While there are accepted criteria governing the diagnosis of hypoventilation during polysomnography (PSG) [4], there is concern that criteria are insufficient for identifying hypoventilation in the earlier stages of respiratory insufficiency related to NMD. The purpose of this project was to identify more sensitive criteria for identifying hypoventilation.

METHODS

Fifteen pediatric pulmonologists with broad experience in managing patients with NMD, 10 of whom were board certified in and practice sleep medicine, were assembled and performed a review of the pertinent literature and a two-round Delphi process with 6 domains (Table 1).

RESULTS

Within the 6 domains there were three pertinent items per domain (Table 2). There was clear agreement on findings on history (morning headaches) and pulmonary function testing (FVC < 50% or awake TcCO2 > 45 mmHg) indicating a high concern for nocturnal hypoventilation. There was close agreement on the definitions for nocturnal hypercapnia and hypoxemia. PSG criteria were identified that indicate a patient is likely in the transitional phase from adequate ventilation to hypoventilation.

DISCUSSION

We identified a set of clinical criteria that may allow for more sensitive diagnosis of hypoventilation in NMD and earlier initiation of non-invasive ventilation leading to a reduction in the respiratory morbidity in progressive NMD. These criteria need to be further and more broadly validated prospectively to confirm their utility.

Decisions for Long-Term Ventilation for Children. Perspectives of Family Members

Rationale: The decision whether to initiate or forgo long-term ventilation for children can be difficult and impactful. However, little has been published on the informational and decisional needs of families facing this decision.Objectives: To assess what families with children with chronic respiratory failure and life-limiting conditions need and want for informed decision-making.Methods: English- and Spanish-speaking parents who were facing (contemporaneous decision makers) or had previously faced (former decision makers) a decision regarding invasive or noninvasive long-term ventilation for their children were recruited using convenience sampling. Patients who were older and cognitively capable also were invited to participate. We performed semistructured interviews using an open-ended interview guide developed de novo to assess parents' decisional needs and experiences. Qualitative data analysis used a thematic approach based on framework analysis, and thematic saturation was a goal.Results: A sample of 44 parents and 2 patients from 43 families was interviewed. All contemporaneous decision makers (n = 28) favored or believed that they would choose long-term ventilation. Fifteen of 16 former decision makers chose long-term ventilation. Thematic saturation was achieved from the perspective of parents who favored or chose long-term ventilation. Four domains were identified: parents' emotional and psychological experiences with decision-making, parents' informational needs, parents' communication and decision support needs, and parents' views on the option not to initiate long-term ventilation. For most parents, making a decision regarding long-term ventilation was stressful, even though they articulated goals and values that could/did guide their decision-making. In general, parents wanted comprehensive information, including what life would be like at home for the child and the family. They wanted their medical providers to be honest, tactful, patient, and supportive. Parents reported that they felt being presented with the option not to initiate was acceptable.Conclusions: In this study, we identified specific informational and decision-making needs regarding long-term ventilation that parents facing decisions feel are important. These data suggest that providers should present families with comprehensive, balanced information on the impact of long-term ventilation and, when the child has a profoundly serious and life-limiting condition, explore the option not to initiate long-term ventilation.

Mortality and respiratory support in X-linked myotubular myopathy: a RECENSUS retrospective analysis

PURPOSE

Individuals with X-linked myotubular myopathy (XLMTM) who survive infancy require extensive supportive care, including ventilator assistance, wheelchairs and feeding tubes. Half die before 18 months of age. We explored respiratory support and associated mortality risk in RECENSUS, particularly among patients ≤5 years old who received respiratory support at birth; this subgroup closely matches patients in the ASPIRO trial of gene therapy for XLMTM.

DESIGN

RECENSUS is an international, retrospective study of patients with XLMTM. Descriptive and time-to-event analyses examined survival on the basis of age, respiratory support, tracheostomy use, predicted mutational effects and life-sustaining care.

RESULTS

Outcomes for 145 patients were evaluated. Among 126 patients with respiratory support at birth, mortality was 47% overall and 59% among those ≤5 years old. Median survival time was shorter for patients ≤5 years old than for those >5 years old (2.2 years (IQR 0.7-5.6) vs 30.2 years (IQR 19.4-30.2)). The most common cause of death was respiratory failure (66.7%). Median survival time was longer for patients with a tracheostomy than for those without (22.8 years (IQR 8.7-30.2) vs 1.8 years (IQR 0.2-not estimable)). The proportion of patients living without a tracheostomy was 50% at age 6 months and 28% at age 2 years. Median survival time was longer with provision of life-sustaining care than without (19.4 years (IQR 3.1-not estimable) vs 0.2 years (IQR 0.1-2.1)).

CONCLUSIONS

High mortality, principally due to respiratory failure, among patients with XLMTM ≤5 years old despite respiratory support underscores the need for early diagnosis, informed decision-making and disease-modifying therapies.

TRIAL REGISTRATION NUMBER

NCT02231697.

Non-invasive Ventilation in Children With Neuromuscular Disease

The respiratory muscles are rarely spared in children with neuromuscular diseases (NMD) which puts them at risk of alveolar hypoventilation. The role of non-invasive ventilation (NIV) is then to assist or "replace" the weakened respiratory muscles in order to correct alveolar hypoventilation by maintaining a sufficient tidal volume and minute ventilation. As breathing is physiologically less efficient during sleep, NIV will be initially used at night but, with the progression of respiratory muscle weakness, NIV can be extended during daytime, preferentially by means of a mouthpiece in order to allow speech and eating. Although children with NMD represent the largest group of children requiring long term NIV, there is a lack of validated criteria to start NIV. There is an agreement to start long term NIV in case of isolated nocturnal hypoventilation, before the appearance of daytime hypercapnia, and/or in case of acute respiratory failure requiring any type of ventilatory support. NIV is associated with a correction in night- and daytime gas exchange, an increase in sleep efficiency and an increase in survival. NIV and/or intermittent positive pressure breathing (IPPB) have been shown to prevent thoracic deformities and consequent thoracic and lung hypoplasia in young children with NMD. NIV should be performed with a life support ventilator appropriate for the child's weight, with adequate alarms, and an integrated (±additional) battery. Humidification is recommended to improve respiratory comfort and prevent drying of bronchial secretions. A nasal interface (or nasal canula) is the preferred interface, a nasobuccal interface can be used with caution in case of mouth breathing. The efficacy of NIV should be assessed on the correction of alveolar ventilation. Patient ventilator synchrony and the absence of leaks can be assessed on a sleep study with NIV or on the analysis of the ventilator's in-built software. The ventilator settings and the interface should be adapted to the child's growth and progression of respiratory muscle weakness. NIV should be associated with an efficient clearance of bronchial secretions by a specific program on the ventilator, IPPB, or mechanical insufflation-exsufflation. Finally, these children should be managed by an expert pediatric multi-disciplinary team.

Measures of respiratory inductance plethysmography (RIP) in children with neuromuscular disease

BACKGROUND

Pulmonary function testing (PFT) is essential for the clinical assessment of respiratory problems. Respiratory inductance plethysmography (RIP) is a non-invasive method of PFT requiring minimal patient cooperation. RIP measures the volumetric change in the ribcage and abdomen, from which work of breathing (WOB) indices are derived. WOB indices include: phase angle (Ф), percent ribcage (RC%), respiratory rate (RR), and labored breathing index (LBI). Heart rate (HR) is collected separately.

AIM

The goal of this study was to assess the utility of a newly developed RIP system, the pneuRIP, in an outpatient clinic setting in children with neuromuscular (NM) disease.

METHOD

The pneuRIP system measures and displays the WOB indices in real-time on an iPad display. Forty-three subjects, 22 NM patients and 21 healthy children (ages: 5-18 years) were enrolled.

RESULTS

Patients' means showed an increase of 119.8% for Ф, 15.7% for LBI, and 19.9% for HR compared with healthy subjects, when adjusted for age and gender. The study found significant differences between the mean values of the healthy subjects and patients in Ф (P = 0.000), LBI (P = 0.001), and HR (P = 0.001). No differences were noted for RC% and RR between groups. Data for Ф in NM patients were diffusely distributed as compared with healthy subjects based on analysis of histograms.

CONCLUSION

Non-invasive pneuRIP testing provided instantaneous PFT results. As compared to healthy subjects, NM patients showed abnormal results with increased markers of thoracoabdominal asynchrony, WOB indices, and biphasic breathing patterns likely resulting from NM weakness.

Advance care discussions with young people affected by life-limiting neuromuscular diseases: A systematic literature review and narrative synthesis

End of life care policy in the UK advocates open discussions between health professionals and patients as the end of life approaches. Despite well documented understanding of the progression of life-limiting neuromuscular diseases, the majority of patients affected by such conditions die without a formal end of life plan in place. We performed a systematic review to investigate conversations regarding end of life care between healthcare professionals and younger adult patients with life-limiting neuromuscular diseases. The search strategy included terms that focused on death and dying along with other factors that could impact length of life. The review found a very limited body of literature regarding end of life care conversations between young people affected by neuromuscular diseases and health professionals. The views and preferences of patients themselves have not been investigated. There is a shared reluctance of patients, family carers and healthcare professionals to initiate end of life care discussions. There are many factors that need to be investigated further in order to develop a consensus that would allow healthcare professionals to engage patients in end of life care conversations allowing them to face the end of their lives with appropriate plans in place.

The value of the CoughAssist® in the daily lives of children with neuromuscular disorders: Experiences of families, children and physiotherapists

OBJECTIVES

We explored parents', children's and physiotherapists' experiences of regular CoughAssist® use, along with their perceptions of its value as an adjunct to in their daily, home respiratory management.

METHODS

All children in the care of a specialist neuromuscular service who regularly used a CoughAssist® device at home participated. Qualitative case study methods involved semi-structured interviews with three children with neuromuscular disorders (NMD), their parents and physiotherapist. Data were analysed using thematic content analysis.

RESULTS

Participants (n = 9) perceived the CoughAssist® held benefits for physical, social and emotional aspects of living with NMD. Poor adherence was identified as the major barrier to effective use, governed by factors including child's resistance, time constraints, treatment preference, practitioner support and fear of pressure trauma.

CONCLUSIONS

Barriers to regular CoughAssist® use must be identified and individually addressed to enable uptake into respiratory care, accurately measure its effectiveness and realise its perceived benefits to children with NMD.

Impact of three genetic musculoskeletal diseases: a comparative synthesis of achondroplasia, Duchenne muscular dystrophy and osteogenesis imperfecta

Achondroplasia, Duchenne muscular dystrophy, and osteogenesis imperfecta are among the most frequent rare genetic disorders affecting the musculoskeletal system in children. Rare genetic disorders are severely disabling and can have substantial impacts on families, children, and on healthcare systems. This literature review aims to classify, summarize and compare these non-medical impacts of achondroplasia, Duchenne muscular dystrophy and osteogenesis imperfecta.

Respiratory muscle decline in Duchenne muscular dystrophy

OBJECTIVES

Duchenne muscular dystrophy (DMD) causes progressive respiratory muscle weakness. The aim of the study was to analyze the trend of a large number of respiratory parameters to gain further information on the course of the disease.

STUDY DESIGN

Retrospective study.

SUBJECT SELECTION

48 boys with DMD, age range between 6 and 19 year old, who were followed in our multidisciplinary neuromuscular clinic between 2001 and 2011.

METHODOLOGY

Lung function, blood gases, respiratory mechanics, and muscle strength were measured during routine follow-up over a 10-year period. Only data from patients with at least two measurements were retained.

RESULTS

The data of 28 patients were considered for analysis. Four parameters showed an important decline with age. Gastric pressure during cough (Pgas cough) was below normal in all patients with a mean decline of 5.7 ± 3.8 cmH2 O/year. Sniff nasal inspiratory pressure (SNIP) tended to increase first followed by a rapid decline (mean decrease 4.8 ± 4.9 cmH2 O; 5.2 ± 4.4% predicted/year). Absolute forced vital capacity (FVC) values peaked around the age of 13-14 years and remained mainly over 1 L but predicted values showed a mean 4.1 ± 4.4% decline/year. Diaphragmatic tension-time index (TTdi) increased above normal values after the age of 14 years with a mean increase of 0.04 ± 0.04 point/year.

CONCLUSIONS

This study confirms the previous findings that FVC and SNIP are among the most important parameters to monitor the evolution of DMD. Expiratory muscle strength, assessed by Pgas cough, and the endurance index, TTdi, which are reported for the first time in a large cohort, appeared to be informative too, even though measured through an invasive method.

Communication regarding breathing support options for youth with Duchenne muscular dystrophy

BACKGROUND

Ventilators for home use, manual and mechanically assisted coughing techniques, and the services of in-home respiratory therapists are options for youth with Duchenne muscular dystrophy (DMD). Evidence supports the use of these modalities, but there seems to be few youth who are receiving these therapies. Is there a knowledge transfer issue? Is there a lack of resources? What is the best way to discuss the issues? What do youth and parents want?

OBJECTIVE

To determine practices, attitudes and beliefs regarding the timing and content of client/family communication related to ventilatory support decisions for individuals with DMD.

METHODS

A questionnaire was sent to all 19 children's treatment centres in Ontario. The lead clinician responded on behalf of his or her centre. Another questionnaire was given to 11 families who attended a parent support meeting.

RESULTS

Respondents from the treatment centres who provide services for youth with DMD indicated that there are resources in terms of personnel and an obligation to provide information about ventilatory support, but provision of information is often late and/or inconsistent. The family respondents wanted more information and they wanted it earlier than they are currently receiving it.

CONCLUSIONS

Parents and youth dealing with DMD have many resources at their disposal in Ontario. The evidence is clear that there are long-term health benefits to providing ventilatory support as well as instruction in coughing assistance. Due to the classical nature of disease progression in DMD, information should be provided within reasonable timelines.

The role of respiratory management of Pompe disease

Respiratory failure is an unavoidable event in the natural history of some neuromuscular diseases, while appearing very infrequently in others. In some cases, such as Pompe disease, respiratory failure progresses more rapidly than motor impairment, sometimes being the onset event. Home mechanical ventilation improves survival and quality of life of these patients, with a reduction in healthcare costs. Therefore, pulmonologists must improve their skills in order to play a more relevant role in the care of these patients. The aim of this statement is to provide pulmonologists with some simple information in order for them to fulfil their role of primary caregiver, enabling appropriate and rapid diagnosis and treatment.

Ethical challenges in the care of children and families affected by life-limiting neuromuscular diseases

OBJECTIVE

We sought to understand how neuromuscular clinicians respond to the ethical challenges that arise in caring for children with life-limiting neuromuscular diseases.

METHODS

We conducted a national survey of interdisciplinary professionals who care for children with Duchenne Muscular Dystrophy and Spinal Muscular Atrophy Type-1 to document their knowledge, attitudes, beliefs and reported practices with regard to prominent ethical challenges, and their suggestions for ethics interventions that would assist them in improving clinical practice.

RESULTS

157 participants completed paper or electronic surveys for an overall participation rate of 24%. A significant minority of respondents were either unaware of or chose not to adopt relevant ethical guidelines, and reported experiencing crises of conscience in the care of their patients. In response to 8 ethical dilemmas, there was variability in how often respondents encountered them, their comfort in addressing them, and their reported practices, including only 24% who have requested ethics consultation.

CONCLUSION

Training of interdisciplinary clinicians is needed to improve their adoption of relevant ethical guidelines, cultivate greater awareness of diverse attitudes regarding the ethical permissibility of different treatment options and the utility of ethics consultation, and foster greater confidence and competence in responding to ethical challenges that arise in pediatric neuromuscular practice.

Home mechanical ventilation: a Canadian Thoracic Society clinical practice guideline

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

Recent Advances in Respiratory Care for Neuromuscular Disease

The impact of ventilatory support on the natural history of neuromuscular disease (NMD) has become clearer over the last 2 decades as techniques have been more widely applied. Noninvasive ventilation (NIV) allows some patients with nonprogressive pathology to live to nearly normal life expectancy, extends survival by many years in patients with other conditions (eg, Duchenne muscular dystrophy), and in those patients with rapidly deteriorating disease (eg, amyotrophic lateral sclerosis) survival may be increased, but symptoms can be palliated even if mortality is not reduced. A growing number of children with NMD are surviving to adulthood with the aid of ventilatory support. The combination of NIV with cough-assist techniques decreases pulmonary morbidity and hospital admissions. Trials have confirmed that NIV works in part by enhancing chemosensitivity, and in patients with many different neuromuscular conditions the most effective time to introduce NIV is when symptomatic sleep-disordered breathing develops.