The effects of lung volume recruitment therapy on respiratory function and quality of life in people with neuromuscular disease

© 2020 Nicole Louise SheersRespiratory muscle weakness results in substantial discomfort, disability and ultimately death in many neuromuscular diseases (NMDs). Respiratory compromise manifests as some or all of, shallow breathing, poor cough and associated difficulty clearing mucus, respiratory tract infections, hypoventilation, sleep-disordered breathing and chronic ventilatory failure. As survival outcomes improve for many NMDs, there is a shift towards more proactive and preventative chronic disease multi-disciplinary care models that manage symptoms, improve morbidity and reduce mortality. Unfortunately, clinical care guidelines for chronic NMD care are based largely on clinical rationale and consensus opinion rather than level A evidence. These guidelines typically recommend therapies to enhance lung inflation and cough effectiveness, however there is minimal evidence that performing techniques regularly is beneficial. Lung volume recruitment (LVR) is one such therapy. Simple, inexpensive and widely-accessible, it delivers air via a manual resuscitation bag to augment lung inflation above a person’s own deepest breath. Given the absence of prospective controlled research, this thesis aimed to investigate the effect of regular LVR in people with NMD. Firstly, a cross-sectional cohort study of 80 community-dwelling adults with NMD and respiratory system impairment identified that participants with slowly-progressive forms of NMD have smaller lung volumes and respiratory system compliance (Crs) than participants with rapidly-progressive motor neurone disease, despite having a similar degree of respiratory muscle weakness. Stiffness was associated with smaller lung volume in long-standing NMD, supporting the hypothesis that maintaining lung volume and Crs may ameliorate respiratory decline. The second component of this thesis confirmed the feasibility of LVR; 95% of participants naïve to the therapy could successfully augment their lung insufflation capacity (LIC, the maximum inflation capacity obtained by assisting inflation). Moreover, LIC and Crs increased following a single-session of LVR therapy. These immediate effects were only evident when naïve; when assessed three-months later there was no change in respiratory function following a single-session of LVR. The third and primary component of this work, a randomised controlled trial of twice-daily LVR or an active control treatment for three-months, found a statistically significant difference in LIC between groups favouring LVR. No demonstrable change in lung volumes, respiratory muscle strength, symptoms or quality of life was found, suggesting a learning effect or acclimatisation to higher inflation pressures may be responsible for the increase. However, an improvement in Crs predominantly in the LVR group means a beneficial effect on underlying respiratory mechanics cannot be excluded, especially if conducted for a longer duration. Notwithstanding the need for further longitudinal studies, the observed improvement in the primary outcome of LIC in the absence of apparent harm or burden, provides robust preliminary data supporting clinical recommendations and practice that regular LVR be performed by people living with NMD. The clinical significance of a higher LIC is still to be fully realised, but this thesis has demonstrated an effect that is compatible with the clinical and biologically-plausible rationale for this therapy

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

International audienceThis 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 peopl

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