Respiratory Complications in ALS
Condition: Motor Neuron Disease; Pneumonia
MeSH terms: Motor Neuron Disease; Amyotrophic Lateral Sclerosis
Study type: Observational

Summary: 
      Respiratory failure is the leading cause of death in motor neuron disease (MND) patients.
      Symptoms of respiratory dysfunction in MND patients include sleep disturbance, excessive
      daytime somnolence, morning headaches and cognitive changes. Almost all MND patients will
      develop respiratory problems during the course of their disease. In a small percentage of MND
      patients, respiratory failure may present as the primary symptom at onset, whereas more
      commonly it develops later in the disease.
    

Detailed description: 
      Respiratory failure is the leading cause of death in motor neuron disease (MND) patients.
      Symptoms of respiratory dysfunction in MND patients include sleep disturbance, excessive
      daytime somnolence, morning headaches and cognitive changes. Almost all MND patients will
      develop respiratory problems during the course of their disease. In a small percentage of MND
      patients, respiratory failure may present as the primary symptom at onset, whereas more
      commonly it develops later in the disease. (1) Forced vital capacity (FVC), taken either
      supine or erect, is the most commonly used measurement tool of respiratory function. Such
      measures are well recognized predictors of survival (2), with supine FVC a more accurate
      marker of diaphragmatic weakness (1). However, FVC may not be sensitive for the detection of
      early respiratory failure and can be technically difficult to perform in patients with severe
      bulbar weakness (3). Other respiratory measures include maximal inspiratory pressure (MIP),
      maximal expiratory pressure (MEP), sniff nasal inspiratory pressure (SNIP) and, less
      commonly, formal assessment of arterial blood gases (ABG). Interpretation of the trends of
      these measures over time, combined with the clinical picture, determines appropriate
      respiratory management. Significantly, the advent of non-invasive ventilation (NIV) has
      provided clear benefit in terms of improving symptoms, QOL and prolonging survival by up to 7
      months in MND patients, making NIV a central armamentarium of respiratory management in these
      patients (4) Bilevel ventilation devices (Bi-PAP) are most commonly used as initial therapy.
      There are no established evidence-based guidelines regarding optimal timing for initiation of
      NIV.Some studies suggest that an early introduction of NIV may increase survival (5), reduce
      respiratory-related energy expenditure (6) and improve adherence to therapy and QOL (7).Once
      initiated, poor optimisation of NIV represents an independent risk factor for mortality (8)
      However, there are no randomized control trial data available that have compared the specific
      parameters of bilevel modes of ventilation across various patient cohorts. Different
      strategies have been used to optimize patient comfort, including adjusting the type of mask
      and fittings, providing humidified air and testing different Bi-PAP pressure settings.
      Despite these measures, up to 30% of MND patients cannot tolerate therapy due to secondary
      effects of anxiety, emotional lability from pseudobulbar palsy, excessive salivation,
      claustrophobia and nasal bridge soreness (8) Importantly, the key factors that affect overall
      compliance with this treatment are the presence of bulbar dysfunction with bulbar onset
      patients six times less likely to tolerate NIV than those with limb onset disease (9) Future
      efforts must be focused on determining more accurate testing for early respiratory failure,
      optimal time to initiate NIV and the comfortable adaptation of NIV devices for patients with
      bulbar weakness
    

Intervention name(s): Questionaires
Intervention type(s): Other
Intervention description(s): Any validated functional rating scale, such as the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) or the ALSFRS-Revised (if available)
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        Patient population with ALS