title: Assessment of pulmonary function in amyotrophic lateral sclerosis: when can polygraphy help evaluate the need for non-invasive ventilation?
abstract: BACKGROUND
  Non-invasive positive-pressure ventilation (NPPV) is an established, effective, long-term treatment for patients with amyotrophic lateral sclerosis (ALS), but the correct indicators for the establishment of NPPV have not been defined.
  
  
  METHODS
  In this retrospective study, records (spirometry, nocturnal polygraphy, nocturnal blood gases) of 131 patients with ALS were reviewed in order to evaluate the role of polygraphy for prediction of respiratory failure in ALS.
  
  
  RESULTS
  The patient group reporting with versus without dyspnoea had significantly lower values on the revised ALS-Functional Rating Scale (ALSFRS-R), vital capacity (VC), forced VC (FVC), arterial oxygen saturation and arterial oxygen tension readings, including a higher apnoea-hypopnoea index. 23 patients, who did not report about dyspnoea, had an FVC of <75%. Nocturnal hypoventilation was observed in 67% of the patients with ALS independent of their ALSFRS-R. The patient group with nocturnal hypoventilation was characterised by a significantly lower VC, FVC and maximal static inspiratory pressure compared with the group without nocturnal hypoventilation. However, also in the absence of nocturnal hypoventilation, 8 patients had a VC <50% as predicted.
  
  
  CONCLUSIONS
  Our study shows that in patients not reporting dyspnoea and having an FVC of >75%, nocturnal hypoventilation was observed in nearly every second patient. Therefore, for the question of whether NPPV should be initiated, polygraphy does not provide useful additional information if the FVC is already <75% as predicted. However, in patients with more or less normal lung function parameters or where lung spirometry cannot perform adequately (eg, bulbar ALS), it can provide sufficient evidence for the need of NPPV.
authors.affiliation: Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany.
authors.forename: Tino
authors.initials: T
authors.lastname: Prell
authors.affiliation: Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Ringer
authors.affiliation: Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany.
authors.forename: Kara
authors.initials: K
authors.lastname: Wullenkord
authors.affiliation: Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Garrison
authors.affiliation: Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Gunkel
authors.affiliation: Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Stubendorff
authors.affiliation: Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany.
authors.forename: Otto W
authors.initials: OW
authors.lastname: Witte
authors.affiliation: Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Grosskreutz
mesh_terms: D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000401:mortality / Q000503:physiopathology*; D004417:Dyspnea; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D063087:Noninvasive Ventilation / Q000379:methods*; D017286:Polysomnography; D011175:Positive-Pressure Respiration / Q000379:methods*; D012131:Respiratory Insufficiency; D012189:Retrospective Studies; D014797:Vital Capacity