title: Respiratory insufficiency with preserved diaphragmatic function in amyotrophic lateral sclerosis.
abstract: OBJECTIVE
  We performed a longitudinal study to elucidate the correlation between respiratory insufficiency and respiratory biomarkers, including diaphragmatic compound muscle action potential (DCMAP), at the initiation of noninvasive ventilation (NIV) in patients with amyotrophic lateral sclerosis (ALS).
  
  
  METHODS
  The patients were assessed at least every six months. Additional assessments were performed at the start of respiratory therapy when the patients met the criteria for the initiation of NIV. Each assessment consisted of a full neurological examination, a phrenic nerve conduction study, respiratory function tests, and nocturnal pulsed oximetry.
  
  
  METHODS
  We enrolled 43 patients with either definite or probable ALS as defined by the revised El Escorial criteria.
  
  
  RESULTS
  The patients were divided into two groups according to the timing of the initiation of respiratory therapy. Seventeen patients (group A) met the criteria for NIV initiation when their DCMAP remained normal. Twenty-six patients (group B) met the criteria when their DCMAP decreased below normal limits. Although respiratory function parameters were significantly worse in group B compared with group A at NIV initiation, more than 80% of the patients in both groups developed nocturnal desaturation during sleep.
  
  
  CONCLUSIONS
  DCMAP is not always a reliable indicator for determining the optimal timing for NIV initiation during the progression of respiratory insufficiency in ALS. Physicians should be aware of the risk of respiratory insufficiency during sleep in patients with ALS.
authors.affiliation: Department of Neurology, Sapporo Medical University School of Medicine, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Yamauchi
authors.forename: Tomihiro
authors.initials: T
authors.lastname: Imai
authors.forename: Emiko
authors.initials: E
authors.lastname: Tsuda
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Hozuki
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yamamoto
authors.forename: Shun
authors.initials: S
authors.lastname: Shimohama
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications* / Q000503:physiopathology* / Q000628:therapy; D003964:Diaphragm / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D063087:Noninvasive Ventilation; D018579:Patient Selection; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012131:Respiratory Insufficiency / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy