title: Weaned but weary: one third of adult intensive care patients mechanically ventilated for 7 days or more have impaired inspiratory muscle endurance after successful weaning.
abstract: OBJECTIVE
  The purpose of this study was to establish whether intensive care unit (ICU) patients have impaired inspiratory muscle (IM) endurance immediately following weaning from prolonged mechanical ventilation (MV), and whether IM weakness is related to function or perceived exertion.
  
  
  BACKGROUND
  Impaired IM endurance may hinder recovery from MV, however it is unknown whether this affects patients' function or perceived exertion.
  
  
  METHODS
  Prospective observational study of 43 adult ICU patients following weaning from MV (>7 days duration). IM endurance was measured using the fatigue resistance index (FRI).
  
  
  RESULTS
  IM endurance was impaired (FRI = mean 0.90, SD 0.31), with 37% scoring below 0.80. IM strength did not significantly correlate with function (r = 0.24, p = 0.12) or perceived exertion during exercise (r = -0.146, p = 0.37).
  
  
  CONCLUSIONS
  IM endurance is reduced in one third of patients, while IM weakness does not appear closely associated with function or perceived exertion immediately following successful weaning.
authors.affiliation: School of Medicine, University of Queensland, Australia; Discipline of Physiotherapy, University of Canberra, Australia; Physiotherapy Department, Canberra Hospital, Australia. Electronic address: Bernie.Bissett@act.gov.au.
authors.forename: Bernie
authors.initials: B
authors.lastname: Bissett
authors.affiliation: Intensive Care Unit, Canberra Hospital, Australia; School of Medicine, Australian National University, Australia.
authors.forename: I Anne
authors.initials: IA
authors.lastname: Leditschke
authors.affiliation: Statistical Consulting Unit, Australian National University, Australia.
authors.forename: Teresa
authors.initials: T
authors.lastname: Neeman
authors.affiliation: School of Medicine, University of Queensland, Australia; Intensive Care Unit, Royal Brisbane and Women's Hospital, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Boots
authors.affiliation: Intensive Care Unit, Royal Brisbane and Women's Hospital, Australia; School of Allied Health Sciences, Griffith University, Australia.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Paratz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003422:Critical Care; D005221:Fatigue / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000453:epidemiology* / Q000209:etiology; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000009:adverse effects*; D015300:Ventilator Weaning; D055815:Young Adult
keywords: Critical care; Fatigue; Inspiratory muscle; Mechanical ventilation; Ventilator weaning