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

Heart Lung. 2015 Jan-Feb;44(1):15-20. doi: 10.1016/j.hrtlng.2014.10.001. Epub 2014 Nov 13.


Objectives: 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.

Keywords: Critical care; Fatigue; Inspiratory muscle; Mechanical ventilation; Ventilator weaning.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Critical Care
  • Fatigue / epidemiology*
  • Fatigue / etiology
  • Female
  • Humans
  • Intensive Care Units
  • Male
  • Middle Aged
  • Muscle Weakness / epidemiology*
  • Muscle Weakness / etiology
  • Prospective Studies
  • Respiration, Artificial / adverse effects*
  • Ventilator Weaning*
  • Young Adult